1. The anti-promyelocytic leukemia mode of action of two endophytic secondary metabolites unveiled by a proteomic approach
- Author
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Margareth B. C. Gallo, Diego Menezes, Núbia Rocha, Billy W. Day, Fernanda Balem, Timothy S. Sturgeon, Miranda J. S. Falso, Mônica Tallarico Pupo, and Raghavan Balachandran
- Subjects
Aphidicolin ,Proteomics ,Programmed cell death ,Proteome ,Pharmaceutical Science ,Antineoplastic Agents ,HL-60 Cells ,Biology ,Asteraceae ,Microtubules ,Analytical Chemistry ,chemistry.chemical_compound ,Leukemia, Promyelocytic, Acute ,rho Guanine Nucleotide Dissociation Inhibitor beta ,Tubulin ,Ergosterol ,Drug Discovery ,Endophytes ,Humans ,Proteasome activator complex ,Mode of action ,Cytotoxicity ,Pharmacology ,Inflammation ,Biological Products ,Cell Death ,Organic Chemistry ,Fungi ,Cell Cycle Checkpoints ,Molecular biology ,Cell biology ,Mitochondria ,Thymosin beta-4 ,Gene Expression Regulation, Neoplastic ,Thymosin ,Oxidative Stress ,Complementary and alternative medicine ,chemistry ,14-3-3 Proteins ,Apoptosis ,Molecular Medicine ,METABOLISMO ,Growth inhibition - Abstract
As a result of a program to find antitumor compounds of endophytes from medicinal Asteraceae, the steroid (22E,24R)-8,14-epoxyergosta-4,22-diene-3,6-dione (a) and the diterpene aphidicolin (b) were isolated from the filamentous fungi Papulaspora immersa and Nigrospora sphaerica, respectively, and exhibited strong cytotoxicity against HL-60 cells. A proteomic approach was used in an attempt to identify the drugs' molecular targets and their respective antiproliferative mode of action. Results suggested that the (a) growth inhibition effect occurs by G2/M cell cycle arrest via reduction of tubulin alpha and beta isomers and 14-3-3 protein gamma expression, followed by a decrease of apoptotic and inflammatory proteins, culminating in mitochondrial oxidative damage that triggered autophagy-associated cell death. Moreover, the decrease observed in the expression levels of several types of histones indicated that (a) might be disarming oncogenic pathways via direct modulation of the epigenetic machinery. Effects on cell cycle progression and induction of apoptosis caused by (b) were confirmed. In addition, protein expression profiles also revealed that aphidicolin is able to influence microtubule dynamics, modulate proteasome activator complex expression, and control the inflammatory cascade through overexpression of thymosin beta 4, RhoGDI2, and 14-3-3 proteins. Transmission electron micrographs of (b)-treated cells unveiled dose-dependent morphological characteristics of autophagy- or oncosis-like cell death.
- Published
- 2014