[Effects of the antibacterial peptide cecropins from Chinese oak silkworm, Antheraea pernyi on 1, 2-dimethylhydrazine-induced colon carcinogenesis in rats].

OBJECTIVE

To gain insight into the putative anticancer effect of the antibacterial peptides, cecropins, from Chinese oak silkworm, Antheraea pernyi, on the cancer cells and 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis in rats.

METHODS

Growth inhibitory effect of the cecropins on normal human gastric epithelial cell line (GES-1) and human colon adenocarcinoma cell line (LS-174T) was observed using a microculture tetrazolium (MTT) colorimetric methods. Male Wistar rats were divided into 4 groups. Group1 was given on a weekly basis cecropins from Antheraea pernyi (3,000 Ua/ml) by gavage at 2 doses of 10 ml/kg body weight and exposed to subcutaneous injection of DMH at the dose of 20 mg/kg body weight. Group 2 was received weekly DMH only. Group 3 was given the cecropins by gavage at the same dose as in group 1. Group 4 was weekly exposed to subcutaneous injection of EDTA (1 mmol/L). All treatments were completed in a course of 18 weeks and the experiment was finished at week 33.

RESULTS

MTT assay showed selective cytotoxic activity of the cecropins against the human colon adenocarcinoma cells line. The viability of the cancer cells was about 54% and 100% for the normal cells. There was a significantly lower incidence of large intestinal tumors in rats gavaged with cecropins (65%, P<0.01), but the tumor burden (tumors/tumor-bearing animal) and tumor mass index were comparable between the groups (P>0.05).

CONCLUSIONS

The cecropins possess effective anti-tumor activity with no cytotoxicity against normal eukaryotic cells, and impede the neoplastic process in murine large intestines.