CRCHUM, 900 Saint-Denis St, Montréal, QC H2X 0A9, Canada; Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3C 3J7, Canada.
Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3C 3J7, Canada.
Mol Cell. 2021 Sep 16;81(18):3848-3865.e19. doi: 10.1016/j.molcel.2021.08.028.
Metabolic rewiring and redox balance play pivotal roles in cancer. Cellular senescence is a barrier for tumorigenesis circumvented in cancer cells by poorly understood mechanisms. We report a multi-enzymatic complex that reprograms NAD metabolism by transferring reducing equivalents from NADH to NADP. This hydride transfer complex (HTC) is assembled by malate dehydrogenase 1, malic enzyme 1, and cytosolic pyruvate carboxylase. HTC is found in phase-separated bodies in the cytosol of cancer or hypoxic cells and can be assembled in vitro with recombinant proteins. HTC is repressed in senescent cells but induced by p53 inactivation. HTC enzymes are highly expressed in mouse and human prostate cancer models, and their inactivation triggers senescence. Exogenous expression of HTC is sufficient to bypass senescence, rescue cells from complex I inhibitors, and cooperate with oncogenic RAS to transform primary cells. Altogether, we provide evidence for a new multi-enzymatic complex that reprograms metabolism and overcomes cellular senescence.
代谢重编程和氧化还原平衡在癌症中起着关键作用。细胞衰老(cellular senescence)是肿瘤发生的障碍,但其中的机制仍不甚清楚,癌症细胞会绕过这一障碍。我们报告了一种多酶复合物,它通过将还原当量从 NADH 转移到 NADP 来重新编程 NAD 代谢。这种氢转移复合物(HTC)由苹果酸脱氢酶 1、苹果酸酶 1 和细胞质丙酮酸羧化酶组装而成。HTC 存在于癌症或缺氧细胞细胞质的相分离体中,并且可以用重组蛋白在体外组装。HTC 在衰老细胞中受到抑制,但被 p53 失活所诱导。HTC 酶在小鼠和人类前列腺癌模型中高度表达,其失活会引发衰老。外源性表达 HTC 足以绕过衰老,使细胞免受复合物 I 抑制剂的影响,并与致癌性 RAS 合作转化原代细胞。总的来说,我们提供了证据表明存在一种新的多酶复合物,它可以重新编程代谢并克服细胞衰老。
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