目的研究Shp-2酪氨酸蛋白磷酸酶对白血病细胞恶性增殖的影响。方法应用W estern b lot和RT-PCR技术分析白血病细胞和正常造血细胞样本Shp-2蛋白和mRNA表达水平;采用反义寡核苷酸技术和流式细胞术分析下调Shp-2表达对白血病细胞增殖与凋亡的影响。结果与正常造血细胞相比,磷酸化Shp-2蛋白在白血病细胞中呈过度表达状态,Shp-2与-βactin比值在白血病组(n=36)、正常骨髓造血细胞组(n=8)及正常外周血细胞组(n=12)分别为1.23±0.74、0.163±0.088和0.034±0.045。同样,Shp-2 mRNA在白血病细胞样本中呈高表达状态,其与-βactin比值在白血病组(n=26)和正常造血细胞组(n=25)分别为1.242±1.057和0.046±0.076。用Shp-2特异性反义寡核苷酸阻断Shp-2表达后,白血病细胞出现明显凋亡和生长抑制。结论Shp-2在人白血病细胞中呈过度表达状态,其表达水平可能与白血病细胞增殖程度密切相关。
Abstract:Objective To study the structure and function of a novel serine protease gene associated with human colorectal cancer SNC19.Methods The cDNA sequence was determined by both manual and automatic sequencing techniques. The full length cDNA sequence was obtained by the 5'-Rapid Amplification of cDNA Ends technique and web-based analysis. Open reading frame analysis and protein function prediction were also performed. Northern blot was used to detect the expression of SNC19 in various human normal tissues and tumor cell lines. Fluorescent in situ hybridization combined with fluorescent R-banding technique was employed to map the SNC19 gene on human chromosome.Results Full length SNC19 cDNA, size 3152 bp, encodes a protein highly homologous to a mouse serine protease epithin. In normal human tissues, high SNC19 expression levels were observed in the kidney, pancreas, prostate, small intestine and colon; moderate SNC19 expression levels were observed in the placenta, lung, liver, spleen thymus, testis and peripheral blood lymphocytes; and extremely low expression levels were observed in the heart, brain, skeletal muscle and ovary. In tumor cell lines, colorectal cancer cells SW480, SW620, SW1116 and Colo205, breast cancer cell Bcap37 and gastric cancer cells MKN28 and SGC7901 showed high levels of SNC19 expression; cervical cancer cell HeLa-S3, lung cancer PAA, oral epithelial cancer cell KB and lymphoma cell Raji showed moderate levels of SNC19 expression; and tongue squamous cancer cell Tca8113, leukemia cells HL-60, K562, MOLT-4, lung cancer cell A549 and melanoma cell G361 showed very low levels of SNC19 expression. 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 cancer, the expression of SNC19 in various tissues and cell lines may have very important impact on their phenotypes and biological behaviors.
