Chk1 inhibition as a novel therapeutic strategy in melanoma.
Chk1 inhibition as a novel therapeutic strategy in melanoma.
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DOI：
10.18632/oncotarget.25765
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发表时间：
2018-07-13
期刊：
影响因子：
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通讯作者：
Lu, A-Lien
中科院分区：
文献类型：
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作者：
Hwang, Bor-Jang;Adhikary, Gautam;Lu, A-Lien
黑色素瘤患者对化疗反应不佳，因为他们获得耐药性。迫切需要能够克服对黑色素瘤中突变的BRAF蛋白激酶抑制剂的抗性的疗法。Chk 1蛋白激酶是DNA损伤反应的核心成分，在控制细胞周期进程中起着至关重要的作用。分析表明，Chk 1的低mRNA表达与黑色素瘤患者的良好总体生存率显著相关。为了评价Chk 1抑制剂在黑色素瘤治疗中的有效性，我们分别从A375和WM 9产生了BRAF抑制剂（PLX 4032或维罗非尼）抗性黑色素瘤细胞系（A375-PLX-R和WM 9-PLX-R）。我们观察到AKT（蛋白激酶B）在A375-PLX-R细胞中被组成性激活，但在WM 9-PLX-R细胞中未被激活，这表明这些细胞通过不同的机制对PLX 4032产生耐药性。我们发现，一种有效的特异性Chk 1抑制剂（PF 477736）可有效降低PLX 4032耐药细胞的细胞活力和集落形成。更令人印象深刻的是，PF 477736触发PLX 4032抗性黑素瘤细胞重新获得对PLX 4032的敏感性。小鼠异种移植物研究显示，用组合的PLX 4032和PF 477736处理A375-PLX-R衍生的肿瘤显著降低肿瘤生长。PLX 4032和PF 477736的联合治疗降低了PLX 4032敏感和耐药黑色素瘤细胞中总Chk 1蛋白的水平，并改变了几个位点的Chk 1磷酸化。用PLX 4032和PF 477736对黑素瘤细胞的组合处理基本上诱导DNA损伤和细胞死亡。我们的研究结果表明，Chk 1抑制剂可能为黑色素瘤患者提供新的治疗选择。
Melanoma patients respond poorly to chemotherapies because they acquire drug resistance. Therapies that can overcome the resistance to inhibitors of the mutated BRAF protein kinase in melanoma are urgently needed. Chk1 protein kinase is a central component of the DNA damage response and plays a crucial role in controlling cell cycle progression. Analyses indicate that low mRNA expression of Chk1 is significantly associated with good overall survival of melanoma patients. To evaluate the effectiveness of Chk1 inhibitors in melanoma therapy, we have generated BRAF inhibitor (PLX4032 or vemurafenib) resistant melanoma cell lines (A375-PLX-R and WM9-PLX-R) from A375 and WM9, respectively. We observe that AKT (protein kinase B) is constitutively activated in A375-PLX-R, but not in WM9-PLX-R cells, suggesting that these cells develop resistance to PLX4032 through different mechanisms. We show that a potent and specific inhibitor of Chk1 (PF477736) is effective in reducing cell viability and colony formation of PLX4032-resistant cells. Even more impressively, PF477736 triggers PLX4032-resistant melanoma cells to regain sensitivity to the PLX4032. Mouse xenograft studies show that treating A375-PLX-R derived tumors with combined PLX4032 and PF477736 significantly reduce tumor growth. Combined treatments with PLX4032 and PF477736 reduce the levels of total Chk1 protein and alter Chk1 phosphorylation at several sites in both PLX4032 sensitive and resistant melanoma cells. Combinatorial treatments with PLX4032 and PF477736 to melanoma cells substantially induce DNA damage and cell death. Our results suggest that Chk1 inhibitors may provide new therapy options for melanoma patients.