ROS-mediated lysosomal membrane permeabilization and autophagy inhibition regulate bleomycin-induced cellular senescence
Creators: name: Qi, Zhangyang
name: Yang, Weiqi
name: Xue, Baibing
name: Chen, Tingjun
name: Lu, Xianjie
name: Zhang, Rong
name: Li, Zhichao
name: Zhao, Xiaoqing
name: Zhang, Yang
name: Han, Fabin
name: Kong, Xiaohong
name: Liu, Ruikang
name: Yao, Xue
name: Jia, Rui
name: Feng, Shiqing
Publisher: name: Taylor & Francis
Year: 2024
Subjects: subject: Biochemistry
subject: Medicine
subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Physiology
subject: Pharmacology
subject: Immunology
subject: FOS: Clinical medicine
subject: Developmental Biology
subject: Cancer
subject: Infectious Diseases
subject: FOS: Health sciences

description: Bleomycin exhibits effective chemotherapeutic activity against multiple types of tumors, and also induces various side effects, such as pulmonary fibrosis and neuronal defects, which limit the clinical application of this drug. Macroautophagy/autophagy has been recently reported to be involved in the functions of bleomycin, and yet the mechanisms of their crosstalk remain insufficiently understood. Here, we demonstrated that reactive oxygen species (ROS) produced during bleomycin activation hampered autophagy flux by inducing lysosomal membrane permeabilization (LMP) and obstructing lysosomal degradation. Exhaustion of ROS with N-acetylcysteine relieved LMP and autophagy defects. Notably, we observed that LMP and autophagy blockage preceded the emergence of cellular senescence during bleomycin treatment. In addition, promoting or inhibiting autophagy-lysosome degradation alleviated or exacerbated the phenotypes of senescence, respectively. This suggests the alternation of autophagy activity is more a regulatory mechanism than a consequence of bleomycin-induced cellular senescence. Taken together, we reveal a specific role of bleomycin-induced ROS in mediating defects of autophagic degradation and further regulating cellular senescence <i>in vitro</i> and <i>in vivo</i>. Our findings, conversely, indicate the autophagy-lysosome degradation pathway as a target for modulating the functions of bleomycin. These provide a new perspective for optimizing bleomycin as a clinically applicable chemotherapeutics devoid of severe side-effects. <b>Abbreviations</b>: AT2 cells: type II alveolar epithelial cells; ATG7: autophagy related 7; bEnd.3: mouse brain microvascular endothelial cells; BNIP3L: BCL2/adenovirus E1B interacting protein 3-like; CCL2: C-C motif chemokine ligand 2; CDKN1A: cyclin dependent kinase inhibitor 1A; CDKN2A: cyclin dependent kinase inhibitor 2A; FTH1: ferritin heavy polypeptide 1; γ-H2AX: phosphorylated H2A.X variant histone; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HUVEC: human umbilical vein endothelial cells; HT22: hippocampal neuronal cell lines; Il: interleukin; LAMP: lysosomal-associated membrane protein; LMP: lysosome membrane permeabilization; MTORC1: mechanistic target of rapamycin kinase complex 1; NAC: N-acetylcysteine; NCOA4: nuclear receptor coactivator 4; PI3K: phosphoinositide 3-kinase; ROS: reactive oxygen species; RPS6KB/S6K: ribosomal protein S6 kinase; SA-GLB1/β-gal: senescence-associated galactosidase, beta 1; SAHF: senescence-associated heterochromatic foci; SASP: senescence-associated secretory phenotype; SEC62: SEC62 homolog, preprotein translocation; SEP: superecliptic pHluorin; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB