The increasing understanding of ferroptosis has indicated its role and therapeutic potential in cancer; however, this knowledge has yet to be translated into effective therapies. Glioblastoma (GBM) patients face a bleak prognosis and encounter challenges due to the limited treatment options available. In this study, we conducted a genome-wide CRISPR-Cas9 screening in the presence of a ferroptosis inducer (RSL3) to identify the key driver genes involved in ferroptosis. We identified ALOX15, a key lipoxygenase (LOX), as an essential driver of ferroptosis. Small activating RNA (saRNA) was used to mediate the expression of ALOX15 promoted ferroptosis in GBM cells. We then coated saALOX15-loaded mesoporous polydopamine (MPDA) with Angiopep-2-modified macrophage membranes (MMs) to reduce the clearance by the mononuclear phagocyte system (MPS) and increase the ability of the complex to cross the blood-brain barrier (BBB) during specific targeted therapy of orthotopic GBM. These generated hybrid nanoparticles (NPs) induced ferroptosis by mediating mitochondrial dysfunction and rendering mitochondrial morphology abnormal. In vivo, the modified MM enabled the NPs to target GBM cells, exert a marked inhibitory effect on GBM progression, and promote GBM radiosensitivity. Our results reveal ALOX15 to be a promising therapeutic target in GBM and suggest a biomimetic strategy that depends on the biological properties of MMs to enhance the in vivo performance of NPs for treating GBM.

Prostate cancer rarely responds to immune-checkpoint blockade (ICB) therapies. Cancer-associated fibroblasts (CAF) are critical components of the immunologically “cold” tumor microenvironment and are considered a promising target to enhance the immunotherapy response. In this study, we aimed to reveal the mechanisms regulating CAF plasticity to identify potential strategies to switch CAFs from protumorigenic to antitumor phenotypes and to enhance ICB efficacy in prostate cancer. Integration of four prostate cancer single-cell RNA sequencing datasets defined protumorigenic and antitumor CAFs, and RNA-seq, flow cytometry, and a prostate cancer organoid model demonstrated the functions of two CAF subtypes. Extracellular matrix–associated CAFs (ECM-CAF) promoted collagen deposition and cancer cell progression, and lymphocyte-associated CAFs (Lym-CAF) exhibited an antitumor phenotype and induced the infiltration and activation of CD8+ T cells. YAP1 activity regulated the ECM-CAF phenotype, and YAP1 silencing promoted switching to Lym-CAFs. NF-κB p65 was the core transcription factor in the Lym-CAF subset, and YAP1 inhibited nuclear translocation of p65. Selective depletion of YAP1 in ECM-CAFs in vivo promoted CD8+ T-cell infiltration and activation and enhanced the therapeutic effects of anti-PD-1 treatment on prostate cancer. Overall, this study revealed a mechanism regulating CAF identity in prostate cancer and highlighted a therapeutic strategy for altering the CAF subtype to suppress tumor growth and increase sensitivity to ICB. Significance: YAP1 regulates cancer-associated fibroblast phenotypes and can be targeted to switch cancer-associated fibroblasts from a protumorigenic subtype that promotes extracellular matrix deposition to a tumor-suppressive subtype that stimulates antitumor immunity and immunotherapy efficacy.

Background and aims: Endosialin, also known as tumor endothelial marker1 or CD248, is a transmembrane glycoprotein that is mainly expressed in cancer-associated fibroblasts (CAFs) in hepatocellular carcinoma (HCC). Our previous study has found that endosialin-positive CAFs could recruit and induce the M2 polarization of macrophages in HCC. However, whether they may regulate other types of immune cells to promoting HCC progression is not known. Approach and results: The growth of both subcutaneous and orthotopic HCC tumors was significantly inhibited in endosialin knockout (EN^KO) mice. Single-cell sequencing and flow cytometry analysis showed that tumor tissues from EN^KO mice had increased CD8⁺ T cell infiltration. Mixed HCC tumor with Hepa1-6 cells and endosialin knockdown fibroblasts also showed inhibited growth and increased CD8⁺ T cell infiltration. Data from in vitro co-culture assay, chemokine array and antibody blocking assay, RNA-seq and validation experiments showed that endosialin inhibits the phosphorylation and nuclear translocation of STAT1 in CAFs. This inhibition leads to a decrease in CXCL9/10 expression and secretion, resulting in the suppression of CD8⁺ T cell infiltration. High level of endosialin protein expression was correlated with low CD8⁺ T infiltration in the tumor tissue of HCC patients. The combination therapy of endosialin antibody and PD-1 antibody showed synergistic antitumor effect compared with either antibody used individually. Conclusions: Endosialin could inhibit CD8⁺ T cell infiltration by inhibiting the expression and secretion of CXCL9/10 in CAFs, thus promote HCC progression. Combination therapy with endosialin antibody could increase the antitumor effect of PD-1 antibody in HCC, which may overcome the resistance to PD-1 blockade.

