• 대한본초학회지
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• 제39권4호
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• pp.37-45
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• 2024

Objectives : This study aimed to elucidate antioxidant activity of chrysin in polyinosinic-polycytidylic acid (poly-IC) and lipoteichoic acid-induced RAW 264.7 mouse macrophages. Methods : RAW 264.7 co-stimulated with poly-IC and lipoteichoic acid were incubated with chrysin at concentrations of 25 and 50 µM. Hydrogen peroxide production was measured with dihydrorhodamine 123 assay. Nitric Oxide (NO) production was evaluated by griess reagent assay. Results : For 16 h, 18 h, 20 h, 22 h, and 24 h incubation, chrysin at the concentration of 25 and 50 µM significantly suppressed hydrogen peroxide production in poly-IC and lipoteichoic acid-induced RAW 264.7. In details, production of hydrogen peroxide in 'poly-IC and lipoteichoic acid'-stimulated RAW 264.7 treated for 16 h with chrysin at concentrations of 25 and 50 µM was 83.84% and 79.3% of the control group treated with poly-IC and lipoteichoic acid only, respectively; the production of hydrogen peroxide for 18 h was 84.36% and 79.93%, respectively; production of hydrogen peroxide for 20 h was 85.68% and 80.22%, respectively; production of hydrogen peroxide for 22 h was 85.81% and 79.95%, respectively; production of hydrogen peroxide for 24 h was 86.01% and 80.18%, respectively. Additionally, chrysin at the concentration of 5, 10, 25, and 50 µM significantly inhibited NO production in THP-1 human monocytic cell line. Conclusions : Chrysin might have anti-oxidative activity related to its inhibition of hydrogen peroxide production in 'poly-IC and lipoteichoic acid'-stimulated RAW 264.7.

• Journal of Radiation Protection and Research
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• 제43권2호
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• pp.66-74
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• 2018

Background: Tumor response to anticancer therapies can much be influenced by microenvironmental factors. In this study, we determined the effect of these microenvironmental factors on DNA methylation using A549 human lung adenocarcinoma cell line. Materials and Methods: We subjected A549 cells to various conditions mimicking tumor microenvironment including hypoxia, acidosis (sodium lactate), oxidative stress ($H_2O_2$), bystander effect (supernatant from doxorubicin (Dox)-treated or irradiated cells), and immune cell infiltration (supernatant from THP-1 or Jurkat T cells). Genomic DNA was isolated from these cells and analyzed for DNA methylation. Clonogenic cell survival, gene expression, and metabolism were analyzed in cells treated with some of these conditions. Results and Discussion: We found that DNA methylation level was significantly decreased in A549 cells treated with conditioned media from Dox-treated cells or Jurkat T cells, or sodium lactate, indicating an active transcription. To determine whether the decreased DNA methylation affects radiation sensitivity, we exposed cells to these conditions followed by 6 Gy irradiation and found that cell survival was significantly increased by sodium lactate while it was decreased by conditioned media from Dox-treated cells. We further observed that cells treated with conditioned media from Dox-treated cells exhibited significant changes in expression of genes including BAX and FAS (involved in apoptosis), NADPH dehydrogenase (mitochondria), EGFR (cellular survival) and RAD51 (DNA damage repair) while sodium lactate increased cellular metabolism rather than changing the gene expression. Conclusion: Our results suggest that various tumor microenvironmental factors can differentially influence DNA methylation and hence radiosensitivity and gene expression in A549 cancer cells.