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Apoptosis : An International Journal on... Dec 2018Autophagy is an evolutionarily conserved catabolic process that plays an essential role in maintaining cellular homeostasis by degrading unneeded cell components. When... (Review)
Review
Autophagy is an evolutionarily conserved catabolic process that plays an essential role in maintaining cellular homeostasis by degrading unneeded cell components. When exposed to hostile environments, such as hypoxia or nutrient starvation, cells hyperactivate autophagy in an effort to maintain their longevity. In densely packed solid tumors, such as glioblastoma, autophagy has been found to run rampant due to a lack of oxygen and nutrients. In recent years, targeting autophagy as a way to strengthen current glioblastoma treatment has shown promising results. However, that protective autophagy inhibition or autophagy overactivation is more beneficial, is still being debated. Protective autophagy inhibition would lower a cell's previously activated defense mechanism, thereby increasing its sensitivity to treatment. Autophagy overactivation would cause cell death through lysosomal overactivation, thus introducing another cell death pathway in addition to apoptosis. Both methods have been proven effective in the treatment of solid tumors. This systematic review article highlights scenarios where both autophagy inhibition and activation have proven effective in combating chemoresistance and radioresistance in glioblastoma, and how autophagy may be best utilized for glioblastoma therapy in clinical settings.
Topics: Antineoplastic Agents; Autophagosomes; Autophagy; Brain Neoplasms; Cell Death; Drug Resistance, Neoplasm; Glioblastoma; Humans; Radiation-Sensitizing Agents; Temozolomide
PubMed: 30171377
DOI: 10.1007/s10495-018-1480-9 -
Cells Sep 2020Autophagy, a conserved process in which cells break down and destroy old, damaged, or abnormal proteins and other substances in the cytoplasm through lysosomal...
Autophagy, a conserved process in which cells break down and destroy old, damaged, or abnormal proteins and other substances in the cytoplasm through lysosomal degradation, occurs via autophagosome formation and aids in the maintenance of intracellular homeostasis. Autophagy is closely associated with hepatitis B virus (HBV) replication and assembly. Currently, HBV infection is still one of the most serious public health issues worldwide. The unavailability of satisfactory therapeutic strategies for chronic HBV infection indicates an urgent need to elucidate the mechanisms underlying the pathogenesis of HBV infection. Increasing evidence has shown that HBV not only possesses the ability to induce incomplete autophagy but also evades autophagic degradation, indicating that HBV utilizes or hijacks the autophagy machinery for its own replication. Therefore, autophagy might be a crucial target pathway for controlling HBV infection. The definite molecular mechanisms underlying the association between cellular autophagy and HBV replication require further clarification. In this review, we have summarized and discussed the latest findings on the interplay between autophagy and HBV replication.
Topics: Animals; Antiviral Agents; Apoptosis; Autophagosomes; Autophagy; Hepatitis B virus; Hepatitis B, Chronic; Host Microbial Interactions; Humans; Lysosomes; Mice; Trans-Activators; Viral Regulatory and Accessory Proteins; Virion; Virus Replication
PubMed: 32942717
DOI: 10.3390/cells9092101 -
Evidence-based Complementary and... 2020At present, the relationship between autophagosomes and the prognosis of various cancers has become a subject of active investigation. A series of studies have... (Review)
Review
OBJECTIVE
At present, the relationship between autophagosomes and the prognosis of various cancers has become a subject of active investigation. A series of studies have demonstrated the correlation between autophagy microtubule-associated protein light chain 3 (LC-3), Beclin-1, and colorectal cancer (CRC). Since autophagy has dual regulatory roles in tumors, the results of this correlation are also uncertain. Hence, we summarized the relationship between Beclin-1, LC-3, and CRC using systematic reviews and meta-analysis to clarify their prognostic significance in it.
METHODS
PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched online up to April 1, 2019. The quality of the involving studies was assessed against the Newcastle-Ottawa Scale (NOS). Pooled hazard ratio (HR) and 95% confidence interval (CI) in a fixed or random effects model were used to assess the strength of correlation between Beclin-1, LC-3, and CRC.
RESULTS
A total of 9 articles were collected, involving 2,297 patients. Most literatures scored more than 6 points, suggesting that the quality of our including research was acceptable. Our finding suggested that the expression of Beclin-1 was not associated with overall survival (HR = 0.68, 95% CI (0.31-1.52), =0.351). Nonetheless, LC-3 expression exerted significant impact on OS (HR = 0.51, 95% CI (0.35-0.74), < 0.05). Subgroup analysis exhibited that Beclin-1 expression was associated with OS at TNM stage III (HR = 0.04, 95% CI = 0.02-0.08, < 0.05), surgical treatment (HR = 1.53, 95% CI (1.15-2.02), =0.003), and comprehensive treatment (HR = 0.27 95% CI (0.08-0.92), =0.036), respectively. Similarly, the results showed the increased LC-3 expression in CRC was related to OS in multivariate analyses (HR = 0.44, 95% CI (0.34-0.57), < 0.05), stages (HR = 0.51, 95% CI (0.35-0.74), < 0.05), and comprehensive treatment (HR = 0.44, 95% CI (0.34-0.57), < 0.05).
CONCLUSIONS
Autophagy-related proteins of LC-3 might be an important marker of CRC progression. However, since the number of the original studies was limited, more well-designed, large-scale, high-quality studies are warranted to provide more convincing and reliable information.
PubMed: 32280357
DOI: 10.1155/2020/8475840 -
Frontiers in Molecular Neuroscience 2021A typical neuron consists of a soma, a single axon with numerous nerve terminals, and multiple dendritic trunks with numerous branches. Each of the 100 billion neurons...
A typical neuron consists of a soma, a single axon with numerous nerve terminals, and multiple dendritic trunks with numerous branches. Each of the 100 billion neurons in the brain has on average 7,000 synaptic connections to other neurons. The neuronal endolysosomal compartments for the degradation of axonal and dendritic waste are located in the soma region. That means that all autophagosomal and endosomal cargos from 7,000 synaptic connections must be transported to the soma region for degradation. For that reason, neuronal endolysosomal degradation is an extraordinarily demanding and dynamic event, and thus is highly susceptible to many pathological conditions. Dysfunction in the endolysosomal trafficking pathways occurs in virtually all neurodegenerative diseases. Most lysosomal storage disorders (LSDs) with defects in the endolysosomal system preferentially affect the central nervous system (CNS). Recently, significant progress has been made in understanding the role that the endolysosomal trafficking pathways play after brain ischemia. Brain ischemia damages the membrane fusion machinery co-operated by N-ethylmaleimide sensitive factor (NSF), soluble NSF attachment protein (SNAP), and soluble NSF attachment protein receptors (SNAREs), thus interrupting the membrane-to-membrane fusion between the late endosome and terminal lysosome. This interruption obstructs all incoming traffic. Consequently, both the size and number of endolysosomal structures, autophagosomes, early endosomes, and intra-neuronal protein aggregates are increased extensively in post-ischemic neurons. This cascade of events eventually damages the endolysosomal structures to release hydrolases leading to ischemic brain injury. Gene knockout and selective inhibition of key endolysosomal cathepsins protects the brain from ischemic injury. This review aims to provide an update of the current knowledge, future research directions, and the clinical implications regarding the critical role of the neuronal endolysosomal trafficking pathways in ischemic brain injury.
PubMed: 34650402
DOI: 10.3389/fnmol.2021.719100