oxytocin and Cell-Transformation--Neoplastic

Breast cancer is making up one-quarter of all new female cancer cases diagnosed worldwide. Breast cancer surgeries, radiation therapies, cytotoxic chemotherapies and targeted therapies have made significant progress and play a dominant role in breast cancer patient management. However, many challenges remain, including resistance to systemic therapies, tumour recurrence and metastasis. The cyclic neuropeptide oxytocin (OT) elicits a plethora of biological responses via the oxytocin receptor (OTR) in both the central and peripheral nervous system, including social bonding, stress, maternal behaviour, sexual activity, uterus contraction, milk ejection and cancer. As a typical member of the G protein-coupled receptor family, OTR represents also an intriguing target for cancer therapy. There is emerging evidence that OTR plays a role in breast cancer development and progression, and several breast cancer cell lines express OTR. However, despite supporting evidence that OT lowers breast cancer risks, its mechanistic role in breast cancer development and the related signalling pathways are not fully understood. Here, we review the current knowledge of the OT/OTR signalling system in healthy breast tissue as well as in breast cancer, and discuss OTR as a potential therapeutic target for breast cancer management.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Cell Transformation, Neoplastic; Chemoprevention; Disease Management; Disease Models, Animal; Disease Susceptibility; Drug Evaluation, Preclinical; Female; Gene Expression Regulation, Neoplastic; Humans; Ligands; Molecular Targeted Therapy; Oxytocin; Receptors, Estrogen; Receptors, Oxytocin; Signal Transduction

Hypothalamic cells taken from 14-day-old mouse embryos were cultured for 6 days and transformed with simian virus 40. After cloning, a homogeneous cell population was obtained. Its morphological, Ultrastructural, biochemical, and immunochemical properties were studied. These cells possess ultrastructural features of primitive neurosecretory cells. They synthesize (35)S-labeled protein components that have the molecular weight and isoelectric focusing behavior of, and display the same immunoreactivity as, neurophysin. In addition, a (35)S-labeled peptidic fraction with a molecular weight close to 1000 is synthesized and is radioimmunologically indistinguishable from vasopressin. Immunochemical staining shows that both neurophysin and vasopressin are localized in the cytoplasm. These observations strongly suggest that a clone of mouse hypothalamic neurosecretory cells has been obtained with the synthesizing capacities of secretory neurons of the magnocellular hypothalamic nuclei.

Topics: Animals; Antigens, Viral; Cell Line; Cell Transformation, Neoplastic; Chromatography, Gel; Clone Cells; Cricetinae; Cytoplasm; Fluorescent Antibody Technique; Hypothalamus; Isoelectric Focusing; Mice; Molecular Weight; Neurophysins; Neurosecretion; Oxytocin; Rabbits; Radioimmunoassay; Simian virus 40; Sulfur Radioisotopes; Vasopressins