Alpha2 macroglobulin, a PSA binding protein, is expressed in human prostate stroma

Victor K. Lin, Shih Ya Wang, Nicholas C. Boetticher, Dolores V. Vazquez, Hossein Saboorian, John D. McConnell, Claus Roehrborn

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


BACKGROUND. Benign prostatic hyperplasia (BPH) is characterized as a stromal process. The stroma smooth muscle (SM) may alter its phenotype during the progression of BPH. We have identified gene transcripts that may be differentially expressed in BPH using a differential display method. Among the fragments isolated, α2 macroglobulin (α2-M) is one of the most interesting. α2-M is a binding protein of a variety of proteinases, including prostatic specific antigen (PSA). It also plays roles in molecular trapping and targeting. In this study, we characterized α2-M expression in the human prostate. METHODS. Differential display was used to identify and isolate the differentially expressed transcripts between normal prostate and BPH tissues. RT-PCR, Western blot, in situ hybridization, and immunohistochemistry were utilized to confirm and characterize α2-M expression in the prostate. RESULTS. Real-time RT-PCR results revealed that a 3.2-fold increase in α2-M mRNA expression is observed in BPH compared with normal prostate tissue. A 1.9-fold increase at protein level was also observed. In situ hybridization and immunohistochemistry showed that α2-M expression is primarily localized to the stromal compartment. Cultured primary stroma cells maintained α2-M expression, while prostate epithelial cells had a significantly lower level of α2-M expression. Furthermore, stromal cells in culture produce and secrete α2-M in the medium. CONCLUSIONS. We identified α2-M expression in the human prostate. An increased α2-M expression appears to be associated with BPH. Considering the unique features of its protein binding and targeting properties, α2-M expressed in the prostate may play an important role in regulating benign and malignant prostatic growth.

Original languageEnglish (US)
Pages (from-to)299-308
Number of pages10
Issue number3
StatePublished - May 15 2005


  • Alpha macroglobulin
  • Benign prostatic hyperplasia
  • Differential display
  • RT-PCR

ASJC Scopus subject areas

  • Oncology
  • Urology


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