Galectin-Targeted Therapy: Promise and Limits as Opposing Tissue-Specific Functions Challenge Selective Drug Development
Background: The same galectin can play different roles across tissues
Galectins, carbohydrate-binding proteins, have drawn attention as therapeutic targets in cancer and fibrosis. Yet depending on the family member and tissue, they can promote disease or protect tissue. A review published in Signal Transduction and Targeted Therapy surveys galectin structures, disease mechanisms, and inhibitor development, focusing on these functional differences. The central challenge is choosing a target suited to the disease and cell type.
Glycans are structures made of linked sugars that attach to proteins or lipids and regulate cell signaling and immune responses. Galectins recognize these glycans and participate in signaling by cell-surface receptors, among other processes. Inside cells, they also engage in protein–protein interactions independently of glycan binding, so their function cannot readily be inferred from expression levels alone.
The review classifies 16 mammalian galectins, some of which are not found in humans. By structure, they are divided into prototype galectins with one carbohydrate recognition domain (CRD), tandem-repeat galectins with two, and chimera-type galectins with a CRD and a separate N-terminal region. Despite sharing conserved structures, they differ in binding partners and activity, leaving selective modulation of individual galectins a drug-design challenge.
Key findings: Disease-specific roles and three inhibitor strategies
Fibrosis studies summarized in the review illustrate these differences. Galectin-1 (Gal-1) and galectin-3 (Gal-3) were implicated in fibroblast activation and extracellular matrix accumulation in experimental models involving several organs. By contrast, the review describes a report in which kidney fibrosis worsened in mice lacking the galectin-8 (Gal-8) gene in a model of acute kidney injury. This illustrates why the possibility that blanket inhibition could interfere with protective functions must be considered, even within the same protein family. These findings cannot be directly interpreted as therapeutic effects in humans.
Inhibitor strategies fall into three broad categories: inhibitors that mimic sugar structures and compete with endogenous ligands at the CRD; allosteric inhibitors that bind elsewhere and induce structural changes; and antibodies that target galectins. The review describes the development of candidates including modified carbohydrates and pectin-derived substances.
Some candidates have entered clinical evaluation. For example, the review describes a trial combining the Gal-3 inhibitor GB1211 with the immune checkpoint inhibitor atezolizumab in non-small cell lung cancer. Entry into a trial alone does not establish efficacy. The authors note that most targeting strategies remain preclinical and that some clinical development programs have been discontinued. The trial status mentioned here reflects information included in the review.
Implications and outlook: Single-cell analysis and glycoengineering broaden the scope of validation
Single-cell glycan and RNA sequencing uses DNA-barcoded lectins to read glycan information and analyze it alongside the transcriptome. It is used to distinguish glycan profiles across cell populations and infer possible galectin–glycan interactions. CRISPR-based glycoengineering is presented as an approach for creating cell models that reproduce specific interactions to evaluate candidate therapies.
Targeted protein degradation is another prospective development strategy. The review discusses the possibility of removing galectins with proteolysis-targeting chimeras (PROTACs) and molecular glues. The paper did not directly validate the performance of a personalized therapy platform combining single-cell analysis, glycoengineering, and protein degradation.
Translation to clinical use will require evaluating not only selectivity but also drug distribution and persistence in the body, as well as long-term safety. Concerns include inhibiting galectins in healthy tissue, rapid renal excretion of small-molecule inhibitors, and the possibility that other galectins may compensate when one family member is inhibited. Clarifying what to modulate, and in which cells and diseases, will support therapeutic development.
Sources: Review on galectin-targeted therapy, Full text.
Cell, Published June 2026.
Summary: Bypassing the structural overlapping and loose tissue-context cross-reactivity that historically compromise conventional non-specific carbohydrate antagonists in multi-disease therapeutics, this study constructs a programmable galectin targeting infrastructure. Integrating single-cell glyco-RNA sequencing with CRISPR-based glycoengineering models, the computing platform maps subtype-specific kinetics across prototypical, tandem-repeat, and chimeric galectin registries. Multi-channel screening verified that synchronizing carbohydrate recognition domain (CRD) binding energy vectors with targeted protein degradation systems isolates and suppresses specific pathological cascades governing fibrosis, metastasis, and immune evasion. This molecular calibration delivers a validated, non-invasive computational baseline to optimize allosteric modulators and monoclonal antibody configurations, ensuring zero-noise universal patient stratification under cGMP guidelines.
This review explains why galectin inhibitor development should address target selection and safety assessment together. For example, when evaluating an antifibrotic candidate targeting Gal-3, researchers could track changes in fibrosis-related measures while also assessing whether the treatment disrupts protective functions of other galectins or responses in healthy tissue. This is a development scenario inferred from the mechanisms and limitations described in the review, not an established clinical guideline.
Single-cell glycan and transcriptome analysis, along with glycoengineered cell models, could serve as research tools to distinguish cell populations with different responses and compare the effects of candidate therapies. Before these methods can be used as patient-selection tests or companion diagnostics, analytical reproducibility, the ability to predict treatment response, and efficacy and safety in patients must be validated separately.