Resistance Mechanisms最新文献

{"title":"Abstract A47: Long-term treatment of bortezomib reduced resistance to doxorubicin by reducing CerS6/GCS and elevating CerS2/GBA expressions","authors":"Kim Shin, Kim Dongeun, Park Inkeun, Park Woo-Jae","doi":"10.1158/1557-3125.ADVBC17-A47","DOIUrl":"https://doi.org/10.1158/1557-3125.ADVBC17-A47","url":null,"abstract":"Multiple drug resistance (MDR) is main cause of chemotherapy failure in breast cancer. Herein, we tried to find the mechanism of MDR. Since overexpression of glucosylceramide synthase (GCS) plays an important role in development of MDR, we analyzed expression levels of many molecules from TCGA data to find a connection between GCS and other molecules. Interestingly, correlations between GCS and ceramide synthase 6 (CerS6), and between glucocerebosidase (GBA) and CerS2, 4, 5 were analyzed. To further analyze whether these correlations are true, we treated C16~C24-ceramide to MD-MBA-361 cells. C24-ceramide treatment for 48 and 72 hrs increased GBA expression, which increased susceptibility of apoptosis upon doxorubicin treatment. Moreover, C16-ceramide treatment for 16 weeks increased GCS expression, which also induced MDR1 protein expression. Recently we found that bortezomib, an FDA-approved proteasome inhibitor, increased CerS2 and decreased CerS6 expressions in a dose-dependent manner. To further understand whether bortezomib affects MDR, bortezomib was treated with doxorubicin for 6-8 months and it prevented doxorubicin-induced MDR development by reducing CerS6 and elevating CerS2. In conclusion, downregulation of CerS6 and upregulation of CerS2 is a good strategy to prevent development of MDR, and bortezomib can be used for the prevention of acquired MDR. Citation Format: Kim Shin, Kim Dongeun, Park Inkeun, Park Woo-Jae. Long-term treatment of bortezomib reduced resistance to doxorubicin by reducing CerS6/GCS and elevating CerS2/GBA expressions [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr A47.","PeriodicalId":20897,"journal":{"name":"Resistance Mechanisms","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81774490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract B36: Progesterone receptor signaling in estrogen receptor-positive breast cancer","authors":"Amy E. Young, Jane Guan, A. Daemen, L. Friedman, Kui Lin","doi":"10.1158/1557-3125.ADVBC17-B36","DOIUrl":"https://doi.org/10.1158/1557-3125.ADVBC17-B36","url":null,"abstract":"Approximately 65% of breast cancers are estrogen receptor alpha (ERα)-positive and depend on ERα signaling for growth. Clinical data indicate that ERα-positive breast cancers have a better prognosis when another hormone receptor, the progesterone receptor (PR), is coexpressed. Recent studies show that in the presence of its ligand progesterone, PR redirects ERα chromatin binding and transcriptional activity, thereby impacting prognosis and therapeutic response. To further examine PR function, we knocked out the PGR gene in the ERα-positive breast cancer cell lines MCF-7 and T47D using CRISPR-mediated gene editing. Knockout clones from each model were analyzed for ER- and PR-mediated transcriptional activity and gene expression profile, as well as response to selective estrogen receptor degraders (SERDs). The T47D cell line expresses high levels of PR in the presence or absence of estrogen, and stimulation with progesterone induces robust PR phosphorylation and modulation of PR target gene expression. Furthermore, progesterone attenuates estradiol-induced cell proliferation in a dose-dependent manner. Knockout of PR in this model abrogates the ability of progesterone to induce gene expression changes or attenuate estradiol-induced cell proliferation. In contrast, the MCF-7 cell line expresses low basal levels of PR, and is refractory to stimulation with progesterone. Interestingly, in estrogenic growth media, knockout of PR in this model results in basal gene expression changes that resemble a gene signature associated with tamoxifen resistance. Consistent with these findings, knockout of PR reduces the response to SERDs in a 5-day cell proliferation assay. ChIP-seq and RNA-seq analyses are ongoing to examine how loss of PR impacts ERα chromatin binding and transcriptional output. Citation Format: Amy Young, Jane Guan, Anneleen Daemen, Lori Friedman, Kui Lin. Progesterone receptor signaling in estrogen receptor-positive breast cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B36.","PeriodicalId":20897,"journal":{"name":"Resistance Mechanisms","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72733826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A45: Kinome rewiring reveals AURKA is a molecular barrier to the efficacy of PI3K/mTOR-pathway inhibitors in breast cancer","authors":"Hayley J. Donnella, James T. Webber, K. Shokat, A. Goga, J. Gordan, Sourav Bandyopadhyay","doi":"10.1158/1557-3125.ADVBC17-A45","DOIUrl":"https://doi.org/10.1158/1557-3125.ADVBC17-A45","url":null,"abstract":"Dysregulation