Decrease and Gain of Gene Expression Are Equally Discriminatory Markers for Prostate Carcinoma

Abstract

Information on over- and underexpressed genes in prostate cancer in comparison to adjacent normal tissue was sought by DNA microarray analysis. Approximately 12,600 mRNA sequences were analyzed from a total of 26 tissue samples (17 untreated prostate cancers, 9 normal adjacent to prostate cancer tissues) obtained by prostatectomy. Hierarchical clustering was performed. Expression levels of 63 genes were found significantly (at least 2.5-fold) increased, whereas expression of 153 genes was decreased (at least 2.5-fold) in prostate cancer versus adjacent normal tissue. In addition to previously described genes such as hepsin, overexpression of several genes was found that has not drawn attention before, such as the genes encoding the specific granule protein (SGP28), alpha-methyl-acyl-CoA racemase, low density lipoprotein (LDL)-phospholipase A2, and the anti-apoptotic gene PYCR1. The radiosensitivity gene ATDC and the genes encoding the DNA-binding protein inhibitor ID1 and the phospholipase inhibitor uteroglobin were significantly down-regulated in the cancer samples. DNA microarray data for eight genes were confirmed quantitatively in five normal and five cancer tissues by real-time reverse transcriptase-polymerase chain reaction with a high correlation between the two methods. Laser capture microdissection of epithelial and stromal compartments from cancer and histological normal specimens followed by an amplification protocol for low levels of RNA (<0.1 microg) allowed us to distinguish between gene expression profiles characteristic of epithelial cells and those typical of stroma. Most of the genes identified in the nonmicrodissected tumor material as up-regulated were indeed overexpressed in cancerous epithelium rather than in the stromal compartment. We conclude that development of prostate cancer is associated with down-regulation as well as up-regulation of genes that show complex differential regulation in epithelia and stroma. Some of the gene expression alterations identified in this study may prove useful in the development of novel diagnostic and therapeutic strategies.

Cysteine-rich secretory protein 3 overexpression is linked to a subset of PTEN-deleted ERG fusion-positive prostate cancers with early biochemical recurrence

“…Ernst et al, 3 described CRISP3 to be overexpressed 420-fold in microdissected prostate cancer as compared with adjacent normal prostate epithelium. Others found a 20-2000-fold upregulation of CRISP3 mRNA in cancerous prostate.…”

“…CRISP3 is expressed at low levels in normal human prostate and strongly upregulated in a fraction of prostate cancers. [3][4][5][6] The clinical relevance of CRISP3 overexpression is controversially discussed. Some studies found CRISP3 overexpression to be associated with increased risk of tumor recurrence, 7 unfavorable tumor phenotype, 8,9 castration-resistant prostate cancer, and metastasis, 9,10 whereas others could not find any clinically relevant associations.…”

Control of neuronal branching by the death receptor CD95 (Fas/Apo-1)

“…In all, 1 mg of total RNA was reverse transcribed essentially as described. 44,45 Biotin-labeling during in vitro transcription from the T7 promoter using the ENZO RNA Transcript labeling kit was performed according to the Affymetrix protocol. cRNA samples were hybridized on Mouse Genome U74Av2 chips (MG-U74Av2), and data analyzed using the Affymetrix MAS 5.0 software package.…”

Repuncturing the Renal Biopsy

“…Modifications of the initial protocol have resulted in considerable improvements of the linearity of the assay (64). Comparing the expression profiles generated before and after linear amplification, a high degree of reproducibility between identical samples analyzed in duplicate could be shown (correlation coefficient, 0.98) (66). This protocol enabled a com-prehensive expression profiling in microdissected samples, identifying comparable populations of regulated mRNAs in amplified and unamplified prostate tissue.…”

“…This protocol enabled a com-prehensive expression profiling in microdissected samples, identifying comparable populations of regulated mRNAs in amplified and unamplified prostate tissue. Confirmation of relevant mRNAs still should be performed by independent techniques, i.e., real-time RT-PCR (66).…”