Biology Direct最新文献

Background: Cholangiocarcinoma (CCA) is an aggressive malignancy with limited treatment options. Despite the approval of chemotherapy and immune checkpoint inhibitors (ICIs) in clinical practice, treatment outcomes remain poor, largely due to the poorly immunogenic tumor microenvironment associated with this type of carcinoma. Necroptosis, an inflammatory form of programmed cell death, has emerged as a promising therapeutic target for stimulating antitumor immunity. Our previous study linked necroptosis to increased CD8 + T cell infiltration and T cell-induced PD-L1 expression in CCA cells, suggesting its role in enhancing ICI efficacy. However, the underlying mechanisms by which necroptosis-activated T cells induce PD-L1 expression remain unclear. Here, we investigate how necroptosis in CCA cells influences T cell response, which subsequently promotes PD-L1 expression, thus providing insights for optimizing necroptosis-based therapies in combination with ICIs.

Results: Conditioned medium from gemcitabine-induced necroptotic CCA cells triggers PBMC-derived T cell activation by upregulating the surface activation marker CD69 and promoting cytokine release, primarily IL-6 and IL-1β. This cytokine release subsequently induces PD-L1 expression in CCA cells via IL-6, as confirmed by IL-6 neutralizing antibodies. Furthermore, T cell killing assays demonstrated that pembrolizumab, an anti-PD-1 inhibitor, enhances T cell cytotoxicity against PD-L1-upregulated CCA cells. Additionally, bioinformatics analysis identified an IL-6 signaling-related gene signature associated with ICI responsiveness, suggesting potential biomarkers for personalized treatment strategies.

Conclusion: This study highlights that necroptosis shapes the tumor immune microenvironment by promoting T cell activation and IL-6-mediated PD-L1 upregulation in CCA cells. These findings support the integration of necroptosis-based therapies with ICIs as a sequential chemo-immunotherapy strategy. Additionally, the identified IL-6 signaling-related gene signature may serve as a biomarker for patient stratification and personalized treatment in CCA.

Background: Despite therapeutic advances, metastatic melanoma, and particularly brain metastasis (MBM), remains a lethal burden for patients. Existing single-cell studies offer a more detailed view of melanoma and its microenvironment, which is crucial to improve diagnosis and treatment.

Results: We here present a computational reanalysis of single-nucleus data comparing 15 MBM and 10 extracranial melanoma metastases (ECM), considering recent best practice recommendations. We used cell type-specific pseudobulking and omit imputation during patient integration to gain complementary insights. Interestingly, our analysis revealed high homogeneity in tumor cell expression profiles within and between MBM and ECM. However, MBM displayed even higher homogeneity but a more flexible energy metabolism, suggesting a specific metastatic adaptation to the putatively more restricted brain microenvironment. While tumor cells were homogeneous, the metastasis microenvironment, especially lymphocytes and related immune-tumor interaction pathways, exhibited greater divergence between MBM and ECM. Overall, this suggests that major differences between MBM and ECM are potentially driven by variations in their microenvironment. Finally, a comparison of single-cell data to previous bulk studies, including their deconvoluted putative cell types, showed significant differences, potentially causing divergent conclusions.

Conclusion: Our study contributed to refine the understanding of differences between MBM and ECM, suggesting these are potentially more influenced by their local microenvironments. Future research and therapies could possibly focus on the metabolic flexibility of melanoma brain metastases and patient-specific immune pathway alterations.

Background: Psoriasis is an immune-mediated chronic inflammatory condition characterized by significant neutrophil infiltration in the skin. Given that the spleen is the largest peripheral immune organ in the body, it is important to investigate whether it has any impact on skin inflammation in psoriasis.

Methods: To investigate this mechanism, a psoriatic mouse model was established by IMQ application. Flow cytometry and immunohistochemistry analyses were performed to determine the percentage of various immune cells in the spleen. The role of neutrophils was specifically assessed using the anti-Gr-1 antibody. Splenic granulopoiesis was evaluated using EdU labeling. To understand the spleen's role in skin inflammation, splenectomy was performed on the experimental mice. IL-6 levels were measured by ELISA, and P-STAT3 in neutrophils was detected via immunofluorescence. Further examination of IL-6's effects on neutrophil formation involved treating mice with IL-6 antibody. The severity of psoriasis was evaluated through histological staining and PASI scoring.

