Metabolic cooperation between co-cultured lung cancer cells and lung fibroblasts

Abstract

Cooperation of cancer cells with stromal cells, such as cancer-associated fibroblasts (CAFs), has been revealed as a mechanism sustaining cancer cell survival and growth. In the current study, we focus on the metabolic interactions of MRC5 lung fibroblasts with lung cancer cells (A549 and H1299) using co-culture experiments and studying changes of the metabolic protein expression profile and of their growth and migration abilities. Using western blotting, confocal microscopy and RT-PCR, we observed that in co-cultures MRC5 respond by upregulating pyruvate dehydrogenase (PDH) and the monocarboxylate transporter MCT1. In contrast, cancer cells increase the expression of glucose transporters (GLUT1), LDH5, PDH kinase and the levels of phosphorylated/inactivated pPDH. H1299 cells growing in the same culture medium with fibroblasts exhibit a 'metastasis-like' phenomenon by forming nests within the fibroblast area. LDH5 and pPDH were drastically upregulated in these nests. The growth rate of both MRC5 and cancer cells increased in co-cultures. Suppression of LDHA or PDK1 in cancer cells abrogates the stimulatory signal from cancer cells to fibroblasts. Incubation of MRC5 fibroblasts with lactate resulted in an increase of LDHB and of PDH expression. Silencing of PDH gene in fibroblasts, or silencing of PDK1 or LDHA gene in tumor cells, impedes cancer cell's migration ability. Overall, a metabolic cooperation between lung cancer cells and fibroblasts has been confirmed in the context of direct Warburg effect, thus the fibroblasts reinforce aerobic metabolism to support the intensified anaerobic glycolytic pathways exploited by cancer cells.

Subpopulation targeting of pyruvate dehydrogenase and GLUT1 decouples metabolic heterogeneity during collective cancer cell invasion

“…An ordinary one-way ANOVA with a Tukey's multiple comparisons test was used to determine significance compared to PLKO.1; shPDHA1 p = 0.0006, shPDHA1 with DCA p = 0.0007. diversification of metabolic dependencies could theoretically enable invading cells to better adapt to the selective pressures of the tumor microenvironment and maintain the ability to "go" and "grow" as a cooperative unit. While metabolic heterogeneity has been observed in solid tumors 66,67 and metabolic cooperation has been described between cancer cells and the stroma [68][69][70] , this is the first report of metabolic cooperation within the lung cancer collective invasion pack.…”

Metabolic reprogramming-based characterization of circulating tumor cells in prostate cancer

“…Previous research has found that overexpression of HK2 and PKM2 governs the glucose influx and sustain high levels of glycolysis to promote cancer cell migration and induce stem cell differentiation [ 28 , 29 ]. PDP2 is the activator of pyruvate dehydrogenase (PDH), and the function of PDH in the cancer-associated fibroblasts was demonstrated essential for the migration ability of the co-cultured cancer cells [ 30 ]. PHKA1 and PYGL are regulators of glycogen metabolism which balances the glucose supply.…”

Lactate Beyond a Waste Metabolite: Metabolic Affairs and Signaling in Malignancy

“…Interestingly, microRNA-containing exosomes secreted by CAFs were able to inhibit oxidative metabolism in cancer cells, while providing them with intact metabolites, namely glucose, to sustain their growth (95). In such an inverted scenario, CAFs oxidize cancer cell-derived lactate to support tumor proliferation (96); this has been correlated with resistance to targeted therapy (80). In addition to CAFs, the metabolic promiscuity described above involves other cells of the TME, namely immune and endothelial cells (Figure 1).…”