Autoantibodies from breast cancer patients regulate adhesion in MCF-7 human breast adenocarcinoma cells byactivation of muscarinic acetylcholine receptors

PELEGRINA LT; FISZMAN G,; LOMBARDI G,; AZAR ME,; CRESTA MORGADO C,; SALES ME

Buenos Aires

Congreso; First French Argentine Immunology Congress; 2010

Sociedad Argentina de Inmunologia-Sociedad Francesa de Inmunologia

Muscarinic acetylcholine receptors (mAChR) are expressed in human breast tumor tissue and in MCF-7 cells, a human mammary adenocarcinoma cell line, while they are absent in normal mammary cells, MCF-10A. We described the presence of antimAChR antibodies (Abs) in the sera of breast cancer patients in stage 1 (T1N0Mx: tumor diameter<2cm, without lymph node w.transbiomedicine.com metastasis). We have demonstrated that the muscarinic agonist carbachol (CARB) stimulated tumor cell proliferation and migration. Metastases are the first cause of death in cancer and it occurs when cells lose adhesion and migrate to distant organs. The aim of this work is to investigate the role of mAChR activation by CARB or T1NoMx-Abs on MCF-7 cells adhesion in an in vitro assay. We demonstrated that CARB inhibited tumor cell adhesion in a concentration dependent-manner, being 10-10M the maximal effective concentration (25.6 } 0.97 %; p<0.001 vs. basal). Pre-incubation of cells with atropine (AT: 10-9M) a non selective muscarinic antagonist, 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP: 10-9M) a selective antagonist for mAChR3 or tropicamide (TROP: 10-9M) a selective antagonist mAChR4, reverted the inhibition produced by CARB. In addition we observed that T1N0Mx-Abs from 5 patients with breast cancer mimicked the action of CARB producing a concentrationdependent inhibition in MCF-7 cells adhesion, being 10-8M the maximal effective concentration. The inhibition produced by T1N0Mx-Abs ranged from 16.71}3.4 % to 40.19}8.8 % (p<0.001 vs. basal). These effects were always reverted with AT and TROP but 4-DAMP was only effective to reduce Abs action in 3 of 5 patientes. CARB or Abs did not modify MCF-10A cells adhesion. IgG from normal patients or with mammary benign fribroadenoma, did not modify MCF-7 cells adhesion. We can conclude that anti-mAChR Abs present in breast cancer patients’ sera at early stages by stimulating migration and inhibiting adhesion could be promoting breast cancer metastases.