Background: Fibromodulin is a small leucine-rich proteoglycan important for extracellular matrix organization and essential for tissue repair in multiple organs. The main function of this proteoglycan is the regulation of collagen fibrillogenesis; however, more recently described roles for fibromodulin have expanded to include regulation of angiogenesis, reprogramming of human fibroblasts into pluripotent cells, modulation of TGF-β activity, inflammatory processes and association with metastatic phenotypes. Additionally, fibromodulin has been identified as a novel tumor-associated antigen in leukemia, lymphoma, and leiomyoma. Knowledge about its expression in the prostate is limited.
Methods: Fibromodulin expression was analyzed in two different malignant and one non-tumorigenic prostatic cell lines in culture, and in benign and malignant human prostate tissue. Expression was analyzed by real time PCR, immunocytochemistry, and immunohistochemistry. DNA sequencing was performed on a PCR fragment amplified with primers specific for the FMOD gene from cDNA obtained from the cultured cell lines.
Results: Both immunostaining and real time PCR analysis of cell lines indicated that fibromodulin was differentially expressed in the cancerous cell lines compared to the non-tumorigenic cell line. Likewise, cancerous tissue expressed significantly higher levels of intracellular fibromodulin compared to matched, benign tissue from the same patients, as well as compared to tissue from patients with only benign disease.
Conclusions: The expression of fibromodulin was higher in prostatic cancer cells (cell-lines and human tissue) than in normal/benign prostatic cells. Additional studies are required to determine the biological and clinical significance and whether this proteoglycan has a role in carcinogenesis of the prostate or in prostate cancer related inflammatory processes.
Keywords: Fibromodulin; corpora amylacea; extracellular matrix; immunohistochemistry; inflammation; prostate cancer.