A small molecule, (E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) phenol suppresses tumor growth via inhibition of IkappaB kinase β in colorectal cancer in vivo and in vitro

Here we report that a novel synthesized compound (E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) phenol (MMPP) which exhibits better stability, drug-likeness and anti-cancer effect than (E)-2,4-bis(p-hydroxyphenyl)-2-butenal (BHPB) that we previously reported. Of all newly synthesized BHPB analogues, MMPP showed the most significant inhibitory effect on colon cancer cell growth. Thus, we evaluated the anti-cancer effects and possible mechanisms of MMPP in vitro and in vivo. MMPP treatment (0-15 mu g/mL) induced apoptotic cell death and enhanced the expression of cleaved caspase-3 and cleaved caspase-8 in a concentration dependent manner. Notably, the expression of death receptor (DR) 5 and DR6 was significantly increased by MMPP treatment. Moreover, DR5 siRNA or DR6 siRNA transfection partially abolished MMPP-induced cell growth inhibition. Pull down assay and docking experiment showed that MMPP bound directly to IkappaB kinase beta (IKK beta). It was noteworthy that IKK beta mutant (C99S) partially abolished MMPP-induced cell growth inhibition and enhanced expression of DR5 and DR6. In addition, MMPP enhanced TRAIL-induced apoptosis, cell growth inhibition and expression of DRs. In xenograft mice model, MMPP (2.5-5 mg/kg) suppressed tumor growth in a dose dependent manner. Immunohistochemistry analysis showed that the expression levels of DR5 and DR6 and active caspase-3 were increased while the expression levels of PCNA and p-IKK beta were decreased in a dose dependent manner. Thus, MMPP may be a promising anti-cancer agent in colon cancer treatment.