Anti-cancer therapies can induce cellular senescence, which is highly stable, or drug-tolerant persistence, which is efficiently reversed upon therapy termination. While approaches to target senescent cells have been extensively studied, further understanding of the processes regulating persistence is needed to develop treatment strategies to suppress persister cell survival. Here, we used mTOR/PI3K inhibition to develop and characterize a model of persistence-associated arrest in human cancer cells of various origins. Persister and senescent cancer cells shared an expanded lysosomal compartment and hypersensitivity to BCL-XL inhibition. However, persister cells lacked other features of senescence, such as loss of lamin B1, senescence-associated β-galactosidase activity, upregulation of MHC-I, and an inflammatory and secretory phenotype (SASP). Genome-wide CRISPR/Cas9 screening for genes required for the survival of persister cells revealed that they are hypersensitive to the inhibition of one-carbon (1C) metabolism, which was validated by the pharmacological inhibition of SHMT, a key enzyme that feeds methyl groups from serine into 1C metabolism. Connecting 1C metabolism with the epigenetic regulation of transcription, the repressive heterochromatic mark H4K20me3 was enriched at the promoters of SASP and interferon response genes in persister cells, while it was absent in proliferative or senescent cells. Moreover, persister cells overexpressed the H4K20 methyltransferases KMT5B/C, and their downregulation unleashed inflammatory programs and compromised the survival of persister cells. In summary, this study defined distinctive features of persister cancer cells, identified actionable vulnerabilities, and provided mechanistic insight into their low inflammatory activity.

中文翻译：

---

H4K20me3 介导的炎症基因抑制是持续性癌细胞的一种特征性和靶向性脆弱性


抗癌疗法可以诱导细胞衰老，这是高度稳定的，或者是耐药的持久性，在治疗终止时可以有效逆转。虽然靶向衰老细胞的方法已被广泛研究，但需要进一步了解调节持久性的过程，以制定抑制持久性细胞存活的治疗策略。在这里，我们使用 mTOR/PI3K 抑制来开发和表征各种来源的人类癌细胞中持续相关停滞的模型。持续癌细胞和衰老癌细胞共享一个扩大的溶酶体区室和对 BCL-XL 抑制的超敏反应。然而，持久性细胞缺乏衰老的其他特征，例如核纤层蛋白 B1 的缺失、衰老相关的 β-半乳糖苷酶活性、MHC-I 的上调以及炎症和分泌表型 （SASP）。对持久性细胞存活所需基因的全基因组 CRISPR/Cas9 筛选显示，它们对一碳 （1C） 代谢的抑制过敏，这可以通过 SHMT 的药理学抑制得到验证，SHMT 是一种将丝氨酸中的甲基馈送到 1C 代谢的关键酶。将 1C 代谢与转录的表观遗传调控联系起来，抑制性异色性标记 H4K20me3 在持久性细胞中 SASP 和干扰素反应基因的启动子处富集，而在增殖或衰老细胞中则不存在。此外，持久性细胞过表达 H4K20 甲基转移酶 KMT5B/C，它们的下调释放炎症程序并损害持久性细胞的存活。 总之，这项研究定义了持续性癌细胞的独特特征，确定了可操作的脆弱性，并提供了对其低炎症活性的机制见解。