KLK2- and KLK11-binding proteins as novel class of recombinant capture ligands useful for improved Prostate Cancer diagnostics

Lucie Marečková, Hana Petroková and Petr Malý

Laboratory of Ligand Engineering, Institute of Biotechnology AS CR, v. v. i., Vídeňská 1083, 142 20 Prague, Czech Republic

lucie.mareckova@img.cas.cz, petr.maly@img.cas.cz

Human kallikrein 2 (KLK2) and kallikrein 11 (KLK11), members of the kallikrein gene family of trypsin-like serine proteases, have recently been indicated as novel promising oncomarkers of the prostate cancer (PC), the second most common cause of male cancer-related deaths in the Western world. Currently, the only clinically validated diagnostic approach for the PC diagnosis relies on serum level detection of Prostate Specific Antigen (PSA), known also as KLK3, and the assessment of the ratio between total and free PSA. Yet clinically largely used, the antibody-based PSA assay fails in prediction of early stages of PC and does not precisely distinguish between malign form of the PC and benign prostate hyperplasia. This leads to the identification of group of false indicated PC patients that have to undergo cost-effective and risky prostate tissue biopsy. To overcome this problem together with limitations of PSA detection for the early detection of the PC, there is a need to develop multifactorial ELISA kits or novel biosensors, as more complex PC prognosticators, for more accurate prediction of cancer presence, stage and metastasis.

Here we present generation and characterization of novel binders targeting human KLK2 (called KLA binders) and KLK11 (HIP binders) that were selected by ribosome display from a high-complex combinatorial library, derived from an albumin-binding domain (ABD) scaffold. We demonstrate a preliminary assessment of binding properties of the most promising KLA and HIP variants and their thermal stability studies performed by Thermal shift assay (TSA).

This work was funded by the grant FR-TI4/667 by Ministry of Industry and Trade of the Czech Republic and supported by grant from BIOCEV – Biotechnology and Biomedicine Centre of Academy of Sciences and Charles University in Vestec, project supported from European Regional Development Fund.