Browsing by Author "Goswami, Chirayu P."

Now showing 1 - 8 of 8
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    Expression levels of SF3B3 correlate with prognosis and endocrine resistance in estrogen receptor-positive breast cancer
    (Nature Publishing Group, 2015-05) Gökmen-Polar, Yesim; Neelamraju, Yaseswini; Goswami, Chirayu P.; Gu, Xiaoping; Nallamothu, Gouthami; Janga, Sarath Chandra; Badve, Sunil; Department of Pathology and Laboratory Medicine, IU School of Medicine
    De novo or acquired resistance to endocrine therapy limits its utility in a significant number of estrogen receptor-positive (ER-positive) breast cancers. It is crucial to identify novel targets for therapeutic intervention and improve the success of endocrine therapies. Splicing factor 3b, subunit 1 (SF3B1) mutations are described in luminal breast cancer albeit in low frequency. In this study, we evaluated the role of SF3B1 and SF3B3, critical parts of the SF3b splicing complex, in ER-positive endocrine resistance. To ascertain the role of SF3B1/SF3B3 in endocrine resistance, their expression levels were evaluated in ER-positive/endocrine-resistant cell lines (MCF-7/LCC2 and MCF-7/LCC9) using a real-time quantitative reverse transcription PCR (qRT-PCR). To further determine their clinical relevance, expression analysis was performed in a cohort of 60 paraffin-embedded ER-positive, node-negative breast carcinomas with low, intermediate, and high Oncotype DX recurrence scores. Expression levels of SF3B1 and SF3B3 and their prognostic value were validated in large cohorts using publicly available gene expression data sets including The Cancer Genome Atlas. SF3B1 and SF3B3 levels were significantly increased in ERα-positive cells with acquired tamoxifen (MCF-7/LCC2; both P<0.0002) and fulvestrant/tamoxifen resistance (MCF-7/LCC9; P=0.008 for SF3B1 and P=0.0006 for SF3B3). Expression levels of both MCF-7/LCC2 and MCF-7/LCC9 were not affected by additional treatments with E2 and/or tamoxifen. Furthermore, qRT-PCR analysis confirmed that SF3B3 expression is significantly upregulated in Oncotype DX high-risk groups when compared with low risk (P=0.019). Similarly, in publicly available breast cancer gene expression data sets, overexpression of SF3B3, but not SF3B1, was significantly correlated with overall survival. Furthermore, the correlation was significant in ER-positive, but not in ER-negative tumors.
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    Gene Expression Analysis Reveals Distinct Pathways of Resistance to Bevacizumab in Xenograft Models of Human ER-Positive Breast Cancer
    (Ivyspring, 2014) Gökmen-Polar, Yesim; Goswami, Chirayu P.; Toroni, Rachel A.; Sanders, Kerry L.; Mehta, Rutika; Sirimalle, Usha; Tanasa, Bogdan; Shen, Changyu; Li, Lang; Ivan, Mircea; Badve, Sunil S.; Sledge, George W.; Pathology and Laboratory Medicine, School of Medicine
    Bevacizumab, the recombinant antibody targeting vascular endothelial growth factor (VEGF), improves progression-free but not overall survival in metastatic breast cancer. To seek further insights in resistance mechanisms to bevacizumab at the molecular level, we developed VEGF and non-VEGF-driven ER-positive MCF7-derived xenograft models allowing comparison of tumor response at different timepoints. VEGF gene (MV165) overexpressing xenografts were initially sensitive to bevacizumab, but eventually acquired resistance. In contrast, parental MCF7 cells derived tumors were de novo insensitive to bevacizumab. Microarray analysis with qRT-PCR validation revealed that Follistatin (FST) and NOTCH were the top signaling pathways associated with resistance in VEGF-driven tumors (P<0.05). Based on the presence of VEGF, treatment with bevacizumab resulted in altered patterns of metagenes and PAM50 gene expression. In VEGF-driven model after short and long-term bevacizumab treatments, a change in the intrinsic subtype (luminal to myoepithelial/basal-like) was observed in association with increased expression of genes implicated with cancer stem cell phenotype (P<0.05). Our results show that the presence or absence of VEGF expression affects the response to bevacizumab therapy and gene pathways. In particular, long-term bevacizumab treatment shifts the cancer cells to a more aggressive myoepithelial/basal subtype in VEGF-expressing model, but not in non-VEGF model. These findings could shed light on variable results to anti-VEGF therapy in patients and emphasize the importance of patient stratification based on the VEGF expression. Our data strongly suggest consideration of patient subgroups for treatment and designing novel combinatory therapies in the clinical setting.
