Gonadotropins Activate Oncogenic Pathways to Enhance Proliferation in Normal Mouse Ovarian Surface Epithelium

Abstract

Ovarian cancer is the most lethal gynecological malignancy affecting American women. The gonadotropins, follicle stimulating hormone (FSH) and luteinizing hormone (LH), have been implicated as growth factors in ovarian cancer. In the present study, pathways activated by FSH and LH in normal ovarian surface epithelium (OSE) grown in their microenvironment were investigated. Gonadotropins increased proliferation in both three-dimensional (3D) ovarian organ culture and in a two-dimensional (2D) normal mouse cell line. A mouse cancer pathway qPCR array using mRNA collected from 3D organ cultures identified Akt as a transcriptionally upregulated target following stimulation with FSH, LH and the combination of FSH and LH. Activation of additional pathways, such as Birc5, Cdk2, Cdk4, and Cdkn2a identified in the 3D organ cultures, were validated by western blot using the 2D cell line. Akt and epidermal growth factor receptor (EGFR) inhibitors blocked gonadotropin-induced cell proliferation in 3D organ and 2D cell culture. OSE isolated from 3D organ cultures stimulated with LH or hydrogen peroxide initiated growth in soft agar. Hydrogen peroxide stimulated colonies were further enhanced when supplemented with FSH. LH colony formation and FSH promotion were blocked by Akt and EGFR inhibitors. These data suggest that the gonadotropins stimulate some of the same proliferative pathways in normal OSE that are activated in ovarian cancers.

The role of reproductive hormones in epithelial ovarian carcinogenesis

“…Various signaling pathways have been implicated in gonadotropin-induced proliferation, invasion, and metastasis formation in ovarian cancer, such as the RAS/RAF/ MAPK/ERK (Pilarski et al 2012, Hilliard et al 2013, Smolle et al 2013, PI3K/PTEN/AKT/mTOR (Cancer Genome Atlas Research Network 2011, Huang et al 2011, Yamamoto et al 2011, 2012, Carden et al 2012, Abe et al 2013, Dobbin & Landen 2013, and Wnt/ b-catenin signaling pathways (Bodnar et al 2014, Ford et al 2014, Qi et al 2014. Gonadotropin (FSH and LH) receptors share various downstream signaling pathways, including PI3K and MAPK, and consequently, the potential crosstalk between gonadotropins and molecular pathway signaling is of great interest in exploring targeted cancer therapies.…”

PAX2 function, regulation and targeting in fallopian tube-derived high-grade serous ovarian cancer

“…Proliferation was measured using sulforhodamine B (SRB) colorimetric assay and analysis was completed using a Biotek Synergy 2 microplate reader as described previously(15, 51). …”

Mouse Ovarian Very Small Embryonic-Like Stem Cells Resist Chemotherapy and Retain Ability to Initiate Oocyte-Specific Differentiation

“…The potential role of FSH-FSH3 in stem cells with respect to ovarian biology was recently reviewed. 34 Similarly Hillard et al 63 recently reported that FSH increases mouse OSE proliferation through activation of oncogenic pathways in surface epithelial cells. It is likely that in women with POF and high levels of FSH, stem cells may undergo proliferation and initial differentiation.…”

“…Increase in proliferation of OSE in response to FSH or FSH analogs have been shown earlier both in vivo and in vitro. 31,35,[63][64][65][66] Patel et al 31 reported that the sheep ovarian stem cells express FSH receptors and undergo proliferation and clonal expansion in response to FSH via a novel FSHR transcript R3. The potential role of FSH-FSH3 in stem cells with respect to ovarian biology was recently reviewed.…”