Publications by authors named "Susan G Hilsenbeck"

167 Publications

Therapeutic Targeting of Nemo-like Kinase in Primary and Acquired Endocrine-resistant Breast Cancer.

Clin Cancer Res 2021 Feb 4. Epub 2021 Feb 4.

UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania.

Purpose: Endocrine resistance remains a major clinical challenge in estrogen receptor (ER)-positive breast cancer. Despite the encouraging results from clinical trials for the drugs targeting known survival signaling, relapse is still inevitable. There is an unmet need to discover new drug targets in the unknown escape pathways. Here, we report Nemo-like kinase (NLK) as a new actionable kinase target that endows previously uncharacterized survival signaling in endocrine-resistant breast cancer.

Experimental Design: The effects of NLK inhibition on the viability of endocrine-resistant breast cancer cell lines were examined by MTS assay. The effect of VX-702 on NLK activity was verified by kinase assay. The modulation of ER and its coactivator, SRC-3, by NLK was examined by immunoprecipitation, kinase assay, luciferase assay, and RNA sequencing. The therapeutic effects of VX-702 and everolimus were tested on cell line- and patient-derived xenograft (PDX) tumor models.

Results: NLK overexpression endows reduced endocrine responsiveness and is associated with worse outcome of patients treated with tamoxifen. Mechanistically, NLK may function, at least in part, via enhancing the phosphorylation of ERα and its key coactivator, SRC-3, to modulate ERα transcriptional activity. Through interrogation of a kinase profiling database, we uncovered and verified a highly selective dual p38/NLK inhibitor, VX-702. Coadministration of VX-702 with the mTOR inhibitor, everolimus, demonstrated a significant therapeutic effect in cell line-derived xenograft and PDX tumor models of acquired or endocrine resistance.

Conclusions: Together, this study reveals the potential of therapeutic modulation of NLK for the management of the endocrine-resistant breast cancers with active NLK signaling.
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http://dx.doi.org/10.1158/1078-0432.CCR-20-2961DOI Listing
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

Hormonal modulation of ESR1 mutant metastasis.

Oncogene 2021 Feb 15;40(5):997-1011. Epub 2020 Dec 15.

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

Estrogen receptor alpha gene (ESR1) mutations occur frequently in ER-positive metastatic breast cancer, and confer clinical resistance to aromatase inhibitors. Expression of the ESR1 Y537S mutation induced an epithelial-mesenchymal transition (EMT) with cells exhibiting enhanced migration and invasion potential in vitro. When small subpopulations of Y537S ESR1 mutant cells were injected along with WT parental cells, tumor growth was enhanced with mutant cells becoming the predominant population in distant metastases. Y537S mutant primary xenograft tumors were resistant to the antiestrogen tamoxifen (Tam) as well as to estradiol (E) withdrawal. Y537S ESR1 mutant primary tumors metastasized efficiently in the absence of E; however, Tam treatment significantly inhibited metastasis to distant sites. We identified a nine-gene expression signature, which predicted clinical outcomes of ER-positive breast cancer patients, as well as breast cancer metastasis to the lung. Androgen receptor (AR) protein levels were increased in mutant models, and the AR agonist dihydrotestosterone significantly inhibited estrogen-regulated gene expression, EMT, and distant metastasis in vivo, suggesting that AR may play a role in distant metastatic progression of ESR1 mutant tumors.
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http://dx.doi.org/10.1038/s41388-020-01563-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8020875PMC
February 2021

Mailed self-sample HPV testing kits to improve cervical cancer screening in a safety net health system: protocol for a hybrid effectiveness-implementation randomized controlled trial.

Trials 2020 Oct 21;21(1):872. Epub 2020 Oct 21.

Center for Epidemiology and Population Health, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, MS: 305, Houston, TX, 77030, USA.

Background: Almost 20% of U.S. women remain at risk for cervical cancer due to their inability or unwillingness to participate in periodic clinic-based screening. Self-sampling has been shown to be an effective strategy for screening women for high-risk human papillomavirus (HR-HPV) infection in specific contexts. However, its effectiveness among medically underserved women in safety net health systems has not been evaluated. Furthermore, it is also unclear whether implementation strategies such as patient navigation can be used to improve the success of self-sample screening programs by addressing patient-level barriers to participation.

Methods/design: The Prospective Evaluation of Self-Testing to Increase Screening (PRESTIS) trial is a hybrid type 2 effectiveness-implementation pragmatic randomized controlled trial of mailed self-sample HPV testing. The aim is to assess the effectiveness of mailed self-sample HPV testing kits to improve cervical cancer screening participation among patients in a safety net health system who are overdue for clinic-based screening, while simultaneously assessing patient navigation as an implementation strategy. Its setting is a large, urban safety net health system that serves a predominantly racial/ethnic minority patient population. The trial targets recruitment of 2268 participants randomized to telephone recall (enhanced usual care, n = 756), telephone recall with mailed self-sample HPV testing kit (intervention, n = 756), or telephone recall with mailed self-sample HPV testing kit and patient navigation (intervention + implementation strategy, n = 756). The primary effectiveness outcome is completion of primary screening, defined as completion and return of mailed self-sample kit or completion of a clinic-based Pap test. Secondary effectiveness outcomes are predictors of screening and attendance for clinical follow-up among women with a positive screening test. Implementation outcomes are reach, acceptability, fidelity, adaptations, and cost-effectiveness.

