Relationship between endoplasmic reticulum stress protein kinase R-like endoplasmic reticulum kinase/eukaryotic initiation factor 2a/activating transcription factor 6 pathway and proliferation and migration of rat hepatoma cells

Abstract

Objective To investigate the relationship between endoplasmic reticulum stress protein kinase R-like endoplasmic reticulum kinase (PERK)/eukaryotic initiation factor 2a (eIF-2α)/activating transcription factor 6 (ATF6) pathway and proliferation and migration of rat hepatoma cells. Methods Rat liver cancer model was established by intermittent administration of diethylnitrosamine (DEN). Morphological changes of rat liver were observed by hematoxylin-eosin staining (HE) staining. The expression of PERK and eIF-2α protein in rat hepatocarcinoma tissues was detected by immunohistochemistry. The endoplasmic reticulum stress cell model was constructed by inducing normal liver cell LO2 and highly differentiated hepatoma cell line CBRH-7919 with absolute ethanol. Cell counting kit-8 (CCK-8) method was used to detect the proliferation of cells; the migration and invasion ability of cells were detected by scratch test; the PERK, eIF-2α, ATF6, and B lymphoma-2 were detected by Western blotting. Expression of bcl-2 and cysteine-containing aspartate proteolytic enzyme-3 (Caspase-3) protein, and statistical calculation. Results Liver cells in liver cancer were found to be irregularly arranged. Hepatocytes showed severe abnormalities, nuclear membrane depression, deep nuclear staining, and abnormal nuclear morphology of liver cells. After ethanol-induced LO2 and CBRH-7919 cells undergo endoplasmic reticulum stress, the cell migration ability of LO2 and CBRH-7919 cells was significantly decreased (tLO2 cells=8.910, P<0.01; tCBRH-7919 cells=30.010, P<0.01). The survival rates of LO2 and CBRH-7919 cells were significantly lower, and the difference was statistically significant (tLO2 cells=11.840, P<0.01; tCBRH-7919 cells=19.080, P<0.01). The expressions of PERK, eIF-2α, ATF6 and Caspase-3 in the liver cancer tissues of the experimental group were significantly increased, and the expression of bcl-2 protein was significantly decreased (tPERK=8.070, P<0.01; teIF-2α=11.790, P<0.01; tATF6= 7.750, P<0.01; tbcl-2=8.670, P<0.01; tCaspase-3=7.720, P<0.01). After ethanol-induced endoplasmic reticulum stress in LO2 cells, the expression levels of PERK, eIF-2α, ATF6, bcl-2 and Caspase-3 in LO2 cells were significantly increased, and bcl-2 protein expression was significantly decreased (tPERK=12.910, P<0.01; teIF-2α= 15.810, P<0.01; tATF6=7.690, P<0.01; tbcl-2=23.260, P<0.01; tCaspase-3=22.280, P<0.01). After the endoplasmic reticulum stress induced by absolute ethanol in CBRH-7919 cells, the expression of PERK, eIF-2α, ATF6, bcl-2 and Caspase-3 protein in CBRH-7919 cells was significantly increased, and the expression of bcl-2 protein was significantly decreased (tPERK= 9.560, P<0.01; teIF-2α= 12.400, P<0.01; tATF6=6.880, P<0.01; tbcl-2=13.840, P<0.01; tCaspase-3=9.950, P<0.01). Conclusion Activation of the PERK/eIF-2α/ATF4 pathway in endoplasmic reticulum stress significantly inhibits the proliferation and migration of rat hepatoma cells. Key words: Liver cancer; Endoplasmic reticulum stress; Protein kinase R-like endoplasmic reticulum kinase; Eukaryotic initiation factor 2α; Transcriptional activator-6