DNA Single-Strand Breaks and Cytotoxicity Induced by Chromate(VI), Cadmium(II), and Mercury(II) in Hydrogen Peroxide-Resistant Cell Lines

Abstract

The induction of cytotoxicity and DNA single-strand breaks by chromium(VI), cadmium(ll), and mercury(ll) were compared in H202-resistant Chinese hamster ovary (CHOR) cells and parental (CHOP) cells. Using a colony-forming assay, CHOR cells were found to be significantly more resistant than CHOP cells to the cytotoxicity caused by CdCI2 and HgCI2, but not to that caused by Na2CrO4. However, the DNA single-strand breaks produced by each of these metals were significantly lower in the CHO cells. With respect to chromium reduction, the level of chromium(V) in CHOR cells was decreased. The role of intracellular active oxygen in the heavy metal-induced DNA damage and cytotoxicity is discussed. Environ Health Perspect 102(Suppl 3): 341-342 (1994).

DNA Double-Strand Breakage as an Endpoint to Examine Metal and Radionuclide Exposure Effects to Water Snakes on a Nuclear Industrial Site

“…This latter process occurs in addition to direct breakage from ionizing radiation or from induction of free radicals (Sugg et al 1995). Heavy metals may also cause direct breakage through the induction of oxygen radicals (Hoffman and Heinz 1998;Snow 1991;Tsuzuki et al 1994). The presence of U in muscle tissue and the correlation to the observed DDSB ( Table 6) allows speculation that gamma-emitting daughter products of U in Tim's Branch might have had some effect on the integrity of the DNA of these organisms.…”

“…However, other studies have demonstrated a protective effect of Se on Hg exposure at the intracellular level (Lourdes 1991). Moreover, Cr is well known to inhibit DNA repair and can form intermolecular DNA cross-links (Snow 1991;Tsuzuki et al 1994).…”

<i>Gingko biloba</i> Extract Ameliorates Cadmium-Induced Hepatotoxicity in Experimental Animals

“…This is in contrast with the study of Samir [20] who reported significant decrease in ALP activities and Kobayashi [21] who reported no observable changes in Liver ALP activity in the Cd-exposed rats. Many studies have established various adverse effects of cadmium, such as its influence on mitochondrial function, enhancement of lipid peroxidation, and breakage of DNA chain [19,[22][23][24]. Following the administration of Ginkgo biloba in groups C (Cd + Ld GBE) and D (Cd + Hd GBE), ALP activities were significantly decreased in groups C (Cd + Ld GBE) (0.14±0.00) and D (Cd + Hd GBE) (0.14±0.00) when compared with that of group B (Cd), the negative control group.…”

Cadmium‐induced gene expression is regulated by MTF‐1, a key metal‐responsive transcription factor

“…It potentates this damage by inhibiting DNA repair and thereby, enhancing oxidative stress (Hartwig, 1994;Tsuzuki et al, 1994). It has been postulated that since (a) DNA gyrase/topoisomerases are integral components in DNA repair (Hickson et al, 1990) and (b) DNA-damaging agents elevate the levels of topoisomerase in cultured cells and tumors (Kikuchi et al, 1997), any increased expression of these genes would be a likely consequence of cadmium exposure.…”