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.

Project description:The fallopian tube epithelium is one of the potential sources of high-grade serous ovarian cancer (HGSC). The use of estrogen only hormone replacement therapy increases ovarian cancer risk. Despite estrogenâ??s influence in OVCA, selective estrogen receptor modulators (SERMs) typically demonstrate only a 20% response rate. This low response could be due to a variety of factors including the loss of estrogen receptor signaling or the role of estrogen receptor signaling in different potential cell types of origin. The response of fallopian tube epithelium to SERMs is not known, and would be useful when determining therapeutic options for tumors that arise from this cell type, such as high-grade serous cancer. Using normal murine derived oviductal epithelial cells (mouse equivalent to the fallopian tube) estrogen receptor expression was confirmed and interaction with its ligand, estradiol, triggered mRNA and protein induction of progesterone receptor (PR). The SERMs 4-hydroxytamoxifen, raloxifene and desmethylarzoxifene, functioned as estrogen receptor antagonists in the oviductal cells. Cellular proliferation and migration assays suggested that estradiol does not significantly impact cellular migration and increased proliferation in CD1, but not in FVB derived cell lines. Further, using RNAseq, the oviduct specific transcriptional genes targets of estrogen and 4-hydroxytamoxifen signaling were determined and validated. The RNA-seq revealed enrichment in proliferation, anti-apoptosis, calcium signaling and steroid signaling processes. Finally, the ER and PR receptor status of a panel of HGSC cell lines was investigated highlighting the need for better models of estrogen responsive HGSC cell lines. Murine oviductal epithelial cells from the FVB background were hormone starved for 48 hours (with a media change after 24 hours), then treated in triplicate with solvent control (DMSO) (0.1%), 1 nM 17-betaestradiol or 100 nM 4-hydroxytamoxifen for 24 hours. Following treatment, RNA was was isolated, libraries were prepped and sequenced using the Illumina HiSeq 2500 platform.

Project description:We treated 6-8 week old mice that had floxed alleles of both Apc and Pten (for both alleles in each case) that also carry an Ovgp1-iCre-ERT2 transgene, with one of two treatments; a third group received neither treatment. The Ovgp1-iCre-ERT2 expresses Cre recombinase fused to a tamoxifen-inducible fragment of the estrogen receptor, in tissues where the Ovgp1 gene (oviductal glycoprotein 1) is expressed, which is almost exclusively in mouse oviductal epithelium (equivalent to human fallopian tube epithelium = FTE). Treating the mice with tamoxifen permits the Cre recombinase to enter the cell nucleus and inactivate the Apc and Pten genes. Six of the mice were treated with intraperitoneal injection of tamoxifen (0.1g/kg of body weight) dissolved in corn oil on days 1 and 3 and developed oviductal tumors (OdT) yielding 6 of the samples. Four mice (yielding 5 samples) were instead injected with 50 million plaque-forming units of replication-incompetent AdCre into both ovarian bursal cavities on day 1, which inactivated Apc and Pten in the ovarian surface epithelium (OSE), and lead to ovarian tumors (OT). Ovaries were also harvested from four untreated 6-8 week old mice with the same genotype, with two ovaries from each mouse comprising one control sample. RNA was purified from tumor or normal tissue, and targets for Affymetrix arrays synthesized from the mRNAs. We used Affymetrix Mouse Gene 2.1 ST arrays, which hold 41345 probe-sets, but we largely analyzed just those 25216 probe-sets that were mapped to Entrez gene IDs. Raw data was processed with Robust Multi-array Average algorithm (RMA). Data is log2-transformed transcript abundance estimates. We fit a one-way ANOVA model to the three groups of samples. We supply a supplementary excel workbook that holds the same data as the data matrix file, but also holds the probe-set annotation at the time we analyzed the data, and some simple statistical calculations, which select subsets of the probe-sets as differentially expressed. Consumers should consider obtaining more up-to-date probe-set annotation for the array platform. We also provide supplementary excel files that show our simple analysis of GSE6008, which consists of 99 human ovarian tumor samples of 4 types, and 4 normal ovary samples, where we fit an ANOVA model to the 5 groups. In yet another supplementary file we show the correlation between each human tumor and mouse tumor, where we correlate the difference in log2-transformed values of each tumor from the average of the normals for the same species, for just those genes that were 1-to-1 best homologs according to build 68 of NCBI's Homologene, in order to see how much the human tumors resemble the mouse tumors. Six oviductal tumor samples from 6 mice with conditional knockout of Apc and Pten driven by an Ovgp1-iCre-ERT2 transgene , 5 ovarian tumor samples from 4 mice with conditional knockout of Apc and Pten driven by injection of AdCre into both ovarian bursal cavities, and 4 normal ovary samples from 4 mice.

Dataset Information

PTEN loss in the fallopian tube induces hyperplasia and ovarian tumor formation

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure