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Updated: Aug 12, 2026
MicroRNA Detection in Prostate Tumors by Quantitative Real-time PCR (qPCR)
Published on: May 16, 2012
Molecular characterization of the loss of p75(NTR) expression in human prostate tumor cells
1Department of Cell Biology, Georgetown University Medical Center, Washington, DC, USA.
Abstract:
The low-affinity nerve growth factor receptor p75(NTR) is a 75-kDa glycoprotein that belongs to the tumor necrosis factor receptor superfamily and has been implicated in the induction of apoptosis in various tissues and cell lines. Immunohistochemistry on tissue sections from radical prostatectomies has shown that expression of p75(NTR) is limited to the epithelial cells. Western blot and immunohistochemical analyses have also shown a progressive loss of p75(NTR) expression in prostate epithelial cells during the malignant progression of organ-confined adenocarcinomas, with complete loss of expression in the naturally occurring prostate tumor cell lines DU-145, PC-3, LNCaP, and TSU-pr1, which were derived from metastases. Reintroduction of p75(NTR) expression into the TSU-pr1 tumor cell line was shown to reestablish the ability of these cells to undergo p75(NTR)-mediated apoptosis. It is not known whether this loss of expression is due to deletion of part or the entire p75(NTR) gene or to other factors. Through the use of southern blotting and polymerase chain reaction (PCR), we showed that loss of p75(NTR) protein expression was not due to deletion or loss of the gene. Furthermore, through reverse transcription-PCR, RNase protection, and the chromatin immunoprecipitation assay, we showed that transcription of the p75(NTR) gene occurred in these prostate tumor cell lines. Finally, through transient transfection using two constructs of p75(NTR), one containing the full 2-kb 3' untranslated region and one that contains only a few hundred bases of the 3' untranslated region (UTR), we showed that the 3' UTR may have a role in the loss of p75(NTR) expression in prostate cancer.
Insights
Prostate cancer cells lose the nerve growth factor receptor p75(NTR), which is crucial for apoptosis. This loss is not due to gene deletion but may involve the 3' untranslated region (UTR) affecting expression.
Area of Science:
- Molecular Biology
- Cancer Research
- Cell Biology
Background:
- The low-affinity nerve growth factor receptor p75(NTR) is a 75-kDa glycoprotein in the tumor necrosis factor receptor superfamily.
- p75(NTR) is implicated in apoptosis induction across various tissues and cell lines.
- p75(NTR) expression is normally limited to prostate epithelial cells.
Purpose of the Study:
- To investigate the mechanisms behind the loss of p75(NTR) expression during prostate cancer progression.
- To determine if gene deletion or other factors contribute to reduced p75(NTR) levels in prostate tumor cells.
Main Methods:
- Immunohistochemistry and Western blot analysis to assess p75(NTR) expression.
- Southern blotting and Polymerase Chain Reaction (PCR) to detect gene deletions.
- Reverse transcription-PCR, RNase protection, and chromatin immunoprecipitation assays to analyze gene transcription.
- Transient transfection assays using p75(NTR) constructs with varying 3' untranslated regions (UTR).
Main Results:
- Prostate epithelial cells show a progressive loss of p75(NTR) expression during malignant progression.
- Prostate tumor cell lines derived from metastases completely lack p75(NTR) expression.
- Loss of p75(NTR) protein expression is not caused by deletion or loss of the p75(NTR) gene.
- p75(NTR) gene transcription occurs in prostate tumor cell lines.
- The 3' UTR of p75(NTR) may play a role in the downregulation of its expression in prostate cancer.
Conclusions:
- The loss of p75(NTR) in prostate cancer is not due to genetic deletion.
- Gene transcription is active, suggesting post-transcriptional regulation is involved.
- The 3' UTR of p75(NTR) is a potential regulatory element contributing to its reduced expression in prostate cancer cells.
