Nonneuronal Cholinergic System in Breast Tumors and Dendritic Cells: Does It Improve or Worsen the Response to Tumor?
Figure 2
Expression and function of muscarinic acetylcholine receptors (mAChR) in breast tumor cells. Carbachol (Carb) stimulates mAChR and via Gq/11 protein increases phospholipase C (PLC) activity. This enzyme hydrolyzes phosphoinositides producing myoinositol 1,4,5-trisphosphate (IP3) and increases intracellular calcium levels which in turn activates nitric oxide synthase (NOS) that produces nitric oxide (NO). mAChRs also couple to Gi protein and inhibit the activation of adenilyl cyclase (AC) reducing cAMP formation. The agonist also increases synthesis and liberation of vascular endothelial growth factor-A (VEGF-A) and metalloproteinase-9 expression and activity in tumor cell supernatants.
