Identification and Targeting of Prostate Cancer Cells Via Molecular Recognition Elements

Among males in the United States, prostate cancer is the most-diagnosed cancer and is the second leading cause of cancer-related deaths.  Current detection and therapeutic methods are not specific for the disease.  The current standard in detection, prostate specific antigen (PSA) levels in the blood, was recently given a “D” grade by the U.S. Preventative Services Task Force.  Therefore, it is no longer recommended for use.  To address this problem, molecular recognition elements (MREs) that specifically bind to prostate cancer cells and not benign prostate cells have been selected.  This was done through the Selective Evolution of Ligands by Exponential Enrichment (SELEX).  Using this in vitro selection process, a library of 10⁹ yeast-displayed antibody fragments were exposed to a prostate cancer cell line.  Antibody fragments that bound to those cells were then amplified and incubated with benign prostate cells.  Those antibody fragments that did not bind to these cells were amplified.  Seven rounds of positive and negative selection were completed and a small number of antibody fragment MREs have been identified.