Discussion: Hybrid designs are needed to evaluate the clinical effectiveness of self-sample HPV testing in specific populations and settings, while incorporating and evaluating methods to optimize its real-world implementation. The current manuscript describes the rationale and design of a hybrid type 2 trial of self-sample HPV testing in a safety net health system. Trial findings are expected to provide meaningful data to inform screening strategies to ultimately realize the global goal of eliminating cervical cancer.

Trial Registration: ClinicalTrials.gov NCT03898167 . Registered on 01 April 2019.

Trial Status: Study start data: February 13, 2020. Recruitment status: Enrolling by invitation. Estimated primary completion date: February 15, 2023. Estimated study completion date: May 31, 2024. Protocol version 1.6 (February 25, 2020).
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http://dx.doi.org/10.1186/s13063-020-04790-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7580009PMC
October 2020

Model-Assisted Designs for Early-Phase Clinical Trials: Simplicity Meets Superiority.

JCO Precis Oncol 2019 24;3. Epub 2019 Oct 24.

Smith Breast Center, Baylor College of Medicine, Houston, TX.

Drug development enterprise is struggling because of prohibitively high costs and slow progress. There is urgent need for adoption of novel adaptive designs to improve the efficiency and success of clinical trials. A major barrier is that many conventional designs are inadequate for modern drug development, yet most novel adaptive designs are difficult to understand, require complicated statistical modeling, demand complex computation, and need expensive infrastructure for implementation. The objective of this article is to introduce and review a class of novel adaptive designs, known as model-assisted designs, to remove this barrier and increase the use of novel adaptive designs. Model-assisted designs enjoy superior performance comparable to more complicated, model-based adaptive designs, but their decision rule can be pretabulated and included in the protocol-thus implemented as simply as the conventional designs. We review state-of-the-art model-assisted designs for phase I clinical trials for single-agent, drug-combination and late-onset toxicity scenarios. We also briefly introduce model-assisted designs for phase II trials to handle binary, coprimary endpoints and delayed response. Freely available user-friendly software and trial examples (trialdesign.org) facilitate the adoption of model-assisted designs.
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http://dx.doi.org/10.1200/PO.19.00032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7446379PMC
October 2019

BCL9/STAT3 regulation of transcriptional enhancer networks promote DCIS progression.

NPJ Breast Cancer 2020 24;6:12. Epub 2020 Apr 24.

13Department of Pathology and Laboratory Medicine, MS 3045, The University of Kansas Medical Center, Kansas City, KS 66160 USA.

The molecular processes by which some human ductal carcinoma in situ (DCIS) lesions advance to the more aggressive form, while others remain indolent, are largely unknown. Experiments utilizing a patient-derived (PDX) DCIS Mouse INtraDuctal (MIND) animal model combined with ChIP-exo and RNA sequencing revealed that the formation of protein complexes between B Cell Lymphoma-9 (BCL9), phosphoserine 727 STAT3 (PS-727-STAT3) and non-STAT3 transcription factors on chromatin enhancers lead to subsequent transcription of key drivers of DCIS malignancy. Downregulation of two such targets, integrin β3 and its associated metalloproteinase, MMP16, resulted in a significant inhibition of DCIS invasive progression. Finally, in vivo targeting of BCL9, using rosemary extract, resulted in significant inhibition of DCIS malignancy in both cell line and PDX DCIS MIND animal models. As such, our studies provide compelling evidence for future testing of rosemary extract as a chemopreventive agent in breast cancer.
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http://dx.doi.org/10.1038/s41523-020-0157-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7181646PMC
April 2020

Neurofibromin Is an Estrogen Receptor-α Transcriptional Co-repressor in Breast Cancer.

Cancer Cell 2020 03 5;37(3):387-402.e7. Epub 2020 Mar 5.

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

We report that neurofibromin, a tumor suppressor and Ras-GAP (GTPase-activating protein), is also an estrogen receptor-α (ER) transcriptional co-repressor through leucine/isoleucine-rich motifs that are functionally independent of GAP activity. GAP activity, in turn, does not affect ER binding. Consequently, neurofibromin depletion causes estradiol hypersensitivity and tamoxifen agonism, explaining the poor prognosis associated with neurofibromin loss in endocrine therapy-treated ER breast cancer. Neurofibromin-deficient ER breast cancer cells initially retain sensitivity to selective ER degraders (SERDs). However, Ras activation does play a role in acquired SERD resistance, which can be reversed upon MEK inhibitor addition, and SERD/MEK inhibitor combinations induce tumor regression. Thus, neurofibromin is a dual repressor for both Ras and ER signaling, and co-targeting may treat neurofibromin-deficient ER breast tumors.
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http://dx.doi.org/10.1016/j.ccell.2020.02.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7286719PMC
March 2020

The Signaling Pathways Project, an integrated 'omics knowledgebase for mammalian cellular signaling pathways.

