Project description:The cell-of-origin of high grade serous ovarian carcinoma (HGSOC) remains controversial, with fallopian tube epithelium (FTE) and ovarian surface epithelium (OSE) both considered candidates. Here, by using genetically engineered mouse models and organoids, we assessed the tumor-forming properties of FTE and OSE harboring the same oncogenic abnormalities. Combined RB family inactivation and Tp53 mutation in Pax8+ FTE caused Serous Tubal Intraepithelial Carcinoma (STIC), which metastasized rapidly to the ovarian surface. These events were recapitulated by orthotopic injection of mutant FTE organoids. Engineering the same genetic lesions into Lgr5+ OSE or OSE-derived organoids also caused metastatic HGSOC, although with longer latency and lower penetrance. FTE- and OSE-derived tumors had distinct transcriptomes, and comparative transcriptomics and genomics suggest that human HGSOC arises from both cell types. Finally, FTE- and OSE-derived organoids exhibited differential chemosensitivity. Our results comport with a dualistic origin for HGSOC and suggest that the cell-of-origin might influence therapeutic response.
Project description:In a mouse model of ovarian cancer, we have established that prolonged exposure to 17β-estradiol (E2) accelerates tumour onset and increases the incidence of morphologically dysplastic ovarian surface epithelium (OSE). OSE cell proliferation and morphology are tightly regulated by the asymmetrical distribution of polarity proteins that provide positional cues for surface localization and growth inhibition. We hypothesized that E2 causes OSE dysplasia by inhibiting a tumour suppressor gene called Disabled-2 (Dab2). Dab2 is critical in mediating the polarized distribution of cell surface proteins and is highly expressed in normal OSE, but is absent in the majority of ovarian cancers. In this study, Dab2 is shown to be suppressed by E2 and we investigated the possibility that this occurs through E2 up-regulation of microRNAs. microRNA microarray analysis comparing control vs. E2 treated mouse ovarian cancer cells (MASE) was used to identify candidate miRNAs that have a seeding sequence capable of targeting the 3-prime untranslated region (3’UTR) of both human and mouse Dab2 transcript.
Project description:The hilum region of the mouse ovary, the transitional/junction area between OSE, mesothelium and tubal (oviductal) epithelium is identified as a previously unrecognized stem cell niche of the OSE. OSE cells with high ALDH1 activity have been predominantly detected in the hilum region by immunohistochemical staining. For additional phenotypical characterization, we used microarrays to detail the gene expression profiling between the ALDH1 positive and ALDH1 negative OSE cells. Three independent pools (10 mice each) were analyzed. ALDH1 positive and ALDH negative OSE cells were isolated by FACS and their mRNA used for hybridization onto Affymetrix Mouse Genome 430 2.0 array. Microarray data were analyzed with GeneSifter software. To identify genes significantly altered in ALDH positive population, we performed paired two group analysis with Significance Analysis of Microarrays (SAM) software and visualized with Treeview software.
Project description:Adult Ovarian Surface Epithelium (OSE) retains the ability to undergo Epithelial to Mesenchymal Transition (EMT). We established a cell culture of murine adult OSE in their epithelial state, and we induced EMT by modifying their culture conditions. In this experiment we compare the transcriptional profile of the OSE before and after EMT.
Project description:The hilum region of the mouse ovary, the transitional/junction area between OSE, mesothelium and tubal (oviductal) epithelium is identified as a previously unrecognized stem cell niche of the OSE. OSE cells with high ALDH1 activity have been predominantly detected in the hilum region by immunohistochemical staining. For additional phenotypical characterization, we used microarrays to detail the gene expression profiling between the ALDH1 positive and ALDH1 negative OSE cells.
Project description:Transcriptome profiling using Affymetrix GeneChip arrays was performed on sorted populations of Lgr5-expressing mouse ovarian surface epithelium. The ovary surface epithelium (OSE) undergoes ovulatory tear-and-remodelling throughout life. Resident stem cells drive such tissue homeostasis in many adult epithelia, but their existence in the ovary has yet to be definitively proven. Lgr5 marks stem cells in multiple epithelia. Here we use reporter mice and Single Molecule Florescent-in-Situ-Hybridization (FISH) to document candidate Lgr5+ stem cells within the mouse ovary and associated structures. Lgr5 is broadly expressed during ovary organogenesis, but becomes limited to the OSE in early neonate life. In adults, Lgr5 expression is predominantly restricted to proliferative regions of the OSE and fimbria- mesovarian junction. Using conditional in vivo lineage tracing we identify embryonic and early neonate Lgr5+ populations as stem/progenitor cells contributing to the development of adult OSE and granulosa cell lineages, as well as the epithelia of the mesovarian and oviduct including its distal opening, fimbria. Long-term lineage tracing reveals that adult OSE-resident Lgr5+ populations contribute to epithelial homeostasis and OSE regenerative repair in vivo. Thus, Lgr5 is a marker of stem/progenitor cells of the ovary and tubal epithelia. Ovarian surface epithelium from pooled batches of Lgr5-eGFP-CreERT2 mice (n=8, per array) were sorted for cells expressing either high or low EGFP. Total RNA from three technical replicates per sorted population (Lgr5-high or Lgr5-low) was extracted with the RNeasy Micro Kit (QIAGEN), DNaseI-treated, and amplified with the Ovation Pico WTA V2 (NuGEN Technologies). Single-stranded cDNA amplification products were purified using QIAquick PCR Purification Kit (QIAGEN). cDNA was biotinylated using the Encore Biotin Module (NuGEN Technologies). Biotiylated cDNA was hybridized to Affymetrix Mouse Genechip ST 2.0 expression arrays.
Project description:Our lab established the M0505 cell line from the ovarian surface epithelium (OSE) of FVB/N mice in May 2005 in order to study OSE biology. This cell line spontaneously transformed into the spontaneously transformed OSE (STOSE) cell line in mid 2012. We used microarrays to try to determine the molecular pathways that may have lead to the transformation of M0505 cells into STOSE cells to gain information that may lead to a greater understanding of human ovarian cancer initiation.