A novel serine protease SNC19 associated with human colorectal cancer

Objective To study the structure and function of a novel serine protease ge ne associated with human colorectal cancer SNC19. Methods The cDNA sequence was determined by both manual and automatic seque ncing techniques. The full length cDNA sequence was obtained by the 5'-Rapi d Amplification of cDNA Ends technique and web-based analysis. Open reading frame analysis and protein function prediction were also performed. Northe rn blot was used to detect the expression of SNC19 in various human normal tissues and tumor cell lines. Fluorescent in situ hybridization combined wi th fluorescent R-banding technique was employed to map the SNC19 gene on hu man chromosome. Results Full length SNC19 cDNA, size 3152 bp, encodes a protein highly homo logous to a mouse serine protease epithin. In normal human tissues, high SN C19 expression levels were observed in the kidney, pancreas, prostate, smal l intestine and colon; moderate SNC19 expression levels were observed in th e placenta, lung, liver, spleen thymus, testis and peripheral blood lymphoc ytes; and extremely low expression levels were observed in the heart, brain , skeletal muscle and ovary. In tumor cell lines, colorectal cancer cells S W480, SW620, SW1116 and Colo205, breast cancer cell Bcap37 and gastric canc er cells MKN28 and SGC7901 showed high levels of SNC19 expression; cervical cancer cell HeLa-S3, lung cancer PAA, oral epithelial cancer cell KB and l ymphoma cell Raji showed moderate levels of SNC19 expression; and tongue sq uamous cancer cell Tca8113, leukemia cells HL-60, K562, MOLT-4, lung cancer cell A549 and melanoma cell G361 showed very low levels of SNC19 expressio n. SNC19 was mapped to human chromosome 11q24-25. Conclusion SNC19 encodes a novel human serine protease with 855 amino acid residues. As a novel serine protease associated with human colorectal cance r, the expression of SNC19 in various tissues and cell lines may have very important impact on their phenotypes and biological behaviors.