Sci Data 2019 10 31;6(1):252. Epub 2019 Oct 31.

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

Mining of integrated public transcriptomic and ChIP-Seq (cistromic) datasets can illuminate functions of mammalian cellular signaling pathways not yet explored in the research literature. Here, we designed a web knowledgebase, the Signaling Pathways Project (SPP), which incorporates community classifications of signaling pathway nodes (receptors, enzymes, transcription factors and co-nodes) and their cognate bioactive small molecules. We then mapped over 10,000 public transcriptomic or cistromic experiments to their pathway node or biosample of study. To enable prediction of pathway node-gene target transcriptional regulatory relationships through SPP, we generated consensus 'omics signatures, or consensomes, which ranked genes based on measures of their significant differential expression or promoter occupancy across transcriptomic or cistromic experiments mapped to a specific node family. Consensomes were validated using alignment with canonical literature knowledge, gene target-level integration of transcriptomic and cistromic data points, and in bench experiments confirming previously uncharacterized node-gene target regulatory relationships. To expose the SPP knowledgebase to researchers, a web browser interface was designed that accommodates numerous routine data mining strategies. SPP is freely accessible at https://www.signalingpathways.org .
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http://dx.doi.org/10.1038/s41597-019-0193-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6823428PMC
October 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

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

Association Between Birth Defects and Cancer Risk Among Children and Adolescents in a Population-Based Assessment of 10 Million Live Births.

JAMA Oncol 2019 Jun 20. Epub 2019 Jun 20.

Department of Pediatrics, Baylor College of Medicine, Houston, Texas.

Importance: Birth defects affect approximately 1 in 33 children. Some birth defects are known to be strongly associated with childhood cancer (eg, trisomy 21 and acute leukemia). However, comprehensive evaluations of childhood cancer risk in those with birth defects have been limited in previous studies by insufficient sample sizes.

Objectives: To identify specific birth defect-childhood cancer (BD-CC) associations and characterize cancer risk in children by increasing number of nonchromosomal birth defects.

Design, Setting, And Participants: This multistate, population-based registry linkage study pooled statewide data on births, birth defects, and cancer from Texas, Arkansas, Michigan, and North Carolina on 10 181 074 children born from January 1, 1992, to December 31, 2013. Children were followed up to 18 years of age for a diagnosis of cancer. Data were retrieved between September 26, 2016, and September 21, 2017, and data analysis was performed from September 2, 2017, to March 21, 2019.

Exposures: Birth defects diagnoses (chromosomal anomalies and nonchromosomal birth defects) recorded by statewide, population-based birth defects registries.

Main Outcomes And Measures: Cancer diagnosis before age 18 years, as recorded in state cancer registries. Cox regression models were used to generate hazard ratios (HRs) and 95% CIs to evaluate BD-CC associations and the association between number of nonchromosomal defects and cancer risk.

Results: Compared with children without any birth defects (n = 10 181 074), children with chromosomal anomalies (n = 539 567) were 11.6 (95% CI, 10.4-12.9) times more likely to be diagnosed with cancer, whereas children with nonchromosomal birth defects (n = 2123) were 2.5 (95% CI, 2.4-2.6) times more likely to be diagnosed with cancer before 18 years of age. An increasing number of nonchromosomal birth defects was associated with a corresponding increase in the risk of cancer. Children with 4 or more major birth defects were 5.9 (95% CI, 5.4-6.5) times more likely to be diagnosed with cancer compared with those without a birth defect. In the analysis of 72 specific BD-CC patterns, 40 HRs were statistically significant (adjusted P < .05) after accounting for multiple comparisons. Cancers most frequently associated with nonchromosomal defects were hepatoblastoma and neuroblastoma.

Conclusions And Relevance: Several significant and novel associations were observed between specific birth defects and cancers. Among children with nonchromosomal birth defects, the number of major birth defects diagnosed was significantly and directly associated with cancer risk. These findings could inform clinical treatment for children with birth defects and may elucidate mechanisms that lead to these complex outcomes.
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http://dx.doi.org/10.1001/jamaoncol.2019.1215DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6587148PMC
June 2019

Randomized controlled trial of high-dose versus standard-dose vitamin D3 for prevention of aromatase inhibitor-induced arthralgia.

Breast Cancer Res Treat 2019 Sep 19;177(2):427-435. Epub 2019 Jun 19.

Baylor College of Medicine, 6445 Main Street, OPC 24-346, Houston, TX, 77030, USA.

Purpose: Half of hormone receptor-positive (HR+) breast cancer patients will develop joint pain, termed aromatase inhibitor-induced arthralgia (AIA), while taking aromatase inhibitor therapy. Though there is no universally accepted effective treatment for AIA, there has been some evidence to support high-dose vitamin D as a treatment.

