MicroRNA-1291 effects on pancreatic cancer (PC) cells sensitivity to arginine deprivation and chemotherapy through modulation of ASS1 and GLUT1.

Abstract

334 Background: Cancer cells are reprogrammed to become addicted to a continuous supply of nutritional glucose and semi-essential amino acids like arginine, to drive synthesis of critical macromolecules for proliferation, tumorigenesis and metastasis. This dependence on nutritional supply makes cancer cells potentially vulnerable to deprivation by agents like pegylated arginine deiminase (ADI-PEG) which converts arginine back to citrulline. However, this vulnerability depends on limited ability of cancer cells to make arginine. PC cells that express high levels of argininosuccinate synthase 1 (ASS1), the rate limiting enzyme in cellular arginine synthesis, appear to be resistant to ADI-PEG. Our recent study showed that miR-1291 modulates factors in nutrient metabolism including ASS1 and GLUT1. We have developed a novel method to bioengineer miR-1291 agents for treatment. The aim of the current study was to evaluate if miR-1291 could enhance efficacy of metabolism-targeting drugs in PC. Methods: Cell proliferation was measured by CellTiter-Glo assay. Mature miR-1291 levels were determined by stem-loop reverse transcription real-time PCR assay. GLUT1 and ASS1 protein levels in miR-1291-treated pancreatic cancer cell lines were assessed by Western blot. Glucose uptake in AsPC-1 and PANC-1 cell lines was determined with a fluorescent probe, 2-NBDG. Results: A bioengineered pre-miR-1291 was processed to high levels of mature miR-1291 in PC cells. L3.3 and PANC-1 cells endogenously express high levels of ASS-1 and are resistant to arginine deprivation by ADI-PEG. ASS1 protein was downregulated by miR-1291 in L3.3 and PANC-1 cells and sensitized pancreatic cancer cells to ADI-PEG. In addition, miR-1291 significantly downregulated the protein levels of GLUT1 in AsPC-1 cells, leading to a lower glucose uptake capacity and a greater sensitivity to chemotherapy. Conclusions: Our results demonstrate that miR-1291 sensitizes PC cells to arginine deprivation and chemotherapy through downregulation of ASS1 and GLUT1. These results provide new insight into the mechanistic actions of miR-1291 and provide a new strategy for treatment of pancreatic cancer.