Fig. 8

Targeting MAPK improves therapeutic response in 3D culture. 3D cultures of BT474 (a) and MDAMB361 (b) cells were treated for 10 days with trastuzumab and endocrine treatments as shown ± MEK inhibitor (U0126) or AKT inhibitor (MK-2206) and cell growth evaluated by coulter counting. Further samples were analysed for MAPK and AKT activity (c, d) by Western blotting. Inhibition of MEK significantly improved trastuzumab and endocrine response in MDMB361 and BT474 cells respectively. In both cell types, MEK inhibition but not AKT inhibition resulted in an augmentation of treatment-induced MAPK activity suppression (c, d; no data is shown for AKT in MDAMB361 cells as AKT activity was not detectable in cells in 3D culture). AKT inhibition did not improve growth suppression alone or in conjunction with trastuzumab or endocrine agent. C = control, H = trastuzumab (Herceptin), T = tamoxifen, F = fulvestrant. *p < 0.05 vs. no inhibitor