Alteration of Cellular Energy Metabolism through LPAR2-Axin2 Axis in Gastric Cancer

Lysophosphatidic acid (LPA), a multifunctional endogenous phospholipid, plays a vital role in cellular homeostasis and the malignant behavior of cancer cells through G-protein-coupled receptors. However, the role of LPA in beta-catenin-mediated gastric cancer is unknown. Here, we have noted the high expression of LPAR2 in human gastric cancer tissues, and that LPA treatment significantly increased the proliferation, migration, and invasion of human gastric cancer cells. Results from our biochemical experiments showed that an LPA exposure increased the expression of beta-catenin and its nuclear localization, increased the phosphorylation of glycogen synthase kinase 3 beta (GSK-3 beta), decreased the expression of Axin2, and increased the expression of the target genes of the beta-catenin signaling pathway. The LPA2 receptor (LPAR2) antagonist significantly reduced the LPA-induced nuclear localization of beta-catenin, the primary signaling event. The knockdown of LPAR2 in the gastric cancer cell lines robustly reduced the LPA-induced beta-catenin activity. An LPA exposure increased the ATP production by both oxidative phosphorylation and glycolysis, and this effect was abrogated with the addition of an LPAR2 antagonist and XAV393, which stabilizes the Axin and inhibits the beta-catenin signaling pathway. Based on our findings, the possibility that LPA contributes to gastric cancer initiation and progression through the beta-catenin signaling pathway as well as by the dysregulation of the energy metabolism via the LPAR2 receptor and Axin2, respectively, provides a novel insight into the mechanism of and possible therapeutic targets of gastric cancer.

Automated summary

Lysophosphatidic acid (LPA) plays a critical role in beta-catenin-mediated gastric cancer by promoting proliferation, migration, and invasion of cancer cells. LPA exposure increases beta-catenin expression and nuclear localization, phosphorylation of GSK-3 beta, and target gene expression. LPA also affects energy metabolism and contributes to gastric cancer initiation and progression.