Identification of Surface Markers and Functional Characterization of Myeloid Derived Suppressor Cell-Like Adherent Cells.

Myeloid-derived suppressor cell (MDSC)-like adherent cells (MLACs) are a recently identified CD11b+ F4/80- myeloid cell subset that can infiltrate tumors early in development and promote their growth. Because of these functions, MLACs play an important role in establishing an immunosuppressive tumor microenvironment (TME). However, the lack of MLAC-specific markers has hampered further characterization of this cell type. This study identifies the gene signature of MLACs by analyzing RNA-sequencing (RNA-seq) and public single-cell RNA-seq data, revealing that MLACs are an independent cell population that are distinct from other intratumoral myeloid cells. After combining proteome analysis of membrane proteins with RNA-seq data, H2-Ab1 and CD11c are indicated as marker proteins that can support the isolation of MLAC subsets from CD11b+ F4/80- myeloid cells by fluorescence-activated cell sorting. The CD11b+ F4/80- H2-Ab1+ and CD11b+ F4/80- CD11c+ MLAC subsets represent approximately half of the MLAC population that is isolated based on their adhesion properties and possess gene signatures and functional properties similar to those of the MLAC population. Additionally, membrane proteome analysis suggests that MLACs express highly heterogeneous surface proteins. This study facilitates an integrated understanding of heterogeneous intratumoral myeloid cells, as well as the molecular and cellular details of the development of an immunosuppressive TME.

In vivo optical imaging of tumor stromal cells with hypoxia-inducible factor activity.

Tumors contain various stromal cells, such as immune cells, endothelial cells, and fibroblasts, which contribute to the development of a tumor-specific microenvironment characterized by hypoxia and inflammation, and are associated with malignant progression. In this study, we investigated the activity of intratumoral hypoxia-inducible factor (HIF), which functions as a master regulator of the cellular response to hypoxia and inflammation. We constructed the HIF activity-monitoring reporter gene hypoxia-response element-Venus-Akaluc (HVA) that expresses the green fluorescent protein Venus and modified firefly luciferase Akaluc in a HIF activity-dependent manner, and created transgenic mice harboring HVA transgene (HVA-Tg). In HVA-Tg, HIF-active cells can be visualized using AkaBLI, an ultra-sensitive in vivo bioluminescence imaging technology that produces an intense near-infrared light upon reaction of Akaluc with the D-luciferin analog AkaLumine-HCl. By orthotopic transplantation of E0771, a mouse triple negative breast cancer cell line without a reporter gene, into HVA-Tg, we succeeded in noninvasively monitoring bioluminescence signals from HIF-active stromal cells as early as 8 days after transplantation. The HIF-active stromal cells initially clustered locally and then spread throughout the tumors with growth. Immunohistochemistry and flow cytometry analyses revealed that CD11b+ F4/80+ macrophages were the predominant HIF-active stromal cells in E0771 tumors. These results indicate that HVA-Tg is a useful tool for spatiotemporal analysis of HIF-active tumor stromal cells, facilitating investigation of the roles of HIF-active tumor stromal cells in tumor growth and malignant progression.

Recent Trends and Opportunities for the Targeted Immuno-Nanomaterials for Cancer Theranostics Applications.

The targeted delivery of cancer immunotherapies has increased noticeably in recent years. Recent advancements in immunotherapy, particularly in blocking the immune checkpoints (ICs) axis, have shown favorable treatment outcomes for multiple types of cancer including melanoma and non-small-cell lung cancer (NSLC). Engineered micromachines, including microparticles, and nanoplatforms (organic and inorganic), functionalized with immune agonists can effectively deliver immune-targeting molecules to solid tumors. This review focuses on the nanomaterial-based strategies that have shown promise in identifying and targeting various immunological markers in the tumor microenvironment (TME) for cancer diagnosis and therapy. Nanomaterials-based cancer immunotherapy has improved treatment outcomes by triggering an immune response in the TME. Evaluating the expression levels of ICs in the TME also could potentially aid in diagnosing patients who would respond to IC blockade therapy. Detecting immunological checkpoints in the TME using noninvasive imaging systems via tailored nanosensors improves the identification of patient outcomes in immuno-oncology (IO). To enhance patient-specific analysis, lab-on-chip (LOC) technology is a rapid, cost-effective, and accurate way of recapitulating the TME. Such novel nanomaterial-based technologies have been of great interest for testing immunotherapies and assessing biomarkers. Finally, we provide a perspective on the developments in artificial intelligence tools to facilitate ICs-based nano theranostics toward cancer immunotherapy.