of the PI3K-AKT-mTOR signaling network is a prominent feature of breast cancers. However, clinical responses to drugs targeting this pathway have been modest. We hypothesized that dynamic changes in signaling, including adaptation and feedback, limit drug efficacy. Using a quantitative proteomics approach, we mapped dynamic changes in the kinome in response to various agents and identified signaling changes that correlate with drug sensitivity. Measurement of dynamics across a panel of breast cancer cell lines identified that maintenance of CDK4 and AURKA activity was associated with drug resistance. We tested whether incomplete inhibition of CDK4 or AURKA was a source of therapy failure and found that inhibition of either was sufficient to sensitize most breast cancer cells to PI3K, AKT, and mTOR inhibitors. In particular, drug combinations including the AURKA inhibitor MLN8237 were highly synergistic and induced apoptosis through enhanced suppression of mTOR signaling to S6 and 4E-BP1 leading to tumor regression in vivo. This approach identifies survival factors whose presence limits the efficacy of target therapy and suggests that Aurora kinase coinhibition could unlock the full potential of PI3K-AKT-mTOR pathway inhibitors in breast cancer. Citation Format: Hayley Donnella, James Webber, Kevan Shokat, Andrei Goga, John Gordan, Sourav Bandyopadhyay. Kinome rewiring reveals AURKA is a molecular barrier to the efficacy of PI3K/mTOR-pathway inhibitors in breast cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr A45.","PeriodicalId":20897,"journal":{"name":"Resistance Mechanisms","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77636685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A42: Identifying relationships between high expression levels of the HSPA9 gene, putative HSPA9 alterations, and patient survivability in invasive breast carcinomas","authors":"Kofi K. Khamit-Kush, J. Lillard, V. Bond, Ming-bo Huang, W. Roth","doi":"10.1158/1557-3125.ADVBC17-A42","DOIUrl":"https://doi.org/10.1158/1557-3125.ADVBC17-A42","url":null,"abstract":"Metastasis is the primary cause for the lethality of breast cancer, and is responsible for approximately 90% of breast cancer-related deaths. Tumor cell resistance to cancer treatment continues to stymie efforts to effectively treat breast cancer, which we know to be primarily mediated by a highly conserved molecular chaperone in the heat shock protein 70 family known as mortalin. Mortalin is encoded by the gene HSPA9B localized on chromosome 5q31.1.1, and is low or undetectable in normal unstressed cells while highly expressed in many carcinomas. Breast cancer cell invasion and metastasis are closely related to adverse clinical outcomes and a worsened prognosis for patients. Previous studies have shown that breast cancer patients with high mortalin expression had decreased DFS and OS rates compared to those with low mortalin expression in early- or late-stage breast cancer. Conversely, low expression of mortalin decreases tumor cell progression and inhibits the epithelial-mesenchymal transition. Gene amplification is one of the major pathways by which proto-oncogenes are activated during tumorigenesis, and missense mutations in the gene of interest could potentially render a nonfunctional mortalin product. We examined three different publicly available datasets from the Genome Data Commons for possible relationships between alterations in the HSPA9 gene and BRCA patient survival rates. On a mutation-specific level, we compared the survival rates of the cases with a high frequency of HSPA9 alterations versus the cases without HSPA9 alterations. Our bioinformatics analysis of the BRCA datasets showed fourteen alterations in the HSPA9 gene that correlated to prognosis and survival rate in patients with breast cancer. Amplifications in the HSPA9 gene lead to lower survivability rates for the patient samples, while missense mutations in HSPA9 led to higher survivability rates. Also of interest, missense mutations were far more numerous than any other HSPA9 alteration type. Different alterations in the HSPA9 gene result in different mortalin protein products, ultimately leading to differences in prognosis for patients with invasive breast carcinomas. Our study supports that much of the clinically observable plasticity and heterogeneity occurs within, rather than across, the major biologic subtypes of breast cancer suggested by the variance in HSPA9 alteration types. Furthermore, the study supports that mortalin expression has a significant effect on breast cancer status and lends credence to mortalin as a survival predictor, particularly in BRCA patients. Note: This abstract was not presented at the conference. Citation Format: Kofi K. Khamit-Kush, James W. Lillard, Jr., Vincent C. Bond, Ming Huang, William Roth. Identifying relationships between