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    Gene expression profiles among murine strains segregate with distinct differences in the progression of radiation-induced lung disease
    (The Company of Biologists, 2017-04-01) Jackson, Isabel L.; Baye, Fitsum; Goswami, Chirayu P.; Katz, Barry P.; Zodda, Andrew; Pavlovic, Radmila; Gurung, Ganga; Winans, Don; Vujaskovic, Zeljko; Biostatistics, School of Public Health
    Molecular mechanisms underlying development of acute pneumonitis and/or late fibrosis following thoracic irradiation remain poorly understood. Here, we hypothesize that heterogeneity in disease progression and phenotypic expression of radiation-induced lung disease (RILD) across murine strains presents an opportunity to better elucidate mechanisms driving tissue response toward pneumonitis and/or fibrosis. Distinct differences in disease progression were observed in age- and sex-matched CBA/J, C57L/J and C57BL/6J mice over 1 year after graded doses of whole-thorax lung irradiation (WTLI). Separately, comparison of gene expression profiles in lung tissue 24 h post-exposure demonstrated >5000 genes to be differentially expressed (P<0.01; >twofold change) between strains with early versus late onset of disease. An immediate divergence in early tissue response between radiation-sensitive and -resistant strains was observed. In pneumonitis-prone C57L/J mice, differentially expressed genes were enriched in proinflammatory pathways, whereas in fibrosis-prone C57BL/6J mice, genes were enriched in pathways involved in purine and pyrimidine synthesis, DNA replication and cell division. At 24 h post-WTLI, different patterns of cellular damage were observed at the ultrastructural level among strains but microscopic damage was not yet evident under light microscopy. These data point toward a fundamental difference in patterns of early pulmonary tissue response to WTLI, consistent with the macroscopic expression of injury manifesting weeks to months after exposure. Understanding the mechanisms underlying development of RILD might lead to more rational selection of therapeutic interventions to mitigate healthy tissue damage.
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    Identification and validation of genes with expression patterns inverse to multiple metastasis suppressor genes in breast cancer cell lines
    (Springer-Verlag, 2014-10) Marino, Natascia; Collins, Joshua W.; Shen, Changyu; Caplen, Natasha J.; Merchant, Anand S.; Gökmen-Polar, Yesim; Goswami, Chirayu P.; Hoshino, Takashi; Qian, Yongzhen; Sledge, George W.; Steeg, Patricia S.; Department of Pathology and Laboratory Medicine, IU School of Medicine
    Metastasis suppressor genes (MSGs) have contributed to an understanding of regulatory pathways unique to the lethal metastatic process. When re-expressed in experimental models, MSGs block cancer spread to, and colonization of distant sites without affecting primary tumor formation. Genes have been identified with expression patterns inverse to a single MSG, and found to encode functional, druggable signaling pathways. We now hypothesize that common signaling pathways mediate the effects of multiple MSGs. By gene expression profiling of human MCF7 breast carcinoma cells expressing a scrambled siRNA, or siRNAs to each of 19 validated MSGs (NME1, BRMS1, CD82, CDH1, CDH2, CDH11, CASP8, MAP2K4, MAP2K6, MAP2K7, MAPK14, GSN, ARHGDIB, AKAP12, DRG1, CD44, PEBP1, RRM1, KISS1), we identified genes whose expression was significantly opposite to at least five MSGs. Five genes were selected for further analysis: PDE5A, UGT1A, IL11RA, DNM3 and OAS1. After stable downregulation of each candidate gene in the aggressive human breast cancer cell line MDA-MB-231T, in vitro motility was significantly inhibited. Two stable clones downregulating PDE5A (phosphodiesterase 5A), an enzyme involved in the regulation of cGMP-specific signaling, exhibited no difference in cell proliferation, but reduced motility by 47 and 66 % compared to the empty vector-expressing cells (p = 0.01 and p = 0.005). In an experimental metastasis assay, two shPDE5A-MDA-MB-231T clones produced 47-62 % fewer lung metastases than shRNA-scramble expressing cells (p = 0.045 and p = 0.009 respectively). This study demonstrates that previously unrecognized genes are inversely related to the expression of multiple MSGs, contribute to aspects of metastasis, and may stand as novel therapeutic targets.
