Preparation of a novel monoclonal antibody specific to DARPP-32.
DARPP-32 (dopamine and cAMP-regulated phosphoprotein) is the bifunctional protein that can act as a PP1 inhibitor or a PKA inhibitor. Here we have for the first time generated a monoclonal antibody against DARPP-32. Enzyme-linked immunosorbent assay (ELISA) and Western immunoblotting were used to screen the hybridomas. As a result, one MAb named Y8 (IgG1) was characterized, which bound to the native DARPP-32 protein. Then the MAb was used to detect the expression of DARPP-32 in gastric cancer cells and tissues. DARPP-32 was found to be downregulated in multidrug-resistant gastric cancer cells compared with drug-sensitive cells. DARPP-32 was also found to be upregulated in poorly differentiated gastric cancer tissues compared with well-differentiated and moderately differentiated gastric tissues. The results showed that DARPP-32 might play an important role in carcinogenesis and multidrug resistance of gastric cancer.