Macroautophagy/autophagy degrades proteins and organelles to generate macromolecular building blocks. As such, some cancer cells are particularly dependent on autophagy. In a previous paper, we found that even highly autophagy-dependent cancer cells can adapt to circumvent autophagy inhibition. However, it remains unclear if autophagy-dependent cancer cells could survive the complete elimination of autophagosome formation. We extended our previous findings to show that knockout (KO) of both the upstream autophagy regulator RB1CC1/FIP200 and the downstream regulator and mediator of LC3 conjugation, ATG7, strongly inhibits growth in highly autophagy-dependent cells within one week of editing. However, rare clones survived the loss of ATG7 or RB1CC1 and maintained growth even under autophagy-inducing conditions. Autophagy-dependent cells circumvent the complete loss of autophagy that is mediated by RB1CC1 KO, similar to the loss of ATG7, by upregulating NFE2L2/NRF2 signaling. These results indicate that cancer cell lines could adapt to the complete loss of autophagy by changing their biology to adopt alternative ways of dealing with autophagy-mediated cellular functions.Abbreviations: CGS: CRISPR growth score; CQ: chloroquine; CRISPR: clustered regularly interspaced short palindromic repeats; EBSS: Earl's balanced salt solution; EEF2: eukaryotic translation elongation factor 2; FOXO3/FOXO3a: forkhead box O3; GFP: green fluorescent protein; KEAP1: kelch Like ECH associated protein 1; KO: knockout; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MEFs: mouse embryonic fibroblasts; NFE2L2/NRF2: nuclear factor, erythroid 2 like 2; NLS: nuclear localization signal; PCNA: proliferating cell nuclear antigen; PE: phosphatidylethanolamine; POLR2A: RNA polymerase II subunit A; PTEN: phosphatase and tensin homolog; ROS: reactive oxygen species; SNARE: soluble NSF attachment protein receptor; SQSTM1: sequestosome 1; STX17: syntaxin 17; TBHP: tert-butyl hydroperoxide; ULK1: unc-51 like autophagy activating kinase 1; ULK2: unc-51 like autophagy activating kinase 2; WT: wild type.

中文翻译：

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自噬依赖性癌细胞可通过类似机制规避上游调节子RB1CC1 / FIP200的丢失和LC3偶联的丢失。

巨自噬/自噬降解蛋白质和细胞器以产生大分子构件。因此，某些癌细胞特别依赖自噬。在以前的论文中，我们发现即使高度自噬的癌细胞也可以适应自噬抑制。然而，尚不清楚自噬依赖性癌细胞是否能在自噬体形成的完全消除中存活下来。我们扩展了我们以前的发现，以显示上游自噬调节剂RB1CC1 / FIP200和下游调节剂及LC3偶联介导物ATG7的敲除（KO）在编辑后一周内强烈抑制高度自噬依赖性细胞的生长。然而，即使在自噬诱导条件下，稀有克隆也能幸免于ATG7或RB1CC1的丢失并保持生长。自噬依赖性细胞通过上调NFE2L2 / NRF2信号传导，避免了RB1CC1 KO介导的自噬的完全丧失，类似于ATG7的丧失。这些结果表明癌细胞系可以通过改变其生物学特性以采取替代方法来处理自噬介导的细胞功能来适应自噬的完全丧失。CQ：氯喹；CRISPR：成簇规则间隔的短回文重复序列；EBSS：伯爵的平衡盐溶液；EEF2：真核翻译延伸因子2；FOXO3 / FOXO3a：前叉箱O3；GFP：绿色荧光蛋白；KEAP1：海带样ECH相关蛋白1；KO：淘汰赛；MAP1LC3B / LC3B：微管相关蛋白1轻链3 beta；MEF：小鼠胚胎成纤维细胞；NFE2L2 / NRF2：核因子，类红细胞2，2；NLS：核定位信号 PCNA：增殖细胞核抗原；PE：磷脂酰乙醇胺；POLR2A：RNA聚合酶II亚基A；PTEN：磷酸酶和张力蛋白同源物；ROS：活性氧；SNARE：可溶性NSF附着蛋白受体；SQSTM1：螯合体1；STX17：syntaxin 17；TBHP：氢过氧化叔丁基；ULK1：unc-51样自噬激活激酶1；ULK2：unc-51样自噬激活激酶2；WT：野生型。unc-51样自噬激活激酶2；WT：野生型。unc-51样自噬激活激酶2；WT：野生型。