Improved cancer specificity in PSA assay using Aleuria aurantia lectin coated Eu-nanoparticles for detection

The objective was to study the differences in PSA fucosylation obtained from LNCaP and PC-3 prostate cancer cell lines, seminal plasma PSA and recombinant precursor form of PSA expressed in baculovirus, using Aleuria aurantia lectin (AAL). The aim was to assess whether differences in fucosylation (Fucα1-6/3GlcNAc carbohydrates) of PSA either in urine, blood or tissue enable the discrimination of patients with prostate cancer (PCa) from benign prostatic hyperplasia (BPH) and young males.

Two novel lectin-immunoassays were developed for the analysis of fucosylation of PSA by measuring the time-resolved fluorescence of europium chelate. The lectin-immunoassays utilize free PSA-specific Fab-fragments for capturing the analyte and either europium-labeled AAL or AAL coupled to Eu(III)-chelate-dyed nanoparticles for the detection of Fucα1-6/3GlcNAc carbohydrates on PSA.

Using the novel lectin-immunoassays, we showed higher levels of Fucα1-6/3GlcNAc on PSA derived from LNCaP and PC-3 cells compared to seminal plasma PSA. With the more sensitive nanoparticle-based lectin-immunoassay we detected a statistically significant increase in the PSA fucosylation in PCa tissue compared to benign tissue (p=0.001) and in urine from PCa patients compared to BPH patients (p=0.030), and an even greater discrimination (p=0.010) when comparing BPH patients to PCa patients with Gleason score≥7.

AAL coupled to Eu(III)-chelate-dyed nanoparticles improved the sensitivity of immunoassay for the detection of Fucα1-6/3GlcNAc structures on PSA. The preliminary findings show an increased fucosylation in PCa compared to benign conditions. Further validation is required to assess the true clinical utility of AAL in PCa diagnosis.