Covalent Adducts Between Thioredoxin Reductase and Endogenous Electrophiles in Human Breast Cancer

摘要

We showed that endogenous electrophiles such as the cyclopentenone prostaglandin products of cyclooxygenase-2, and the estrogen metabolite 3,4- estrone quinone (3,4-EQ) are potent irreversible inhibitors of the antioxidant enzyme thioredoxin reductase (TrxR) . We present compelling evidence that formation of covalent complexes between electrophiles and TrxR in cells results in the conformational disruption of the tumor suppressor p53. We have prepared an antibody to the TrxR1 covalent complex with 3,4-EQ (anti-3,4-EQ)and have shown it to be a sensitive and selective reagent for the immunochemical detection of proteins in cells treated with the estrogen metabolite. We have also used anti-3,4-EQ in conjunction with anti-rabbit fluorescent secondary antibodies and found that it recognized an antigen in the nucleus of breast cancer cells treated with 3,4-EQ. We believe that anti-3,4-EQ is a promising reagent for detecting electrophilic estrogens that are important biomarkers for breast cancer.