BTdCPU is a compound that exerts its function by activating the heme-regulated inhibitor (HRI) kinase. BTdCPU promotes the phosphorylation of eIF2α and induces cellular apoptosis[1-2]. BTdCPU holds potential in cancer research, particularly for the study of multiple myeloma and its drug-resistant subtypes[3-4].
In vitro, treatment of multiple myeloma cell lines (MM1.S, H929, MM1.R, RPMI8266, U266) and primary CD138+ cells derived from multiple myeloma patients with BTdCPU (10-20μM) for 4 or 48 hours activated the HRI kinase, induced phosphorylation of eIF2α, upregulated the expression of the pro-apoptotic protein CHOP, and triggered apoptosis[5]. When HEK293T cells, SHSY5Y cells, and Perk+/+ and Perk-/- MEFs were treated with BTdCPU (10μM) for 3 hours, BTdCPU induced mitochondrial membrane depolarization, activated the OMA1-DELE1-HRI mitochondrial stress signaling axis, led to mitochondrial fragmentation, and reduced ATP-linked respiration. This mitochondrial depolarization occurred independently of the integrated stress response (ISR) signaling[6].
In vivo, in a C57BL/6 leukemia mouse model bearing BCR-ABL+ B-ALL cells, intraperitoneal administration of BTdCPU (400mg/kg/day) combined with oral ABT-263 (100mg/kg/day) for 14 consecutive days (starting from day 5 post-transplantation), BTdCPU significantly prolonged the survival of leukemic mice, reduced peripheral white blood cell counts, suppressed MCL-1 protein expression, and upregulated ATF4 levels in the bone marrow[7]. In female nude mice carrying MCF-7 human breast cancer xenografts, intraperitoneal administration of BTdCPU (175mg/kg/day) for 21 consecutive days (starting from tumor transplantation), BTdCPU significantly inhibited tumor growth, induced complete tumor stasis, upregulated phosphorylated eIF2α protein levels in tumor tissues, and did not cause significant hematological toxicity or organ pathological damage[8].
References:
[1] Blázquez AB, Martín-Acebes MA, Poderoso T, et al. Relevance of oxidative stress in inhibition of eIF2 alpha phosphorylation and stress granules formation during Usutu virus infection. PLoS Negl Trop Dis. 2021 Jan 25;15(1):e0009072.
[2] Cuoco CA, Ren W, Baron KR, et al. Pharmacological targeting of RIG-I can selectively activate the integrated stress response. Sci Adv. 2025 Oct 31;11(44):eadt3014.
[3] Zhang C, Xu H, Tang Q, et al. CaMKII suppresses proteotoxicity by phosphorylating BAG3 in response to proteasomal dysfunction. EMBO Rep. 2024 Oct;25(10):4488-4514.
[4] Ogami K, Richard P, Chen Y, et al. An Mtr4/ZFC3H1 complex facilitates turnover of unstable nuclear RNAs to prevent their cytoplasmic transport and global translational repression. Genes Dev. 2017 Jun 15;31(12):1257-1271.
[5] Burwick N, Zhang MY, de la Puente P, et al. The eIF2-alpha kinase HRI is a novel therapeutic target in multiple myeloma. Leuk Res. 2017 Apr;55:23-32.
[6] Perea V, Baron KR, Dolina V, et al. Pharmacologic Activation of a Compensatory Integrated Stress Response Kinase Promotes Mitochondrial Remodeling in PERK-deficient Cells. bioRxiv [Preprint]. 2023 May 17:2023.03.11.532186.
[7] Smith KH, Budhraja A, Lynch J, et al. The Heme-Regulated Inhibitor Pathway Modulates Susceptibility of Poor Prognosis B-Lineage Acute Leukemia to BH3-Mimetics. Mol Cancer Res. 2021 Apr;19(4):636-650.
[8] Chen T, Ozel D, Qiao Y, et al. Chemical genetics identify eIF2α kinase heme-regulated inhibitor as an anticancer target. Nat Chem Biol. 2011 Jul 17;7(9):610-6.
BTdCPU是一种通过激活血红素调节抑制激酶（HRI）发挥作用的化合物，BTdCPU能够促进eIF2α的磷酸化，诱导细胞凋亡[1-2]。BTdCPU在癌症研究领域具有应用潜力，尤其适用于多发性骨髓瘤及其耐药亚型的研究[3-4]。
在体外，BTdCPU（10-20μM）处理多发性骨髓瘤细胞系（MM1.S、H929、MM1.R、RPMI8266、U266）和原代多发性骨髓瘤患者来源的CD138+细胞4小时或48小时，BTdCPU通过激活HRI激酶诱导eIF2α磷酸化，上调促凋亡蛋白CHOP的表达，并诱导细胞凋亡[5]。BTdCPU（10μM）处理HEK293T细胞、SHSY5Y细胞以及Perk+/+和Perk-/- MEFs 3小时，BTdCPU诱导线粒体膜电位去极化，激活OMA1-DELE1-HRI线粒体应激信号轴，导致线粒体碎片化，并降低ATP关联呼吸，但该线粒体去极化不依赖于整合应激反应（ISR）信号[6]。
在体内，BTdCPU（400mg/kg/day）腹腔注射处理携带BCR-ABL+ B-ALL细胞的C57/BL6白血病小模型（从移植后第5天开始，连续14天），BTdCPU与口服ABT-263（100mg/kg/day）联合治疗显著延长白血病小鼠的生存期，降低外周血白细胞计数，并诱导骨髓中MCL-1蛋白表达的抑制和ATF4的上调[7]。BTdCPU（175mg/kg/day）腹腔注射处理携带MCF-7人乳腺癌异种移植瘤的雌性裸鼠（从肿瘤移植后开始，连续21天），BTdCPU显著抑制肿瘤生长并诱导肿瘤完全停滞，同时上调肿瘤组织中磷酸化eIF2α蛋白表达水平，且未引起明显血液学毒性或器官病理损伤[8]。