Anti-proliferation effect of zoledronic acid on human colon cancer line SW480

To investigate the anti-proliferation effect and mechanism of zoledronic acid (ZOL) on human colon cancer line SW480.

SW480 cells were treated with 0, 12.5, 25, 50, 100 and 200 μmoL/L of ZOL for 48 h, and CCK-8 assay was employed to obtain the survival rate of SW480 cells. SW480 cells were treated with 25 μmoL/L of ZOL for 0, 12, 24, 48 and 72 h, and then the survival rate was obtained. SW480 cells of the ZOL group were treated with 25 μmoL/L of ZOL for 48 h, while cells of the CsA + ZOL group were pretreated with 10 μmoL/L of CsA for 0.5 h and then treated with 25 μmoL/L of ZOL for 48 h. Then the survival rates of SW480 cells of the control group, ZOL group and CsA + ZOL group were determined. Flow cytometry was employed to detect the apoptosis rate and the mitochondrial transmembrane potential (△Ψm) of the three groups and Western blot was used to detect the expressions of cyt C in the cytosol of the three groups.

ZOL inhibited the proliferation of SW480 cells, and the inhibition rate positively correlated with the concentration of ZOL and the action time (P < 0.01). The cell survival rate and the △Ψm of the ZOL group were greatly lower than those of the control group, while the apoptosis rate and the expression of cyt C in the cytosol were obviously higher than those of the control group. All the differences showed distinctly statistical significances (P < 0.01). The cell survival rate and the △Ψm of the CsA + ZOL group were all lower than those of the control group, but substantially higher than those of the ZOL group; while the apoptosis rate and the expression of cyt C in the cytosol were higher than those of the control group, but distinctly lower than those of the ZOL group. All the differences were statistically significant (P < 0.01).

ZOL can induce the apoptosis in human colon cancer line SW480 and then inhibit the proliferation of SW480 cells directly by opening the mitochondrial permeability transition pore abnormally, decreasing △Ψm, and releasing the cyt C into the cytosol. And the effect enhances with the increases of the concentration of ZOL and the action time.