Results: Our study revealed that the spleens of psoriatic mice were enlarged compared to those of vehicle mice. Among immune cell populations, neutrophils showed the most significant changes, with marked increases in both spleen and skin of psoriatic mice and patients, contributing to disease progression. Post-splenectomy, neutrophil infiltration in the skin was reduced by approximately 60% in psoriatic mice. This indicates that the neutrophils in the skin were primarily derived from the spleen. Additionally, the spleen showed a notable capacity for granulopoiesis with elevated neutrophils. Moreover, we found elevated IL-6 levels in the skin, blood, and spleen in the model, which was decreased after splenectomy. Treatment with an IL-6 antibody reduced neutrophil formation in both the spleen and skin, which alleviated skin inflammation in psoriatic mice. Additionally, P-STAT3 signaling was decreased following IL-6 antibody treatment. The neutrophil infiltration in spleen and skin was decreased after injection with the inhibitor of P-STAT3, which also alleviated the inflammation of psoriatic model. Thus, IL-6 served as the dominant regulator of spleen granulopoiesis, a process potentially mediated by P-STAT3 signaling.

Conclusions: The spleen plays a crucial role in the immune microenvironment of psoriasis as a major site of granulopoiesis, influencing neutrophil infiltration in the skin of psoriatic mice. Additionally, IL-6 is a key regulator of neutrophil formation in the spleen of psoriatic mice, likely through P-STAT3-dependent mechanisms.

Over the last few decades, adipose tissue has attracted increasing attention in the field of regenerative medicine, thanks to discoveries related to its regenerative, anti-inflammatory, and pro-angiogenic properties. Over the years, with the advancement of sophisticated research around adipose tissue, there has been a shift from tissue transfer to cell transfer, and then to the application of cell-free derivatives and bioengineering. Understanding the evolution of this scientific revolution around adipose tissue not only helps clarify potential therapeutic products and indications but also allows us to discuss its limitations and future directions.

Due to the low response rate and severe side effects, the clinical efficacy of current immunotherapy for patients with colorectal cancer (CRC) remains unsatisfactory. Induction of immunogenic cell death (ICD) has been evidenced to be conducive to enhancing the survival benefit of immune checkpoint blockade (ICB) therapy. Protein regulator of cytokinesis 1 (PRC1) has been proven to be a tumor promoter in CRC and an immune marker. However, whether and how PRC1 is involved in the ICD regulation in CRC remains undiscovered. The current study identified the upregulation of PRC1 in CRC tissues and its prognostic value via bioinformatics analyses. Similarly, we determined the close correlation between PRC1 and ICD. In addition, knockdown of PRC1 induced ICD and downregulated PD-L1 expression in CRC cells, which was attenuated by ER stress inhibitor 4-PBA. PRC1 silencing elicited ER stress, but this effect was partially rescued by the ROS scavenger N-acetylcysteine. Mechanism investigation revealed that PRC1 could stimulate Wnt/β-catenin activation in CRC cells. According to results of rescue assays, activation of Wnt/β-catenin by BML-284 could partially reverse the effects of PRC1 knockdown on ER stress and ICD in CRC cells. Finally, the in vivo experiments demonstrated that silencing of PRC1 restrained tumor growth in CRC animal models. In conclusion, this study verified that inhibition of PRC1 expression could induce ICD in CRC by triggering ER stress via the Wnt/β-catenin signaling pathway. These findings highlight a novel molecular pathway whereby PRC1 exerts carcinogenic role in tumor immune microenvironment through ICD in CRC.

Background & aims: Gallbladder cancer (GBC) is characterised by a desmoplastic microenvironment rich in collagen fibres and extracellular matrix, contributing to increased matrix stiffness. SEMAs are overexpressed in various cancers but their expression and role in the crosstalk between activated gallbladder fibroblasts (GFs) and GBC cells within a stiff microenvironment remain unclear. Herein, we aimed to elucidate the expression patterns and tumour-promoting effects of SEMAs in activated GFs under the matrix stiffness microenvironment.

