OBJECTIVETo 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.

METHODSThe 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.

RESULTSP110 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.

CONCLUSIONSP110 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.