Integrated single-cell and bulk RNA sequencing analyses identify an immunotherapy nonresponse-related fibroblast signature in gastric cancer.

Factors that determine nonresponse to immune checkpoint inhibitor (ICI) remain unclear. The protumor activities of cancer-associated fibroblasts (CAFs) suggest that they are potential therapeutic targets for cancer treatment. There is, however, a lack of CAF-related signature in predicting response to immunotherapy in gastric cancer (GC). Single-cell RNA sequencing (scRNA-seq) and RNA sequencing (RNA-seq) data of GC immunotherapy were downloaded from the Gene Expression Omnibus database. Bulk RNA-seq data were obtained from The Cancer Genome Atlas. The R package 'Seurat' was used for scRNA-seq data processing. Cellular infiltration, receptor-ligand interactions, and evolutionary trajectory analysis were further explored. Differentially expressed genes affecting overall survival were obtained using the limma package. Weighted Gene Correlation Network Analysis was used to identify key modules of immunotherapy nonresponder. Prognostic model was constructed by univariate Cox and least absolute contraction and selection operator analysis using the intersection of activated fibroblast genes (AFGs) with key module genes. The differences in clinicopathological features, immune microenvironment, immunotherapy prediction, and sensitivity to small molecule agents between the high- and low-risk groups were further investigated. Based on scRNA-seq, we finally identified 20 AFGs associations with the prognosis of GC patients. AFGs' high expression levels were correlated with both poor prognosis and tumor progression. Three genes (FRZB, SPARC, and FKBP10) were identified as immunotherapy nonresponse-related fibroblast genes and used to construct the prognostic signature. This signature is an independent significant risk factor affecting the clinical outcomes of GC patients. Remarkably, there were more CD4 memory T cells, resting mast cells, and M2 macrophages infiltrating in the high-risk group, which was characterized by higher tumor immune exclusion. Moreover, patients with higher risk scores were more prone to not respond to immunotherapy but were more sensitive to various small molecule agents, such as memantine. In conclusion, this study constructed a fibroblast-associated ICI nonresponse gene signature, which could predict the response to immunotherapy. This study potentially revealed a novel way to overcome immune resistance in GC.

Single-cell analysis of a progressive Rosai-Dorfman disease affecting the cerebral parenchyma: a case report.

Neurologic Rosai-Dorfman disease (RDD) is a rare type of non-Langerhans cell histiocytosis that affects the central nervous system. Most neurologic RDDs grow like meningiomas, have clear boundaries, and can be completely resected. However, a few RDDs are invasive and aggressive, and no effective treatment options are available because the molecular mechanisms involved remain unknown. Here, we report a case of deadly and glucocorticoid-resistant neurologic RDD and explore its possible pathogenic mechanisms via single-cell RNA sequencing. First, we identified two distinct but evolutionarily related histiocyte subpopulations (the C1Q+ and SPP1+ histiocytes) that accumulated in the biopsy sample. The expression of genes in the KRAS signaling pathway was upregulated, indicating gain-of-function of KRAS mutations. The C1Q+ and SPP1+ histiocytes were highly differentiated and arrested in the G1 phase, excluding the idea that RDD is a lympho-histio-proliferative disorder. Second, although C1Q+ histiocytes were the primary RDD cell type, SPP1+ histiocytes highly expressed several severe inflammation-related and invasive factors, such as WNT5A, IL-6, and MMP12, suggesting that SPP1+ histiocytes plays a central role in driving the progression of this disease. Third, oligodendrocytes were found to be the prominent cell type that initiates RDD via MIF and may resist glucocorticoid treatment via the MDK and PTN signaling pathways. In summary, in this case, we report a rare presentation of neurologic RDD and provided new insight into the pathogenic mechanisms of progressive neurologic RDD. This study will also offer evidence for developing precision therapies targeting this complex disease.

Unlocking the potential: phenylboronic acid as a nuclear-targeting boron agent for neutron capture therapy.

