H6D Polymorphism Specific Detection of NAG1 in Human Serum

The nonsteroidal anti-inflammatory drug-activated gene (NAG1), also referred to as GDF-15 or MIC-1, is a member of the TGF-β superfamily of cytokines. NAG1 is implicated in prostate cancer, and levels of NAG1 protein in the serum of patients with metastatic prostate carcinomas are significantly higher than those from patients with breast and colorectal carcinomas. A correlation of the most common and wellcharacterized position 6 histidine-to-aspartate (H6D) polymorphism is associated with sporadic and familial cases of PCa, and the allelic H6D variation of NAG1 is an independent predictor of the presence of metastasis.

The lack of widely available commercial reagents to measure NAG1 protein concentration and detect serum protein variants compels the development of additional antibodies and a highly sensitive ELISA for NAG1 protein. We have undertaken production of a novel NAG1 serum assay allowing for the detection of total NAG1 serum levels. We have produced multiple antibodies that allow for detection of total NAG and that can distinguish between the His6 and Asp6 variants. Additionally we have produced recombinant NAG1 protein standards. The goal is to create a commercially available ELISA with a low background and high signal-to-noise ratio that is capable of detecting serum NAG1 at concentrations of 25 pg/mL or lower.