OBJECTIVETo study inhibitory efficacy of combined gene therapy for malignant gliomas transfected with antisense human telomerase reverse transcriptase (hTERT)/PTEN in vitro and in vivo.

METHODSTo construct two adenovirus recons which contained antisense hTERT and wild-type PTEN respectively with high performance homologous recombination system in bacteria. The two adenovirus recons were transfected into U251 human malignant glioma cells combinedly or respectively in vitro and in vivo. U251 cell proliferation in vitro was determined by MTT assay and flow cytometry, tumor growth in vivo was measured by the volume of glioma in nude mice. Telomerase activity was detected by telomeric repeat amplification protocol (TRAP) assay. Expression of hTERT and PTEN protein was detected by Western blotting methods.

RESULTSAfter transfection in vitro, the growth of U251 cells was inhibited significantly. The inhibitory effect was time-dependent. The strongest inhibition was observed in combined transfection group, at the 6th day, the survival rate was 37.6%, telomerase activity (only 28.8TPG) was inhibited significantly, hTERT protein expression was inhibited significantly too, which was 0.2106, but PTEN protein expression was increased significantly, which was 0.9630. In vivo, the growth of tumors was also effectively inhibited.

CONCLUSIONGrowth of malignant glioma cells is effectively inhibited after transfection with combined antisense hTERT and PTEN in vitro and in vivo.