HuR posttranscriptionally regulates WEE1: implications for the DNA damage response in pancreatic cancer cells.
HuR posttranscriptionally regulates WEE1: implications for the DNA damage response in pancreatic cancer cells.
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DOI：
10.1158/0008-5472.can-13-1915
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发表时间：
2014-02-15
期刊：
影响因子：
11.2
通讯作者：
Brody JR
中科院分区：
文献类型：
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作者：
Lal S;Burkhart RA;Beeharry N;Bhattacharjee V;Londin ER;Cozzitorto JA;Romeo C;Jimbo M;Norris ZA;Yeo CJ;Sawicki JA;Winter JM;Rigoutsos I;Yen TJ;Brody JR
HuR（ELAV 1）是一种在癌细胞中丰富的RNA结合蛋白，主要存在于细胞核中，但在特定的应激（例如，吉西他滨），HuR易位至细胞质，在细胞质中其紧密调节mRNA存活货物的表达。在此，我们首次证明，通过用DNA损伤抗癌剂（丝裂霉素C、奥沙利铂、顺铂、卡铂和PARP抑制剂）处理来强调胰腺导管腺癌（PDA）细胞导致HuR从细胞核易位到细胞质。重要的是，沉默PDA细胞中的HuR使细胞对这些药物敏感，而过表达HuR则导致耐药性。HuR在DNA损伤剂在PDA细胞中的功效中的作用部分归因于HuR对WEE 1的急性上调。WEE 1是一种有丝分裂抑制剂激酶，调节DNA损伤修复途径，WEE 1的治疗性抑制与化疗联合目前处于治疗癌症的早期试验中。我们通过证明：（1）HuR与WEE 1的mRNA（位于3 'UTR中的一个离散的56 bp区域）直接结合，以及（2）HuR siRNA沉默和过表达直接影响WEE 1的蛋白水平，特别是在DNA损伤后，验证了WEE 1作为HuR靶点的体外和体内作用。HuR对WEE 1的正性调节增加γ H2 AX水平，诱导Cdk 1磷酸化并促进细胞周期停滞在G2/M转换。我们描述了一种新的机制，PDA细胞利用保护免受DNA损伤，其中HuR转录后调节WEE 1的表达和下游功能，暴露于DNA损伤剂。
HuR (ELAV1), an RNA binding protein abundant in cancer cells, primarily resides in the nucleus, but under specific stress (e.g., gemcitabine), HuR translocates to the cytoplasm where it tightly modulates the expression of mRNA survival cargo. Herein, we demonstrate for the first time that stressing pancreatic ductal adenocarcinoma (PDA) cells by treatment with DNA damaging anti-cancer agents (mitomycin C, oxaliplatin, cisplatin, carboplatin and a PARP-inhibitor) results in HuR’s translocation from the nucleus to the cytoplasm. Importantly, silencing HuR in PDA cells sensitized the cells to these agents, while overexpressing HuR caused resistance. HuR’s role in the efficacy of DNA damaging agents in PDA cells was, in part, attributed to the acute upregulation of WEE1 by HuR. WEE1, a mitotic inhibitor kinase, regulates the DNA damage repair pathway, and therapeutic inhibition of WEE1 in combination with chemotherapy is currently in early phase trials for the treatment of cancer. We validate WEE1 as a HuR target in vitro and in vivo by demonstrating: (1) direct binding of HuR to WEE1’s mRNA (a discrete 56-bp region residing in the 3’UTR), and (2) HuR siRNA silencing and overexpression directly affects the protein levels of WEE1, especially after DNA damage. HuR’s positive regulation of WEE1 increases γH2AX levels, induces Cdk1-phosphorylation and promotes cell cycle arrest at the G2/M transition. We describe a novel mechanism that PDA cells utilize to protect against DNA damage in which HuR post-transcriptionally regulates the expression and downstream function of WEE1 upon exposure to DNA damaging agents.