Comprehensive Cancer Center Mainfranken, University Hospital Würzburg, Versbacher Str. 5, 97078, Würzburg, Germany.
Sci Rep. 2020 Oct 28;10(1):18419. doi: 10.1038/s41598-020-75499-3.
Experimental evidence suggests that ubiquitin-protein ligases regulate a number of cellular processes involved in tumorigenesis. We analysed the role of the E3 ubiquitin-protein ligase HUWE1 for pathobiology of multiple myeloma (MM), a still incurable blood cancer. mRNA expression analysis indicates an increase in HUWE1 expression levels correlated with advanced stages of myeloma. Pharmacologic as well as RNAi-mediated HUWE1 inhibition caused anti-proliferative effects in MM cell lines in vitro and in an MM1.S xenotransplantation mouse model. Cell cycle analysis upon HUWE1 inhibition revealed decreased S phase cell fractions. Analyses of potential HUWE1-dependent molecular functions did not show involvement in MYC-dependent gene regulation. However, HUWE1 depleted MM cells displayed increased DNA tail length by comet assay, as well as changes in the levels of DNA damage response mediators such as pBRCA1, DNA-polymerase β, γH2AX and Mcl-1. Our finding that HUWE1 might thus be involved in endogenous DNA repair is further supported by strongly enhanced apoptotic effects of the DNA-damaging agent melphalan in HUWE1 depleted cells in vitro and in vivo. These data suggest that HUWE1 might contribute to tumour growth by endogenous repair of DNA, and could therefore potentially be exploitable in future treatment developments.
实验证据表明，泛素蛋白连接酶调控了许多参与肿瘤发生的细胞过程。我们分析了 E3 泛素蛋白连接酶 HUWE1 在多发性骨髓瘤（MM）发病机制中的作用，多发性骨髓瘤是一种仍无法治愈的血液癌。mRNA 表达分析表明，HUWE1 表达水平的增加与骨髓瘤的晚期阶段相关。在体外和 MM1.S 异种移植小鼠模型中，HUWE1 的药理学和 RNAi 介导抑制均导致 MM 细胞系的抗增殖作用。HUWE1 抑制后的细胞周期分析显示 S 期细胞分数减少。对潜在的 HUWE1 依赖性分子功能的分析并未显示其参与 MYC 依赖性基因调控。然而，HUWE1 耗尽的 MM 细胞在彗星试验中显示出 DNA 尾部长度增加，以及 DNA 损伤反应调节剂如 pBRCA1、DNA 聚合酶 β、γH2AX 和 Mcl-1 的水平发生变化。我们的研究结果表明，HUWE1 可能通过内源性 DNA 修复参与其中，这进一步得到了体外和体内实验中 HUWE1 耗尽细胞中 DNA 损伤剂美法仑增强凋亡作用的支持。这些数据表明，HUWE1 可能通过内源性 DNA 修复促进肿瘤生长，因此在未来的治疗开发中可能具有潜力。
