To investigate the TGFβ1-induced epithelial-mesenchymal transition (EMT) of Huh7 hepatoma cells caused by interaction of hepatitis B spliced protein (HBSP) with transforming growth factor beta-1-induced transcript 1 protein (TGFβ31I1),coding region of HBSP was cloned into lentiviral expression vector.Huh7 hepatoma cells were infected by recombinant lentivirus packaged in 293T cells.Stable cell lines expressing HBSP or control cells were selected by puromycin.Cells were incubated with 5 ng/mL TGFβ1 for 24 h,and observed under contrast-phase microspcope.Then the whole cell lysates were collected for western blot analysis using specific antibodies against EMT markers including E-cadherin,N-cadherin,Claudin-1 and β-catenin.To evaluate the effects of HBSP-TGFβ1I1 interaction on EMT,TGFβ1-induced EMT marker transition,as well as cell invasion and migration were explored after knocking down of TGFβ1I1 by siRNA.Results showed that Huh7 cell lines expressing HBSP (Huh7-HBSP flag-HIV) and control cell lines (Huh7-flag-HIV) were successfully established.Huh7-HBSP flag-HIV cells lost their pebble-like shape and tight cell-cell adhesion and transformed into the mesenchymal-like cells in the presence of TGFβ1.Decreased expression level of epithelial marker of E-cadherin,Claudin-1,β-catenin,increased expression level of mesenchymal marker of N-cadherin,and enhanced migration and invasion abilities were observed in Huh7-HBSP-flag-HIV cells as compared to the control cells.Moreover,the changes of EMT markers and metastasis abilities of Huh7-HBSP-flag-HIV cells could be reversed when TGFβ111 was knocked down by siRNA.In conclusion,HBSP could promote hepatoma cell migration and invasion by triggering EMT via interaction with TGFβ111.Our findings highlight new insights for HBSP-induced HCC progression.