Metformin activates KDM2A to reduce rRNA transcription and cell proliferation by dual regulation of AMPK activity and intracellular succinate level
Metformin activates KDM2A to reduce rRNA transcription and cell proliferation by dual regulation of AMPK activity and intracellular succinate level
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DOI：
10.1038/s41598-019-55075-0
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发表时间：
2019-12-10
影响因子：
4.6
通讯作者：
Tsuneoka, Makoto
中科院分区：
文献类型：
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作者：
Tanaka, Yuji;Konishi, Akimitsu;Tsuneoka, Makoto
二甲双胍用于治疗2型糖尿病。二甲双胍激活amp活化激酶（AMPK），这可能有助于二甲双胍的作用。二甲双胍还具有抗增殖活性。然而，其机制尚不清楚。我们发现二甲双胍处理MCF-7细胞诱导rDNA启动子中KDM2A的去甲基化酶活性，导致rRNA转录和细胞增殖减少。二甲双胍激活KDM2A需要AMPK活性。由于jmjc型酶的去甲基化酶活性需要将-酮戊二酸转化为琥珀酸盐的副反应，这些有机酸可能会影响它们的去甲基化酶活性。我们发现二甲双胍在α -酮戊二酸水平降低的情况下不会诱导KDM2A去甲基化酶活性。四小时的二甲双胍治疗特异性地降低了琥珀酸盐，琥珀酸盐的补充抑制了二甲双胍对KDM2A的激活，但没有抑制AMPK的激活。二甲双胍即使在抑制AMPK活性的条件下也能减少琥珀酸盐。这些结果表明，二甲双胍激活AMPK并降低细胞内琥珀酸盐水平，这两者都是激活KDM2A以减少rRNA转录所必需的。本文的研究结果揭示了二甲双胍作用的一个新因素，即细胞内琥珀酸盐的减少，这有助于二甲双胍的抗增殖活性。
Metformin is used to treat type 2 diabetes. Metformin activates AMP-activated kinase (AMPK), which may contribute to the action of metformin. Metformin also shows anti-proliferation activity. However, the mechanism is remained unknown. We found that treatment of MCF-7 cells with metformin induced the demethylase activity of KDM2A in the rDNA promoter, which resulted in reductions of rRNA transcription and cell proliferation. AMPK activity was required for activation of KDM2A by metformin. Because demethylase activities ofJmjC-type enzymes require a side reaction converting alpha-ketoglutarate to succinate, these organic acids may affect their demethylase activities. We found that metformin did not induce KDM2A demethylase activity in conditions of a reduced level of alpha-ketoglutarate. A four-hour treatment of metformin specifically reduced succinate, and the replenishment of succinate inhibited the activation of KDM2A by metformin, but did not inhibit the activation of AMPK. Metformin reduced succinate even in the conditions suppressing AMPK activity. These results indicate that metformin activates AMPK and reduces the intracellular succinate level, both of which are required for the activation of KDM2A to reduce rRNA transcription. The results presented here uncover a novel factor of metformin actions, reduction of the intracellular succinate, which contributes to the anti-proliferation activity of metformin.