Casearin X exhibits cytotoxic effects in leukemia cells triggered by apoptosis.
Clerodane diterpenes have demonstrated cytotoxic, antiplasmodial and anti-ulcer properties. In the present work, we determined the cytotoxic effect of casearin L (Cas L), O (Cas O) and X (Cas X) and (-)-hardwickiic acid isolated from Casearia sylvestris leaves, and investigated the underlying mechanisms involved in in vitro cell death induced by Cas X in HL-60 leukemia cells (0.7, 1.5 and 3.0μM). Cytotoxicity tests demonstrated that Cas X was the most active compound studied, showing greater cytotoxic effects against CEM and HL-60 lines (IC(50) of 0.4μM) and human peripheral blood mononuclear cells (PBMC, IC(50) of 1.2μM). After 24h exposure, Cas X caused a decrease in 5-bromo-20-deoxyuridine (BrdU) incorporation (36.6 and 24.5% labeling at 0.7 and 1.5μM, respectively), reduction in viability, and increase in apoptotic and necrotic leukemia cells in a dose-dependent manner evidenced by the trypan blue and AO/EB (acridine orange/ethidium bromide) assays. Moreover, Cas X-treated cells exhibited nuclear fragmentation and cytoplasmic vacuolization depending on the concentration tested. These characteristics of apoptosis or secondary necrosis were confirmed by flow cytometry which revealed DNA fragmentation, phosphatidylserine externalization, activation of the effector caspases 3/7 and mitochondrial depolarization. We then found evidence that Cas X causes cell death via apoptotic pathways, corroborating the potential of casearins as compounds with promising antitumor-related properties.
Ferreira
Paulo M Pinheiro
PM
Universidade Federal do Piauí, 64.600-000 Picos, Piauí, Brazil.
Santos
André G
AG
Tininis
Aristeu G
AG
Costa
Patricia M
PM
Cavalheiro
Alberto J
AJ
Bolzani
Vanderlan S
VS
Moraes
Manoel O
MO
Costa-Lotufo
Letícia V
LV
Montenegro
Raquel C
RC
Pessoa
Cláudia
C
D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D004247:DNA / Q000096:biosynthesis / Q000235:genetics; D053938:DNA Fragmentation / Q000187:drug effects; D004224:Diterpenes / Q000494:pharmacology; D045785:Diterpenes, Clerodane / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D005434:Flow Cytometry; D018922:HL-60 Cells; D006801:Humans; D007938:Leukemia / Q000473:pathology*; D008928:Mitochondria / Q000187:drug effects; D010718:Phosphatidylserines / Q000378:metabolism
C548433:1-(acetyloxy)-3,5,6,6a,7,8,9,10-octahydro-10-hydroxy-7,8-dimethyl-7-(3-methylpenta-2,4-dien-1-yl)naphtho(1,8a-c)furan-3,5-diyl dibutanoate; D004224:Diterpenes; D045785:Diterpenes, Clerodane; D010718:Phosphatidylserines; C074343:hardwickic acid; D004247:DNA; D053148:Caspase 3; D053179:Caspase 7