As the relevance of Src in inducing caveolin 1 was evident, Src phosphorylation was blocked by SU6656 and cells had been subsequently treated with TGF B. As shown in Figure 6D, TGF B decreased caveolin 1 expression in controls. SU6656 also impacted caveolin 1 expression compared to untreated controls. When TGF B and SU6656 have been combined, no additive effect on expression was detectable. These findings argue to get a dominant role in the Smad pathway on caveolin 1 repression, capable of overruling the Src axis. We thus conclude that TGF B will not be in a position to induce caveolin 1 in nor mal epithelial hepatocytes. TGF B induces caveolin 1 in low caveolin 1 expressing HCC cell lines Caveolin 1 has been linked to cancer, such as HCC. A number of studies correlated caveolin 1 expression and prognosis of the patient.
Except one study, selleck enhanced caveolin 1 levels have already been linked to poor prognosis. Six HCC cell lines, namely Hep3B, HUH 7, PLC PRF five, FLC four, HLE and HLF, were screened for caveolin 1 expression and we located marked differences on both mRNA and protein level. Previously, Hep3B, HUH 7 and PLC PRF 5 were classified as differentiated and HLE and HLF as dedifferentiated HCC cell lines. Noteworthy, FLC four cell line has an epithelial pheno type and was reported to demonstrate hepatocyte like functions. On the other hand, these cells exhibit elevated basal mi gration capacity and have undergone the E to N Cadherin switch. According to these observations, FLC 4 were assigned as dedifferentiated with each other with HLE and HLF cells. Contemplating the tumor promoting function of TGF B in HCC, the cell lines had been analyzed for TGF B regula tion of caveolin 1 expression.
Interestingly, low expressing cell lines respond to TGF B stimulation with considerable upregulation of caveolin 1 expres sion on mRNA level. Similar results have been obtained on protein level, despite the fact that the kinetics of upregulation differed. As the low selleckchem P450 Inhibitor expressing cell lines show a additional differentiated phenotype, as when compared with the high expressing ones, it might be hypothesized that TGF B mediated cancer EMT is accompanied with an increase of caveolin 1 expres sion. As a consequence of the implications of your FAK Src axis on caveolin 1 expression, Hep3B had been treated with PP2 or PF573228 to inhibit Src and FAK phosphorylation and subsequently sti mulated with TGF B1 for 24 h. Blocking of Src FAK affected caveolin 1 induction.
To conclude, low caveolin 1 expressing HCC cell lines induce its expression upon TGF B challenge via a FAK Src dependent pathway. Discussion Hepatocyte dedifferentiation in collagen monolayer cul ture is a main obstacle for toxicity screening. Throughout culture, hepatocyte metabolic functions are altered resulting from downregulation of metabolic enzymes including the broad loved ones of Cyp enzymes. Polarity establish ment and upkeep are essential processes to regulate hepatocyte function and hence in focus of study.