Knockout of ENO1 leads to metabolism reprogramming and tumor retardation in pancreatic cancer.

The shift in glucose utilization from oxidative phosphorylation to glycolysis is the hallmark of tumor cells. The overexpression of ENO1, one of the key enzymes in the glycolysis process, has been identified in several cancers, however, its role in pancreatic cancer (PC) is yet unclear. This study identifies ENO1 as an indispensable factor in the progression of PC. Interestingly, ENO1-knockout could inhibit cell invasion and migration and prevent cell proliferation in pancreatic ductal adenocarcinoma (PDAC) cells (PANC-1 and MIA PaCa-2); meanwhile, tumor cell glucose uptake and lactate excretion also decreased significantly. Furthermore, ENO1-knockout reduced colony formation and tumorigenesis in both in vitro and in vivo tests. In total, after ENO1 knockout, 727 differentially expressed genes (DEGs) were identified in PDAC cells by RNA-seq. Gene Ontology enrichment analysis revealed that these DEGs are mainly associated with components such as the 'extracellular matrix' and 'endoplasmic reticulum lumen', and participate in the regulation of signal receptor activity. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that the identified DEGs are associated with pathways, such as 'fructose and mannose metabolism', 'pentose phosphate pathway, and 'sugar metabolism for amino and nucleotide. Gene Set Enrichment Analysis showed that ENO1 knockout promoted the upregulation of oxidative phosphorylation and lipid metabolism pathways-related genes. Altogether, these results indicated that ENO1-knockout inhibited tumorigenesis by reducing cell glycolysis and activating other metabolic pathways by altering the expression of G6PD, ALDOC, UAP1, as well as other related metabolic genes. Concisely, ENO1, which plays a vital role in the abnormal glucose metabolism in PC, can be exploited as a target to control carcinogenesis by reducing aerobic glycolysis.

Calcium Channel α2δ1 is Essential for Pancreatic Tumor-Initiating Cells through Sequential Phosphorylation of PKM2.

BACKGROUND & AIMS: Tumor-initiating cells (TICs) drive pancreatic cancer tumorigenesis, therapeutic resistance, and metastasis. However, TICs are highly plastic and heterogenous, which impede the robust identification and targeted therapy of such a population. The aim of this study is to identify the surface marker and therapeutic target for pancreatic TICs. METHODS: We isolated voltage-gated calcium channel α2δ1 subunit (isoform 5)-positive subpopulation from pancreatic cancer cell lines and freshly resected primary tissues by fluorescence-activated cell sorting and evaluated their TIC properties by spheroid formation and tumorigenic assays. Coimmunoprecipitation was used to identify the direct substrate of CaMKⅡδ. RESULTS: We demonstrate that the voltage-gated calcium channel α2δ1 subunit (isoform 5) marks a subpopulation of pancreatic TICs with the highest TIC frequency among the known pancreatic TIC markers tested. Furthermore, α2δ1 is functionally sufficient and indispensable to promote TIC properties by mediating Ca2+ influx, which activates CaMKⅡδ to directly phosphorylate PKM2 at T454 that results in subsequent phosphorylation at Y105 to translocate into nucleus, enhancing the stem-like properties. Interestingly, blocking α2δ1 with its specific antibody has remarkably therapeutic effects on pancreatic cancer xenografts by reducing TICs. CONCLUSIONS: α2δ1 promotes pancreatic TIC properties through sequential phosphorylation of PKM2 mediated by CaMKⅡδ, and targeting α2δ1 provides a therapeutic strategy against TICs for pancreatic cancer.