Publications by authors named "Preethi Korangath"

20 Publications

  • Page 1 of 1

Magnet-assisted Flow Cytometry of Tumors to Quantitate Cell-specific Responses to Magnetic Iron Oxide Nanoparticles.

Bio Protoc 2020 Nov 20;10(22):e3822. Epub 2020 Nov 20.

Dept of Radiation Oncology and Molecular Radiation Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD 21231 USA.

A clear understanding of nanoparticle interactions with living systems at the cellular level is necessary for developing nanoparticle-based therapeutics. Magnetic iron oxide nanoparticles provide unique opportunities to study these interactions because of their responsiveness to magnetic fields. This enables sorting of cells containing nanoparticles from models. Once sorted, flow cytometry can identify individual cell types, which can be further analyzed for iron content, gene or protein expression changes associated with nanoparticle uptake, and for other biological responses at a molecular level. Here we provide a detailed protocol to sort and identify cells in the tumor microenvironment that have internalized magnetic iron oxide nanoparticles following intravenous administration.
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http://dx.doi.org/10.21769/BioProtoc.3822DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7842744PMC
November 2020

HEYL Regulates Neoangiogenesis Through Overexpression in Both Breast Tumor Epithelium and Endothelium.

Front Oncol 2020 15;10:581459. Epub 2021 Jan 15.

Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United States.

Blocking tumor angiogenesis is an appealing therapeutic strategy, but to date, success has been elusive. We previously identified HEYL, a downstream target of Notch signaling, as an overexpressed gene in both breast cancer cells and as a tumor endothelial marker, suggesting that HEYL overexpression in both compartments may contribute to neoangiogenesis. Carcinomas arising in double transgenic Her2-neu/HeyL mice showed higher tumor vessel density and significantly faster growth than tumors in parental Her2/neu mice. Providing mechanistic insight, microarray-based mRNA profiling of HS578T-tet-off-HEYL human breast cancer cells revealed upregulation of several angiogenic factors including CXCL1/2/3 upon HEYL expression, which was validated by RT-qPCR and protein array analysis. Upregulation of the cytokines CXCL1/2/3 occurred through direct binding of HEYL to their promoter sequences. We found that vessel growth and migration of human vascular endothelial cells (HUVECs) was promoted by conditioned medium from HS578T-tet-off-HEYL carcinoma cells, but was blocked by neutralizing antibodies against CXCL1/2/3. Supporting these findings, suppressing HEYL expression using shRNA in MDA-MB-231 cells significantly reduced tumor growth. In addition, suppressing the action of proangiogenic cytokines induced by HEYL using a small molecule inhibitor of the CXCl1/2/3 receptor, CXCR2, in combination with the anti-VEGF monoclonal antibody, bevacizumab, significantly reduced tumor growth of MDA-MB-231 xenografts. Thus, HEYL expression in tumor epithelium has a profound effect on the vascular microenvironment in promoting neoangiogenesis. Furthermore, we show that lack of HEYL expression in endothelial cells leads to defects in neoangiogenesis, both under normal physiological conditions and in cancer. Thus, HeyL-/- mice showed impaired vessel outgrowth in the neonatal retina, while the growth of mammary tumor cells E0771 was retarded in syngeneic HeyL-/- mice compared to wild type C57/Bl6 mice. Blocking HEYL's angiogenesis-promoting function in both tumor cells and tumor-associated endothelium may enhance efficacy of therapy targeting the tumor vasculature in breast cancer.
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http://dx.doi.org/10.3389/fonc.2020.581459DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7845423PMC
January 2021

Systemically delivered antibody-labeled magnetic iron oxide nanoparticles are less toxic than plain nanoparticles when activated by alternating magnetic fields.

Int J Hyperthermia 2020 Dec;37(3):59-75

Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Objective: Toxicity from off-target heating with magnetic hyperthermia (MHT) is generally assumed to be understood. MHT research focuses on development of more potent heating magnetic iron oxide nanoparticles (MIONs), yet our understanding of factors that define biodistribution following systemic delivery remains limited. Preclinical development relies on mouse models, thus understanding off-target heating with MHT in mice provides critical knowledge for clinical development.

