Autophagic protein ULK1 regulates FOXM1 signalling in human hepatoma cells

ULK1 inhibition attenuates telomerase activity in hepatic cells

Autophagy and telomere maintenance are two cellular survival processes that show a strong correlation during human ageing and cancer growth, however, their causal relationship remains unclear. In this study, using an unbiased transcriptomics approach, we uncover a novel role of autophagy genes in regulating telomere extension and maintenance pathways. Concomitantly, the pharmacological inhibition of ULK1 (Unc-51 like autophagy activating kinase 1) attenuated human telomerase reverse transcriptase (hTERT) gene expression and telomerase activity in HepG2 cells. Furthermore, the suppression of telomerase activity upon ULK1 inhibition was associated with telomere shortening and onset of cellular senescence in HepG2 cells. These results, thus, demonstrate a direct role of autophagy in maintaining cellular longevity via regulation of telomerase activity, which may have implications in the pathophysiology of ageing and cancers.

The pathogenesis of liver cancer and the therapeutic potential of bioactive substances

Liver cancer is the third most common cause of cancer-related deaths in the world and has become an urgent problem for global public health. Bioactive substances are widely used for the treatment of liver cancer due to their widespread availability and reduced side effects. This review summarizes the main pathogenic factors involved in the development of liver cancer, including metabolic fatty liver disease, viral infection, and alcoholic cirrhosis, and focuses on the mechanism of action of bioactive components such as polysaccharides, alkaloids, phenols, peptides, and active bacteria/fungi. In addition, we also summarize transformation methods, combined therapy and modification of bioactive substances to improve the treatment efficiency against liver cancer, highlighting new ideas in this field.

ULK1 Signaling in the Liver: Autophagy Dependent and Independent Actions

Liver is the primary organ for energy metabolism and detoxification in the human body. Not surprisingly, a derangement in liver function leads to several metabolic diseases. Autophagy is a cellular process, which primarily deals with providing molecules for energy production, and maintains cellular health. Autophagy in the liver has been implicated in several hepatic metabolic processes, such as, lipolysis, glycogenolysis, and gluconeogenesis. Autophagy also provides protection against drugs and pathogens. Deregulation of autophagy is associated with the development of non-alcoholic fatty liver disease (NAFLD) acute-liver injury, and cancer. The process of autophagy is synchronized by the action of autophagy family genes or autophagy (Atg) genes that perform key functions at different steps. The uncoordinated-51-like kinases 1 (ULK1) is a proximal kinase member of the Atg family that plays a crucial role in autophagy. Interestingly, ULK1 actions on hepatic cells may also involve some autophagy-independent signaling. In this review, we provide a comprehensive update of ULK1 mediated hepatic action involving lipotoxicity, acute liver injury, cholesterol synthesis, and hepatocellular carcinoma, including both its autophagic and non-autophagic functions.