Preliminary immunohistochemical characterization of a monoclonal antibody (pro:4-216) prepared from human prostate cancer nuclear matrix proteins - 10/09/11

Doi : 10.1016/S0090-4295(97)00337-3

Alan W. Partin ^⁎, Joseph V. Briggman, Eric N.P. Subong, Robert Szaro, Ana Oreper, Sarah Wiesbrock, Jane Meyer, Donald S. Coffey, Jonathan I. Epstein
From the Departments of Urology and Pathology, The Johns Hopkins University School of Medicine and the James Buchanan Brady Urological Institute, The Johns Hopkins Medical Institution, Baltimore, Maryland; and Matritech, Inc., Cambridge, Massachusetts, USA

^*Reprint requests: Alan W. Partin, M.D., Ph.D., The Department of Urology, The Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD 21287-2101.

Abstract

Objectives

A nuclear matrix protein (PC-1) was previously identified and reported to be present only in human prostate cancer but absent in tissue from the same prostate containing either benign prostatic hyperplasia (BPH) or normal prostate tissue. The PC-1 protein was identified by high resolution two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and exhibited a molecular mass of 56 kDa and an isoelectric point of 6.58. This work investigates the immunohistochemical characterization of PRO:4-216, a monoclonal antibody to PC-1.

Methods

Areas of the 2D-PAGE gels containing the human prostate cancer nuclear matrix proteins near PC-1 were isolated, eluted, and injected into mice to develop monoclonal antibodies. Antibodies were screened by immunofluorescence for nuclear reactivity to a human prostate cancer cell line (LnCaP) and by 1D and 2D Western blots for reactivity with prostate cancer nuclear matrix proteins. Monoclonal antibodies from the selected clones were affinity purified. The monoclonal antibody PRO:4-216 was used to analyze frozen tissue from 20 cancerous, 22 BPH, and 22 normal regions from fresh human prostate specimens. Tissue sections were analyzed for their immunohistochemical (IHC) (horseradish peroxidase) staining.

Results

Using a reference value for positive staining at an IHC score of greater than 50, 85% (17 of 20) of the cancerous, 5% (1 of 22) of the BPH, and 9% (2 of 22) of the normal prostate tissues stained positive. The one BPH and two normal tissues that stained positive were taken from prostates in which the adjacent cancerous tissue also demonstrated high IHC scores (greater than 225).

Conclusions

These data demonstrate nuclear reactivity on fresh frozen human prostate cancer tissue for the monoclonal antibody PRO:4-216. PRO:4-216 may aid in distinguishing normal prostate and BPH from cancerous tissue.

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*	This work was supported in part by NCI SPORE grant P50-CA 58236-03, NCI SBIR grant 1 R43 CA62 785-01, and by Matritech, Inc., Cambridge, Massachusetts.