ABSTRACT
Caveolin-1 (Cav-1), a major structural protein of caveolae, is implicated in the vesicular uptake processes of transcytosis and cell signaling. However, its role in modulating protein glycosylation and tumor metastasis remains to be further elucidated. In the present study, it was shown that Cav-1 promotes the expression of O-GlcNAcylation and O-GlcNAc transferase (OGT), and triggers the invasion and metastasis of hepatocellular carcinoma (HCC) cells. The results of RT-qPCR, Western blot and dual lucif-erase reporter assay showed that Cav-1 negatively regulated the expression of transcription factor RUNX2 in HCC. Subsequently, this results in attenuate RUNX2-induced transcription of miR24. miR24 suppresses mouse HCC cells invasion and metastasis via directly targeting Ogt mRNA 3′UTR. This research provides evidence of Cav-1-mediated OGT expression and O-GlcNAc (O-linked N-acetylglucosamine) elevation. These data give insight into a novel mechanism of HCC occurrence and development.
ABSTRACT
Objective By analyzing mitochondrial function, reactive oxygen species (ROS) and adenosine triphosphate (ATP) production under different levels of RalA and caveolin-1 (Cav-1) expression, to investigate the regulation role of RalA played in cancer metabolism and explore the possibility of its regulation role involved in Cav-1 and caveolae motility. Methods Firstly, RalA and Cav-1 expression were inhibited by siRNA in breast cancer cell line MDA-MB-231, and then the changes of mitochondrial membrane potential (MMP), ROS production, ATP generation and L-lactate level before and after inhibition were assessed by Western blotting, confocal microscope and fluorescence quantification. Results (1) The decreased RalA and Cav-1 expression led to a significant reduction of MMP directly. (2) Low RalA and Cav-1 expression resulted in an inhibition of ATP production and an increase of H2O2 generation. With the reduction of MMP, mitochondrial malfunction was observed. (3) With mitochondrial function suppression, an elevated level of glycolysis metabolite L-lactate was also detected in RalA and Cav-1 deprived cells. Conclusions RalA and Cav-1 mediate cellular metabolic switch by inhibiting mitochondrial function and simultaneously boosting glycolysis. This regulation role of RalA depends on its association with Cav-1, and possibly is related to the endocytosis and motility of caveolae. The research findings enrich the cancer metabolic studies, and provide a novel approach for cancer therapeutic strategy targeted to cellular metabolism.
ABSTRACT
Objective By analyzing mitochondrial function,reactive oxygen species (ROS) and adenosine triphosphate (ATP) production under different levels of RalA and caveolin-1 (Cav-1) expression,to investigate the regulation role of RalA played in cancer metabolism and explore the possibility of its regulation role involved in Cav-1 and caveolae motility.Methods Firstly,RalA and Cav-1 expression were inhibited by siRNA in breast cancer cell line MDA-MB-231,and then the changes of mitochondrial membrane potential (MMP),ROS produc tion,ATP generation and L-lactate level before and after inhibition were assessed by Western blotting,confocal microscope and fluorescence quantification.Results (1) The decreased RalA and Cav-1 expression led to a significant reduction of MMP directly.(2) Low RalA and Cav-1 expression resulted in an inhibition of ATP production and an increase of H2O2 generation.With the reduction of MMP,mitochondrial malfunction was observed.(3) With mitochondrial function suppression,an elevated level of glycolysis metabolite L-lactate was also detected in RalA and Cav-1 deprived cells.Conclusions RalA and Cav-1 mediate cellular metabolic switch by inhibiting mitochondrial function and simultaneously boosting glycolysis.This regulation role of RalA depends on its association with Cav-1,and possibly is related to the endocytosis and motility of caveolae.The research findings enrich the cancer metabolic studies,and provide a novel approach for cancer therapeutic strategy targeted to cellular metabolism.