Diffuse Large B-cell Lymphoma Tissues Research Articles

APOC1 knockdown induces apoptosis and decreases angiogenesis in diffuse large B-cell lymphoma cells through blocking the PI3K/AKT/mTOR pathway.

Diffuse large B-cell lymphoma (DLBCL) is a highly heterogeneous metastatic lymphoma that can be treated by targeting angiogenesis. Apolipoprotein C1 (APOC1) plays a significant role in the proliferation and metastasis of various malignant tumors; however, its role in DLBCL-particularly its effects on angiogenesis-remains largely unexplored. This study investigates the correlation between APOC1 expression and patient prognosis in DLBCL. Using APOC1 gene knockdown, apoptosis, migration, and invasion were assessed through flow cytometry, the EDU assay, wound healing, and Transwell assays. Additionally, human umbilical vein endothelial cells (HUVEC) angiogenesis was evaluated. Advanced techniques, such as immunofluorescence, TUNEL assay, and immunohistochemical labeling were employed to analyze the effects of APOC1 knockdown on the PI3K/AKT/mTOR signaling pathway and tumor formation in nude mice. Results showed that APOC1 is overexpressed in DLBCL tissues and cells, with high APOC1 levels associated with poor patient prognosis. In vitro experiments revealed that APOC1 knockdown increased apoptosis and inhibited cell proliferation, migration, invasion, HUVEC angiogenesis, and PI3K/AKT/mTOR signaling pathway protein expression in DLBCL cells. Similarly, in vivo studies demonstrated that APOC1 knockdown significantly reduced tumor growth, angiogenesis-related proteins, and phosphorylated PI3K/AKT/mTOR pathway proteins in nude mice. APOC1 knockdown promotes apoptosis and suppresses angiogenesis in DLBCL cells by inhibiting the PI3K/AKT/mTOR pathway.

Diffuse large B-cell lymphoma cell-derived exosomal NSUN2 stabilizes PDL1 to promote tumor immune escape and M2 macrophage polarization in a YBX1-dependent manner.

Diffuse large B-cell lymphoma (DLBCL) is a prevalent and aggressive form of non-Hodgkin's lymphoma with a complex etiology. NOP2/Sun domain 2 (NSUN2) is an RNA methyltransferase that has been linked to the regulation of gene expression in various cancers. However, the function of NSUN2 in DLBCL, specifically its contribution to exosome-driven tumor progression, remains to be thoroughly elucidated. Quantitative real-time polymerase chain reaction was used to analyze the expression of NSUN2 and programmed death ligand 1 variant (PDL1). Western blotting assay was performed to detect the protein levels of NSUN2, PDL1 and Y-box binding protein 1 (YBX1). Cell proliferation was analyzed by cell counting kit-8 and 5-Ethynyl-2'-deoxyuridine assays. Cell apoptosis and CD206-positive cells were quantified by flow cytometry. The levels of tumor necrosis factor-alpha and interferon-γ in cell supernatant were analyzed by enzyme-linked immunosorbent assays. m6A RNA immunoprecipitation and RNA pull-down assays were performed to determine the association between NSUN2 and PDL1. An RNA immunoprecipitation assay was used to analyze the association of YBX1 and PDL1. In vitro findings were validated in a mouse model. NSUN2 was overexpressed in DLBCL tissues and cells. DLBCL cell-derived exosomes facilitated the transfer of NSUN2 to DLBCL cells, which in turn promoted tumor cell proliferation, M2 macrophage polarization, and immune escape and inhibited cell apoptosis. In addition, NSUN2 stabilized PDL1 mRNA through an m5C-dependent mechanism and a YBX1-dependent pathway. Moreover, the suppression of PDL1 significantly mitigated the effects induced by NSUN2 within DLBCL cell-derived exosomes on cellular proliferation, apoptosis, M2 macrophage polarization, and immune evasion. Further, DLBCL cell-derived exosomal NSUN2 promoted tumor growth by regulating PDL1. NSUN2 in DLBCL cell-derived exosomes stabilized PDL1 in a YBX1-dependent manner and thus promoted tumor immune escape and M2 macrophage polarization. These findings highlight the potential of targeting the NSUN2-PDL1 axis as a novel therapeutic strategy for DLBCL.

