Wang Yi-Chang, Kelso Andrew A, Karamafrooz Adak, Chen Yi-Hsuan, Chen Wei-Kai, Cheng Chun-Ting, Qi Yue, Gu Long, Malkas Linda, Kung Hsing-Jien, Moldovan George-Lucian, Ciccia Alberto, Stark Jeremy M, Ann David K
Department of Diabetes Complications and Metabolism, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute, City of Hope, Duarte, CA 91010, USA.
Irell & Manella Graduate School of Biological Sciences, City of Hope, Duarte, CA 91010, USA.
bioRxiv. 2023 Feb 3:2023.01.31.526362. doi: 10.1101/2023.01.31.526362.
The unique arginine dependencies of cancer cell proliferation and survival creates metabolic vulnerability. Here, we investigate the impact of extracellular arginine availability on DNA replication and genotoxic resistance. Using DNA combing assays, we find that when extracellular arginine is limited, cancer cells are arrested at S-phase and DNA replication forks slow or stall instantly until arginine is re-supplied. The translation of new histone H4 is arginine-dependent and impacts DNA replication and the expression of newly synthesized histone H4 is reduced in the avascular nutrient-poor breast cancer xenograft tumor cores. Furthermore, we demonstrate that increased PCNA occupancy and HLTF-catalyzed PCNA K63-linked polyubiquitination protects arginine-starved cells from hydroxyurea-induced, DNA2-catalyzed nascent strand degradation. Finally, arginine-deprived cancer cells are tolerant to genotoxic insults in a PCNA K63-linked polyubiquitination-dependent manner. Together, these findings reveal that extracellular arginine is the "linchpin" for nutrient-regulated DNA replication. Such information could be leveraged to expand current modalities or design new drug targets against cancer.
癌细胞增殖和存活对精氨酸的独特依赖性造成了代谢脆弱性。在此，我们研究细胞外精氨酸可用性对DNA复制和基因毒性抗性的影响。使用DNA梳理分析，我们发现当细胞外精氨酸有限时，癌细胞停滞在S期，DNA复制叉立即减慢或停滞，直到精氨酸重新供应。新组蛋白H4的翻译依赖于精氨酸，并且影响DNA复制，在无血管、营养贫乏的乳腺癌异种移植肿瘤核心中，新合成的组蛋白H4的表达降低。此外，我们证明，PCNA占有率的增加以及HLTF催化的PCNA K63连接的多聚泛素化可保护精氨酸饥饿的细胞免受羟基脲诱导的、DNA2催化的新生链降解。最后，精氨酸剥夺的癌细胞以PCNA K63连接的多聚泛素化依赖性方式耐受基因毒性损伤。总之，这些发现揭示细胞外精氨酸是营养调节DNA复制的“关键”。此类信息可用于扩展当前的治疗方式或设计针对癌症的新药物靶点。
