InVivoMAb mouse IgG2c isotype control, anti-dengue virus

Recent studies have highlighted the therapeutic potential of targeting tumor neoantigens in solid tumors; however, its efficacy in breast cancer remains unclear. Here, we evaluate the impact of tumor neoantigen-targeted strategies in a syngeneic mouse mammary carcinoma model. Mice previously exposed to 4T1 tumor cells (PETCs) or treated with tumor cell-derived lysates (TdLs) exhibited robust antitumor immunity, leading to reduced tumor growth and metastasis through tumor immune microenvironment remodeling. TdL administration in mice harboring orthotopic tumors significantly enhanced the efficacy of immune checkpoint blockade, suggesting its potential as an immunotherapeutic adjuvant. To further optimize neoantigen-based approaches, we developed a lipid nanoparticle (LNP)-based delivery system for neoantigen peptides, which effectively suppressed tumor progression and metastasis in vivo. Mechanistically, this strategy promoted antigen-specific T cell activation and reshaped the tumor immune landscape, enhancing immune-mediated tumor rejection. These findings underscore the therapeutic promise of personalized tumor neoantigen-targeted immunotherapy in breast cancer and support its further evaluation in clinical settings.

Laminin comprises α/β/γ subunits and performs tissue-specific functions that control cellular behavior. Laminin-α2 chains are highly expressed in neural components such as glial and Schwann cells and in muscles. Macrophages play important roles in tissue homeostasis and repair, and laminins affect macrophage dynamics. Integrin α7, a transmembrane receptor crucial for regulating cell-matrix interactions, has a high affinity for laminin-α2, but its function in macrophages remains unknown. Here, we find that loss of integrin α7 signaling induces a dendritic cell (DC)-like phenotype in THP-1-derived macrophages and in primary monocytes-derived macrophages induced by granulocyte macrophage colony-stimulating factor cultured on laminin-α2 chains. Functional blocking of integrin α7 induced dendritic processes of THP-1-derived macrophages. Gene expression analysis revealed DC markers and costimulatory molecules, and coculture experiments demonstrated that the DC-like cells could stimulate T cell proliferation. Functional inhibition of integrin α7 decreased PI3K-p85α levels and activated PI3K, thereby activating AKT. Monocyte-derived macrophages cultured on laminin α2 chains decreased integrin α7 expression, exhibited dendritic-like morphology, and increased expression of DC markers and costimulatory molecules. These findings suggest that, besides the established influence of cytokine milieu, DC differentiation is regulated by laminin α2/integrin α7-mediated cell adhesion. Integrin α7 has been a therapeutic target in tumors, and antibody-based integrin α7 neutralization can be clinically useful. The results of this study suggest implications for integrin α7 and laminin-α2 chains in DC immunotherapy.

The treatment of hepatocellular carcinoma (HCC) has been transformed by the use of immune checkpoint inhibitors. However, most patients with HCC do not benefit from treatment with immunotherapy. There is an urgent need to understand the mechanisms that underlie response or resistance to immunotherapy for patients with HCC. The use of syngeneic mouse models that closely recapitulate the heterogeneity of human HCC will provide opportunities to examine the complex interactions between cancer cells and nonmalignant cells in the tumor microenvironment.

Clonal myeloproliferation and development of bone marrow (BM) fibrosis are the major pathogenetic events in myelofibrosis (MF). The identification of novel antifibrotic strategies is of utmost importance since the effectiveness of current therapies in reverting BM fibrosis is debated. We previously demonstrated that osteopontin (OPN) has a profibrotic role in MF by promoting mesenchymal stromal cells proliferation and collagen production. Moreover, increased plasma OPN correlated with higher BM fibrosis grade and inferior overall survival in MF patients. To understand whether OPN is a druggable target in MF, we assessed putative inhibitors of OPN expression in vitro and identified ERK1/2 as a major regulator of OPN production. Increased OPN plasma levels were associated with BM fibrosis development in the Romiplostim-induced MF mouse model. Moreover, ERK1/2 inhibition led to a remarkable reduction of OPN production and BM fibrosis in Romiplostim-treated mice. Strikingly, the antifibrotic effect of ERK1/2 inhibition can be mainly ascribed to the reduced OPN production since it could be recapitulated through the administration of anti-OPN neutralizing antibody. Our results demonstrate that OPN is a novel druggable target in MF and pave the way to antifibrotic therapies based on the inhibition of ERK1/2-driven OPN production or the neutralization of OPN activity.

Plasma cell responses are associated with anti-tumor immunity and favorable response to immunotherapy. B cells can amplify anti-tumor immune responses through antibody production; yet B cells in patients and tumor-bearing mice often fail to support this effector function. We identify dysregulated transcriptional program in B cells that disrupts differentiation of naive B cells into anti-tumor plasma cells. The signaling network contributing to this dysfunction is driven by interleukin (IL) 35 stimulation of a STAT3-PAX5 complex that upregulates the transcriptional regulator BCL6 in naive B cells. Transient inhibition of BCL6 in tumor-educated naive B cells is sufficient to reverse the dysfunction in B cell differentiation, stimulating the intra-tumoral accumulation of plasma cells and effector T cells and rendering pancreatic tumors sensitive to anti-programmed cell death protein 1 (PD-1) blockade. Our findings argue that B cell effector dysfunction in cancer can be due to an active systemic suppression program that can be targeted to synergize with T cell-directed immunotherapy.