Discovery of small molecule inhibitors of the Wnt/β-catenin signaling pathway by targeting β-catenin/Tcf4 interactions

Abstract

The Wnt/β-catenin signaling pathway typically shows aberrant activation in various cancer cells, especially colorectal cancer cells. This signaling pathway regulates the expression of a variety of tumor-related proteins, including c-myc and cyclin D1, and plays essential roles in tumorigenesis and in the development of many cancers. Small molecules that block the interactions between β-catenin and Tcf4, a downstream stage of activation of the Wnt/β-catenin signaling pathway, could efficiently cut off this signal transduction and thereby act as a novel class of anticancer drugs. This paper reviews the currently reported inhibitors that target β-catenin/Tcf4 interactions, focusing on the discovery approaches taken in the design of these inhibitors and their bioactivities. A brief perspective is then shared on the future discovery and development of this class of inhibitors. Impact statement This mini-review summarized the current knowledge of inhibitors of interactions of beta-catenin/Tcf4 published to date according to their discovery approaches, and discussed their in vitro and in vivo activities, selectivities, and pharmacokinetic properties. Several reviews presently available now in this field describe modulators of the Wnt/beta-catenin pathway, but are generally focused on the bioactivities of these inhibitors. By contrast, this review focused on the drug discovery approaches taken in identifying these types of inhibitors and provided our perspective on further strategies for future drug discoveries. This review also integrated many recently published and important works on highly selective inhibitors as well as rational drug design. We believe that the findings and strategies summarized in this review have broad implications and will be of interest throughout the biochemical and pharmaceutical research community.

Keywords: Tcf4; Wnt/β-catenin signaling pathway; anticancer agents; protein–protein interactions; small molecule inhibitors; β-Catenin.

Figure 1

Wnt/β-catenin signaling pathway. (a) Inactive state (extracellular messenger Wnt is not involved); (b) Active state (Wnt is actively involved). (A color version of this figure is available in the online journal.)

Figure 2

A simplified diagram of β-catenin structure. The central armadillo repeats and several important motifs in N- and C-termini are shown. (A color version of this figure is available in the online journal.)

Scheme 1

Lead optimization of TMP-A-1.^,(A color version of this scheme is available in the online journal.)

Scheme 2

New derivatives designed in reference. Modified parts are marked in red. (A color version of this scheme is available in the online journal.)