Effects of 4-hydroxytamoxifen, raloxifene and ICI 182 780 on survival of uterine cancer cell lines in the presence and absence of exogenous estrogens.

The impact of 17beta-estradiol and antiestrogens on uterine cancer cells is poorly understood. The aim of this study was to determine the impact of 17beta-estradiol, 4-hydroxytamoxifen, raloxifene and ICI 182 780 on the cell proliferation of six uterine cancer cell lines: HeLa, HEC-1-A, KLE, RL-95-2, Ishikawa and EN-1078D. The effects of these compounds on the cell proliferation of the six uterine cancer cell lines were studied in the presence and absence of estrogens (phenol red and serum deprivation of sex steroids). In a general manner, 17beta-estradiol and 4-hydroxytamoxifen showed similarities in their effects whereas raloxifene showed a different pattern of cell proliferation (agonistic and antagonistic) and ICI 182 780 had antagonistic activity. In the presence and absence of estrogens, we observed that each cell line had diverse expression of ERalpha, ERbeta, GPR30 and REA. GPR30 mRNA expression was significantly reduced in a serum/phenol-free medium. REA mRNA expression was not influenced by the media. Results demonstrated the importance of removing phenol red and the use of deprived serum when studying uterine cancer cells in relationship with 17beta-estradiol and antiestrogens. The affinity of each compound to the binding of ERalpha and ERbeta was very similar with the exception of raloxifene that had a preference for ERalpha binding. Akt phosphorylation/activity was reduced in cells cultured in a phenol red- and steroid-free culture medium indicating that the presence of steroids in the culture media can influence the activity of this survival pathway. Our results suggest that the expression of ERalpha, ERbeta and GPR30 are influenced by sex steroids and might play a role in the response of cells to 17beta-estradiol and antiestrogens but are not the only factors involved in this process.

Resveratrol interferes with AKT activity and triggers apoptosis in human uterine cancer cells.

BACKGROUND: Endometrial cancer is the fourth most prominent cancer among all feminine cancers in the Western world. Resveratrol, a natural anti-oxidant found in red wine emerging as a novel anticancer agent, exerts antiproliferative and pro-apoptotic activity in various cancer cell types, but its effect on uterine cancer cells is poorly understood. At the molecular level, resveratrol has been reported to inhibit cyclooxygenase (COX) expression and/or activity; in endometrial cancer cells, COX-2 is overexpressed and confers cellular resistance to apoptosis. The aim of the present study was to determine if resveratrol could exert anti-proliferative and pro-apoptotic activity over uterine cancer cells upon inhibition of COX-2 expression and/or activity. Six different human uterine cancer cell lines were used as a model (HeLa, Hec-1A, KLE, RL95-2, Ishikawa and EN-1078D). RESULTS AND DISCUSSION: High-dose of resveratrol triggered apoptosis in five out of six uterine cancer cell lines, as judged from Hoechst nuclear staining and effector caspase cleavage. In accordance, uterine cancer cell proliferation was decreased. Resveratrol also reduced cellular levels of the phosphorylated/active form of anti-apoptotic kinase AKT. Endogenous COX-2 protein levels were decreased, concomitant with a decrease in production of COX metabolites PGE2 and PGF2alpha, in each uterine cancer cell line expressing detectable levels of COX-1 and/or COX-2 in presence of resveratrol. Although COX expression was identified as a target of resveratrol in uterine cancer cells, inhibition of COX activity or exogenously added PGE2 did not modulate the effect of resveratrol on cellular proliferation. CONCLUSION: High-dose of resveratrol exerts tumoricidal activity over uterine cancer cells and regulates COX expression. In these cells, resveratrol would not directly target COX activity, but possibly other enzymes involved in prostaglandin synthesis that act downstream of the COXs.

AKT involvement in cisplatin chemoresistance of human uterine cancer cells.

OBJECTIVE: The aim of this study was to investigate the possible involvement of Akt activity and specific isoforms (Akt1, Akt2, and Akt3) in the resistance of human uterine cancer cells to cisplatin. METHODS: Two different endometrial (HEC-1-A and KLE) and one cervical (HeLa) cancer cell lines all known as wild-type PTEN (tumor suppressor phosphatase tensin homologue, a lipid phosphatase involved in the negative regulation of Akt activity) were used for these studies. RESULTS: Basal levels of Akt1, Akt2, and Akt3 mRNAs were determined by real-time quantitative RT-PCR studies and Western blot analyses were carried out to determine protein abundance of each isoforms. Akt1 mRNA and protein were present in all cell lines studied. Akt2 and Akt3 mRNAs and proteins were strongly expressed in KLE cells. Surprisingly, Akt phosphorylation was found in KLE expressing high levels of wild-type PTEN protein. KLE cells remained resistant to PI 3-K inhibitor, indicating that Akt phosphorylation might be, in part, independent of PI 3-K in this cell line. Cisplatin induced apoptosis in HeLa and HEC-1-A cells, but KLE cells expressing Akt2 and Akt3 remained more resistant to cisplatin. Knockout of Akt isoforms using specific siRNA technology increased the sensitivity of KLE cells toward cisplatin and caused a significant induction of cell death. CONCLUSION: Taken together, these results suggest that specific Akt isoforms such as Akt2 and Akt3 might be involved in chemoresistance to cisplatin and that these isoforms could be putative targets for gene therapy in uterine cancers.