Mitochondrial DNA depletion sensitizes cancer cells to PARP inhibitors by translational and post-translational repression of BRCA2.
Mitochondrial DNA depletion sensitizes cancer cells to PARP inhibitors by translational and post-translational repression of BRCA2.
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DOI：
10.1038/oncsis.2013.45
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发表时间：
2013-12-16
期刊：
影响因子：
6.2
通讯作者：
Moro, L.
中科院分区：
文献类型：
--
作者：
Arbini, A. A.;Guerra, F.;Greco, M.;Marra, E.;Gandee, L.;Xiao, G.;Lotan, Y.;Gasparre, G.;Hsieh, J-T;Moro, L.
以前的研究表明，药物抑制聚（ADP-核糖）聚合酶（PARP），一种在信号单链DNA断裂中至关重要的核蛋白，对DNA修复蛋白BRCA 1和BRCA 2遗传缺陷患者的癌细胞具有合成致死性。在本文中，我们证明了乳腺、前列腺和甲状腺转化细胞中线粒体基因组（mtDNA）的缺失导致稳态细胞溶质钙浓度升高和钙调磷酸酶/PI 3-激酶/AKT信号传导的激活，导致miR-1245和泛素连接酶Skp 2（肿瘤抑制蛋白BRCA 2的两种有效负调节剂）的上调，从而导致BRCA 2蛋白缺失，同源重组（HR）严重减少，对PARP抑制剂rucaparib的敏感性增加。用PI 3激酶抑制剂LY 294002、钙调蛋白拮抗剂W-7、钙调磷酸酶抑制剂FK 506、钙螯合剂BAPTA-AM处理mtDNA耗尽的细胞，或通过AKT小干扰RNA（siRNA）抑制AKT活性，提高BRCA 2蛋白水平以及HR。或通过重组表达或通过Skp 2和miR-1245的小分子抑制直接重建BRCA 2蛋白水平，将对rucaparib的敏感性恢复到野生型水平。此外，通过研究前列腺癌患者的前列腺组织标本，我们发现体内mtDNA大缺失和BRCA 2蛋白缺失之间存在直接相关性，这表明mtDNA状态可以作为预测PARP抑制剂治疗效果的标志物。总之，我们的研究结果揭示了一种新的机制，mtDNA耗尽抑制HR，并强调了mtDNA在调节转化细胞对PARP抑制剂的敏感性中的作用。
Previous studies have shown that pharmacologic inhibition of poly (ADP-ribose) polymerase (PARP), a nuclear protein that is crucial in signaling single-strand DNA breaks, is synthetically lethal to cancer cells from patients with genetic deficiency in the DNA repair proteins BRCA1 and BRCA2. Herein, we demonstrate that depletion of the mitochondrial genome (mtDNA) in breast, prostate and thyroid transformed cells resulted in elevated steady-state cytosolic calcium concentration and activation of calcineurin/PI3-kinase/AKT signaling leading to upregulation of miR-1245 and the ubiquitin ligase Skp2, two potent negative regulators of the tumor suppressor protein BRCA2, thus resulting in BRCA2 protein depletion, severe reduction in homologous recombination (HR) and increased sensitivity to the PARP inhibitor rucaparib. Treatment of mtDNA-depleted cells with the PI3-kinase inhibitor LY294002, the calmodulin antagonist W-7, the calcineurin inhibitor FK506, the calcium chelator BAPTA-AM, or suppression of AKT activity by AKT small-interfering RNA (siRNA) enhanced BRCA2 protein levels as well as HR. Decreasing the intracellular calcium levels using BAPTA, or direct reconstitution of BRCA2 protein levels either by recombinant expression or by small molecule inhibition of both Skp2 and miR-1245 restored sensitivity to rucaparib to wild-type levels. Furthermore, by studying prostate tissue specimens from prostate carcinoma patients we found a direct correlation between the presence of mtDNA large deletions and loss of BRCA2 protein in vivo, suggesting that mtDNA status may serve as a marker to predict therapeutic efficacy to PARP inhibitors. In summary, our results uncover a novel mechanism by which mtDNA depletion restrains HR, and highlight the role of mtDNA in regulating sensitivity to PARP inhibitors in transformed cells.
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DOI：
10.1158/1940-6207.capr-10-0326
发表时间：
2011-05
期刊：
Cancer prevention research (Philadelphia, Pa.)
影响因子：
--
作者：
Chatterjee A;Dasgupta S;Sidransky D
通讯作者：
Sidransky D
影响因子：
56.9
作者：
Ishikawa, Kaori;Takenaga, Keizo;Hayashi, Jun-Ichi
通讯作者：
Hayashi, Jun-Ichi
影响因子：
16
作者：
Davies, AA;Masson, JY;West, SC
通讯作者：
West, SC
影响因子：
11.4
作者：
Biswas, G;Adebanjo, OA;Avadhani, NG
通讯作者：
Avadhani, NG
影响因子：
3.5
作者：
Guerra, Flora;Kurelac, Ivana;Gasparre, Giuseppe
通讯作者：
Gasparre, Giuseppe