title: Direct interaction with cellular targets as the mechanism for chromium carcinogenesis.
abstract: The carcinogenic activity of chromium appears to be due to its direct interaction with cellular targets and not to nonspecific solid-state carcinogenesis. Chromium was evaluated at 2 valences, Cr+3 (as CrC13) and Cr+6 (as K2Cr2O7), for its toxicity, transforming activity, and ability to induce chromosomal aberrations in tertiary cultures of mouse fetal cells. The ID50 (dose for 50 percent inhibition of cell growth) of Cr+3 was approximately 4 times greater than that of Cr+6 after 96 h of exposure, and about 29 times greater than that of Cr+6 after 1 h of exposure. At equitoxic concentrations, both chromium valences induced the same degree of morphologic changes and alterations of growth behavior, but Cr+6 produced more chromosomal aberrations. Using autoradiography in an established cloned line of mouse cells, unscheduled DNA synthesis was observed in cells previously exposed to Cr+6 but not in cells previously exposed to Cr+3.
mesh_terms: D000818:Animals; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced* / Q000473:pathology; D002478:Cells, Cultured; D055598:Chemical Phenomena; D002621:Chemistry; D002857:Chromium / Q000009:adverse effects*; D002869:Chromosome Aberrations; D002875:Chromosomes; D004260:DNA Repair; D051379:Mice; D008807:Mice, Inbred BALB C; D009374:Neoplasms, Experimental / Q000139:chemically induced / Q000473:pathology
chemical_list: D002857:Chromium