The SMAC mimetic LCL-161 selectively targets JAK2V617F mutant cells
The SMAC mimetic LCL-161 selectively targets JAK2V617F mutant cells
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DOI：
10.1186/s40164-019-0157-6
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发表时间：
2020-01-02
影响因子：
10.9
通讯作者：
Fleischman, Angela G.
中科院分区：
文献类型：
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作者：
Craver, Brianna M.;Thanh Kim Nguyen;Fleischman, Angela G.
背景 逃避程序性细胞死亡是癌症的一个标志，可以通过凋亡蛋白抑制剂 (IAP) 的过度表达在癌细胞中实现。第二种线粒体衍生的半胱天冬酶激活剂（SMAC）直接与 IAP 结合并促进细胞凋亡；因此，SMAC 模拟物已在多种癌症类型中进行了研究。特别是在炎症和 NFB 高度激活的疾病中。鉴于 TNF α 水平升高和 NF kappa B 激活是骨髓增生性肿瘤 (MPN) 的特征，我们研究了 SMAC 模拟物 LCL-161 对 MPN 细胞体外存活和体内疾病发展的影响。方法 为了研究 SMAC 模拟 LCL-161 的体外效果，我们利用小鼠和人类细胞系进行细胞活力测定，并利用 JAK2(V617F) 驱动的 MPN 小鼠或人类的原代骨髓来检测骨髓集落形成。为了阐明 SMAC 模拟物 LCL-161 的体内作用，我们用 LCL-161 治疗 JAK2(V617F) 驱动的 MPN 小鼠模型，然后评估血细胞计数、脾肿大和骨髓纤维化。结果我们发现，在没有外源 TNF α 的情况下，JAK2(V617F) 突变细胞对 SMAC 模拟物 LCL-161 高度敏感。 JAK2 激酶活性和 NF kappa B 激活是 JAK2(V617F) 介导的 LCL-161 敏感性所必需的，因为 JAK 或 NF kappa B 抑制剂降低了 JAK2(V617F) 突变细胞对 IAP 抑制的差异敏感性。最后，LCL-161 可减少 JAK2(V617F) 驱动的 MPN 小鼠模型中的脾肿大并可能减少纤维化。结论 LCL-161 可能对 MPN 具有治疗作用，特别是当外源性 TNF α 信号传导被阻断时。 NF kappa B 激活是 JAK2(V617F) 突变细胞的一个特征，即使在没有 TNF α 的情况下，这也使它们对 SMAC 模拟物诱导的杀伤敏感。然而，当添加外源 TNF α 时，突变型和野生型细胞中的 NF kappa B 都会被激活，从而消除了差异敏感性。此外，JAK激酶活性是JAK2(V617F)突变细胞的差异敏感性所必需的，这表明向SMAC模拟物中添加JAK2抑制剂会降低SMAC模拟物选择性靶向JAK2(V617F)突变细胞的能力。相反，与其他减少炎症细胞因子但保留突变细胞中 JAK2 信号传导的药物联合治疗可能是 MPN 中更有益的联合治疗。
Background Evasion from programmed cell death is a hallmark of cancer and can be achieved in cancer cells by overexpression of inhibitor of apoptosis proteins (IAPs). Second mitochondria-derived activator of caspases (SMAC) directly bind to IAPs and promote apoptosis; thus, SMAC mimetics have been investigated in a variety of cancer types. particularly in diseases with high inflammation and NFB activation. Given that elevated TNF alpha levels and NF kappa B activation is a characteristic feature of myeloproliferative neoplasms (MPN), we investigated the effect of the SMAC mimetic LCL-161 on MPN cell survival in vitro and disease development in vivo. Methods To investigate the effect of the SMAC mimetic LCL-161 in vitro, we utilized murine and human cell lines to perform cell viability assays as well as primary bone marrow from mice or humans with JAK2(V617F)-driven MPN to interrogate myeloid colony formation. To elucidate the effect of the SMAC mimetic LCL-161 in vivo, we treated a JAK2(V617F)-driven mouse model of MPN with LCL-161 then assessed blood counts, splenomegaly, and myelofibrosis. Results We found that JAK2(V617F)-mutated cells are hypersensitive to the SMAC mimetic LCL-161 in the absence of exogenous TNF alpha. JAK2 kinase activity and NF kappa B activation is required for JAK2(V617F)-mediated sensitivity to LCL-161, as JAK or NF kappa B inhibitors diminished the differential sensitivity of JAK2(V617F) mutant cells to IAP inhibition. Finally, LCL-161 reduces splenomegaly and may reduce fibrosis in a mouse model of JAK2(V617F)-driven MPN. Conclusion LCL-161 may be therapeutically useful in MPN, in particular when exogenous TNF alpha signaling is blocked. NF kappa B activation is a characteristic feature of JAK2(V617F) mutant cells and this sensitizes them to SMAC mimetic induced killing even in the absence of TNF alpha. However, when exogenous TNF alpha is added, NF kappa B is activated in both mutant and wild-type cells, abolishing the differential sensitivity. Moreover, JAK kinase activity is required for the differential sensitivity of JAK2(V617F) mutant cells, suggesting that the addition of JAK2 inhibitors to SMAC mimetics would detract from the ability of SMAC mimetics to selectively target JAK2(V617F) mutant cells. Instead, combination therapy with other agents that reduce inflammatory cytokines but preserve JAK2 signaling in mutant cells may be a more beneficial combination therapy in MPN.