The Mechanisms Of CD147-mediated Glucose Metabolic Reprogramming In Overian Cancer Cells Via A P53-independent Manner

It has been widely recognized that deregulating cellular energetics is emerging as a characteristic hallmark of cancer cells and a key contributor to tumor development. Among the many adjustments of the metabolic pathways that are found in tumor cells, a key role is played by an enhanced aerobic glycolysis. Reprogramming of glucose metabolism is a hallmark in various tumor origins, and serves cancer cells in proliferation and survival through maintenance of biosynthesis and redox homeostasis. However, it is still not completely clear why such a less efficient metabolism is selected by proliferating cancer cells. A previous study illustrates that CD147 functions as an oncoprotein to promote cell proliferation by partial regulation of cellular glucose metabolism via a p53-dependent signaling pathway in human hepatocellular carcinoma cells. p53 dysfunction is one of the most common genetic alterations found in cancer, and p53 is mutated in ～60% of ovarian malignancies. However, it has not yet been determined whether CD147 is involved in reprogramming of glucose metabolism and whether CD147-mediated glucose metabolic reprogramming is p53-independent in ovarian cancer cells. Here, we aim to elucidate the effects of CD147 on glucose metabolism by using the p53-null ovarian cancer cell line SKOV3, thus to describe the different mechanisms of CD147 in the regulation of glucose metabolic reprogramming in ovarian cancer cells. This project is helpful for deeply investigating abnormal energy metabolism of ovarian cancer and possibly provide new drug targets and therapeutic strategy clues.Part Ⅰ CD147 promotes glycolysis in ovarian cancer cells via a p53-independent mannerTo determine whether CD147 regulate glucose metabolism in ovarian cancer cells, we transfected A2780(p53 wild-type) and SKOV3(p53 null) cells with negative control shRNA or CD147 shRNA. The results showed that glucose uptake, glycolysis rate and lactate production were significantly decreased, whereas oxygen consumption was strongly increased by CD147 knockdown in A2780 and SKOV3 cells. Futhermore, micro-PET/CT imaging demonstrated that silencing CD147 with shRNA led to weak 18F-FDG uptake compared to the control group in SKOV3 cells, suggesting that the inhibition of glucose uptake by CD147 konckdown may lead to tumor inhibition. In the in vivo assay, the smaller tumors were seen in mice injected with CD147-silenced cells, in contrast to shRNA-control group. Taken together, our results suggest that CD147 promotes reprogramming of glucose metabolism in EOC cells, suggesting that CD147 may be an important target in aerobic glycolysis pathway for developing novel anticancer agents.Part Ⅱ the mechanism underlying the regulatory role of CD147 on FOXM1 expression in ovarian cancer cellsTo determine whether CD147 can regulate the expression of FOXM1, negative control shRNA(shNC) and CD147 shRNA(shCD147) were transfected into A2780 and SKOV3 cells. Western blot assays showed that the protein levels of CD147, pAKT, pSTAT3 and FOXM1 were significantly decreased by CD147 knockdown in A2780 and SKOV3 cells. In line with our above results, quantitative real-time PCR analyses showed that CD147 and FOXM1 mRNA levels were significantly decreased by CD147 knockdown in A2780 and SKOV3 cells. To dissect whether CD147 regulates FOXM1 through the AKT and STAT3 pathways, we examined FOXM1 expression after inhibition of the AKT pathway using LY294002 and the STAT3 pathway using S3I-201. Our results showed that CD147 transfection significantly upregulated the expressions of FOXM1, pAKT and pSTAT3, but this effect was reversed by LY294002 or S3I-201 treatment. The immunofluorescence staining results showed that there was a significant colocalization of CD147 with CD44 in ovarian cancer cells. Importantly, we further demonstrate that CD147, pAKT, pSTAT3 and FOXM1 were concomitantly overexpressed in ovarian cancer tissues.Part Ⅲ the mechanism underlying FOXM1-mediated glucose metabolic reprogramming in ovarian cancer cellsWe examined the effect of FOXM1 knockdown on the expression of a number of key genes involved in glycolysis, including GLUT1, GLUT4, HK2, LDHA, and so on. Quantitative real-time PCR and western blot analyses showed that GLUT1 and HK2 expression levels were significantly decreased by FOXM1 knockdown in A2780 and SKOV3 cells. Aerobic glycolysis and cell proliferation were down-regulated in ovarian cancer cells when FOXM1 gene expression was suppressed by RNA interference. Moreover, our data showed that FOXM1 bound directly to the GLUT1 and HK2 promoter regions and regulated the promoter activities and the expression of the genes at the transcriptional level. Importantly, we further demonstrate that the expression levels of FOXM1, GLUT1 and HK2 are significantly increased in human ovarian cancer tissues relative to normal ovarian tissues, and that FOXM1 expression is positively correlated with GLUT1 and HK2 expression.