Project description:Neuroblastoma (NB) is considered an immunologically cold tumor and is usually less responsive to immune checkpoint blockade (ICB). Tumor-associated macrophages (TAMs) are highly infiltrated in NB tumors and promote immune escape and resistance to ICB. Hence therapeutic strategies targeting immunosuppressive TAMs can improve responses to ICB in NB. We recently discovered that spleen tyrosine kinase (Syk) reprograms TAMs toward an immunostimulatory phenotype and enhances T-cell responses in the lung adenocarcinoma model. Here we investigated if Syk is an immune-oncology target in NB and tested whether a novel immunotherapeutic approach utilizing Syk inhibitor together with radiation and ICB could provide a durable antitumor immune response in an MYCN amplified murine model of NB. Myeloid Syk KO mice and syngeneic MYCN-amplified cell lines were used to elucidate the effect of myeloid Syk on the NB tumor microenvironment (TME). In addition, the effect of Syk inhibitor, R788, on anti-tumor immunity alone or combination with anti-PDL1 mAb and radiation was also determined in murine NB models. The underlying mechanism of action of this novel therapeutic combination was also investigated. Herein, we report that Syk is a marker of NB -associated macrophages and plays a crucial role in promoting immunosuppression in the NB TME. We found that the blockade of Syk in NB-bearing mice markedly impairs tumor growth. This effect is facilitated by macrophages that become immunogenic in the absence of Syk, skewing the suppressive TME towards immunostimulation and activating anti-tumor immune responses. Moreover, combining FDA-approved Syk inhibitor, R788 (fostamatinib) along with anti-PDL1 mAb provides a synergistic effect leading to complete tumor regression and durable anti-tumor immunity in mice bearing small tumors (50 mm3) but not larger tumors (250 mm3). However, combining radiation to R788 and anti-PDL1 mAb prolongs the survival of mice bearing large NB9464 tumors.

Project description:Using both global and conditional knockout mice, we demonstrated that the transcription factor Basic Helix-Loop-Helix Family Member E40 (BHLHE40/DEC1) is required in T cells for rejection of mouse syngeneic tumors upon immune checkpoint therapy (ICT) with anti-PD-1 or anti-CTLA-4 monoclonal antibody (mAb) treatment. Using single cell RNA sequencing (scRNAseq) we profiled intratumoral CD45+ cells from syngeneic mouse sarcomas that (a) grow progressively with control treatment in either Bhlhe40+/+ or Bhlhe40-/- tumor-bearing mice, (b) reject following anti-PD-1 or anti-CTLA-4 ICT in Bhlhe40+/+ tumor-bearing mice, or (c) grow progressively following anti-PD-1 or anti-CTLA-4 in Bhlhe40-/- mice. We performed two separate scRNAseq experiments with the same conditions but harvested tumors on either day 9 post-tumor transplant or day 11 post-tumor transplant. The groups were as follows: (1) Control mAb Bhlhe40+/+, (2) Control mAb Bhlhe40-/-, (3) anti-PD-1 Bhlhe40+/+, (4) anti-PD-1 Bhlhe40-/-, (5) anti-CTLA-4 Bhlhe40+/+, and (6) anti-CTLA-4 Bhlhe40-/-. scRNAseq of intratumoral immune cells in BHLHE40-deficient mice revealed differential ICT-induced immune cell remodeling. These BHLHE40-dependent gene expression alterations were associated with altered metabolism, NF-kB signaling, and IFN- response in subpopulations of intratumoral CD4+ and CD8+ T cells. Intratumoral T cells from tumor-bearing Bhlhe40-/- mice also had higher transcript expression of the inhibitory receptor gene Tigit, along with altered transcript expression of chemokine/chemokine receptor granzyme family members. Bhlhe40-/- CD4+ and CD8+ T cells also had reduced ICT-driven IFN- production. Furthermore, BHLHE40 was required for ICT-induced remodeling of macrophages from a CX3CR1+ CD206+ subpopulation to an iNOS+ subpopulation. While anti-PD-1 or anti-CTLA-4 ICT in tumor-bearing Bhlhe40-/- mice led to tumor outgrowth—several BHLHE40-dependent changes were specific to the ICT treatment that was administered.

Project description:Purpose: To compare cell states between control Her2-BBz and JUN-overexpression Her2-BBz human CAR T cells in a mouse model of osteosarcoma. Methods: 8-week old NSG mice were implanted with 1 million 143B osteosarcoma tumor cells intramuscularly in the right leg. 14 days post tumor implantation, mice were infused intravenously with 10 million human CAR+ T cells via tail vein injection. Before T cell transfer, mice were randomized for tumor size and treated with either control Her2-BBz or JUN-overexpressing Her2-BBz CAR T cells. T cells were 70% CAR+ at infusion for both groups. 14 days post T cell treatment (day 28 post tumor engraftment), 6 mice per group were euthanized, solid tumor tissue was collected, mechanically dissociated, and single cell suspensions were labeled with human-CD45 antibody and viability dye. Live hCD45+ tumor-infiltrating lymphocytes were sorted from each tumor and 6 samples were pooled for each group. ~35,000-40,000 sorted live cells (counted post sort) for each group were delivered to the Stanford Functional Genomics Facility for 3' single-cell RNA-sequencing on the 10X Genomics platform. Results: We found that substantially more JUN-overexpressing Her2-BBz CAR T cells were within the G2/M and S phases of the cell cycle than control Her2-BBz CAR T cells, consistent with increased in vivo proliferation of JUN-Her2-BBz CAR T cells. Furthermore, JUN-Her2-BBz CAR T cells also demonstrated a more activated transcriptional program (as measured by IL2RA and CD38), while many exhaustion-associated genes were downregulated (PDCD1, BTLA, TIGIT, CD200, ENTPD1, NR4A2) compared to control Her2-BBz CAR T cells. Finally, a small cluster of cells characterized by high IL7R expression (IL7R+ KLF2+ CD27+ TCF7+ SELL+) was apparent in JUN-overexpressing but not in control Her2-BBz CAR T cells, consistent with maintenance of a memory-like population capable of self-renewal. Conclusions: This study provides insights into cell states that could explain the improved efficacy of JUN-overexpression Her2-BBz CAR T cells compared to control Her2-BBz CAR T cells in a mouse model of osteosarcoma.

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Immune Restoring (IR) CAR-T Cells Display Superior Antitumor Activity and Reverse Immunosuppressive TME in a Humanized ccRCC Orthotopic Mouse Model

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