Constitutively Activated DAP12 Induces Functional Anti-Tumor Activation and Maturation of Human Monocyte-Derived DC

Exploratory Research for HIF-1α Overexpression Tumor Antigen in the Activation of Dendritic Cells and the Potent Anti-Tumor Immune Response

Background

Tumor-specific antigens play an important role in dendritic cell (DC)-based immunotherapy. The acquisition of tumor-specific antigens, which are essential for DC-based immunotherapy, poses a significant challenge. This study aimed to explore the efficacy of hypoxia inducible factor-1α (HIF-1α) overexpression tumor antigens in DC-based immunotherapy.

Methods

An HIF-1α over-expression cell line was constructed to prepare HIF-1α overexpression tumor antigens. The expression of CD14, CD40, CD80, CD86, and HLA-DR on the surface of dendritic cells derived from monocytes was assessed using flow cytometry after stimulation with tumor antigens enriched in HIF-1α. T cell proliferation was analyzed by CFSE division following incubation with mature DCs. The apoptotic tumor cells were detected through annexin V/PI staining following coculture with dendritic cells (DCs) stimulated by HIF-1α enriched antigens. The detection of damage-associated molecular pattern molecules (DAMPs) HMGB1 and calreticulin (CALR) was performed using Western blotting.

Results

The results demonstrated that HIF-1α-enriched tumor antigens significantly upregulated the expression of CD40, CD80, CD86, and HLA-DR in DCs compared to normal tumor antigens. Furthermore, co-incubation with HIF-1α-enriched tumor antigen-activated DCs enhanced T cell proliferation and stimulated the T cell-mediated cytotoxicity. Notably, the expression of DAMPs, such as HMGB1 and CALR, was elevated in HIF-1α-enriched tumor antigens.

Conclusion

Our findings demonstrate that tumor antigens enriched with HIF-1α may encompass tumor-specific antigens capable of stimulating DC activation, thereby enhancing T cell proliferation and cytotoxicity. These results provide support for the further advancement of HIF-1α enriched tumor antigens in preclinical and clinical investigations pertaining to tumor treatment.

The Potential of Siglecs and Sialic Acids as Biomarkers and Therapeutic Targets in Tumor Immunotherapy

The dysregulation of sialic acid is closely associated with oncogenesis and tumor progression. Most tumor cells exhibit sialic acid upregulation. Sialic acid-binding immunoglobulin-like lectins (Siglecs) are receptors that recognize sialic acid and are expressed in various immune cells. The activity of Siglecs in the tumor microenvironment promotes immune escape, mirroring the mechanisms of the well-characterized PD-1/PD-L1 pathway in cancer. Cancer cells utilize sialic acid-linked glycans to evade immune surveillance. As Siglecs exhibit similar mechanisms as the established immune checkpoint inhibitors (ICIs), they are potential therapeutic targets for different forms of cancer, especially ICI-resistant malignancies. Additionally, the upregulation of sialic acid serves as a potential tumor biomarker. This review examines the feasibility of using sialic acid and Siglecs for early malignant tumor detection and discusses the potential of targeting Siglec-sialic acid interaction as a novel cancer therapeutic strategy.

Combinatorial Immunotherapy with Agonistic CD40 Activates Dendritic Cells to Express IL12 and Overcomes PD-1 Resistance

Checkpoint inhibitors have revolutionized cancer treatment, but resistance remains a significant clinical challenge. Myeloid cells within the tumor microenvironment can modulate checkpoint resistance by either supporting or suppressing adaptive immune responses. Using an anti-PD-1-resistant mouse melanoma model, we show that targeting the myeloid compartment via CD40 activation and CSF1R blockade in combination with anti-PD-1 results in complete tumor regression in a majority of mice. This triple therapy combination was primarily CD40 agonist-driven in the first 24 hours after therapy and showed a similar systemic cytokine profile in human patients as was seen in mice. Functional single-cell cytokine secretion profiling of dendritic cells (DC) using a novel microwell assay identified a CCL22+CCL5+ IL12-secreting DC subset as important early-stage effectors of triple therapy. CD4+ and CD8+ T cells are both critical effectors of treatment, and systems analysis of single-cell RNA sequencing data supported a role for DC-secreted IL12 in priming T-cell activation and recruitment. Finally, we showed that treatment with a novel IL12 mRNA therapeutic alone was sufficient to overcome PD-1 resistance and cause tumor regression. Overall, we conclude that combining myeloid-based innate immune activation and enhancement of adaptive immunity is a viable strategy to overcome anti-PD-1 resistance.

