Objective  To study whether rat bone marrow-derived mesenchymal stem cells (BMSCs) obtain tumor characteristics when co-cultured with rat glioma cells by non-contact culture in vitro.   Methods  A co-cultural system was established between rat BMSCs and rat glioma cell line C6 by using 6-well plate and Transwell chamber. Cells were divided into 2 groups

experimental group (co-cultural BMSCs)

and control group (BMSCs cultured alone) .The morphological changes of BMSCs were observed by phase-contrast microscopy. Cell proliferation was determined by the level of nucleostemin (NS) protein. p53 and mdm2 mRNA were examined by real-time quantitative polymerase chain reaction (PCR). The expression of p53 protein and mdm2 protein were detected by Western blotting. The expression and localization of glial fibrillary acidic protein (GFAP) was studied by immunofluorescence staining.   Results  Experimental cell group demonstrated glioma-like cell morphology and expressed GFAP protein. The ability of prolification had no significant change in experimental group compared with control group. p53 mRNA was decreased significantly (P0.01) and the level of p53 protein was increased also (P0.05) in experimental group as compared to those of control group. mdm2 mRNA and mdm2 protein were significantly increased as compared to control group (P0.05).   Conclusion  Certain cytokines of tumor microenvironment can cause rat BMSCs to obtain tumor characteristics

which provides a preliminary experimental basis for the clinical safe application of BMSCs during cancer treatment.