MTOR and neoplasm: Consistent with a role of AMPK activation in negative regulation of mTOR signaling30, Aspirin treatment also led to markedly reduced p4EBP1 and modestly reduced pS6RP levels, whereas combined use of Aspirin and GDC-0941 resulted in nearly diminished mTOR signaling (Fig. 6a).Together, these results suggested that Aspirin may suppress tumor growth by activation of AMPK and inhibition of mTOR signaling, but less likely by inhibiting COX-2.