Succinate dehydrogenase deficiency-driven succinate accumulation induces drug resistance in acute myeloid leukemia via ubiquitin-cullin regulation

Drug resistance is vital for the poor prognosis of acute myeloid leukemia (AML) patients, but the underlying mechanism remains poorly understood. Given the unique microenvironment of bone marrow, we reasoned that drug resistance of AML might rely on distinct microenvironment-associated metabolic processes. Here, we identified SDH deficiency and over-cumulative succinate as typical features in AML, with a marked function in causing the resistance of AML cells to a wide range of anti-cancer therapies. Mechanistically, succinate promoted the accumulation of oncogenic proteins in a manner that precedes transcriptional activation. This function was mediated by succinate-triggered upregulation of UBC12 phosphorylation, which impaired its E2 function in cullins neddylation. Notably, decreasing succinate levels by fludarabine could effectively restore the drug sensitivity of SDH-deficient AML PDX. Together, we uncover a novel function of succinate in driving drug resistance by regulating p-UBC12/cullin activity, and indicate reshaping succinate metabolism as a promising treatment for SDH-deficient AML. HL-60 cells were treated with 6 mM succinate for 3 h or 24 h and then harvested. SDHA is knocked down in HL-60 cells using lentiviral infection, followed by two rounds of puromycin selection to establish stable SDHA knockdown cell lines. RNA sequencing was then actualized and analyzed.

药物耐药性与急性髓系白血病（acute myeloid leukemia, AML）患者的不良预后密切相关，但其潜在分子机制仍有待深入解析。鉴于骨髓微环境的独特性，我们推测AML的药物耐药性可能依赖于与微环境相关的特异性代谢通路。本研究发现，琥珀酸脱氢酶（succinate dehydrogenase, SDH）功能缺陷与琥珀酸过度蓄积是AML的典型特征，且二者可显著导致AML细胞对多种抗肿瘤治疗产生耐药性。从机制层面来看，琥珀酸可在转录激活之前促进致癌蛋白的蓄积。该功能通过琥珀酸诱导UBC12磷酸化水平上调介导，而UBC12磷酸化上调会损害其在cullin蛋白NEDD8修饰过程中的E2酶活性。值得注意的是，通过氟达拉滨降低琥珀酸水平，可有效恢复SDH缺陷型AML患者来源异种移植模型（patient-derived xenograft, PDX）的药物敏感性。综上，本研究揭示了琥珀酸通过调控磷酸化UBC12/cullin活性进而介导药物耐药的全新功能，并提示重塑琥珀酸代谢可作为SDH缺陷型AML的潜在治疗策略。将HL-60细胞用6 mM琥珀酸分别处理3小时或24小时后收集细胞；采用慢病毒感染技术在HL-60细胞中敲低SDHA（succinate dehydrogenase complex flavoprotein subunit A, SDHA），随后通过两轮嘌呤霉素筛选构建稳定敲低SDHA的细胞系，随后对样本进行RNA测序并开展数据分析。