Methods: We randomized post-menopausal women who were beginning adjuvant AI therapy to receive standard-dose vitamin D3 (800 IU daily for 52 weeks), or high-dose vitamin D3 (50,000 IU weekly for 12 weeks, followed by 2000 IU daily for 40 weeks). The primary end point was development of AIA. The trial was designed to enroll 184 patients. This futility analysis was performed after 93 patients were enrolled.

Results: The high-dose vitamin D regimen was effective in raising serum vitamin D levels, but there was no significant difference in development of AIA between the two arms. In the high-dose arm, 25 patients (54%) developed AIA, compared to 27 patients (57%) in the standard-dose arm. The planned futility analysis was positive; thus, the study was terminated. Neither baseline vitamin D nor 12-week vitamin D level was predictive of AIA development.

Conclusion: Although vitamin D levels were increased in the high-dose arm, there was no significant signal for benefit of high-dose vitamin D supplementation for AIA prevention in this unblinded trial. This study, along with several others, implies that vitamin D likely does not play a significant role in AIA for the majority of patients.
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http://dx.doi.org/10.1007/s10549-019-05319-4DOI Listing
September 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

Bacteria-to-Human Protein Networks Reveal Origins of Endogenous DNA Damage.

Cell 2019 01;176(1-2):127-143.e24

Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX 77030, USA; Systems, Synthetic and Physical Biology Program, Rice University, Houston, TX 77030, USA. Electronic address:

DNA damage provokes mutations and cancer and results from external carcinogens or endogenous cellular processes. However, the intrinsic instigators of endogenous DNA damage are poorly understood. Here, we identify proteins that promote endogenous DNA damage when overproduced: the DNA "damage-up" proteins (DDPs). We discover a large network of DDPs in Escherichia coli and deconvolute them into six function clusters, demonstrating DDP mechanisms in three: reactive oxygen increase by transmembrane transporters, chromosome loss by replisome binding, and replication stalling by transcription factors. Their 284 human homologs are over-represented among known cancer drivers, and their RNAs in tumors predict heavy mutagenesis and a poor prognosis. Half of the tested human homologs promote DNA damage and mutation when overproduced in human cells, with DNA damage-elevating mechanisms like those in E. coli. Our work identifies networks of DDPs that provoke endogenous DNA damage and may reveal DNA damage-associated functions of many human known and newly implicated cancer-promoting proteins.
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http://dx.doi.org/10.1016/j.cell.2018.12.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6344048PMC
January 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

Hypothyroidism after craniospinal irradiation with proton or photon therapy in patients with medulloblastoma.

Pediatr Hematol Oncol 2018 May 11;35(4):257-267. Epub 2018 Dec 11.

b Texas Children's Cancer and Hematology Centers , Houston , Texas , USA.

Background: Craniospinal irradiation (CSI) often results in endocrine deficiencies in children with medulloblastoma due to irradiation of the hypothalamic-pituitary axis (HPA) or the thyroid gland. CSI with Proton radiation therapy (PRT) has the potential to decrease the risk of hypothyroidism by reduction in radiation dose to these organs. This study compares the risk for hypothyroidism in patients with medulloblastoma treated with Photon radiation therapy (XRT) or PRT.

Methods: The records of patients with medulloblastoma diagnosed at a single institution between 1997 and 2014 who received CSI were, retrospectively, reviewed. Ninety-five patients (54 XRT and 41 PRT) who had baseline and yearly follow-up thyroid studies were included. We used interval censored Cox regression to calculate hazard ratios of developing any, primary, and central hypothyroidism.

Results: With a median time to last thyroid studies post radiation of 3.8 years in PRT and 9.6 years in XRT, 33/95 (34.7%) patients developed hypothyroidism (median time to hypothyroidism: 2.6 years). Hypothyroidism developed in 25/54 (46.3%) who received XRT vs. 8/41 (19%) in the PRT group (HR =1.85, p = .14). Primary hypothyroidism developed in 15/95 (15.8%) patients: 12/54 (22.2%) after XRT and 3/41 (7.3%) after PRT (HR =2.1, p = .27). Central hypothyroidism developed in 17/95 (18.0%) patients: 13/54 (24.0%) after XRT and 4/41 (9.8%) after PRT (HR =2.16, p = .18).

Conclusions: The use of PRT in patients with medulloblastoma was associated with numerically lower but not significantly lower risk of hypothyroidism. Further studies including larger numbers and longer follow up must be performed to assess whether lower radiation doses achieved with PRT show statistically significant differences.
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http://dx.doi.org/10.1080/08880018.2018.1471111DOI Listing
May 2018

A prospective study of a simple algorithm to individually dose high-dose methotrexate for children with leukemia at risk for methotrexate toxicities.

Cancer Chemother Pharmacol 2019 02 28;83(2):349-360. Epub 2018 Nov 28.

Division of Pediatric Hematology and Oncology, Department of Pediatrics, Baylor College of Medicine, 6701 Fannin Street, MWT Suite 1510.00, Houston, TX, 77030, USA.

