Mechanism for the Decision of Ovarian Surface Epithelial Stem Cells to Undergo Neo-Oogenesis or Ovarian Tumorigenesis

Abstract

The ovary is surrounded by a whitish layer of mesodermally derived ovarian surface epithelium (OSE) that lines the intraembryonic celom and comprises simple squamous to cuboidal to low pseudostratified columnar epithelial cells. Its integrity is maintained by simple desmosomes, incomplete tight junctions, several integrins and cadherins. Recent research has found that ovarian stem cells (OSCs) exist within the OSE and may be responsible for both neo-oogenesis and ovarian cancer during adult life. The factors determining whether OSCs undergo neo-oogenesis or ovarian cancer are of great interest to researchers and clinicians. Accumulating evidence suggests the mechanism for the decision of ovarian surface epithelial stem cells to undergo either neo-oogenesis or ovarian cancer transformation may comprise both internal and external factors. Here, we review recent progress on how the internal factors, including genes, signaling pathways and lncRNA: OSE stem cells mediate the development and progression of ovarian cancer through various genes such as p53, KRAS, BRAF, and PTEN, and mutations in PIK3CA, and through various signaling pathways, including TGF-B pathway, Wnt signaling pathway, Notch signaling pathway, NF-kB signal transducer and transcriptional activator 3 (STAT3) pathway and Hedghog (HH) pathway. A series of expressions of IncRNA have changed in epithelial ovarian cancer tissues and cell lines compared to normal ovarian tissues and cell lines. As well as external factors, including incessant ovulation, gonadotropin and chronicinflammation: Frequent ovulation, without long-term dormancy, increases the risk of illness, because repeated rupture and repair at the ovulation site provides an opportunity for the accumulation of genetic aberrations; FSH affects all aspects of ovarian cancer metastasis, such as inhibition of apoptosis, through Induction of increased expression of VEGFA (VEGF) to support tumor growth, promote vascular growth, and possibly alter certain oncogenic pathways, thereby promoting proliferation and invasive phenotypic inflammation contributes to tumorigenesis, which help determine whether OSCs undergo neo-oogenesis or ovarian tumorigenesis. Understanding this issue is critical for developing novel strategies for premature ovarian failure and ovarian cancer prevention and therapy.

Keywords: Ovarian cancer; Ovarian stem cells; Ovarian surface epithelium; Premature ovarian failure.