Booth Nancy Lynn, Sayers Thomas J, Brooks Alan D, Thomas Cheryl L, Jacobsen Kristen, Goncharova Ekaterina I, McMahon James B, Henrich Curtis J
Molecular Targets Development Program, Center for Cancer Research, NCI-Frederick, Frederick, MD 21702, USA.
Cancer Immunol Immunother. 2009 Aug;58(8):1229-44. doi: 10.1007/s00262-008-0637-8. Epub 2008 Dec 17.
We have developed a high-throughput screen (HTS) to search for novel molecules that can synergize with TRAIL, thus promoting apoptosis of ACHN renal tumor cells in a combinatorial fashion. The HTS detects synthetic compounds and pure natural products that can pre-sensitize the cancer cells to TRAIL-mediated apoptosis, yet have limited toxicity on their own. We have taken into account the individual effects of the single agents, versus the combination, and have identified hits that are synergistic, synergistic-toxic, or additive when combined with TRAIL in promoting tumor cell death. Preliminary mechanistic studies indicate that a subset of the synergistic TRAIL sensitizers act very rapidly to promote cleavage and activation of caspase-8 following TRAIL binding. Caspase-8 is an apical enzyme that initiates programmed cell death via the extrinsic apoptotic pathway. Thus, these TRAIL sensitizers may potentially reduce resistance of tumor cells to TRAIL-mediated apoptosis. Two representative sensitizers were found to increase levels of p53 but did not inhibit the proteasome, suggesting that early DNA damage-sensing pathways may be involved in their mechanisms of action.
我们开发了一种高通量筛选（HTS）方法，以寻找能够与TRAIL协同作用的新型分子，从而以组合方式促进ACHN肾肿瘤细胞的凋亡。该高通量筛选可检测出能够使癌细胞对TRAIL介导的凋亡预先致敏，但自身毒性有限的合成化合物和纯天然产物。我们考虑了单一药物与联合用药的个体效应，并确定了与TRAIL联合使用时在促进肿瘤细胞死亡方面具有协同、协同毒性或相加作用的活性成分。初步的机制研究表明，一部分协同性TRAIL敏化剂在TRAIL结合后能非常迅速地促进半胱天冬酶-8的切割和激活。半胱天冬酶-8是一种顶端酶，可通过外源性凋亡途径启动程序性细胞死亡。因此，这些TRAIL敏化剂可能会降低肿瘤细胞对TRAIL介导的凋亡的抗性。发现两种代表性的敏化剂可提高p53水平，但不抑制蛋白酶体，这表明早期DNA损伤感应途径可能参与了它们的作用机制。
