Aplidin induces apoptosis in human cancer cells via glutathione depletion and sustained activation of the epidermal growth factor receptor, Src, JNK, and p38 MAPK.
We report that Aplidin, a novel antitumor agent of marine origin presently undergoing Phase II clinical trials, induced growth arrest and apoptosis in human MDA-MB-231 breast cancer cells at nanomolar concentrations. Aplidin induced a specific cellular stress response program, including sustained activation of the epidermal growth factor receptor (EGFR), the non-receptor protein-tyrosine kinase Src, and the serine/threonine kinases JNK and p38 MAPK. Aplidin-induced apoptosis was only partially blocked by the general caspase inhibitor benzyloxycarbonyl-VAD-fluoromethyl ketone and was also sensitive to AG1478 (an EGFR inhibitor), PP2 (an Src inhibitor), and SB203580 (an inhibitor of JNK and p38 MAPK) in MDA-MB-231 cells. Supporting a role for EGFR in Aplidin action, EGFR-deficient mouse embryo fibroblasts underwent apoptosis upon treatment more slowly than wild-type EGFR fibroblasts and also showed delayed JNK and reduced p38 MAPK activation. N-Acetylcysteine and ebselen (but not other antioxidants such as diphenyleneiodonium, Tiron, catalase, ascorbic acid, and vitamin E) reduced EGFR activation by Aplidin. N-Acetylcysteine and PP2 also partially inhibited JNK and p38 MAPK activation. The intracellular level of GSH affected Aplidin action; pretreatment of cells with GSH or N-acetylcysteine inhibited, whereas GSH depletion caused, hyperinduction of EGFR, Src, JNK, and p38 MAPK. Remarkably, Aplidin also induced apoptosis and activated EGFR, JNK, and p38 MAPK in two cell lines (A-498 and ACHN) derived from human renal cancer, a neoplasia that is highly refractory to chemotherapy. These data provide a molecular basis for the anticancer activity of Aplidin.
Cuadrado
Ana
A
Drug Discovery Department, PharmaMar S. A., Tres Cantos, E-28760 Madrid, Spain.
Garcia-Fernandez
Luis F
LF
Gonzalez
Laura
L
Suarez
Yajaira
Y
Losada
Alejandro
A
Alcaide
Victoria
V
Martinez
Teresa
T
Fernandez-Sousa
Jose Maria
JM
Sanchez-Puelles
Jose Maria
JM
Munoz
Alberto
A
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D047630:Depsipeptides; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D007680:Kidney Neoplasms / Q000378:metabolism; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010456:Peptides, Cyclic / Q000494:pharmacology*; D010766:Phosphorylation; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D017479:Receptors, Platelet-Derived Growth Factor / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases
D000970:Antineoplastic Agents; D047630:Depsipeptides; D004791:Enzyme Inhibitors; D010456:Peptides, Cyclic; D066246:ErbB Receptors; D017479:Receptors, Platelet-Derived Growth Factor; D016392:Proto-Oncogene Proteins pp60(c-src); D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D005978:Glutathione; C098980:plitidepsin