Supplemental figures 1-10. Supplementary Figure S1. Cell viability assay with NAMPT inhibitors. Supplementary Figure S2. NAMPT inhibitor induces PD-L1 upregulation on alive cells. Supplementary Figure S3. NAMPT inhibitor induces PD-L1 upregulation. Supplementary Figure S4. Tumor PD-L1 upregulation after injection of coumarin6GMX1778 co-loaded microparticles. Supplementary Figure S5. NAMPT inhibitor-induced autophagy underlies an increase in PD-L1 mRNA and protein levels. Supplementary Figure S6. Impact of local treatment with GMX1778 microparticles on cells labeled with Arg1 and CD68 in murine glioblastoma. Supplementary Figure S7. NAMPT inhibitor decreases glioblastoma-associated macrophages. Supplementary Figure S8. PD-L1 immunohistochemistry (brown) of GL261 glioblastoma after treatment with blank micro-particles (MP), blank MP and anti-PD-1, GMX1778 MP, and combination of GMX1778 MP and anti-PD-1. Supplementary Figure S9. Immunoflurescence of GL261 glioblastoma after treatment with blank micro-particles, anti-PD-1, GMX1778 micro-particles, and combination. Supplementary Figure S10. GranzymeB immunohistochemistry (brown) of GL261 glioblastoma after treatment with blank micro-particles (MP), blank MP and anti-PD-1, GMX1778 MP, and combination of GMX1778 MP and anti-PD-1.
ARTICLE ABSTRACT
The aggressive primary brain tumor glioblastoma (GBM) is characterized by aberrant metabolism that fuels its malignant phenotype. Diverse genetic subtypes of malignant glioma are sensitive to selective inhibition of the NAD+ salvage pathway enzyme nicotinamide phosphoribosyltransferase (NAMPT). However, the potential impact of NAD+ depletion on the brain tumor microenvironment has not been elaborated. In addition, systemic toxicity of NAMPT inhibition remains a significant concern. Here we show that microparticle-mediated intratumoral delivery of NAMPT inhibitor GMX1778 induces specific immunologic changes in the tumor microenvironment of murine GBM, characterized by upregulation of immune checkpoint PD-L1, recruitment of CD3+, CD4+, and CD8+ T cells, and reduction of M2-polarized immunosuppressive macrophages. NAD+ depletion and autophagy induced by NAMPT inhibitors mediated the upregulation of PD-L1 transcripts and cell surface protein levels in GBM cells. NAMPT inhibitor modulation of the tumor immune microenvironment was therefore combined with PD-1 checkpoint blockade in vivo, significantly increasing the survival of GBM-bearing animals. Thus, the therapeutic impacts of NAMPT inhibition extended beyond neoplastic cells, shaping surrounding immune effectors. Microparticle delivery and release of NAMPT inhibitor at the tumor site offers a safe and robust means to alter an immune tumor microenvironment that could potentiate checkpoint immunotherapy for glioblastoma.
Microparticle-mediated local inhibition of NAMPT modulates the tumor immune microenvironment and acts cooperatively with anti-PD-1 checkpoint blockade, offering a combination immunotherapy strategy for the treatment of GBM.
