The accumulation of angiostatin-like fragments in human prostate carcinoma

T. Migita, Y. Oda, S. Naito, W. Morikawa, M. Kuwano, M. Tsuneyoshi

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Abstract

Purpose: Angiostatin, a potent inhibitor of angiogenesis and, hence, the growth of tumor cell metastasis, is generated by a proteolytic enzyme from plasminogen. However, its localization and specific enzymes have yet to be ascertained in human tissue. Experimental Design: To elucidate the generation and the localization of angiostatin in prostate carcinoma, we examined angiostatin generation in a panel of human prostate cancer cell lines and performed immunohistochemistry with the antibodies to angiostatin and prostate-specific antigen (PSA), a potent proteolytic enzyme of angiostatin in 55 cases of prostate carcinoma. Results: We demonstrated that the lysates of human prostate carcinoma cell lines could generate angiostatin-like fragments from purified human plasminogen but could not generate angiostatin in the absence of exogenous plasminogen. The fragmented proteins were reacted with the monoclonal antibody specific for plasminogen lysine-binding site 1 (LBS-1). Immunohistochemically, the intracytoplasmic immunostaining of LBS-1 was positive in 87.3% (48 of 55) of prostate carcinoma cases, and the immunostaining of miniplasminogen was negative in all cases. There was a significant relationship between the positive immunostaining of LBS-1 and Gleason score (P = 0.0007). The intracytoplasmic immunostaining of PSA was positive in 37.0% (20 of 54) of prostate carcinoma cases, but there was no significant relationship between the expression of PSA and Gleason score, or between the positive immunostaining of LBS-1 and PSA. Conclusions: These findings suggest that angiostatin is generated by prostate carcinoma cells and is accumulated within the cytoplasm. In addition, the generation of angiostatin-like fragments was correlated with tumor grade; however, PSA may not be the only enzyme for angiostatin generation in human prostate carcinoma.

Original languageEnglish
Pages (from-to)2750-2756
Number of pages7
JournalClinical Cancer Research
Volume7
Issue number9
Publication statusPublished - Oct 10 2001

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All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research

Cite this

Migita, T., Oda, Y., Naito, S., Morikawa, W., Kuwano, M., & Tsuneyoshi, M. (2001). The accumulation of angiostatin-like fragments in human prostate carcinoma. Clinical Cancer Research, 7(9), 2750-2756.