OBJECTIVETo study the expression and significance of fragile histidine triad (FHIT) and Ki-67 in transformed epithelial cells induced by Yunnan tin mine dust.

METHODSEvery second generation of immortalized human bronchial epithelial cells (BEAS-2B) and human embryo lung fibroblasts (WI-38) were exposed to 100 µg/ml Yunnan tin mine dust for 72 h, until the ninth generation. The cells were subsequently co-cultured from the 11th generation. Experimental setup: B group, B (W) group, B (W 100) group, B100 group, B100 (W) group, B100 (W100) group. The expressions of FHIT and Ki-67 in epithelial cells were determined by the method of immunocytochemistry at the 16th, 26th and 36th generation. The percentage of Ki-67 positive cells was calculated as proliferation index.

RESULTSThe expression of FHIT was observed in BEAS-2B cells. The expression levels of FHIT among B group, B (W) group and B (W 100) group had not instinctive difference. At the 16th generation, the expression of FHIT in the B100 group was decreased compared with that in the B group and the expression of FHIT between B100 (W) group and B100 (W100) group was lower than that in the B100 group. At the 26th generation, the expression of FHIT was decreased compared with that at the 16th generation in the B100, B100 (W) and B100 (W100) groups. However, At the 36th generation, positive expression were observed again in the B100, B100 (W) and B100 (W100) groups and the expression levels were in incremental order. At the 16th, 26th and 36th generation, the proliferation indexes of B group, B (W) group and B (W 100) group were all < 3%. The proliferation indexes of B100, B100 (W) and B100 (W100) were increased step by step with the generation elongation.

CONCLUSIONSFHIT could be a target at which Yunnan tin mine dust induces transformation of BEAS-2B cells. The proliferation activation of BEAS-2B cells can be improved by Yunnan tin mine dust.