Dissertation/ Thesis
Interaction of sodium arsenite and H-Ras oncogene on carcinogenesis of human urothelial cells
| العنوان: | Interaction of sodium arsenite and H-Ras oncogene on carcinogenesis of human urothelial cells |
|---|---|
| Alternate Title: | 無機砷與H-Ras致癌基因在人類泌尿上皮細胞癌化之交互作用 |
| المؤلفون: | Yi-Chun Liao, 廖翊君 |
| Thesis Advisors: | Te-Chang Lee, 李德章 |
| سنة النشر: | 2014 |
| المجموعة: | National Digital Library of Theses and Dissertations in Taiwan |
| الوصف: | 102 Inorganic arsenite (iAs) is a human carcinogen. Numerous studies have shown that mutation-activated H-Ras is frequently observed in human urothelial carcinomas. The interaction between iAs, an environmental factor, and H-Ras, an oncogene, is not clear. To explore the effect of iAs and H-Ras on genotoxic and tumorigenesis effects, the experiments were conducted to establish the human urothelial cells stable ectopically expressing H-RasG12V, an activated H-Ras oncogene, as a platform to understand these interaction. The present results showed that H-RasG12V-transformed human urothelial cells (HUC-RAS) were more susceptible to arsenite-induced cell death, DNA damage, micronuclei (MN) formation and anchorage-independent growth than control cells (HUC-neo). Furthermore, iAs treatment induced higher intracellular levels of reactive oxygen species (ROS) in the HUC-RAS cells than in the HUC-neo cells. N-acetyl-L-cysteine, an antioxidant, could suppress the iAs-induced increases in ROS and genetic damage. This study further demonstrated that the intracellular glutathione levels were significantly elevated by the iAs treatment of the HUC-neo cells but that this effect was not observed in the HUC-RAS cells. The iAs treatment also induced higher superoxide dismutase activity in the HUC-neo cells than in the HUC-RAS cells. Alternatively, catalase activity was higher in the HUC-RAS cells than in the HUC-neo cells, but this enzyme was significantly suppressed by iAs. Moreover, iAs activated the ERK and JNK signaling pathways, which are involved in iAs-induced ROS production and genetic damage. These results suggest that elevated catalase activity in H-RasG12V-transformed cells is significantly suppressed by iAs via activation of ERK and JNK signaling pathways and hence attenuate the defense of H-RasG12V-transformed cells against iAs-induced oxidative injuries. In order to further clarify the interaction of iAs and H-Ras, the HUC-neo and HUC-RAS cells were continuously grown in the absence or presence of iAs at 0.5 μM for 30 passages and designated as to P0N, P0NA, R0R and P0RA, respectively. Of the sublines derived from subcutaneously tumor xenograft, P1R, P1RA, P2R and P2RA sublines were established. By using Illumina HumanHT-12 Expression BeadChip Whole Genome arrays cDNA analysis, 878 genes were differentially expressed among these sublines. IPA-ranked signaling networks of diseases and functions identified altered the metastasis, cell movement, migration of cells and inflammatory response signaling networks. It's worth noting that among these differentially expressed of inflammatory-related gene IL1α, IL1β, IL6 and IL8, were up-regulated in the sublines derived from iAs exposed cells as compared with those without chronic exposure to iAs. In aspects of ability to tumors formation, the P0RA sublines growth slower than P0R sublines on subcutaneously tumor xenograft, but P1RA sublines have more tumorigenic ability than P1R sublines. In this model, liver of nude mice derived from P0RA cells, and P1RA sublines have develop the necrosis phenomena and inflammation cells accumulation around the blood vessels, but not from P0R cells and P1R sublines. In addition, the data also demonstrated P2R and P2RA sublines obvious promote the lung metastasis in the NOD-SCID mouse by tail vein injection. Altogether, this study provides evidence for exposure of iAs modulates the tumorigenesis of H-Ras transformed human urothelial cells. However, further research is needed to explore the complex mechanisms. Further studies will be needed to clarify how long term exposure of iAs can induce the expression of inflammatory-related gene in cancer cells. These data may be valuable for further understanding in molecular mechanism of arsenic carcinogenicity. |
| Original Identifier: | 102YM005550013 |
| نوع الوثيقة: | 學位論文 ; thesis |
| وصف الملف: | 86 |
| الاتاحة: | http://ndltd.ncl.edu.tw/handle/21396448915230136409 |
| رقم الانضمام: | edsndl.TW.102YM005550013 |
| قاعدة البيانات: | Networked Digital Library of Theses & Dissertations |
| الوصف غير متاح. |