Identification of human Thioredoxin as a potent redox protein in carcinogenesis

Thioredoxins ("TRX") are ubiquitous 12-kDa oxidoreductase enzyme containing a dithiol-disulfide active site facilitating the reduction of other proteins by cysteine thiol-disulfide exchange. When thioredoxin levels are elevated there is increased cell growth and resistance to the normal mechanism of
programmed cell death. An increase in thioredoxin levels seen in many human primary cancers compared tonormal tissue appears to contribute to increased cancer cell growth and resistance to chemotherapy. Mechanisms by which thioredoxin increases cell growth include an increased supply of reducing equivalents forDNA synthesis, activation of transcription factors that regulate cell growth, and an increase in the sensitivity of cells to other cytokines and growth factors thereby thioredoxin offers a target for the development of drugs totreat and prevent cancer.