8-hydroxydeoxyguanosine generated in the earthworm Eisenia fetida grown in metal-containing soil.

Heavy metal pollution of soil causes biological problems, such as mutagenicity to living organisms, including human beings. However, few methods have been developed to assess metal mutagenicity in soil. To avoid metal mutagenicity, an adequate bio-monitoring method is required. In the present study, to determine if the analysis of oxidative DNA damage generated in the earthworm is a useful bio-monitoring method for soil mutagenicity, the accumulation of 8-hydroxydeoxyguanosine (8-OH-dG), a major form of oxidative DNA damage, in Eisenia fetida (Savigny, 1826) treated with cadmium chloride (CdCl2) or nickel chloride (NiCl2) was analyzed. E. fetida was treated with Cd (10 or 200 microg/g soil) or Ni (10 or 200 microg/g soil) for 1, 2, and 3 weeks or 3 months. After metal exposure, the metal concentration in E. fetida was analyzed by atomic absorption spectrometry and the 8-OH-dG accumulated in E. fetida was analyzed by HPLC analyses and immunohistochemistry. Atomic absorption spectrometry revealed that Cd, but not Ni, accumulated within E. fetida. The 8-OH-dG levels in the DNA of E. fetida treated with Cd for 3 months were significantly higher than those in control E. fetida. Moreover, immunohistochemical analyses revealed that positive signals for 8-OH-dG accumulation in seminal vesicles were detected only in E. fetida treated with 10 microg of Cd for 3 months. Although some points remain unresolved, a bio-monitoring system analyzing the DNA damage generated in the earthworm might be useful for the assessment of the mutagenicity of soil contaminated with various heavy metals, such as Cd.

Bisphenol A induces endoplasmic reticulum stress-associated apoptosis in mouse non-parenchymal hepatocytes.

AIMS: the effects of bisphenol A (BPA) on NCTC Clone 1469, non-parenchymal hepatocytes, were examined to clarify the molecular basis of BPA-induced liver injury. MAIN METHODS: we analyzed the expression of C/EBP homologous protein (CHOP) mRNA, Bcl2 mRNA, caspase12, and glucose-regulated protein 78 kDa (GRP78)/Ig heavy chain-binding protein (BiP), to determine whether endoplasmic reticulum (ER) stress was involved in the 100 µM BPA-induced cell death. To examine the features of damaged hepatocytes, we analyzed the morphological changes in BPA-treated NCTC Clone 1469 by transmission electron microscopy. In addition, we analyzed the intracellular reactive oxygen species (ROS) level in BPA-treated NCTC Clone 1469 by the 2', 7'-dichlorofluorescein diacetate (DCFDA) method. KEY FINDINGS: increases in the expression of CHOP mRNA, caspase-12, and GRP78/BiP in NCTC Clone 1469-treated with 100 µM BPA were detected (CHOP, 1.42 fold; caspase-12, 1.33 fold; GRP78/Bip, 1.36 fold). These observations suggested that BPA induced ER stress-associated apoptosis. A morphological analysis revealed remarkable elongation of the rough ER, supporting the finding of ER stress. Intracellular ROS production was increased in NCTC Clone 1469-treated with BPA, and N-acetyl-l-cysteine (NAC) prevented the cell damage induced by BPA. However, these effects of BPA were not inhibited by estrogen receptor inhibitors. SIGNIFICANCE: we found that BPA induced ER stress-associated apoptosis in non-parenchymal hepatocytes. The ER stress is due to ROS production and is independent of estrogen receptors.

Enhancement of adipogenesis induction by conditioned media obtained from cancer cells.

White adipose tissue is a multifunctional endocrine organ that synthesizes and secretes cytokine-like proteins termed adipokines. In the present study, the effects of cancer-derived medium on adipogenesis were examined. We prepared conditioned media from cancer cell lines, and cultured preadipocytes in the conditioned media. After 10 days of culture, intracellular lipid droplet accumulation was measured. We observed that the conditioned media significantly induced adipogenesis or enhanced the adipogenesis induced by adipogenesis inducers. Although we could not define the factors, these undefined factors derived from cancer cells may induce adipogenesis, and the resulting adipogenesis may affect cancer development.