Objective: To observe the growth-inhibitory effect of polypeptide P110, designed with G3BP protein targets, plus cisplatin on human colon cancer HCT-116 cells and mouse colon cancer C26 xenotransplanted tumors in mice.
Methods: The proliferation inhibition of HCT-116 cells and HUVEC cells in vitro was evaluated by MTT assay. A mouse model of xenotransplanted C26 mouse colon cancer was established. The inhibitory effects of P110 and cisplatin at different concentrations on C26 xenotransplanted tumors were assessed.
Results: P110 enhanced the inhibitory effect of cisplatin on proliferation of HCT-116 cells. By treated with 20 µmol/LP110 + 10, 30, 90 µmol/L cisplatin, the proliferation inhibitory rates were (43.3 ± 3.2)%, (46.4 ± 4.6)% and (47.6 ± 5.8)%, respectively, significantly higher than that in the cisplatin group (P < 0.05). 20 µmol/L P110 + 10 µmol/L cisplatin effectively killed HCT-116 cells, whereas with less toxicity to HUVEC cells. The tumor inhibition rates in mice of P110 (25 mg/kg, 50 mg/kg, 100 mg/kg) plus cisplatin (1 mg/kg) were 23.0%, 30.4% and 34.2%, respectively. While, the tumor inhibition rates in mice of the cisplatin group (1 mg/kg) was 22.7%. Compared with cisplatin at the same concentration, the tumor inhibition rates in mice of the P110 plus cisplatin groups were all increased.
Conclusions: P110 can enhance the growth inhibitory effects of cisplatin on HCT-116 cells and C26 xenotransplanted tumors in mice. P110 plus cisplatin can reduce the effective dose of cisplatin and decrease the toxicity of cisplatin.