Department of Cell Biology and Anatomy, Arnie Charbonneau Cancer, Alberta Children's Hospital Research Institutes, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
Department of Marine Biotechnology, Gangneung-Wonju National University, Gangneung, South Korea.
Sci Rep. 2021 Jan 13;11(1):1009. doi: 10.1038/s41598-020-80520-w.
The search continues for improved therapy for acute lymphoblastic leukemia (aLL), the most common malignancy in children. Recently, D,L-methadone was put forth as sensitizer for aLL chemotherapy. However, the specific target of D,L-methadone in leukemic cells and the mechanism by which it induces leukemic cell apoptosis remain to be defined. Here, we demonstrate that D,L-methadone induces leukemic cell apoptosis through activation of the mu1 subtype of opioid receptors (OPRM1). D,L-Methadone evokes IP3R-mediated ER Ca release that is inhibited by OPRM1 loss. In addition, the rate of Ca extrusion following D,L-methadone treatment is reduced, but is accelerated by loss of OPRM1. These D,L-methadone effects cause a lethal rise in [Ca] that is again inhibited by OPRM1 loss, which then prevents D,L-methadone-induced apoptosis that is associated with activation of calpain-1, truncation of Bid, cytochrome C release, and proteolysis of caspase-3/12. Chelating intracellular Ca with BAPTA-AM reverses D,L-methadone-induced apoptosis, establishing a link between the rise in [Ca] and D,L-methadone-induced apoptosis. Altogether, our findings point to OPRM1 as a specific target of D,L-methadone in leukemic cells, and that OPRM1 activation by D,L-methadone disrupts IP3R-mediated ER Ca release and rate of Ca efflux, causing a rise in [Ca] that upregulates the calpain-1-Bid-cytochrome C-caspase-3/12 apoptotic pathway.
目前，仍在寻找治疗儿童中最常见恶性肿瘤——急性淋巴细胞白血病（ALL）的更佳疗法。最近，D,L-美沙酮被提出作为 ALL 化疗的增敏剂。然而，D,L-美沙酮在白血病细胞中的具体靶点以及其诱导白血病细胞凋亡的机制仍有待确定。在这里，我们证明 D,L-美沙酮通过激活μ1 型阿片受体（OPRM1）诱导白血病细胞凋亡。D,L-美沙酮引起 IP3R 介导的内质网 Ca 释放，而 OPRM1 的缺失可抑制这种释放。此外，D,L-美沙酮处理后 Ca 外排的速度会降低，但 OPRM1 的缺失会加速该过程。D,L-美沙酮的这些作用会导致致命的 [Ca]升高，而 OPRM1 的缺失又会抑制这种升高，从而阻止 D,L-美沙酮诱导的凋亡，这与钙蛋白酶-1 的激活、Bid 的截断、细胞色素 C 的释放以及 caspase-3/12 的蛋白水解有关。用 BAPTA-AM 螯合细胞内 Ca 可逆转 D,L-美沙酮诱导的凋亡，从而建立了 [Ca]升高与 D,L-美沙酮诱导的凋亡之间的联系。总的来说，我们的研究结果表明 OPRM1 是白血病细胞中 D,L-美沙酮的特定靶点，D,L-美沙酮激活 OPRM1 会破坏 IP3R 介导的内质网 Ca 释放和 Ca 外排速度，导致 [Ca]升高，从而上调钙蛋白酶-1-Bid-细胞色素 C-caspase-3/12 凋亡途径。
