BACKGROUND Since iPSC human develop into hepatic organoids through stages that resemble human embryonic liver development, they can be used to study developmental processes and disease pathology. Therefore, we examined the early stages of hepatic organoid formation to identify key pathways affecting early liver development. METHODS Single cell RNA-sequencing and metabolomic analysis was performed on developing organoid cultures at the iPSC, hepatoblast (day 9) and mature organoid stage. The importance of the phosphatidyl-ethanolamine biosynthesis pathway to early liver development was examined in developing organoid cultures using iPSC with a CRISPR-mediated gene knockout and an over the counter medication (meclizine) that inhibits the rate-limiting enzyme in this pathway. Meclizine's effect on the growth of a human hepatocarcinoma cell line in a xenotransplantation model and on the growth of acute myeloid leukemia cells in vitro was also examined. RESULTS Transcriptomic and metabolomic analysis of organoid development indicated that the phosphatidyl-ethanolamine biosynthesis pathway is essential for early liver development. Unexpectedly, early hepatoblasts were selectively sensitive to the cytotoxic effect of meclizine. We demonstrate that meclizine could be repurposed for use in a new synergistic combination therapy for primary liver cancer: a glycolysis inhibitor reprograms cancer cell metabolism to make it susceptible to the cytotoxic effect of meclizine. This combination inhibited the growth of a human liver carcinoma cell line in vitro; and in a xenotransplantation model without causing significant side effets. This drug combination was also highly active against acute myeloid leukemic cells. CONCLUSION Our data indicates that the phosphatidyl-ethanolamine biosynthesis is a targetable pathway for cancer; and that meclizine may have clinical efficacy as a repurposed anti-cancer drug when used as part of a new combination therapy.

中文翻译：

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磷脂酰乙醇胺生物合成途径为癌症化疗提供新靶点

背景 由于 iPSC 人类通过类似于人类胚胎肝脏发育的阶段发育成肝脏类器官，因此它们可用于研究发育过程和疾病病理学。因此，我们检查了肝脏类器官形成的早期阶段，以确定影响早期肝脏发育的关键途径。方法 对处于 iPSC、成肝细胞（第 9 天）和成熟类器官阶段的类器官培养物进行单细胞 RNA 测序和代谢组学分析。在使用具有 CRISPR 介导的基因敲除的 iPSC 和抑制该途径中限速酶的非处方药（meclizine）开发类器官培养物中，检查了磷脂酰乙醇胺生物合成途径对早期肝脏发育的重要性。Meclizine' 还检查了对异种移植模型中人肝癌细胞系生长和体外急性髓性白血病细胞生长的影响。结果类器官发育的转录组学和代谢组学分析表明，磷脂酰乙醇胺生物合成途径对于早期肝脏发育至关重要。出乎意料的是，早期成肝细胞对氯苯甲嗪的细胞毒作用选择性敏感。我们证明 meclizine 可以重新用于原发性肝癌的新协同联合疗法：糖酵解抑制剂重新编程癌细胞代谢，使其对 meclizine 的细胞毒性作用敏感。这种组合在体外抑制了人肝癌细胞系的生长；并且在异种移植模型中不会引起显着的副作用。这种药物组合对急性髓性白血病细胞也具有高度活性。结论 我们的数据表明，磷脂酰乙醇胺的生物合成是癌症的靶向途径；并且当作为新组合疗法的一部分使用时，meclizine 可能具有作为重新利用的抗癌药物的临床疗效。