A Novel Biomarker for Staging Human Prostate Adenocarcinoma: Overexpression of Matriptase with Concomitant Loss of its Inhibitor, Hepatocyte Growth Factor Activator Inhibitor-1 Mohammad Saleem, 1 Vaqar Mustafa Adhami, 1 Weixiong Zhong, 2 B. Jack Longley, 1 Chen-Yong Lin, 4 Robert B. Dickson, 4 Shannon Reagan-Shaw, 1 David F. Jarrard, 3 and Hasan Mukhtar 1 Departments of 1 Dermatology, 2 Pathology and Laboratory Medicine, and 3 Surgery, University of Wisconsin, Madison, Wisconsin; and 4 Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC Abstract Background: Matriptase, a type II transmembrane serine protease is involved in angiogenesis, degradation of extra- cellular matrix, and in the progression of some epithelial cancers. Here, we establish the clinical significance of matriptase and its inhibitor, hepatocyte growth factor activator inhibitor-1 (HAI-1), during the progression of human prostate cancer (CaP). Methods: The expression patterns of matriptase and HAI-1 were determined in primary cultures of normal human prostate epithelial (NHPE) cells, human CaP cells LNCaP, DU-145, CWR22RN1, and PC-3, and in tissue samples of 172 patients with normal prostate, benign prostatic hyperplasia (BPH), prostatic intraepithelial neoplasia (PIN), and adeno- carcinoma of different tumor grades. Results: The protein and mRNA levels of matriptase were significantly higher in all carcinoma cells as compared with NHPE cells. Conversely, all CaP cells exhibited a reduced expression of HAI-1 as compared with NHPE cells. A progressive increase in the protein levels of matriptase was observed with increasing tumor grade in CaP specimens as compared with normal and BPH tissue specimens. Tissue samples of normal prostate exhibited a high constitutive protein level of HAI-1 compared with BPH and low-grade cancer with a progressive loss with increasing tumor grade. Conclusion: The increased expression of matriptase and loss of HAI-1 may be an important event during the progression of CaP in humans. We suggest that the ratio of these two gene products may serve as a promising biomarker for CaP progression and a potential marker for establishing the efficacy of therapeutic and chemopreventive interventions. (Cancer Epidemiol Biomarkers Prev 2006;15(2):217 – 27) Introduction Prostate cancer (CaP) is the most common visceral cancer diagnosed in men; it is the second leading cause of cancer- related deaths in males in the U.S. and in the Western world (1). The lack of effective therapies for advanced CaP reflects, to a large extent, the paucity of knowledge about the molecular pathways involved in CaP development. Thus, the identification of new predictive biomarkers will be important for improving clinical management, leading to improved survival of patients with CaP. Such molecular targets, especially those that are indicative of invasiveness of the disease, will also be excellent candidate targets for staging the disease and establishing the effectiveness of therapeutic and chemopreventive intervention of CaP (2, 3). Among the critical pathologic processes that occur during the progression and metastasis of CaP is the breakdown of extracellular matrix (ECM) and interstitial stroma (4). An array of ECM-degrading proteases have been identified and implicated in cancer invasion and metastasis (5). The serine proteases with conserved residues of histidine, aspartate, and serine constitute a novel family of transmembrane enzymes involved in numerous biological processes, including activa- tion of growth and angiogenic factors, and in the degradation of ECM components (6). The high expression of serine and other proteases in CaP are reported to be correlated with poor survival of the patients (7, 8). Because of a high level of serine protease expression in several human solid tumors, these enzymes have recently been proposed as potential diagnostic, prognostic, and/or therapeutic targets for several human tumors (9). Matriptase, a type II transmembrane protein also known as tumor-associated differentially expressed gene-15 (TADG-15), is a serine protease and has been detected in various tissues of epithelial origin along with many cell lines in vitro and has been characterized as an activator of tumor cell invasion and metastases (10, 11). Matriptase has been shown to be overex- pressed during tumor growth, invasion, and progression of breast, cervical, and ovarian cancer of humans (12-18). Virtually nothing is known about the function of matriptase in the prostate, with the exception of a study that identified a serine protease, MT-SP1, identical to matriptase in the prostatic cell line PC-3 (19). In addition, a recent study has shown that the specific inhibition of matriptase in CaP cells inhibits tumorigenesis in an athymic nude mouse model (20). The hepatocyte growth factor activator inhibitor-1 (HAI-1), a Kunitz-type serine protease inhibitor found predominantly in the columnar epithelium of many tissue types including breast, stomach, lung, kidney, prostate, and uterus, has been shown to modulate the activity of matriptase in several cancer types (10, 12, 21-24). HAI-1 has been shown to suppress the growth and motility of carcinoma cells by inhibiting the matriptase activity (12, 13). In the current study, we provide evidence for the first time for overexpression of matriptase with concomitant loss of HAI- 1 in human CaP cells and tissue specimens and show that this 217 Cancer Epidemiol Biomarkers Prev 2006;15(2). February 2006 Received 9/26/05; revised 11/14/05; accepted 12/19/05. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Requests for reprints: Hasan Mukhtar, Department of Dermatology, University of Wisconsin, 1300 University Avenue, Medical Sciences Center, B-25, Madison, WI, 53706. Phone: 608-263- 3927; Fax: 608-263-5223. E-mail: hmukhtar@wisc.edu Copyright D 2006 American Association for Cancer Research. doi:10.1158/1055-9965.EPI-05-0737 Downloaded from http://aacrjournals.org/cebp/article-pdf/15/2/217/2264941/217.pdf by guest on 13 June 2022