The Comparative Study On Proliferation And Apoptosis Of MDA-MB-231 Cells By ～(99)Tc-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: The third passage human breast cancer cell line MDA-MB-231 cells were enzyme-digested and suspended in PRMI-1640 solution. Then adjusted to 5×103/ml and seeded in 96-well microtiter plate and culture bottles in the same concentration and maintained in PRMI-1640 containing 10% FBS in 37℃5%CO2 and allowed to adhere for 24 hours, then cells were treated with different concentrations of 99Tc-MDP and pamidronate equalled culture liquid for 24,48,72 hours. The proliferation of cells was studied by cell counting and methyl thiazolyl tetrazolium ( MTT ) assay .Morphological changes of apoptotic cells were observed by light microscopy. The rate of apoptosis cell cycle and the expression of bcl-2 and bax were observed by flow cytometric assay.Results: Concentration of 50μmol/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%, respectively), and their difference was significant (P< 0.05). Concentration of 50μmol/L 99Tc-MDP and pamidronate could both induce apoptosis of MDA-MB-231 cells. The apoptosis rates were 9.59% and 5.69%, respectively, and their difference was significance (P<0.05). Most of cells were blocked in the G0/G1 phase and S phase. Concentration of 200μmol/L 99Tc-MDP and 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 down regulate the expression of bcl-2 gene. The effect of 99Tc-MDP is stronger than that of pamidronate.