Fasting inhibits glycolysis and migration/invasion in gallbladder cancer via PCBP2/ANGPTL4 signaling

Gallbladder cancer (GBC) is a biliary tract cancer with a poor prognosis. Consistent evidence suggests that fasting has extensive antitumor effects in various cancers and influences levels of poly (rC)-binding protein 2 (PCBP2). However, whether fasting and PCBP2 are involved in GBC remains unknown. We assessed the expression of PCBP2 in GBC tumor tissues and cells. Knockdown and overexpression of PCBP2, combined with in vitro and in vivo assays using fasting mimic medium or diets, were conducted to provide functional significance. The effect of PCBP2 on glycolysis was assessed by glucose uptake, lactate production, oxygen consumption rate, and limiting glycolytic-associated enzymes (PDK1, PKM2, and HK-2). We found that fasting could inhibit glycolysis and cell migration/invasion in GBC cells and that fasting mimic diets could significantly inhibit GBC cell proliferation in a mouse xenograft model. PBCP2 was upregulated in GBC tumor tissues and cells. Moreover, PCBP2 is a key downstream target of fasting, and fasting decreases PCBP2 expression in GBC cells. PCBP2 knockdown inhibits GBC cell proliferation, migration/invasion, and glycolysis, whereas PCBP2 overexpression has the opposite effect. Through co-immunoprecipitation, we identified a physical connection between PCBP2 and the angiopoietin-like protein ANGPTL4. PCBP2 can negatively regulate the expression of ANGPTL4. Hence, fasting inhibits cell proliferation, migration/invasion, and glycolysis through PCBP2/ANGPTL4 signaling. We conclude that PCBP2 is a target of fasting and is involved in cell migration/invasion and glycolysis through the negative regulation of ANGPTL4 in GBC. PCBP2 represents a potential therapeutic target for GBC.