Purpose: High-dose methotrexate (HDMTX) is critical to the successful treatment of pediatric acute lymphoblastic leukemia (ALL) but can cause significant toxicities. This study prospectively evaluated the effectiveness of a fixed algorithm which requires no real-time pharmacokinetic modeling and no previous patient exposure to HDMTX, to individualize HDMTX dosing for at-risk patients with the aim of avoiding methotrexate-related toxicities.

Methods: We developed a simple algorithm to individualize HDMTX infusions with 0-2 rate adjustments based on methotrexate levels during the infusion. This was a prospective, open-label, study; eligible patients were identified and referred by their oncologist.

Results: Fifty-four evaluable cycles of HDMTX (5 g/m over 24 h) were administered to 22 patients. Blood samples were obtained in 21 patients to examine single nucleotide polymorphisms (SNPs) related to methotrexate disposition. Twelve (54.5%) subjects had a history of previous HDMTX toxicities including seven (31.8%) who previously required glucarpidase rescue and seven (31.8%) with an entry glomerular filtration rate < 80 ml/min/1.73 m. 107/110 (97.2%) of methotrexate levels were drawn properly and 100% of algorithm dosing instructions were performed correctly at the bedside. Thirty-five (64.8%) of all cycles and 24 of 33 (72.7%) cycles that required a dose-adjustment had an end 24-h methotrexate level (Cp) within our goal range of 65 ± 15 µM with only 3 (5.6%) resulting in Cp higher than goal. Grade 3/4 toxicities were rare; no patients developed > Grade 1 acute kidney injury.

Conclusion: This algorithm is a simple, safe and effective method for individualizing HDMTX in pediatric patients with ALL. CLINICALTRIALS.

Gov Registry: NCT02076997.
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http://dx.doi.org/10.1007/s00280-018-3733-2DOI Listing
February 2019

Exome sequencing disclosures in pediatric cancer care: Patterns of communication among oncologists, genetic counselors, and parents.

Patient Educ Couns 2019 04 12;102(4):680-686. Epub 2018 Nov 12.

Department of Medicine, Baylor College of Medicine, 6620 Main St., Houston, TX 77030, United States; Department of Communication, Texas A&M University, TAMU 4234, College Station, TX 77843, United States; Center for Innovation in Healthcare Quality, Effectiveness, & Safety, Michael E. DeBakey Veterans Affairs Medical Center, 2450 Holcombe Blvd., Suite 01Y, Houston, TX 77021, United States. Electronic address:

Objective: To examine communication patterns and behaviors during disclosure of exome sequencing (ES) results to parents of pediatric cancer patients, and describe common themes in parental communication.

Methods: Using mixed methods, we analyzed transcripts of sessions where parents of pediatric cancer patients received ES results from an oncologist and genetic counselor. Seventy-six transcripts were analyzed for frequency of clinician information-giving, partnering-supportive talk, and active parent participation. A subset of 40 transcripts were analyzed using thematic content analysis.

Results: Disclosures consisted mostly of clinician talk (84% of total talk), which was focused on providing information (62% of clinicians' utterances) with occasional partnering-supportive talk (7% of clinicians' utterances). Most parents assumed a passive, listening role (16% of total talk). Themes in parental communication included expressing relief and the significance of an answer, concern about sharing results and responsibility for inheritance, and seeking clarification of health implications of results.

Conclusion: Our finding of low levels of active parent participation during ES disclosures highlights the need to improve patient/parent engagement and understanding in a genetic setting.

Practice Implications: Clinician communication strategies that could encourage parent participation and understanding include checking for parent understanding, partnership-building, and tailoring ES discussions to address parent concerns and preferences.
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http://dx.doi.org/10.1016/j.pec.2018.11.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6440863PMC
April 2019

Publisher Correction: EMT cells increase breast cancer metastasis via paracrine GLI activation in neighbouring tumour cells.

Nat Commun 2018 11 12;9(1):4720. Epub 2018 Nov 12.

Department of Pharmacology, University of Colorado-Denver, 12800 East 19th Avenue, Room P18-6115, Aurora, Colorado, 80045, USA.

This Article contains an error in Figure 2. In panel a, the second lane of the western blot should have been labelled 'siNT'. A correct version of Figure 2a appears in the Author Correction associated with this Article; the error has not been fixed in the original Article.
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http://dx.doi.org/10.1038/s41467-018-07168-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6232083PMC
November 2018

Mammary Precancerous Stem and Non-Stem Cells Evolve into Cancers of Distinct Subtypes.

Cancer Res 2019 01 6;79(1):61-71. Epub 2018 Nov 6.

