PRKAA2 and neoplasm: Ex-4 inhibits mTOR, an autophagy inhibitor in tumor cells, by downregulating Akt and simultaneously activating AMPK, subsequently attenuating the phosphorylation of its major downstream targets, eukaryotic translation initiation factor 4e binding protein 1(4E-BP1) and ribosomal s6 kinase 1(S6K1).