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

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

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.

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.

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.