Publications by authors named "Carmine De Angelis"

45 Publications

Case Report: Detection of a Novel Germline Deletion in a Young Woman With Hereditary Breast Cancer: When the Patient's Phenotype History Doesn't Lie.

Front Oncol 2021 24;11:602523. Epub 2021 Feb 24.

Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy.

The partner and localizer of () is a major binding partner that participates in homologous recombination repair in response to DNA double-strand breaks. Germline alterations of the gene have recently been associated with a high risk of developing breast cancer. We investigated a 37-year-old Caucasian woman with breast cancer and family history of breast cancer using targeted next generation sequencing. A novel heterozygous deletion involving exons 5 and 6 was found in the gene, and resulted in the production of a truncated PALB2 protein. These findings expand the mutational spectra of -associated breast cancer, and may improve the mutation-based screening and genetic diagnosis of breast cancer.
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http://dx.doi.org/10.3389/fonc.2021.602523DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7943848PMC
February 2021

Activation of the IFN Signaling Pathway is Associated with Resistance to CDK4/6 Inhibitors and Immune Checkpoint Activation in ER-Positive Breast Cancer.

Clin Cancer Res 2021 Feb 3. Epub 2021 Feb 3.

Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas.

Purpose: Cyclin-dependent kinase 4 (CDK4) and CDK6 inhibitors (CDK4/6i) are highly effective against estrogen receptor-positive (ER)/HER2 breast cancer; however, intrinsic and acquired resistance is common. Elucidating the molecular features of sensitivity and resistance to CDK4/6i may lead to identification of predictive biomarkers and novel therapeutic targets, paving the way toward improving patient outcomes.

Experimental Design: Parental breast cancer cells and their endocrine-resistant derivatives (EndoR) were used. Derivatives with acquired resistance to palbociclib (PalboR) were generated from parental and estrogen deprivation-resistant MCF7 and T47D cells. Transcriptomic and proteomic analyses were performed in palbociclib-sensitive and PalboR lines. Gene expression data from CDK4/6i neoadjuvant trials and publicly available datasets were interrogated for correlations of gene signatures and patient outcomes.

Results: Parental and EndoR breast cancer lines showed varying degrees of sensitivity to palbociclib. Transcriptomic analysis of these cell lines identified an association between high IFN signaling and reduced CDK4/6i sensitivity; thus an "IFN-related palbociclib-resistance Signature" (IRPS) was derived. In two neoadjuvant trials of CDK4/6i plus endocrine therapy, IRPS and other IFN-related signatures were highly enriched in patients with tumors exhibiting intrinsic resistance to CDK4/6i. PalboR derivatives displayed dramatic activation of IFN/STAT1 signaling compared with their short-term treated or untreated counterparts. In primary ER/HER2 tumors, the IRPS score was significantly higher in lumB than lumA subtype and correlated with increased gene expression of immune checkpoints, endocrine resistance, and poor prognosis.

Conclusions: Aberrant IFN signaling is associated with intrinsic resistance to CDK4/6i. Experimentally, acquired resistance to palbociclib is associated with activation of the IFN pathway, warranting additional studies to clarify its involvement in resistance to CDK4/6i.
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http://dx.doi.org/10.1158/1078-0432.CCR-19-4191DOI Listing
February 2021

A review of the use of next generation sequencing methodologies to identify biomarkers of resistance to CDK4/6 inhibitors in ER+/HER2- breast cancer.

Crit Rev Oncol Hematol 2021 Jan 9;157:103191. Epub 2020 Dec 9.

Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy. Electronic address:

The development of cyclin-dependent kinases (CDK) 4 and 6 inhibitors represented a substantial breakthrough in the treatment of estrogen receptor positive (ER+), human epidermal growth factor receptor 2 (HER2) negative metastatic breast cancer. These drugs showed a significant clinical benefit in pivotal clinical trials. However, resistance eventually occurs, leading to disease progression. Next Generation Sequencing methodologies have been employed to investigate predictive biomarkers of response or resistance to CDK4/6 inhibitors. Whole exome and targeted sequencing of solid and liquid biopsies have revealed several possible genomic alterations associated with resistance. Notably, genomic alterations identified by DNA-sequencing did not fully recapitulate the entire landscape of resistance to CDK4/6 inhibitors. Gene expression analysis, such as RNA-Seq methodologies, have provided insights into transcriptional profiles and may need further application. Herein, we report the main findings derived from the use of NGS analysis in the context of resistance to CDK4/6 inhibitors in ER + breast cancer.
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http://dx.doi.org/10.1016/j.critrevonc.2020.103191DOI Listing
January 2021

Optimising triage procedures for patients with cancer needing active anticancer treatment in the COVID-19 era.

ESMO Open 2020 09;5(5):e000885

Department of Clinical Medicine and Surgery, University of Naples Federico II, Napoli, Campania, Italy.

Background: Immunosuppression induced by anticancer therapy in a COVID-19-positive asymptomatic patient with cancer may have a devastating effect and, eventually, be lethal. To identify asymptomatic cases among patients receiving active cancer treatment, the Federico II University Hospital in Naples performs rapid serological tests in addition to hospital standard clinical triage for COVID-19 infection.

Methods: From 6 to 17 April 2020, all candidates for chemotherapy, radiotherapy or target/immunotherapy, if negative at the standard clinical triage on the day scheduled for anticancer treatment, received a rapid serological test on peripheral blood for COVID-19 IgM and IgG detection. In case of COVID-19 IgM and/or IgG positivity, patients underwent a real-time PCR (RT-PCR) SARS-CoV-2 test to confirm infection, and active cancer treatment was delayed.

Results: Overall 466 patients, negative for COVID-19 symptoms, underwent serological testing in addition to standard clinical triage. The average age was 61 years (range 25-88 years). Most patients (190, 40.8%) had breast cancer, and chemotherapy with or without immunotherapy was administered in 323 (69.3%) patients. Overall 433 (92.9%) patients were IgG-negative and IgM-negative, and 33 (7.1%) were IgM-positive and/or IgG-positive. Among the latter patients, 18 (3.9%), 11 (2.4%) and 4 (0.9%) were IgM-negative/IgG-positive, IgM-positive/IgG-negative and IgM-positive/IgG-positive, respectively. All 33 patients with a positive serological test, tested negative for RT-PCR SARS-CoV-2 test. No patient in our cohort developed symptoms suggestive of active COVID-19 infection.

Conclusion: Rapid serological testing at hospital admission failed to detect active asymptomatic COVID-19 infection. Moreover, it entailed additional economic and human resources, delayed therapy administrationand increased hospital accesses.
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http://dx.doi.org/10.1136/esmoopen-2020-000885DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7507249PMC
September 2020

Metabolic syndrome and early stage breast cancer outcome: results from a prospective observational study.

Breast Cancer Res Treat 2020 Jul 4;182(2):401-409. Epub 2020 Jun 4.

Department of Clinical Medicine and Surgery, Oncology Division, University of Naples Federico II, Naples, Italy.

Purpose: Obesity and insulin resistance have been associated with poor prognosis in breast cancer (BC). The present prospective study aimed to investigate the impact of metabolic syndrome (MetS) and its components on early BC (eBC) patients' outcome.

