We studied the whole-genome point mutation and structural variation patterns of 133 tumors (59 high-grade serous (HGSC), 35 clear cell (CCOC), 29 endometrioid (ENOC), and 10 adult granulosa cell (GCT)) as a substrate for class discovery in ovarian cancer. Ab initio clustering of integrated point mutation and structural variation signatures identified seven subgroups both between and within histotypes. Prevalence of foldback inversions identified a prognostically significant HGSC group associated with inferior survival. This finding was recapitulated in two independent cohorts (n = 576 cases), transcending BRCA1 and BRCA2 mutation and gene expression features of HGSC. CCOC cancers grouped according to APOBEC deamination (26%) and age-related mutational signatures (40%). ENOCs were divided by cases with microsatellite instability (28%), with a distinct mismatch-repair mutation signature. Taken together, our work establishes the potency of the somatic genome, reflective of diverse DNA repair deficiencies, to stratify ovarian cancers into distinct biological strata within the major histotypes.

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The p38 MAPK mediates transcriptional and posttranscriptional control of cyclooxygenase-2 (COX-2) mRNA following interleukin-1(IL-1)/lipopolysaccharide cellular activation. We explored a positive feedback, prostaglandin E 2 (PGE 2 )-dependent stabilization of COX-2 mRNA mediated by the p38 MAPK cascade in IL-1␤-stimulated human synovial fibroblasts. We observed a rapid (5 min), massive (>30-fold), and sustained (>48 h) increase in COX-2 mRNA, protein, and PGE 2 release following a recombinant human (rh) IL-1␤ signal that was inhibited by NS-398, a COX-2 inhibitor, and SB202190, a selective, cell-permeable p38 MAPK inhibitor. PGE 2 completely reversed NS-398-mediated inhibition but not SB202190-dependent inhibition. The eicosanoid didn't potentiate IL-1␤-induced COX-2 expression nor did it activate COX-2 gene expression in quiescent cells. Transfection experiments with a human COX-2 promoter construct revealed a minor element of p38 MAPK-dependent transcriptional control after IL-1␤ stimulation. p38 MAPK synergized with the cAMP/cAMP-dependent protein kinase cascade to transactivate the COX-2 promoter. When human synovial fibroblasts were activated with rhIL-1␤ for 3-4 h (steady state) followed by washout, the elevated levels of COX-2 mRNA declined rapidly (<2 h) to control levels. If PGE 2 , unlike EP2/3 agonists butaprost and sulprostone, was added to fresh medium, COX-2 mRNA levels remained elevated for up to 16 h. SB202190 or anti-PGE 2 monoclonal antibody compromised the stabilization of COX-2 mRNA by PGE 2 . Deletion analysis using transfected chimeric luciferase-COX-2 mRNA 3-untranslated region reporter constructs revealed that IL-1␤ increased reporter gene mRNA stability and translation via AU-containing distal regions of the untranslated region. This response was mediated entirely by a PGE 2 /p38 MAPK-dependent process. We conclude that the magnitude and duration of the induction of COX-2 mRNA, protein, and PGE 2 release by rhIL-1␤ is primarily the result of PGE 2 -dependent stabilization of COX-2 mRNA and stimulation of translation, a process involving a positive feedback loop mediated by the EP4 receptor and the downstream kinases p38 MAPK and, perhaps, cAMP-dependent protein kinase.

BackgroundCell line models have proven to be effective tools to investigate a variety of ovarian cancer features. Due to the limited number of cell lines, particularly of the serous subtype, the heterogeneity of the disease, and the lack of cell lines that model disease progression, there is a need to further develop cell line resources available for research. This study describes nine cell lines derived from three ovarian cancer cases that were established at initial diagnosis and at subsequent relapse after chemotherapy.MethodsThe cell lines from three women diagnosed with high-grade serous ovarian cancer (1369, 2295 and 3133) were derived from solid tumor (TOV) and ascites (OV), at specific time points at diagnosis and relapse (R). Primary treatment was a combination of paclitaxel/carboplatin (1369, 3133), or cisplatin/topotecan (2295). Second line treatment included doxorubicin, gemcitabine and topotecan. In addition to molecular characterization (p53, HER2), the cell lines were characterized based on cell growth characteristics including spheroid growth, migration potential, and anchorage independence. The in vivo tumorigenicity potential of the cell lines was measured. Response to paclitaxel and carboplatin was assessed using a clonogenic assay.ResultsAll cell lines had either a nonsense or missense TP53 mutations. The ability to form compact spheroids or aggregates was observed in six of nine cell lines. Limited ability for migration and anchorage independence was observed. The OV3133(R) cell line, formed tumors at subcutaneous sites in SCID mice. Based on IC50 values and dose response curves, there was clear evidence of acquired resistance to carboplatin for TOV2295(R) and OV2295(R2) cell lines.ConclusionThe study identified nine new high-grade serous ovarian cancer cell lines, derived before and after chemotherapy that provides a unique resource for investigating the evolution of this common histopathological subtype of ovarian cancer.