SMARCA2 和 SMARCA4 参与 DNA 损伤修复。

SMARCA2 and SMARCA4 Participate in DNA Damage Repair.

机构信息

Department of Biological Sciences, University of Chicago, Chicago, IL 60637, USA.

SynRx Therapeutics, Chicago, IL 60642, USA.

出版信息

Front Biosci (Landmark Ed). 2024 Jul 23;29(7):262. doi: 10.31083/j.fbl2907262.

DOI:10.31083/j.fbl2907262

PMID:39082357

Abstract

BACKGROUND

The switching/sucrose non-fermentable (SWI/SNF) Related, Matrix Associated, Actin Dependent Regulator Of Chromatin, Subfamily A (SMARCA) member 2 and member 4 (SMARCA2/4) are paralogs and act as the key enzymatic subunits in the SWI/SNF complex for chromatin remodeling. However, the role of SMARCA2/4 in DNA damage response remains unclear.

METHODS

Laser microirradiation assays were performed to examine the key domains of SMARCA2/4 for the relocation of the SWI/SNF complex to DNA lesions. To examine the key factors that mediate the recruitment of SMARCA2/4, the relocation of SMARCA2/4 to DNA lesions was examined in HeLa cells treated with inhibitors of Ataxia-telangiectasia-mutated (ATM), Ataxia telangiectasia and Rad3-related protein (ATR), CREB-binding protein (CBP) and its homologue p300 (p300/CBP), or Poly (ADP-ribose) polymerase (PARP) 1/2 as well as in H2AX-deficient HeLa cells. Moreover, by concomitantly suppressing SMARCA2/4 with the small molecule inhibitor FHD286 or Compound 14, the function of SMARCA2/4 in Radiation sensitive 51 (RAD51) foci formation and homologous recombination repair was examined. Finally, using a colony formation assay, the synergistic effect of PARP inhibitors and SMARCA2/4 inhibitors on the suppression of tumor cell growth was examined.

RESULTS

We show that SMARCA2/4 relocate to DNA lesions in response to DNA damage, which requires their ATPase activities. Moreover, these ATPase activities are also required for the relocation of other subunits in the SWI/SNF complex to DNA lesions. Interestingly, the relocation of SMARCA2/4 is independent of γH2AX, ATM, ATR, p300/CBP, or PARP1/2, indicating that it may directly recognize DNA lesions as a DNA damage sensor. Lacking SMARCA2/4 prolongs the retention of γH2AX, Ring Finger Protein 8 (RNF8) and Breast cancer susceptibility gene 1 (BRCA1) at DNA lesions and impairs RAD51-dependent homologous recombination repair. Furthermore, the treatment of an SMARCA2/4 inhibitor sensitizes tumor cells to PARP inhibitor treatment.

CONCLUSIONS

This study reveals SMARCA2/4 as a DNA damage repair factor for double-strand break repair.

摘要

背景

开关/蔗糖非发酵（SWI/SNF）相关、基质相关、肌动蛋白依赖性染色质调节剂亚家族 A（SMARCA）成员 2 和成员 4（SMARCA2/4）是同源物，作为染色质重塑 SWI/SNF 复合物的关键酶亚基。然而，SMARCA2/4 在 DNA 损伤反应中的作用尚不清楚。

方法

激光微照射实验用于研究 SMARCA2/4 的关键结构域，以研究 SWI/SNF 复合物向 DNA 损伤的重定位。为了研究介导 SMARCA2/4 募集的关键因素，在使用 ATM 抑制剂、ATR 抑制剂、CBP 及其同源物 p300（p300/CBP）、或聚（ADP-核糖）聚合酶 1/2（PARP1/2）抑制剂处理的 HeLa 细胞中以及在 H2AX 缺陷型 HeLa 细胞中，研究了 SMARCA2/4 向 DNA 损伤的重定位。此外，通过同时用小分子抑制剂 FHD286 或化合物 14 抑制 SMARCA2/4，研究了 SMARCA2/4 在 RAD51 焦点形成和同源重组修复中的功能。最后，通过集落形成实验，研究了 PARP 抑制剂和 SMARCA2/4 抑制剂对肿瘤细胞生长抑制的协同作用。

结果

我们表明，SMARCA2/4 在 DNA 损伤后会重新定位到 DNA 损伤部位，这需要它们的 ATP 酶活性。此外，这些 ATP 酶活性对于 SWI/SNF 复合物的其他亚基向 DNA 损伤的重定位也是必需的。有趣的是，SMARCA2/4 的重定位不依赖于 γH2AX、ATM、ATR、p300/CBP 或 PARP1/2，表明它可能直接作为 DNA 损伤传感器识别 DNA 损伤。缺乏 SMARCA2/4 会延长 γH2AX、环指蛋白 8（RNF8）和乳腺癌易感基因 1（BRCA1）在 DNA 损伤部位的滞留时间，并损害 RAD51 依赖性同源重组修复。此外，SMARCA2/4 抑制剂的处理可使肿瘤细胞对 PARP 抑制剂治疗敏感。