Peptides binding to prostate-specific antigen enhance its antiangiogenic activity

Area of Science:

• Oncology
• Biochemistry

Background:

• Prostate-specific antigen (PSA), also known as kallikrein-related peptidase 3 (KLK3), exhibits antiangiogenic properties.
• Elevated PSA levels in prostate tumors may impede cancer progression by inhibiting angiogenesis.
• This study explores stimulating PSA activity to reduce prostate tumor growth.

Purpose of the Study:

• To investigate whether peptides C4 and B2, which stimulate PSA enzymatic activity, can enhance PSA's antiangiogenic effects.
• To determine if stimulating PSA activity can be a strategy to inhibit prostate tumor growth.

Main Methods:

• An in vitro angiogenesis assay using human umbilical vein endothelial cells (HUVECs) cultured on Matrigel was employed.
• The effect of proteolytically active PSA and PSA-stimulating peptides (C4, B2) on endothelial cell tube formation was quantified.
• An angiogenesis index was used to measure the extent of tube formation.

Main Results:

• PSA alone reduced the angiogenesis index by approximately 50% compared to controls.
• The addition of peptides C4 or B2 with PSA further decreased the angiogenesis index by about 70% compared to PSA alone.
• Increasing PSA concentration 2.4-fold with peptides yielded a similar reduction in the angiogenesis index.

Conclusions:

• Stimulating PSA activity with specific peptides significantly enhances its inhibitory effect on endothelial cell tube formation.
• This finding supports the hypothesis that enhancing PSA activity can be a viable strategy to reduce angiogenesis and inhibit prostate tumor progression.