Glucose Metabolism In Fibroblasts Research Articles

Abstract LB039: Ovarian cancer cell-derived exosomal UCA1 reprograms glucose metabolism in stromal fibroblasts

Abstract Tumor progression is stringently regulated by the co-ordinated signaling between the tumor cells and the tumor microenvironment (TME) through diverse autocrine, paracrine and exocrine signaling mechanisms. Recent studies have shown that the exosomes that play a crucial role in the transfer of oncogenic macromolecules and oncometabolites to different cellular components of the TME can be targeted for therapy. Therefore, with the focus on identifying the exosomal long non-coding RNA (lncRNA) that can be therapeutically targeted, we investigated the profile of ovarian cancer cell derived lncRNAs and their functional role in ovarian cancer pathophysiology. Analysis of exosomes derived from a panel of high grade serous ovarian cancer cell lines indicated that UCA1 (Urothelial Cancer Associated 1) is the most abundantly packaged lncRNA in the exosomes. Similarly, exosomes from patient-derived ovarian cancer cells exhibited higher levels of UCA1. Ascites from ovarian cancer patients also indicated high levels of UCA1 in the ascites-derived exosomes. Results using PKH67-labelled ovarian cancer cell-derived exosomes and MRC5 fibroblast cell line indicated the exosomal transfer of UCA1 to the fibroblasts. Since paracrine signaling has been shown to induce metabolic reprogramming of peritumoral fibroblasts, we interrogated whether exosomal transfer of UCA1 could reprogram the glucose metabolism in the fibroblasts. Results from the Agilent Seahorse glycolytic stress assay indicate that the exosomal UCA1 promotes reprogramming of glucose metabolism in fibroblast cells while depleting of UCA1 in the exosomes failed to induce such metabolic reprogramming. Results from the analysis of the key glycolytic enzymes in the stromal fibroblasts, post-exosomal UCA1 uptake also corroborate this conclusion. Thus our results provide primary evidence that the exosomal-UCA1 induces pro-tumorigenic metabolic reprogramming in peri-tumoral fibroblasts. Together with the known oncogenic role of UCA1 in many different cancer cells, our findings indicate that targeting UCA1 could form a productive precision cancer strategy in ovarian cancer, targeting both the tumor cells and tumor stromal cells. This research was supported by the Department of Defense Ovarian Cancer Research Program Award W81XWH-18-1-0066, W81XWH-22-1-0415, the National Institute of General Medical Sciences grant P20 GM103639 and The National Cancer Institute of the National Institutes of Health grant P30 CA225520. Citation Format: Revathy Nadhan, Ji Hee Ha, Muralidharan Jayaraman, Srishti Kashyap, Danny N. Dhanasekaran. Ovarian cancer cell-derived exosomal UCA1 reprograms glucose metabolism in stromal fibroblasts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB039.

TRAP1 suppresses oral squamous cell carcinoma progression by reducing oxidative phosphorylation metabolism of Cancer-associated fibroblasts

BackgroundGlucose metabolism in cancer associated fibroblasts (CAFs) within the tumor microenvironment is a material and energy source for tumorigenesis and tumor development. However, the characteristics and important regulatory mechanisms of glucose metabolism in fibroblasts associated with oral squamous cell carcinoma (OSCC) are still unknown.MethodsWe successfully isolated, cultured, purified and identified CAFs and normal fibroblasts (NFs). Cell culture, immunohistochemistry (IHC) and CCK8, flow cytometry, Seahorse XF Analyzer, MitoTracker assay, western blotting (WB), transmission electron microscope, Quantitative real-time PCR (qPCR), immunofluorescence (IF), and Label-free quantitative proteomics assay, animal xenograft model studies and statistical analysis were applied in this study.ResultsWe demonstrated that the proliferation activity of CAFs was significantly enhanced as compared to NFs, while the apoptosis rate was significantly decreased. CAFs in OSCC preferentially use oxidative phosphorylation (OXPHOS) rather than glycolysis. Moreover, CAFs showed stronger maximal respiration, a larger substantial mitochondrial spare respiratory capacity (SRC) and higher adenosine triphosphate (ATP) production capacity than NFs. The results of mitotracker green fluorescence staining showed that compared with NFs, CAFs exhibited stronger green fluorescence. The results of WB showed the expression level of Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) obviously increased in CAFs compared to NFs. These results confirmed that CAFs have greater mitochondrial activity and function than NFs. Furthermore, Label-free quantitative proteomics assays showed that both ATP synthase subunit O (ATP5O) and tumor necrosis factor receptor-associated protein 1 (TRAP1) are important differentially expressed proteins in the mitochondria of CAFs/NFs. Overexpression of TRAP1 in CAFs increased basal oxygen consumption rate (OCR), maximal respiration, ATP production and SRC. In vivo, overexpression TRAP1 expression in CAFs suppress tumor growth.ConclusionTaken together, the results indicated that TRAP1 is an important regulatory molecule of CAFs glucose metabolism and promotes OSCC progression by regulating the OXPHOS of CAFs.

Type II diabetes and insulin resistance. Evidence of lack of inherent cellular defects in insulin sensitivity.

To determine if inherent cellular differences in insulin sensitivity account for the insulin resistance of non-insulin-dependent diabetes, the effect of insulin on several aspects of cell glucose metabolism was compared in fibroblasts from diabetics and matched nondiabetic controls. The response of total cell glucose metabolism to insulin was assessed by measurement of 14C-glucose uptake. Insulin stimulated cell glucose incorporation in nondiabetic cells up to twofold with half-maximal stimulation at approximately 3 X 10(-9) M insulin. This was similar to that observed in diabetic cells. Insulin stimulation of I glycogen synthase activity was also compared in the cells from diabetics and nondiabetics. Both groups demonstrated a threefold increase in %I activity in the presence of insulin with half-maximal stimulation at approximately 2 X 10(-9) M. There were no differences between diabetics and nondiabetics in either magnitude of response or insulin concentration for half-maximal stimulation. Finally, insulin stimulation of hexose transport was compared in the two cell types using 2-deoxyglucose. In both groups hexose transport was elevated approximately 40% over baseline in the fibroblast in the presence of insulin, with half-maximal stimulation at approximately 2 X 10(-9) M insulin. No differences were found in insulin action on glucose metabolism in fibroblasts form diabetics and nondiabetics; these results may indicate that there are no inherent differences in cell sensitivity to insulin's glucoregulatory action in non-insulin-dependent diabetics.