Methods: Eight-week old female nude mice received a single tail vein injection of bionized nanoferrite (BNF) MIONs or a counterpart labeled with a polyclonal human antibody (BNF-IgG) at 1 mg, 3 mg or 5 mg Fe/mouse on day 1. On day 3, mice were exposed to an alternating magnetic field (AMF) having amplitude of 32, 48 or 64 kA/m at ∼145 kHz for 20 min. Twenty-four hours later, blood, livers and spleens were harvested and analyzed.

Results: Damage to livers was apparent by histology and serum liver enzymes following MHT with BNF or BNF-IgG at doses ≥3 mg Fe and AMF amplitudes ≥48 kA/m. Differences between effects with BNF vs. BNF-IgG at a dose of 3 mg Fe were noted in all measures, with less damage and increased survival occurring in mice injected with BNF-IgG. Necropsies revealed severe damage to duodenum and upper small intestines, likely the immediate cause of death at the highest MHT doses.

Conclusion: Results demonstrate that the MION coating affects biodistribution, which in turn determines off-target effects. Developments to improve heating capabilities of MIONs may be clinically irrelevant without better control of biodistribution.
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http://dx.doi.org/10.1080/02656736.2020.1776901DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7810240PMC
December 2020

Cancer therapy with iron oxide nanoparticles: Agents of thermal and immune therapies.

Adv Drug Deliv Rev 2020 27;163-164:65-83. Epub 2020 Jun 27.

Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Oncology, Sidney Kimmel Comprehensive Cancer Centre, School of Medicine, Johns Hopkins University, Baltimore, MD 21231, USA; Department of Materials Science and Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore 21218, USA; Department of Mechanical Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore 21218, USA. Electronic address:

Significant research and preclinical investment in cancer nanomedicine has produced several products, which have improved cancer care. Nevertheless, there exists a perception that cancer nanomedicine 'has not lived up to its promise' because the number of approved products and their clinical performance are modest. Many of these analyses do not consider the long clinical history and many clinical products developed from iron oxide nanoparticles. Iron oxide nanoparticles have enjoyed clinical use for about nine decades demonstrating safety, and considerable clinical utility and versatility. FDA-approved applications of iron oxide nanoparticles include cancer diagnosis, cancer hyperthermia therapy, and iron deficiency anemia. For cancer nanomedicine, this wealth of clinical experience is invaluable to provide key lessons and highlight pitfalls in the pursuit of nanotechnology-based cancer therapeutics. We review the clinical experience with systemic liposomal drug delivery and parenteral therapy of iron deficiency anemia (IDA) with iron oxide nanoparticles. We note that the clinical success of injectable iron exploits the inherent interaction between nanoparticles and the (innate) immune system, which designers of liposomal drug delivery seek to avoid. Magnetic fluid hyperthermia, a cancer therapy that harnesses magnetic hysteresis heating is approved for treating humans only with iron oxide nanoparticles. Despite its successful demonstration to enhance overall survival in clinical trials, this nanotechnology-based thermal medicine struggles to establish a clinical presence. We review the physical and biological attributes of this approach, and suggest reasons for barriers to its acceptance. Finally, despite the extensive clinical experience with iron oxide nanoparticles new and exciting research points to surprising immune-modulating potential. Recent data demonstrate the interactions between immune cells and iron oxide nanoparticles can induce anti-tumor immune responses. These present new and exciting opportunities to explore additional applications with this venerable technology. Clinical applications of iron oxide nanoparticles present poignant case studies of the opportunities, complexities, and challenges in cancer nanomedicine. They also illustrate the need for revised paradigms and multidisciplinary approaches to develop and translate nanomedicines into clinical cancer care.
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http://dx.doi.org/10.1016/j.addr.2020.06.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7736167PMC
June 2020

For HIPEC, synergistic effects of hyperthermia and doxorubicin are optimal when simultaneously combined.

Int J Hyperthermia 2020 ;37(1):346-348

Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

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http://dx.doi.org/10.1080/02656736.2020.1750714DOI Listing
April 2020

Nanoparticle interactions with immune cells dominate tumor retention and induce T cell-mediated tumor suppression in models of breast cancer.