Integrated analysis of C3AR1 and CD163 associated with immune infiltration in intracranial aneurysms pathogenesis

Background

To identify potential immune-related biomarkers, molecular mechanism, and therapeutic agents of intracranial aneurysms (IAs).

Methods

We identified the differentially expressed genes (DEGs) between IAs and control samples from GSE75436, GSE26969, GSE6551, and GSE13353 datasets. We used weighted gene co-expression network analysis (WGCNA) and protein-protein interaction (PPI) analysis to identify immune-related hub genes. We evaluated the expression of hub genes by using qRT-PCR analysis. Using miRNet, NetworkAnalyst, and DGIdb databases, we analyzed the regulatory networks and potential therapeutic agents targeting hub genes. Least absolute shrinkage and selection operator (LASSO) logistic regression was performed to identify optimal biomarkers among hub genes. The diagnostic value was validated by external GSE15629 dataset.

Results

We identified 227 DEGs and 22 differentially infiltrating immune cells between IAs and control samples from GSE75436, GSE26969, GSE6551, and GSE13353 datasets. We further identified 41 differentially expressed immune-related genes (DEIRGs), which were primarily enriched in the chemokine-mediated signaling pathway, myeloid leukocyte migration, endocytic vesicle membrane, chemokine receptor binding, chemokine activity, and viral protein interactions with cytokines and their receptors. Among 41 DEIRGs, 10 hub genes including C3AR1, CD163, CCL4, CXCL8, CCL3, TLR2, TYROBP, C1QB, FCGR3A, and FCGR1A were identified with good diagnostic values (AUC >0.7). Hsa-mir-27a-3p and transcription factors, including YY1 and GATA2, were identified the primary regulators of hub genes. 92 potential therapeutic agents targeting hub genes were predicted. C3AR1 and CD163 were finally identified as the best diagnostic biomarkers using LASSO logistic regression (AUC = 0.994). The diagnostic value of C3AR1 and CD163 was validated by the external GSE15629 dataset (AUC = 0.914).

Conclusions

This study revealed the importance of C3AR1 and CD163 in immune infiltration in IAs pathogenesis. Our finding provided a valuable reference for subsequent research on the potential targets for molecular mechanisms and intervention of IAs.

Ex Vivo Generation of CAR Macrophages from Hematopoietic Stem and Progenitor Cells for Use in Cancer Therapy

Chimeric antigen receptor (CAR) T-cell therapies have shown impressive results in patients with hematological malignancies; however, little success has been achieved in the treatment of solid tumors. Recently, macrophages (MΦs) were identified as an additional candidate for the CAR approach, and initial proof of concept studies using peripheral blood-derived monocytes showed antigen-redirected activation of CAR MΦs. However, some patients may not be suitable for monocyte-apheresis, and prior cancer treatment regimens may negatively affect immune cell number and functionality. To address this problem, we here introduce primary human hematopoietic stem and progenitor cells (HSPCs) as a cell source to generate functional CAR MΦs ex vivo. Our data showed successful CAR expression in cord blood (CB)-derived HSPCs, with considerable cell expansion during differentiation to CAR MΦs. HSPC-derived MΦs showed typical MΦ morphology, phenotype, and basic anti-bacterial functionality. CAR MΦs targeting the carcinoembryonic antigen (CEA) and containing either a DAP12- or a CD3ζ-derived signaling domain showed antigen redirected activation as they secreted pro-inflammatory cytokines specifically upon contact with CEA⁺ target cells. In addition, CD3ζ-expressing CAR MΦs exhibited significantly enhanced phagocytosis of CEA⁺ HT1080 cells. Our data establish human HSPCs as a suitable cell source to generate functional CAR MΦs and further support the use of CAR MΦs in the context of solid tumor therapy.