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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-1a (SDF-1a) 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-1a 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-1a 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-1a 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-1a on Ishikawa-PTEN cells growth was markedly less than the effect on Ishikawa-neo and Ishikawa cells. However, in the absence of SDF-1a 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 level of pAKT but not pERK in Ishikawa-PTEN cells. PTEN protein may suppress the growth-promoting effect of SDF-1a on endometrial carcinoma by inhibiting the PI-3K/AKT signal transduction pathway.LI Xiao-ping, ZHAO Dan, GAO Min, ZHAO Chao, WANG Jian-liu and 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-1a (SDF-1a) 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-1a 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 prote in 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-1a stimulation were 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-1a 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-1a on Ishikawa-PTEN cells growth was markedly less than the effect on Ishikawa-neo and Ishikawa cells. However, in the absence of SDF-1a stimulation The was 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 level of pAKT but not pERK in Ishikawa-PTEN cells. PTEN protein may suppress the growth-promoting effect of SDF-Ia on endometrial carcinoma by inhibiting the PI-3K / AKT signal transduction pathway. LI Xiao-ping, ZHAO Dan, GAO Min, ZHAO Chao, WANG Jian-liu and WEI Li-hui