[Analysis of differentiation characters in osteosarcoma Mdr sublines]

To explore the relationship between multidrug resistance (Mdr) and malignancy. To observe whether P-glycoprotein (P-gp) overexpression had the same bioactivity as osteogenic stem cell turning into more mature cell or more complex phenotype when parent cell line turned to Mdr phenotype.Six cell sublines of Mdr phenotype with different expression degree were analyzed. Stathmin generally identified in malignancy cell and stem cell, was a microtubule associated protein and the signal of differentiation in osteogenic stem cell. RT-PCR and hybridization in situ were used to analyze the relationship between Mdr1 mRNA and expression of Stathmin mRNA and VEGF mRNA.Morphological and functional analysis of Mdr phenotype showed the P-gp-positive cell lines were more differentiated than the parent cells in terms of enhanced activity of cellular alkaline phosphatase. These subclones all displayed a decrease in potential malignancy such as tumor growth rate and metastatic ability. A significant negative correlation could be identified between Mdr1 mRNA and expression of VEGF and Stathmin mRNA.Expression of Mdr1/P170 indicated osteosarcoma cells differentiated towards more mature state, which will develop the new research field of Mdr and supply the new research method of the function of P- gp.