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

There are distinct cell subpopulations in normal epithelial tissue, including stem cells, progenitor cells, and more differentiated cells, all of which have been extensively studied for their susceptibility to tumorigenesis. However, normal cells usually have to progress through a precancerous lesion state before becoming a full-blown tumor. Precancerous early lesions are heterogeneous, and the cell subset that is the primary source of the eventual tumor remains largely unknown. By using mouse models that are tailored to address this question, we identified a keratin 6a-expressing precancerous stem cell (PcSC) subset and a more differentiated whey acidic protein-positive (WAP+) cell subset in mammary precancerous lesions initiated by the oncogene. Both cell subsets rapidly progressed to cancer upon introduction of constitutively active versions of either HRAS or BRAF. However, the resulting tumors were dramatically different in protein profiles and histopathology: keratin 6a+ precancerous cells gave rise to adenocarcinoma, whereas WAP+ cells yielded metaplastic carcinoma with severe squamous differentiation and more robust activation of MEK/ERK signaling. Therefore, both stem and non-stem cells in mammary precancerous lesions can contribute to the eventual cancers, but their differentiation status determines the resulting cancer phenotype. This work identifies a previously unknown player in cancer heterogeneity and suggests that cancer prevention should target precancerous cells broadly and not be limited to PcSC. SIGNIFICANCE: This work uses a novel mouse mammary gland cancer model to show that tumors initiated from different precancerous mammary epithelial cells are distinct.
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http://dx.doi.org/10.1158/0008-5472.CAN-18-1087DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6318055PMC
January 2019

Combination anti-Aβ treatment maximizes cognitive recovery and rebalances mTOR signaling in APP mice.

J Exp Med 2018 05 6;215(5):1349-1364. Epub 2018 Apr 6.

Department of Neuroscience, Baylor College of Medicine, Houston, TX

Drug development for Alzheimer's disease has endeavored to lower amyloid β (Aβ) by either blocking production or promoting clearance. The benefit of combining these approaches has been examined in mouse models and shown to improve pathological measures of disease over single treatment; however, the impact on cellular and cognitive functions affected by Aβ has not been tested. We used a controllable APP transgenic mouse model to test whether combining genetic suppression of Aβ production with passive anti-Aβ immunization improved functional outcomes over either treatment alone. Compared with behavior before treatment, arresting further Aβ production (but not passive immunization) was sufficient to stop further decline in spatial learning, working memory, and associative memory, whereas combination treatment reversed each of these impairments. Cognitive improvement coincided with resolution of neuritic dystrophy, restoration of synaptic density surrounding deposits, and reduction of hyperactive mammalian target of rapamycin signaling. Computational modeling corroborated by in vivo microdialysis pointed to the reduction of soluble/exchangeable Aβ as the primary driver of cognitive recovery.
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http://dx.doi.org/10.1084/jem.20171484DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5940263PMC
May 2018

Combinatorial inhibition of PTPN12-regulated receptors leads to a broadly effective therapeutic strategy in triple-negative breast cancer.

Nat Med 2018 05 26;24(4):505-511. Epub 2018 Mar 26.

Department of Molecular & Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer diagnosed in more than 200,000 women each year and is recalcitrant to targeted therapies. Although TNBCs harbor multiple hyperactive receptor tyrosine kinases (RTKs), RTK inhibitors have been largely ineffective in TNBC patients thus far. We developed a broadly effective therapeutic strategy for TNBC that is based on combined inhibition of receptors that share the negative regulator PTPN12. Previously, we and others identified the tyrosine phosphatase PTPN12 as a tumor suppressor that is frequently inactivated in TNBC. PTPN12 restrains several RTKs, suggesting that PTPN12 deficiency leads to aberrant activation of multiple RTKs and a co-dependency on these receptors. This in turn leads to the therapeutic hypothesis that PTPN12-deficient TNBCs may be responsive to combined RTK inhibition. However, the repertoire of RTKs that are restrained by PTPN12 in human cells has not been systematically explored. By methodically identifying the suite of RTK substrates (MET, PDGFRβ, EGFR, and others) inhibited by PTPN12, we rationalized a combination RTK-inhibitor therapy that induced potent tumor regression across heterogeneous models of TNBC. Orthogonal approaches revealed that PTPN12 was recruited to and inhibited these receptors after ligand stimulation, thereby serving as a feedback mechanism to limit receptor signaling. Cancer-associated mutation of PTPN12 or reduced PTPN12 protein levels diminished this feedback mechanism, leading to aberrant activity of these receptors. Restoring PTPN12 protein levels restrained signaling from RTKs, including PDGFRβ and MET, and impaired TNBC survival. In contrast with single agents, combined inhibitors targeting the PDGFRβ and MET receptors induced the apoptosis in TNBC cells in vitro and in vivo. This therapeutic strategy resulted in tumor regressions in chemo-refractory patient-derived TNBC models. Notably, response correlated with PTPN12 deficiency, suggesting that impaired receptor feedback may establish a combined addiction to these proto-oncogenic receptors. Taken together, our data provide a rationale for combining RTK inhibitors in TNBC and other malignancies that lack receptor-activating mutations.
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http://dx.doi.org/10.1038/nm.4507DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6675908PMC
May 2018

Vitamin D Levels, Vitamin D Receptor Polymorphisms, and Inflammatory Cytokines in Aromatase Inhibitor-Induced Arthralgias: An Analysis of CCTG MA.27.

Clin Breast Cancer 2018 02 16;18(1):78-87. Epub 2017 Oct 16.

