一種新型gefitinib的衍生物(SP-101)誘導肺癌的細胞凋亡及腫瘤抑制作用

Abstract

Gefitinib是一個小分子的酪胺酸激酶抑制劑，具有抑制表皮生長因子接受器的活性，目前已被使用作為治療肺癌的臨床用藥。在本論文我們篩選出一種新穎的gefitinib衍生物，稱為SP-101，探討其誘發人類肺癌細胞凋亡及腫瘤抑制的抗癌活性。SP-101比其他gefitinib衍生物能更有效誘發肺癌細胞死亡，包括A549、H1299和CL3細胞株。利用表皮生長因子接受器的體外活性試驗，發現SP-101抑制表皮生長因子接受器的激酶活性之IC50值(抑制百分之五十之表皮生長因子接受器激酶活性的濃度)，在125-130 nM濃度範圍。SP-101會誘導caspase 3的活化和PARP蛋白的切割而誘發細胞的凋亡。有趣地，SP-101誘發肺癌細胞的凋亡和細胞生長的抑制作用比gefitinib效果更好。再者，SP-101會降低抗細胞凋亡survivin的基因和蛋白質表現，轉殖survivin 表現載體則會抵制SP-101所造成的細胞死亡。更重要是SP-101具有顯著抑制裸鼠中異體移植人類肺癌腫瘤體積和survivin的蛋白質表現。此外，分子電腦嵌合模型提供SP-101會與表皮生長因子接受器之激酶區域的ATP結合位置作用。綜合以上結果，顯示SP-101是一種新的gefitinib衍生物，具有誘發人類肺癌細胞之凋亡與抑制腫瘤形成的能力，並與降低survivin的表現有關。

Gefitinib, a small molecule tyrosine kinase inhibitor, inhibits epidermal growth factor receptor (EGFR) activity that has been used in clinical for lung cancer therapy. Here, we screen a novel synthetic compound (named as SP-101) from gefitinib derivatives and study its anticancer activities on the apoptotic induction and tumor inhibition in human lung cancer. SP-101 was more effective in inducing the cell death than other gefitinib derivatives in various human lung cancer cell lines, including A549, H1299 and CL3. The IC50 (the inhibition of 50% of EGFR kinase activity) value of SP-101 was around 125-130 nM using in vitro EGFR kinase assays. SP-101 induced the caspase 3 activation and poly ADP-ribose polymerase (PARP) protein cleavage for apoptosis. Interestingly, SP-101 was more sensitive on the induction apoptosis and growth inhibition than gefitinib in lung cancer cells. Furthermore, SP-101 reduced the gene and protein expression of survivin. Transfection with a survivin-expressed vector could resist the SP-101-induced cell death. More importantly, SP-101 significantly reduced the tumor size and survivin protein levels in the xenografted human lung tumors of nude mice. Besides, a molecular computational docking model indicates that SP-101 interacts with the ATP binding site of EGFR kinase domain. These results show that SP-101 is a novel gefitinib derivative in inducing apoptosis and tumor suppression related to the blockage of survivin in the human lung cancer.