Selective Nanobody-Derived Minibodies Targeting Galectin-1 and -7 Reveal Non-Redundant Glyco-Immune Functions and Therapeutic Potential in Triple-Negative Breast Cancer.

Galectins (GALs) act as glyco-immune checkpoints that modulate tumor immunity, but their overlapping expression complicates functional dissection and targeted inhibition. Here, we explore the distinct molecular and immunological roles of GAL-1 and GAL-7, two GAL sover expressed in triple-negative breast cancer (TNBC), and describe the development of highly selective nanobody-derived minibodies (G1M1 and G7M8) that specifically target each protein. In TNBC cells, GAL-1 and GAL-7 induced different cytokine profiles: GAL-1 increased pro-tumor mediators such as G-CSF and VEGF-A, while GAL-7 promoted immunomodulatory cytokines, highlighting their nonredundant functions. In vivo, both G1M1 and G7M8 reduced pro-tumor cytokines and boosted antitumor immunity, either alone or combined with anti-PD-1 therapy. Notably, G1M1 alone achieved results comparable to anti-PD-1 therapy in limiting lung metastases, increasing CD4+ T-cell infiltration, and decreasing PD-1+ Tregs. These findings demonstrate that selective GAL blockade with engineered minibodies is a promising strategy to expand immunotherapy options in TNBC.