Histone deacetylase (HDAC) inhibitor LBH589 increases duration of γ-H2AX foci and confines HDAC4 to the cytoplasm in irradiated non-small cell lung cancer
Histone deacetylase (HDAC) inhibitor LBH589 increases duration of γ-H2AX foci and confines HDAC4 to the cytoplasm in irradiated non-small cell lung cancer
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DOI：
10.1158/0008-5472.can-06-0049
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发表时间：
2006-12-01
期刊：
影响因子：
11.2
通讯作者：
Hallahan, Dennis E.
中科院分区：
文献类型：
--
作者：
Geng, Ling;Cuneo, Kyle C.;Hallahan, Dennis E.
组蛋白去乙酰化酶（HDAC）由于其在DNA结构和组织中的调节功能而被确定为治疗靶点。LBH 589是一种新型的I类和11类HDAC抑制剂。研究了LBH 589和电离辐射（IR）对两种人非小细胞肺癌（NSCLC）细胞系（H23和H460）DNA修复的影响。在3戈伊照射长达6小时后，在细胞核中检测到存在于DNA双链断裂（DSB）处的γ-H2 AX灶。照射前给予LBH 589增加γ-H2 AX病灶的持续时间超过24小时。此外，单独的辐射诱导HDAC 4易位到细胞核。相比之下，用LBH 589处理然后照射导致HDAC 4局限于细胞质，表明HDAC抑制影响HDAC 4的核定位。LBH 589将HDAC 4限制在细胞质中并增加辐照细胞系中γ-H2 AX焦点的持续时间的发现表明HDAC 4参与IR后的DNA损伤信号传导。Annexin-propidium iodide流式细胞术测定、细胞形态学研究和裂解的caspase-3蛋白质印迹分析揭示了LBB 589与IR在诱导细胞凋亡中的协同作用。与单独照射相比，在照射前给予LBH 589时，克隆形成存活率显示出大于累加效应。体内肿瘤体积研究显示，联合治疗的生长延迟为20天，而单独放疗或LBH 589的生长延迟为4天和2天。本研究将HDAC 4鉴定为LBH 589活性的生物标志物，并认识到LBH 589使人NSCLC对辐射诱导的DNA DSB敏感的能力。
Histone deacetylases (HDAC) have been identified as therapeutic targets due to their regulatory function in DNA structure and organization. LBH589 is a novel inhibitor of class I and 11 HDACs. We studied the effect of LBH589 and ionizing radiation (IR) on DNA repair in two human nonsmall cell lung cancer (NSCLC) cell lines (H23 and H460). gamma-H2AX foci present at DNA double-strand breaks (DSBs) were detected in the nuclei following 3 Gy irradiation for up to 6 hours. LBH589 administered before irradiation increased the duration of gamma-H2AX foci beyond 24 hours. Furthermore, radiation alone induced translocation of HDAC4 to the nucleus. In contrast, treatment with LBH589 followed by irradiation resulted in HDAC4 confinement to the cytoplasm, indicating that HDAC inhibition affects the nuclear localization of HDAC4. The findings that LBH589 confines HDAC4 to the cytoplasm and increases the duration of gamma-H2AX foci in irradiated cell lines suggest that HDAC4 participates in DNA damage signaling following IR. Annexin-propidium iodide flow cytometry assays, cell morphology studies, and cleaved caspase-3 Western blot analysis revealed a synergistic effect of LBB589 with IR in inducing apoptosis. Clonogenic survival showed a greater than additive effect when LBH589 was administered before irradiation compared with irradiation alone. In vivo tumor volume studies showed a growth delay of 20 days with combined treatment compared with 4 and 2 days for radiation or LBH589 alone. This study identifies HDAC4 as a biomarker of LBH589 activity and recognizes the ability of LBH589 to sensitize human NSCLC to radiation-induced DNA DSBs.