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    Identification of FDA-approved Drugs Targeting Breast Cancer Stem Cells Along With Biomarkers of Sensitivity
    (Nature Research, 2013-08-28) Bhat-Nakshatri, Poornima; Goswami, Chirayu P.; Badve, Sunil; Sledge, George W.; Nakshatri, Harikrishna
    Recently developed genomics-based tools are allowing repositioning of Food and Drug Administration (FDA)-approved drugs as cancer treatments, which were employed to identify drugs that target cancer stem cells (CSCs) of breast cancer. Gene expression datasets of CSCs from six studies were subjected to connectivity map to identify drugs that may ameliorate gene expression patterns unique to CSCs. All-trans retinoic acid (ATRA) was negatively connected with gene expression in CSCs. ATRA reduced mammosphere-forming ability of a subset of breast cancer cells, which correlated with induction of apoptosis, reduced expression of SOX2 but elevated expression of its antagonist CDX2. SOX2/CDX2 ratio had prognostic relevance in CSC-enriched breast cancers. K-ras mutant breast cancer cell line enriched for CSCs was resistant to ATRA, which was reversed by MAP kinase inhibitors. Thus, ATRA alone or in combination can be tested for efficacy using SOX2, CDX2, and K-ras mutation/MAPK activation status as biomarkers of response.
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    Molecular Insights of Pathways Resulting From Two Common PIK3CA Mutations in Breast Cancer
    (AACR, 2016-07) Bhat-Nakshatri, Poornima; Goswami, Chirayu P.; Badve, Sunil; Magnani, Luca; Lupien, Mathieu; Nakshatri, Harikrishna; Department of Surgery, IU School of Medicine
    The PI3K pathway is activated in approximately 70% of breast cancers. PIK3CA gene mutations or amplifications that affect the PI3K p110α subunit account for activation of this pathway in 20% to 40% of cases, particularly in estrogen receptor alpha (ERα)-positive breast cancers. AKT family of kinases, AKT1–3, are the downstream targets of PI3K and these kinases activate ERα. Although several inhibitors of PI3K have been developed, none has proven effective in the clinic, partly due to an incomplete understanding of the selective routing of PI3K signaling to specific AKT isoforms. Accordingly, we investigated in this study the contribution of specific AKT isoforms in connecting PI3K activation to ERα signaling, and we also assessed the utility of using the components of PI3K–AKT isoform–ERα signaling axis as predictive biomarkers of response to PI3K inhibitors. Using a variety of physiologically relevant model systems with defined natural or knock-in PIK3CA mutations and/or PI3K hyperactivation, we show that PIK3CA-E545K mutations (found in ∼20% of PIK3CA-mutant breast cancers), but not PIK3CA-H1047R mutations (found in 55% of PIK3CA-mutant breast cancers), preferentially activate AKT1. Our findings argue that AKT1 signaling is needed to respond to estrogen and PI3K inhibitors in breast cancer cells with PIK3CA-E545K mutation, but not in breast cancer cells with other PIK3CA mutations. This study offers evidence that personalizing treatment of ER-positive breast cancers to PI3K inhibitor therapy may benefit from an analysis of PIK3CA–E545K–AKT1–estrogen signaling pathways.
