乙醯化作用是芳香胺類致癌物主要代謝路線，經由細胞質內N-乙醯轉移酵素(N-acetyltransferase,NAT)利用乙醯輔助酵素A的乙醯基來進行乙醯化。改變肝中乙醯轉移酵素活性與人類癌症如膀胱和乳癌的產生有關。BHT Butylated hydroxyanisol (BHA) 和Butylated hydroxytoluene (BHT)是合成酚類抗氧化劑，已經被報告含有抗癌的特性。例如能抑制由實驗老鼠的肝癌和膀胱癌的產生。但是目前沒有文獻報告有關BHA和BHT抑制大白鼠 (SD) 白血球細胞乙醯轉移酵素活性及人類膀胱癌細胞NAT酵素的活性。因而此研究計劃主要專注於BHA和BHT能否影響人類膀胱癌細胞NAT的活性、細胞週期、DNA 斷裂、細胞形態。本研究發現白血球細胞內 AF (aminofluorene) 的乙醯化，BHA 和 BHT 對大白鼠 (SD) 白血球細胞乙醯轉移酵素活性的抑制作用時間可達24小時。 BHA和BHT能抑制人類膀胱癌細胞(T-24) NAT的活性、明顯地抑制癌細胞的細胞週期(合成期)、也會造成癌細胞中DNA的斷裂。; N-acetylation, a major metabolic pathway for arylamine carcinogen,is catalyzed by cytosolic arylamine N-acetyltransferase(NAT) using acetyl coenzymeA as an acetyl group. Attenuation of NAT activity is associated with several disease processes such as bladder and breast cancer.Butylated Hydroxyanisole (BHA) and Butylated Hydroxytolene(BHT) are synthetic phenolic antioxidants,had been demonstrate to possess cancer preventive properties such as inhibit the liver and bladder cancer development in experimental rats.However,there is no reports to address BHA and BHT affect NAT activity of bladder cancer cells. Thus our proposed study focus on the effect of BHA and BHT on the NAT activity from S-D rat WBC and human bladder cancer cells(T-24).We also examined the Cell Cycle via Flow cytometry,DNA fragmentation,and cell morphology.The result shows The NAT activity of S-D rat WBCand T-24 were supressed by BHA and BHT in a dose-dependent manner.The BHA and BHT also inhibits the S-phase of T-24 cell cycle.We found that BHA and BHT induced T-24 cell DNA fragmentation and Cell morphology destruction.