Sci Adv 2020 03 25;6(13):eaay1601. Epub 2020 Mar 25.

Department of Radiation Oncology and Molecular Radiation Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD 21231, USA.

The factors that influence nanoparticle fate in vivo following systemic delivery remain an area of intense interest. Of particular interest is whether labeling with a cancer-specific antibody ligand ("active targeting") is superior to its unlabeled counterpart ("passive targeting"). Using models of breast cancer in three immune variants of mice, we demonstrate that intratumor retention of antibody-labeled nanoparticles was determined by tumor-associated dendritic cells, neutrophils, monocytes, and macrophages and not by antibody-antigen interactions. Systemic exposure to either nanoparticle type induced an immune response leading to CD8 T cell infiltration and tumor growth delay that was independent of antibody therapeutic activity. These results suggest that antitumor immune responses can be induced by systemic exposure to nanoparticles without requiring a therapeutic payload. We conclude that immune status of the host and microenvironment of solid tumors are critical variables for studies in cancer nanomedicine and that nanoparticle technology may harbor potential for cancer immunotherapy.
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http://dx.doi.org/10.1126/sciadv.aay1601DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7096167PMC
March 2020

Enhancing the abscopal effect of radiation and immune checkpoint inhibitor therapies with magnetic nanoparticle hyperthermia in a model of metastatic breast cancer.

Int J Hyperthermia 2019 11;36(sup1):47-63

Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Enhancing immune responses in triple negative breast cancers (TNBCs) remains a challenge. Our study aimed to determine whether magnetic iron oxide nanoparticle (MION) hyperthermia (HT) can enhance abscopal effects with radiotherapy (RT) and immune checkpoint inhibitors (IT) in a metastatic TNBC model. One week after implanting 4T1-luc cells into the mammary glands of BALB/c mice, tumors were treated with RT (3 × 8 Gy)±local HT, mild (HT, 43 °C/20 min) or partially ablative (HT, 45 °C/5 min plus 43 °C/15 min),±IT with anti-PD-1 and anti-CTLA-4 antibodies (both 4 × 10 mg/kg, i.p.). Tumor growth was measured daily. Two weeks after treatment, lungs and livers were harvested for histopathology evaluation of metastases. Compared to untreated controls, all treatment groups demonstrated a decreased tumor volume; however, when compared against surgical resection, only RT + HT+IT, RT + HT+IT and RT + HT had similar or smaller tumors. These cohorts showed more infiltration of CD3 T-lymphocytes into the primary tumor. Tumor growth effects were partially reversed with T-cell depletion. Combinations that proved most effective for primary tumors generated modest reductions in numbers of lung metastases. Conversely, numbers of lung metastases showed potential to increase following HT + IT treatment, particularly when compared to RT. Compared to untreated controls, there was no improvement in survival with any treatment. Single-fraction MION HT added to RT + IT improved local tumor control and recruitment of CD3 T-lymphocytes, with only a modest effect to reduce lung metastases and no improvement in overall survival. HT + IT showed potential to increase metastatic dissemination to lungs.
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http://dx.doi.org/10.1080/02656736.2019.1685686DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7017719PMC
November 2019

Discovery of a Potent GLUT Inhibitor from a Library of Rapafucins by Using 3D Microarrays.

Angew Chem Int Ed Engl 2019 11 31;58(48):17158-17162. Epub 2019 Oct 31.

Department of Pharmacology and Molecular Sciences, The SJ Yan and HJ Mao Laboratory of Chemical Biology, Johns Hopkins University School of Medicine, Room 516, Hunterian Building, 725 N. Wolfe Street, Baltimore, MD, USA.

