Kinetics of ERK1/2 activation determine sensitivity of acute myeloid leukaemia cells to the induction of apoptosis by the novel small molecule ingenol 3-angelate (PEP005).

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The novel small molecule ingenol 3-angelate (PEP005) has been shown previously to induce apoptosis in leukaemic cell lines and primary AML cells, an effect that requires the expression of protein kinase C-delta (PKCdelta). Here we have investigated signalling events downstream of PKCdelta that determine sensitivity of AML cells to PEP005. We show that activation of ERK1/2 MAP kinase occurred in both sensitive and resistant cells and that induction of apoptosis required sustained signalling through the ERK1/2 pathway. Inhibition of ERK1/2 signalling using the MEK inhibitor PD98059 inhibited PEP005-induced apoptosis and activation of ERK1/2 was shown to occur downstream of PKC activation. The data show that PEP005-induced apoptosis is both PKC and ERK1/2 dependent and indicate that chronic activation of ERK1/2 in leukaemic cells delivers a pro-apoptotic rather than a proliferative or survival signal.


Original languageEnglish
Pages (from-to)946-955
Number of pages10
Issue number8
Publication statusPublished - 14 May 2010


  • Apoptosis, ERK1/2, PKC, Acute myeloid leukaemia