GFAT1 is highly expressed in cancer stem cells of pancreatic cancer.

Background: Cancer stem cells (CSCs) play pivotal roles in the growth, invasion, metastasis, and chemoresistance of pancreatic cancer (PC). The current characterization of CSCs in PC is not complete. Glutamine-fructose-6-phosphate transaminase 1 (GFAT1) is a key enzyme that regulates the hexosamine pathway (HP), in which it not only controls glucose influx but also catalyzes the reaction to form glucosamine 6-phosphate. Recently, it was reported that GFAT1 is highly expressed in PC. However, the relevance of this high expression of GFAT1, especially its association with cancer stemness, has not been well defined and is thus addressed in the current study.

Methods: GFAT1 levels were determined in PC from a public database and assessed by bioinformatics tools. GFAT1 expression in CD133 and CD44 CSCs in PC was analyzed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunostaining on cytospun cells after flow cytometry-based cell sorting. GFAT1 cells were separated from GFAT1 cells by transfection of PC cell lines with a designed plasmid that expressed red fluorescent protein (RFP) under a GFAT1 promoter. Tumor sphere formation, tumor growth, tumor cell invasion, cell migration, and the resistance to gemcitabine-induced apoptosis were determined in GFAT1 GFAT1 PC cells.

Results: GFAT1 levels were significantly upregulated in PC compared to the adjacent non-PC tissue. There were significantly more GFAT1 cells in the CD133 population than in the CD133 population, and similarly, there were significantly more GFAT1 cells in the CD44 population than in the CD44 population. Compared to GFAT1 PC cells, GFAT1 PC cells generated significantly more tumor spheres in culture, appeared to be more invasive and migratory, and were significantly more resistant to gemcitabine-induced cell apoptosis.

Conclusions: GFAT1 is highly expressed in CSCs among PC cells and may be crucial for PC growth, metastasis, and chemoresistance.