title: Oxytocin does not induce a rise in intracellular free calcium in human breast cancer cells.
abstract: Research suggests that oxytocin acts as a growth modulating agent for breast cancer cells. However, the signaling mechanisms responsible for these modulatory effects have not been fully elucidated. In the physiological setting oxytocin is known to stimulate contraction of myometrial cells in the uterus and myoepithelial cells in the breast by increasing intracellular free calcium ([Ca2+]i). The expression of oxytocin receptor mRNA in T-47D breast cancer cells, and four additional breast cancer cell lines (BT-549, MCF-7, MDA-MB- 231, ZR-75-1), was confirmed by RT-PCR analysis. Oxytocin-induced changes in [Ca2+]i in indo-1 AM loaded T-47D breast cancer cells were monitored using flow cytometric analysis. In this cell line, oxytocin (0, 1, 10, 100, and 1,000 nM) did not induce a dose-dependent increase in the mean 405 nm/485 nm emission ratio. These results indicate that oxytocin signaling in T-47D breast cancer cells does not appear to involve an increase in [Ca2+]i.
authors.affiliation: Department of Pharmacology, Midwestern University, Downers Grove, IL 60515, USA. mfayxx@midwestern.edu
authors.forename: M J
authors.initials: MJ
authors.lastname: Fay
authors.forename: J
authors.initials: J
authors.lastname: Du
authors.forename: K A
authors.initials: KA
authors.lastname: Longo
authors.forename: W G
authors.initials: WG
authors.lastname: North
mesh_terms: D001483:Base Sequence; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002118:Calcium / Q000378:metabolism*; D017931:DNA Primers; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D006801:Humans; D010121:Oxytocin / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D018045:Receptors, Oxytocin / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D018045:Receptors, Oxytocin; D010121:Oxytocin; D002118:Calcium