Reevaluating the senolytic activity of a GLS1 inhibitor and an anti-PD-1 antibody: toward greater reproducibility and methodological rigor

Abstract The discovery of the senescence-associated secretory phenotype (SASP) has reshaped our understanding of cellular senescence, shifting its role from a solely tumor-suppressive mechanism to a potential driver of chronic inflammation and age-related diseases. Accordingly, senolytic drugs, which selectively eliminate senescent cells, have garnered considerable interest due to promising preclinical studies. However, concerns remain regarding the reproducibility and generalizability of these findings. In this cross-laboratory study, we rigorously tested the senolytic efficacy of a GLS1 inhibitor and an anti-PD-1 antibody—agents previously reported to reduce the burden of p16 INK4a -positive senescent cells and improve health outcomes in aged mice. Contrary to earlier reports, our study demonstrates that neither GLS1 inhibition nor PD-1 blockade significantly reduced p16 INK4a -positive cell burden or improved aging-related health parameters. Although we do not seek to discredit prior work, our results underscore the need for rigorous design, standardized protocols, and independent validation to ensure reliable senolytics before clinical translation.