Fig. 6

Mammary epithelial cell metabolic changes and response to lactate depletion on the hydrogels. a, b NMR spectroscopy data of major metabolite changes in the culture media of HUMEC or MM231 cells grown on the three types of hydrogels for 7 days. HRMAS spectra, blue = decoupled proton spectra; red = ¹³C-¹H coupled spectra. c–h Effect of lactate depletion from the culture medium on the proliferation of HUMEC or the different subtypes of breast cancer cells grown on Matrigel. Error bars represent mean ± SD of three independent experiments, with each experiment having triplicate samples. There were no significant differences in the proliferation of the HUMEC cells cultured on the different gels. MM231 cells: *P < 0.05 for 0.05 U/ml versus 0.2 or 0.8 U/ml (t = 18.172 and t = 19.492) and 0.05 U/ml versus no LOX (t = 15.280), respectively, and **P < 0.001 for 0.2 U/ml and 0.8 U/ml versus no LOX (t = 30.454 and t = 26.801). There was no significant difference between the 0.2 U/ml and 0.8 U/ml groups; MM468 cells: *P < 0.05 for 0.05 U/ml versus 0.2 and 0.8 U/ml (t = 7.268 and t = 4.577), **P < 0.001 for no LOX versus 0.05, 0.2, and 0.8 U/ml (t = 6.865, t = 8.387, and t = 9.639); T47D cells: *P < 0.05 for no LOX versus 0.05, 0.2, and 0.8 U/ml (t = 26.869, t = 6.242, and t = 3.380). There was no significant difference between the 0.05, 0.2, and 0.8 U/ml groups; BT474 cells: *P < 0.05 for 0.8 U/ml versus 0.05 and 0.2 U/ml (t = 6.038 and t = 5.201), **P < 0.001 for 0.05, 0.2, and 0.8 U/ml versus no LOX (t = 7.388, t = 9.115, and t = 12.747). There was no significant difference between the 0.05 U/ml and 0.2 U/ml groups; SKBR3 cells: *P < 0.05 or **P < 0.001, comparing all concentrations of LOX except for between 0.05 U/ml and 0.2 U/ml, which had no significant difference (no LOX vs. 0.05, 0.2, and 0.8 U/ml, t = 3.807, t = 2.817, and t = 7.523, respectively; 0.8 U/ml vs. 0.05 and 0.2 U/ml, t = 2.655 and t = 3.7587)