KLF8 屬於 Krüppel-like factor 家族成員之一的轉錄蛋白，具有3 個高度保留區的 C2H2 zinc finger domain 能與目標基因啟動子內的 CACCC 序列結合。KLF8 對於致癌基因的轉形扮演著重要角色，在具有侵襲能力的癌症中，會有 KLF8 的高度表現，但是 KLF8 對於胃癌細胞的影響尚未完全明瞭。在此研究，我們發現在胃癌細胞中，KLF8 會促進 cofilin 蛋白的表現。為了驗證在胃癌細胞中 KLF8 可以調控 cofilin，首先利用 luciferase reporter assay 來進行分析。證實在 AGS 胃癌細胞中 KLF8 會直接與 CFL-1 promoter 結合，接著透過定量 PCR 及西方墨點法的方式亦證實 cofilin 的mRNA 與蛋白有明顯增加。反之，藉由 siRNA 或是 shRNA knockdown 後，其蛋白表現量則受到抑制。總括來說，我們的實驗顯示 KLF8 透過直接的結合到 CFL-1 promoter 上，促進其轉錄作用的發生，促使 cofilin 蛋白的表現量增加。
Krüppel-like factor 8 (KLF8) is a transcription factor belonged to the Krüppel-like factor (KLF) family. KLFs bind CACCC elements in target gene promoter by three highly conserved C2H2 zinc finger domain. KLF8 plays a key role in oncogenic transformation and highly overexpressed in several types of invasive human cancer. However, the effect of KLF8 in gastric cancer cell remains unknown. In this study, we report that KLF8 promotes cofilin protein expression in gastric cancer cell. Using 2-D gel electrophoresis, we have identified cofilin as a KLF8 downstream target. KLF8 activated CFL-1 gene promoter which contain three CACCC motifs as determined by luciferase reporter assay in gastric cancer cell line AGS. Overexpression of KLF8 increase cofilin expression as determined by quantitative real time PCR and western blot assay. Similarly, KLF8 knockdown decrease cofilin protein expression as determined by siRNA or shRNA. Taken together, our results identified that KLF8 increases cofilin protein expression via KLF8 directly bind to CFL-1 promoter.