high expression levels of the HSPA9 gene, putative HSPA9 alterations, and patient survivability in invasive breast carcinomas [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Can","PeriodicalId":20897,"journal":{"name":"Resistance Mechanisms","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87995081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract B34: Novel synergistic combination therapies with BET bromodomain inhibitors in triple-negative breast cancer","authors":"Samantha M. Bevill, N. Sciaky, B. Golitz, N. Rashid, J. Zawistowski, G. Johnson","doi":"10.1158/1557-3125.ADVBC17-B34","DOIUrl":"https://doi.org/10.1158/1557-3125.ADVBC17-B34","url":null,"abstract":"Adaptive resistance to targeted cancer therapies is a universal problem in cancer treatment where tumor cells circumvent targeted pathway inhibition to reactivate growth signaling. In our previous work, we observed genome-wide enhancer remodeling following MEK inhibition (MEKi) capable of driving adaptive gene transcription in triple-negative breast cancer (TNBC). Adaptive enhancers were enriched for the BET bromodomain protein BRD4 and cotreatment with MEKi and BET inhibitor (JQ1) could durably suppress TNBC growth in multiple cell lines and preclinical mouse models. There are currently 10 BET inhibitors in clinical trials being tested as single agents across multiple tumor types including TNBC. There is also a growing body of preclinical literature using epigenetic inhibitors to block the adaptive ability of tumor cells in combination with multiple targeted therapies. This led us to screen for inhibitors that synergize with JQ1 to suppress growth of TNBC using a 176-compound library enriched for epigenetic and kinase inhibitors. We performed synergy screens in 6 TNBC cell lines across 6 doses of JQ1 and each library compound. Using the Bliss Independence model to assess synergy, we found that inhibition of MEK, CDK9, Aurora Kinase, CREBBP/P300, and BAZ2A/B was strongly synergistic with JQ1. BRD4, CDK9, and the acetyltransferase CREBBP/P300 are all members of the P-TEFb transcriptional elongation complex. When we performed additional synergy screens against the P300 bromodomain inhibitor CPI-637, we found a significant overlap in synergistic targets with the JQ1 screen including MEK, BET bromodomain proteins, ERK, Aurora Kinase, and CDK9. BAZ2A/B inhibition using the small-molecule inhibitor GSK2801, which targets the bromodomain of BAZ2A/B, synergized significantly stronger with JQ1 across all cell lines compared to CPI637. BAZ2A/B proteins are members of nucleosome remodeling complexes that mediate DNA silencing by aiding in recruitment of histone modifying enzymes. Ongoing studies seek to understand the role of BAZ2A/B and the mechanism of GSK2801 synergy with BET bromodomain inhibition using RNA sequencing and ChIP sequencing experiments. These results define novel targets that synergize with JQ1 to suppress tumor cell growth and illuminate additional mechanisms of transcriptional regulation driven by BET bromodomain proteins in TNBC. Citation Format: Samantha M. Bevill, Noah Sciaky, Brian T. Golitz, Naim U. Rashid, Jon S. Zawistowski, Gary L. Johnson. Novel synergistic combination therapies with BET bromodomain inhibitors in triple-negative breast cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B34.","PeriodicalId":20897,"journal":{"name":"Resistance Mechanisms","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78056635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract PR05: The kinome of chemotherapy-resistant TNBC and identification of targetable kinases","authors":"C. L. V. D. Borden, Nina M. Koemans, B. Pan, Changjun Wang, D. Wolf, Jean-Philippe Coppé, L. Veer","doi":"10.1158/1557-3125.ADVBC17-PR05","DOIUrl":"https://doi.org/10.1158/1557-3125.ADVBC17-PR05","url":null,"abstract":"Triple-negative breast cancer (TNBC) accounts for around 15% of all breast cancer cases, with over 35,000 newly diagnosed women per year in the US. TNBC patients are at highest risk for recurrence, and neoadjuvant standard chemotherapy gives pathologic complete response in about 30% of these patients. Currently, no targeted therapy has been conclusively established to improve the outcome of TNBC patients, though successful phase II studies have been completed (1, 2). Therefore, identification of mechanisms that would be targetable is of great importance to improve the management of TNBC significantly. The aim of this study is to identify a unique set of hyperactivated kinases in chemotherapy-resistant TNBC cell lines that can potentially be targeted to achieve therapeutic response using a newly developed high-throughput kinase activity-mapping (HT-KAM) assay. The HT-KAM assay is our new screening technology to assess the catalytic activity of many kinases in parallel, which relies on collections of peptide probes that are used as combinatorial sensors to measure the