NF-κB inhibition sensitizes to starvation-induced cell death in high-risk myelodysplastic syndrome and acute myeloid leukemia
NF-κB inhibition sensitizes to starvation-induced cell death in high-risk myelodysplastic syndrome and acute myeloid leukemia
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DOI：
10.1038/sj.onc.1210187
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发表时间：
2007-06-14
期刊：
影响因子：
8
通讯作者：
Kroemer, G.
中科院分区：
文献类型：
--
作者：
Fabre, C.;Carvalho, G.;Kroemer, G.
来自高危骨髓增生异常综合征 (MDS) 患者的 CD34(+) 骨髓母细胞以及 MDS 患者来源的细胞系（P39 和 MOLM13）持续激活核因子-κ B (NF-κ B) 通路，并在 NF-κ B 受到抑制时发生细胞凋亡。在这里，我们证明传统化疗药物（柔红霉素、米托蒽醌、5-氮杂胞苷或喜树碱）与 NF-κ B 抑制剂 BAY11-7082 的组合不会产生协同细胞毒性。相比之下，BAY11-7082（靶向NF-kappa B激活I-kappa B激酶（IKK）复合物）或通过小干扰RNA敲低NF-kappa B系统的重要组成部分（例如IKK复合物的IKK1和IKK2亚基以及NF-kappa B的p65亚基）使MDS细胞系对饥饿诱导的细胞凋亡敏感。 BAY11-7082 与营养消耗的组合可协同杀死急性髓系白血病 (AML) 细胞系 U937 以及 AML 和高危 MDS 患者的原代 CD34+ 骨髓母细胞。 BAY11-7082 的协同杀伤作用与营养消耗相结合，导致细胞死亡，并伴有细胞凋亡的所有特征，包括线粒体跨膜电位的早期丧失、线粒体释放细胞色素 c 和凋亡诱导因子 (AIF)、caspase-3 激活、质膜表面磷脂酰丝氨酸暴露和核染色质浓缩。透射电子显微镜显示，在细胞发生核凋亡之前，细胞质中存在大量自噬空泡。尽管如此，细胞死亡既不能被泛半胱天冬酶抑制剂 z-VAD-fmk 抑制，也不能被 AIF 或自噬途径重要成分（ATG5、ATG6/Beclin-1、ATG10、ATG12）的敲低所抑制。相反，外部供应葡萄糖、胰岛素或胰岛素样生长因子-I可以延缓BAY11-7082联合饥饿诱导的细胞死亡。这些结果表明，在 MDS 细胞中，NF-κ B 抑制可引发生物能量危机，导致自噬应激反应，随后导致细胞凋亡。
CD34(+) bone marrow blasts from high-risk myelodysplastic syndrome (MDS) patients as well as MDS patient-derived cell lines (P39 and MOLM13) constitutively activate the nuclear factor-kappa B (NF-kappa B) pathway and undergo apoptosis when NF-kappa B is inhibited. Here, we show that the combination of conventional chemotherapeutic agents (daunorubicin, mitoxantrone, 5-azacytidine or camptothecin) with the NF-kappa B inhibitor BAY11-7082 did not yield a synergistic cytotoxicity. In contrast, BAY11-7082 (which targets the NF-kappa B-activating I-kappa B kinase (IKK) complex) or knockdown of essential components of the NF-kappa B system (such as the IKK1 and IKK2 subunits of the IKK complex and the p65 subunit of NF-kappa B), by small interfering RNAs sensitized MDS cell lines to starvation-induced apoptosis. The combination of BAY11-7082 and nutrient depletion synergistically killed the acute myeloid leukemia (AML) cell line U937 as well as primary CD34+ bone marrow blasts from AML and high-risk MDS patients. The synergistic killing by BAY11-7082, combined with nutrient depletion, led to cell death accompanied by all hallmarks of apoptosis, including an early loss of the mitochondrial transmembrane potential, the release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria, activation of caspase-3, phosphatidylserine exposure on the plasma membrane surface and nuclear chromatin condensation. Transmission electron microscopy revealed the presence of numerous autophagic vacuoles in the cytoplasm before cells underwent nuclear apoptosis. Nonetheless, cell death was neither inhibited by the pan-caspase inhibitor z-VAD-fmk nor by knockdown of AIF or of essential components of the autophagy pathway (ATG5, ATG6/ Beclin-1, ATG10, ATG12). In contrast, external supply of glucose, insulin or insulin-like growth factor-I could retard the cell death induced by BAY11-7082 combined with starvation. These results suggest that in MDS cells, NF-kappa B inhibition can precipitate a bioenergetic crisis that leads to an autophagic stress response followed by apoptotic cell death.