[Preliminary study on differentiation-inducing associated genes of human brain glioma cells in vitro].

BACKGROUND & OBJECTIVE: Glioma cells can be induced in vitro from low differentiation state to high differentiation state with differentiation-inducing agents, as our previous studies have showed. However, the relevant molecular mechanisms remained unclear. This paper was to establish differentiation-inducing gene expression pedigree of glioma cells and clone new relevant genes, for the purpose of offering genomic information on the molecular mechanisms of differentiation-inducing effects of tumor cells. METHODS: A low differentiated human brain glioma cell line (SHG-44-9) was treated with differentiation-inducing agents. The differentiation-inducing effects on glioma cells were determined using MTT assay, colony-forming efficiency in double-layer soft agar, cell morphological changes, flow cytometry, and fluoroimmunoassay of glial fibrillary acidic protein expression. Gene expression differences of tumor cells before and after inducing were assayed with cDNA microarray techniques. The relevant genes were cloned with differential display polymerase chain reaction (DD-PCR), and verified with Northern blot analysis, then the genomic information about these genes were analyzed with bioinformatics technologies. RESULTS: At dose of 1.75 mmol x L(-1), sodium butyrate caused a marked proliferation inhibitory effect on the SHG-44-9 cells, and drove them to a more mature phenotype. The expression of 98 genes changed obviously when were screened with gene chips immobilized with 18,000 human cDNAs, which were further proved by Northern blot analysis. Twelve differentiation-associated genes were cloned, including MIBP1 gene, which can regulate the c-myc gene expression and may be relevant with glioma cell differentiation. CONCLUSION: Ninety-eight genes associated with differentiation and 12 genes were cloned. These data may help to further study the molecular mechanisms of glioma cells differentiation, and to find new targets for gene therapy against glioma.