Abstract
Wnt/β-catenin signaling is crucial both in normal embryonic development and throughout the life of an organism. Moreover, aberrant Wnt signaling has been associated with various diseases, especially cancer and fibrosis. Recent research suggests that direct targeting of the β-catenin/BCL9 protein–protein interaction (PPI) is a promising strategy to block the Wnt pathway. Progress in understanding the cocrystalline complex and mechanism of action of the β-catenin/BCL9 interaction facilitates the discovery process of its inhibitors, but only a few inhibitors have been reported. In this review, the discovery and development of β-catenin/BCL9 PPI inhibitors in the areas of drug design, structure–activity relationships and biological and biochemical properties are summarized. In addition, perspectives for the future development of β-catenin/BCL9 PPI inhibitors are explored.
Papers of special note have been highlighted as: • of interest; •• of considerable interest
References
- 1. . Inhibition of α-helix-mediated protein–protein interactions using designed molecules. Nat. Chem. 5(3), 161–173 (2013).
- 2. Estimating the size of the human interactome. Proc. Natl Acad. Sci. USA 105(19), 6959–6964 (2008).
- 3. An empirical framework for binary interactome mapping. Nat. Methods 6(1), 83–90 (2009).
- 4. . Druggable protein–protein interactions – from hot spots to hot segments. Curr. Opin. Chem. Biol. 17(6), 952–959 (2013).
- 5. . Principles of protein–protein interactions. Proc. Natl Acad. Sci. USA 93(1), 13–20 (1996).
- 6. . Modulators of protein–protein interactions. Chem. Rev., 114(9), 4695–4748 (2014).
- 7. From basic apoptosis discoveries to advanced selective BCL-2 family inhibitors. Nat. Rev. Drug. Discov. 16(4), 273–284 (2017).
- 8. Structure–activity relationship (SAR) of the α-amino acid residue of potent tetrahydroisoquinoline (THIQ)-derived LFA-1/ICAM-1 antagonists. Bioorg. Med. Chem. Lett. 21(1), 307–310 (2011).
- 9. . State-of-the-art strategies for targeting protein-protein interactions by small-molecule inhibitors. Chem. Soc. Rev. 44(22), 8238–8259 (2015). • Valuable article reporting the importance of PPIs.
- 10. . Updated research and applications of small molecule inhibitors of Keap1–Nrf2 protein–protein interaction: a review. Curr. Med. Chem. 21(16), 1861–1870 (2014).
- 11. . Aberrant Wnt signaling in multiple myeloma: molecular mechanisms and targeting options. Leukemia 33(5), 1063–1075 (2019).
- 12. . Nuclear regulation of Wnt/β-catenin signaling: it’s a complex situation. Genes 11(8),886 (2020).
- 13. . Carcinogenesis: a balance between beta-catenin and APC. Curr. Biol. 7(7), R443–R446 (1997).
- 14. . Binding of GSK3beta to the APC–beta-catenin complex and regulation of complex assembly. Science 272(5264), 1023–1026 (1996).
- 15. Wnt–β-catenin signalling in liver development, health and disease. Nat. Rev. Gastroenterol. Hepatol. 16(2), 121–136 (2019).
- 16. . Modulating the Wnt signaling pathway with small molecules. Protein Sci. 26(4), 650–661 (2017).
- 17. . Wnt signals across the plasma membrane to activate the beta-catenin pathway by forming oligomers containing its receptors, Frizzled and LRP. Development 131(20), 5103–5115 (2004).
- 18. The DIX domain of Dishevelled confers Wnt signaling by dynamic polymerization. Nat. Struct. Mol. Biol. 14(6), 484–492 (2007).
- 19. . Dishevelled: the hub of Wnt signaling. Cell. Signal. 22(5), 717–727 (2010).
- 20. . The Wnt signaling pathway in development and disease. Annu. Rev. Cell. Dev. Biol. 20, 781–810 (2004).
- 21. . Wnt/β-catenin signaling and disease. Cell 149(6), 1192–1205 (2012). •• A comprehensive introduction of the Wnt pathway and its related diseases.
- 22. Identification of c-MYC as a target of the APC pathway. Science 281(5382), 1509–1512 (1998).
- 23. . Beta-catenin simultaneously induces activation of the p53-p21WAF1 pathway and overexpression of cyclin D1 during squamous differentiation of endometrial carcinoma cells. Am. J. Pathol. 164(5), 1739–1749 (2004).
- 24. .The Bcl-w promoter is activated by beta-catenin/TCF4 in human colorectal carcinoma cells. Gene 432(1-2), 112–117 (2009).
- 25. Apc restoration promotes cellular differentiation and reestablishes crypt homeostasis in colorectal cancer. Cell 161(7), 1539–1552 (2015).
