[Mapping and expression analysis of a different expression cDNA fragment from lung adenocarcinoma cell line]

Lung cancer is one of the most common malignant tumors in humans. Metastasis is the basic biological feature of malignant tumors, which is the main cause of death. Molecular mechanism of metastasis is still unclear, although lots of studies have been done in tumor metastasis. To study and explore the molecular basis of metastasis in lung cancer, and isolate tumor metastasis-related genes, two human lung adenocarcinoma cell lines AGZY 83-a and Anip 973 were chosen as research materials. The Anip973 was derived from AGZY83-a, but manifested much higher metastasis potential than the parent line. Using mRNA differential display technique, an unknown cDNA fragment, OPB7-1, which is over-expressive in Anip973 cell line, was obtained. It was used as a template to isolate its corresponding cDNA through dbEST searching and PCR. To search and clone lung adenocarcinoma metastasis-related candidate gene, and to explore the molecular basis of development of lung carcinoma, differential expression of OPB7-1 cDNA fragment among 9 human lung adenocarcinoma cell lines and 12 normal human tissues were detected using cell culture, cDNA clone, Northern blot analysis and bioinformation technology. Results showed that there were significant differences in OPB7-1 expression among 9 human lung adenocarcinoma cell lines. High expression tendency was observed in Anip973 cell line with high metastasis potential, TKB-18 cell line with high invasion potential and GLC-82 cell line with low differentiation potential. Besides, a bigger fragment can be found in Anip973 cell line on the Northern blot hybridization. The 3.0 kb transcriptions were found in various tissues. Over-expression in heart and skeletal muscle could be observed, whereas expression in spleen, liver, kidney, placental and lung could be found except colon, thyroid gland and small intestine. These manifests indicate that OPB7-1 gene has a wide-rage expression in human multiple tissues. A 1.0 kb cDNA fragment was acquired by linking up EST fragments homologous match 5' end and PCR. BLAST analysis revealed that OPB7-1 gene has extremely low sequence identity with any known genes from GenBank and any sequences from EST database. The chromosomal localization of it was determined by RH location method. The OPB7-1 fragment was localized to chromosome 1p31-34. That OPB7-1 gene has an extensive expression pattern, may be a novel tumor gene related to lung carcinoma. Further research needs to be done to obtain the full-length cDNA of OPB7-1 gene. It will be helpful to investigate the expression in lung cancer cases and other tumor tissues for further determining the function of OPB7-1 gene in development of tumor.