Taken together with the RNAi data (Fig. 5B, C), these results indicate that in high p-AKT SCLC cells, the dual inhibition of PI3K and mTOR can induce cell death, accompanied by CASP6- and CASP3-mediated proteolytic cleavage of mTOR companion proteins. Here, CASP3 is linked to small cell lung carcinoma.