fig5

Figure 5. GPR81 is required for cancer cell proliferation and cancer cell survival when lactate is the primary fuel source. A: viable cell counts of MCF-7-siNT (control) and MCF-7-siGPR81 after 72 and 96 h of transfection and subtracting the initial cell number; B: real-time qPCR analysis of proliferation markers: Ki67, Cyclin B1, PCNA and STK15; C: Western blot analysis of cell lysates from MCF-7-siNT and MCF-7-siGPR81 cells after 72 and 96 h of transfection used to detect protein expression levels of the apoptotic maker cleaved-PARP. β-actin was used as a loading control; D: MCF-7-siNT and MCF-7-siGPR81 breast cancer cells were cultured in 3-dimensional Matrigel with physiological modified medium containing only lactate at 0.1 mmol/L, 1 mmol/L and 10 mmol/L concentration for 96 h; E: MCF-7 breast cancer cells were cultured in 3-dimensional Matrigel with physiological modified medium containing only lactate at 0.1 mmol/L, 1 mmol/L and 10 mmol/L concentration and treated with or without MCT1 inhibitor SR 13800 for 96 h. Viable cell counts after treatment. Results are presented as mean ± S.E.M. of three independent experiments; *P < 0.05; **P < 0.01; ***P < 0.001 (ordinary one-way ANOVA)