| 摘要: | 口腔癌佔國人男性癌症死亡原因之第四名，到目前為止其整體成因未明。一般咸 信，除?煙、酒、檳榔之?為習性外，維繫整個基因體穩定的DNA 修補系統?發生缺 陷，也極可能與口腔癌癌化過程有關。因此，對於DNA 修補系統基因之全面性探討， 將有助於瞭解整個口腔癌化的機轉。 我們?續性的研究已經發現，在DNA雙股斷?“非同源末梢黏合DNA修補 (NHEJ)” 系統中的XRCC4, Ku70 及Ku80 等基因，其特殊位點上的基因型與口腔癌的?患?有 明顯的關?性。我們已經收集到的口腔癌及能與其對照的無癌健康組，已經達到約各 七百位的高水準，未?三?我們期許將此研究族群擴增到各一千五百位以上，成為具 全球頂級競爭?的團隊。基於過去幾?重要的發現，我們將分別從人?族群及細胞模 式，?探討“NHEJ 在口腔癌癌化過程中所扮演的角色?。我們的設計上亦同時兼顧? 基因型與表現型的交互配合，?兼可以建?進?對於抗口腔癌藥物篩檢的優勢平臺， 可以?具有系統性與完整性。 第一?將針對NHEJ 之其他基因如ligase 4, DNA-PKcs, Artemis, XLF 等進?單核 ?酸多型性的基因型鑑定，同時，基因與基因間的交互作用，以及環境因子與基因遺 傳因子對於口腔癌的共同效應，?將一併進?分析。第二?將使用可買到的(如SCC-25, NA, HSC-4 及KB 等)及自?初代培養的口腔癌細胞株，針對各型NHEJ 能?等表現型 以及各基因在mRNA 及蛋白質層面於口腔癌化前後的變化進?探究。第三?則由於過 去我們曾以藥物誘發口腔癌小鼠的癌細胞，進?抗癌藥物的尋求，我們發現將砒霜之 主成份三氧化二砷佐以ditihiothretol，可以專一性?死口腔癌細胞而?會?死正常細 胞，我們新的計畫將以人?細胞為重心，以三氧化二砷佐以ditihiothretol 或其他的藥 物?進?嶄新藥物的快篩研究，以及此?有效藥物對於細胞內NHEJ 能?等表現型的 作用機制。本計劃將有助於探究基因與基因間、基因與環境間、及NHEJ 在口腔癌化 過程中所扮演的角色等重要議題，?可以提供口腔癌個人化基因治?之嶄新方向。
Oral cancer is ranked the forth leading cause of cancer incidence among Taiwanese male population. Until now, the overall mechanism(s) behind the development of oral cancer remains unrevealed. It is believed that in addition to environmental factors, such as smoking, alcohol drinking, and betel quid chewing, the subtle deficiencies of DNA repair systems, caretakers care of the genome, maybe also related to oral carcinogenesis. Therefore, the systematic understanding of the genotypes and the phenotypes of these DNA repair genes will help us to reveal the oral carcinogenesis progression. In the previous continuous research, we have indeed found that the genetic polymorphic variations of XRCC4, Ku70, and Ku80, members of the important system for DNA double strand break repair, non-homologous end-joining (NHEJ), are associated with oral cancer susceptibility. Our population is about 700 patients and 700 age- and gender-matched non-cancer controls, and the sample size will be enlarged to 1,500 in each group, which is very competing and powerful in worldwide oral oncology research. Thus in the next 3-year project, we aim to elucidate the contribution of NHEJ to oral carcinogenesis via multiple levels including human population, and cell model, respectively. An overall genotype-phenotype study will be conducted, and the oral cancer prediction system will be established. In the first year, we will genotype the single nucleotide polymorphisms in other NHEJ genes, such as DNA ligase 4, DNA-PKcs, Artemis, XLF, and evaluated the associations between these polymorphisms and oral cancer risk. By the way, the effects of gene-gene interactions, and the environmental factors will be combined with these genetic factors to evaluate their combined contribution to oral cancer etiology. In the second year, using oral cancer primary cultured cells to compare with counterpart normal cells from the same patients, their differences in phenotypes such as in vitro and in vivo NHEJ and overall double strand break repair capacities will be investigated. Some commercial avaible oral cancer cells, such as SCC-25, NA, HSC-4, and KB, will be used as standard controls. By this platform, the differential expression patterns between cancer and normal cells of the NHEJ proteins will be examined by Northern and Western Blotting, separately. In the third year, we are going to investigate the effects of potential anti-oral cancer drugs, and their cellular mechanisms using the cell lines both from commercial and primarily culture sources. In 2010, we have successfully and specifically kill the tongue cancer cells from the 4-NQO plus arecoline-induced tongue cancer mice by a novel combination of dithiothretol and arsenic. We shall use the human oral cancer cells as a platform for screening potential cancer drugs, and investigating their effects on cellular functions including NHEJ repair capacity. We believe our future work can be helpful to elucidate the gene-gene interaction, gene-environment interaction and the contribution of NHEJ system to oral carcinogenesis, and provide new evidence and novel strategies for oral cancer personalized therapy via pharmacogenomics. |
