Novasoy and genistein inhibit endometrial cancer cell proliferation through disruption of the AKT/mTOR and MAPK signaling pathways.

OBJECTIVES: Excess estrogen states, such as those generated by obesity, have long been associated with the development of type I endometrial cancers. Epidemiological studies have linked consumption of isoflavones with a decreased incidence of endometrial malignancy. Thus, our goal was to assess the effect of the isoflavones, novasoy and genistein, on cell proliferation, cell cycle, apoptosis, progesterone receptor (PR) and estrogen receptor-alpha (ERα) expression and the AKT/mTOR and MAPK pathways in endometrial cancer cells. METHODS: The endometrial cancer cell lines ECC-1 and RL-95-2 were used. Cell proliferation was assessed with MTT assay after exposure to novasoy and genistein at varying concentrations. Cell cycle progression was analyzed by flow cytometry. Apoptosis was assessed by flow cytometery for annexin V expression and ELISA for caspase-3 activity. Expression of ERα, PR and hTERT mRNA were evaluated using real time RT-PCR. Western immunoblotting was performed to evaluate the effects of novasoy and genistein on the AKT/mTOR and MAPK signaling pathways. RESULTS: Novasoy and genistein inhibited cell growth in a dose-dependent manner in both cell lines through induction of cell cycle G2 arrest and apoptosis. Treatment with novasoy and genistein decreased hTERT expression in a dose-dependent manner. Genistein decreased ERα mRNA expression while increasing PR expression. Genistein induced phosphorylation of p42/44 in a dose dependent manner in both cell lines but reduced phosphorylation of S6 in only the RL-95-2 cells. CONCLUSIONS: Novasoy and genistein inhibited cell proliferation through varying pathways in different cell lines but included decreased ERα expression and subsequent alteration in the expression of proteins upstream and downstream of the AKT/mTOR and MAPK pathways. Thus, isoflavones may be a promising therapeutic agent in the treatment and prevention of endometrial cancer.

Increased efficacy of metformin corresponds to differential metabolic effects in the ovarian tumors from obese versus lean mice.

Obesity is a significant risk factor for ovarian cancer (OC) and associated with worse outcomes for this disease. We assessed the anti-tumorigenic effects of metformin in human OC cell lines and a genetically engineered mouse model of high grade serous OC under obese and lean conditions. Metformin potently inhibited growth in a dose-dependent manner in all four human OC cell lines through AMPK/mTOR pathways. Treatment with metformin resulted in G1 arrest, induction of apoptosis, reduction of invasion and decreased hTERT expression. In the K18-gT121+/-; p53fl/fl; Brca1fl/fl (KpB) mouse model, metformin inhibited tumor growth in both lean and obese mice. However, in the obese mice, metformin decreased tumor growth by 60%, whereas tumor growth was only decreased by 32% in the lean mice (p=0.003) compared to vehicle-treated mice. The ovarian tumors from obese mice had evidence of impaired mitochondrial complex 2 function and energy supplied by omega fatty acid oxidation rather than glycolysis as compared to lean mice, as assessed by metabolomic profiling. The improved efficacy of metformin in obesity corresponded with inhibition of mitochondrial complex 1 and fatty acid oxidation, and stimulation of glycolysis in only the OCs of obese versus lean mice. In conclusion, metformin had anti-tumorigenic effects in OC cell lines and the KpB OC pre-clinical mouse model, with increased efficacy in obese versus lean mice. Detected metabolic changes may underlie why ovarian tumors in obese mice have heightened susceptibility to metformin.

AMG 479, a novel IGF-1-R antibody, inhibits endometrial cancer cell proliferation through disruption of the PI3K/Akt and MAPK pathways.

Our goal was to evaluate the therapeutic potential of a novel antibody to the insulin growth factor-1 receptor (IGF-1-R; AMG 479) in endometrial cancer cells. The endometrial cancer cell lines, ECC-1/PRAB72 and RL-95-2, were used. Treatment with AMG 479 (0.02-200 nmol/L) resulted in inhibition of cell proliferation at 72 to 120 hours. Insulin growth factor-1 (0.15-7.5 nmol/L) stimulated growth in both cell lines (range of 15%-42%, P = .0025-.0445), which could be blocked by pretreatment with AMG 479 (mean of 29% for ECC-1/PRAB72, P = .006-.007; mean of 36% for RL-95-2, P = .0002-.0045). AMG 479 suppressed IGF-1-R kinase activity in a dose-dependent manner. Cells treated with AMG 479 underwent either G1 (ECC-1/PRAB72) or G2 (RL-95-2) arrest. AMG 479 decreased human telomerase reverse transcriptase (hTERT) mRNA expression in both endometrial cancer cell lines. Treatment with AMG 479 rapidly blocked IGF-1-induced phosphorylation of IFG-1-R, Akt, and p44/42. Thus, manipulation of the IGF-1-R pathway may serve as a promising therapeutic strategy for the treatment of endometrial cancer.