[Cloning and sequence analysis of a new, full-length cDNA fragment of drug resistance-related gene in human lung adenocarcinoma].

BACKGROUND & OBJECTIVE: Multi-drug resistance(MDR) is an important cause of chemotherapeutic failure in lung cancer cells. Further studies on drug resistance-related genes in lung cancer by molecular biology techniques will provide keys to inverse MDR of lung cancer. In the present, suppression subtractive hybridization (SSH) is one of the major techniques to clone 494 bp differentially expressed genes. We had found a new drug resistance-related gene fragment, which has 99% homology with the 1316 bp gene sequence BC006151. The BC006151 gene was published in April of 2001 in Genbank, but its function has not been determined yet. This study was designed to clone the full-length cDNA of BC006151 gene and tested the mRNA expression of this gene in several lung cancer cell lines so that to clarify its function and modulation.

METHOD

Primers were designed according to the sequence of BC006151 gene. Using a lung adenocarcinoma MDR cell line SPC-A-1/CDDP, the full-length cDNA of this gene was amplified by RT-PCR and sequence, and the amino acid sequence of protein coded by it was postulated. The mRNA levels of this gene were determined in SCLC cell line SH77, big cell lung cancer cell line H460, lung adenocarcinoma cell line SPC-A-1 and SPC-A-1/CDDP using semi-quantitative RT-PCR assay.

RESULT

The 1298 bp full-length cDNA fragment of BC006151 gene was successfully cloned which has complete reading frame and coding region. The cDNA had very high homology with the 494 bp fragment obtained by SSH. The expression of this gene in MDR cell line SPC-A-1/CDDP was significantly higher than that in its parental cell line SPC-A-1 and it was higher in SPC-A-1 than that in H460, whereas in SH77 this gene was undetectable.

CONCLUSION

The present data suggest that BC006151 gene is a new drug resistance-related gene closely related to MDR of lung adenocarcinoma induced by CDDP. Cloning the full-length cDNA of this gene will be helpful to clarify its role during the occurrence of MDR in lung cancer.