Methods: MetS was defined by the presence of 3 to 5 of the following components: waist circumference > 88 cm, blood pressure ≥ 130/≥ 85 mmHg, serum levels of triglycerides ≥ 150 mg/dL, high density lipoprotein < 50 mg/dL and fasting glucose ≥ 110 mg/dL. Seven hundred and seventeen patients with data on ≥ 4 MetS components at BC diagnosis were enrolled. Study population was divided into two groups: patients with < 3 (non-MetS) vs. ≥ 3 components (MetS). Categorical variables were analyzed by Chi-square test and survival data by log-rank test and Cox proportional hazards regression model.

Results: Overall, 544 (75.9%) and 173 (24.1%) women were categorized as non-MetS and MetS, respectively. MetS patients were more likely to be older, postmenopausal, and insulin-resistant compared to non-MetS patients (p < 0.05). In multivariate analysis, MetS patients had a numerically higher risk of relapse [disease-free survival (DFS), hazard ratio (HR) 1.51, p = 0.07] and a significantly higher risk of death compared to non-MetS patients [overall survival (OS), HR 3.01, p < 0.0001; breast cancer-specific survival (BCSS), HR 3.16, p = 0.001]. Additionally, patients with 1 to 2 components of MetS had an increased risk of dying compared to patients with 0 components (OS, HR 4.90, p = 0.01; BCSS, HR 6.07, p = 0.02).

Conclusions: MetS correlated with poor outcome in eBC patients. Among patients without full criteria for MetS diagnosis, the presence of 1 or 2 components of the syndrome may predict for worse survival.
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http://dx.doi.org/10.1007/s10549-020-05701-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7297840PMC
July 2020

Enhancer reprogramming driven by high-order assemblies of transcription factors promotes phenotypic plasticity and breast cancer endocrine resistance.

Nat Cell Biol 2020 06 18;22(6):701-715. Epub 2020 May 18.

Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.

Acquired therapy resistance is a major problem for anticancer treatment, yet the underlying molecular mechanisms remain unclear. Using an established breast cancer cellular model, we show that endocrine resistance is associated with enhanced phenotypic plasticity, indicated by a general downregulation of luminal/epithelial differentiation markers and upregulation of basal/mesenchymal invasive markers. Consistently, similar gene expression changes are found in clinical breast tumours and patient-derived xenograft samples that are resistant to endocrine therapies. Mechanistically, the differential interactions between oestrogen receptor α and other oncogenic transcription factors, exemplified by GATA3 and AP1, drive global enhancer gain/loss reprogramming, profoundly altering breast cancer transcriptional programs. Our functional studies in multiple culture and xenograft models reveal a coordinated role of GATA3 and AP1 in re-organizing enhancer landscapes and regulating cancer phenotypes. Collectively, our study suggests that differential high-order assemblies of transcription factors on enhancers trigger genome-wide enhancer reprogramming, resulting in transcriptional transitions that promote tumour phenotypic plasticity and therapy resistance.
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http://dx.doi.org/10.1038/s41556-020-0514-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7737911PMC
June 2020

Palbociclib added to ongoing endocrine therapy for hormone receptor-positive HER2-negative metastatic breast cancer: A case report series.

Mol Clin Oncol 2020 May 11;12(5):456-460. Epub 2020 Mar 11.

Department of Clinical Medicine and Surgery, University of Naples 'Federico II', I-80131 Naples, Italy.

Palbociclib is a potent cyclin-dependent kinase (CDK)4/6 inhibitor that disrupts cell cycle progression and has been recently approved in combination with an aromatase inhibitor or fulvestrant as first- and second-line treatment in hormone receptor (HR), human epidermal growth factor receptor (HER)2 metastatic breast cancer. There is evidence that palbociclib may reverse endocrine therapy resistance and that it may also be added to ongoing endocrine therapy beyond progression to obtain clinical benefit. The aim of the present study was to explore this possibility in 5 patients who received palbociclib + fulvestrant following disease progression while under treatment with fulvestrant alone. The median progression-free survival was not reached during a median follow-up of 25 months, and the most frequent best response was stable disease. Three patients remained under treatment on the last re-evaluation. All patients had highly endocrine-sensitive disease and had previously received fulvestrant for ≥12 months. The hypothesis that a selected subpopulation of patients with HR/HER2 metastatic breast cancer may benefit from the addition of palbociclib to ongoing endocrine therapy beyond disease progression merits further investigation.
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http://dx.doi.org/10.3892/mco.2020.2016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7087462PMC
May 2020

Estrogen-induced transcription at individual alleles is independent of receptor level and active conformation but can be modulated by coactivators activity.

Nucleic Acids Res 2020 02;48(4):1800-1810

Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.

Steroid hormones are pivotal modulators of pathophysiological processes in many organs, where they interact with nuclear receptors to regulate gene transcription. However, our understanding of hormone action at the single cell level remains incomplete. Here, we focused on estrogen stimulation of the well-characterized GREB1 and MYC target genes that revealed large differences in cell-by-cell responses, and, more interestingly, between alleles within the same cell, both over time and hormone concentration. We specifically analyzed the role of receptor level and activity state during allele-by-allele regulation and found that neither receptor level nor activation status are the determinant of maximal hormonal response, indicating that additional pathways are potentially in place to modulate cell- and allele-specific responses. Interestingly, we found that a small molecule inhibitor of the arginine methyltransferases CARM1 and PRMT6 was able to increase, in a gene specific manner, the number of active alleles/cell before and after hormonal stimulation, suggesting that mechanisms do indeed exist to modulate hormone receptor responses at the single cell and allele level.
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http://dx.doi.org/10.1093/nar/gkz1172DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7039002PMC
February 2020

Immune Response Against Head and Neck Cancer: Biological Mechanisms and Implication on Therapy.

Transl Oncol 2020 Feb 21;13(2):262-274. Epub 2019 Dec 21.

Head and Neck Medical Oncology Unit, Istituto Nazionale Tumori, IRCCS Fondazione G. Pascale, Naples, Italy.

Head and neck carcinoma (HNC) are diseases arising from several tracts of the aerodigestive ways. Most HNC are squamous cell carcinoma (SCCHN). Immunotherapy is a treatment strategy aimed to reinforce the immune system. Several types of immunotherapy are available in the clinical scenario. Checkpoint inhibitors were developed later in SCCHN; nivolumab and pembrolizumab have reached the clinical approval, having both drugs demonstrated to significantly improve the overall survival, if compared with the standard of treatment (according to the results of the CheckMate 141 and KEYNOTE-040 trials). Nevertheless, immunotherapy may fail because of the genetics of SCCHN. In fact, two genetically different types of SCCHN have been discovered, one virus-related (HPV) and the other mutagens-related. They seem to show in clinical trials very different responses to immunotherapy. Given the existence of a number of factors predictive of response to immunotherapy in SCCHN, a future clinical approach may be to characterize the genetic and immunologic feature of SCCHN and to perform a well-tailored immunotherapy. This review will summarize the main immunotherapy strategies available in SCCHN, discussing their real efficacy, highlighting also the ways to improve them.
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http://dx.doi.org/10.1016/j.tranon.2019.11.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6931206PMC
February 2020

Towards personalized treatment for early stage HER2-positive breast cancer.

