Apoptosis enhancing drugs overcome innate platinum resistance in CA125 negative tumor initiating populations of high grade serous ovarian cancer
ABSTRACT: High grade serous ovarian cancers (HGSC) are deadly malignancies that relapse despite carboplatin chemotherapy. Here we show that 16 independent primary HGSCs contain a CA125 negative population enriched for carboplatin resistant cancer initiating cells. Transcriptome analysis reveals up-regulation of homologous recombination DNA repair and anti-apoptotic signals in this population. While treatment with carboplatin enriches for CA125 negative cells, co-treatment with carboplatin and birinapant eliminates these cells in HGSCs expressing high levels of the inhibitor of apoptosis protein cIAP in the CA125 negative population. Birinapant sensitizes CA125 negative cells to carboplatin by mediating degradation of cIAP causing cleavage of caspase-8 and restoration of apoptosis. This co-therapy significantly improved disease free survival in vivo compared to either therapy alone in tumor-bearing mice. These findings suggest that therapeutic strategies that target CA125 negative cells may be useful in the treatment of HGSC. mRNA profiles of CA125 positive and negative populations, generated by next generation sequencing of populations FACS isolated from 10 independent dissociated primary human high grade serous ovarian cancers, were compared.
Project description:High grade serous ovarian cancers (HGSC) are deadly malignancies that relapse despite carboplatin chemotherapy. Many commercially ovarian cancer cell lines are not good models for HGSC. Here we demonstrate that 3 low passage cell lines derived from HGSC have similar transcriptomes to their parental bulk tumors. These cell lines recapitulated tumor characteristics of the primary cancer and had responded to therapy in the same manner as primary HGSC cells, demonstrating they are accurate models for HGSCs. mRNA profiles of low passage high grade serous tumor cell lines and their parental tumors, generated by next generation sequencing, were compared.
Project description:High grade serous ovarian cancers (HGSC) are deadly malignancies that relapse despite carboplatin chemotherapy. Many commercially ovarian cancer cell lines are not good models for HGSC. Here we demonstrate that 3 low passage cell lines derived from HGSC have similar transcriptomes to their parental bulk tumors. These cell lines recapitulated tumor characteristics of the primary cancer and had responded to therapy in the same manner as primary HGSC cells, demonstrating they are accurate models for HGSCs. Overall design: mRNA profiles of low passage high grade serous tumor cell lines and their parental tumors, generated by next generation sequencing, were compared.
Project description:Profiling of loss of heterozygosity (LOH) in HGSC, subcrouping HGSC by LOH-based clustering and comparing to the LOH profiles of triple-negative breast cancer [previously submitted; GSE19594]. Study for the correlation of LOH burdern and LOH-based subgroups to clinical response to platinum-based chemotherapy in patients suffered from HGSC. SNP data (Affymetrix GenChip 250K SNP Nsp) from 47 high grade serous ovarian cancer were generated and used for LOH and copy number analysis, LOH-based hierarchical clustering to subclassify HGSC, and comparison to the chromosomal alterations in high grade brest cancer. The associstion between LOH-based subgroups and LOH burden and clinical resposne to platinum-based chemotherapy was investigated. The results were validated in two independent public opening datasets.
Project description:Recent evidence suggests that ovarian high-grade serous carcinoma (HGSC) originates from the epithelium of the fallopian tube. However, most mouse models are based on the previous prevailing view that ovarian cancer develops from the transformation of the ovarian surface epithelium. Here, we report the extensive histological and molecular characterization of the mogp-TAg transgenic mouse, which expresses the SV40 large T-antigen (TAg) under the control of the mouse müllerian-specific Ovgp-1 promoter. Histologic analysis of the fallopian tubes of mogp-TAg mice identified a variety of neoplastic lesions analogous to those described as precursors to ovarian HGSC. We identified areas of normal appearing p53-positive epithelium that are similar to “p53 signatures” in the human fallopian tube. More advanced proliferative lesions with nuclear atypia and epithelial stratification were also identified that were morphologically and immunohistochemically reminiscent of human serous tubal intraepithelial carcinoma (STIC), a potential precursor of ovarian HGSC. Beside these noninvasive precursor lesions, we also identified invasive adenocarcinoma in the ovary of 56% of the mice. Microarray analysis revealed several genes differentially expressed between the fallopian tube of mogp-TAg and WT C57BL/6. One of these genes, Top2a, which encodes topoisomerase II-alpha, was shown by immunohistochemistry to be concurrently expressed with elevated p53 and specifically elevated in mouse STICs, but not in surrounding tissues. TOP2A protein was also found elevated in human STICs, low-grade, and high-grade serous carcinoma. The mouse model reported here displays a progression from normal tubal epithelium to invasive HGSC in the ovary, and therefore closely simulates the current emerging model of human ovarian HGSC pathogenesis. This mouse therefore has the potential to be a very useful new model for elucidating the mechanisms of serous ovarian tumorigenesis, as well as for developing novel approaches for the prevention, diagnosis, and therapy of this disease. Keywords: transgenic mouse model, ovarian cancer, fallopian tube, intraepithelial carcinoma 6 mouse fallopian tubes (FT) were analyzed with experimental repeats; 3 wildtype C57BL6 mice (FT) and 3 transgenic mogp-TAg (FT), with one set of each at 7, 8 and 9 weeks of age.