Department of Internal Medicine, Mayo Clinic, Rochester, MN.

Background: Approximately half of women taking aromatase inhibitor (AI) therapy develop AI-induced arthralgia (AIA), and many might discontinue AI therapy because of the pain. Using plasma samples from the MA.27 study, we assessed several factors potentially associated with AIA.

Patients And Methods: MA.27 is a phase III adjuvant trial comparing 2 AIs, exemestane versus anastrozole. Within an 893-participant nested case-control AIA genome-wide association study, we nested a 72 AIA case-144 control assessment of vitamin D plasma concentrations, corrected for seasonal and geographic variation. We also examined 9 baseline inflammatory cytokines: interleukin (IL)-1β, IL-6, tumor necrosis factor-α, interferon (IFN)γ, IL-10, IL-12p70, IL-17, IL-23, and chemokine ligand (CCL)-20. Finally, we analyzed the multivariate effects of baseline factors: vitamin D level, previously identified musculoskeletal single nucleotide polymorphisms, age, body mass index, and vitamin D receptor (VDR) Fok-I variant genotype on AIA development.

Results: Changes in vitamin D from baseline to 6 months were not significantly different between cases and controls. Elevated inflammatory cytokine levels were not associated with development of AIA. The multivariate model included no clinical factors associated with AIA. However, women with the VDR Fok-I variant genotype were more likely to have a lower IL-1β level (P = .0091) and less likely to develop AIA after 6 months of AI compared with those with the wild type VDR (P < .0001).

Conclusion: In this nested case-control correlative study, vitamin D levels were not significantly associated with development of AIA; however, patients with the Fok-I VDR variant genotype were more likely to have a significant reduction in IL-1β level, and less likely to develop AIA.
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http://dx.doi.org/10.1016/j.clbc.2017.10.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7469602PMC
February 2018

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

Tenascin-C and Integrin α9 Mediate Interactions of Prostate Cancer with the Bone Microenvironment.

Cancer Res 2017 11 15;77(21):5977-5988. Epub 2017 Sep 15.

The Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas.

Deposition of the extracellular matrix protein tenascin-C is part of the reactive stroma response, which has a critical role in prostate cancer progression. Here, we report that tenascin C is expressed in the bone endosteum and is associated with formation of prostate bone metastases. Metastatic cells cultured on osteo-mimetic surfaces coated with tenascin C exhibited enhanced adhesion and colony formation as mediated by integrin α9β1. In addition, metastatic cells preferentially migrated and colonized tenascin-C-coated trabecular bone xenografts in a novel system that employed chorioallantoic membranes of fertilized chicken eggs as host. Overall, our studies deepen knowledge about reactive stroma responses in the bone endosteum that accompany prostate cancer metastasis to trabecular bone, with potential implications to therapeutically target this process in patients. .
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http://dx.doi.org/10.1158/0008-5472.CAN-17-0064DOI Listing
November 2017

EMT cells increase breast cancer metastasis via paracrine GLI activation in neighbouring tumour cells.

Nat Commun 2017 06 12;8:15773. Epub 2017 Jun 12.

Department of Pharmacology, University of Colorado-Denver, 12800 East 19th Avenue, Room P18-6115, Aurora, Colorado 80045, USA.

Recent fate-mapping studies concluded that EMT is not required for metastasis of carcinomas. Here we challenge this conclusion by showing that these studies failed to account for possible crosstalk between EMT and non-EMT cells that promotes dissemination of non-EMT cells. In breast cancer models, EMT cells induce increased metastasis of weakly metastatic, non-EMT tumour cells in a paracrine manner, in part by non-cell autonomous activation of the GLI transcription factor. Treatment with GANT61, a GLI1/2 inhibitor, but not with IPI 926, a Smoothened inhibitor, blocks this effect and inhibits growth in PDX models. In human breast tumours, the EMT-transcription factors strongly correlate with activated Hedgehog/GLI signalling but not with the Hh ligands. Our findings indicate that EMT contributes to metastasis via non-cell autonomous effects that activate the Hh pathway. Although all Hh inhibitors may act against tumours with canonical Hh/GLI signalling, only GLI inhibitors would act against non-canonical EMT-induced GLI activation.
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http://dx.doi.org/10.1038/ncomms15773DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5472791PMC
June 2017

A fully Bayesian latent variable model for integrative clustering analysis of multi-type omics data.

Biostatistics 2018 01;19(1):71-86

Division of Biostatistics, Dan L. Duncan Cancer Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.