Nat Rev Clin Oncol 2020 04 13;17(4):233-250. Epub 2019 Dec 13.

Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX, USA.

Advances in HER2-targeted therapies have improved the survival of patients with HER2-positive breast cancer. The standard-of-care treatment for localized disease has been chemotherapy and 1 year of adjuvant HER2-targeted therapy, typically with the anti-HER2 antibody trastuzumab. Despite the effectiveness of this treatment, disease relapse occurs in a subset of patients; thus, focus has been placed on escalating treatment by either combining different HER2-targeted agents or extending the duration of HER2-targeted therapy. Indeed, dual HER2-targeted therapies and extended-duration anti-HER2 therapy, as well as adjuvant therapy with the anti-HER2 antibody-drug conjugate T-DM1, have all been approved for clinical use. Emerging evidence suggests, however, that some patients do not derive sufficient benefit from these additional therapies to offset the associated toxicities and/or costs. Similarly, the universal use of chemotherapy might not benefit all patients, and treatment de-escalation through omission of chemotherapy has shown promise in clinical trials and is currently being explored further. The future of precision medicine should therefore involve tailoring of therapy based on the genetics and biology of each tumour and the clinical characteristics of each patient. Predictive biomarkers that enable the identification of patients who will benefit from either escalated or de-escalated treatment will be crucial to this approach. In this Review, we summarize the available HER2-targeted agents and associated mechanisms of resistance, and describe the current therapeutic landscape of early stage HER2-positive breast cancer, focusing on strategies for treatment escalation or de-escalation.
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http://dx.doi.org/10.1038/s41571-019-0299-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8023395PMC
April 2020

FOXA1 upregulation promotes enhancer and transcriptional reprogramming in endocrine-resistant breast cancer.

Proc Natl Acad Sci U S A 2019 Dec 11. Epub 2019 Dec 11.

Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX 77030;

Forkhead box A1 (FOXA1) is a pioneer factor that facilitates chromatin binding and function of lineage-specific and oncogenic transcription factors. Hyperactive FOXA1 signaling due to gene amplification or overexpression has been reported in estrogen receptor-positive (ER) endocrine-resistant metastatic breast cancer. However, the molecular mechanisms by which FOXA1 up-regulation promotes these processes and the key downstream targets of the FOXA1 oncogenic network remain elusive. Here, we demonstrate that FOXA1 overexpression in ER breast cancer cells drives genome-wide enhancer reprogramming to activate prometastatic transcriptional programs. Up-regulated FOXA1 employs superenhancers (SEs) to synchronize transcriptional reprogramming in endocrine-resistant breast cancer cells, reflecting an early embryonic development process. We identify the hypoxia-inducible transcription factor hypoxia-inducible factor-2α (HIF-2α) as the top high FOXA1-induced SE target, mediating the impact of high FOXA1 in activating prometastatic gene sets and pathways associated with poor clinical outcome. Using clinical ER/HER2 metastatic breast cancer datasets, we show that the aberrant FOXA1/HIF-2α transcriptional axis is largely nonconcurrent with the mutations, suggesting different mechanisms of endocrine resistance and treatment strategies. We further demonstrate the selective efficacy of an HIF-2α antagonist, currently in clinical trials for advanced kidney cancer and recurrent glioblastoma, in reducing the clonogenicity, migration, and invasion of endocrine-resistant breast cancer cells expressing high FOXA1. Our study has uncovered high FOXA1-induced enhancer reprogramming and HIF-2α-dependent transcriptional programs as vulnerable targets for treating endocrine-resistant and metastatic breast cancer.
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http://dx.doi.org/10.1073/pnas.1911584116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6936436PMC
December 2019

TBCRC023: A Randomized Phase II Neoadjuvant Trial of Lapatinib Plus Trastuzumab Without Chemotherapy for 12 versus 24 Weeks in Patients with HER2-Positive Breast Cancer.

Clin Cancer Res 2020 02 29;26(4):821-827. Epub 2019 Oct 29.

Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas.

Purpose: Prior neoadjuvant trials with 12 weeks of dual anti-HER2 therapy without chemotherapy demonstrated a meaningful pathologic complete response (pCR) in patients with HER2-positive breast cancer. In this trial, we sought to determine whether longer treatment would increase the rate of pCR.

Patients And Methods: TBCRC023 (NCT00999804) is a randomized phase II trial combining a Simon phase II design in the experimental arm with a pick-the-winner design, not powered for direct comparison. Women with HER2-positive breast tumors measuring ≥2 cm (median = 5 cm) were randomized in a 1:2 ratio to 12 versus 24 weeks of lapatinib and trastuzumab. Letrozole (along with ovarian suppression if premenopausal) was administered in patients whose tumors were also estrogen receptor (ER) positive. All evaluable patients were assessed for in-breast pCR.

Results: Ninety-seven patients were enrolled (33 in 12-week arm and 64 in 24-week arm), of whom 94 were evaluable. Median age was 51 years, and 55% were postmenopausal. Median tumor size was 5 cm, and 65% were ER-positive. The rate of pCR in the 24-week arm was 28% and numerically superior to the 12-week arm (12%). This was driven by increased pCR in the ER-positive subgroup (33% vs. 9%). Study treatment was well tolerated, with grade 1-2 diarrhea and acneiform rash being the most common toxicities.

Conclusions: Treatment with dual anti-HER2 therapy for 24 weeks led to a numeric increase in pCR rate in women with HER2-positive breast cancer, without using chemotherapy. If validated, this approach may help identify patients who may benefit from deescalation of therapy.
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http://dx.doi.org/10.1158/1078-0432.CCR-19-0851DOI Listing
February 2020

Evaluation of the Predictive Role of Tumor Immune Infiltrate in Patients with HER2-Positive Breast Cancer Treated with Neoadjuvant Anti-HER2 Therapy without Chemotherapy.

Clin Cancer Res 2020 02 25;26(3):738-745. Epub 2019 Oct 25.

Lester and Sue Smith Breast Center and Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas.

Purpose: Tumor-infiltrating lymphocytes (TIL) are associated with benefit to trastuzumab and chemotherapy in patients with early-stage HER2 breast cancer. The predictive value of TILs, TIL subsets, and other immune cells in patients receiving chemotherapy-sparing lapatinib plus trastuzumab treatment is unclear. Hematoxylin and eosin-stained slides ( = 59) were used to score stromal (s-)TILs from pretreatment biopsies of patients enrolled in the neoadjuvant TBCRC006 trial of 12-week lapatinib plus trastuzumab therapy (plus endocrine therapy for ER tumors). A 60% threshold was used to define lymphocyte-predominant breast cancer (LPBC). Multiplexed immunofluorescence (m-IF) staining (CD4, CD8, CD20, CD68, and FoxP3) and multispectral imaging were performed to characterize immune infiltrates in single formalin-fixed paraffin-embedded slides ( = 33).

