Vántus T, Kéri G, Krivickiene Z, Valius M, Steták A, Keppens S, Csermely P, Bauer PI, Bökönyi G, Declercq W, Vandenabeele P, Merlevede W, Vandenheede JR. The somatostatin analogue TT-232 induces apoptosis in A431 cells: sustained activation of stress-activated kinases and inhibition of signalling to extracellular signal-regulated kinases.
Cell Signal 2001;
13:717-25. [PMID:
11602182 DOI:
10.1016/s0898-6568(01)00194-2]
[Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
TT-232 is a somatostatin analogue containing a five-residue ring structure. The present report describes TT-232-induced signalling events in A431 cells, where a 4-h preincubation with the peptide irreversibly induced a cell death program, which involves DNA-laddering and the appearance of shrunken nuclei, but is unrelated to somatostatin signalling. Early intracellular signals of TT-232 include a transient two-fold activation of the extracellular signal-regulated kinase (ERK2) and a strong and sustained activation of the stress-activated protein kinases c-Jun NH(2)-terminal kinase (JNK)/SAPK and p38MAPK. Blocking the signalling to ERK or p38MAPK activation had no effect on the TT-232-induced cell killing. At the commitment time for inducing cell death, TT-232 decreased EGFR-tyrosine phosphorylation and prevented epidermial growth factor (EGF)-induced events like cRaf-1 and ERK2 activation. Signalling to ERK activation by FCS, phorbol 12-myristate 13-acetate (PMA) and platelet-derived growth factor (PDGF) was similarly blocked. Our data suggest that TT-232 triggers an apoptotic type of cell death, concomitant with a strong activation of JNK and a blockade of cellular ERK2 activation pathways.
Collapse