Detection of Alpha-Methylacyl-CoA Racemase (AMACR), a Biomarker of Prostate Cancer, in Patient Blood Samples Using a Nanoparticle Electrochemical Biosensor

Abstract

Although still commonly used in clinical practice to screen and diagnose prostate cancer, there are numerous weaknesses of prostate-specific antigen (PSA) testing, including lack of specificity and the inability to distinguish between aggressive and indolent cancers. A promising prostate cancer biomarker, alpha-methylacyl-CoA racemase (AMACR), has been previously demonstrated to distinguish cancer from healthy and benign prostate cells with high sensitivity and specificity. However, no accurate clinically useful assay has been developed. This study reports the development of a single use, disposable biosensor for AMACR detection. Human blood samples were used to verify its validity, reproducibility and reliability. Plasma samples from 9 healthy males, 10 patients with high grade prostatic intraepithelial neoplasia (HGPIN), and 5 prostate cancer patients were measured for AMACR levels. The average AMACR levels in the prostate cancer patients was 10 fold higher (mean(SD) = 0.077 (0.10)) than either the controls (mean(SD) = 0.005 (0.001)) or HGPIN patients (mean(SD) = 0.004 (0.0005)). At a cutoff of between 0.08 and 0.9, we are able to achieve 100% accuracy in separating prostate cancer patients from controls. Our results provide strong evidence demonstrating that this biosensor can perform as a reliable assay for prostate cancer detection and diagnosis.

Recent advances in biosensor development for the detection of cancer biomarkers

“…Electrochemical PSA biosensors have also utilized MWCNTs as immobilization matrix (Salimi et al, 2013). Apart from PSA, another potential prostate cancer biomarker is alpha-methyl-acyl-CoA racemase (AMACR) for which a biosensor is developed and validated with human blood samples for its reproducibility (Lin et al, 2012).…”

Detection of α‐Methylacyl‐CoA Racemase in Serum and Urine Using a Highly Sensitive Electrochemical Immunodetector

“…Detection of AMACR was previously carried out in serum with the lowest concentration at µg/µL 7. In the present work, detection of AMACR in serum was first demonstrated on the ng/mL level.…”

“…Detection of AMACR on the femto‐gram/mL level was achieved directly in patient urine without a sample preparation step and without the use of labeled reagents. Another sensor‐based detection of AMACR was made using a iridium nanoparticle‐based H 2 O 2 electrochemical sensor 7. The sensor was used to detect H 2 O 2 that was released in the AMACR‐catalyzed conversion of ( 2R )‐pristanoyl‐CoA to ( 2S )‐pristanoyl‐CoA.…”

Preparation and characterization of the antibody recognizing AMACR inside its catalytic center

“…This may be associated with the intracellular localization of the protein and its inaccessibility for antibodies. On the other hand, recent studies have revealed the presence of AMACR in biological fluids of patients suffering from cancer (24,25), which indicates the obvious desirability for obtaining and for the characterization of a wide variety of antibodies against AMACR.…”