Results: The pathologic complete response (pCR) rate was numerically higher in patients with LPBC compared with patients with non-LPBC (50% vs. 19%, = 0.057). Unsupervised hierarchical clustering of the five immune markers identified two patient clusters with different responses to lapatinib plus trastuzumab treatment (pCR = 7% vs. 50%, for cluster 1 vs. 2 respectively; = 0.01). In multivariable analysis, cluster 2, characterized by high CD4, CD8, CD20 s-TILs, and high CD20 intratumoral TILs, was independently associated with a higher pCR rate ( = 0.03). Analysis of single immune subpopulations revealed a significant association of pCR with higher baseline infiltration by s-CD4, intratumoral (i-) CD4, and i-CD20 TILs.

Conclusions: LPBC was marginally associated with higher pCR rate than non-LPBC in patients with lapatinib plus trastuzumab treated HER2 breast cancer. Quantitative assessment of the immune infiltrate by m-IF is feasible and may help correlate individual immune cell subpopulations and immune cell profiles with treatment response.
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http://dx.doi.org/10.1158/1078-0432.CCR-19-1402DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7002194PMC
February 2020

A CTC-Cluster-Specific Signature Derived from OMICS Analysis of Patient-Derived Xenograft Tumors Predicts Outcomes in Basal-Like Breast Cancer.

J Clin Med 2019 10 24;8(11). Epub 2019 Oct 24.

Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, TX 77204, USA.

Circulating tumor cell clusters (CTCcl) have a higher metastatic potential compared to single CTCs and predict long-term outcomes in breast cancer (BC) patients. Because of the rarity of CTCcls, molecular characterization of primary tumors that give rise to CTCcl hold significant promise for better diagnosis and target discovery to combat metastatic BC. In our study, we utilized the reverse-phase protein array (RPPA) and transcriptomic (RNA-Seq) data of 10 triple-negative BC patient-derived xenograft (TNBC PDX) transplantable models with CTCs and evaluated expression of upregulated candidate protein Bcl2 (B-cell lymphoma 2) by immunohistochemistry (IHC). The sample-set consisted of six CTCcl-negative (CTCcl-) and four CTCcl-positive (CTCcl+) models. We analyzed the RPPA and transcriptomic profiles of CTCcl- and CTCcl+ TNBC PDX models. In addition, we derived a CTCcl-specific gene signature for testing if it predicted outcomes using a publicly available dataset from 360 patients with basal-like BC. The RPPA analysis of CTCcl+ vs. CTCcl- TNBC PDX tumors revealed elevated expression of Bcl2 (false discovery rate (FDR) < 0.0001, fold change (FC) = 3.5) and reduced acetyl coenzyme A carboxylase-1 (ACC1) (FDR = 0.0005, FC = 0.3) in CTCcl+ compared to CTCcl- tumors. Genome-wide transcriptomic analysis of CTCcl+ vs. CTCcl- tumors revealed 549 differentially expressed genes associated with the presence of CTCcls. Apoptosis was one of the significantly downregulated pathways (normalized enrichment score (NES) = -1.69; FDR < 0.05) in TNBC PDX tumors associated with CTCcl positivity. Two out of four CTCcl+ TNBC PDX primary tumors had high Bcl2 expression by IHC (H-score > 34); whereas, only one of six CTCcl- TNBC PDX primary tumors met this criterion. Evaluation of epithelial-mesenchymal transition (EMT)-specific signature did not show significant differences between CTCcl+ and CTCcl- tumors. However, a gene signature associated with the presence of CTCcls in TNBC PDX models was associated with worse relapse-free survival in the publicly available dataset from 360 patients with basal-like BC. In summary, we identified the multigene signature of primary PDX tumors associated with the presence of CTCcls. Evaluation of additional TNBC PDX models and patients can further illuminate cellular and molecular pathways facilitating CTCcl formation.
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http://dx.doi.org/10.3390/jcm8111772DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6912280PMC
October 2019

Targeting the Mevalonate Pathway to Overcome Acquired Anti-HER2 Treatment Resistance in Breast Cancer.

Mol Cancer Res 2019 11 16;17(11):2318-2330. Epub 2019 Aug 16.

Lester & Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas.

Despite effective strategies, resistance in HER2 breast cancer remains a challenge. While the mevalonate pathway (MVA) is suggested to promote cell growth and survival, including in HER2 models, its potential role in resistance to HER2-targeted therapy is unknown. Parental HER2 breast cancer cells and their lapatinib-resistant and lapatinib + trastuzumab-resistant derivatives were used for this study. MVA activity was found to be increased in lapatinib-resistant and lapatinib + trastuzumab-resistant cells. Specific blockade of this pathway with lipophilic but not hydrophilic statins and with the N-bisphosphonate zoledronic acid led to apoptosis and substantial growth inhibition of R cells. Inhibition was rescued by mevalonate or the intermediate metabolites farnesyl pyrophosphate or geranylgeranyl pyrophosphate, but not cholesterol. Activated Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) and mTORC1 signaling, and their downstream target gene product Survivin, were inhibited by MVA blockade, especially in the lapatinib-resistant/lapatinib + trastuzumab-resistant models. Overexpression of constitutively active YAP rescued Survivin and phosphorylated-S6 levels, despite blockade of the MVA. These results suggest that the MVA provides alternative signaling leading to cell survival and resistance by activating YAP/TAZ-mTORC1-Survivin signaling when HER2 is blocked, suggesting novel therapeutic targets. MVA inhibitors including lipophilic statins and N-bisphosphonates may circumvent resistance to anti-HER2 therapy warranting further clinical investigation. IMPLICATIONS: The MVA was found to constitute an escape mechanism of survival and growth in HER2 breast cancer models resistant to anti-HER2 therapies. MVA inhibitors such as simvastatin and zoledronic acid are potential therapeutic agents to resensitize the tumors that depend on the MVA to progress on anti-HER2 therapies.
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http://dx.doi.org/10.1158/1541-7786.MCR-19-0756DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6825570PMC
November 2019

HER2-Enriched Subtype and ERBB2 Expression in HER2-Positive Breast Cancer Treated with Dual HER2 Blockade.

J Natl Cancer Inst 2020 01;112(1):46-54

Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX.

Background: Identification of HER2-positive breast cancers with high anti-HER2 sensitivity could help de-escalate chemotherapy. Here, we tested a clinically applicable RNA-based assay that combines ERBB2 and the HER2-enriched (HER2-E) intrinsic subtype in HER2-positive disease treated with dual HER2-blockade without chemotherapy.

Methods: A research-based PAM50 assay was applied in 422 HER2-positive tumors from five II-III clinical trials (SOLTI-PAMELA, TBCRC023, TBCRC006, PER-ELISA, EGF104090). In SOLTI-PAMELA, TBCRC023, TBCRC006, and PER-ELISA, all patients had early disease and were treated with neoadjuvant lapatinib or pertuzumab plus trastuzumab for 12-24 weeks. Primary outcome was pathological complete response (pCR). In EGF104900, 296 women with advanced disease were randomized to receive either lapatinib alone or lapatinib plus trastuzumab. Progression-free survival (PFS), overall response rate (ORR), and overall survival (OS) were evaluated.

