Growth and activation of PI-3K/PKB and Akt by stromal cell-derived factor 1alpha in endometrial carcinoma cells with expression of suppressor endoprotein PTEN.
- Author:
Xiao-ping LI
1
;
Dan ZHAO
;
Min GAO
;
Chao ZHAO
;
Jian-liu WANG
;
Li-hui WEI
Author Information
- Publication Type:Journal Article
- MeSH: Cell Line, Tumor; Cell Proliferation; drug effects; Chemokine CXCL12; Chemokines, CXC; pharmacology; Endometrial Neoplasms; pathology; Female; Humans; PTEN Phosphohydrolase; physiology; Phosphatidylinositol 3-Kinases; physiology; Proto-Oncogene Proteins c-akt; physiology; Signal Transduction
- From: Chinese Medical Journal 2006;119(5):378-383
- CountryChina
- Language:English
-
Abstract:
BACKGROUNDMutation 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-1alpha (SDF-1alpha) 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-1alpha stimulation, and to study mechanisms of the involvement of PTEN protein in endometrial carcinoma development.
METHODSIshikawa 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-1alpha stimulation were then determined by Western blots and MTT assays.
RESULTSWestern blot analysis showed that Ishikawa cells produced PTEN after transfection with the PTEN gene. At 15 minutes after SDF-1alpha 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-1alpha on Ishikawa-PTEN cells growth was markedly less than the effect on Ishikawa-neo and Ishikawa cells. However, in the absence of SDF-1alpha 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.
CONCLUSIONSPTEN 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-1alpha on endometrial carcinoma by inhibiting the PI-3K/AKT signal transduction pathway.
