rg-14620 and Endometrial-Neoplasms

Loss or mutation of the PTEN (phosphatase and tensin homologue deleted on chromosome 10) gene is associated with resistance to epidermal growth factor receptor (EGFR) inhibitors. However, the mechanism underlying remains elusive. In this study, we aimed to explore whether sensitivity to the EGFR tyrosine kinase inhibitor (TKI) is affected by PTEN status in endometrial cancer cells. PTEN siRNA and the PTEN gene were transfected into HEC-1A and Ishikawa endometrial cancer cells using lentiviral vectors. Cells were treated under various concentrations of RG14620 and rapamycin, which are EGFR and mammalian target of rapamycin (mTOR) inhibitors, respectively. The IC(50) of RG16420 was determined by using the MTT method. Cell apoptosis and the cell cycle were studied, and activation of EGFR, AKT, and p70S6 were detected by Western blot analysis. Loss of PTEN promoted cell proliferation and led to significant increases in the levels of EGFR, phospho-EGFR, AKT, phospho-AKT, and phospho-mTOR proteins. Ishikawa and HEC-1A(PTENkd) cells that displayed loss and inactivation of PTEN function were resistant to RG14620. HEC-1A and Ishikawa(PTEN) cells with intact PTEN were sensitive to RG14620. The combination of two inhibitors was more effective than both monotherapies, particularly in carcinoma cells with PTEN dysfunction. Decreased phospho-EGFR protein expression was observed in all cell lines that were sensitive to RG14620. Decreased phospho-AKT and phospho-p70S6 protein expression was observed in PTEN-intact cells that were sensitive to RG14620. PTEN loss results in resistance to EGFR TKI, which was reversed by PTEN reintroduction or mTOR inhibitor treatment. The combined treatment of EGFR TKI and the mTOR inhibitor provided a synergistic effect by promoting cell death in PTEN-deficient and PTEN-intact endometrial cancer cells, particularly in PTEN-deficient carcinoma cells with up-regulated EGFR activation.

Topics: Antineoplastic Agents; Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Survival; Drug Resistance, Neoplasm; Drug Synergism; Endometrial Neoplasms; ErbB Receptors; Female; Gene Knockdown Techniques; Green Fluorescent Proteins; Humans; Inhibitory Concentration 50; Phosphorylation; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Recombinant Fusion Proteins; RNA Interference; Sirolimus; TOR Serine-Threonine Kinases; Tyrphostins

To investigate the apoptotic and proliferation effects of signal transduction inhibitors on human endometrial carcinoma cells with different PTEN gene expression.. PTEN antisense oligonucleotide and pcDNA3.1/PTEN vector contained PTEN gene were transfected into endometrial carcinoma cells (HEC-1A and Ishikawa). The expression of PTEN protein was detected by confocal spectral microscopy. The endometrial carcinoma cells (HEC-1A, HEC-1A-PTEN-null, Ishikawa, Ishikawa-PTEN) were treated with signal transduction inhibitors, RG-14620, SB203580 (SB) and rapamycin, respectively. Cell apoptosis morphology, cell apoptosis and cell cycle were detected by Hoechst 33258 staining and flow cytometry. Cell viability was determined by methyl thiazolyl tetrazolium assay.. The PTEN protein expression in two endometrial carcinoma cells (Ishikawa, HEC-1A) was exchanged by PTEN antisense oligonucleotide blocked and pcDNA3.1/PTEN stable transfected. After treated with RG-14620, SB and rapamycin, marked morphological changes of apoptosis were observed in HEC-1A-PTEN-null and Ishikawa cells. The cell apoptosis of HEC-1A-PTEN-null and Ishikawa cells exposed to SB were significantly increase [(31.6 +/- 0.8)% and (37.8 +/- 0.8)%, respectively], the G(1) phase cells were increased to (84.1 +/- 3.2)% and (87.5 +/- 1.9)%. While cell viability was significantly decreased in HEC-1A-PTEN-null and Ishikawa cells, the cell viability of HEC-1A-PTEN-null and Ishikawa cells exposed to SB were (54.0 +/- 2.1)% and (49.0 +/- 1.7)%.. Loss of PTEN in endometrial carcinoma cells may improve the G(1) phase cells and apoptotic effects, inhibit the cell proliferation, which due to the sensitivity of cells to related signal transduction inhibitors.

Topics: Antineoplastic Agents; Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Survival; Endometrial Neoplasms; Enzyme Inhibitors; ErbB Receptors; Female; Humans; Imidazoles; PTEN Phosphohydrolase; Pyridines; Signal Transduction; Sirolimus; Transfection; Tyrphostins