Results: A total of 305 patients with early and 117 patients with advanced HER2-positive disease were analyzed. In early disease, HER2-E represented 83.8% and 44.7% of ERBB2-high and ERBB2-low tumors, respectively. Following lapatinib and trastuzumab, the HER2-E and ERBB2 (HER2-E/ERBB2)-high group showed a higher pCR rate compared to the rest (44.5%, 95% confidence interval [CI] = 35.4% to 53.9% vs 11.6%, 95% CI = 6.9% to 18.0%; adjusted odds ratio [OR] = 6.05, 95% CI = 3.10 to 11.80, P < .001). Similar findings were observed with neoadjuvant trastuzumab and pertuzumab (pCR rate of 66.7% in HER2-E/ERBB2-high, 95% CI = 22.3% to 95.7% vs 14.7% in others, 95% CI = 4.9% to 31.1%; adjusted OR = 11.60, 95% CI = 1.66 to 81.10, P = .01). In the advanced setting, the HER2-E/ERBB2-high group was independently associated with longer PFS (hazard ratio [HR] = 0.52, 95% CI = 0.35 to 0.79, P < .001); higher ORR (16.3%, 95% CI = 8.9% to 26.2% vs 3.7%, 95% CI = 0.8% to 10.3%, P = .02); and longer OS (HR = 0.66, 95% CI = 0.44 to 0.97, P = .01).

Conclusions: Combining HER2-E subtype and ERBB2 mRNA into a single assay identifies tumors with high responsiveness to HER2-targeted therapy. This biomarker could help de-escalate chemotherapy in approximately 40% of patients with HER2-positive breast cancer.
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http://dx.doi.org/10.1093/jnci/djz042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7850037PMC
January 2020

Circulating tumor cell investigation in breast cancer patient-derived xenograft models by automated immunofluorescence staining, image acquisition, and single cell retrieval and analysis.

BMC Cancer 2019 Mar 12;19(1):220. Epub 2019 Mar 12.

Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, TX, USA.

Background: Breast cancer patient-derived xenograft (BC-PDX) models represent a continuous and reproducible source of circulating tumor cells (CTCs) for studying their role in tumor biology and metastasis. We have previously shown the utility of BC-PDX models in the study of CTCs by immunohistochemistry (IHC) on serial paraffin sections and manual microscopic identification of cytokeratin-positive cells, a method that is both low-throughput and labor-intensive. We therefore aimed to identify and characterize CTCs from small volume mouse blood samples and examined its practical workflow in a study of BC-PDX mice treated with chemotherapy using an automated imaging platform, the AccuCyte®-CyteFinder® system.

Methods: CTC analysis was conducted using blood from non-tumor bearing SCID/Beige mice spiked with human breast cancer cells, BC-PDX-bearing mice, and BC-PDX mice treated with vehicle or chemotherapeutic agent(s). After red blood cell lysis, nucleated cells were mixed with transfer solution, processed onto microscope slides, and stained by immunofluorescence. The CyteFinder automated scanning microscope was used to identify CTCs, defined as nucleated cells that were human cytokeratin-positive, and mouse CD45-negative. Disaggregated primary BC-PDX tumors and lung metastatic nodules were processed using the same immunostaining protocol. Collective expression of breast cancer cell surface markers (EpCAM, EGFR, and HER2) using a cocktail of target-specific antibodies was assessed. CTCs and disaggregated tumor cells were individually retrieved from slides using the CytePicker® module for sequence analysis of a BC-PDX tumor-specific PIK3CA mutation.

Results: The recovery rate of human cancer cells spiked into murine blood was 83 ± 12%. CTC detection was not significantly different from the IHC method. One-third of CTCs did not stain positive for cell surface markers. A PIK3CA T1035A mutation present in a BC-PDX tumor was confirmed in isolated single CTCs and cells from dissociated metastatic nodules after whole genome amplification and sequencing. CTC evaluation could be simply implemented into a preclinical PDX therapeutic study setting with substantial improvements in workflow over the IHC method.

Conclusions: Analysis of small volume blood samples from BC-PDX-bearing mice using the AccuCyte-CyteFinder system allows investigation of the role of CTCs in tumor biology and metastasis independent of surface marker expression.
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http://dx.doi.org/10.1186/s12885-019-5382-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6419430PMC
March 2019

Neratinib in HER2-Positive Breast Cancer Patients.

Ann Pharmacother 2019 06 4;53(6):612-620. Epub 2019 Jan 4.

1 University of Houston College of Pharmacy, Houston, TX, USA.

Objective: To review the chemistry, pharmacology, pharmacokinetics, safety, and efficacy of neratinib in human epidermal growth factor receptor (HER2)+ breast cancer (BC).

Data Sources: A PubMed search was performed using the term neratinib between September 12, 2018, and November 21, 2018. References of published articles and reviews were also assessed for additional information.

Study Selection And Data Extraction: English-language preclinical and clinical studies on the chemistry, pharmacology, pharmacokinetics, safety, and efficacy of neratinib were evaluated.

Data Synthesis: Neratinib, an irreversible inhibitor of HER1, HER2, and HER4, is Food and Drug Administration approved for the extended adjuvant treatment of stage I-III HER2+ BC to follow trastuzumab-based therapy. A phase III study has demonstrated statistically significant improvement in 5-year disease-free survival rate (90.2 vs 87.7; hazard ratio = 0.73, 95% CI = 0.57-0.92, P = 0.0083). Its most common adverse effect is diarrhea, observed in more than 90% of patients. The incidence of grade 3/4 diarrhea (~40%) is reduced by half with loperamide prophylaxis, which is recommended for the first 8 weeks of neratinib therapy. Other common adverse reactions are nausea and fatigue. The patients need to be monitored for liver function tests and drug interactions with acid-reducing agents, CYP3A4 inhibitors/inducers, and P-glycoprotein substrates with narrow therapeutic window. Relevance to Patient Care and Clinical Practice: American Society of Clinical Oncology and National Comprehensive Cancer Network clinical guidelines suggest the use of neratinib for extended adjuvant therapy following 1-year trastuzumab in stage I to III HER2+ BC. Diarrhea remains a clinically significant but manageable adverse event.

Conclusion: Neratinib significantly improves treatment outcomes and has manageable toxicity in stage I to III HER2+ BC patients.
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http://dx.doi.org/10.1177/1060028018824088DOI Listing
June 2019

The oral selective oestrogen receptor degrader (SERD) AZD9496 is comparable to fulvestrant in antagonising ER and circumventing endocrine resistance.

Br J Cancer 2019 02 17;120(3):331-339. Epub 2018 Dec 17.

Lester & Sue Smith Breast Center, Baylor College of Medicine, Houston, TX, 77030, USA.

Background: The oestrogen receptor (ER) is an important therapeutic target in ER-positive (ER+) breast cancer. The selective ER degrader (SERD), fulvestrant, is effective in patients with metastatic breast cancer, but its intramuscular route of administration and low bioavailability are major clinical limitations.

Methods: Here, we studied the pharmacology of a new oral SERD, AZD9496, in a panel of in vitro and in vivo endocrine-sensitive and -resistant breast cancer models.

