Department of Biology, School of Sciences and Humanities, Nazarbayev University, Kabanbay Batyr 53, Astana 010000, Kazakhstan.
Biomolecules. 2024 Nov 4;14(11):1401. doi: 10.3390/biom14111401.
Leucine is an essential amino acid that cannot be produced endogenously in the human body and therefore needs to be obtained from dietary sources. Leucine plays a pivotal role in stimulating muscle protein synthesis, along with isoleucine and valine, as the group of branched-chain amino acids, making them one of the most popular dietary supplements for athletes and gym-goers. The individual effects of leucine, however, have not been fully clarified, as most of the studies so far have focused on the grouped effects of branched-chain amino acids. In recent years, leucine and its metabolites have been shown to stimulate muscle protein synthesis mainly via the mammalian target of the rapamycin complex 1 signaling pathway, thereby improving muscle atrophy in cancer cachexia. Interestingly, cancer research suggests that leucine may have either anti-cancer or pro-tumorigenic effects. In the current manuscript, we aim to review leucine's roles in muscle protein synthesis, tumor suppression, and tumor progression, specifically summarizing the molecular mechanisms of leucine's action. The role of leucine is controversial in hepatocellular carcinoma, whereas its pro-tumorigenic effects have been demonstrated in breast and pancreatic cancers. In summary, leucine being used as nutritional supplement for athletes needs more attention, as its pro-oncogenic effects may have been identified by recent studies. Anti-cancer or pro-tumorigenic effects of leucine in various cancers should be further investigated to achieve clear conclusions.
亮氨酸是一种必需氨基酸，人体自身无法合成，因此需要从饮食中获取。亮氨酸与异亮氨酸和缬氨酸一起作为支链氨基酸，在刺激肌肉蛋白质合成中起着关键作用，是运动员和健身爱好者最常用的膳食补充剂之一。然而，亮氨酸的单独作用尚未完全阐明，因为迄今为止的大多数研究都集中在支链氨基酸的分组作用上。近年来，亮氨酸及其代谢物已被证明主要通过哺乳动物雷帕霉素靶蛋白复合物 1 信号通路刺激肌肉蛋白质合成，从而改善癌症恶病质中的肌肉萎缩。有趣的是，癌症研究表明亮氨酸可能具有抗癌或促肿瘤的作用。在本手稿中，我们旨在综述亮氨酸在肌肉蛋白质合成、肿瘤抑制和肿瘤进展中的作用，具体总结亮氨酸作用的分子机制。亮氨酸在肝细胞癌中的作用存在争议，但其在乳腺癌和胰腺癌中的促肿瘤作用已得到证实。总之，亮氨酸作为运动员的营养补充剂需要更多的关注，因为最近的研究已经确定了其致癌作用。需要进一步研究亮氨酸在各种癌症中的抗癌或促肿瘤作用，以得出明确的结论。
