ABSTRACT
Biologically active kinin peptides are released from precursor kininogens by kallikreins. Kinins act on kinin receptors to mediate diverse biological functions including smooth muscle contraction, inflammation, pain and mitogenicity. All components of the kallikrein-kinin system exist in human male genital secretions suggesting that these molecules participate in physiological and pathophysiological genitourinary function. The objective of this study was to assess the consequences of kinin action on prostate cells. Primary cultures of prostate secretory epithelial (PE) and prostate fibromuscular stromal (PS) cells were established from human prostate tissue. Transcripts encoding both the human B1 and B2 bradykinin receptor subtypes were detected in human prostate transition-zone tissue and in cultured cells by RT-PCR. In receptor binding assays, the B1 subtype predominated on PE cell membranes and the B2 subtype predominated on PS cell membranes. In PS cells, but not in PE cells, BK induced significant inositol phosphate accumulation and [3H]-thymidine uptake. These responses were mediated through the B2 receptor subtype. The use of signal transduction inhibitors indicated that mitogenic activation by BK occurred through both protein kinase C (PKC) and protein tyrosine kinase dependent mechanisms. PMA (phorbol 12-myristate 13-acetate) produced maximal [3H]-thymidine uptake by PS cells, resulted in cell elongation and caused the alpha-actin fibres present in PS smooth muscle cells to became organized into parallel arrays along the length of the elongated cells. In summary, the prostate contains a functional kallikrein-kinin system, which could be significant in physiological and pathophysiological prostate function.
Subject(s)
Bradykinin/physiology , Mitogens/physiology , Muscle Fibers, Skeletal/physiology , Prostate/cytology , Stromal Cells/drug effects , Bradykinin/metabolism , Bradykinin/pharmacology , Fluorescent Antibody Technique , Humans , Hydrolysis , In Vitro Techniques , Kallidin/metabolism , Kinins/metabolism , Male , Microscopy, Fluorescence , Muscle Fibers, Skeletal/drug effects , Phorbol Esters/pharmacology , Phosphatidylinositols/metabolism , Prostate/drug effects , Receptors, Bradykinin/biosynthesis , Signal Transduction/drug effects , Signal Transduction/physiology , Thymidine/metabolismABSTRACT
Despite the well-characterized histology associated with benign prostatic hyperplasia, very little is known about the underlying etiology of the disease on a molecular basis. The objective of this study was to use the technique of mRNA differential display in order to identify genes differentially expressed in human transition zone prostate tissue with high stromal density, with high epithelial density, and with nonhyperplastic histology. The extracellular matrix chondroitin/dermatan sulfate proteoglycan (CDSP) mRNA was more abundantly expressed in tissue with high stromal density, consistent with earlier findings that dermatan and chondroitin 6-sulfate glycosaminoglycans are increased in hyperplastic prostates. Messenger RNA encoding the negative regulator of cell cycle progression, BTG2, was more abundantly expressed in tissue with high epithelial densities. CDSP mRNA was abundantly expressed in primary cultures of stromal cells but was undetectable in epithelial cells. BTG2 mRNA was expressed in primary cultures of both cell types, but more abundantly in epithelial cells. BTG2 mRNA, but not CDSP mRNA, was subject to significant growth cycle regulation in cultured stromal and epithelial cells, with maximum expression occurring in quiescent cells. Generation of specific antibodies to BTG2 revealed that this protein was expressed at low levels in stroma, nonhyperplastic glands, and in hyperplastic glands. Consistent with a role in cell-cycle regulation, BTG2 protein was abundantly expressed in atrophic glands and preatrophic glands.
Subject(s)
Cell Cycle Proteins/genetics , Chondroitin Sulfate Proteoglycans/genetics , Dermatan Sulfate/genetics , Genes, Tumor Suppressor , Immediate-Early Proteins/genetics , Prostatic Hyperplasia/genetics , Atrophy , Base Sequence , Cell Division , Cells, Cultured , DNA, Complementary , Epithelial Cells , Gene Expression Regulation , Humans , Male , Molecular Sequence Data , Polymerase Chain Reaction/methods , Prostate/pathology , Prostatic Hyperplasia/pathology , RNA, Messenger , Stromal Cells , Tumor Suppressor ProteinsABSTRACT
OBJECTIVES: To determine whether repeat biopsy is necessary when the diagnosis of high-grade prostatic intraepithelial neoplasia (HGPIN) is made with a 12-core biopsy. Repeated biopsy has been recommended for individuals with HGPIN noted on sextant prostate biopsy because of the high likelihood of cancer detection. Recently, we have recommended the routine use of 12 cores, rather than 6, to improve cancer detection. METHODS: The charts of all patients undergoing prostate biopsy during a 2-year period at the Manhattan Veterans Administration Medical Center were reviewed. Patients diagnosed with HGPIN on a 12-core biopsy were identified, and those undergoing a repeat 12-core biopsy within 1 year of the initial biopsy were evaluated to determine the rate of cancer detection. RESULTS: A total of 619 men underwent biopsy during the study period. Of 103 men diagnosed with HGPIN, 43 underwent a repeat biopsy within 1 year at the discretion of the managing urologist. The mean age and median prostate-specific antigen level of those undergoing a repeat biopsy was 65.5 years and 5.37 ng/mL, respectively. At the time of the repeat biopsy, 1 patient was found to have cancer (2.3%), 20 had HGPIN (46.5%), 20 had benign pathologic findings (46.5%), and 1 patient (2.3%) had atypical small acinar proliferation. CONCLUSIONS: A repeat biopsy after the diagnosis of HGPIN on 12-core prostate biopsy rarely results in cancer detection. In the absence of other factors increasing the suspicion of cancer, immediate repeat biopsy for HGPIN diagnosed on a 12-core biopsy is unnecessary.