[Correlative study between expression of BRI gene and metastatic potential in human non-small cell lung cancer].

Objective: To investigate the potential relationship between BRI gene expression and metastatic potential in human non-small cell lung cancer (NSCLC).

Methods: Using semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) and Northern blot hybridization techniques, differential expression of the BRI gene in human lung adenocarcinoma cell lines AGZY-83-a and Anip-973 was investigated. Having a much higher metastatic potential, Anip-973 was isolated from AGZY-83-a parental cell line. In addition, the other 6 non-small cell lung cancer cell lines (SPC-A-1, A549, 95D, TKB-18, GLC-82, PAa) and 30 samples of lung cancer tissues with matched corresponding adjacent normal tissues were also analyzed.

Results: There were significant differences in BRI gene expression between the two cell lines. BRI was preferentially expressed in Anip-973 cells compared to its parental cell line AGZY-83-a, and was also up-regulated in the other 6 lung cancer cell lines, correlating possibly with their metastatic potentials. BRI gene over-expression was observed in 30 lung cancer tissues compared with its corresponding adjacent normal tissues. A relative over-expression of BRI mRNA (tumor/normal >or= 2) was observed in 6 of 8 cancer samples with lymph node metastasis and 10 of 22(45.5%) samples without lymph node metastasis. Furthermore, two mRNA transcripts of BRI gene were observed: a 2.0 kb transcript which was mainly observed in normal lung tissues and a 1.6 kb transcript which was present as a dominant species in cancer tissues.

Conclusion: BRI mRNA expression is significantly up-regulated in NSCLC cell lines and clinical tumor samples. An alternatively spliced 1.6 kb mRNA is a major transcript of the gene in NSCLCs, suggesting that differential RNA processing and expression of BRI gene may play a role in the tumorigenesis and/or be related to the metastatic potential of human lung cancer.