Galectin-3 (Gal-3) Inhibitors as Radiosensitizers for Prostate Cancer

Introduction: Radioresistance in prostate cancer (PCa) poses a major therapeutic challenge. Galectin-3 (Gal-3) is overexpressed in aggressive PCa and may contribute to resistance mechanisms. This study evaluated the role of Gal-3 in radioresistance and assessed the effect of its pharmacological inhibition using GB1107. Methods: Parental (22RV1-P) and radioresistant (22RV1-RR) PCa cell lines were treated with GB1107. Western blotting assessed Gal-3 and Protein Phosphatase 1 alpha (PP1α) expression. Cell viability (PrestoBlue™), migration (wound assay), and clonogenic survival post-irradiation were evaluated. Statistical significance was set at p < 0.05. Results: Gal-3 was significantly upregulated in 22RV1-RR cells (p = 0.0237). GB1107 reduced viability and impaired migration in both cell lines. Radiosensitisation was observed in 22RV1-P cells (p < 0.0001) but was not significant in 22RV1-RR cells (p = 0.1258). A non-significant increase in PP1α expression was detected in RR cells. Conclusion: Gal-3 contributes to radioresistance. Further studies are needed to clarify the role of PP1α and optimise Gal-3-targeted strategies.