Immunofluorescence analysis illustrated that nucleus FOXO3a was dramatically decreased in WB-TβLT cells compared with WB-CON cells (Fig. 5C), and it could be restored by overexpression of the dominant-negative mutant of Akt (Fig. 5D), which implies that Akt-mediated exportation and

subsequent degradation of FOXO3a might be, at least partially, involved in LPCs transformation upon TGF-β treatment. More important, overexpression of DN-Akt diminished the proportion of T-ICs (Fig. 5E, Table 1) in WB-TβLT cells and attenuated their self-renewal capacity (Fig. 5F). To clarify how TGF-β regulates the activation of Akt, we determined the PI3K activity in WB-TβLT cells. As shown in Fig. Deforolimus mouse 6A, there selleck compound was no significant difference of PI3K activity between WB-TβLT and the control cells. Interestingly,

WB-TβLT cells with elevated levels of phosphorylated Akt displayed dramatically reduced PTEN expression (Fig. 6B), suggesting PTEN was involved in the activation of Akt. Among the three miRNAs previously reported to suppress PTEN expression,30, 31 the level of miR-216a was obviously up-regulated in WB-TβLT cells compared with WB-CON, whereas miR-217 was only slightly increased and miR-21 remained invariable (Fig. 6C). Mouse-derived liver progenitor cell line (LEPCs) was subjected to long-term treatment with TGF-β and consistent results were achieved (Supporting Fig. 7). Specific antagomir against miR-216a notably rescued PTEN expression and attenuated Akt phosphorylation, whereas down-regulation of miR-217 had a marginal effect (Fig. 6D). Moreover, antagomir-216a evidently reduced the proportion of stem cells in WB-TβLT cells (Fig. 6E, Table 2) and suppressed their self-renewal capacity (Fig. 6F). Suppression of Smad3 by its specific

inhibitor or repression of Smad2 by small interference RNA not only attenuated the up-regulation of miR-216a and down-regulation of PTEN, but also impaired the T-IC characteristics most of WB-TβLT cells (Supporting Fig. 8). Therefore, constant activation of Akt elicited by miR-216a-mediated PTEN suppression is involved in the T-ICs generation from LPCs exposed to TGF-β. TGF-β has been well accepted to be critical in the process of liver fibrosis and cirrhosis. However, the role of TGF-β in HCC occurrence remains elusive.4, 32 With this report we first proposed the association of TGF-β with hepatic T-ICs generation during hepatocarcinogenesis. Our data revealed that TGF-β exposure could induce the transformation of LPCs and give rise to hepatic T-ICs. We also demonstrated that hyperactivation of Akt was required in TGF-β-induced malignant transformation of LPCs. Suppression of PTEN by miR-216a was responsible for Akt hyperactivation in LPCs upon TGF-β exposure.