SIRT1: a novel regulator in colorectal cancer

Targeting the NAD+/SIRT1 axis: A metabolic strategy to overcome oxaliplatin resistance in colorectal cancer

Oxaliplatin resistance remains a significant clinical challenge in colorectal cancer (CRC), highlighting the urgent need to identify novel molecular targets for therapeutic intervention. Recent findings by Niu et al have elucidated the role of the NAD+/SIRT1 axis in mediating oxaliplatin resistance through metabolic reprogramming. Their study demonstrated that oxaliplatin-induced DNA damage activates PARP, resulting in NAD+ depletion and subsequent downregulation of SIRT1. This reduction in SIRT1 levels enhances glycolysis, as evidenced by increased expression of PKM2 and LDHA, thereby conferring a metabolic advantage to resistant CRC cells. Conversely, restoration of SIRT1 expression reverses resistance, while pharmacological inhibition of glycolysis effectively sensitizes cells to oxaliplatin. These findings underscore the therapeutic potential of targeting the NAD+/SIRT1 pathway as a metabolic vulnerability in CRC. Future studies should investigate the clinical feasibility of combining SIRT1 agonists and glycolysis inhibitors with oxaliplatin to overcome drug resistance and improve patient outcomes.

Recent Advances on the Role of B Vitamins in Cancer Prevention and Progression

Water-soluble B vitamins, mainly obtained through dietary intake of fruits, vegetables, grains, and dairy products, act as co-factors in various biochemical processes, including DNA synthesis, repair, methylation, and energy metabolism. These vitamins include B1 (Thiamine), B2 (Riboflavin), B3 (Niacin), B5 (Pantothenic Acid), B6 (Pyridoxine), B7 (Biotin), B9 (Folate), and B12 (Cobalamin). Recent studies have shown that besides their fundamental physiological roles, B vitamins influence oncogenic metabolic pathways, including glycolysis (Warburg effect), mitochondrial function, and nucleotide biosynthesis. Although deficiencies in these vitamins are associated with several complications, emerging evidence suggests that excessive intake of specific B vitamins may also contribute to cancer progression and interfere with therapy due to impaired metabolic and genetic functions. This review discusses the tumor-suppressive and tumor-progressive roles of B vitamins in cancer. It also explores the recent evidence on a comprehensive understanding of the relationship between B vitamin metabolism and cancer progression and underscores the need for further research to determine the optimal balance of B vitamin intake for cancer prevention and therapy.