Expression of prolactin and prolactin receptor in human breast carcinoma. Evidence for an autocrine/paracrine loop
Abstract
The neuroendocrine hormone prolactin is a growth factor required for the proliferation and terminal differentiation of the human breast.
These effects are mediated by the prolactin receptor, a member of the growth factor receptor family.
Three prolactin receptor isoforms (long, intermediate, and short) have been identified in the rat, which differ in the length of their intracytoplasmic domains. In humans, however, only the long prolactin receptor isoform had been identified previously. The expression of the human intermediate prolactin receptor is demonstrated and preliminary evidence for a human short isoform is presented.
Heterogeneous expression of prolactin receptor, at the immunoblot and immunohistochemical levels was observed in breast carcinoma specimens.
A statistically significant correlation between prolactin receptor and estrogen receptor expression was noted.
An autocrine/paracrine role for prolactin within breast tissues was further examined by performing reverse transcription polymerase chain reaction on RNA isolated from cell lines and clinical specimens with prolactin-specific primers. A 585-bp product was observed and found to be identical to human prolactin.
The synthesis of prolactin by breast epithelium was confirmed by in situ hybridization analysis of breast tissues and the detection of bio- and immunoreactive prolactin in breast cancer lines.
These analyses indicate that the principal site for prolactin expression within the normal or malignant breast residues within the epithelium.
These data indicate that prolactin may participate in an autocrine/paracrine stimulatory loop within breast tissues and suggest a role for this growth factor in the pathogenesis of breast cancer.
See also:
- Official Web Site: The Di Bella Method;
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- Somatostatin in oncology, the overlooked evidences - In vitro, review and in vivo publications;
- Publication, 2018 Jul: Over-Expression of GH/GHR in Breast Cancer and Oncosuppressor Role of Somatostatin as a Physiological Inhibitor (from Di Bella's Foundation);
- Publication, 2019 Aug: The Entrapment of Somatostatin in a Lipid Formulation: Retarded Release and Free Radical Reactivity (from Di Bella's Foundation);
- Publication, 2019 Sep: Effects of Somatostatin and Vitamin C on the Fatty Acid Profile of Breast Cancer Cell Membranes (from Di Bella's Foundation);
- Publication, 2019 Sep: Effects of somatostatin, curcumin, and quercetin on the fatty acid profile of breast cancer cell membranes (from Di Bella's Foundation);
- Publication, 2020 Sep: Two neuroendocrine G protein-coupled receptor molecules, somatostatin and melatonin: Physiology of signal transduction and therapeutic perspectives (from Di Bella's Foundation);
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