[Effects of wild type PTEN gene on proliferation, apoptosis and the influence on apoptosis key factor Bcl-2 and Caspase family on K562 cells].

OBJECTIVE: To investigate the effect of tumor-suppressing gene,wild type PTEN gene, mediated by adenovirus vector on the cell proliferation, apoptosis and the influence on apoptosis key factor Bcl-2 and Caspase family on human chronic myeloid leukemia (CML) cell line K562 in vitro. METHODS: The recombinated Ad-PTEN gene containing green fluorescent protein gene (Ad-PTEN-GFP) or the empty vector (Ad-GFP) was transfected into K562 cells. The growth of K562 cells was evaluated by MTT assay; the transfection efficiency of Ad-PTEN-GFP, apoptosis rate and proliferation index (PI) were assessed by flow cytometry (FCM). Morphological characteristics of transfected cells under light and transmission electron microscope were applied to demonstrated the apoptosis; DNA ladder and fluorescent staining were also tested; the PTEN, Bcl-2 mRNA levels were detected by real-time fluorescent relative-quantification reverse transcriptional PCR (FQ-PCR); PTEN and Bcl-2 protein levels were detected by Western Blotting; and Caspase-3/7 and -9 protein activity were detected by corresponding kits. RESULTS: The 200 multiplicity of infection (MOI) of Ad-PTEN-GFP was applied to transfect K562 cells. The maximum growth inhibiting ratio was 37.1%. The early and advanced apoptosis rates were higher than Ad-GFP group and untransfected group (P<0.05). After 3 days transfaction of PTEN gene the Bcl-2 mRNA and protein were 0.27 fold and 0.58 fold respectively; and the Caspase-3/7 and -9 protein activity increased in time-depentend manner after transfected with PTEN gene at the first 3 days compared with Ad-GFP group and untransfected group. CONCLUSION: Over expression of PTEN gene can inhibit K562 cells proliferation and promote cell apoptosis probability via inhibiting Bcl-2 expression and up-regulating the Caspase-3/7 and -9 ability.