Quiescent fibroblasts are protected from proteasome inhibition-mediated toxicity.
Quiescent fibroblasts are protected from proteasome inhibition-mediated toxicity.
复制标题
DOI：
10.1091/mbc.e12-03-0192
复制
发表时间：
2012-09
影响因子：
3.3
通讯作者：
Coller HA
中科院分区：
文献类型：
--
作者：
Legesse-Miller A;Raitman I;Haley EM;Liao A;Sun LL;Wang DJ;Krishnan N;Lemons JM;Suh EJ;Johnson EL;Lund BA;Coller HA
蛋白酶体抑制是一种已批准的癌症疗法。静止的成纤维细胞比增殖的成纤维细胞对蛋白酶体抑制诱导的死亡具有更强的抵抗力。保护静止成纤维细胞的机制包括自噬/溶酶体途径、减少聚集体形成和活性氧解毒。蛋白酶体抑制被用作多种癌症的治疗策略。尽管蛋白酶体抑制可以在活跃增殖的细胞中诱导细胞凋亡，但在静止细胞中效果较差。在这项研究中，我们使用原代人成纤维细胞作为模型系统来探索细胞的增殖状态与蛋白酶体抑制介导的细胞死亡之间的联系。我们发现增殖和静止的成纤维细胞对蛋白酶体抑制剂 MG132 的反应截然不同。增殖细胞迅速凋亡，而静止细胞则保持活力。此外，MG132处理增殖的成纤维细胞导致超氧阴离子水平增加、泛素和p62/SQSTM1阳性蛋白聚集体的核旁积累以及细胞凋亡，而MG132处理的静止细胞表现出更少的核旁蛋白聚集、更少的细胞凋亡和更高水平的线粒体。 超氧化物歧化酶。在这两种细胞状态下，用 N-乙酰半胱氨酸减少活性氧可减少蛋白质聚集并减少细胞凋亡，表明蛋白质聚集促进细胞凋亡。相比之下，用 2-甲氧基雌二醇治疗增加细胞超氧化物水平或用巴弗洛霉素 A1 抑制自噬/溶酶体途径可使血清饥饿的静止细胞对 MG132 诱导的细胞凋亡敏感。因此，抗氧化防御和自噬/溶酶体途径可以保护血清饥饿的静止成纤维细胞免受蛋白酶体抑制诱导的细胞毒性。
Proteasome inhibition is an approved cancer therapy. Quiescent fibroblasts are much more resistant to proteasome inhibition–induced death than proliferating fibroblasts. Mechanisms that protect quiescent fibroblasts include autophagy/lysosomal pathways, diminished aggresome formation, and detoxification of reactive oxygen species. Proteasome inhibition is used as a treatment strategy for multiple types of cancers. Although proteasome inhibition can induce apoptotic cell death in actively proliferating cells, it is less effective in quiescent cells. In this study, we used primary human fibroblasts as a model system to explore the link between the proliferative state of a cell and proteasome inhibition–mediated cell death. We found that proliferating and quiescent fibroblasts have strikingly different responses to MG132, a proteasome inhibitor; proliferating cells rapidly apoptosed, whereas quiescent cells maintained viability. Moreover, MG132 treatment of proliferating fibroblasts led to increased superoxide anion levels, juxtanuclear accumulation of ubiquitin- and p62/SQSTM1-positive protein aggregates, and apoptotic cell death, whereas MG132-treated quiescent cells displayed fewer juxtanuclear protein aggregates, less apoptosis, and higher levels of mitochondrial superoxide dismutase. In both cell states, reducing reactive oxygen species with N-acetylcysteine lessened protein aggregation and decreased apoptosis, suggesting that protein aggregation promotes apoptosis. In contrast, increasing cellular superoxide levels with 2-methoxyestradiol treatment or inhibition of autophagy/lysosomal pathways with bafilomycin A1 sensitized serum-starved quiescent cells to MG132-induced apoptosis. Thus, antioxidant defenses and the autophagy/lysosomal pathway protect serum-starved quiescent fibroblasts from proteasome inhibition–induced cytotoxicity.