Glucose transporters play an essential role in cancer cell proliferation and survival and have been pursued as promising cancer drug targets. Using microarrays of a library of new macrocycles known as rapafucins, which were inspired by the natural product rapamycin, we screened for new inhibitors of GLUT1. We identified multiple hits from the rapafucin 3D microarray and confirmed one hit as a bona fide GLUT1 ligand, which we named rapaglutin A (RgA). We demonstrate that RgA is a potent inhibitor of GLUT1 as well as GLUT3 and GLUT4, with an IC value of low nanomolar for GLUT1. RgA was found to inhibit glucose uptake, leading to a decrease in cellular ATP synthesis, activation of AMP-dependent kinase, inhibition of mTOR signaling, and induction of cell-cycle arrest and apoptosis in cancer cells. Moreover, RgA was capable of inhibiting tumor xenografts in vivo without obvious side effects. RgA could thus be a new chemical tool to study GLUT function and a promising lead for developing anticancer drugs.
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http://dx.doi.org/10.1002/anie.201905578DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6861656PMC
November 2019

Increased uptake of doxorubicin by cells undergoing heat stress does not explain its synergistic cytotoxicity with hyperthermia.

Int J Hyperthermia 2019 ;36(1):712-720

a Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine , Baltimore , MD , USA.

A proposed mechanism for the enhanced effectiveness of hyperthermia and doxorubicin (Dox) combinations is increased intracellular Dox concentrations resulting from heat-induced cell stress. The purpose of this study was to determine whether specific varied Dox and heat combinations produce measurable effects greater than the additive combination, and whether these effects can be attributed to heat-induced increases in intracellular Dox concentrations. HCT116, HT29 and CT26 cells were exposed to Dox and water bath heating independently. A clonogenic survival assay was used to determine cell killing and intracellular Dox concentrations were measured in HCT116 cells with mass spectrometry. Cells were exposed to heating at 42 °C (60 min) and 0.5 µg/ml of Dox at varying intervals. Synergy was determined by curve-fitting and isobologram analysis. All cell lines displayed synergistic effects of combined heating and Dox. A maximum synergistic effect was achieved with simultaneous cell exposure to Dox and heat. For exposures at 42 °C, the synergistic effect was most pronounced at Dox concentrations <0.5 µg/ml. Increased intracellular concentrations of Dox in HCT116 cells caused by heat-stress did not generate a concomitant thermal enhancement. Simultaneous exposure of HCT116 cells to heating and Dox is more effective than sequential exposure. Heat-induced cell responses are accompanied by increased intracellular Dox concentrations; however, clonogenic survival data do not support this as the cause for synergistic cytotoxicity.
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http://dx.doi.org/10.1080/02656736.2019.1631494DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6934043PMC
January 2020

Intraductal fulvestrant for therapy of ERα-positive ductal carcinoma in situ of the breast: a preclinical study.

Carcinogenesis 2019 07;40(7):903-913

Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Mammographic screening for breast cancer has led to increased detection of ductal carcinoma in situ (DCIS) and a reappraisal of the necessity of aggressive treatment with their attendant toxicities for a preneoplastic lesion. Fulvestrant, a selective estrogen receptor degrader, is very effective in the treatment of estrogen receptor positive (ER+) breast cancer, but delivery by the painful intramuscular (i.m) route is limiting. We hypothesized that intraductal (i.duc) administration of fulvestrant will provide a direct, safe and effective treatment for DCIS. Mice bearing mammary ductal xenografts of ER+, luciferase-tagged MCF-7 breast cancer cells were administered vehicle or fulvestrant i.m or i.duc. I.duc MCF-7-luc tumors in mice treated with fulvestrant i.duc or i.m grew significantly slower than vehicle control. Whole mount analysis and histopathology showed that i.duc fulvestrant achieved significantly larger cancer-free areas. Western blot analysis showed reduced levels of estrogen receptor alpha (ERα) and its downstream targets, c-Myc and Cyclin D1, and increased levels of ERβ, which is known to inhibit ERα function. Immunohistochemical analysis of tumor sections showed that Ki67 and ERα protein levels decreased by 3-fold, and neoangiogenesis was inhibited by i.duc fulvestrant treatment. I.duc fulvestrant also reduced outgrowth of ERα+, autochthonous N-methyl-N-nitrosourea-induced mammary tumors in rats. Overall, we have shown that i.duc fulvestrant was significantly more effective than, or equivalent in action to i.m fulvestrant in two preclinical models of breast cancer. These studies provide evidence for a novel and safe route for fulvestrant therapy of DCIS and prevention of breast cancer. This preclinical study provides a strong basis for conducting clinical trials for DCIS and early breast cancer.
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http://dx.doi.org/10.1093/carcin/bgz084DOI Listing
July 2019

Physical characterization and in vivo organ distribution of coated iron oxide nanoparticles.

