Kallikrein-3 (PSA) (PSA)

Kallikrein-3, widely known as Prostate-Specific Antigen (PSA), is a serine protease primarily synthesized by the secretory epithelial cells of the prostate gland. Its primary biological function is the liquefaction of the seminal coagulum by cleaving semenogelins, thereby facilitating sperm motility. PSA is a critical biomarker in clinical oncology, where elevated serum levels are used to screen for, diagnose, and monitor the progression of prostate cancer and benign prostatic hyperplasia. In therapeutic development, PSA serves as a tumor-associated antigen for various immunotherapies, including mRNA-based vaccines like CV9103 and viral-vector vaccines like PROSTVAC, which aim to stimulate a cytotoxic T-cell response against malignant cells. Furthermore, the specific proteolytic activity of PSA is utilized in prodrug strategies, where inactive toxins are engineered to be selectively activated by the enzyme within the tumor microenvironment. Despite its utility, targeting PSA or using it for screening presents challenges such as overdiagnosis and the potential for treatment-related side effects like urinary incontinence.

Other names

Prostate-specific antigenKLK3P-30 antigenGamma-seminoproteinSemininhK3Kallikrein-related peptidase 3

Induction of antigen-specific T-cell immune response; Enzymatic activation of prodrugs; Protease inhibition