Regulation of autophagy gene expression and its implications in cancer

The autophagy paradox: A new hypothesis in neurodegenerative disorders

A recent study showed that while autophagy is usually tied to protein and organelle turnover, it can also play dual roles in neurodegenerative diseases. Traditionally, autophagy was seen as protective since it removes damaged proteins and organelles. but new data suggests autophagy can sometimes promote neuron death. and This review tackles autophagy's seemingly contradictory effects in neurodegeneration, or the "autophagy paradox. " It offers a framework for understanding autophagy in neurodegenerative research and the cellular processes involved. In short, our data uncovers a harmful autophagy role in certain situations, conflicting the view that it's always beneficial. We describe the distinct, disease-specific autophagy pathways functioning in various neurodegenerative diseases. Part two concerns potential therapeutic implications of manipulating autophagy and current strategies targeting the autophagic system, suggesting interesting areas for future research into tailored modulators. This could eventually enable activating or controlling specific autophagy pathways and aid in developing more effective treatments. Researchers believe more molecular-level research is needed so patient-tailored autophagy-modulating therapeutics can be developed given this dilemma. Moreover, research must translate faster into effective neurodegenerative disease treatment options. This article aims to provide a wholly new perspective on autophagy's classically described role in these severe diseases, challenging current dogma and opening new therapeutic avenue options.

Saikosaponins Targeting Programmed Cell Death as Anticancer Agents: Mechanisms and Future Perspectives

Saikosaponins (SS), which are major bioactive compounds in Radix Bupleuri, have long been used clinically for multicomponent, multitarget, and multipathway therapeutic strategies. Programmed cell death (PCD) induction is among the multiple mechanisms of SS and mediates the anticancer efficacy of this drug family. Although SS show promise for anticancer therapy, the available data to explain how SS mediate their key anticancer effects through PCD (apoptosis, autophagy, ferroptosis, and pyroptosis) remain limited and piecemeal. This review offers an extensive analysis of the key pathways and mechanisms involved in PCD and explores the importance of SS in cancer. We believe that high-quality clinical trials and a deeper understanding of the pharmacological targets involved in the signalling cascades that govern tumour initiation and progression are needed to facilitate the development of innovative SS-based treatments. Elucidating the specific anticancer pathways activated by SS and further clarifying how comprehensive therapies lead to cross-link among the different types of cell death will inspire the clinical translation of SS as cancer treatments.

The Chorioallantoic Membrane (CAM) Assay for the Analysis of Starvation-Induced Autophagy

During avian development, the chorioallantoic membrane (CAM) is generated around 4 days after fertilization following the fusion of the allantois and the chorion. The CAM develops rapidly over the next several days and gets heavily vascularized and therefore has been explored widely as a tool for the study of angiogenesis. Additionally, being immunodeficient, the CAM can be used for tumor growth of human origin and its metastasis. Of note, the CAM assay is minimally invasive for the chicken embryo and lacks innervation, which gives this in vivo model a low ethical burden. Here, we describe the protocol for the generation of microtumors from human colorectal cancer cell lines on the CAM, incubated in a nutrient-deficient medium for the activation of autophagy. We show that pre-inoculation markers of autophagy induced through nutrient deficiency are retained in the microtumors generated on the CAM.

[Calenduloside E inhibits hepatocellular carcinoma cell proliferation and migration by down-regulating GPX4 and SLC7A11 expression through the autophagy pathway]

OBJECTIVE

To investigate the molecular mechanism through which calenduloside E inhibits hepatocellular carcinoma (HCC) cell proliferation and migration.

METHODS

HCC cell lines HepG2 and Huh7 treated with calenduloside E were examined for changes in cell viability using CCK-8 assay and expressions of GPX4, SLC7A11, LC3, P62 and phosphorylation of Akt/mTOR using Western blotting. The effects LY294002 and Rapamycin (the inhibitor and activator of autophagy, respectively) on proliferation and migration of calenduloside E-treated HCC cells were evaluated using EdU and Transwell assays. The TCGA database was used to explore the expression levels of GPX4 and SLC7A11 in HCC and normal liver tissues and their correlation with the patients'survival outcomes. GPX4 and SLC7A11 expressions were also detected in HCC cells and normal hepatocytes using RT-qPCR and Western blotting.

RESULTS

Calenduloside E obviously inhibited the viability of HCC cells. GPX4 and SLC7A11 were highly expressed in HCC tissues and cell lines, and their expression levels were negatively correlated with the patients'survival. In HCC cell lines, calenduloside E significantly inhibited the expressions of GPX4 and SLC7A11 proteins, activated the Akt-mTOR pathway, and enhanced the expression of LC3 Ⅱ. The inhibitory effect of calenduloside E on GPX4 and SLC7A11 expressions was significantly enhanced by rapamycin but attenuated by LY294002. Inhibiting the autophagy pathway obviously diminished the inhibitory effect of calenduloside E on proliferation and migration of HCC cells, while activating this pathway produced the opposite effect.

CONCLUSION

Calenduside E inhibits the proliferation and migration of HCC cells by down-regulating GPX4 and SLC7A11 expression via the autophagy pathway.

Nutrient-dependent signaling pathways that control autophagy in yeast

Macroautophagy/autophagy is a highly conserved catabolic process vital for cellular stress responses and maintaining equilibrium within the cell. Malfunctioning autophagy has been implicated in the pathogenesis of various diseases, including certain neurodegenerative disorders, diabetes, metabolic diseases, and cancer. Cells face diverse metabolic challenges, such as limitations in nitrogen, carbon, and minerals such as phosphate and iron, necessitating the integration of complex metabolic information. Cells utilize a signal transduction network of sensors, transducers, and effectors to coordinate the execution of the autophagic response, concomitant with the severity of the nutrient-starvation condition. This review presents the current mechanistic understanding of how cells regulate the initiation of autophagy through various nutrient-dependent signaling pathways. Emphasizing findings from studies in yeast, we explore the emerging principles that underlie the nutrient-dependent regulation of autophagy, significantly shaping stress-induced autophagy responses under various metabolic stress conditions.

Unraveling the Janus-Faced Role of Autophagy in Hepatocellular Carcinoma: Implications for Therapeutic Interventions

This review aims to provide a comprehensive understanding of the molecular mechanisms underlying autophagy and mitophagy in hepatocellular carcinoma (HCC). Autophagy is an essential cellular process in maintaining cell homeostasis. Still, its dysregulation is associated with the development of liver diseases, including HCC, which is one of leading causes of cancer-related death worldwide. We focus on elucidating the dual role of autophagy in HCC, both in tumor initiation and progression, and highlighting the complex nature involved in the disease. In addition, we present a detailed analysis of a small subset of autophagy- and mitophagy-related molecules, revealing their specific functions during tumorigenesis and the progression of HCC cells. By understanding these mechanisms, we aim to provide valuable insights into potential therapeutic strategies to manipulate autophagy effectively. The goal is to improve the therapeutic response of liver cancer cells and overcome drug resistance, providing new avenues for improved treatment options for HCC patients. Overall, this review serves as a valuable resource for researchers and clinicians interested in the complex role of autophagy in HCC and its potential as a target for innovative therapies aimed to combat this devastating disease.