Involvement of PKCα activation in TF/VIIa/PAR2-induced proliferation, migration, and survival of colon cancer cell SW620

Our previous study has demonstrated that protease-activated receptor 2 (PAR2) activation mediated by tissue factor (TF)/VIIa complex triggers the ERK1/2/NF-kappa B signaling pathway, which further contributes to the proliferation and migration of colon cancer cell line SW620. However, the detailed mechanisms remain unclear. This study was to investigate whether protein kinase C alpha (PKC alpha) is involved in these events and the possible mechanism. The results revealed that PAR2-activating peptide or VIIa could induce time-dependent upregulation of PKC alpha phosphorylation in SW620 cells and PKC alpha translocation from the cytoplasm to the perinuclear region and nucleus. The activation of PKC alpha was sufficient to induce ERK1/2 and NF-kappa B phosphorylation. The VIIa effect was obviously blocked by both anti-TF and anti-PAR2 antibodies. The PKC alpha inhibitor, safingol, inhibited ERK1/2 phosphorylation and NF-kappa B activation that is induced by VIIa and abrogated the enhanced proliferation, migration, and survival of SW620 cells by VIIa treatment. Both safingol and PDTC (NF-kappa B inhibitor) could apparently rescue the effects of VIIa on expression of MMP-9, caspase-3, TF, and Bcl-2/bax in SW620 cells. Collectively, the data in this study suggest that TF/VIIa/PAR2-induced SW620 cell proliferation, migration, and survival are ascribed to the activation of PKC alpha, and these effects are achieved through PKC alpha downstream signaling pathways, ERK1/2 and NF-kappa B.