Mutant p53 expression in fallopian tube epithelium drives cell migration

Abstract

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 of 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.

Loss of PAX8 in high-grade serous ovarian cancer reduces cell survival despite unique modes of action in the fallopian tube and ovarian surface epithelium

“…Murine oviductal cells (MOE) and murine ovarian surface epithelial cells (MOSE) were obtained from Dr. Barbara Vanderhyden at the University of Ottawa. MOE and MOSE cells were cultured as previously described [34]. OVCAR4 cells were obtained from the National Cancer Institute from the Division of Cancer Treatment and Diagnosis Tumor Repository.…”

“…TCM1204) or empty vector with neomycin resistance as previously described [34]. Cells were plated at low density and treated with 0.15 mg/mL of G418 (Gemini bio-products, Woodland, CA).…”

“…The xCELLigence ® DP system (Acea Biosciences, San Diego, CA) was used to measure migration as previously described [34]. Approximately 4 × 10 4 cells were resuspended in serum free media and plated in the upper chamber of a CIM plate 16.…”

Activin A stimulates migration of the fallopian tube epithelium, an origin of high-grade serous ovarian cancer, through non-canonical signaling

“…A recent retrospective analysis found salpingectomy was associated with a 45% decrease in ovarian cancer risk [7]. Our laboratory has shown that murine oviductal epithelial (MOE) cells stably expressing PTEN shRNA , PTEN shRNA +KRAS G12V , or PTEN shRNA +TP53 R273H colonized the ovary following intraperitoneal xenograft [8,9]. Several transgenic mouse models have also been developed that form fallopian tube-derived tumors that spread to the ovary [10–12].…”

Candidate genes and pathways downstream of PAX8 involved in ovarian high-grade serous carcinoma

“…It is worth noting that it has recently been demonstrated that Fallopian tube secretory cell expansion and the ratio between secretory/ciliated cells (S/C ratio) are linked to pelvic serous neoplasia [91] and in this scenario the cancer cells of the serous tubal intraepithelial carcinoma (STIC) bearing a “p53 signature” invade onto the ovary and implant on peritoneal surfaces [92–94]. During this process, the secretory cells retain the expression of PAX8 that possibly continues to exert its transcriptional activity on its physiological targets and in addition may also function on new targets that become available after the tumorigenic hits (BRCA mutations, p53 signature etc).…”