A cell-based high-throughput screen to identify synergistic TRAIL sensitizers.
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.
Booth
Nancy Lynn
NL
Molecular Targets Development Program, Center for Cancer Research, NCI-Frederick, Frederick, MD 21702, USA. nancylynnbooth@gmail.com
Sayers
Thomas J
TJ
Brooks
Alan D
AD
Thomas
Cheryl L
CL
Jacobsen
Kristen
K
Goncharova
Ekaterina I
EI
McMahon
James B
JB
Henrich
Curtis J
CJ
D000230:Adenocarcinoma / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000302:isolation & purification* / Q000494:pharmacology*; D017209:Apoptosis; D053181:Caspase 8 / Q000187:drug effects / Q000378:metabolism*; D045744:Cell Line, Tumor; D004354:Drug Screening Assays, Antitumor; D004357:Drug Synergism; D006801:Humans; D007680:Kidney Neoplasms / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000502:physiology; D046988:Proteasome Endopeptidase Complex / Q000187:drug effects / Q000378:metabolism; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000187:drug effects / Q000378:metabolism
D000970:Antineoplastic Agents; D053221:TNF-Related Apoptosis-Inducing Ligand; D016159:Tumor Suppressor Protein p53; D053181:Caspase 8; D046988:Proteasome Endopeptidase Complex