Effect in weeks one and two for cells grown in 1 and
Effect in weeks one and two for cells grown in 1 and 4.5 g/l of glucose. This trend disappeared at week three, and the level of cell proliferation was similar to that of the control. The effect of GR was more pronounced on the MCF-7 cell line. As shown in Figure 3b, reducing the glucose concentration in the media significantly decreased the cell proliferation over time. The proliferation of cells grown without glucose reduced by 30 from the first week (P = 0.057), and this reduction was enhanced at the second week, when only less than 40 of cells remained alive (P = 0.0001). The MCF-7 cell count was not extended into the third week because all of the cells grown in DMEM containing 0 g/L of glucose had died. Cells incubated in 1 g/L of glucose exhibited reduced proliferation by 20 at the second week (P = 0.0139). After 15 days, 2.5 M BIBR 1532 could reduce cell proliferation by 35 only when cells were incubated in physiological glucose concentrations (P = 0.0051).Regulation of mitochondrial metabolism by glucose restriction and BIBRWater-soluble tetrazolium salt WST-1 was used to assess the cell viability. This test reflects not only the cell viability but also the metabolism of mitochondria, as reported by several works [27,28]. Figure 4a shows that GR apparently decreased the succinate Pepstatin A web reductase activity in MDA-MB 231 cells by 55 and by more than 5-foldfor cells grown in 1 g/l and 0 g/l of glucose, respectively. In MCF-7 cells, GR reduced the mitochondrial activity by 35 PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/26080418 and by more than 80 in cells grown in 1 g/l and 0/gl glucose, respectively (P = 0.0009). This decrease was not caused by cell death because healthy quasiconfluent cells were detected in all wells using microscopic examination, bromophenol blue staining, and cell counts. This experiment was extended to evaluate the effect of BIBR 1532 in the GR conditions. As shown in Figure 5a, BIBR 1532 significantly reduced succinate reductase activity in MDA-MB 231 cells grown in 1 g/L and 4.5 g/L glucose. This effect was potentiated at a high glucose level (4.5 g/L), where 10 M BIBR 1532 could reduce WST-1 transformation by 35 . However, this effect was absent when cells were grown in 0 g/l glucose. As shown in Figure 5b, higher concentrations of BIBR 1532 are required to elicit the same effect observed in MDA-MB 231 cells. This telomerase inhibitor could reduce WST-1 transformation by 25 starting from 50 M, and this reduction became more significant when the BIBR 1532 concentration was increased to 100 M (P = 0.0011). A high concentration of BIBR 1532 (100 M) is required to inhibit the mitochondrial metabolism by 25 in cells incubated in 1 g/L of glucose (P = 0.029). This modulator effect was absent in cells grown without glucose. Telomerase-negative human osteosarcoma Saos-2 cells have previously been studied to examine the role of telomerase in mitochondrial metabolism modulation. TheWardi et al. Cancer Cell International 2014, 14:60 http://www.cancerci.com/content/14/1/Page 5 ofFigure 3 (See legend on next page.)Wardi et al. Cancer Cell International 2014, 14:60 http://www.cancerci.com/content/14/1/Page 6 of(See figure on previous page.) Figure 3 Effect of GR on the proliferation of MDA-MB 231 and MCF-7 BIBR 1532 treated cells. The cells were seeded at a very low density in a 25 cm2 flask and grown in DMEM culture medium containing 10 FBS and 1 Pen/Strep at different glucose concentrations with or without 2.5 M of BIBR 1532. The medium was replaced every two days,.