title: [Sorafenib and octreotide combination therapy can inhibit proliferation of and induce apoptosis in human hepatoma cells].
abstract: To investigate the effects of sorafenib and octreotide combination treatment on cellular proliferation and explore the underlying molecular mechanisms by using an in vitro cell culture system with the human hepatoma cell line, HepG2. HepG2 cells were treated with different concentrations of sorafenib and octreotide alone or in combination. Untreated HepG2 cells were used as controls. Treatment-induced cytotoxicity was determined with the cell counting kit-8 by Sigma-Aldrich, and rate of apoptosis was detected by flow cytometry. Fluorescent microscopy was used to observe rates of cell growth under the various treatments. Treatment-induced changes in protein expressions were detected by enzyme-linked immunosorbent assay (for vascular endothelial growth factor (VEGF)) and Western blotting (for the Mcl-1 apoptosis mediator and the ERK1/2 and PERK1/2 kinases). Sorafenib and octreotide, used alone or in combination, inhibited proliferation and induced apoptosis in HepG2 cells. Combination treatment was more effective than either mono-treatment (F = 200.398, P less than 0.05). Fluorescent microscopy showed that combination treatment stimulated phosphatidylserine, the marker of early apoptosis, better than either mono-treatment. VEGF expression in cultures exposed to combination treatment was also significantly lower than in mono-treatment or untreated control cultures (F = 1019.725, P less than 0.05). Western blotting showed that octreotide mono-treatment had no effect on Mcl-1 expression (vs. control group; P more than 0.05) and that combination treatment significantly lowered Mcl-1 expression (vs. mono-treatment and control groups; P less than 0.05). None of the treatments affected ERK1/2 expression (all, P more than 0.05), while all treatments significantly lowered PERK1/2 expression (vs. control group; F = 2.401, P less than 0.05) and the combination treatment lowered PERK1/2 significantly more than either mono-treatment (P less than 0.05). Sorafenib and octreotide can inhibit proliferation and induce apoptosis in the human hepatoma cell line, HepG2. Combination treatment is significantly more efficacious (P less than 0.05) and produced synergistic effects. The mechanism underlying this phenomenon may depend on synergistic inhibition of VEGF, the  anti-apoptotic protein Mcl-1, and the proliferation-inducing PERK1/2.
authors.affiliation: Department of Gastroenterology, the Second Affiliated Hospital, Chongqing Medical University, Chongqing, China.
authors.forename: Zhao-Dong
authors.initials: ZD
authors.lastname: Li
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Liao
authors.forename: Guo-Qing
authors.initials: GQ
authors.lastname: Zuo
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001557:Benzenesulfonates / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects*; D056945:Hep G2 Cells / Q000187:drug effects; D006801:Humans; D009536:Niacinamide / Q000031:analogs & derivatives; D015282:Octreotide / Q000494:pharmacology*; D010671:Phenylurea Compounds; D011725:Pyridines / Q000494:pharmacology*; D000077157:Sorafenib
chemical_list: D001557:Benzenesulfonates; D010671:Phenylurea Compounds; D011725:Pyridines; D009536:Niacinamide; D000077157:Sorafenib; D015282:Octreotide