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    Organ-specific adaptive signaling pathway activation in metastatic breast cancer cells
    (Impact Journals, LLC, 2015-05-20) Burnett, Riesa M.; Craven, Kelly E.; Krishnamurthy, Purna; Goswami, Chirayu P.; Badve, Sunil; Crooks, Peter; Mathews, William P.; Bhat-Nakshatri, Poornima; Nakshatri, Harikrishna; Department of Surgery, IU School of Medicine
    Breast cancer metastasizes to bone, visceral organs, and/or brain depending on the subtype, which may involve activation of a host organ-specific signaling network in metastatic cells. To test this possibility, we determined gene expression patterns in MDA-MB-231 cells and its mammary fat pad tumor (TMD-231), lung-metastasis (LMD-231), bone-metastasis (BMD-231), adrenal-metastasis (ADMD-231) and brain-metastasis (231-BR) variants. When gene expression between metastases was compared, 231-BR cells showed the highest gene expression difference followed by ADMD-231, LMD-231, and BMD-231 cells. Neuronal transmembrane proteins SLITRK2, TMEM47, and LYPD1 were specifically overexpressed in 231-BR cells. Pathway-analyses revealed activation of signaling networks that would enable cancer cells to adapt to organs of metastasis such as drug detoxification/oxidative stress response/semaphorin neuronal pathway in 231-BR, Notch/orphan nuclear receptor signals involved in steroidogenesis in ADMD-231, acute phase response in LMD-231, and cytokine/hematopoietic stem cell signaling in BMD-231 cells. Only NF-κB signaling pathway activation was common to all except BMD-231 cells. We confirmed NF-κB activation in 231-BR and in a brain metastatic variant of 4T1 cells (4T1-BR). Dimethylaminoparthenolide inhibited NF-κB activity, LYPD1 expression, and proliferation of 231-BR and 4T1-BR cells. Thus, transcriptome change enabling adaptation to host organs is likely one of the mechanisms associated with organ-specific metastasis and could potentially be targeted therapeutically.
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    Splicing factor ESRP1 controls ER-positive breast cancer by altering metabolic pathways
    (EMBO Press, 2019-02) Gökmen‐Polar, Yesim; Neelamraju, Yaseswini; Goswami, Chirayu P.; Gu, Yuan; Gu, Xiaoping; Nallamothu, Gouthami; Vieth, Edyta; Janga, Sarath C.; Ryan, Michael; Badve, Sunil S.; Pathology and Laboratory Medicine, School of Medicine
    The epithelial splicing regulatory proteins 1 and 2 (ESRP1 and ESRP2) control the epithelial-to-mesenchymal transition (EMT) splicing program in cancer. However, their role in breast cancer recurrence is unclear. In this study, we report that high levels of ESRP1, but not ESRP2, are associated with poor prognosis in estrogen receptor positive (ER+) breast tumors. Knockdown of ESRP1 in endocrine-resistant breast cancer models decreases growth significantly and alters the EMT splicing signature, which we confirm using TCGA SpliceSeq data of ER+ BRCA tumors. However, these changes are not accompanied by the development of a mesenchymal phenotype or a change in key EMT-transcription factors. In tamoxifen-resistant cells, knockdown of ESRP1 affects lipid metabolism and oxidoreductase processes, resulting in the decreased expression of fatty acid synthase (FASN), stearoyl-CoA desaturase 1 (SCD1), and phosphoglycerate dehydrogenase (PHGDH) at both the mRNA and protein levels. Furthermore, ESRP1 knockdown increases the basal respiration and spare respiration capacity. This study reports a novel role for ESRP1 that could form the basis for the prevention of tamoxifen resistance in ER+ breast cancer.