Sci Rep 2018 03 20;8(1):4916. Epub 2018 Mar 20.

Johns Hopkins University School of Medicine, Department of Radiation Oncology and Molecular Radiation Sciences, 1550 Orleans Street, CRB II, Baltimore, MD, 21231, USA.

Citrate-stabilized iron oxide magnetic nanoparticles (MNPs) were coated with one of carboxymethyl dextran (CM-dextran), polyethylene glycol-polyethylene imine (PEG-PEI), methoxy-PEG-phosphate+rutin, or dextran. They were characterized for size, zeta potential, hysteresis heating in an alternating magnetic field, dynamic magnetic susceptibility, and examined for their distribution in mouse organs following intravenous delivery. Except for PEG-PEI-coated nanoparticles, all coated nanoparticles had a negative zeta potential at physiological pH. Nanoparticle sizing by dynamic light scattering revealed an increased nanoparticle hydrodynamic diameter upon coating. Magnetic hysteresis heating changed little with coating; however, the larger particles demonstrated significant shifts of the peak of complex magnetic susceptibility to lower frequency. 48 hours following intravenous injection of nanoparticles, mice were sacrificed and tissues were collected to measure iron concentration. Iron deposition from nanoparticles possessing a negative surface potential was observed to have highest accumulation in livers and spleens. In contrast, iron deposition from positively charged PEG-PEI-coated nanoparticles was observed to have highest concentration in lungs. These preliminary results suggest a complex interplay between nanoparticle size and charge determines organ distribution of systemically-delivered iron oxide magnetic nanoparticles.
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http://dx.doi.org/10.1038/s41598-018-23317-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5861066PMC
March 2018

HOXC10 Expression Supports the Development of Chemotherapy Resistance by Fine Tuning DNA Repair in Breast Cancer Cells.

Cancer Res 2016 08 14;76(15):4443-56. Epub 2016 Jun 14.

Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland.

Development of drug resistance is a major factor limiting the continued success of cancer chemotherapy. To overcome drug resistance, understanding the underlying mechanism(s) is essential. We found that HOXC10 is overexpressed in primary carcinomas of the breast, and even more significantly in distant metastasis arising after failed chemotherapy. High HOXC10 expression correlates with shorter recurrence-free and overall survival in patients with estrogen receptor-negative breast cancer undergoing chemotherapy. We found that HOXC10 promotes survival in cells treated with doxorubicin, paclitaxel, or carboplatin by suppressing apoptosis and upregulating NF-κB Overexpressed HOXC10 increases S-phase-specific DNA damage repair by homologous recombination (HR) and checkpoint recovery in cells at three important phases. For double-strand break repair, HOXC10 recruits HR proteins at sites of DNA damage. It enhances resection and lastly, it resolves stalled replication forks, leading to initiation of DNA replication following DNA damage. We show that HOXC10 facilitates, but is not directly involved in DNA damage repair mediated by HR. HOXC10 achieves integration of these functions by binding to, and activating cyclin-dependent kinase, CDK7, which regulates transcription by phosphorylating the carboxy-terminal domain of RNA polymerase II. Consistent with these findings, inhibitors of CDK7 reverse HOXC10-mediated drug resistance in cultured cells. Blocking HOXC10 function, therefore, presents a promising new strategy to overcome chemotherapy resistance in breast cancer. Cancer Res; 76(15); 4443-56. ©2016 AACR.
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http://dx.doi.org/10.1158/0008-5472.CAN-16-0774DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4970943PMC
August 2016

A Self-Folding Hydrogel In Vitro Model for Ductal Carcinoma.

Tissue Eng Part C Methods 2016 Apr 16;22(4):398-407. Epub 2016 Mar 16.

