Interaction between missing in metastasis B and caveolin-1 in hepatocellular carcinoma

Objective To investigate the protein interaction between missing in metastasis B (MIM-B) and caveolin-1 in hepatocellular carcinoma (HCC). Methods After the construction of pcDNA3.1 vector carrying the fusion gene of FLAG-MIM-B, we transfected the vectors into Hep3B and SMMC7721 cells respectively. The immunofluorescence and confocal microscopy were applied in detecting distribution of MIM-B and caveolin-1 in MHCC97H cells. The immunoprecipitation in vitro and in vivo was used to confirm the protein interaction between MIM-B and caveolin-1 in Hep3B, SMMC7721 and MHCC97H cells. The cells were divided into empty vector group and FLAG-MIM-B fusion protein group. Results The pcDNA3.1 vector with FLAG-MIM-B fusion gene was successfully constructed and the transfection efficiency of pcDNA3.1-MIM-B-FLAG was over 90%. The results of Western blotting analysis demonstrated that the expression of MIM-B was significantly increased. The results of mass spectrometry showed that MIM-B could precipitate caveolin-1. The confocal microscopy analysis showed that MIM-B was co-localized with caveolin-1. The immunoprecipitation in endo and in exo illustrated the interaction between MIM-B and caveolin-1. Conclusion Our research found that MIM-B and caveolin-1 co-localized and interacted in HCC cell lines, and it is possible to provide a new molecular target therapy for HCC. Key words: Carcinoma, hepatocellular; Missing in metastasis B; Caveolin-1