- 26. Beta-catenin, a novel prognostic marker for breast cancer: its roles in cyclin D1 expression and cancer progression. Proc. Natl Acad. Sci. USA 97(8), 4262–4266 (2000).
- 27. . Wnt signaling pathway in non-small cell lung cancer. J. Natl Cancer Inst. 106(1), djt356 (2014).
- 28. Somatic mutations of the beta-catenin gene are frequent in mouse and human hepatocellular carcinomas. Proc. Natl Acad. Sci. USA 95(15), 8847–8851 (1998).
- 29. . Wnt signaling strength regulates normal hematopoiesis and its deregulation is involved in leukemia development. Leukemia 26(3), 414–421 (2012).
- 30. Targeting the beta-catenin/TCF transcriptional complex in the treatment of multiple myeloma. Proc. Natl Acad. Sci. USA 104(18), 7516–7521 (2007).
- 31. . Initiation and execution mechanisms of necroptosis: an overview. Cell Death Differ. 24(7), 1184–1195 (2017).
- 32. Metastatic latency and immune evasion through autocrine inhibition of WNT. Cell 165(1), 45–60 (2016).
- 33. Genetic mechanisms of immune evasion in colorectal cancer. Cancer Discov. 8(6), 730–749 (2018).
- 34. Wnt/wingless signaling requires BCL9/legless-mediated recruitment of pygopus to the nuclear beta-catenin–TCF complex. Cell 109(1), 47–60 (2002).
- 35. . Discovery of selective small-molecule inhibitors for the β-catenin/T-cell factor protein–protein interaction through the optimization of the acyl hydrazone moiety. J. Med. Chem. 58(11), 4678–4692 (2015).
- 36. . Can we safely target the WNT pathway? Nat. Rev. Drug. Discov. 13(7), 513–532 (2014).
- 37. Pharmacological inhibition of β-catenin/BCL9 interaction overcomes resistance to immune checkpoint blockades by modulating T(reg) cells. Sci. Adv. 5(5), eaau5240 (2019).
- 38. . Wnt signaling and drug resistance in cancer. Mol. Pharmacol. 97(2), 72–89 (2020).
- 39. . Analysis of the interaction of BCL9 with beta-catenin and development of fluorescence polarization and surface plasmon resonance binding assays for this interaction. Biochemistry 48(40), 9534–9541 (2009).
- 40. Molecular cloning of translocation t(1;14)(q21;q32) defines a novel gene (BCL9) at chromosome 1q21. Blood 91(6), 1873–1881 (1998).
- 41. Low BCL9 expression inhibited ovarian epithelial malignant tumor progression by decreasing proliferation, migration, and increasing apoptosis to cancer cells. Cancer Cell Int. 19(1), 330 (2019).
- 42. . Drugging Wnt signalling in cancer. EMBO J. 31(12), 2737–2746 (2012).
- 43. Loss of BCL9/9l suppresses Wnt driven tumourigenesis in models that recapitulate human cancer. Nat. Commun. 10(1), 723 (2019).
- 44. . Bcl9 and Pygo synergise downstream of Apc to effect intestinal neoplasia in FAP mouse models. Nat. Commun. 10(1),724 (2019).
- 45. Hypoxia activates Wnt/β-catenin signaling by regulating the expression of BCL9 in human hepatocellular carcinoma. Sci. Rep. 7, 40446 (2017).
- 46. BCL9 promotes tumor progression by conferring enhanced proliferative, metastatic, and angiogenic properties to cancer cells. Cancer Res. 69(19), 7577–7586 (2009).
- 47. Bcl9/Bcl9l are critical for Wnt-mediated regulation of stem cell traits in colon epithelium and adenocarcinomas. Cancer Res. 70(16), 6619–6628 (2010).
- 48. . Crystal structure of a beta-catenin/BCL9/Tcf4 complex. Mol. Cell 24(2), 293–300 (2006). • Revealed the crystal structure of the β-catenin/BCL9 complex with moderate binding affinity and favorable binding area.
- 49. . The function of BCL9 in Wnt/beta-catenin signaling and colorectal cancer cells. BMC Cancer 8, 199 (2008).
- 50. . Identification and in vivo role of the Armadillo-Legless interaction. Development 131(17), 4393–4400 (2004).
- 51. . BCL9-2 binds Arm/beta-catenin in a Tyr142-independent manner and requires Pygopus for its function in Wg/Wnt signaling. Mech. Dev. 124(1), 59–67 (2007).
- 52. . Rational design of selective small-molecule inhibitors for β-catenin/B-cell lymphoma 9 protein–protein interactions. J. Am. Chem. Soc. 137(38), 12249–12260 (2015).
- 53. . Reaching for high-hanging fruit in drug discovery at protein–protein interfaces. Nature 450(7172), 1001–1009 (2007).
