Antineoplastic Agents/pharmacology; Antineoplastic Agents/therapeutic use; Carcinoma, Hepatocellular/drug therapy; Carcinoma, Hepatocellular/metabolism; Cytoprotection/drug effects; Cytoprotection/genetics; Endoplasmic Reticulum Stress/drug effects; Liver Neoplasms/drug therapy; Liver Neoplasms/metabolism; Molecular Targeted Therapy; Niacinamide/analogs & derivatives; Phenylurea Compounds/pharmacology; Phenylurea Compounds/therapeutic use; Autophagy/drug effects; Autophagy/genetics; Carcinoma, Hepatocellular/etiology; Carcinoma, Hepatocellular/pathology; Drug Therapy, Combination; Endoplasmic Reticulum Stress/genetics; Humans; Keratins/metabolism; Liver Neoplasms/etiology; Liver Neoplasms/pathology; Niacinamide/pharmacology; Niacinamide/therapeutic use; Phosphorylation/drug effects; Prognosis; Proteasome Inhibitors/pharmacology; Proteasome Inhibitors/therapeutic use; Sorafenib; Unfolded Protein Response/drug effects