Adenosine diphosphate-ribosylation factor-like 15 can regulate glycolysis and lipogenesis related genes in colon cancer.

Abstract

This study was designed to investigate the potential key genes of ADP-ribosylation factor-like 15 (ARL15) regulating glycolysis and lipogenesis in colon cancer. Hematoxylin-eosin (HE) staining and immunohistochemistry were used to observe the expression of ARL15 in 10 normal colon tissues and 10 colon cancer tissues. Immunofluorescence staining was used to observe the expression position of ARL15 in normal human colorectal mucosa cells (FHC) and colon cancer cells (HCT116 and SW620) with a confocal microscope. The ARL15 plasmid and small interfering RNA (siRNA) were constructed. After transfection, the expression levels of glycolysis and lipogenesis regulatory enzymes and messenger RNA (mRNA) transcription of ARL15 in over-expressed and silenced colon cancer cells were detected by Western blotting and real-time quantitative PCR (qRT-PCR). High expression of ARL15 in colon cancer tissue and low expression in normal colon tissue, and all expression are in the cytosol. The expression position of ARL15 in the FHC, HCT116, and SW620 cells was consistent and mainly distributed in the cytosol. After the pCMV-3Tag-2-ARL15 plasmid was transfected in HCT116, the protein expressions of FASN, AKT, P-AKT, P-GSK, SREBP-1 (p125) (p<0.01), and AMPK (p<0.001) were higher than those in the control group. The mRNA transcription level of FASN, GSK, AMPKa1, and SREBP-1 gene was higher than control group after the over-expression of ARL15. After the ARL15-siRNA was transfected in HCT116, the protein expression levels of PKM2, PFK, FASN, AKT, P-AKT, P-GSK, and AMPK decreased compared with the control group, (p<0.05). The mRNA transcription level of FASN, GSK, AMPKα1 gene was lower than control group after the low-expression of ARL15 (p<0.05). After adding 2 μM JIB-04, ARL15 in HCT116 showed statistical differences compared with the control group at 12 h, 24 h and 36 h (p<0.05). After adding 2 μM JIB-04, the protein expression levels of AKT, p-GSK, FASN, AMPK and SREBP-1 in HCT116 cells decreased significantly after 24 h. It was also found that the expression levels of AKT, P-GSK, FASN, AMPK and SREBP-1 genes in the dose-adding group were significantly lower than those in the control group. In summary, ARL15 may promote the occurrence of colon cancer by increasing the expression of protein kinase B/AMP-activated protein kinase (AKT/AMPK) downstream regulatory enzymes for glycogenesis and lipogenesis. JIB-04 can target ARL15 and affect its expression as well as the expressions of glucose and lipid metabolity-related proteins in AKT and AMPK signaling pathways.