title: Blocking M2 muscarinic receptor signaling inhibits tumor growth and reverses epithelial-mesenchymal transition (EMT) in non-small cell lung cancer (NSCLC).
abstract: Lung cancers express non-neuronal, cholinergic autoparacrine loop, which facilitates tumor growth. Interruption of M3 muscarinic cholinergic signaling has been reported to inhibit small cell lung cancer (SCLC) growth. The purpose of this study is to investigate if blocking autoparacrine muscarinic cholinergic signaling could inhibit non-small cell lung cancer (NSCLC) growth and possible underlying mechanisms. Our results showed that PC9 and A549 cells expressed all 5 subtypes of muscarinic receptor (mAChR) and blocking M2 mAChR (M2R) signaling using selective antagonist methoctramine or short hairpin RNA (shRNA) inhibited tumor cell proliferation in vitro and in vivo. Consistent with AChR agonists stimulating p44/42 MAPK (Erk1/2) and Akt phosphorylation, blocking M2R signaling decreased MAPK and Akt phosphorylation, indicating that non-neuronal ACh functions as an autoparacrine growth factor signaling in part through activation of M2R and downstream MAPK and Akt pathways. Importantly, further studies revealed that blocking M2R signaling also reversed epithelial-mesenchymal transition (EMT) in vitro and in vivo, indicating that non-neuronal ACh promotes EMT partially through activation of M2R. These findings demonstrate that M2R plays a role in the growth and progression of NSCLC and suggest M2R antagonists may be an efficacious adjuvant therapy for NSCLC.
authors.affiliation: a Department of Pharmacology; Shanghai Jiao Tong University School of Medicine ; Shanghai , China.
authors.forename: Qingnan
authors.initials: Q
authors.lastname: Zhao
authors.forename: Xiajing
authors.initials: X
authors.lastname: Gu
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
authors.forename: Qin
authors.initials: Q
authors.lastname: Lu
authors.forename: Hongzhuan
authors.initials: H
authors.lastname: Chen
authors.forename: Lu
authors.initials: L
authors.lastname: Xu
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy* / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D003959:Diamines / Q000494:pharmacology; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D043585:Receptor, Muscarinic M2 / Q000037:antagonists & inhibitors*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D003959:Diamines; D043585:Receptor, Muscarinic M2; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D000109:Acetylcholine; C054938:methoctramine
keywords: ACh, acetylcholine; AChR, acetylcholine receptor; AKT; ChAT, choline acetyltransferase; EMT, epithelial-mesenchymal transition; M2 muscarinic receptor; M2R, M2 mAChR; MAPK ERK; MAPK, mitogen-activated protein kinase; NSCLC, non-small cell lung cancer; SCLC, small cell lung cancer; autoparacrine; epithelial-mesenchymal transition; mAChR, muscarinic receptor; nAChR, nicotinic receptor; non-neuronal acetylcholine; non-small cell lung cancer; shRNA, short hairpin RNA