Figure 6.Activation of p53 by metabolic stress; effects of an AMPK inhibitor on p53 phosphorylation.(A) An AMPK inhibitor attenuates Ser20
site phosphorylation of p53 and p53 induction mediated by treatment with
AICAR. MOLT-3 cells were treated with (even-numbered lanes) or without
(odd-numbered lanes) 0.5mM AICAR for 24 hours after an initial 24-hour
pre-treatment with: increasing concentrations (2.5-20μM) of the AMPK
inhibitor Compound C (lanes 5-12), a DMSO solvent control (lanes 3-4), or a
culture medium control (lanes 1-2). Cell lysates were examined by Western
blotting with antibodies against the indicated proteins. (B) An AMPK
inhibitor does not attenuate Ser20 site phosphorylation of p53 nor p53
induction mediated by treatment with X-rays. MOLT-3 cells were treated with
(even-numbered lanes) or without (odd-numbered lanes) 6Gy X-ray and
cultured for 4 hours after an initial 44-hour pre-treatment with:
increasing concentrations (1.25-10μM) of the AMPK inhibitor Compound C
(lanes 5-12), a DMSO solvent control (lanes 3-4), or a culture medium
control (lanes 1-2). Cell lysates were examined by Western blotting with
antibodies against the indicated proteins. (C) A CK1
inhibitor does not attenuate Ser20 site phosphorylation of p53 nor p53
induction mediated by treatment with AICAR. MOLT-3 cells were treated with
(even-numbered lanes) or without (odd-numbered lanes) 0.5mM AICAR for 24
hours after an initial 24-hour pre-treatment with: increasing
concentrations (10-60μM) of the CK1 inhibitor D4476 (lanes 5-12), a
DMSO solvent control (lanes 3-4), or a culture medium control (lanes 1-2).
Cell lysates were examined by Western blotting with antibodies against the
indicated proteins. (D) An ATM inhibitor does not attenuate
Ser20 site phosphorylation of p53 nor p53 induction mediated by treatment
with AICAR. MOLT-3 cells were treated with (even-numbered lanes) or without
(odd-numbered lanes) 0.5mM AICAR for 24 hours after an initial 24-hour pre-treatment
with: increasing concentrations (1-10μM) of the ATM inhibitor KU-55933
(lanes 5-12), a DMSO solvent control (lanes 3-4), or a culture medium
control (lanes 1-2). Cell lysates were examined by Western blotting with
antibodies against the indicated proteins.