Results: In endocrine-sensitive models, AZD9496 inhibited cell growth and blocked ER activity in the presence or absence of oestrogen. In vivo, in the presence of oestrogen, short-term AZD9496 treatment, like fulvestrant, resulted in tumour growth inhibition and reduced expression of ER-dependent genes. AZD9496 inhibited cell growth in oestrogen deprivation-resistant and tamoxifen-resistant cell lines and xenograft models that retain ER expression. AZD9496 effectively reduced ER levels and ER-induced transcription. Expression analysis of short-term treated tumours showed that AZD9496 potently inhibited classic oestrogen-induced gene transcription, while simultaneously increasing expression of genes negatively regulated by ER, including genes potentially involved in escape pathways of endocrine resistance.

Conclusions: These data suggest that AZD9496 is a potent anti-oestrogen that antagonises and degrades ER with anti-tumour activity in both endocrine-sensitive and endocrine-resistant models.
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http://dx.doi.org/10.1038/s41416-018-0354-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6353941PMC
February 2019

Ribociclib in HR+/HER2- Advanced or Metastatic Breast Cancer Patients.

Ann Pharmacother 2019 05 7;53(5):501-509. Epub 2018 Dec 7.

3 Houston Methodist Hospital, Houston, TX, USA.

Objective: To review the chemistry, pharmacology, pharmacokinetics, safety, and efficacy of ribociclib (LEE011, Kisqali) in hormone receptor-positive/human epidermal growth factor receptor-2-negative (HR+/HER2-) metastatic breast cancer.

Data Sources: A PubMed search was performed using the terms 'Ribociclib', 'Kisqali', and 'LEE011' between May 2018 and November 2018. References of published articles and reviews were also assessed for additional information.

Study Selection And Data Extraction: English-language preclinical and clinical studies on the chemistry, pharmacology, pharmacokinetics, safety, and efficacy of ribociclib were evaluated.

Data Synthesis: Ribociclib, a cyclin-dependent kinase (CDK) 4/6 inhibitor, is Food and Drug Administration (FDA) approved in combination with endocrine therapy for treatment of HR+/HER2- advanced or metastatic breast cancer in premenopausal/perimenopausal and postmenopausal women. Three phase III trials have evaluated ribociclib in combination with endocrine therapy, including letrozole, anastrozole, tamoxifen, and fulvestrant. These studies found that ribociclib 600 mg/d, 21 days on, 7 days off, leads to a significantly greater median progression-free survival (PFS), ranging from 8 to 13 months. Ribociclib is well tolerated in elderly patients, maintains health-related quality of life, and significantly reduces pain scores. The dose-limiting toxicities found in phase I studies were neutropenia, thrombocytopenia, and QTc prolongation. Common adverse effects seen in phase III trials include neutropenia, leukopenia, nausea, diarrhea, vomiting, and fatigue. Relevance to Patient Care and Clinical Practice: Literature on the safety and efficacy of ribociclib as well as its place in therapy in comparison to other FDA-approved CDK4/6 inhibitors for breast cancer is discussed.

Conclusions: Ribociclib, when added to endocrine therapy, significantly improves PFS and has manageable toxicity in premenopausal/perimenopausal and postmenopausal women with HR+/HER2- advanced breast cancer.
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http://dx.doi.org/10.1177/1060028018817904DOI Listing
May 2019

Cyclin E1 and Rb modulation as common events at time of resistance to palbociclib in hormone receptor-positive breast cancer.

NPJ Breast Cancer 2018 28;4:38. Epub 2018 Nov 28.

1"Sandro Pitigliani" Translational Research Unit, Hospital of Prato, Prato, Italy.

CDK4/6 inhibitors represent a new treatment standard for hormone receptor-positive (HR+), HER2-negative advanced breast cancer (BC) patients. Although efficacious, resistance to these agents is universal. Here, we profiled a large panel of HR+ BC cell lines with conditioned resistance to the CDK4/6 inhibitor palbociclib, and analyzed cell cycle-related markers by gene expression profiles (GEP) and western blot (WB). GEP showed high molecular heterogeneity among the models, with E2F targets being significantly enriched both during treatment and at the time of resistance. By both WB and GEP, a common molecular feature at the time of palbociclib resistance was the concomitant overexpression of cyclin E1 and down-regulation of Rb. was the only significantly up-regulated gene among E2F targets at resistance with genomic amplification being observed in two resistant models. Rb was downregulated in all resistant models; a reduction of copy number was observed in three resistant cell lines. In silico analyses showed that ratio correlated with palbociclib IC50 in different datasets of both breast and non-breast cancer cell lines, performing better than or taken separately. Finally, the ratio was shown to be an adverse prognostic factor in patients with ER+ BC and to be able to discriminate palbociclib-sensitive versus resistant among patients enrolled in the NeoPalAna trial, a neoadjuvant trial testing palbociclib, performing better than or alone. Our data suggest that the ratio may be a viable biomarker of palbociclib resistance, warranting further clinical validation.
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http://dx.doi.org/10.1038/s41523-018-0092-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6261939PMC
November 2018

GPCRs profiling and identification of GPR110 as a potential new target in HER2+ breast cancer.

Breast Cancer Res Treat 2018 Jul 24;170(2):279-292. Epub 2018 Mar 24.

Department of Pharmacy Practice and Translational Research, University of Houston, 4849 Calhoun St, Houston, TX, 77204, USA.

Purpose: G protein-coupled receptors (GPCRs) represent the largest family of druggable targets in human genome. Although several GPCRs can cross-talk with the human epidermal growth factor receptors (HERs), the expression and function of most GPCRs remain unknown in HER2+ breast cancer (BC). In this study, we aimed to evaluate gene expression of GPCRs in tumorigenic or anti-HER2 drug-resistant cells and to understand the potential role of candidate GPCRs in HER2+ BC.

Methods: Gene expression of 352 GPCRs was profiled in Aldeflur+ tumorigenic versus Aldeflur- population and anti-HER2 therapy-resistant derivatives versus parental cells of HER2+ BT474 cells. The GPCR candidates were confirmed in 7 additional HER2+ BC cell line models and publicly available patient dataset. Anchorage-dependent and anchorage-independent cell growth, mammosphere formation, and migration/invasion were evaluated upon GPR110 knockdown by siRNA in BT474 and SKBR3 parental and lapatinib+ trastuzumab-resistant (LTR) cells.

Results: Adhesion and class A GPCRs were overexpressed in Aldeflur+ and anti-HER2 therapy-resistant population of BT474 cells, respectively. GPR110 was the only GPCR overexpressed in Aldeflur+ and anti-HER2 therapy-resistant population in BT474, SKBR3, HCC1569, MDA-MB-361, AU565, and/or HCC202 cells and in HER2+ BC subtype in patient tumors. Using BT474 and SKBR3 parental and LTR cells, we found that GPR110 knockdown significantly reduced anchorage-dependent/independent cell growth as well as migration/invasion of parental and LTR cells and mammosphere formation in LTR derivatives and not in parental cells.

Conclusion: Our data suggest a potential role of GPR110 in tumorigenicity and in tumor cell dissemination in HER2+ BC.
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http://dx.doi.org/10.1007/s10549-018-4751-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6110614PMC
July 2018

Combined effect of obesity and diabetes on early breast cancer outcome: a prospective observational study.

Oncotarget 2017 Dec 5;8(70):115709-115717. Epub 2017 Dec 5.

Department of Clinical Medicine and Surgery, Oncology Division, University of Naples Federico II, Naples, Italy.

