Serine metabolism reprogramming in cancer: a multi-tiered regulatory framework

As a critical component of amino acid metabolic reprogramming, serine metabolism has been demonstrated to be enhanced in a variety of cancer types, thereby supporting tumor progression. This enhancement is primarily driven by increased expression levels and augmented enzymatic activity of serine metabolic enzymes (phosphoglycerate dehydrogenase, phosphoserine aminotransferase 1, phosphoserine phosphatase and serine hydroxymethyltransferase). However, there is still lack of comprehensive summary on the regulation of serine metabolism in cancer. In this review, we provide a systematic overview of the currently discovered and proven regulatory mechanisms of serine metabolic enzymes in cancer, focusing on three levels: transcriptional, post-transcriptional, and post-translational regulation. Specifically, transcriptional regulation encompasses three major mechanisms: (1) transcription factor-mediated gene expression control, (2) histone modifications, and (3) DNA methylation. At the post-transcriptional level, regulation is primarily achieved through (1) non-coding RNAs, (2) RNA-binding proteins, and (3) RNA modifications. Post-translational regulation is predominantly mediated through diverse protein post-translational modifications. The transcriptional and post-transcriptional mechanisms primarily modulate the expression levels of serine metabolic enzymes, while post-translational modifications exert more diverse effects by altering the activity, protein stability or cellular localization of these enzymes. These regulations collectively modulate serine metabolism to influence tumor progression, offering promising targets for tumor-specific therapeutic interventions.