It has been proposed that boron neutron capture therapy (BNCT) holds promise as a treatment modality for melanoma. However, the effectiveness of boron agents in delivery remains a critical issue to be addressed for BNCT. To this end, phenylboronic acid, which exhibits good water solubility and low cytotoxicity similar to BPA, has been investigated as a potential nuclear-targeting boron agent. The boron concentration of phenylboronic acid was found to be 74.47 ± 12.17 ng/106 B16F10 cells and 45.77 ± 5.64 ng/106 cells in the nuclei. Molecular docking experiments were conducted to investigate the binding of phenylboronic acid to importin proteins involved in nuclear transport. The potential of phenylboronic acid to serve as a desirable nucleus-delivery boron agent for neutron capture therapy in melanoma warrants further exploration.

In-depth human immune cellular profiling from newborn to frail.

Immune functional decline and remodeling accompany aging and frailty. It is still largely unknown how changes in the immune cellular composition differentiate healthy individuals from those become frail at a relatively early age. Our aim in this exploratory study was to investigate immunological changes from newborn to frailty, and the association between health statute and various immune cell subtypes. The participants analyzed in this study covered human cord blood cells and peripheral blood cells collected from young adults, healthy and frail old individuals. A total of 30 immune cell subsets was performed by flow cytometry based on the surface markers of immune cells. Furthermore, frailty was investigated for its relations with various leukocyte subpopulations. Frail individuals exhibited a higher CD4/CD8 ratio, a higher proportion of CD4+ central memory T (TCM) cells, CD8+ effector memory T cells, CD27- switched memory B (CD27-BSM) cells, CD27+ switched memory B cells, age-associated B cells (ABCs) and CD38-CD24- B cells, and a lower proportion of naïve CD8 + T cells and progenitor B cells. The Frailty index score was found to be associated with naïve T cells, CD4/CD8 ratio, ABCs, CD27-BSM cells, and CD4+ TCM cells. Our findings conducted a relatively comprehensive and extensive atlas of age- and frailty-related changes in peripheral leukocyte subpopulations from newborn to frailty. The immune phenotypes identified in this study can contribute to a deeper understanding of immunosenescence in frailty and may provide a rationale for future interventions and diagnosis.

Fludarabine Enhances Radiosensitivity by Promoting Ferroptosis in B-Cell Lymphoma.

The objective of this study is to investigate the impact of fludarabine, a signal transducer and activator of transcription-1 (STAT1) inhibitor, on the radiosensitivity of B-cell lymphoma (BCL) and to explore the underlying mechanisms. Radiotherapy is one of the primary treatments for BCL, and STAT1 plays a critical role in the transcription of cell proliferation-related genes, which are associated with radiotherapy and ferroptosis. This study aims to determine whether fludarabine can enhance the radiosensitivity of BCL and to elucidate the molecular pathways involved. Various in vitro methodologies, including CCK-8 assays, clonogenic formation assays, immunohistochemistry, immunofluorescence, flow cytometry, qRT-PCR, and Western blot analyses, were employed in B-cell lymphoma cell models to thoroughly investigate the effects of fludarabine on radiosensitivity. Subsequently, the obtained results were further validated through in vivo animal models and by examining human diffuse large B-cell lymphoma (DLBCL) cancer samples. Our findings demonstrate that the combination of fludarabine and irradiation synergistically inhibits cell viability and colony formation, while inducing apoptosis and ferroptosis in B-cell lymphoma cell lines Raji and Su-DHL-10. Moreover, fludarabine was found to enhance the ferroptosis induced by radiation, thereby synergistically impeding the growth of BCL. In vivo experiments confirmed these findings, revealing that the intraperitoneal injection of fludarabine significantly enhanced the inhibitory effects of radiation on Raji cell xenograft models, leading to an increased percentage of ferroptosis compared to models without fludarabine. Additionally, the administration of liproxstatin-1, a ferroptosis inhibitor, attenuated the inhibition of xenograft growth caused by the combination of fludarabine and irradiation. Furthermore, our analysis of clinical data revealed that increased co-expression of STAT1 and GPX4 is associated with poor overall survival in patients with diffuse large B-cell lymphoma. These results highlight the potential of fludarabine to enhance radiosensitivity and ferroptosis induction as a promising therapeutic strategy for BCL. Our results demonstrated that fludarabine promoted radiation-induced BCL death through the ferroptosis pathway. We have identified a previously unrecognized mechanism in the fludarabine and radiation combination, indicating that it is necessary to conduct prospective clinical trials to verify this new treatment regimen in BCL.