[Expression of human cytochrome P450 2E1 gene in embryonic nasopharynx, nasopharyngeal cancer cell lines and tissue]

Abstract

Background & objective: Research results in the past suggested that nitrosamines(chemicals) can induce nasopharyngeal carcinogenesis in vivo and in vitro. As the indirect carcinogens, their activation are mainly dependent on cytochrome P450 2E1. The study here was to investigate the roles of human cytochrome P450 2E1 (hCYP 2E1) gene in chemical cancinogen-induced nasopharyngeal carcinogenesis, and to provide new evidence about etiology and pathogenesis of nasopharyngeal carcinoma(NPC).

Methods: RT-PCR were used to detect the expression of CYP2E1 in 8 embryonic nasopharyngeal epithelial tissues(ENET), 10 NPC biopsys, 5 NPC cell lines(CNE-1, CNE-2, HNE-1, HNE-2, and HNE-3), 1 transformed nasopharyngeal cell line(7429) and 3 human embryonic nasopharyngeal epithelial(HENE) cell lines treated with 200, 250, and 300 micrograms/ml of chemical carcinogen N, N'-dinitrosopiperazine(DNP) in vitro for 24 h, respectively.

Results: (1) All of ENET(8/8), NPC cell lines(6/6, including 7429 cell line) and 80% of NPC biopsys(8/10) showed expression of hCYP2E1; (2) The hCYP 2E1 expression in HENE cell lines was elevated after treatment with different concentration of DNP.

Conclusion: Human nasopharynx exist inducible CYP2E1 expression, suggesting that hCYP2E1 may play an important role in the course of nasopharyngeal carcinogenesis caused by indirect carcinogens nitrosamines(such as DNP).