Differential display and cloning of messenger RNA from human normal nasal epithelial cells versus nasopharyngeal carcinoma cell lines.

Carcinogenesis is a multi-process event that has been characterized both by activation of cellular oncogenes and by loss of function of tumor suppressor genes. However, no systemic study has been performed to understand the involvement of oncogenes and tumor suppressor genes in the oncogenesis of nasopharyngeal carcinoma (NPC). Differential display was performed to identify genes specifically expressed in normal nasal epithelial cells or NPC cell line HONE-1. Using Ltk3 and T11CA as primers, a 379-bp cDNA fragment (CN3) obtained from normal nasal epithelial cells was able to show specificity by northern blot analysis. A 3.5-kb mRNA was detected in normal nasal epithelial cells but not in NPC cell line HONE-1 by using 32P-end-labeled CN3 fragment as a probe. Sequence analysis of the 379 bp cDNA fragment indicated unique sequences from nts 1 to 230. Nts 231 to 379 are Alu-like sequences. Northern blot analysis using 32p-labeled PCR product amplified from nts 36 to 222 of CN3 cDNA fragment was also able to detect the 3.5-kb mRNA in normal nasal epithelial cells but not in HONE-1 and two other NPC cell lines NPC-TWO1, NPC-TWO4.