Background Type I gonadotropin-releasing hormone （GnRH-l） agonists have been applied for the treatment of steroid-dependent tumors such as breast carcinoma, ovarian cancer and prostatic carcinoma. But the mechanism has not been clarified yet. There are few reports about the treatment of endometrial carcinoma using GnRH-l agonists. Type II GnRH （GnRH-ll） is a new subtype of GnRH. Our aim was to investigate the effects of GnRH-l agonists and GnRH-ll on estrogen receptor-negative human endometrial carcinoma cells and the effect from phosphatase and tensin homolog gene （PTEN） to them.Methods A lentiviral vector-mediated RNAi method was used to establish a PTEN-negative HEC-1A cell clone （HEC-1A-ND）. MTT and flow cytometry were used to detect the cell proliferation, cell cycle and apoptosis of HEC-1A, HEC-1A-NC and HEC-1A-ND cells after treatment with GnRH-l agonist Triptorelin （10-11 mol/L to 10-5 mol/L） or GnRH-ll （10-11 mol/L to 10-5 mol/L）. Western blotting was used to detect AKT and ERK1/2 activation after treatment with different concentrations of Triptorelin or GnRH-ll for 30 minutes in the above mentioned three kinds of cells. Results Triptorelin and GnRH-ll induced apoptosis and inhibited proliferation of HEC-1 A, HEC-1A-ND and HEC-1A-NC in a dose-dependent manner. This effect was augmented in HEC-1 A-ND cells in which PTEN gene was knocked-down. Furthermore, Triptorelin and GnRH-ll inhibited the AKT and ERK activity in HEC-1 A-ND cells.Conclusions Triptorelin and GnRH-ll can promote apoptosis rate and inhibit cell proliferation of estrogen receptor-negative endometrial carcinoma cells in a dose-dependent manner. PTEN gene can inhibit the effects of Triptorelin or GnRH-ll on human endometrial carcinoma cells.
ZHAO Li-jun LIU Ning LI Xiao-ping WANG Jian-liu WEI Li-hui
Background Mutation or deletion in the phosphatase and tensin homologue deleted on chromosome ten （PTEN） gene has been identified as an important cause of endometrial carcinoma; stromal cell derived factor-1α （SDF-1α） exerts growth-promoting effects on endometrial cancer cells through activation of the PI-3 kinase/Akt pathway and downstream effectors such as extracellular-responsive kinase （ERK）. In this study, a plasmid containing the PTEN gene was transfected into Ishikawa cells to investigate the difference in growth and signal transduction between Ishikawa-PTEN and Ishikawa cells after SDF-1α stimulation, and to study mechanisms of the involvement of PTEN protein in endometrial carcinoma development. Methods Ishikawa cells were transfected with a plasmid （pLXSN-PTEN） containing the PTEN gene and a plasmid （pLXSN-EGFP） with enhanced green fluorescent protein （EGFP）. Cells were then screened to obtain Ishikawa-PTEN cells and Ishikawa-neo cells that can both stably express PTEN protein and EGFP. Expression of PTEN protein, phosphorylation levels of AKT and ERK （pAKT and pERK） and growth differences in Ishikawa-PTEN, Ishikawa-neo and Ishikawa cells before and after SDF-1α stimulation were then determined by Western blots and MTT assays. Results Western blot analysis showed that Ishikawa cells produced PTEN after transfection with the PTEN gene. At 15 minutes after SDF-1α stimulation, the pAKT level of Ishikawa-PTEN cells was lower than that of Ishikawa-neo cells and Ishikawa cells. There was no significant difference in pERK levels among the three cell lines. The positive effect of SDF-1α on Ishikawa-PTEN cells growth was markedly less than the effect on Ishikawa-neo and Ishikawa cells. However, in the absence of SDF-1α stimulation （baseline）, the pAKT level in Ishikawa-PTEN cells was less than that in Ishikawa cells. There was a significant difference in growth between the Ishikawa-PTEN cells and the Ishikawa-neo cells. Conclusions PTEN gene transfection can regulate the le
LI Xiao-ping ZHAO Dan GAO Min ZHAO Chao WANG Jian-liu WEI Li-hui
