Degradation of 5hmC-marked stalled replication forks by APE1 causes genomic instability.
Degradation of 5hmC-marked stalled replication forks by APE1 causes genomic instability.
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DOI：
10.1126/scisignal.aba8091
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发表时间：
2020-08-18
影响因子：
7.3
通讯作者：
Sharan SK
中科院分区：
文献类型：
--
作者：
Kharat SS;Ding X;Swaminathan D;Suresh A;Singh M;Sengodan SK;Burkett S;Marks H;Pamala C;He Y;Fox SD;Buehler EC;Muegge K;Martin SE;Sharan SK
聚（adp -核糖）聚合酶（PARP）抑制和BRCA缺乏之间的合成致死性被用于治疗乳腺和卵巢肿瘤。然而，PARP抑制剂耐药（PARPi）是常见的。为了确定潜在的耐药机制，我们在brca2缺陷小鼠胚胎干细胞中进行了全基因组RNAi筛选，并在KB2P1.21小鼠乳腺肿瘤细胞中进行了验证。我们发现，对多种PARPi的抗性出现在TET2表达减少（10 - 11易位），TET2通过将5-甲基胞嘧啶（5mC）氧化为5-羟甲基胞嘧啶（5hmC）和其他产物来促进DNA去甲基化。由于双链断裂（dsb）位点的5hmC数量减少，brca2缺陷细胞中的TET2敲低保护了停滞复制叉（RFs）。增加5hmC丰度通过募集与BRCA2状态无关的碱基切除修复相关的无嘌呤/无嘧啶内切酶APE1，诱导KB2P1.21和人类癌细胞中停滞的RFs降解。TET2缺失不影响修复蛋白RAD51在dsb位点的募集，也不影响与RF完整性或BRCA2状态相关的蛋白丰度。TET2及其产物5hmc的缺失，以及APE1的募集导致RFs停滞，促进了对顺铂化疗的耐药。我们的研究结果揭示了表观遗传标记5hmC在维持停滞RFs完整性方面的未知作用，以及对PARPi和顺铂的潜在耐药机制。
Synthetic lethality between poly(ADP-ribose) polymerase (PARP) inhibition and BRCA deficiency is exploited to treat breast and ovarian tumors. However, resistance to PARP inhibitors (PARPi) is common. To identify potential resistance mechanisms, we performed a genome-wide RNAi screen in BRCA2-deficient mouse embryonic stem cells and validation in KB2P1.21 mouse mammary tumor cells. We found that resistance to multiple PARPi emerged with reduced expression of TET2 (ten eleven translocation), which promotes DNA demethylation by oxidizing 5-methylcytosine (5mC) to 5-hydroxymethycytosine (5hmC) and other products. TET2 knockdown in BRCA2-deficient cells protected stalled replication forks (RFs) due to reduced 5hmC amounts at sites of double-stranded breaks (DSBs). Increasing 5hmC abundance induced the degradation of stalled RFs in KB2P1.21 and human cancer cells by recruiting the base excision repair-associated apurinic/apyrimidinic endonuclease APE1, independent of the BRCA2 status. TET2 loss did not affect the recruitment of the repair protein RAD51 to sites of DSBs or the abundance of proteins associated with RF integrity, or BRCA2 status. The loss of TET2, of its product 5hmc, and of APE1 recruitment to stalled RFs promoted resistance to the chemotherapeutic cisplatin. Our findings reveal a previously unknown role for the epigenetic mark 5hmC in maintaining the integrity of stalled RFs and a potential resistance mechanism to PARPi and cisplatin.
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影响因子：
64.8
作者：
Ray Chaudhuri A;Callen E;Ding X;Gogola E;Duarte AA;Lee JE;Wong N;Lafarga V;Calvo JA;Panzarino NJ;John S;Day A;Crespo AV;Shen B;Starnes LM;de Ruiter JR;Daniel JA;Konstantinopoulos PA;Cortez D;Cantor SB;Fernandez-Capetillo O;Ge K;Jonkers J;Rottenberg S;Sharan SK;Nussenzweig A
通讯作者：
Nussenzweig A
影响因子：
21.3
作者：
Dev H;Chiang TW;Lescale C;de Krijger I;Martin AG;Pilger D;Coates J;Sczaniecka-Clift M;Wei W;Ostermaier M;Herzog M;Lam J;Shea A;Demir M;Wu Q;Yang F;Fu B;Lai Z;Balmus G;Belotserkovskaya R;Serra V;O'Connor MJ;Bruna A;Beli P;Pellegrini L;Caldas C;Deriano L;Jacobs JJL;Galanty Y;Jackson SP
通讯作者：
Jackson SP
影响因子：
20.3
作者：
Biswas, Kajal;Das, Ranabir;Sharan, Shyam K.
通讯作者：
Sharan, Shyam K.
影响因子：
8
作者：
Graham K;Unger E
通讯作者：
Unger E
影响因子：
64.5
作者：
Cimmino L;Dolgalev I;Wang Y;Yoshimi A;Martin GH;Wang J;Ng V;Xia B;Witkowski MT;Mitchell-Flack M;Grillo I;Bakogianni S;Ndiaye-Lobry D;Martín MT;Guillamot M;Banh RS;Xu M;Figueroa ME;Dickins RA;Abdel-Wahab O;Park CY;Tsirigos A;Neel BG;Aifantis I
通讯作者：
Aifantis I