The multikinase inhibitor Sorafenib enhances glycolysis and synergizes with glycolysis blockade for cancer cell killing

Abstract

Although the only effective drug against primary hepatocarcinoma, the multikinase inhibitor Sorafenib (SFB) usually fails to eradicate liver cancer. Since SFB targets mitochondria, cell metabolic reprogramming may underlie intrinsic tumor resistance. To characterize cancer cell metabolic response to SFB, we measured oxygen consumption, generation of reactive oxygen species (ROS) and ATP content in rat LCSC (Liver Cancer Stem Cells) -2 cells exposed to the drug. Genome wide analysis of gene expression was performed by Affymetrix technology. SFB cytotoxicity was evaluated by multiple assays in the presence or absence of metabolic inhibitors, or in cells genetically depleted of mitochondria. We found that low concentrations (2.5–5 μM) of SFB had a relatively modest effect on LCSC-2 or 293 T cell growth, but damaged mitochondria and increased intracellular ROS. Gene expression profiling of SFB-treated cells was consistent with a shift toward aerobic glycolysis and, accordingly, SFB cytotoxicity was dramatically increased by glucose withdrawal or the glycolytic inhibitor 2-DG. Under metabolic stress, activation of the AMP dependent Protein Kinase (AMPK), but not ROS blockade, protected cells from death. We conclude that mitochondrial damage and ROS drive cell killing by SFB, while glycolytic cell reprogramming may represent a resistance strategy potentially targetable by combination therapies.

Synergistic effects of ascorbate and sorafenib in hepatocellular carcinoma: New insights into ascorbate cytotoxicity

“…This finding indicates that sorafenib treatment suppresses mitochondrial energy conservation. Sorafenib has been previously reported to inhibit mitochondrial Complex I activity (61, 62). Importantly, mitochondrial depolarization by sorafenib treatment in the absence of ascorbate did not elicit the calcium increase and cell permeabilization, indicating that ascorbate is required for the dramatic rise in [Ca 2+ cyto ] and the effect of sorafenib treatment and the consequent mitochondrial depolarization is to sensitize the cells to the specific actions of ascorbate (Fig.…”

Multiple Roles of Autophagy in the Sorafenib Resistance of Hepatocellular Carcinoma

“…AMPK can initiate autophagy through inactivation of mTORC1 or by phosphorylation of ULK1 [70, 71]. It is possible that sorafenib activates AMPK by inducing cellular ATP reduction and a corresponding increase in the AMP/ATP ratio [72, 73]. Curiously, there are differences in sorafenib-dependent modulation of AMPK in HCC cell lines, where AMPK and consequently autophagy were activated in Huh7, but not in Hep3B cells.…”

“…Therefore, different autophagy responsiveness to sorafenib might be linked to generation of sorafenib resistance. Nevertheless, the AMPK pathway may be not involved in sorafenib-induced autophagy, since LC3-II was still upregulated significantly when AMPK was inhibited in HCC cells cultured with sorafenib [73, 74]. …”

Sorafenib and 2-Deoxyglucose Synergistically Inhibit Proliferation of Both Sorafenib-Sensitive and -Resistant HCC Cells by Inhibiting ATP Production

“…One study demonstrated that exposure of rat hepatocolangiocarcinoma cells to sorafenib induces increased rates of glycolysis 10 . Another study demonstrated that increased glycolytic utilization has a strong correlation with sorafenib resistance across several HCC cell lines 9 .…”

“…A handful of studies have demonstrated that a variety of mechanisms are involved in maintaining sorafenib resistance, which include CD44 overexpression 1 , activation of PI3K/AKT signaling 7 and increased MAPK14 activity 8 . Another group of studies has linked sorafenib sensitivity to cellular metabolism and glycolysis 9,10 . These studies are interesting because sorafenib therapy has been shown to inhibit oxidative phosphorylation and enhance glycolysis in a subset of HCC cell lines 2 .…”