Introduction: Pancreatic adenocarcinoma (PDAC) is well known for its deregulated TGFβ signaling. TGFβ signaling exerts a contextual effect that suppresses malignant growth early in epithelial tumorigenesis but promotes metastasis at later stages. The Krüppel-like factor 10 (Klf10) is an early response gene that mediates the antiproliferative effects of TGFβ but opposes the prometastatic effects of TGFβ by limiting its ability to induce epithelial-to-mesenchymal transition (EMT). The distinction between the antiproliferative versus prometastatic functions of TGFβ makes Klf10 a potential target for the development of therapy in cancers with aberrant TGFβ pathway such as PDAC. Klf10 knock-out mice do not have abnormal pancreas development or carcinogenesis. However, ablating Klf10 in murine PDAC models increases pancreatic tumorigenesis and distant metastasis. Genome-wide comparison of mRNA profiles from wild-type and Klf10 knock-out mice revealed significant enrichment for transcripts involved in glucose metabolism. We propose that Klf10 modulates PDAC progression via enhanced glycolysis, which leads to EMT and cancer stemness phenotypes.

Materials and Methods: Genetically manipulated Klf10 of human PDAC cell lines was established to measure EMT markers, glycolysis activity and stemness related proteins, cell migration, and murine liver metastasis after intrasplenic injection. Chip-Chip assay was performed to find sirtuin 6 (Sirt6), governing both cancer metabolism and progression, to be one of the candidate molecules regulated by Klf10. The interaction between Klf10 and Sirt6 was evaluated by ChIP-PCR and luciferase reporter assay. PDAC cell lines with or without Klf10 mRNA silencing were overexpressed with Sirt6 to reverse malignant phenotypes induced by Klf10 deficiency. Linoleic acid, a specific Sirt6 activator, was used in vitro and in vivo to ameliorate the aberrant glucose metabolism, EMT phenotype, and distant metastasis of PDAC with loss of Klf10 expression.

Results: In vitro and in vivo studies demonstrated Klf10 deficiency in pancreatic cancer enhanced metastasis, EMT, stemness, and glycolysis. Klf10 bond to the promoter and transcriptionally regulated Sirt6. Sirt6 expression paralleled the level of Klf10 in PDAC. Modulating Sirt6 genetically or pharmacologically, by linoleic acid, reversed the EMT, glycolysis, and metastatic phenotypes of PDAC with KLF10 deficiency. Using PDK1, a glycolysis inhibitor, and BSI#38, an EMT inhibitor, we demonstrated the interaction of cancer metabolism and EMT phenotypes in PDAC.

Discussion: Loss of Klf10 contributes to pancreatic cancer progression and enhances glycolysis, EMT, and cancer stemness by transcriptionally regulating Sirt6. Overexpressing Sirt6 genetically or pharmacologically by linoleic acid may ameliorate PDAC progression. Targeting Klf10/Sirt6 signaling is a potential strategy to modulate glycolysis and EMT simultaneously in PDAC for preventing malignant progression.

Citation Format: Hui-Ju Ch'ang, Yi-Chih Tsai, Su-Liang Chen, Vincent H.S. Chang. Linoleic acid elevates sirtuin 6 expression and modulates glycolysis and epithelial-mesenchymal transition of pancreatic cancer with loss of Krüpple like factor 10 [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr C11.