PMID- 22406476 OWN - NLM STAT- MEDLINE DCOM- 20120807 LR - 20220409 IS - 1528-0012 (Electronic) IS - 0016-5085 (Print) IS - 0016-5085 (Linking) VI - 142 IP - 7 DP - 2012 Jun TI - Aspirin inhibits mTOR signaling, activates AMP-activated protein kinase, and induces autophagy in colorectal cancer cells. PG - 1504-15.e3 LID - 10.1053/j.gastro.2012.02.050 [doi] AB - BACKGROUND & AIMS: Aspirin reduces the incidence of and mortality from colorectal cancer (CRC) by unknown mechanisms. Cancer cells have defects in signaling via the mechanistic target of rapamycin (mTOR), which regulates proliferation. We investigated whether aspirin affects adenosine monophosphate-activated protein kinase (AMPK) and mTOR signaling in CRC cells. METHODS: The effects of aspirin on mTOR signaling, the ribosomal protein S6, S6 kinase 1 (S6K1), and eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1) were examined in CRC cells by immunoblotting. Phosphorylation of AMPK was measured; the effects of loss of AMPKalpha on the aspirin-induced effects of mTOR were determined using small interfering RNA (siRNA) in CRC cells and in AMPK(alpha1/alpha2-/-) mouse embryonic fibroblasts. LC3 and ULK1 were used as markers of autophagy. We analyzed rectal mucosa samples from patients given 600 mg aspirin, once daily for 1 week. RESULTS: Aspirin reduced mTOR signaling in CRC cells by inhibiting the mTOR effectors S6K1 and 4E-BP1. Aspirin changed nucleotide ratios and activated AMPK in CRC cells. mTOR was still inhibited by aspirin in CRC cells after siRNA knockdown of AMPKalpha, indicating AMPK-dependent and AMPK-independent mechanisms of aspirin-induced inhibition of mTOR. Aspirin induced autophagy, a feature of mTOR inhibition. Aspirin and metformin (an activator of AMPK) increased inhibition of mTOR and Akt, as well as autophagy in CRC cells. Rectal mucosal samples from patients given aspirin had reduced phosphorylation of S6K1 and S6. CONCLUSIONS: Aspirin is an inhibitor of mTOR and an activator of AMPK, targeting regulators of intracellular energy homeostasis and metabolism. These could contribute to its protective effects against development of CRC. CI - Copyright (c) 2012 AGA Institute. Published by Elsevier Inc. All rights reserved. FAU - Din, Farhat V N AU - Din FV AD - Colon Cancer Genetics Group and Academic Coloproctology, Institute of Genetics and Molecular Medicine, University of Edinburgh and Medical Research Council Human Genetics Unit, Western General Hospital Edinburgh, United Kingdom. Farhat.Din@igmm.ed.ac.uk FAU - Valanciute, Asta AU - Valanciute A FAU - Houde, Vanessa P AU - Houde VP FAU - Zibrova, Daria AU - Zibrova D FAU - Green, Kevin A AU - Green KA FAU - Sakamoto, Kei AU - Sakamoto K FAU - Alessi, Dario R AU - Alessi DR FAU - Dunlop, Malcolm G AU - Dunlop MG LA - eng GR - 12076/CRUK_/Cancer Research UK/United Kingdom GR - MC_U127088492/MRC_/Medical Research Council/United Kingdom GR - MC_U127527198/MRC_/Medical Research Council/United Kingdom GR - C26031/A11378/CRUK_/Cancer Research UK/United Kingdom GR - U.1270(60416)/MRC_/Medical Research Council/United Kingdom GR - 11378/CRUK_/Cancer Research UK/United Kingdom GR - MC_U127015387/MRC_/Medical Research Council/United Kingdom GR - U.1270(70193)/MRC_/Medical Research Council/United Kingdom PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20120306 PL - United States TA - Gastroenterology JT - Gastroenterology JID - 0374630 RN - 0 (Adaptor Proteins, Signal Transducing) RN - 0 (Anti-Inflammatory Agents, Non-Steroidal) RN - 0 (CRTC2 protein, human) RN - 0 (Cell Cycle Proteins) RN - 0 (EIF4EBP1 protein, human) RN - 0 (Phosphoproteins) RN - 0 (Ribosomal Protein S6) RN - 0 (Transcription Factors) RN - DD5K7529CE (Phenformin) RN - EC 2.7.11.1 (Ribosomal Protein S6 Kinases, 70-kDa) RN - EC 2.7.11.1 (TOR Serine-Threonine Kinases) RN - EC 2.7.11.1 (ribosomal protein S6 kinase, 70kD, polypeptide 1) RN - EC 2.7.11.31 (AMP-Activated Protein Kinases) RN - R16CO5Y76E (Aspirin) SB - IM MH - AMP-Activated Protein Kinases/drug effects/*metabolism MH - Adaptor Proteins, Signal Transducing/metabolism MH - Animals MH - Anti-Inflammatory Agents, Non-Steroidal/*pharmacology MH - Aspirin/*pharmacology MH - Autophagy/*drug effects MH - Cell Cycle Proteins MH - Cell Line, Tumor MH - Colorectal Neoplasms/*metabolism MH - Female MH - Humans MH - Intestinal Mucosa/metabolism MH - Mice MH - Mice, Knockout MH - Phenformin/pharmacology MH - Phosphoproteins/metabolism MH - Phosphorylation/drug effects MH - Ribosomal Protein S6/metabolism MH - Ribosomal Protein S6 Kinases, 70-kDa/metabolism MH - Signal Transduction/*drug effects MH - TOR Serine-Threonine Kinases/antagonists & inhibitors/*metabolism MH - Transcription Factors/metabolism PMC - PMC3682211 MID - EMS52952 OID - NLM: EMS52952 EDAT- 2012/03/13 06:00 MHDA- 2012/08/08 06:00 PMCR- 2013/06/14 CRDT- 2012/03/13 06:00 PHST- 2011/06/13 00:00 [received] PHST- 2012/02/21 00:00 [revised] PHST- 2012/02/27 00:00 [accepted] PHST- 2012/03/13 06:00 [entrez] PHST- 2012/03/13 06:00 [pubmed] PHST- 2012/08/08 06:00 [medline] PHST- 2013/06/14 00:00 [pmc-release] AID - S0016-5085(12)00313-7 [pii] AID - 10.1053/j.gastro.2012.02.050 [doi] PST - ppublish SO - Gastroenterology. 2012 Jun;142(7):1504-15.e3. doi: 10.1053/j.gastro.2012.02.050. Epub 2012 Mar 6.