Escin, a pentacyclic triterpene, chemosensitizes human tumor cells through inhibition of nuclear factor-kappaB signaling pathway.
Agents that can enhance tumor cell apoptosis and inhibit invasion have potential for the treatment of cancer. Here, we report the identification of escin, a pentacyclic triterpenoid from horse chestnut that exhibits antitumor potential against leukemia and multiple myeloma. Whether examined by esterase staining, phosphatidyl-serine staining, DNA breakage, or caspase-mediated poly(ADP-ribose) polymerase cleavage, escin potentiated tumor necrosis factor (TNF)-induced apoptosis but inhibited tumor cell invasion. This correlated with the down-regulation of bcl-2, cellular inhibitor of apoptosis protein-2, cyclin D1, cyclooxygenase-2, intercellular adhesion molecule-1, matrix metalloproteinase-9, and vascular endothelial growth factor, which are all regulated by the activation of the transcription factor NF-kappaB. When examined by electrophoretic mobility shift assay, the triterpenoid suppressed nuclear factor-kappaB (NF-kappaB) activation induced by TNF and other inflammatory agents, and this correlated with the inhibition of IkappaBalpha phosphorylation and degradation, inhibition of IkappaB kinase complex (IKK) activation, suppression of p65 phosphorylation and nuclear translocation, and abrogation of NF-kappaB-dependent reporter activity. Overall, our results demonstrate that escin inhibits activation of NF-kappaB through inhibition of IKK, leading to down-regulation of NF-kappaB-regulated cell survival and metastatic gene products and thus resulting in sensitization of cells to cytokines and chemotherapeutic agents.
Harikumar
Kuzhuvelil B
KB
Department of Experimental Therapeutics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
Sung
Bokyung
B
Pandey
Manoj K
MK
Guha
Sushovan
S
Krishnan
Sunil
S
Aggarwal
Bharat B
BB
D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D017931:DNA Primers; D004928:Escin / Q000494:pharmacology*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D007680:Kidney Neoplasms / Q000196:embryology / Q000473:pathology; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000473:pathology; D016296:Mutagenesis; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000187:drug effects / Q000235:genetics; D009361:Neoplasm Invasiveness; D015398:Signal Transduction / Q000187:drug effects; D014158:Transcription, Genetic / Q000187:drug effects
D017304:Annexin A5; D017931:DNA Primers; D016328:NF-kappa B; D004928:Escin