pSer784-VCP: a clinically relevant link between autophagy and DNA damage response

项目总结 自噬和DNA损伤反应(DDR)是进化上保守的两个基本重要的 手机节目。这两种药物都可以在癌症中放松管制，进而作为癌症治疗的靶向。尽管 令人信服的证据表明，自噬和DDR是相关的，与DDR相关的已知数量很少 自噬目标极大地限制了我们对其功能串扰的理解。关于这一事件的报道褒贬不一 自噬激活的化疗增敏效应强烈地表明， 自噬在DDR中的生理作用。我们假设这种上下文依赖关系可以通过以下方式确定 受影响的DDR自噬靶标的功能重要性。在这笔赠款中，我们将重点放在一个重要的 DDR因子称为VCP。VCP是一种普遍表达的AAA+ATPase，它识别多泛素化 并通过泛素-蛋白酶体和自噬/溶酶体途径促进蛋白质的降解。 我们最近的工作表明，DNA损伤诱导的Ser784磷酸化选择性地增加了核VCP 用于DDR的函数。重要的是，pSer784-VCP是化疗后乳腺癌预后差的标志物 病人。这些数据表明，靶向pSer784-VCP可能是一种新的有效的化学增敏作用 接近。在这项研究中，我们提供了初步的数据，表明pSer784-VCP可能是以前的 无法识别的自噬目标。在目标1中，我们将定义特定的自噬途径，它涉及 PSer784-VCP降解并寻找pSer784-VCP经历核出口的直接证据 DNA损伤。在目标2中，我们将在一组三阴性的乳腺癌细胞系中测试DNA 损伤诱导的pSer784-VCP水平预测自噬调节剂的化学增敏效应。一起， 这些实验将提高我们对自噬和DDR之间的功能串扰的理解， 并帮助定义这两个细胞程序的共同靶向的生物学背景 对治疗有益。

PROJECT SUMMARY Autophagy and DNA damage response (DDR) are two evolutionarily conserved, fundamentally important cellular programs. Both can be deregulated in cancer and in turn targeted as cancer therapies. Despite compelling evidence that autophagy and DDR are connected, the scarce number of known DDR-relevant autophagy targets greatly limits our understanding of their functional crosstalk. Mixed reports regarding the chemotherapy-sensitizing effect of autophagy activation strongly suggest the context-dependency of the physiological role of autophagy in DDR. We hypothesize that this context-dependency could be determined by the functional importance of the affected autophagy targets for DDR. In this grant, we focus on an important DDR factor named VCP. VCP is a ubiquitously expressed AAA+ ATPase which recognizes polyubiquitinated proteins and facilitates their degradation by both the ubiquitin-proteasome and autophagy/lysosome pathways. Our recent work showed that DNA damage-induced Ser784 phosphorylation selectively increases nuclear VCP function for DDR. Importantly, pSer784-VCP is poor prognostic marker for chemotherapy-treated breast cancer patients. These data suggest that targeting pSer784-VCP may be a novel and effective chemo-sensitizing approach. In this grant, we present preliminary data showing that pSer784-VCP may be a previously unrecognized target of autophagy. In Aim 1, we will define the specific autophagy pathway that is involved in pSer784-VCP degradation and seek for direct evidence that pSer784-VCP undergoes nuclear export upon DNA damage. In Aim 2, we will test in a large panel of triple-negative breast cancer cell lines whether DNA damage-induced pSer784-VCP levels predict chemo-sensitizing effects of autophagy modulators. Together, these experiments will improve our understanding of the functional crosstalk between autophagy and DDR, and help define the biological context within which co-targeting of these two cellular programs can be therapeutically beneficial.