Investigation of the oxytocin receptor expression in human breast cancer tissue using newly established monoclonal antibodies.

Abstract

The expression of the oxytocin (OT) receptor (OTR) in breast cancer was studied using newly established anti-OTR monoclonal antibodies. Immunoblotting indicated that the antibody 2F8 recognized a 70K OTR in the pregnant myometrium and breast cancer tissue. Among 57 breast cancer patients, we detected OTR immunoreactivity in 52 (91.2%) by immunohistochemistry using 2F8. Using another monoclonal antibody for different receptor domains, 1-2, the staining profile was identical in all positive samples. Of 52 OTR-positive samples, 28 were diffusely positive (> 80% of cancer cells were stained), and 24 were partially positive (< 80% cells were stained). The ratio of estrogen receptor-positive samples was slightly higher among those that were diffusely positive, but there was no apparent relationship between OTR expression and other clinical parameters. We also confirmed the expression of the OTR in positively stained samples by means of Northern blotting and RT-PCR at the transcription level. The OTR messenger RNA and RT-PCR product were the same size as those in the pregnant myometrium. We also determined the expression of the OTR using flow cytometry in four breast cancer cell lines (MCF-7, MDA-MB-231, MDA-MB-361, and MDA-MB-468). However, OT had no significant effect on their growth during a short period (7 days) of culture. These findings indicated that the OTR is expressed in breast cancer derived not from the myoepithelium but from the glandular or ductal epithelium; however, the biological function of OT in breast cancer remains to be determined.

Oxytocin receptor pattern of expression in primary lung cancer and in normal human lung

“…In breast cancer, in vitro effects of OT on cell proliferation vary from antiproliferative to mitogenic (26,28,47,48). In choriocarcinoma, OT promotes cell growth (30), whereas it decreases proliferation of glial tumors, endometrial adenocarcinomas, and neuroblastomas (23,27).…”

Oxytocin receptor gene expression in rat mammary gland: structural characterization and regulation

“…A longitudinally cut mammary gland milk duct is shown in the central part of each panel. studies using specific antibodies against the human uterine-type OTR provided evidence of presence of immunologically identical receptor molecules in the human mammary gland (Bussolati et al 1996, Ito et al 1996, Sappino et al 1998. Although the present and previous studies indicate that the uterine-type OTR gene is expressed in mammary gland, the existence of an additional, very different OTR subtype that is sufficiently different to remain unrecognized by the different probes used here cannot be totally excluded.…”

Iodide transport and breast cancer

“…This discrepancy could be due to a variety of technical considerations (Arturi et al 2005). The oxytocin receptor is present in 50-90% of breast cancers (Bussolati et al 1996, Ito et al 1996, Sapino et al 1998 and is a G protein-coupled receptor capable of activating the G s -cAMP-protein kinase A (PKA) pathway (Olins & Bremel 1984) (Fig. 2).…”