1 Department of Chemical and Biomolecular Engineering, Johns Hopkins University , Baltimore, Maryland.

A significant challenge in oncology is the need to develop in vitro models that accurately mimic the complex microenvironment within and around normal and diseased tissues. Here, we describe a self-folding approach to create curved hydrogel microstructures that more accurately mimic the geometry of ducts and acini within the mammary glands, as compared to existing three-dimensional block-like models or flat dishes. The microstructures are composed of photopatterned bilayers of poly (ethylene glycol) diacrylate (PEGDA), a hydrogel widely used in tissue engineering. The PEGDA bilayers of dissimilar molecular weights spontaneously curve when released from the underlying substrate due to differential swelling ratios. The photopatterns can be altered via AutoCAD-designed photomasks so that a variety of ductal and acinar mimetic structures can be mass-produced. In addition, by co-polymerizing methacrylated gelatin (methagel) with PEGDA, microstructures with increased cell adherence are synthesized. Biocompatibility and versatility of our approach is highlighted by culturing either SUM159 cells, which were seeded postfabrication, or MDA-MB-231 cells, which were encapsulated in hydrogels; cell viability is verified over 9 and 15 days, respectively. We believe that self-folding processes and associated tubular, curved, and folded constructs like the ones demonstrated here can facilitate the design of more accurate in vitro models for investigating ductal carcinoma.
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http://dx.doi.org/10.1089/ten.TEC.2015.0442DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4827285PMC
April 2016

Combined Treatment with Epigenetic, Differentiating, and Chemotherapeutic Agents Cooperatively Targets Tumor-Initiating Cells in Triple-Negative Breast Cancer.

Cancer Res 2016 04 19;76(7):2013-2024. Epub 2016 Jan 19.

Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Efforts to induce the differentiation of cancer stem cells through treatment with all-trans retinoic acid (ATRA) have yielded limited success, partially due to the epigenetic silencing of the retinoic acid receptor (RAR)-β The histone deacetylase inhibitor entinostat is emerging as a promising antitumor agent when added to the standard-of-care treatment for breast cancer. However, the combination of epigenetic, cellular differentiation, and chemotherapeutic approaches against triple-negative breast cancer (TNBC) has not been investigated. In this study, we found that combined treatment of TNBC xenografts with entinostat, ATRA, and doxorubicin (EAD) resulted in significant tumor regression and restoration of epigenetically silenced RAR-β expression. Entinostat and doxorubicin treatment inhibited topoisomerase II-β (TopoII-β) and relieved TopoII-β-mediated transcriptional silencing of RAR-β Notably, EAD was the most effective combination in inducing differentiation of breast tumor-initiating cells in vivo Furthermore, gene expression analysis revealed that the epithelium-specific ETS transcription factor-1 (ESE-1 or ELF3), known to regulate proliferation and differentiation, enhanced cell differentiation in response to EAD triple therapy. Finally, we demonstrate that patient-derived metastatic cells also responded to treatment with EAD. Collectively, our findings strongly suggest that entinostat potentiates doxorubicin-mediated cytotoxicity and retinoid-driven differentiation to achieve significant tumor regression in TNBC. Cancer Res; 76(7); 2013-24. ©2016 AACR.
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http://dx.doi.org/10.1158/0008-5472.CAN-15-1619DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4873448PMC
April 2016

Phytochemicals in Cancer Prevention and Therapy.

Biomed Res Int 2015 13;2015:324021. Epub 2015 Dec 13.

Translational Research Institute, Academic Health System, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar.

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http://dx.doi.org/10.1155/2015/324021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4691454PMC
October 2016

HOXB7 Is an ERα Cofactor in the Activation of HER2 and Multiple ER Target Genes Leading to Endocrine Resistance.

Cancer Discov 2015 Sep 15;5(9):944-59. Epub 2015 Jul 15.

Breast Cancer Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland.

