Wu, D.-S. | Search bioRxiv

bioRxiv2025

Modulating Glutamine Metabolism Reprograms Pro-Inflammatory Differentiation in Macrophages

Previous in vivo studies demonstrated that JHU083/DON, a glutamine analog drug, potently reprograms M1/M2 macrophages. To determine whether these effects are direct or indirect, we utilized an in vitro murine bone marrow-derived macrophage (BMDM) model, which recapitulates macrophage differentiation and polarization processes, to examine the impact of DON on the M1 macrophages. DON was applied during M1 differentiation or to fully polarized M1 macrophages, revealing that glutamine inhibition initially suppressed M1 activity but later enhanced it, resulting in sustained pro-inflammatory activation. Multi-omics analyses (bulk RNA-seq and LC-MS), time-course assays, and glutamine depletion experiments consistently suggested that prolonged glutamine inhibition elevates glutamine levels, which sustain pro-inflammatory gene transcription. In contrast, M2 and tumor-associated macrophages (TAM), which are immunosuppressive, were more susceptible to DON, leading to functional suppression. Collectively, our findings uncover stage-specific mechanisms by which glutamine inhibition modulates M1 polarization, offering a mechanistic rationale for therapeutic strategies that sustain pro-inflammatory, anti-tumor macrophage activity while concurrently suppressing immunosuppressive myeloid subsets in cancer.

cancer biology↗

bioRxiv2018

Inhibitor of the spindle assembly checkpoint surpasses apoptosis sensitizer in synergy with taxanes

The antitumor effect of taxanes have been attributed to their ability to induce mitotic arrest through activation of the spindle assembly checkpoint. Cell death following prolonged mitotic arrest is mediated by the intrinsic apoptosis pathway. Thus, apoptosis sensitizers which inhibit antiapoptotic Bcl-2 family proteins has been shown to enhance taxanes-induced cell death. By contrast, spindle checkpoint disruption facilitates mitotic slippage and is thought to promote taxanes resistance. Notably, other modes of cell death also contribute to treatment outcomes. Here we show that inhibition of the spindle checkpoint suppresses taxanes induced apoptosis but increases terminal growth arrest of tumor cells with features of cellular senescence. By using clonogenic assay which measures the net result of multiple forms of cell death and is more reflective of therapeutic response, our finding suggests apoptosis is not a major determinant of antitumor efficacy of taxanes, whereas spindle checkpoint inhibitor displays a long-term advantage over apoptosis sensitizer in blocking colony outgrowth of tumor cells when combined with different microtubule toxins, therefore represents a superior therapeutic strategy.\n\nSIGNIFICANCEApoptosis has long been regarded as the primary mechanism of anti-cancer efficacy of taxanes, while the role of the spindle assembly checkpoint (SAC) in treatment response to taxanes has been controversial. Either apoptosis sensitizer or inhibitor of SAC has been reported to synergize with taxanes. While inhibitor of antiapoptotic proteins potentiates taxanes induced apoptosis, inhibitor of SAC suppresses apoptosis by facilitating mitotic slippage, that is why it is implicated in taxanes resistance. By demonstrating that apoptotic rates are not associate with long-term treatment response, not only do we find that inhibitor of SAC displays a long-term advantage over apoptosis sensitizer in combination with taxanes, but we also resolve the dispute around the role of SAC in cellular response to taxanes.

cancer biology↗