- 54. . Protein–protein interactions as druggable targets: recent technological advances. Curr. Opin. Pharmacol. 13(5), 791–796 (2013).
- 55. . Designing helical peptide inhibitors of protein–protein interactions. Curr. Opin. Struct. Biol. 39, 27–38 (2016).
- 56. . Modulating protein–protein interactions: the potential of peptides. Chem. Commun. (Camb.) 51(16), 3302–3315 (2015).
- 57. . Discovery and development of Kelch-like ECH-associated protein 1. nuclear factor erythroid 2-related factor 2 (KEAP1:NRF2) protein–protein interaction inhibitors: achievements, challenges, and future directions. J. Med. Chem. 59(24), 10837–10858 (2016).
- 58. . Highly efficient synthesis of covalently cross-linked peptide helices by ring-closing metathesis. Angew. Chem. Int. Ed. Engl. 37(23), 3281–3284 (1998).
- 59. . An all-hydrocarbon cross-linking system for enhancing the helicity and metabolic stability of peptides. J. Am. Chem. Soc. 122(24), 5891–5892 (2000).
- 60. . Hydrocarbon stapled peptides as modulators of biological function. ACS Chem. Biol. 10(6), 1362–1375 (2015).
- 61. . Peptide-based inhibitors of protein–protein interactions. ACS Chem. Biol. 26(3), 707–713 (2016).
- 62. . Hydrocarbon-stapled peptides: principles, practice, and progress. J. Med. Chem. 57(15), 6275–6288 (2014).
- 63. Stapled α-helical peptide drug development: a potent dual inhibitor of MDM2 and MDMX for p53-dependent cancer therapy. Proc. Natl Acad. Sci. USA 110(36), E3445–E3454 (2013).
- 64. . Design of triazole-stapled BCL9 α-helical peptides to target the β-catenin/B-cell CLL/lymphoma 9 (BCL9) protein–protein interaction. J. Med. Chem. 55(3), 1137–1146 (2012).
- 65. Targeted disruption of the BCL9/β-catenin complex inhibits oncogenic Wnt signaling. Sci. Transl. Med. 4(148), 148ra117 (2012).
- 66. . Vinylphosphonites for Staudinger-induced chemoselective peptide cyclization and functionalization. Chem. Sci. 10(25), 6322–6329 (2019).
- 67. . Synthetic mimetics of protein secondary structure domains. Philos. Trans. A Math. Phys. Eng. Sci. 368(1914), 989–1008 (2010).
- 68. Inhibition of β-catenin/B cell lymphoma 9 protein–protein interaction using α-helix-mimicking sulfono-γ-AApeptide inhibitors. Proc. Natl Acad. Sci. USA 116(22), 10757–10762 (2019).
- 69. . Hot spots – a review of the protein–protein interface determinant amino-acid residues. Proteins 68(4), 803–812 (2007).
- 70. . A hot spot of binding energy in a hormone–receptor interface. Science 267(5196), 383–386 (1995).
- 71. . The molecular architecture of protein–protein binding sites. Curr. Opin. Struct. Biol. 17(1), 67–76 (2007).
- 72. . Structure-based design of 1,4-dibenzoylpiperazines as β-catenin/B-cell lymphoma 9 protein–protein interaction inhibitors. ACS Med. Chem. Lett. 7(5), 508–513 (2016).
- 73. . Structure-based optimization of small-molecule inhibitors for the β-catenin/B-cell lymphoma 9 protein–protein interaction. J. Med. Chem. 61(7), 2989–3007 (2018).
- 74. An intrinsically labile α-helix abutting the BCL9-binding site of β-catenin is required for its inhibition by carnosic acid. Nat. Commun. 3, 680 (2012).
- 75. . Chemistry: chemical con artists foil drug discovery. Nature 513(7519), 481–483 (2014).
- 76. . Assessment of helical interfaces in protein–protein interactions. Mol. Biosyst. 5(9), 924–926 (2009).
- 77. . New substructure filters for removal of pan assay interference compounds (PAINS) from screening libraries and for their exclusion in bioassays. J. Med. Chem. 53(7), 2719–2740 (2010).
- 78. Molecular characterization of novel and selective peroxisome proliferator-activated receptor alpha agonists with robust hypolipidemic activity in vivo. Mol. Pharmacol. 75(2), 296–306 (2009).
- 79. . AlphaScreen selectivity assay for β-catenin/B-cell lymphoma 9 inhibitors. Anal. Biochem. 469, 43–53 (2015).
- 80. . Protein–protein interaction inhibitors get into the groove. Nat. Rev. Drug. Discov. 11(3), 173–175 (2012).
- 81. . Direct targeting of β-catenin in the Wnt signaling pathway: current progress and perspectives. Med. Res. Rev.
doi:10.1002/med.21787 (2021) (Epub ahead of print).