RecombiMAb anti-mouse PD-1 (CD279)

Immunotherapy has demonstrated potential in treating various malignant tumors, but its efficacy in pancreatic cancer (PC) remains limited, possibly due to the dense stromal components and immunosuppressive microenvironment of PC. Focal adhesion kinase (FAK), a non-receptor tyrosine kinase, plays a crucial role in the tumor microenvironment and intracellular signaling pathways. However, the specific role of FAK in the development and progression of PC, as well as its regulatory mechanisms on the tumor immune microenvironment (TIM), are still not fully understood. In this study, we analyzed single-cell sequencing datasets and clinical specimens to evaluate the role of FAK in the immune response of PC. We verified the impact of FAK alterations on CD8+ T cell infiltration using a co-culture system of patient-derived organoids (PDO) and immune cells. Additionally, mouse PC models and dual humanized models are established to investigate the in vivo function of FAK and the potential of its inhibitors for immunotherapy. Our results demonstrate that FAK is associated with the immunosuppressive microenvironment in PC. Inhibiting FAK enhances CD8+ T cell infiltration by promoting CXCL10 secretion in PC. Moreover, FAK inhibitors exhibit a synergistic anti-tumor effect when combined with immune checkpoint inhibitors. This study explores the potential of FAK as a therapeutic target, particularly its role in modulating TIM, thereby providing new research directions for the treatment of PC.

Given recent leverage of mesenchymal stromal cells (MSCs) as a potent vaccination platform, we investigated whether forced degradation of an expressed experimental antigen fused to small degron sequences could prime potent antitumoral responses. Retrovirally gene-engineered MSCs were evaluated for their in-vitro antigen presentation capacity, nature of generated peptide repertoire and therapeutic potency in syngeneic immunocompetent mice with pre-established solid T cell lymphoma. Despite lack of noticeable changes in gene expression, MSC-UBvR-OVA vaccination triggered potent T cell activation which can be attributable to the enriched cell surface presentation of OVA-derived peptides added to elevated mitochondrial reactive oxidative species (ROS) production, the latter being associated with efficient antigen processing. Where MSC-UBvR-OVA vaccination successfully controlled tumor growth in cancer-bearing mice, the effect is further enhanced using tranylcypromine-stimulated MSCs and anti-PD-1 combination. Such anti-tumoral response relies on efferocytosis by endogenous phagocytes. Altogether, UBvR facilitated forced antigen degradation represents a plausible modality for future development of tumor antigen-expressing MSC-based vaccine.

Mesenchymal stromal cells (MSCs) have been modified via genetic or pharmacological engineering into potent antigen-presenting cells-like capable of priming responding CD8 T cells. In this study, our screening of a variant library of Accum molecule revealed a molecule (A1) capable of eliciting antigen cross-presentation properties in MSCs. A1-reprogrammed MSCs (ARM) exhibited improved soluble antigen uptake and processing. Our comprehensive analysis, encompassing cross-presentation assays and molecular profiling, among other cellular investigations, elucidated A1's impact on endosomal escape, reactive oxygen species production, and cytokine secretion. By evaluating ARM-based cellular vaccine in mouse models of lymphoma and melanoma, we observe significant therapeutic potency, particularly in allogeneic setting and in combination with anti-PD-1 immune checkpoint inhibitor. Overall, this study introduces a strong target for developing an antigen-adaptable vaccination platform, capable of synergizing with immune checkpoint blockers to trigger tumor regression, supporting further investigation of ARMs as an effective and versatile anti-cancer vaccine.

The Accum™ technology was initially designed to enhance the bioaccumulation of a given molecule in target cells. It does so by triggering endosomal membrane damages allowing endocytosed products to enter the cytosol, escaping the harsh environmental cues of the endosomal lumen. In an attempt to minimize manufacturing hurdles associated with Accum™ conjugation, we tested whether free Accum™ admixed with antigens could lead to outcomes similar to those obtained with conjugated products. Surprisingly, unconjugated Accum™ was found to promote cell death in vitro, an observation further confirmed on various murine tumor cell lines (EL4, CT-26, B16, and 4 T1). At the molecular level, unconjugated Accum™ triggers the production of reactive oxygen species and elicits immunogenic cell death while retaining its innate ability to cause endosomal damages. When administered as a monotherapy to animals with pre-established EL4 T-cell lymphoma, Accum™ controlled tumor growth in a dose-dependent manner, and its therapeutic effect relies on CD4 and CD8 T cells. Although unconjugated Accum™ synergizes with various immune checkpoint inhibitors (anti-CTLA4, anti-PD-1, or anti-CD47) at controlling tumor growth, its therapeutic potency could not be further enhanced when combined with all three tested immune checkpoint inhibitors at once due to its dependency on a specific dosing regimen. In sum, we report in this study an unprecedented new function for unconjugated Accum™ as a novel anticancer molecule. These results could pave the path for a new line of investigation aimed at exploring the pro-killing properties of additional Accum™ variants as a mean to develop second-generation anticancer therapeutics.