OBJECTIVETo establish human bronchial epithelial cell lines over expressing oncogene and to investigate its application in detection of carcinogen-induced cell transformation.

METHODSMediated by retrovirus infection, human telomerase catalytic subunit, hTERT was introduced into immortal human bronchial epithelial cells (16HBE) and followed by introduction of the oncogenic allele H-Ras(V12), or c-Myc or empty vector, creating cell lines 16HBETR, 16HBETM and 16HBETV, respectively. Biological characteristics of these cell lines including morphology, proliferation, and chromosomal aberration were examined to access whether they were transformed. Soft agar experiment and nude mice subcutaneous injection were performed using pre-transformed 16HBE cells induced by known carcinogens, nickel sulfate (NiSO4) and 7, 8, -dihydrodiol-9, 10-epoxide benzo[a] pyrene (BPDE).

RESULTSWith detection of telomerase activity and Western blotting, the expression of target proteins was verified. Thus, the transgenic 16HBE cell lines were successfully established. Cells expressing oncogene H-Ras or c-Myc grew 30.3% or 10.4% faster than control cells. However, these cells failed to form colonies in soft agar or form tumor in nude mice. 16HBETR, 16HBETM cells obtained transformed phenotype at 5 wks, 11 wks, respectively after treatment with BPDE, which are 15 wks and 9 wks earlier than control cells 16HBETV (20 wks). Meanwhile, 16HBETR, 16HBETM cells obtained transformed phenotype at 11 wks, 14 wks, respectively after treatment with nickel sulfate, which are 21 wks and 18 wks earlier than control cells (32 wks).

CONCLUSIONWith the advantage of shorter latency, transgenic human cell transformation models could be used in potent carcinogen screening and applied to chemical-carcinogenesis mechanism study.