ITGA3 promotes pancreatic cancer progression through HIF1α- and c-Myc-driven glycolysis in a collagen I-dependent autocrine manner.

Pancreatic cancer is characterized by severe metabolic stress due to its prominent desmoplasia and poor vascularization. Integrin subunit alpha 3 (ITGA3) is a cell surface adhesion protein involved in tumor progression. However, the role of ITGA3 in pancreatic cancer progression, especially in metabolic reprogramming, remains largely unknown. In this study, we found that ITGA3 expression is elevated in pancreatic cancer tissues and predicts poor prognosis for patients with pancreatic cancer. Functional assays revealed that ITGA3 promotes the growth and liver metastasis of pancreatic cancer via boosting glycolysis. Mechanistically, Collagen I (Col1) derived from cancer cells acts as a ligand for ITGA3 to activate the FAK/PI3K/AKT/mTOR signaling pathway in an autocrine manner, thereby increasing the expression of HIF1α and c-Myc, two critical regulators of glycolysis. Blockade of Col1 by siRNA or of ITGA3 by a blocking antibody leads to specific inactivation of the FAK/PI3K/AKT/mTOR pathway and impairs malignant tumor behaviors induced by ITGA3. Thus, our data indicate that ITGA3 enhances glycolysis to promote pancreatic cancer growth and metastasis via increasing HIF1α and c-Myc expression in a Col1-dependent autocrine manner, making ITGA3 as a candidate diagnostic biomarker and a potential therapeutic target for pancreatic cancer.