LC3A-mediated autophagy elicits PERK-eIF2α-ATF4 axis activation and mitochondrial dysfunction: Exposing vulnerability in aggresome-positive cancer cells.
J Biol Chem
; 300(6): 107398, 2024 Jun.
Article
em En
| MEDLINE
| ID: mdl-38777145
ABSTRACT
The unfolded protein response pathways (UPR), autophagy, and compartmentalization of misfolded proteins into inclusion bodies are critical components of the protein quality control network. Among inclusion bodies, aggresomes are particularly intriguing due to their association with cellular survival, drug resistance, and aggresive cancer behavior. Aggresomes are molecular condensates formed when collapsed vimentin cages encircle misfolded proteins before final removal by autophagy. Yet significant gaps persist in the mechanisms governing aggresome formation and elimination in cancer cells. Understanding these mechanisms is crucial, especially considering the involvement of LC3A, a member of the MAP1LC3 family, which plays a unique role in autophagy regulation and has been reported to be epigenetically silenced in many cancers. Herein, we utilized the tetracycline-inducible expression of LC3A to investigate its role in choroid plexus carcinoma cells, which inherently exhibit the presence of aggresomes. Live cell imaging was employed to demonstrate the effect of LC3A expression on aggresome-positive cells, while SILAC-based proteomics identified LC3A-induced protein and pathway alterations. Our findings demonstrated that extended expression of LC3A is associated with cellular senescence. However, the obstruction of lysosomal degradation in this context has a deleterious effect on cellular viability. In response to LC3A-induced autophagy, we observed significant alterations in mitochondrial morphology, reflected by mitochondrial dysfunction and increased ROS production. Furthermore, LC3A expression elicited the activation of the PERK-eIF2α-ATF4 axis of the UPR, underscoring a significant change in the protein quality control network. In conclusion, our results elucidate that LC3A-mediated autophagy alters the protein quality control network, exposing a vulnerability in aggresome-positive cancer cells.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Autofagia
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Fator de Iniciação 2 em Eucariotos
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EIF-2 Quinase
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Fator 4 Ativador da Transcrição
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Proteínas Associadas aos Microtúbulos
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Mitocôndrias
Limite:
Humans
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Egito