Exogenous
Expression of SOCS Box-deficient Mutant ASB-8 Suppresses the Growth of Lung
Adenocarcinoma SPC-A1 Cells
LIU Yong-Zhong, LI Jin-Jun*, ZHANG Feng-Rui, SHEN Yan1,
YAO Ming, WAN Da-Fang, GU Jian-Ren*
( State
Key Laboratory of Oncogenes and Related Genes, Shanghai Jiaotong University
Cancer Institute, Shanghai 200032, China;
1 Shanghai Research Center of Biotechnology, the Chinese Academy
of Sciences, Shanghai 200233, China )
Abstract ASB-8 is a new member of the human ankyrin repeat and SOCS box containing protein family (ASB). This report deals with the expression of ASB-8 protein in lung carcinoma tissue, as well as its biological effect on the proliferation and growth of lung cancer cell line SPC-A1. ASB-8 was expressed in pT7-450 expression vector, and an anti-ASB-8 rabbit polyclonal antibody was prepared. The expression of ASB-8 protein in lung carcinoma tissue was detected using immunohistochemistry. The growth characteristics of the lung adenocarcinoma SPC-A1 cells expressing either exogenous ASB-8 or ASB-8DSB (SOCS box-deficient) was studied by both in vitro cell growth curve and in vivo nude mouse tumor formation assay. Immunohistochemical staining detected positive reaction of 96.8% (30/31) showing that ASB-8 was highly expressed in lung cancer tissues; however, the expression of ASB-8 was lower, or even no expression in noncancerous lung tissues. Significant growth inhibition was observed in SPC-A1 cell line expressing ASB-8DSB on day 4 and persisted to day 6, compared with mock transfected cells (P<0.01). No difference in the growth properties was observed between ASB-8 and mock transfected cells. In vivo study also showed that tumor formation of ASB-8DSB expressing cells was significantly inhibited as compared with that of the control group (P<0.01). Therefore, ASB-8 may play an important role in growth and proliferation of lung cancer, possibly as positive regulator.
Key words ASB-8 gene; ankyrin repeat; SOCS box; lung cancer
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