Management of
prostate cancer, especially advanced
prostate cancer, remains clinically challenging and requires the identification of new
biomarkers and therapeutic targets that can be exploited to improve patient outcome.
Galectin-3 (gal-3) is a
carbohydrate-binding protein involved in
cancer progression and
metastasis, including prostate tissues. Gal-3 function is regulated by proteolytic cleavage and the cleaved gal-3 is implicated in
tumor progression. This study is the first to determine gal-3 expressions with two monoclonal anti-gal-3
antibodies in prostate tissues to distinguish expression patterns between intact and cleaved gal-3 and analyze their clinical relevance. Our results showed gal-3 cleavage occurred in
prostate cancer but not normal prostate. Gal-3 presented in
tumor tissues was mainly the cleaved form that can be detected by the anti-gal-3 antibody targeting C terminal. The cleaved gal-3, but not the intact gal-3, was increased in
prostate cancer compared to normal prostate tissues and positively associated with malignance,
tumor progression and
metastasis. In addition, the expression of cleaved gal-3 was closely related to PSA level, indicating a PSA-mediated degradation of intact gal-3 in
prostate cancer. In summary, our findings suggested the cleaved gal-3 could be a valuable diagnostic
biomarker and a therapeutic target for the treatment of
prostate cancer, especially advanced metastatic
prostate cancer.