Expression, Purification, and Characterization of Deglycosylated Human Pro-Prostate-Specific Antigen

Prostate‐specific antigen (PSA) protein does not affect growth of prostate cancer cells in vitro or prostate cancer xenografts in vivo

“…These studies also point out the importance of determining enzymatic activity of PSA-transfected cells prior to use in assays assessing effects of PSA on growth, invasion, or metastasis. To date, no group, including ours, has successfully produced a mammalian cell line that makes significant quantities of enzymatically active PSA [12,13,15,20]. In reports where mammalian cells are used for PSA transfection, the PSA produced by the cell lines appears to be proPSA because typically a second protease such as hK2 or trypsin must be added to produce enzymatically active PSA [11][12][13].…”

“…Recombinant PSA has been expressed in a number of non-prostate cell types including mammalian cells, yeast, and insect cells using the baculovirus system. Bowman et al expressed PSA in Chinese Hamster Ovary (CHO) cells in order to study glycosylation patterns and collected pro-PSA that was then activated by trypsin [15]. Similarly, Kumar et al used Syrian Hamster cells (AV-12) and generated pro-PSA that could be activated by addition of exogenous hK2 [13].…”

“…Previously, we demonstrated that only $20% of the PSA produced by LNCaP cells in vitro is enzymatically active [7,19]. Other groups have demonstrated that this PSA from LNCaP cells is inactive due to incorrect, that is, underprocessing of the PSA propeptide sequence [14,15]. Therefore, we set out to develop a better model to test our prodrug constructs.…”

Effects of Glycosylation on the Enzymatic Activity and Mechanisms of Proteases

“…Further evidence for the medical relevance of research on glycosylated proteases can be found in the kallikrein field. Natural, inhomogeneously glycosylated KLK3 and glycan-free KLK3 were equally active, recombinant glycosylated KLK3 was three times more active [170,171]. Intriguingly, glycosylation patterns of KLK3 and KLK6 seem to correlate with prostate and ovarian cancer stages [172,173,174].…”

Prostate-specific antigen: a diagnostic marker and a tool for targeted delivery of drugs to prostate tumours

“…Also important is the finding that prostate metastases secrete the immunologically reactive PSA complex in prostatectomised patients [37], thus affording postsurgical diagnosis and treatment procedures. The PSA complex can be measured by immunoprecipitation with the DAKO antibody (a monoclonal mouse antihuman PSA, clone ER-PR8) followed by immunoblotting on SDS-PAGE.…”