Blocking p38/ERK crosstalk affects colorectal cancer growth by inducing apoptosis in vitro and in preclinical mouse models

We recently demonstrated that p38 alpha is required to maintain colorectal cancer (CRC) metabolism, as its inhibition leads to FoxO3A activation, autophagy, cell death, and tumor growth reduction both in vitro and in vivo. Here we show that inhibition of p38 alpha is followed by TRAIL-mediated activation of caspase-8 and FoxO3A-dependent HER3 upregulation with consequent overactivation of the MEK-ERK1/2 survival pathway. p38 alpha and MEK combined inhibition specifically induces apoptosis by enabling TRAIL signaling propagation through t-Bid and caspase-3, and fosters cell death in CRC cells and preclinical mouse models. Current MEK1-directed pharmacological strategies could thus be exploited, in combination with p38 alpha inhibition, to develop new approaches for CRC treatment. (C) 2012 Elsevier Ireland Ltd. All rights reserved.