**3.8. Muscarinic acetylcholine receptors as pharmacological targets in breast cancer**

IgG purified from the serum of breast cancer patients mimics the effect of carbachol by activating muscarinic acetylcholine receptors in MCF-7 breast cancer cells [136]. Moreover, these autoantibodies purified from the serum of breast cancer patients regulate the MCF7 breast cancer cell migration and the MMP-9 activity, and these effects are reduced by atropine, 4-DAMP (M<sup>3</sup> receptor antagonist), and tropicamide (M<sup>4</sup> receptor antagonist) [137].

**Acknowledgements**

**Author details**

Adrian Dumitru1†

This work was supported by a grant of the Romanian Ministry of Research and Innovation, CCCDI—UEFISCDI, project number PN-III-P1—1.2-PCCDI-2017-0833/68/2018, within PNCDI III.

, Sanda Maria Cretoiu<sup>4</sup>

\*, Dragos Cretoiu4,5,

Alterations in Calcium Signaling Pathways in Breast Cancer

http://dx.doi.org/10.5772/intechopen.80811

181

, Daniela Oana Toader2,3†

1 Department of Pathology, Emergency University Hospital, Bucharest, Romania

Alessandrescu-Rusescu National Institute of Mother and Child Health, Bucharest, Romania

3 Division of Obstetrics and Gynecology and Neonatology, Carol Davila University of

4 Division of Cellular and Molecular Biology and Histology, Carol Davila University of

5 Materno-Fetal Assistance Excellence Unit, Alessandrescu-Rusescu National Institute of

7 Life, Environmental and Earth Sciences Division, Research Institute of the University of

[1] Bosetti C, Bertuccio P, Chatenoud L, Negri E, La Vecchia C, Levi F. Trends in mortality from urologic cancers in Europe, 1970-2008. European Urology. 2011;**60**(1):1-15

[2] Ramsay DT, Kent JC, Hartmann RA, Hartmann PE. Anatomy of the lactating human breast redefined with ultrasound imaging. Journal of Anatomy. 2005;**206**(6):525-534 [3] Tobon H, Salazar H. Ultrastructure of the human mammary gland. II. Postpartum lactogenesis. The Journal of Clinical Endocrinology and Metabolism. 1975;**40**(5):834-844

6 Department of Anatomy, Animal Physiology, and Biophysics, Faculty of Biology,

2 Department of Obstetrics and Gynecology, Polizu Clinical Hospital,

Nicolae Suciu2,3 and Beatrice Mihaela Radu6,7

Medicine and Pharmacy, Bucharest, Romania

Medicine and Pharmacy, Bucharest, Romania

Mother and Child Health, Bucharest, Romania

University of Bucharest, Bucharest, Romania

Bucharest (ICUB), Bucharest, Romania

These authors contributed equally.

†

**References**

\*Address all correspondence to: sanda@cretoiu.ro

Carbachol, an agonist of muscarinic acetylcholine receptors, acts on M<sup>1</sup> and M<sup>3</sup> receptors in the MCF7 breast tumor cells and potentiates tumor progression, by activating nitric oxide synthase via phospholipase C and protein kinase C signaling pathways [114]. Carbachol also elicits the mobilization of intracellular-free Ca2+ and induces the phosphorylation of MAPK/ ERK in MCF-7 human breast cancer cells, while pretreatment with wortmannin or LY294002 (selective inhibitors of phosphoinositide 3-kinase), with genistein (nonselective inhibitor of tyrosine kinases) or with PP2 (specific Src tyrosine kinase inhibitor), diminished the carbachol-induced MAPK/ERK phosphorylation [118].

Moreover, carbachol upregulates the vascular endothelial growth factor-A in MCF7 tumor cells and determines angiogenesis, while atropine reverts its effects [136]. Carbachol treatment (20 hours) increased the tumor cell death and its administration in subthreshold concentrations in conjunction with paclitaxel potentiates cell death [138, 139], while atropine reverts these combined effects [138]. Interestingly, the combined treatment with carbachol (low doses) and paclitaxel induced the death of breast tumor MCF-7 cells, via the increased activity of nitric oxide synthase 1 and 3, and the reduced activity of arginase II, but the drug combination was ineffective against the nontumorigenic epithelial MCF-10A cell line, due to the absence of muscarinic acetylcholine receptors [140].

Although several preclinical studies indicated the pharmacological potential of M<sup>3</sup> antagonists in inhibiting tumor growth (e.g., melanoma, pancreatic, breast, ovarian, prostate, and brain cancers), no clinical trials have been done [109].
