Synergistic Loss of Prostate Cancer Cell Viability by Coinhibition of HDAC and PARP
Synergistic Loss of Prostate Cancer Cell Viability by Coinhibition of HDAC and PARP
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DOI：
10.1158/1541-7786.mcr-14-0173
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发表时间：
2014-12-01
影响因子：
5.2
通讯作者：
Goodman, Oscar B., Jr.
中科院分区：
文献类型：
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作者：
Chao, Olivia S.;Goodman, Oscar B., Jr.
BRCA种系突变的肿瘤在通过同源重组（HR）途径修复DNA双链断裂（DSB）方面存在缺陷，使其对PARP抑制剂（PARPi）敏感。然而，BRCA种系突变在前列腺癌中是罕见的，限制了治疗这些途径的能力。本研究探讨了组蛋白去乙酰化酶（HDAC）抑制剂（HDACi）是否可以下调DSB修复途径并使前列腺癌细胞对PARPi敏感。据报道，HDACi可以调节散发性癌症中的DSB修复途径。与单药治疗相比，HDAC抑制剂亚eroylanilide羟肟酸（SAHA）和PARPi奥拉帕尼共同治疗的前列腺癌细胞显示出细胞活力的协同降低（联合指数< 0.9），而正常前列腺细胞则没有。同样，共处理后克隆原性显著降低。流式细胞术细胞周期分析和Annexin-V染色显示SAHA+奥拉帕尼治疗后细胞凋亡显著。这与免疫荧光显微镜观察到的伽马H2AX灶（dsb的标记物）的DNA损伤增加相吻合。此外，免疫印迹分析显示核gH2AX水平显著且持续升高。SAHA和奥拉帕尼均下调hr相关蛋白BRCA1和RAD51的表达，而SAHA +奥拉帕尼对RAD51有累加作用。沉默RAD51使前列腺癌细胞对SAHA和奥拉帕尼敏感。总的来说，与HDACi和PARPi共同治疗降低了hr相关蛋白的表达，同时增加了DNA损伤，导致前列腺癌细胞死亡。AACR (C) 2014。
Tumors with BRCA germline mutations are defective in repairing DNA double-strand breaks (DSB) through homologous recombination (HR) pathways, making them sensitive to PARP inhibitors (PARPi). However, BRCA germline mutations are rare in prostate cancer limiting the ability to therapeutically target these pathways. This study investigates whether histone deacetylase (HDAC) inhibitors (HDACi), reported to modulate DSB repair pathways in sporadic cancers, can downregulate DSB repair pathways and sensitize prostate cancer cells to PARPi. Prostate cancer cells cotreated with the HDAC inhibitor, suberoylanilide hydroxamic acid (SAHA) and the PARPi, olaparib, demonstrated a synergistic decrease in cell viability compared with single-agent treatment (combination index < 0.9), whereas normal prostatic cells did not. Similarly, clonogenicity was significantly decreased after cotreatment. Flow cytometric cell-cycle analysis and Annexin-V staining revealed significant apoptosis upon treatment with SAHA+olaparib. This coincided with increased DNA damage observed by immunofluorescence microscopy analysis of gamma H2AX foci, a marker of DSBs. In addition, immunoblot analysis showed a significant and persistent increase in nuclear gH2AX levels. Both SAHA and olaparib downregulated the expression of HR-related proteins, BRCA1 and RAD51, whereas SAHA + olaparib had an additive effect on RAD51. Silencing RAD51 sensitized prostate cancer cells to SAHA and olaparib alone. Collectively, cotreatment with HDACi and PARPi downregulated HR-related protein expression and concomitantly increased DNA damage, resulting in prostate cancer cell death. (C)2014 AACR.