Epithelial-mesenchymal Transition In Ovarian Cancer Cells Research Articles

Follicle-stimulating hormone induced epithelial-mesenchymal transition of epithelial ovarian cancer cells through follicle-stimulating hormone receptor PI3K/Akt-Snail signaling pathway.

It has previously been shown that follicle-stimulating hormone (FSH) and its receptor contribute to epithelial ovarian cancer (EOC) development. Epithelial-mesenchymal transition (EMT) is the early event of metastasis in cancer. Therefore, the aim of this study was to investigate the roles of FSH and the FSH receptor (FSHR) in EMT of EOC. Ovarian cancer cells treated with various doses of FSH were used to investigate the effect of FSH on EMT. Small interfering RNA-mediated FSHR depletion or reexpression of FSHR by acute transfecting pcDNA-hFSHR plasmid was performed to determine the role of FSHR in FSH-induced EMT. Moreover, LY294002, a potent and specific cell-permeable inhibitor of phosphatidylinositol 3-kinases (PI3K), was selected to pretreat ovarian cancer cells to confirm whether PI3K/Akt signaling is involved in this event. In the current study, FSH was found to induce the phenotypes of EMT including migration and invasion in EOC cells. Elevated FSHR levels promoted EMT, migration, and invasion, whereas small interfering RNA-mediated FSHR knockdown inhibited these processes. Moreover, the inhibition of FSH-induced PI3K/Akt signaling pathway attenuated Snail expression and the EMT process. Collectively, the findings of the current study indicate that FSH induced the EMT of ovarian cancer cells through the FSHR-PI3K/Akt-Snail signaling pathway.

Ginsenoside 20(S)-Rg3 targets HIF-1α to block hypoxia-induced epithelial-mesenchymal transition in ovarian cancer cells.

The prognosis of patients with ovarian cancer has remained poor mainly because of aggressive cancer progression. Since epithelial-mesenchymal transition (EMT) is an important mechanism mediating invasion and metastasis of cancer cells, targeting the EMT process with more efficacious and less toxic compounds to inhibit metastasis is of great therapeutic value for the treatment of ovarian cancer. We have found for the first time that the ginsenoside 20(S)-Rg3, a pharmacologically active component of the traditional Chinese herb Panax ginseng, potently blocks hypoxia-induced EMT of ovarian cancer cells in vitro and in vivo. Mechanistic studies confirm the mode of action of 20(S)-Rg3, which reduces the expression of hypoxia-inducible factor 1α (HIF-1α) by activating the ubiquitin-proteasome pathway to promote HIF-1α degradation. A decrease in HIF-1α in turn leads to up-regulation, via transcriptional suppression of Snail, of the epithelial cell-specific marker E-cadherin and down-regulation of the mesenchymal cell-specific marker vimentin under hypoxic conditions. Importantly, 20(S)-Rg3 effectively inhibits EMT in nude mouse xenograft models of ovarian cancer, promising a novel therapeutic agent for anticancer therapy.

HTERT mediates norepinephrine-induced Slug expression and ovarian cancer aggressiveness.

Stress hormones have been implicated in both tumor initiation and progression. Human telomerase reverse transcriptase (hTERT) is overexpressed in cancer cells and associated with malignant tumor progression and poor outcome. We thus sought to determine whether the stress hormone norepinephrine (NE) could induce hTERT expression and subsequently ovarian cancer progression. Unexpectedly, NE induced hTERT transcript and protein expression, and subsequently ovarian cancer cell invasion. Pharmacologic inhibition of β2-adrenergic receptor 2 and protein kinase A, as well as silencing of hypoxia-inducible factor-1α and c-Myc expression, profoundly attenuated NE-induced hTERT expression. Strikingly, stimulation of the cells with NE or ectopic expression of hTERT induced expression of Slug, ovarian cancer cell epithelial-mesenchymal transition (EMT) and invasion. Silencing of hTERT expression abrogated NE-induced ovarian cancer cell invasion, EMT and Slug expression. In addition, silencing of Slug expression significantly inhibited NE- and hTERT-induced ovarian cancer cell EMT and invasion. Moreover, continuous exposure to NE was sufficient to enhance in vivo hTERT expression and metastasis of ovarian cancer cells to the lung. Finally, we provide evidence that hTERT links Src to Slug expression in NE-induced ovarian cancer EMT and metastasis. We thus demonstrate a novel role of hTERT in stress hormone-induced ovarian cancer aggressiveness through inducing Slug, providing novel biomarkers and potential therapeutic targets for ovarian cancer.