THE PREDICTED AMINO-ACID-SEQUENCE OF HUMAN THIOREDOXIN IS IDENTICAL TO THAT OF THE AUTOCRINE GROWTH-FACTOR HUMAN ADULT T-CELL DERIVED FACTOR (ADF) - THIOREDOXIN MESSENGER-RNA IS ELEVATED IN SOME HUMAN TUMORS

The cDNA sequences of thioredoxin obtained by PCR cloning from human c olon cancer cells, human lymphoblastoid cells, and human liver have be en found to be identical with the cDNA sequence reported for the autoc rine growth factor, human adult T-cell leukemia derived factor (ADF). Recombinant human thioredoxin was 95% reduced by dithiothreitol and wa s a substrate for reduction by human thioredoxin reductase. Human non- small cell primary lung tumors from subjects who were not cigarette sm okers at the time of surgery showed significantly increased levels of thioredoxin mRNA compared to thioredoxin mRNA in paired normal human l ung tissue. Subjects who were smokers did not show a significant incre ase in lung tumor thioredoxin mRNA. The results of the study show that human thioredoxin and ADF are identical species and suggest that ther e may be increased production of thioredoxin (ADF) by some human cance rs.