Mitochondrial Metabolic Signatures in Hepatocellular Carcinoma

Abstract

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death worldwide. HCC progression and metastasis are closely related to altered mitochondrial metabolism, including mitochondrial stress responses, metabolic reprogramming, and mitoribosomal defects. Mitochondrial oxidative phosphorylation (OXPHOS) defects and reactive oxygen species (ROS) production are attributed to mitochondrial dysfunction. In response to oxidative stress caused by increased ROS production, misfolded or unfolded proteins can accumulate in the mitochondrial matrix, leading to initiation of the mitochondrial unfolded protein response (UPR^mt). The mitokines FGF21 and GDF15 are upregulated during UPR^mt and their levels are positively correlated with liver cancer development, progression, and metastasis. In addition, mitoribosome biogenesis is important for the regulation of mitochondrial respiration, cell viability, and differentiation. Mitoribosomal defects cause OXPHOS impairment, mitochondrial dysfunction, and increased production of ROS, which are associated with HCC progression in mouse models and human HCC patients. In this paper, we focus on the role of mitochondrial metabolic signatures in the development and progression of HCC. Furthermore, we provide a comprehensive review of cell autonomous and cell non-autonomous mitochondrial stress responses during HCC progression and metastasis.

Keywords: glycolysis; hepatocellular carcinoma; mitochondria; mitochondrial unfolded protein response; mitoribosome.

Figure 1

The role of UPR^mt and mitokines in cancer progression. When mitochondria are under stress, OXPHOS perturbations, ROS production, and the level of unfolded proteins increase. Increased expression of proteases (ClpP & LONP1) and chaperone proteins (HSP60) during UPR^mt promotes mitokine (FGF21 & GDF15) expression, which affects tumor development and progression. LONP1, Lon protease 1.