Interestingly, IGF I is secreted into follicular fluid by granulosa cells, providing a local source for this cytokine. While it is known that in sulin and IGF are proliferative in immortalized OSE cell lines, it is unknown whether these growth factors may exhibit additional changes in cell growth when the ovary is cultured in three dimensions. By growing normal OSE as a component of ovarian organoids cul tured within alginate hydrogels, the effects of in sulin and IGF on tissue architecture can be determined. The use of alginate hydrogels for organ culture permits growth of tissues in their normal three dimensional architecture without disruption of signaling pathways downstream of extracellular matrix, as can be observed with other culture materials such as Matrigel.
In America, 64% of adult women are considered obese, and this negatively influences reproductive health learn this here now and fer tility. High circulating levels of insulin and IGFs are associated with obesity and diabetes, in the female repro ductive system, increased levels of these growth factors are associated with polycystic ovary syndrome and ovarian cancer. For example, PCOS is a leading cause of infertility that affects 5 10% of reproductive aged women and is diagnosed when patients exhibit at least two of the three following symptoms, anovulation, hyperinsulinemia, and hyperandrogenism. Ovarian cancer is the deadliest gynecological malignancy affecting American women, and obesity and diabetes are associated with a worse prognosis due in part to the effects of elevated levels of insulin and IGF on cancer cells.
Primary cell lines established from ovarian carcinomas demonstrate that the components selleck chemical of the IGF pathway are present in ovarian cancer, including secreted IGF I and IGF II, IGFR I and IGFR II, and IGFBPs. IGF II is overexpressed in ovarian cancer cells compared to normal OSE. IGF signaling exerts a pro proliferative, anti apoptotic effect on ovarian cancer cells and has also been shown to play a role in mediating cisplatin resistance. The current study examines the effects of high insulin and IGF levels on the OSE and ovarian follicles using an alginate hydrogel culture system. High proliferation rates in the OSE following culture with insulin or IGF were observed as described in previous studies, how ever, by utilizing a 3D organ culture system, the present study demonstrates that high levels of insulin and IGF in duce hyperplasia and formation of multiple cell layers in the OSE.
Treatment of organ cultures with the IR IGF1R inhibitor tyrphostin AG1024 restored the OSE to a single layer of epithelium and reduced proliferation to basal rates. Both the MAPK and PI3K pathways were involved in OSE hyperplasia, as small molecule inhibitors for these pathways inhibited insulin or IGF induced hyperplasia and proliferation.