Racial Differences in Expression Levels of miRNA Machinery-Related Genes, Dicer, Drosha, DGCR8, and AGO2, in Asian Korean Papillary Thyroid Carcinoma and Comparative Validation Using the Cancer Genome Atlas.

Aberrant regulation of microRNA (miRNA) machinery components is associated with various human cancers, including papillary thyroid carcinoma (PTC), which is the most common type of thyroid cancer, and a higher prevalent female malignancy. The purpose of this study is to investigate racial differences in mRNA expression levels of four miRNA machinery components, Dicer, Drosha, DGCR8, and AGO2, and their correlations with clinicopathological characteristics. Forty PTC samples from female Asian Korean PTC patients were enrolled. Using qPCR, we examined mRNA expression levels of the components and next validated our results by comparison with results of female white American in the TCGA PTC project. Interestingly, mRNA expression levels of the selected factors were altered in the TCGA PTC samples. However, only Drosha showed a significantly lower expression level in Asian Korean PTC samples. Furthermore, the mRNA expression levels of the four components showed no association with clinicopathological characteristics in both groups. On the other hand, positive correlations were observed between altered mRNA expression levels of Dicer and Drosha and DGCR8 and Drosha in TCGA PTC samples. These findings collectively revealed that altered mRNA expression levels of miRNA machinery components might be responsible for racial differences in the carcinogenesis of PTC.

Caffeic acid, morin hydrate and quercetin partially attenuate sulfur mustard-induced cell death by inhibiting the lipoxygenase pathway.

Sulfur mustard (SM) is an alkylating agent, which has been used as in chemical warfare in a number of conflicts. As the generation of reactive oxygen species (ROS), and adducts in DNA and proteins have been suggested as the mechanism underlying SM­induced cytotoxicity, the present study screened several antioxidant candidates, including tannic acid, deferoxamine mesylate, trolox, vitamin C, ellagic acid and caffeic acid (CA) to assess their potential as therapeutic agents for SM­induced cell death. Among several antioxidants, CA partially alleviated SM­induced cell death in a dose­dependent manner. Although CA treatment decreased the phosphorylation of p38 mitogen­activated protein (MAP) kinase and p53, p38 MAP kinase inhibition by SB203580 did not affect SM­induced cell death. As CA has also been reported as a 15­lipoxygenase (15­LOX) inhibitor, the role of 15­LOX in SM­induced cytotoxicity was also examined. Similar to the results observed with CA, treatment with PD146176, a specific 15­LOX inhibitor, decreased SM­induced cytotoxicity, accompanied by decreases in the production of tumor necrosis factor­α and 15­hydroxyeicosatetraenoic acid. Furthermore, the present study investigated the protective effects of two natural 15­LOX inhibitors, morin hydrate and quercetin, in SM­induced cytotoxicity. As expected, these inhibitors had similar protective effects against SM­induced cytotoxicity. These antioxidants also reduced the generation of ROS and nitrate/nitrite. Therefore, the results of the present study indicated that the natural products, CA, quercetin and morin hydrate, offer potential as adjuvant therapeutic agents for SM­induced toxicity, not only by reducing inflammation mediated by the p38 and LOX signaling pathways, but also by decreasing the generation of ROS and nitrate/nitrite.