BRIEF REPORT |
Correspondence to: Anthony G. DiLella, Dept. of Pharmacology, Merck Research Laboratories, P.O. Box 4, West Point, PA 19486. Email: tony_dilella@merck.com
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Summary |
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Differences between benign prostatic hyperplasia (BPH) and normal prostate tissue at the level of mRNA expression provide an opportunity to identify candidate genes for this disease. A cDNA subtraction procedure was used to isolate differentially expressed genes in BPH. The subtraction was done by solution hybridization of BPH cDNA against excess normal prostate cDNA. We identified known, EST, and novel genes by sequence and database analysis of the subtracted cDNAs. Several of these cDNAs were used as probes in Northern blotting analysis to confirm over-expression of their corresponding mRNAs in BPH tissues. One highly upregulated sequence of interest shared identity with a known mRNA encoding human NELL2, a protein containing epidermal growth factor-like domains. NELL2 was not previously reported to be expressed in prostate and may code for a novel prostatic growth factor. In situ hybridization analysis of hyperplastic prostate specimens demonstrated that NELL2 mRNA expression is predominantly localized in basal cells of the epithelium. Disease-related changes in the levels of NELL2 may contribute to alterations in epithelialstromal homeostasis in BPH. (J Histochem Cytochem 49:669670, 2001)
Key Words: benign prostatic hyperplasia, mRNA, cDNA subtraction, Northern blotting, in situ hybridization
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Introduction |
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Benign prostatic hyperplasia (BPH) is an age-related disease, and most men over 50 years of age have urinary tract symptoms arising from this disorder. The cellular and molecular processes involved in the development and pathogenesis of BPH are not well understood. The objective of this study was to identify differentially expressed genes involved in the uncontrolled prostate growth that characterizes BPH.Prostate tissue was obtained after written consent from each patient and was approved by the local ethics committee. mRNA isolated from BPH and normal prostate mRNA was subjected to a subtractive and kinetic enrichment procedure (
Before subtraction, cDNA populations from normal and BPH tissue were indistinguishable (Fig 1A, Lanes 1 and 2, respectively). By an iterative process of subtractive and kinetic enrichment, cDNA fragments that were upregulated in BPH were selected (Fig 1A, Lane 3). Sequence and database analysis of these fragments identified at least 15 known, EST, and novel genes. Five clones were hybridized to Northern blots to verify expression patterns. Fig 1B shows the detection of highly upregulated mRNA in BPH (clones 1 and 3) in addition to mRNA specific for BPH (clones 2, 4, and 5) compared to normal prostate.
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Sequences representative of clones 1 and 3 were further analyzed and revealed identity to lactoferrin and NELL2, respectively. Lactoferrin is an iron-binding glycoprotein expressed in inflamed prostate (
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Footnotes |
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Presented in part at the Joint Meeting of the Histochemical Society and the International Society for Analytical and Molecular Morphology, Santa Fe, NM, February 27, 2001.
Received for publication December 6, 2000; accepted February 16, 2001.
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Literature Cited |
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