Changes in prolactin receptor location in prostate tumors

Area of Science:

• Oncology
• Cell Biology
• Endocrinology

Background:

• Prolactin (PRL) signaling through its receptor (PRLR) influences prostate cancer (PCa) cell proliferation, differentiation, and survival via STAT5a, MAPK, and AKT pathways.
• Understanding the expression patterns of PRL and PRLR in normal and cancerous prostate tissues is crucial for elucidating PCa pathogenesis.

Purpose of the Study:

• To investigate the expression levels and localization of Prolactin (PRL) and Prolactin Receptor (PRLR) in normal prostate tissues and prostate cancer (PCa) with varying Gleason patterns.
• To explore the potential autocrine and paracrine roles of PRL/PRLR signaling in prostate cancer.

Main Methods:

• Immunohistochemistry was employed to evaluate the intensity, location, and percentage of PRL and PRLR staining in normal, benign prostatic hyperplasia, and PCa tissues.
• Confocal microscopy was utilized to assess the co-localization of PRL and PRLR within prostate epithelial cells.
• Samples were obtained from radical prostatectomy specimens, representing a range of Gleason patterns.

Main Results:

• PRL expression was observed in the cytoplasm of normal and tumor prostate luminal cells, with increased expression noted in Gleason pattern 3.
• PRLR expression levels and the percentage of positive cells did not significantly differ between normal and tumor tissues.
• PRLR localization shifted from the plasma membrane in normal tissues to intracellular vesicles in tumor tissues, with demonstrated co-localization of PRL and PRLR.

Conclusions:

• Both PRL and PRLR are present in the cytoplasm of prostate epithelial cells in both normal and cancerous glands.
• The altered intracellular localization of PRLR in tumor tissues suggests a mechanism for maintaining active signaling pathways involved in prostate cancer cell proliferation and survival.