Unlabelled: Why breast cancers become resistant to tamoxifen despite continued expression of the estrogen receptor-α (ERα) and what factors are responsible for high HER2 expression in these tumors remains an enigma. HOXB7 chromatin immunoprecipitation analysis followed by validation showed that HOXB7 physically interacts with ERα, and that the HOXB7-ERα complex enhances transcription of many ERα target genes, including HER2. Investigating strategies for controlling HOXB7, our studies revealed that MYC, stabilized via phosphorylation mediated by EGFR-HER2 signaling, inhibits transcription of miR-196a, a HOXB7 repressor. This leads to increased expression of HOXB7, ER target genes, and HER2. Repressing MYC using small-molecule inhibitors reverses these events and causes regression of breast cancer xenografts. The MYC-HOXB7-HER2 signaling pathway is eminently targetable in endocrine-resistant breast cancer.

Significance: HOXB7 acts as an ERα cofactor regulating a myriad of ER target genes, including HER2, in tamoxifen-resistant breast cancer. HOXB7 expression is controlled by MYC via transcriptional regulation of the HOXB7 repressor miR-196a; consequently, antagonists of MYC cause reversal of selective ER modulator resistance both in vitro and in vivo.
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http://dx.doi.org/10.1158/2159-8290.CD-15-0090DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4560624PMC
September 2015

Targeting Glutamine Metabolism in Breast Cancer with Aminooxyacetate.

Clin Cancer Res 2015 Jul 26;21(14):3263-73. Epub 2015 Mar 26.

Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland.

Purpose: Glutamine addiction in c-MYC-overexpressing breast cancer is targeted by the aminotransferase inhibitor, aminooxyacetate (AOA). However, the mechanism of ensuing cell death remains unresolved.

Experimental Design: A correlation between glutamine dependence for growth and c-MYC expression was studied in breast cancer cell lines. The cytotoxic effects of AOA, its correlation with high c-MYC expression, and effects on enzymes in the glutaminolytic pathway were investigated. AOA-induced cell death was assessed by measuring changes in metabolite levels by magnetic resonance spectroscopy (MRS), the effects of amino acid depletion on nucleotide synthesis by cell-cycle and bromodeoxyuridine (BrdUrd) uptake analysis, and activation of the endoplasmic reticulum (ER) stress-mediated pathway. Antitumor effects of AOA with or without common chemotherapies were determined in breast cancer xenografts in immunodeficient mice and in a transgenic MMTV-rTtA-TetO-myc mouse mammary tumor model.

Results: We established a direct correlation between c-MYC overexpression, suppression of glutaminolysis, and AOA sensitivity in most breast cancer cells. MRS, cell-cycle analysis, and BrdUrd uptake measurements indicated depletion of aspartic acid and alanine leading to cell-cycle arrest at S-phase by AOA. Activation of components of the ER stress-mediated pathway, initiated through GRP78, led to apoptotic cell death. AOA inhibited growth of SUM159, SUM149, and MCF-7 xenografts and c-myc-overexpressing transgenic mouse mammary tumors. In MDA-MB-231, AOA was effective only in combination with chemotherapy.

Conclusions: AOA mediates its cytotoxic effects largely through the stress response pathway. The preclinical data of AOA's effectiveness provide a strong rationale for further clinical development, particularly for c-MYC-overexpressing breast cancers.
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http://dx.doi.org/10.1158/1078-0432.CCR-14-1200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4696069PMC
July 2015

The Notch pathway inhibits TGFβ signaling in breast cancer through HEYL-mediated crosstalk.

Cancer Res 2014 Nov 12;74(22):6509-18. Epub 2014 Sep 12.

Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland.

Acquired resistance to TGFβ is a key step in the early stages of tumorigenesis. Mutations in TGFβ signaling components are rare, and little is known about the development of resistance in breast cancer. On the other hand, an activated Notch pathway is known to play a substantial role in promoting breast cancer development. Here, we present evidence of crosstalk between these two pathways through HEYL. HEYL, a basic helix-loop-helix transcription factor and a direct target of Notch signaling, is specifically overexpressed in breast cancer. HEYL represses TGFβ activity by binding to TGFβ-activated Smads. HeyL(-/-) mice have defective mammary gland development with fewer terminal end buds. On the other hand, HeyL transgenic mice show accelerated mammary gland epithelial proliferation and 24% of multiparous mice develop mammary gland cancer. Therefore, repression of TGFβ signaling by Notch acting through HEYL may promote initiation of breast cancer.
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http://dx.doi.org/10.1158/0008-5472.CAN-14-0816DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4233182PMC
November 2014

Notch signaling pathway targeted therapy suppresses tumor progression and metastatic spread in pancreatic cancer.