Methods: Masson staining assessed collagen deposition in GBC stroma. GFs were isolated from gallbladder tissues and cultured on silicon or polyacrylamide hydrogels. SEMA expression in GFs under different stiffness conditions was determined via RNA-seq and RT-qPCR. Transwell assays, tumorsphere-formation and Western blot assays were used to investigate the effects of GFs-derived SEMA7A on GBC epithelial-mesenchymal transition (EMT) and cancer stem-like traits. Subcutaneous tumour models were established by co-injecting GFs and GBC cells to assess SEMA7A's role in vivo. Co-immunoprecipitation, WB, Elisa and mutation assays were employed to elucidate the mechanism of SEMA7A involvement in GFs-GBC cell crosstalk.

Results: This study revealed a high-stiffness microenvironment in GBC, inducing GFs activation and SEMA7A paracrine through YAP/TAZ signalling. GFs-secreted SEMA7A under matrix stiffness microenvironment promoted GBC EMT and cancer stem-like traits. Mechanistically, GFs-secreted SEMA7A bound to its receptor integrin β1 instead of plexinC1 on GBC cells to induce the phosphorylation of p300 at S1834 and maintain the malignant phenotypes of GBC cells. Moreover, the SEMA7A/integrin β1 axis-induced p300 phosphorylation at S1834 was mediated by Akt activation (p-Akt at S473) in GBC cells.

Conclusions: Our findings demonstrate a complex stiffness/SEMA7A/integrin β1/AKT/p300 cascade mediating reciprocal interactions between GFs and GBC cells, offering a potential therapeutic target for patients with GBC.

Background: Metabolic alterations are closely associated with the exhaustion and immune deficiency of CD8⁺ tumor-infiltrating lymphocytes (TILs), while little is known about diffuse large B-cell lymphoma (DLBCL). This study aimed to elucidate the significance of the metabolic alterations in exhausted CD8⁺TILs and its underlying regulatory mechanism in DLBCL.

Methods: The metabolic alterations in exhausted CD8⁺TILs in DLBCL were evaluated through single-cell RNA sequencing (scRNA-seq). The crucial metabolic pathway and its significance in the biological function of exhausted CD8⁺TILs were investigated by scRNA-seq and RNA sequencing. The marker gene in crucial metabolic pathway, and its correlations between exhaustion status, the tumor microenvironment (TME) composition, clinicopathological characteristics, prognosis, and immune checkpoint blockade (ICB) therapy efficacy were evaluated by scRNA-seq, RNA sequencing, immunohistochemistry, and RT-qPCR. Furthermore, the underlying regulatory mechanism involved in the metabolic alteration related to CD8⁺TILs exhaustion was explored through scRNA-seq, RNA sequencing, and somatic mutation analysis.

Results: Our study illustrated the metabolic heterogeneity in CD8⁺TILs, and demonstrated that oxidative phosphorylation (OXPHOS) was the crucial pathway in CD8⁺TILs exhaustion. The high OXPHOS activity indicated the immune deficiency in exhausted CD8⁺TILs, and UQCRFS1 was identified as a marker gene. High UQCRFS1 indicated the immunosuppressive TME, severe clinicopathological characteristics, including activated B-cell-like subtype, high IPI and PS score, advanced stage, dismal prognosis, and resistance to ICB therapy. Furthermore, MYC-related signaling and P2RY8 mutation in DLBCL may regulate the UQCRFS1 expression in exhausted CD8⁺TILs.

Conclusions: Our study highlights the importance of OXPHOS activity in CD8⁺TILs exhaustion and suggests its possible regulatory mechanism, which is feasible in clinical evaluation and beneficial for novel immunotherapeutic approaches in DLBCL.

Background: Globally, HCC is still one of the most common cancers. N6-methyladenosine (m⁶A) modifications and long-stranded noncoding RNAs (lncRNAs) play key roles in regulating HCC progression. The role of the lncRNA RNF144A-AS1, a newly identified lncRNA, in HCC is unclear.

Methods: In HCC, RNF144A-AS1 expression level and its effect on prognosis were investigated by bioinformatics. CCK-8, EdU, scratch assay, and Transwell assays were used to detect the impact of RNF144A-AS1 on hepatocellular carcinoma malignancy. Assays using MeRIP-qPCR, RIP, and Actinomycin D were used to study the effects of m⁶A methylation on hepatocellular carcinoma malignant phenotypes. Revealing the potential mechanism of action of RNF144A-AS1 by luciferase reporter gene assay, PCR, and Western blot assays, and Nude mice subcutaneous load cell and lung metastasis models were used to verify the effect of RNF144A-AS1 on the malignant phenotype of tumors in vivo.