Background: Previous studies suggested that obesity and diabetes were correlated with breast cancer outcome. The aim of the present study was to investigate the prognostic effect of obesity and diabetes on the outcome of early breast cancer patients.

Materials And Methods: Overall, 841 early breast cancer patients were prospectively enrolled between January 2009 and December 2013. Study population was divided into four groups: (1) patients without obesity or diabetes; (2) patients with only diabetes; (3) patients with only obesity; and (4) patients with both diabetes and obesity. Categorical variables were analyzed by the chi-square test and survival data by the log-rank test.

Results: At diagnosis, obese and diabetic patients were more likely to be older ( < 0.0001) and post-menopausal ( < 0.0001) and to have a tumor larger than 2 cm ( < 0.0001) than patients in groups 1-3. At univariate analyses, obese and diabetic patients had a worse disease-free survival ( = 0.01) and overall survival ( = 0.001) than did patients without obesity and diabetes. At multivariate analyses, the co-presence of obesity and diabetes was an independent prognostic factor for disease-free survival (hazard ratio=2.62, 95% CI 1.23-5.60) but not for overall survival.

Conclusions: At diagnosis, patients with obesity and diabetes were older, had larger tumors and a worse outcome compared to patients without obesity or diabetes. These data suggest that metabolic health influences the prognosis of patients affected by early breast cancer.
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http://dx.doi.org/10.18632/oncotarget.22977DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5777806PMC
December 2017

Luminal-like HER2-negative stage IA breast cancer: a multicenter retrospective study on long-term outcome with propensity score analysis.

Oncotarget 2017 12 24;8(68):112816-112824. Epub 2017 Nov 24.

Clinical Medicine and Surgery Department, University of Naples Federico II, 80131 Naples, Italy.

The benefit of adding chemotherapy (CT) to adjuvant hormone therapy (HT) in stage IA luminal-like HER2-negative breast cancer (BC) is unclear. We retrospectively evaluated predictive factors and clinical outcome of 1,222 patients from 4 oncologic centers. Three hundred and eighty patients received CT and HT (CT-cohort) and 842 received HT alone (HT-cohort). Disease-free survival (DFS) and overall survival (OS) were evaluated with univariate and multivariate analyses. We also applied the propensity score methodology. Compared with the HT-cohort, patients in the CT-cohort were more likely to be younger, have larger tumors of a higher histological grade that were Ki67-positive, and lower estrogen and progesterone receptor expression. At univariate analysis, a higher histological grade and Ki67 were significantly associated to a lower DFS. At multivariable analysis, only histological grade was predictive of DFS. The CT-cohort had a worse outcome than the HT-cohort in terms of DFS and OS, but differences disappeared when matched according to propensity score. In summary, patients with stage IA luminal-like BC had an excellent prognosis, however relapse and mortality were higher in the CT-cohort than in the HT-cohort. Longer use of adjuvant HT or other therapeutic strategies may be needed to improve outcome.
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http://dx.doi.org/10.18632/oncotarget.22643DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5762553PMC
December 2017

Tamoxifen Resistance in Breast Cancer Is Regulated by the EZH2-ERα-GREB1 Transcriptional Axis.

Cancer Res 2018 02 6;78(3):671-684. Epub 2017 Dec 6.

Department of Molecular Medicine, University of Texas Health Science Center, San Antonio, Texas.

Resistance to cancer treatment can be driven by epigenetic reprogramming of specific transcriptomes in favor of the refractory phenotypes. Here we discover that tamoxifen resistance in breast cancer is driven by a regulatory axis consisting of a master transcription factor, its cofactor, and an epigenetic regulator. The oncogenic histone methyltransferase EZH2 conferred tamoxifen resistance by silencing the expression of the estrogen receptor α (ERα) cofactor GREB1. In clinical specimens, induction of DNA methylation of a particular CpG-enriched region at the promoter negatively correlated with levels and cell sensitivity to endocrine agents. GREB1 also ensured proper cellular reactions to different ligands by recruiting distinct sets of ERα cofactors to -regulatory elements, which explains the contradictory biological effects of GREB1 on breast cancer cell growth in response to estrogen or antiestrogen. In refractory cells, EZH2-dependent repression of GREB1 triggered chromatin reallocation of ERα coregulators, converting the antiestrogen into an agonist. In clinical specimens from patients receiving adjuvant tamoxifen treatment, expression levels of EZH2 and GREB1 were correlated negatively, and taken together better predicted patient responses to endocrine therapy. Overall, our work suggests a new strategy to overcome endocrine resistance in metastatic breast cancer by targeting a particular epigenetic program. This study suggests a new strategy to overcome endocrine resistance in metastatic breast cancer by targeting a particular epigenetic program defined within. .
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http://dx.doi.org/10.1158/0008-5472.CAN-17-1327DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5967248PMC
February 2018

PTK6 regulates growth and survival of endocrine therapy-resistant ER+ breast cancer cells.

NPJ Breast Cancer 2017 17;3:45. Epub 2017 Nov 17.

Division of Hematology and Medical Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, 1468 Madison Ave, New York, NY USA.

The non-receptor tyrosine kinase, PTK6/BRK, is highly expressed in multiple tumor types, including prostate, ovarian, and breast cancers, and regulates oncogenic phenotypes such as proliferation, migration, and survival. PTK6 inhibition also overcomes targeted therapy resistance of HER2+ breast cancer. Although PTK6 is highly expressed in ER+ Luminal breast cancers, the role of PTK6 in this subtype has not been elucidated. In this study, we investigated the functions of PTK6 in ER+ Luminal breast cancer cells, including those that are relatively resistant to estrogen deprivation or targeted endocrine therapies used in the treatment of ER+ cancers. Enhanced expression of PTK6 in ER+ breast cancer cells enhances growth of ER+ breast cancer cells, including tamoxifen-treated cells. Downregulation of PTK6 in ER+ breast cancer cells, including those resistant to tamoxifen, fulvestrant, and estrogen deprivation, induces apoptosis, as evidenced by increased levels of cleaved PARP, and an increase in the AnnexinV+ population. PTK6 downregulation impairs growth of these cells in 3D Matrigel cultures, and virtually abrogates primary tumor growth of both tamoxifen-sensitive and resistant MCF-7 xenografts. Finally, we show that p38 MAPK activation is critical for PTK6 downregulation-induced apoptosis, a mechanism that we previously reported for survival of HER2+ breast cancer cells, highlighting conserved mechanisms of survival regulation by PTK6 across breast cancer subtypes. In conclusion, our studies elucidate critical functions of PTK6 in ER+ Luminal breast cancers and support PTK6 as an attractive therapeutic target for ER+ breast cancers.
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http://dx.doi.org/10.1038/s41523-017-0047-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5694002PMC
November 2017

Low PTEN levels and PIK3CA mutations predict resistance to neoadjuvant lapatinib and trastuzumab without chemotherapy in patients with HER2 over-expressing breast cancer.

Breast Cancer Res Treat 2018 02 7;167(3):731-740. Epub 2017 Nov 7.

Dan L. Duncan Comprehensive Cancer Center at Baylor College of Medicine and Baylor St. Luke's Medical Center, BCM 600, One Baylor Plaza, Houston, TX, 77030, USA.