Cancer Lett 2013 Jul 10;335(1):41-51. Epub 2013 Feb 10.

Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Pancreatic ductal adenocarcinoma (PDA) remains a lethal human malignancy with historically limited success in treatment. The role of aberrant Notch signaling, which requires the constitutive activation of γ-secretase, in the initiation and progression of PDA is well defined and inhibitors of this pathway are currently in clinical trials. Here we investigated the in vivo therapeutic effect of PF-03084014, a selective γ-secretase inhibitor, alone and in combination with gemcitabine in pancreatic cancer xenografts. PF-03084014 treatment inhibited the cleavage of nuclear Notch 1 intracellular domain and Notch targets Hes-1 and Hey-1. Gemcitabine treatment showed good response but not capable of inducing tumor regressions and targeting the tumor-resident cancer stem cells (CD24(+)CD44(+) and ALDH(+) tumor cells). A combination of PF-03084014 and gemcitabine treatment resulted tumor regression in 3 of 4 subcutaneously implanted xenograft models. PF-03084014, and in combination with gemcitabine reduced putative cancer stem cells, indicating that PF-03084014 target the especially dangerous and resilient cancer stem cells within pancreatic tumors. Tumor re-growth curves plotted after drug treatments demonstrated that the effect of the combination therapy was sustainable than that of gemcitabine. Notably, in a highly aggressive orthotopic model, PF-03084014 and gemcitabine combination was effective in inducing apoptosis, inhibition of tumor cell proliferation and angiogenesis, resulting in the attenuation of primary tumor growth as well as controlling metastatic dissemination, compared to gemcitabine treatment. In summary, our preclinical data suggest that PF-03084014 has greater anti-tumor activity in combination with gemcitabine in PDA and provides rationale for further investigation of this combination in PDA.
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http://dx.doi.org/10.1016/j.canlet.2013.01.054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3665739PMC
July 2013

Inhibition of metastasis of B16F-10 melanoma cells in C57BL/6 mice by an extract of Calendula officinalis L flowers.

Asian Pac J Cancer Prev 2010 ;11(6):1773-9

Department of Biochemistry, Amala Cancer Research Centre, Amala Nagar, Thrissur, Kerala, India.

Aim: To determine the effect of a Calendula officinalis flower extract on lung metastasis by B16F-10 melanoma cells in C57BL/6 mice.

Materials And Methods: Male mice were injected with B16F-10 melanoma cells through the tail vein and simultaneously treated with C.officinalis flower extract. Parameters studied were lung tumor nodule count, life span of animals, gamma glutamyl transpeptidase activity, sialic acid, TNF-α, IL-1β, IL-6, IL-2, GM-CSF, VEGF and TIMP-1 levels in serum, and lung hydroxyproline, uronic acid and hexosamine levels, as well as histopathological features. Effects of C.officinalis on the expression of various genes involved in metastasis like matrix metalloproteases (MMPs), tissue inhibitor of metalloproteases (TIMPs), prolyl hydoxylase, lysyl oxidase, nm23, and proinflammatory cytokines were also investigated.

Results: Simultaneous administration of C. officinalis extract to tumor bearing C57BL/6 mice reduced the lung tumor nodules by 74% with 43.3% increase in life span. Elevated levels of hydroxyproline, uronic acid, hexosamine, serum sialic acid and γ-glutamyl transpeptidase in the metastatic controls were found to be significantly lowered in the C. officinalis treated animals. The extract also inhibited expression of MMP-2, MMP-9, prolyl hydroxylase and lysyl oxidase and activated TIMP-1 and TIMP-2 and downregulated proinflammatory cytokines.

Conclusions: The present investigation indicated antimetastatic effects of Calendula officinalis flowers through the inhibition of key enzymes involved in processes of metastasis.
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July 2011