Aberrant activation of the Wnt signaling pathway has been identified in numerous types of cancer. One common feature of oncogenic Wnt regulation involves an increase in the cellular levels of β‐catenin due to interference with its constitutive ubiquitin‐dependent degradation. Targeting β‐catenin has therefore emerged as an appealing approach for the treatment of Wnt‐dependent cancers. Here, we report a strategy that employs multifunctional stapled peptides to recruit an E3 ubiquitin ligase to β‐catenin, thereby rescuing β‐catenin degradation by hijacking the endogenous ubiquitin‐proteasome pathway. Specifically, we designed, synthesized, and evaluated a panel of multifunctional stapled peptides that have a β‐catenin binding moiety (StAx‐35) covalently linked to a second stapled peptide moiety (SAH‐p53‐8), which is capable to interact with the E3 ubiquitin ligase MDM2. We found that in vitro these multifunctional peptides can recruit the MDM2 protein to β‐catenin and induce poly‐ubiquitination on β‐catenin. In cellulo, treatment of the human colorectal cancer cell line SW480 with the multifunctional stapled peptides showed dose‐dependent degradation of endogenous β‐catenin levels. In addition, a luciferase reporter assay showed that the multifunctional stapled peptides can suppress β‐catenin‐mediated gene expression via the Wnt signaling pathway. Therefore, these multifunctional stapled peptides provide a unique research tool for examining the Wnt signaling pathway by targeted knockdown of β‐catenin at the protein level, and may serve as leads for potential drug candidates in the treatment of Wnt‐dependent cancers.

A highly efficient synthesis of unsymmetrical 3,3’-diindolylmethanes bearing various substituents has been developed by palladium-catalyzed cascade Heck/cyclization reaction. In this transformation, precursors allenamides and o-ethynylanilines were utilized to generate in...

A selenium-catalyzed intramolecular oxidative amination of cyclopentenes has been described. A variety of 2-azabicyclo[2.2.1]heptenes were obtained with 58%-96% yields. This protocol was featured with mild reaction conditions and broad substrate scope. The subsequent modification of the bicyclic backbone and amino group further demonstrated the application value of this azabridged ring.