OBJECTIVETo study the effect of exogenous caveolin-1 on the growth of laryngeal squamous cell carcinoma and its mechanisms.

METHODSEukaryotic expression vectors containing human caveolin-1 gene were transfected into Hep-2 cell line, the positive clones with high expression of caveolin-1 were identified by fluorescence quantitative real time reverse transcriptase-polymerase chain reaction and Western Blot. Cell proliferation viability was tested by methyl thiazolyl tetrazolium assay, the protein expression of epidermal growth factor receptor (EGFR), P-EGFR, extracellular signal-regulated kinase 1, 2 (Erk1, 2), P-Erkl, 2 and caveolin-1 were detected by Western Blot. The combination of caveolin-1 and EGFR were studied by immunoprecipitation and Western Blot. The in vivo antitumor activity of caveolin-1 was tested in Hep-2 xenograft tumor models in athymic nude mice, and the protein expressions of P-EGFR, P-Erk1, 2 and caveolin-1 were examined by immunohistochemistry.

RESULTSThree of caveolin-1 stably transfected Hep-2 cell clones were established. MTT assay showed that the proliferation of caveolin-1 overexpression Hep-2 cell clones decreased significantly comparing with the control. Immunoprecipitation and western Blot showed that caveolin-1 and EGFR were combined in Hep-2 cell line. Comparing with the parental cell line and cells transfected with control vector, there were the lower phosphorylation of EGFR and Erk1, 2 in the caveolin-1 overexpression Hep-2 cell clones. In the xenograft tumor models in nude mice, caveolin-1 overexpression Hep-2 cell clones showed the slower growth, smaller tumor size and the lower phosphorylation of EGFR and Erk1, 2.

CONCLUSIONSOverexpression of caveolin-1 inhibits growth of Hep-2 cell line in vitro and in vivo, arresting EGFR-MAPK signal pathway may involve in its mechanism.