Eur J Cancer 2011 Nov;47 (16): 2471-8. [IF:4.944]
Death Receptor 5 and cellular FLICE-inhibitory protein regulate pemetrexed-induced apoptosis in human lung cancer cells.
Su L , Liu G , Hao X , Zhong N , Zhong D , Liu X , Singhal S .
School of Life Sciences, Shandong Provincial Key Laboratory Of Animal Cells and Developmental Biology, Shandong University, Jinan, People's Republic of China.
济南山东大学生命科学学院，山东省动物细胞与发育生物学重点实验室
Abstract
Pemetrexed is a clinically available anti-folate therapeutic agent used in combination with cisplatin for the management of patients with malignant pleural mesothelioma and advanced non-small cell lung cancer. Pemetrexed inhibits three enzymes in purine and pyrimidine synthesis necessary for precursor DNA nucleotides which in turn disrupts growth and survival of normal and cancer cells. The mechanism by which pemetrexed induces apoptosis remains largely uncharacterised. In the current study, we examined the downstream effect of pemetrexed in inducing apoptosis in lung cancer cells. We showed that pemetrexed induced apoptosis via up-regulation of Death Receptor 5 (DR5), an important death receptor for tumour necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL). In addition, we discovered a synergistic effect of combination pemetrexed and recombinant TRAIL in inducing apoptosis. Modulating DR5 induction by small interfering RNA abrogated the ability of pemetrexed to induce apoptosis. In addition, silencing of C/EBP homologous protein (CHOP) expression reduced DR5 expression, demonstrating that the transcriptional factor CHOP has a pivotal role on DR5 up-regulation following pemetrexed treatment. In addition, enforced expression of cellular FLICE-inhibitory protein (c-FLIP), a known inhibitor of caspase 8, protected neoplastic cells from apoptosis despite pemetrexed and/or TRAIL therapy. Thus, our findings demonstrate the efficacy and mechanistic underpinnings of pemetrexed-induced apoptosis, and they suggest pemetrexed may have clinical utility when used in combination with TRAIL for the management of patients with lung cancer.
摘要
培美曲塞是临床上和顺氨氯铂联合用于恶性胸膜间皮瘤和高级别的非小细胞肺癌的抗叶酸制剂。培美曲塞可以抑制作为DNA核苷酸前体的嘌呤和嘧啶合成所必须三种酶，从而扰乱正常细胞和肿瘤细胞的生长和存活。培美曲塞产生作用的机制如凋亡在很大程度上还不为人所知。在最近的研究中，我们研究了培美曲塞在诱导肺癌细胞凋亡的下游作用。我们的结果显示培美曲塞是通过上调死亡受体5（DR5）的表达来诱导细胞凋亡的，DR5是肿瘤坏死因子相关凋亡诱导配体（TRAIL）的重要死亡受体。此外我们发现培美曲塞和TRAIL重组体在诱导凋亡上的合成效果。培美曲塞诱导凋亡的能力是通过DR5阻止小干扰RNA的作用产生的。此外，C/EBP同源蛋白（CHOP）表达沉默可以减少DR5的表达，证实了在经过培美曲塞治疗后，转录因子CHOP在上调DR5表达上的关键作用。此外，增强的细胞FLICE抑制蛋白(c-FLIP)——已知的caspase 8抑制剂，可以保护新生细胞免受来自培美曲塞和/或TRAIL治疗诱导的凋亡。因此，我们的研究证实培美曲塞诱导产生凋亡的有效性和机制。提示了当联合TRAIL用于肺癌患者的治疗时，培美曲塞的临床应用有效性。
