OBJECTIVETo study the malignant transformation of human bronchial epithelial cells induced by glycidyl methacrylate (GMA).

METHODS16HBE cells were treated multiple times with GMA at concentrations of 1, 2, 4 and 8 microg/ml. Cellular biological characteristics of malignant transformation were identified by the tests of conA, colony forming frequency on soft agar, scanning electron microscope and tumorigenesis in nude mice. Test of immunocytochemical detection was also applied to confirm the derivation of cell and tumor. Groups of solvent control (DMSO) and positive control (MCA) were also performed at the same time.

RESULTSTransformed foci could be observed after the cells were treated by GMA at concentrations from 1 to 8 microg/ml. The number of transformation foci increased with the concentration of GMA. Transforming rate in 8 microg/ml group (8.48 x 10(-6)) was significantly higher (P < 0.01) than that of solvent control group (4.5 x 10(-7)). The transformed cells lost contact inhibition and exhibited a crossover growth in culture dish. They also could grow in semi-solid agar and showed dose-reaction relations with the concentration of GMA. The colony forming frequency in 2, 4 and 8 microg/ml group was 1.20 per thousand, 2.35 per thousand and 5.70 per thousand respectively, which were higher than that of solvent control group (P < 0.01). The transformed cells could be agglutinated by low concentration of conA. Microvilli on the surface of transformed cells increased and became strong and long under scanning electron microscope. The transformed cells could form subcutaneous tumor in nude mice which was diagnosed as squamous cell carcinoma in morphology. Expression of cytokeratin (CK) was detected in both 16HBE cells and tumor formed in nude mice.

CONCLUSIONGMA could induce the malignant transformation of 16HBE cells. This research system might provide a potential tool and lay a foundation for the study of the molecular mechanism of carcinogenesis induced by GMA.