Fig 2: Either CD4+ T cell or CD8+ T cell depletion impaired the antitumor effects of combination therapy.A, B Representative bioluminescence images of K7M2 tumors at day 28 post treatment initiation (n = 6), tumor burdens were evaluated by total flux. C Kaplan–Meier curves showing survival of tumor-bearing mice treated with DMSO, anti-PD-1 antibody, combination therapy, and combination therapy plus T cell depletion. D Schematic model showing how c-Myc inhibitor reprograms tumor immune microenvironment in osteosarcoma. On the one hand, JQ-1 can promote T cell trafficking into tumors by increasing the expression and secretion of T cell-recruiting chemokines. On the other hand, JQ-1 is capable of facilitating crosstalk between antigen-presenting dendritic cells and T cells through the CD40/CD40L costimulatory pathway, leading to activation of tumor-specific CTLs.

Fig 3: Treatment with JQ-1 increases T cell infiltration and upregulates CD40/CD40L expression in K7M2 tumor.A Representative immunohistochemical images of CD4, CD8a, CD40, CD40L in K7M2 tumors, treated with JQ-1 or DMSO (400×, scale bar: 100 µm). B Positive signals were counted in four randomly selected fields (400×) in each tumor section using ImageJ, n = 6. C, D Representative histogram showing CD40 expression on dendritic cells (CD45 + CD11c + MHC-II+), macrophages (CD45 + CD11b + F4/80+) and B cells (CD45 + CD3-CD11c-B220+). E, F Histogram overlay showing CD40 ligand expression on CD4+ T cells and CD8+ T cells. G Representative Pseudo-color plots of IFN-? expression in CD4+ T cells and CD8+ T cell cells. H, I Representative histogram overlay showing IL2Ra expression on CD4+ T cells or CD8+ T cells.

Fig 4: JQ-1 represses tumor growth and alters the tumor immune microenvironment in the K7M2 model.A Bioluminescence of K7M2 tumor after confirmation of tumor formation, tumor progression was monitored weekly. B Tumor burden was evaluated by total flux, n = 6. C Representative immunohistochemical staining of c-myc in K7M2 tumors, scale bar: 100 µm. D Western blot analysis of the levels of c-myc in K7M2 tumors, treated or untreated with JQ-1. E Kaplan–Meier curves showing the survival time of mice in (A). F Heat map showing the gene expression profile of differentially expressed genes based on their hierarchical clustering. Cd40 and several T cell-recruiting chemokines significantly upregulated in JQ-1 treated group are highlighted. G Significantly different terms in GO analysis.