OBJECTIVETo study the inhibitory effect of chlorophyllin (CHL) on trans-benzo(a)pyrene-trans-7,8-dihydrodiol-9,10-epoxide (BPDE) induced malignant transformation in human bronchial epithelial cell line (16HBE).

METHODS10, 50 or 100 micro mol/L CHL were added into the media during the cells transformation induced by BPDE, and the malignant degree of transformed cells were identified by the ConA agglutination test and the assay for anchorage-independent growth and tumorigenicity.

RESULTSAfter the cells were cultured for 25 times, the time of cells agglutination in groups treated with both CHL and BPDE was increased significantly; the colony formation efficiency in soft agar in groups treated with both CHL and BPDE (7.4 per thousand, 11.4 per thousand and 14.4 per thousand ) showed significant decrease (P < 0.05) in dose-dependent manner, as compared with that in group treated with BPDE alone (19.6 per thousand ). Cells treated with both CHL and BPDE or BPDE alone developed tumor in nude mice, a squamous carcinoma confirmed by histopathological examination. The volume of tumor in groups treated with both CHL and BPDE (0.43 +/- 0.13) cm(2), (0.22 +/- 0.04) cm(2) and (0.10 +/- 0.06) cm(3) was significantly smaller (P < 0.05) and dose-dependent, as compared with that in the group treated with BPDE alone (1.71 +/- 0.37) cm(3).

CONCLUSIONCHL showed significant antitransforming ability in human bronchial epithelial cell line induced by BPDE.