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| Effects of signal regulatory proteinα1 on proliferation of hepatocellular carcinoma: a preliminary study |
| Jian-Min Qin, He-Xin Yan, Xing-Wang Wan, Shu-Qin Liu, Jin-Zhang Zeng, Hui-Fang Cao, Meng-Chao Wu and Hong-Yang Wang |
Shanghai, China
Author Affiliations: International Cooperative Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, Second Military Medical University, Shanghai 200438, China (Qin JM, Yan HX, Wan XW, Liu SQ, Zeng JZ, Cao HF, Wu MC and Wang HY)
Corresponding Author: Jian-Min Qin, MD, International Cooperative Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, Second Military Medical University, Shanghai 200438, China (Tel: 86-21-25070856; Fax: 86-21-65566851; Email: jianminqin@yahoo.com) |
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Abstract BACKGROUND: Signal regulatory protein alpha1 (Sirpα1) is a negative regulatory factor, and inhibits receptor tyrosine kinase-dependent cell proliferating signal. This study was undertaken to observe the effect of signal regulatory proteinα1 (Sirpα1)on gankyrin,cyclin D1,CDK4 and Fas expression in Sk-hep1 mouse hepatoma carcinoma cell line.
METHODS: BOSC 23 packed cells were respectively transfected by means of recombinated retrovirus including pLXSN, pLXSN- Sirpα1 and pLXSN- Sirpα1Δ4Y2 with lipofectin, and various plasmid virus media(viral titer 2.1×106 CFU/ml) were collected and infected respectively in 80% confluent Sk-hep1 cells. Transfected Sk-hep1 cells were selectively screened with G418 (1200 μg/ml), and Sk-hep1 cell lines transfected with various plasmids were obtained. The protein expressions of gankyrin, cyclin D1, CDK4 and Fas in various Sk-hep1 lines were determined by Western blotting. Various Sk-hep1 lines were recovered to culture with 10% fetal bovine serum at 12 hours and 24 hours after starving culture with free serum for 72 hours, and cells were collected to determine the percentage of S phase cells of proliferating cycle by flow cytometry.
RESULTS: Sirpα1 transfection remarkably downregulated gankyrin and cyclin D1 expression. Sirpα1Δ4Y2 downregulation of gankyrin expression was greater than that of Sirpα1 (P<0.05), but no significant effect of Sirpα1 and Sirpα1Δ4Y2 on CDK4 and Fas protein expression was observed in transfected Sk-hep1 lines (P>0.05). The percentage of S phase cells significantly decreased in Sk-hep1 cells transfected with Sirpα1 and Sirpα1Δ4Y2 plasmids (vs pLXSN Sk-hep1, P<0.05). The percentage of S phase cells in various Sk-hep1 cells increased when recovering to culture with 10% fetal bovine serum at 12 hours, but the percentage of S phase cells in Sk-hep1 cells transfected with Sirpα1 was the lowest (vs pLXSN and Sirpα1Δ4Y2 Sk-hep1, P<0.05). The percentage of S phase cells in transfected pLSXN Sk-hep1 cells was the largest (vs Sirpα1 and Sirpα1Δ4Y2 Sk-hep1, P<0.05). There was no significant difference between the transfected Sirpα1 Sk-hep1 cells and Sirpα1Δ4Y2 Sk-hep1 cells (P>0.05).
CONCLUSIONS: Sirpα1 decreases gankyrin and cyclin D1 expression, and inhibits proliferation of liver carcinoma cells. It may be one of the forms for an Sirpα1 negative regulation of carcinogenesis and development of hepatocellular carcinoma.
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2005, Vol. 4 