Results: The lncRNA RNF144A-AS1 was significantly upregulated in HCC, and it was significantly associated with poor prognosis. Functionally, HCC cells with RNF144A-AS1 knockdown were inhibited in terms of proliferation, migration, and invasion. Further studies in vivo confirmed that RNF144A-AS1 knockdown inhibited tumor cell growth and metastasis. Mechanistically, METTL3 increased the m⁶A modification and stability of RNF144A-AS1 in an IGF2BP1-associated manner. In addition, RNF144A-AS1 was inhibited by sponge-like miR-1301-3p to inhibit RNF38 degradation, thereby promoting the HCC malignant phenotype.

Conclusion: The RNF144A-AS1 gene is affected by METTL3/IGF2BP1 methylation and encourages liver cancer proliferation and metastasis by increasing expression of RNF38 through sponge-like miR-1301-3p. RNF144-AS1 promises to be a therapeutic target for HCC.

Background: The mucin-degrading bacterium Akkermansia muciniphila has attracted enormous interest for its beneficial effects on human health. However, growing evidence suggests that the Akkermansia genus is populated by several species that differ in phenotypic characteristics and association with human traits.

Results: We present the most comprehensive phylotaxonomic analysis of Akkermansia genomes in terms of sample size and host representation. By applying approaches based on average nucleotide identities and on the biological species concept, we show that the Akkermansia genus comprises at least 31 species, 13 of which can be detected in humans. The largest species diversity is contributed by non-human and non-mouse animals, and limited evidence of species-specificity is evident, with several Akkermansia species detected in phylogenetically distant animals. Analysis of accessory gene content among species also failed to reveal species-specific or diet-specific associations, but rather reflected genome size. Thus, A. muciniphila and A. ignis have, on average, small genomes and retain a part of genes that characterize either A. massiliensis or A. sp004167605/A. biwaensis. Finally, investigation of the population structure of A. muciniphila, the species that has been more intensely investigated due to its effects on human health, clearly distinguished two phylogroups corresponding to AmIa and AmIb. However, analysis of laboratory mouse-derived genomes revealed that additional populations, specific to these animals, exist. Such populations show limited evidence of admixture, suggesting bottleneck or competition effects.

Conclusions: Our data support the concept that the genetic diversity of Akkermansia should be taken into account in experimental settings. They also call for sequencing efforts to characterize the wider genetic diversity of Akkermansia bacteria.

Chloride intracellular channels (CLICs) are a family of six evolutionarily conserved proteins with diverse functions. Previously, we identified CLIC2, as the fifth-ranked master regulator associated with diffuse-type gastric cancer (dGC) showing increased expression in tumors. Here we used bulk, as well as single cell sequencing datasets of dGC, to demonstrate for the first time a direct association of CLIC2 with the microsatellite stable GC and, furthermore, the expression of CLIC2 in macrophages (MCs), and endothelial cells (ECs) populating gastric tissue. We generated CLIC2 knock-out THP-1 monocytic cells (THP-1CLIC2_KO) determining that while CLIC2 deletion had no observable effect on monocytes, THP-1CLIC2_KO macrophages exhibited significant morphological changes, including increased membrane protrusions, and upregulated expression of CD11b, CD11c, CD80, and CD86 markers. Furthermore, cytokine secretion profiling of THP-1CLIC2_KO differentiated cells revealed elevated secretion of CCL8, alongside reduced secretion of IL-1β, IL-6, and osteoprotegerin (OPG). Additionally, we observed increased phosphorylation of Shp1 phosphatase with the concomitant absence of Stat3 phosphorylation, which impaired downstream signaling, in line with the evidence that Clic2 interacts with both Shp1 and Stat3. Based on these findings, we suggest that CLIC2 plays a pivotal role in regulating monocyte-to-macrophage differentiation by modulating the Stat3 signaling pathway, thus enhancing gastric cancer progression by establishing a tumor-permissive microenvironment.