The Mechanisms Of Zoledronic Acid Alone Or Combined With Cisplatin On Proliferation Of Lung Cancer A549 Cells

Objective:1. To investigate the function of Zoledronic acid on proliferation of A549 cells in vitro. 2. To investigate the anti-proliferation and pro-apoptosis effects of different combination of zoledronic acid plus cisplatin upon A549 lung cancer cells in vitro so as to provide the potentially optimal combination of these two drugs.3.To further study the possible mechanisms Zoledronic acid on Lung cancer A549 cells.Methods:1. Groups:(1).Blank control group:single-agent zoledronic acid group, single-agent cisplatin group (2). simultaneous zoledronic acid and cisplatin group (3). the treatment of cisplatin and then zoledronic acid group (4). the treatment of zoledronic acid and then cisplatin group 2.MIT assay,Cell cycle staining solution and Annexin V-FITC/PI double-staining flow cytometry were employed to observe the effects of Zoledronic acid upon anti-proliferation,cell cycle and apoptosis respectively. Colorimetric assay was employed to detect the activity of caspase-3. 3. MIT assay and Annexin V-FITC/PI double-staining flow cytometry were employed to observe the effects of zoledronic acid plus cisplatin upon anti-proliferation and apoptosis respectively,further study detected the activity of caspase-3 by Colorimetric assay.4.RT-PCR was applied to assay mRNA expression of MDC1,ERCC1 and RAP80 among different groups.Results:1.Compared with the control group,the cell proliferation was markedly slowed down in A549 cells when treated with different levels of Zoledronic acid (P<0.05).After 24 hours, Zoledronic acid exterted an S-phase cell cycle arrest and significantly increased the apoptosis percentage of apoptotic on A549 cells( P<0.05 ) .Further study showed that the activity of caspase-3 markedly increased.2.Inhibition of the cell maximal proliferation (46.94±3.45)% and induced the maximal apoptosis (36.53±1.31)% were observed under the treatment of combined zoledronic acid and cisplatin(P<O.05), two drugs have a synergistic effect, such a regimen the treatment of cisplatin and then zoledronic acid was superior to the treatment of zoledronic acid and then cisplatin or simultaneous zoledronic acid and cisplatin (P<O.05). further studies have show that caspase-3 activty in each group were significantly higher than control(P<O.05), although the treatment of cisplatin and then zoledronic acid increased more than the treatment of zoledronic acid and then cisplatin or simultaneous zoledronic acid and cisplatin,but not significant difference(P>0.05).3. The expression levels of MDC1 mRNA and RAP80 mRNA were upregulated on whatever Zoledronic acid or combinated with Cisplatin on Lung Cancer A549 Cells(P<0.05),but the lever of ERCC1 wasnot significant changed.Conclusion:1.Zoledronic acid can significantly inhibit A549 cell proliferation and markedly induce the apoptosis of A549 cells in vitro. Increasing the activity of Caspase-3 maybe one of possible mechanisms. 2. Zoledronic acid and cisplatin in a synergistic way inhibited the cell proliferation and induced apoptosis on lung cancer A549 cell, For the maximal anti-proliferation and apoptosis.A549 cells should be treated with cisplatin then zoledronic acid. Such a regimen provides the optimal scheme for the sequence-dependent treatment.Caspase-3 activity may be involved in the synergistic effect of zoledronic acid and cisplatin.3. The upregulated expression levels of MDC1 mRNA and RAP80 mRNA may invoved in the mechanism of alone and synergistic effect,but ERCC1mRNA maynot.