Galectin-1 inhibitors and their potential therapeutic applications: a patent review

Introduction: Galectins have affinity for -galactosides. Human galectin-1 is ubiquitously expressed in the body and its expression level can be a marker in disease. Targeted inhibition of galectin-1 gives potential for treatment of inflammatory disorders and anti-cancer therapeutics. Areas covered: This review discusses progress in galectin-1 inhibitor discovery and development. Patent applications pertaining to galectin-1 inhibitors are categorised as monovalent- and multivalent-carbohydrate-based inhibitors, peptides- and peptidomimetics. Furthermore, the potential of galectin-1 protein as a therapeutic is discussed along with consideration of the unique challenges that galectin-1 presents, including its monomer-dimer equilibrium and oxidized and reduced forms, with regard to delivering an intact protein to a pathologically relevant site. Expert opinion: Significant evidence implicates galectin-1's involvement in cancer progression, inflammation, and host-pathogen interactions. Conserved sequence similarity of the carbohydrate-binding sites of different galectins makes design of specific antagonists (blocking agents/inhibitors of function) difficult. Key challenges pertaining to the therapeutic use of galectin-1 are its monomer-dimer equilibrium, its redox state, and delivery of intact galectin-1 to the desired site. Developing modified forms of galectin-1 has resulted in increased stability and functional potency. Gene and protein therapy approaches that deliver the protein toward the target are under exploration as is exploitation of different inhibitor scaffolds.