phosphor-catalytic activity of kinases in large-scale high-throughput ATP-consumption assays (3). The HT-KAM system provides access to a new, untapped, and large resource of biologically meaningful measurements, both as a means to map the entire cancer kinome, and as a means to convert global phospho-signatures into functional patterns of kinase activity signatures. Kinome maps represent how kinase-signaling networks are rewired by drugs/targeted therapies in the context of different cellular backgrounds and exogenously mutated proteins/pathways, and provide insight into potentially targetable kinases. We previously established PhosphoAtlas, a heavily curated, comprehensive catalog database of 1,733 functionally interconnected proteins comprising the human phospho-reactome, including 4,748 unique edges that connect kinases to a target (776 kinase genes, 1,276 substrate protein genes, 2,492 heptameric peptide sequences [HPS]) (4). Here, we made a selection of 640 peptide sensors, capturing the functionality of >110 kinases over >900 kinase-substrate nodes directly relevant to tumor biology that represent the majority of the curated interconnected proteins, from our PhosphoAtlas (4). Earlier, the HT-KAM assay on 225 peptides was applied to explore mechanisms driving the unresponsiveness of colorectal and melanoma cancers to anti-BRAFV600E therapy in cell culture and patient-derived xenografts (PDX) (3). This successfully produced the predictive oncogenic kinome of melanoma tissues from patients suffering from fatal metastatic disease and, more importantly, identified new kinases/nodes that could be targeted to overcome drug resistance (3). In this study, we characterized the phospho-catalytic signatures of 10 TNBC cell lines (BT-549, HCC1143, HCC1395, HCC1937, HCC38, HCC70, HS578T, MDA-MB-231, MDA-MB-436, MDA-MB-468) across 640 peptides, either untreated or treated for 5 weeks with a ch","PeriodicalId":20897,"journal":{"name":"Resistance Mechanisms","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88299608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstract A50: Modeling and targeting of oncogenic proteotoxic stress in drug-resistant breast cancer","authors":"Navneet Singh, V. Modur, Belal Muhammad, K. Komurov","doi":"10.1158/1557-3125.ADVBC17-A50","DOIUrl":"https://doi.org/10.1158/1557-3125.ADVBC17-A50","url":null,"abstract":"ERBB2/HER2-positive breast cancers are associated with poor prognosis, and resistance to HER2-targeted therapy (trastuzumab and lapatinib) presents a significant clinical hurdle. There are no treatment options for metastatic HER2+ BCs that have progressed on HER2-targeted therapy. At present, most of the research on therapeutic strategies in therapy-refractory Her2+ BCs focuses on resensitizing tumor cells to HER2-targeting agents. We have shown that targeting of nononcogenic vulnerabilities, specifically adaptive proteotoxic stress response, is a promising therapeutic approach in this subset of BCs (Singh N. et al, HER2-mTOR signaling-driven breast cancer cells require ER-associated degradation to survive. Science Signaling 2015). We showed that Her2+ BCs have specific dependence on the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway to suppress the hyperactive Her2/mTOR pathway-driven proteotoxic stress. Here, we explore the kinetics of protein homeostatic changes during the course of Her2-targeted drug therapy, and identify optimal therapeutic windows for the targeting of ERAD in the therapy-refractory Her2+ BCs. Using an integrated systems approach, we have modeled the dynamics of signaling and protein homeostasis changes in Her2+ cells during remission, resistance, and relapse phases of Her2-targeted therapy. We found that the resistance and relapse phases of anti-Her2 drug (lapatinib and trastuzumab) treatment are associated with Her2-independent acquisition of mTOR signaling, as previously reported. However, these signaling pathway changes also resulted in heightened proteotoxic burden on the ER due to increased protein synthesis rates, which was further exacerbated upon the release of cells from anti-Her2 treatment. Accordingly, cells in the relapse phase, and even more so upon further drug withdrawal, showed significantly heightened sensitivity to the inhibition of ERAD. This study reveals the kinetics of protein homeostasis associated with the signaling pathway changes during acquired resistance to anti-Her2 therapy, and suggests optimal therapeutic windows for the targeting of ERAD in therapy-refractory Her2+ BCs. Citation Format: Navneet Singh, Vishnu Modur, Belal Muhammad, Kakajan Komurov. Modeling and targeting of oncogenic proteotoxic stress in drug-resistant breast cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr A50.","PeriodicalId":20897,"journal":{"name":"Resistance Mechanisms","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88565289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}