Project description:The high degree of genetic aberrations characteristic of high-grade serous ovarian cancer (HGSC) makes identification of the molecular features that drive tumor progression difficult. Here, we perform genome-wide RNAi screens and comprehensive expression analysis of cell surface markers in a panel of HGSC cell lines to identify genes that are critical to their survival. We report that the tetraspanin CD151 contributes to survival of a subset of HGSC cell lines associated with a ZEB transcriptional program and supports the growth of HGSC tumors. Moreover, we show that high CD151 expression is prognostic of poor clinical outcome. This study reveals cell-surface vulnerabilities associated with HGSC, provides a framework for identifying therapeutic targets, and reports a role for CD151 in HGSC. Overall design: 40 epithelial ovarian cancer cell lines and one immortalized line derived from ovarian surface epithelium (OE-E6/E7)
Project description:Precision medicine approaches in ovarian cancer require the accurate diagnosis of histotypes. In particular, there is a critical need to distinguish endometroid (EC) from high grade serous (HGSC) carcinomas, which differ greatly in outcomes, genetic predisposition and optimal treatment approaches. Herein, we performed label-free quantitative proteomics on freshly frozen tumour tissues to discover biomarkers that may distinguish EC from HGSC, and then used IHC to validate these using a contemporarily classified cohort of EC and HGSC samples.
Project description:Our study presents the first genetic models of de novo high-grade serous carcinomas (HGSC) that originate in fallopian tube secretory epithelial cells and recapitulate the key genetic alterations and precursor lesions characteristic of human invasive ovarian cancer. Genomic copy number analysis, using array CGH, was performed on murine tumors in order to compare the overlap of copy number alterations between HGSC models and TCGA data. Array CGH was performed on genomic DNA isolated from murine HGSC tumors. Genomic DNA from three normal mouse fallopian tubes was pooled and used as the reference.
Project description:To identify the potential ovarian cancer stem cell gene expression profile from isolated side population of fresh ascites obtained from women with high-grade advanced stage papillary serous ovarian adenocarcinoma Microarrays were used to interrogate the differentially expressed genes between side population (SP) and main population (MP) isolated from fresh ascites obtained from women with high-grade advanced stage papillary serous ovarian adenocarcinoma, and the results were analyzed by paired T-test using BRB-ArrayTools Gene expression profiling was completed for 10 SP and MP pairs using the Affymetrix human U133 Plus 2.0 Arrays
Project description:Integration of genomic copy number analysis (Affymetrix SNP6.0 arrays) and oncogenic RAS/RAF mutation status with clinical features and tumour progression. This study found that loss of the 9p and the CDKN2A locus with the most significantly enriched copy number aberration distinguishing serous border tumors from low grade serous carcinomas, suggesting this is a key step to tumor progression. Epithelial tissue from 57 serous borderline tumors (SBTs), 19 low grade serous carcinomas (LGSC)(data for 4 of the carcinomas have previously been submitted to GEO - Series GSE19539) and 355 high grade serous carinomas (HGSC)(TCGA, 2011; GSE19539; and 8 new) were analysed for copy number aberrations using Affymetrix SNP6.0 arrays and normalised SNP6.0 data. Stromal tissue from 38 SBT and 1 HGSC were analysed for copy number aberrations using Affymetrix SNP6.0 arrays. Matching lymphocyte DNA was availabe for 54 SBT, 3 LGSC and 1 HGSC. Sanger sequencing of KRAS, BRAF, NRAS, HRAS, ERBB2 and TP53 mutational hotspots was performed on the epithelial and stromal DNA. This information was then correlated with clinical features of the tumors.
Project description:Ovarian cancer is the fifth leading cause of cancer death among US women. Evidence supports the hypothesis that high-grade serous ovarian cancers (HGSC) may originate in the distal end of the fallopian tube. Although a heterogeneous disease, 96% of HGSC contain mutations in p53. In addition, the “p53 signature”, or overexpression of p53 protein (usually associated with mutation), is a potential precursor lesion of fallopian tube derived HGSC suggesting an essential role for p53 mutation in early serous tumorigenesis. To further clarify p53-mutation dependent effects on cells, murine oviductal epithelial cells (MOE) were stably transfected with a construct encoding for the R273H DNA binding domain mutation in p53, the most common mutation in HGSC. Mutation in p53 was not sufficient to transform MOE cells, but did significantly increase cell migration. A similar p53 mutation in murine ovarian surface epithelium (MOSE), another potential progenitor cell for serous cancer, was not sufficient to transform the cells nor change migration suggesting tissue specific effects of p53 mutation. Microarray data confirmed expression changes in pro-migratory genes in p53R273H MOE compared to parental cells, which could be reversed by suppressing Slug expression. Combining p53R273H with KRASG12V activation caused transformation of MOE into high-grade sarcomatoid carcinoma when xenografted into nude mice. Elucidating the specific role of p53R273H in the fallopian tube will improve understanding of changes at the earliest stage of transformation and could help develop chemopreventative strategies to prevent the accumulation of additional mutations and reverse progression of the “p53 signature” thereby, improving survival rates. We used a microarray to determine global changes in gene expression as a result of the p53 mutation specifically in mouse oviductal epithelium. Murine oviductal cells (MOE) were obtained from Dr. Barbara Vanderhyden at the University of Ottawa. Stable cell lines were generated using antibiotic resistant plasmids containing p53 R273H (Addgene, plasmid: 16439, donated by Dr. Vogelstein, Johns Hopkins University school of Medicine, Baltimore, MD) or pCMV-Neo (Origene PCMV6XL4, Rockville, MD). Total RNA was extracted from cell pellets collected from consecutive passages.