Lying FGFR2c-mediated EMT inside the context of human keratinocytes [8,21]. The involvement of PKC was investigated taking benefit of your use of distinct shRNA approaches, which showed that PKC depletion strongly impairs the boost of EMT signature, too as the morphological modifications triggered by FGF2 in Mefenpyr-diethyl custom synthesis PANC-1 cells. Interestingly, only in these cells PKC phosphorylation/SF1126 Biological Activity activation is appreciable, suggesting that PKC activation could possibly be dependent on FGFR2c expression price. Considering the fact that PKCs are thought of “RAS-independent” signaling substrates activated by various membrane receptors, including FGFRs [6], the identification of certainly one of PKC family members members as a pivotal signaling effector in the establishment of EMT phenotype (and possibly a larger aggressive behavior) could represent a basic advance towards new therapeutic strategies aimed to bypass the “undruggable” targetCancers 2021, 13,17 ofRAS. Interestingly, we also identified that PKC silencing abolished the potential of FGF2 to repress autophagy, another essential approach contributing to PDAC improvement and progression [2,14,15]. Autophagy and EMT in cancer are linked within a complex crosstalk [13], which we’ve got lately proposed to be regulated by FGFR2c and, to some extent, by its downstream PKC-mediated signaling, no less than throughout the early methods of human epidermal carcinogenesis [8,21,30]. In line with our earlier information, here we highlighted a damaging effect of PKC downstream FGFR2c on autophagy at the least in the PANC-1 cell model, which highly expresses the receptor. Even so, though autophagy is possibly repressed throughout the early phases of tumorigenesis, in advanced and aggressive cancers, like those from which PANC-1 and Mia PaCa-2 cell lines are derived, this approach is enhanced, and it is extensively described as an oncogenic event sustaining cell survival and metabolism [15]. Similarly to what has been already proposed in PDAC for MEK/ERK signaling in PDAC [14], our findings is usually explained taking into consideration that a unfavorable regulation of autophagy (including that exerted by FGR2c and by its PKC downstream signaling) basically results in an oncogenic effect, because it can counteract tumor cell dependence on autophagy for survival. In this perspective, the specific repression of PKC not only induces a reversion of EMT, but also increases autophagy, enhancing tumor cell dependence on this survival technique and consequently their susceptibility to autophagic inhibitors. Moreover, investigating in detail the molecular mechanisms underlying the inhibitory impact exerted by PKC on autophagy, we located that the depletion of PKC repressed the phosphorylation/activation on the autophagic inhibitor MTOR, visible only in PANC-1 cells in response to FGF2. The se benefits indicated that, as not too long ago proposed in breast cancer [18], PKC could repress autophagy activating the canonical MTOR autophagy-related pathway also in PDAC. Moreover, PKC depletion strongly repressed ERK1/2 phosphorylation in both PDAC cell lines, even if MiaPaCa-2 cells appear to sustain a residual ERK1/2 phosphorylation, suggesting that the dependence of ERK1/2 signaling on PKC activation is consequent on FGFR2c expression levels. Also, PKC depletion appeared ineffective around the phosphorylation of AKT, that is the canonical activator of MTOR, suggesting that, as previously proposed for cardiomyocytes [25], PKC could bypass AKT and directly activate MTOR via ERK1/2. Thinking about that ERK1/2 is also a well-known pathway regulating EMT.
