Figure 1. Sensitivity of breast cancer cell lines to Akt inhibition correlates with SGK1 mRNA levels.

(A) A panel of 21 breast cancer cell lines were screened in a standard 72 h MTS cell proliferation assay. Cell lines with a GI₅₀ value of <3 μM were classified as sensitive (open diamonds), cell lines with a GI₅₀ value of >3 μM were classified as resistant (closed diamonds) and cell lines with a sensitivity between the two were classified as intermediately sensitive (grey diamonds). SGK1 gene expression from whole transcriptome analysis (Affymetrix U133) was scaled relative to the expression range across a panel of 500 cell lines where 0=minimum and 1=maximum. (B) The indicated cells were exposed to increasing concentrations (0–10 μM) of MK-2206 or AZD5363 for 72 h and cell viability was determined using the MTS assay. Data were fitted to sigmoidal dose–response curves and GI₅₀ values and 95% confidence intervals (CI) were calculated using GraphPad Prism 5.0. Similar results were observed in two independent experiments. Where GI₅₀ values exceeded 20 μM, data were found to fit poorly to sigmoidal dose–response curves, and therefore no exact GI₅₀ values or 95% CIs are stated for these samples.