The Proliferation Inhibit Of Rat Pituitary Adenoma GH₃Cells By Temozolomide And Its Mechanism Study

ObjectiveTo study the effete of temozolomide on Proliferative and apoptosis of Ratpituitary adenoma GH₃cells and explore the related machanisms.MethodsAll cells used in the following trials were in logarithmic growth phase.MTTassay was carried out to observe the anti-Proliferation effect of different concentrati-ons of temozolomide （50,100,200,250,500μmol/L）on GH₃cells at the time Point of24,48and72h. And the half-maximal inhibitory(IC₅₀) of temozolomide concentrationof was calmulated. The cell cycle of GH₃cells treated with indicated temozolomide(IC₅₀) for24and48hours were analyzed by flow cytometry. The apoptotic rates ofGH₃cells treated with different concentrations of temozolomide for24hours wereanalyzed by Tunel staining. The expression of bcl-2,caspase-3in GH₃cells treatedwith temozolomide (IC₅₀) for0,12,24and48hours were examined by western blot.ResultsMTT assay results demonstrated that temozolomide could inhibit GH₃cellproliferation which depended on the time and concentration of treatmentsignificantly （P<0.05） except for50μmol/L group.The IC₅₀values of temozolomideon GH₃cells at72h was250μmol/L. The data of flow cytometry assay showedtemozolomide could induced s-Phase accumulation and G2/M-Phase arrestcompared to control group （P<0.05）. TUNEL results showed that The apoptoticrates of GH₃cells treated with different concentrations of temozolomide for24hourswas significantly higher compared to control group（P<0.05）.The data of Westernblot showed the expression levels of caspase-3in GH₃cells treated withtemozolomide was up-regulated,while the expression levels of bcl-2and was down-regulated. It was statistically significant compared to control group（P<0.05）.ConclusionsTemozolomide could inhibit the Proliferation of Rat pituitary adenoma GH₃cells in a dose-and time-dependent manner. The mechanisms migh tbe relatedwith induction apoptisis and cell cycle arrest of GH₃cells via mitochondrialPathway. temozolomide may be a new effective treatment for the invasivepituitary adenomas, it is worth further study.