Purpose: Aberrant activation of the PI3K pathway has been implicated in resistance to HER2-targeted therapy, but results of clinical trials are confounded by the co-administration of chemotherapy. We investigated the effect of perturbations of this pathway in breast cancers from patients treated with neoadjuvant anti-HER2-targeted therapy without chemotherapy.

Patients And Methods: Baseline tumor samples from patients with HER2-positive breast cancer enrolled in TBCRC006 (NCT00548184), a 12-week neoadjuvant clinical trial with lapatinib plus trastuzumab [plus endocrine therapy for estrogen receptor (ER)-positive tumors], were assessed for PTEN status by immunohistochemistry and PIK3CA mutations by sequencing. Results were correlated with pathologic complete response (pCR).

Results: Of 64 evaluable patients, PTEN immunohistochemistry and PIK3CA mutation analysis were performed for 59 and 46 patients, respectively. PTEN status (dichotomized by H-score median) was correlated with pCR (32% in high PTEN vs. 9% in low PTEN, p = 0.04). PIK3CA mutations were identified in 14/46 tumors at baseline (30%) and did not correlate with ER or PTEN status. One patient whose tumor harbored a PIK3CA mutation achieved pCR (p = 0.14). When considered together (43 cases), 1/25 cases (4%) with a PIK3CA mutation and/or low PTEN expression levels had a pCR compared to 7/18 cases (39%) with wild-type PI3KCA and high PTEN expression levels (p = 0.006).

Conclusion: PI3K pathway activation is associated with resistance to lapatinib and trastuzumab in breast cancers, without chemotherapy. Further studies are warranted to investigate how to use these biomarkers to identify upfront patients who may respond to anti-HER2 alone, without chemotherapy.
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http://dx.doi.org/10.1007/s10549-017-4533-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5821069PMC
February 2018

De-escalation of treatment in HER2-positive breast cancer: Determinants of response and mechanisms of resistance.

Breast 2017 Aug 4;34 Suppl 1:S19-S26. Epub 2017 Jul 4.

Lester & Sue Smith Breast Center, Baylor College of Medicine, Houston, TX, USA; Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA; Department of Medicine, Baylor College of Medicine, Houston, TX, USA; Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA. Electronic address:

Overexpression and/or gene amplification of HER2, a crucial member of the HER family of four receptors, occur in about 15-20% of breast cancers and define an aggressive subtype of the disease. Activated HER homo and heterodimers govern a complex and redundant downstream signaling network that regulates cell survival and metastasis. Despite treatment with effective HER2-targeted therapies, many HER2-positive tumors fail to respond, or initially respond but eventually develop resistance. One of the upfront reasons for this treatment failure is failure to accurately select the tumors that are truly dependent on HER2 for survival and so would benefit the most from HER2-targeted therapy. In these truly HER2-addicted tumors (i.e. physiologically dependent), resistance could be the result of an incomplete inhibition of signaling at the HER receptor layer. In this regard, preclinical and clinical studies have documented the superiority of combination anti-HER2 therapy over single agent therapy to achieve a more comprehensive inhibition of the various HER receptor dimers. HER2 can be further activated or reactivated by mutations or other alterations in HER2 itself, or in other HER family members. Even when a complete and sustained HER inhibition is achieved, resistance to anti-HER therapy can arise by other somewhat dominant mechanisms, including preexisting or emerging alternative signaling pathways such as the estrogen receptor, deregulated downstream signaling components, especially of the PI3K pathway, and the tumor immune microenvironment. Most of the clinical trials that have investigated the efficacy of anti-HER2 therapies took place in the background of aggressive chemotherapy regimens, thus confounding the identification of key factors of resistance to the anti-HER2 treatments. Recent studies, however, have suggested that some HER2-amplified tumors may benefit from anti-HER2 therapy combined with only a single chemotherapy agent or in the absence of any chemotherapy. This de-escalation approach, a promising therapeutic strategy, is currently being explored in the clinic. In this review, we summarize the major molecular determinants that play a crucial role in influencing tumor response and resistance to HER2-targeted therapy, and discuss the growing need for patient stratification in order to facilitate the development of de-escalation strategies using HER2-targeted therapy alone with no chemotherapy.
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http://dx.doi.org/10.1016/j.breast.2017.06.022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6050048PMC
August 2017

Pretreatment Serum Concentration of Vitamin D and Breast Cancer Characteristics: A Prospective Observational Mediterranean Study.

Clin Breast Cancer 2017 11 19;17(7):559-563. Epub 2017 May 19.

Oncology Division, Department of Clinical Medicine and Surgery, University of Naples "Federico II", Naples, Italy.

Background: Recent studies of the correlation between breast cancer (BC) and vitamin D yielded contrasting results. Although preclinical and clinical evidence has implicated vitamin D in BC prevention and outcome, little is known about the link between vitamin D and specific BC histologically defined subtypes. In the attempt to clarify this association we correlated vitamin D levels with BC characteristics.

Patients And Methods: We enrolled 220 pre- and postmenopausal women with early BC in this prospective observational trial. Data on the patients' clinical and specific BC pathological characteristics were collected and related to vitamin D levels, stratified in deficient (< 20 ng/mL), insufficient (20-30 ng/mL), and sufficient (> 30 ng/mL). BC subtypes were defined according to the 14th St Gallen Breast Cancer Conference.

Results: Deficient vitamin D levels were correlated with Grade 3 (P = .015) and node-positive (P = .043) BC, and with a higher body mass index (P = .017). Insufficient vitamin D levels were associated with estrogen receptor expression in the primary tumor (P = .033). Vitamin D levels were unrelated to the histological molecular subtypes of BC.

Conclusion: Deficient vitamin D levels were correlated with more aggressive disease, namely, node-positive high grade BC, and with obesity. Should our findings be confirmed in larger prospective studies, nutritional programs designed to reduce body weight, and vitamin D supplementation might be considered a BC prevention strategy.
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http://dx.doi.org/10.1016/j.clbc.2017.05.007DOI Listing
November 2017

Embryonic transcription factor SOX9 drives breast cancer endocrine resistance.

Proc Natl Acad Sci U S A 2017 05 15;114(22):E4482-E4491. Epub 2017 May 15.

Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA 02215;

The estrogen receptor (ER) drives the growth of most luminal breast cancers and is the primary target of endocrine therapy. Although ER blockade with drugs such as tamoxifen is very effective, a major clinical limitation is the development of endocrine resistance especially in the setting of metastatic disease. Preclinical and clinical observations suggest that even following the development of endocrine resistance, ER signaling continues to exert a pivotal role in tumor progression in the majority of cases. Through the analysis of the ER cistrome in tamoxifen-resistant breast cancer cells, we have uncovered a role for an RUNX2-ER complex that stimulates the transcription of a set of genes, including most notably the stem cell factor SOX9, that promote proliferation and a metastatic phenotype. We show that up-regulation of SOX9 is sufficient to cause relative endocrine resistance. The gain of SOX9 as an ER-regulated gene associated with tamoxifen resistance was validated in a unique set of clinical samples supporting the need for the development of improved ER antagonists.
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http://dx.doi.org/10.1073/pnas.1620993114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5465894PMC
May 2017