Project description:KRAS-mutant pancreatic ductal adenocarcinoma (PDAC) is highly immunosuppressive and resistant to targeted therapies, immune checkpoint blockade and engineered T cells. In this study, we performed a systematic high throughput combinatorial drug screen and identified a synergistic interaction between the MEK inhibitor trametinib and the multi-kinase inhibitor nintedanib. Using bulk and single-cell RNA sequencing and immunophenotyping, we show that the combination therapy reprograms the immunosuppressive microenvironment and primes cytotoxic and memory T cells to infiltrate the tumors, thereby sensitizing mesenchymal PDAC to PD-L1 inhibition.
Project description:KRAS-mutant pancreatic ductal adenocarcinoma (PDAC) is highly immunosuppressive and resistant to targeted therapies, immune checkpoint blockade and engineered T cells. In this study, we performed a systematic high throughput combinatorial drug screen and identified a synergistic interaction between the MEK inhibitor trametinib and the multi- kinase inhibitor nintedanib. Using single cell RNA sequencing and immunophenotyping, we show that the combination therapy reprograms the immunosuppressive microenvironment and primes cytotoxic and memory T cells to infiltrate the tumors, thereby sensitizing mesenchymal PDAC to PD-L1 inhibition.
Project description:KRAS-mutant pancreatic ductal adenocarcinoma (PDAC) is highly immunosuppressive and resistant to targeted therapies, immune checkpoint blockade and engineered T cells. Here, we performed a systematic high throughput combinatorial drug screen and identified a synergistic interaction between the MEK inhibitor trametinib and the multi-kinase inhibitor nintedanib. This interaction targets KRAS-directed oncogenic signaling in the aggressive and therapy resistant non-glandular mesenchymal subtype of PDAC, driven by an allelic imbalance, increased gene-dosage and expression of oncogenic KRAS. Mechanistically, the combinatorial treatment induces cell cycle arrest and cell death and initiates an interferon response. Using single cell RNA sequencing and immunophenotyping, we show that the combination therapy reprograms the immunosuppressive microenvironment and primes cytotoxic and memory T cells to infiltrate the tumors, thereby sensitizing mesenchymal PDAC to PD-L1 inhibition. This work opens new avenues to target the therapy refractory mesenchymal PDAC subtype.
Project description:KRAS-mutant pancreatic ductal adenocarcinoma (PDAC) is highly immunosuppressive and resistant to targeted therapies, immune checkpoint blockade and engineered T cells. Here, we performed a systematic high throughput combinatorial drug screen and identified a synergistic interaction between the MEK inhibitor trametinib and the multi-kinase inhibitor nintedanib. This interaction targets KRAS-directed oncogenic signaling in the aggressive and therapy resistant non-glandular mesenchymal subtype of PDAC, driven by an allelic imbalance, increased gene-dosage and expression of oncogenic KRAS. Mechanistically, the combinatorial treatment induces cell cycle arrest and cell death and initiates an interferon response. Using single cell RNA sequencing and immunophenotyping, we show that the combination therapy reprograms the immunosuppressive microenvironment and primes cytotoxic and memory T cells to infiltrate the tumors, thereby sensitizing mesenchymal PDAC to PD-L1 inhibition. This work opens new avenues to target the therapy refractory mesenchymal PDAC subtype.
Project description:Interleukin-34 (IL-34) is an alternative ligand to colony-stimulating factor-1 (CSF-1) for the CSF-1 receptor that acts as a key regulator of monocyte/macrophage lineage. In this study, we show that cancer cells-derived IL-34 mediates resistance to immune checkpoint blockade regardless of CSF-1 existence. In a therapeutic study of a programmed death-1 and cytotoxic T-lymphocyte-associated antigen-4 blocking monoclonal antibody, the expression of IL-34 in tumors was accompanied with limited benefits compared to IL-34 non-expressing tumors in various murine cancer models. Consistent with its immunosuppressive characteristics, the expression of IL-34 in tumors correlates with decreased frequencies of cellular (such as CD8+ and CD4+ T cells) and molecular (including various cytokines and chemokines) effectors at the tumor microenvironment. In addition, IL-34 blockade expands the M1-macrophage population. Then, a neutralizing antibody against IL-34 helped to reverse these effects and improved the therapeutic effects of the immune checkpoint blockade in combinatorial therapeutic models, including a patient-derived xenograft model of primary lung adenocarcinoma. Collectively, we revealed that tumor-derived IL-34 inhibits the efficacy of immune checkpoint blockade and proposed the utility of IL-34 blockade as a new strategy for cancer therapy.
