[Effects of ectopic glial fibrillary acidic protein/green fluorescent protein gene expression on cellular differentiation and proliferation of human glioma cell line].

OBJECTIVE

To investigate the biological effects of ectopic overexpression of glial fibrillary acidic protein (GFAP) in human malignant glioma cell line, and to explore new method of differentiation induction gene therapy for gliomas.

METHODS

A eukaryotic expression vector containing 1.1 kb GFAP cDNA fused with green fluorescent protein (GFP) gene, pIRGFP-GFAP, was transfected into human SHG-44 glioma cell line by lipofectamine. The expression of GFAP/GFP gene and their proteins were detected by fluorescent real-time monitoring, in situ hybridization, Western blot and immunocytochemistry. Flow cytometry, soft agar colony formation and other methods were used to measure the effects of exogenous GFAP expression on cell cycle progression, morphology and growth features of the transfected glioma cells.

RESULTS

The expressions of GFAP mRNA and its protein were markedly increased in SHG-44 cells upon stable transfection with pIRGFP/GFAP vector. Profound morphological changes in these cells were also observed, including the formation of abundant, stellate and thin cytoplasmic processes and a reduction of atypia. Cell proliferation rate and its tumorigenecity on soft agar were markedly reduced. In addition, cell cycle analysis revealed a percentage decrease of cell populations at G0/G1 and G2/M phases.

CONCLUSIONS

Ectopic overexpression of GFAP gene could significantly suppress the growth of SHG-44 malignant glioma cells along with an induction of differentiation. These results imply that forced over-expression of GFAP gene may provide a new strategy for glioma therapy.