[Exogenous expression of SOCS box-deficient mutant ASB-8 suppresses the growth of lung adenocarcinoma SPC-A1 cells].

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-8 SB (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-8 SB 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-8 SB 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.