Antitumor effect of cadmium (Ⅱ) complex of pyrazolone derivatives on melanoma B16 cells in vitro and in vivo / 中国药理学与毒理学杂志

ABSTRACT

OBJECTIVE To investigate the antitumor effect of cadmium (Ⅱ) complex of pyrazolone derivatives 1-phenyl-3-methyl-4-propionyl-5-pyrazolone salicyloyl hydrazide-cadmium (Ⅱ) (Cd-PMPP-SAL) on the murine melanoma B16 cells in vitro and in vivo and its mechanisms. METHODS B16 cells were incubated with Cd-PMPP-SAL at 1.0, 1.5, 3.0, 5.0 and 10.0 mg·L-1 for 24, 48 or 72 h. The prolifera? tion rate of B16 cel s was evaluated by MTT assay. B16 cel s were incubated with Cd-PMPP-SAL at 6.25, 12.50 and 25.00 mg·L-1 for 24 h, while cell morphology was observed by Hoechst33258 staining. Apop?tosis of B16 cells was detected by Annexin Ⅴ-FITC/PI staining. The activity of caspases in B16 cells was detected by caspase activity assay. C57BL/6J mice were inoculated subcutaneously with B16 cells to establish a tumor-bearing model. Five days later, Cd-PMPP-SAL at 6.25, 12.50 and 25.00 mg·kg-1 was injected into tumors of C57BL/6J mice once a day for 12 d. The body mass was recorded daily. One day after the last administration, all the mice were killed and the tumor was harvested. Tumor volume and mass were measured, and the tumor inhibitory rates were calculated. Pathological changes of the tumor, liver and lung were observed under a microscope. The expressions of vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF2) in tumor tissues were detected by immuno?histochemistry. The apoptotic cells in transplanted tumor tissues were detected by TUNEL. RESULTS Cd-PMPP-SAL inhibited the proliferation of B16 cells. The IC50 was 4.946 mg · L-1, and 95% confidence interval was 4.24-5.65 mg · L-1. The apoptosis rates(12.8 ± 1.4)% and (18.4 ± 0.4)% of Cd-PMPP-SAL 12.50 and 25.00 mg · L-1 groups were significantly higher than those of control group (1.7 ± 0.1)% (P<0.01). The activity of caspase 3 and 9 of Cd-PMPP-SAL 25.00 mg · L-1 group was significantly higher than that of control group (P<0.01), but there was no significant difference in caspases 3/7. The relative tumor volumes of Cd-PMPP-SAL 6.25, 12.50 and 25.00 mg · kg-1 treated groups from the 8th day of treatment were significantly decreased compared with the model group (P<0.01). The result of paraffin sections showed that the transplanted tumor tissues in Cd-PMPP-SAL 12.50 and 25.00 mg · kg- 1 groups exhibited different degrees of necrosis, but there was no significant pathological damage to the liver or lung tissues of mice. Compared with model group, expressions of VEGF and FGF2 in Cd-PMPP-SAL 12.50 and 25.00 mg · kg-1 treated groups were significantly inhibited (P<0.05), and apoptotic cell rates were significantly higher (P<0.05). CONCLUSION Cd-PMPP-SAL can inhibit growth of B16 cells in vivo and in vitro, which may be associated with induction of tumor cell apoptosis and inhibition of tumor angiogenesis.