...two thyroid cancer cells, OCUT1 and K1, both of which harbored PIK3CA mutation...when combined with MK2206, the temsirolimus-induced Akt activation was completely suppressed (Fig. 5B). Thus, the novel Akt inhibitor MK2206 could completely overcome the activating feedback of mTOR inhibition on Akt, demonstrating its potential utility in combination therapy with temsirolimus for thyroid cancer...Combination of the two drugs markedly potentiated the inhibitory effect of each other on cell proliferation (Fig. 5C, upper panel). Using the Chou-Talalay method, we calculated the CI and isobologram to further examine the interactions between the two inhibitors...all the CI values, at different combinations of the indicated concentrations of the two inhibitors, were less than 1 in the two cell lines, with virtually all the points less than 0.5. These CI values suggest a strong synergism between the two inhibitors...