Upregulation of pyruvate kinase M2 expression by fatty acid synthase contributes to gemcitabine resistance in pancreatic cancer

Pancreatic cancer has one of the highest mortality rates of all cancer types. Fatty acid synthase (FASN) is a multifunctional protein homodimer that can convert acetyl coenzyme A (CoA) and malonyl-CoA into palmitate, thus regulating lipogenesis. FASN overexpression has also been shown to cause resistance to gemcitabine, a chemotherapy treatment for pancreatic cancer; however, the mechanism by which this happens is unclear. Analysis of gene expression of FASN and pyruvate kinase M2 (PKM2) in pancreatic cancer was performed using Oncomine microarray gene expression datasets, which demonstrated that FASN and PKM2 were upregulated in pancreatic cancer compared with normal tissue. Specifically, it was demonstrated that FASN enabled the upregulation of PKM2 expression at the mRNA and protein levels, increasing the glucose consumption rate in pancreatic cancer cells. The present study also revealed that decreased levels of FASN reduced resistance to gemcitabine treatment, which was induced by PKM2 overexpression in pancreatic ductal adenocarcinoma cells. Therefore, FASN may represent a novel therapeutic target in pancreatic cancer.