Research On The Antitumor Activity And Mechanism Of Action For A Platinum-zoledronate Complex

Objective To explore the antitumor activity of a platinum-zoledronate complex, {[Pt(en)]2ZL}, on various tumor cells, and the possible mechanism of action induced by this compound on human gastric cancer cells SGC7901.Methods The traditional MTT assay and colony formation assay were used to test the effect of{[Pt(en)]2ZL} on the cell viability and proliferation capacity, respectively. The senescence-associated β-galactosidase staining and immunofiuorescence staining were also performed to assess the cell senescence and microtubule polymerization. Fluorescence staining and flow cytometry (FCM) were used to monitor the cell cycle distribution and apoptosis, and western blot was applied to examine the expressions of cell cycle-related and apoptosis-related proteins. Furthermore, small G proteins (Ras, RhoA) were also detected by western blot after the treatment of{[Pt(en)]2ZL}. Supplementary FOH to observe whether the mevalonate pathway involved in antiproliferative effects of{[Pt(en)]2ZL}. In addition, AO fluorescence staining and LC3 protein were detected to observe the activity of cell autophagy induced by {[Pt(en)]2ZL} in SGC7901.Results{[Pt(en)]2ZL} exhibited profound cytotoxic and antiproliferative effects on SGC7901 cells in dose-and time-dependent manners (24 h IC50 70.69±1.08μM,48 h IC50 25.15±0.75μM), and it also induced cell senescence and abnormal microtubule assembly. Cell cycle arrest (G1/S:99.99%) and apoptosis (early apoptosis rate 20.5%, late apoptosis rate 25.3%) induced by{[Pt(en)]2ZL} were observed with FCM and fluorescence staining. The expressions of cell cycle regulators (p53, p21, cyclin D1, cyclin E and CDK2) and apoptosis-related proteins (Bcl-2, Bax, caspase 3, PARP and survivin) were regulated by{[Pt(en)]2ZL} treatment, resulting in the cell cycle arrest and apoptosis. Furthermore, the prenylation on small G proteins (Ras, RhoA) was inhibited by {[Pt(en)]2ZL} in SGC7901 cells. More importantly, FOH could attenuate the extents of cell cycle arrest (G2/M:9.17±1.12%), cell apoptosis (early apoptosis rate 6.12±3.51%, late apoptosis rate 5.36±0.53%) and the prenylation on small G proteins (Ras, RhoA) induced by {[Pt(en)]2ZL} in SGC7901 cells. In addition, SGC7901 cells exhibited morphological changes related to cell autophagy, and the expression of LC3 protein which played a key role in the progress of cell autophagy was aslo altered after the treatment of {[Pt(en)]2ZL}.Conclusions Our studies have demonstrated that{[Pt(en)]2ZL} possessed an anti-proliferative and cytotoxic activity through arrest of cell cycle, induction of apoptosis and autophagy in human gastric cancer cell line SGC7901. The arrest of G1/S phase was found to be mediated by the alteration in p53-p21-cyclin D branch. Moreover, the apoptotic mechanism may be related with the activation of caspase-3 and the cleavage of PARP. And FOH weakened the pharmacological effects caused by {[Pt(en)]2ZL} in SGC7901 cells. In addition, cell autophagy and the inhibition of prenylation on small G proteins were also induced by{[Pt(en)]2ZL} treatment in SGC7901. Taken together, the complex of{[Pt(en)]2ZL} is a promising anti-cancer drug for treating human gastric cancer...