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Updated: Jul 29, 2026

Microarray-based Identification of Individual HERV Loci Expression: Application to Biomarker Discovery in Prostate Cancer
Published on: November 2, 2013
PAR, a novel androgen regulated gene, ubiquitously expressed in normal and malignant cells
1Department of Medicine, Health Science Center at Brooklyn, SUNY and VA Medical Center, Brooklyn, NY 11209, USA.
Abstract:
During our work on the mechanism of hormone resistance of prostatic carcinomas, a novel gene that we called PAR (prostate androgen regulated) was isolated from an androgen resistant subline (LNCaP-OM) using a modified representational difference analysis. The complete sequence of the gene cDNA has 1029 nucleotides with a continuous reading frame of 438 bases encoding for 146 amino acids. Its deduced amino acid sequence has motifs for myristoylation and phosphorylation by protein kinase C. The PAR gene was overexpressed in all prostatic carcinoma cell lines studied (LNCaP, DU145, PC3 and LNCaP-OM) compared to the normal prostatic tissue. Furthermore, its expression was higher in androgen resistant prostate cancer lines DU145, PC3 and LNCaP-OM, in comparison to androgen sensitive LNCaP cells. The expression of this gene was down regulated by androgens in androgen sensitive prostate cells, but not in the hormone resistant cell lines. The PAR mRNA was detected in all 29 normal human tissues studied and overexpressed in most (67%) of their malignant counterparts. The PAR expression was higher in MCF7 and T47D breast cancer cell lines, as well as in all primary breast tumors studied compared to their normal tissue counterparts. The biological function of this gene is still unknown, but its ubiquitous expression in normal tissues and its overexpression in some malignancies suggest the PAR involvement in certain basic cellular processes and possibly, in malignant transformation.
Insights
A novel gene, prostate androgen regulated (PAR), is overexpressed in prostate and breast cancers, particularly in hormone-resistant forms. Its expression is linked to malignancy and may play a role in cancer development.
Area of Science:
- Molecular Biology
- Oncology
- Genetics
Background:
- Hormone resistance in prostate cancer is a significant clinical challenge.
- Understanding the genetic mechanisms underlying hormone resistance is crucial for developing new therapies.
Purpose of the Study:
- To identify and characterize novel genes involved in prostate cancer, particularly those related to androgen resistance.
- To investigate the expression patterns of the identified gene in various cancer types and normal tissues.
Main Methods:
- Modified representational difference analysis for gene isolation.
- cDNA sequencing and amino acid sequence analysis.
- Quantitative analysis of gene expression in cell lines and human tissues using mRNA detection.
Main Results:
- A novel gene, prostate androgen regulated (PAR), was identified.
- PAR gene is overexpressed in prostate carcinoma cell lines compared to normal tissue.
- PAR expression is higher in hormone-resistant prostate cancer cells and is not downregulated by androgens.
- PAR mRNA is detected in normal tissues and overexpressed in most malignant counterparts, including breast cancer.
Conclusions:
- The PAR gene is consistently overexpressed in various cancers, suggesting a potential role in tumorigenesis.
- Its differential regulation by androgens in resistant vs. sensitive prostate cancer cells highlights its involvement in hormone resistance.
- The ubiquitous expression in normal tissues and overexpression in malignancies indicate PAR's involvement in fundamental cellular processes and potentially malignant transformation.
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