Fig. 6: PKC pathway is activated in M-HCC cells and necessary for M-HCC survival.
From: Protein kinase C inhibitors override ZEB1-induced chemoresistance in HCC
a The expression of different PKC family proteins and PKC activity was investigated in a panel of HCC cell lines. PKC pathway activation in M-HCC cell lines was evident as pan phospho-PKC-substrate antibody gave strong reactivity along with a specific PKCα substrate such as PEA-15. Among different PKCs, only the expression of PKCα correlated with mesenchymal status (M-HCC cells). Other PKC family proteins were either uniformly expressed or not correlated with EMT status of HCC cell lines. b A dose-escalation study using two M-HCC cell lines revealed UCN-01 as more effective in inhibiting PKC activity as compared with Midostaurin. In both cell lines 20 nM UCN-01 inhibited PKC phosphorylation better than 2 μM of Midostaurin. c Transient knockdown of PKCα effectively inhibited the PKC activity in three M-HCC cells confirming that PKCα is responsible for the observed PKC activity in M-HCC cells. d Stable knockdown of PKCα with two different shRNAs inhibit viability of M-HCC cells as assessed by a colony formation assay. The decrease in colony number is significant (p < 0.01) in all cases. e PKC inhibition by 100 nM UCN-01 significantly reduced (SNU475) or completely inhibited (SNU387, SKHep1) the hepatosphere forming ability of M-HCC cell lines. PLC cells overexpressing ZEB1 (ZEB1-induced EMT) also showed a strong inhibition of hepatosphere formation ability upon UCN-01 treatment (bars on the right). The decrease in hepatosphere number was significant (p < 0.05) in all cases