Project description:Brain tumors are typically immunosuppressive and refractory to immunotherapies for reasons that remain poorly understood. The unbiased profiling of immune cell types in the tumor microenvironment may reveal immunologic networks affecting therapy and course of disease. Here we identify and validate the presence of hematopoietic stem and progenitor cells (HSPCs) within tumor tissues that are positively linked to glioblastoma malignancy. In contrast to the medullary hematopoietic compartment, tumor-associated HSPCs are comprised of a majority of CD38- immature cells, such as hematopoietic stem cells and multipotent progenitors, express genes related to glioblastoma progression and display patterns of accelerated cell cycle. When cultured ex vivo, tumor-associated HSPCs form prevalently myeloid colonies, suggesting potential in situ myelopoiesis. In experimental models, HSPCs promote tumor cell proliferation, expression of the immune checkpoint PD-L1 and secretion of tumor promoting cytokines such as IL-6, IL-8 and CCL2, indicating concomitant support of both malignancy and immunosuppression. Additionally, the frequency of tumor-associated HSPCs is prognostic for patient survival and correlate with immunosuppressive phenotypes. These findings identify a new element in the complex landscape of glioblastoma that may serve as an independent prognostic factor or target for brain tumor immunotherapies.
Project description:Glioblastoma multiforme (GBM) is a non T cell-inflamed cancer characterized by an immunosuppressive microenvironment that impedes dendritic cell maturation and T cell cytotoxicity. The alleviation of immunosuppression might be a prerequisite for succesful immune checkpoint therapy in GBM. We here combine anti-angiogenic and immune checkpoint therapy and demonstrate improved therapeutic efficacy in syngeneic, orthotopic GBM models. We observed that blockade of vascular endothelial growth factor (VEGF), Angiopoietin-2 (Ang-2) and programmed cell death protein-1 (PD-1) significantly extended survival compared to vascular targeting alone. In the GBM microenvironment, triple therapy increased the numbers of cytotoxic T-lymphocytes that inversely correlated with myeloid-derived suppressor and regulatory T cells. Furthermore, transcriptomic analysis of GBM microvessels indicates a global vascular normalization that was highest after triple therapy. Our results propose a rationale to overcome limitations of VEGF monotherapy by integrating the synergistic effects of VEGF/Ang-2 and PD-1 blockade to reinforce anti-tumor immunity through a normalized vasculature.
Project description:MicroRNAs (miRNAs) are non-coding molecules involved in post-transcriptional gene regulation that have been shown to modulate tumor cell proliferation and apoptosis and to act as oncogenes or tumor-suppressor genes. Although miRNAs have been linked to tumor progression, the connection between tumor-mediated immune modulation and miRNAs has yet to be explored. Specifically, how the miRNA dysregulation affects the monocyte-derived glioblastoma-infiltrating macrophages, the most abundant immune cell population within the glioblastoma microenvironment, and their immune suppressive properties has not been evaluated to date. Here we managed to purify the glioblastoma-infiltrating macrophages from the tumor microenvironment and compared their miRNA expression profile with the matched peripheral monocytes from the peripheral blood of the same GBM patient as well as with healthy donors. Of note, several most down-regulated miRNA candidates revealed in this study, including miR-142-3p, were also known for their role in mediating tumor-associated immunosuppression. These results suggest a novel approach to identify miRNA immune therapeutics using a two-step process: 1) screen miRNA expression from tumor-associated immune cells relative to normal immune cell, and 2) select and prioritize potential candidates on the basis of binding to immunosuppressive pathways or mechanisms. In the study presented here, 12 samples, including peripheral monocyte samples from 4 healthy donors, peripheral monocytes from 4 GBM patients and matched tumor-infiltrating macrophages extracted from the glioblastoma microenvironment, were used to acquire the miRNA expression profiles of 1732 unique mature miRNA sequences via the Phalanx Human miRNA OneArray Microarray v3 Platform.