Background: The tumor microenvironment (TME) plays an important role in the progression of renal cell carcinoma (RCC). Cancer-associated fibroblasts (CAFs) are considered to constitute a major component of the TME and participate in various tumor-promoting molecular events. We have previously confirmed that CD248 represents a promising biomarker of CAFs, which may provide insight into CAF-based tumor-promoting effects. However, CAF-mediated tumor progression and the potential mechanism of CD248 remain largely unknown in RCC patients.Methods: Expression profiling and clinical data of RCC patients were obtained from The Cancer Genome Atlas (TCGA) database. An MCP-counter algorithm and Kaplan–Meier survival analysis were performed to explore the prognostic value of CAFs and CD248, respectively. A Pearson correlation coefficient test and Student’s t-test were employed to evaluate the relationship between immunosuppressive TME and CD248 or CAFs. Immunohistochemistry and immunofluorescence staining were performed to confirm CD248 expression within CAFs. CD248-specific siRNA was used to investigate the potential function of CD248 in CAF tumor promotion. Differentially expressed genes (DEGs), weighted gene co-expression network analysis (WGCNA), and enrichment analysis were conducted to clarify the function of CD248⁺ CAFs in RCC progression and the associated regulatory mechanism.Results: CD248 overexpression and CAF infiltration could predict poor RCC prognosis, which may involve the immunosuppressive TME. CD248 may serve as a promising CAFs biomarker and be involved with the tumor-promoting effect of CAFs. Moreover, CD248⁺ CAF infiltration may contribute to RCC progression and an immunosuppressive TME through cell-extracellular matrix (ECM) interactions and metabolism regulation.Conclusion: CD248⁺ CAFs participate in the regulation of RCC progression and immunosuppressive TME, which may represent a novel prognostic and therapeutic target for RCC.

Background: Chronic liver injury induces pathological repair, resulting in fibrosis, during which hepatic stellate cells (HSCs) are activated and transform into myofibroblasts. CD248 is mainly expressed on myofibroblasts and was considered as a promising target to treat fibrosis. The primary aim of this study was to generate a CD248 specific antibody-drug conjugate (ADC) and evaluate its therapeutic efficacy for liver fibrosis and its safety in vivo. Methods: CD248 expression was examined in patients with liver cirrhosis and in mice with CCl₄-induced liver fibrosis. The ADC IgG78-DM1, which targets CD248, was prepared and its bioactivity on activated primary HSCs was studied. The anti-fibrotic effects of IgG78-DM1 on liver fibrosis were evaluated in CCl₄-induced mice. The reproductive safety and biosafety of IgG78-DM1 were also evaluated in vivo. Results: CD248 expression was upregulated in patients with liver cirrhosis and in CCl₄-induced mice, and was mainly expressed on alpha smooth muscle actin (α-SMA)⁺ myofibroblasts. IgG78-DM1 was successfully generated, which could effectively bind with and kill CD248⁺ activated HSCs in vitro and inhibit liver fibrosis in vivo. In addition, IgG78-DM1 was demonstrated to have qualified biosafety and reproductive safety in vivo. Conclusions: Our study demonstrated that CD248 could be an ideal target for myofibroblasts in liver fibrosis, and CD248-targeting IgG78-DM1 had excellent anti-fibrotic effects in mice with liver fibrosis. Our study provided a novel strategy to treat liver fibrosis and expanded the application of ADCs beyond tumors. Graphic

Background: Renal cell carcinoma (RCC) is the most common malignancy in the urinary system. Despite substantial improvements in available treatment options, the survival outcome of advanced RCC is unsatisfactory. Identifying novel biomarkers to assist in early diagnosis and to screen patients who are sensitive to immunotherapy would be beneficial. CD248 is a promising candidate that deserves to be investigated.Methods: The Cancer Genome Atlas (TCGA) data set and clinical specimens were adopted to analyze the expression of CD248 between normal and tumor tissues. Univariate and multivariate Cox regression analyses were employed to identify independent prognostic factors and construct a CD248-based prognostic signature. The correlation among the present signature, tumor-infiltrating immune cells (TIICs), the tumor mutation burden (TMB), and immunomodulatory molecules was evaluated. The weighted gene co-expression network analysis (WGCNA), the enrichment analysis, and the miRNA correlation analysis were performed to explore the underlying mechanism of CD248 in the progression of RCC.Results: The overexpression of CD248 in RCC was related to a poor prognosis, and a CD248-based prognostic signature could precisely stratify patients with RCC with different survival outcomes regardless of the training or testing cohort. The present signature could reflect the immunosuppressive landscape of RCC (i.e., increased infiltration of regulatory T cells and upregulated immune checkpoints), accompanied by deteriorated clinicopathologic indexes. The TMB and immunostimulatory molecules expression also increased with the risk score generated from the present signature. CD248 co-expressed gene sets were identified through the WGCNA algorithm, and several immunosuppressive Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were significantly enriched. The result of CD248-correlated miRNA further emphasized the importance of CD248 in RCC.Conclusion: CD248 is a valuable biomarker to improve the diagnostic and therapeutic efficiency of RCC. The immunosuppressive effect of CD248 co-expressed genes may provide insight for the present study, and miRNA would help to reveal the mechanism of the expressive regulation of CD248.