Identification of clinically relevant tumor subtypes and omics signatures is an important task in cancer translational research for precision medicine. Large-scale genomic profiling studies such as The Cancer Genome Atlas (TCGA) Research Network have generated vast amounts of genomic, transcriptomic, epigenomic, and proteomic data. While these studies have provided great resources for researchers to discover clinically relevant tumor subtypes and driver molecular alterations, there are few computationally efficient methods and tools for integrative clustering analysis of these multi-type omics data. Therefore, the aim of this article is to develop a fully Bayesian latent variable method (called iClusterBayes) that can jointly model omics data of continuous and discrete data types for identification of tumor subtypes and relevant omics features. Specifically, the proposed method uses a few latent variables to capture the inherent structure of multiple omics data sets to achieve joint dimension reduction. As a result, the tumor samples can be clustered in the latent variable space and relevant omics features that drive the sample clustering are identified through Bayesian variable selection. This method significantly improve on the existing integrative clustering method iClusterPlus in terms of statistical inference and computational speed. By analyzing TCGA and simulated data sets, we demonstrate the excellent performance of the proposed method in revealing clinically meaningful tumor subtypes and driver omics features.
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http://dx.doi.org/10.1093/biostatistics/kxx017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6455926PMC
January 2018

HER2 Reactivation through Acquisition of the HER2 L755S Mutation as a Mechanism of Acquired Resistance to HER2-targeted Therapy in HER2 Breast Cancer.

Clin Cancer Res 2017 Sep 9;23(17):5123-5134. Epub 2017 May 9.

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

Resistance to anti-HER2 therapies in HER2 breast cancer can occur through activation of alternative survival pathways or reactivation of the HER signaling network. Here we employed BT474 parental and treatment-resistant cell line models to investigate a mechanism by which HER2 breast cancer can reactivate the HER network under potent HER2-targeted therapies. Resistant derivatives to lapatinib (L), trastuzumab (T), or the combination (LR/TR/LTR) were developed independently from two independent estrogen receptor ER/HER2 BT474 cell lines (AZ/ATCC). Two derivatives resistant to the lapatinib-containing regimens (BT474/AZ-LR and BT474/ATCC-LTR lines) that showed HER2 reactivation at the time of resistance were subjected to massive parallel sequencing and compared with parental lines. Ectopic expression and mutant-specific siRNA interference were applied to analyze the mutation functionally. and experiments were performed to test alternative therapies for mutant HER2 inhibition. Genomic analyses revealed that the L755S mutation was the only common somatic mutation gained in the BT474/AZ-LR and BT474/ATCC-LTR lines. Ectopic expression of L755S induced acquired lapatinib resistance in the BT474/AZ, SK-BR-3, and AU565 parental cell lines. L755S-specific siRNA knockdown reversed the resistance in BT474/AZ-LR and BT474/ATCC-LTR lines. The HER1/2-irreversible inhibitors afatinib and neratinib substantially inhibited both resistant cell growth and the HER2 and downstream AKT/MAPK signaling driven by L755S and HER2 reactivation through acquisition of the L755S mutation was identified as a mechanism of acquired resistance to lapatinib-containing HER2-targeted therapy in preclinical HER2-amplified breast cancer models, which can be overcome by irreversible HER1/2 inhibitors. .
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http://dx.doi.org/10.1158/1078-0432.CCR-16-2191DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5762201PMC
September 2017

Carbon nanotube capsules enhance the in vivo efficacy of cisplatin.

Acta Biomater 2017 08 2;58:466-478. Epub 2017 May 2.

Departments of Molecular and Cellular Biology and Radiology, Lester and Sue Smith Breast Center at Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA. Electronic address:

Over the past few years, numerous nanotechnology-based drug delivery systems have been developed in an effort to maximize therapeutic effectiveness of conventional drug delivery, while limiting undesirable side effects. Among these, carbon nanotubes (CNTs) are of special interest as potential drug delivery agents due to their numerous unique and advantageous physical and chemical properties. Here, we show in vivo favorable biodistribution and enhanced therapeutic efficacy of cisplatin (CDDP) encapsulated within ultra-short single-walled carbon nanotube capsules (CDDP@US-tubes) using three different human breast cancer xenograft models. In general, the CDDP@US-tubes demonstrated greater efficacy in suppressing tumor growth than free CDDP in both MCF-7 cell line xenograft and BCM-4272 patient-derived xenograft (PDX) models. The CDDP@US-tubes also demonstrated a prolonged circulation time compared to free CDDP which enhanced permeability and retention (EPR) effects resulting in significantly more CDDP accumulation in tumors, as determined by platinum (Pt) analysis via inductively-coupled plasma mass spectrometry (ICP-MS).

Statement Of Significance: Over the past decade, drug-loaded nanocarriers have been widely fabricated and studied to enhance tumor specific delivery. Among the diverse classes of nanomaterials, carbon nanotubes (CNTs), or more specifically ultra-short single-walled carbon nanocapsules (US-tubes), have been shown to be a popular, new platform for the delivery of various medical agents for both imaging and therapeutic purposes. Here, for the first time, we have shown that US-tubes can be utilized as a drug delivery platform in vivo to deliver the chemotherapeutic drug, cisplatin (CDDP) as CDDP@US-tubes. The studies have demonstrated the ability of the US-tube platform to promote the delivery of encapsulated CDDP by increasing the accumulation of drug in breast cancer resistance cells, which reveals how CDDP@US-tubes help overcome CDDP resistance.
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http://dx.doi.org/10.1016/j.actbio.2017.04.035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6344128PMC
August 2017