The comparative study on proliferation and apoptosis of MDA-MB-231 cells by 99Tc-MDP and pamidronate

Objective: To observe the influence and difference of cell growth and apoptosis effect of 99Tc-methylene diphosphonic acid (MDP) and pamidronate to human breast cancer cell line MDA-MB-231. Methods: Human breast cancer cell line MDA-MB-231 cells were treated with different concentrations of 99Tc-MDP and pamidronate. The proliferation of cells was studied by cell counting and methyl thiazolyl tetrazolium (MTT) assay. The rate of apoptosis cell cycle and the expression of bcl-2 and bax were observed by flow cytometric assay. Results: Concentration of 50 μmoL/L 99Tc-MDP and pamidronate could both inhibit the proliferation of MDA-MB-231 cells (the 48-hour' s survival rate was 45.9% and 64.0% ), and their difference was significant (P<0.05). Concentration of 50 μmol/L 99Tc-MDP and pamidronate could both induce apoptosis of MDA-MB-231 cells. The apoptosis rates were 9.59% and 5.96%, respectively, and their difference was significant (P<0.05). Most of cells were blocked in the G0/G1 phase and S phase. Concentration of 200 μmol/L 99Tc-MDP and 200 μmol/L pamidronate could both induce apoptosis obviously with expression of bcl-2 gene being down regulated. But the expression of bax gene was no marked regulation. Conclusions: 99Tc-MDP and pamidronate can both induce apoptosis and inhibit proliferation of MDA-MB-231 cells in vitro, and also down regulate the expression of bcl-2 gene. The effect of 99Tc-MDP is stronger than that of pamidronate. (authors)