PDLIM1, a novel miR-3940-5p target, regulates the malignant progression of diffuse large B-cell lymphoma

ABSTRACT Background PDZ And LIM domain protein 1 (PDLIM1), a protein-coding gene, has been widely reported to exhibit differential expression patterns across various human cancers, including hematological malignancies. This study aimed to investigate PDLIM1 expression pattern and its functional role in diffuse large B-cell lymphoma (DLBCL) both in vitro and in vivo. Methods PDLIM1 expression patterns were reanalyzed using data from the Gene Expression Omnibus, and the results were subsequently validated in patient tissue samples and a panel of four DLBCL cell lines. MicroRNA-3940-5p (miR-3940-5p) was identified as an upstream regulator of PDLIM1. The interaction between PDLIM1 and miR-3940-5p and its effects on DLBCL cellular activities and cancer development were further explored using a DLBCL mouse model. Results Elevated PDLIM1 expression was observed in DLBCL cells and tissues. Reduced cell proliferation and increased DLBCL cell apoptosis were observed following the knockdown of this gene. Furthermore, short hairpin RNA (shRNA)-mediated PDLIM1 knockdown diminished tumorigenesis of DLBCL cells in nude mice. miR-3940-5p was identified as an upstream regulator of PDLIM1. PDLIM1 expression and function were negatively modulated by the upregulation of miR-3940-5p, consequently affecting the malignant phenotype of DLBCL cells. Conclusion These findings suggest that the miR-3940-5p/PDLIM1 axis may play a crucial role in DLBCL pathogenesis and could potentially be exploited for therapeutic interventions.

EZB-type diffuse large B-cell lymphoma cell lines have superior migration capabilities compared to MCD-type.

Diffuse large B-cell lymphoma (DLBCL) represents the most prevalent aggressive B-cell lymphoma. The group is heterogeneous and the outcome is variable. A variety of approaches have been employed with the objective of improving the stratification of DLBCL patients according to their prognosis, based on the cell of origin. Recently, distinct genetic subtypes of DLBCL have been identified. Given the importance of cell migration in immune cells, the objective of this study was to ascertain whether different genetic subtypes of DLBCL exhibit disparate migration abilities. MCD- and EZB-type DLBCL cell lines were subjected to testing to ascertain their basal velocity in straight microchannels and their ability to overcome tight constrictions of 2 μm. The EZB-type cell lines showed superior basal migration velocity and constriction passage time, and a similar trend was observed in live cell imaging of native human DLBCL tissue. In addition, MCD-type DLBCL exhibited significantly elevated levels of nuclear lamin A/C, which is responsible for the stiffness of the nuclear envelope and could thus explain the disparate migration behaviours observed among these subtypes. Our study suggests that different genetic subtypes of DLBCL may not only influence the outcome after therapy but also the motility of the tumour cells.

Rupatadine-inhibited OTUD3 promotes DLBCL progression and immune evasion through deubiquitinating MYL12A and PD-L1

The obstacle to effectively treating Diffuse Large B-cell Lymphoma (DLBCL) lies in the resistance observed toward standard therapies. Identifying therapeutic targets that prove effective for relapsed or refractory patients poses a significant challenge. OTUD3, a deubiquitinase enzyme, is overexpressed in DLBCL tissues. However, its role in DLBCL has not been investigated. Our study has brought to light the multifaceted impact of OTUD3 in DLBCL. Not only does it enhance cell survival through the deubiquitination of MYL12A, but it also induces CD8+ T cell exhaustion within the local environment by deubiquitinating PD-L1. Our findings indicate that the OTUD3 inhibitor, Rupatadine, exerts its influence through competitive binding with OTUD3. This operation diminishes the deubiquitination of both MYL12A and PD-L1 by OTUD3. This research unveils the central and oncogenic role of OTUD3 in DLBCL and highlights the potential clinical application value of the OTUD3 inhibitor, Rupatadine. These findings contribute valuable insights into addressing the challenges of resistant DLBCL cases and offer a promising avenue for further clinical exploration.

RPRD1B/CREPT facilitates the progression of diffuse large B-cell lymphoma by inhibiting apoptosis through the NF-κB signaling pathway

Objective: To investigate the role of RPRD1B in the progression of diffuse large B-cell lymphoma (DLBCL) and its potential as a therapeutic target. Methods: This study analyzed RPRD1B expression in DLBCL and normal tissues using public databases and assessed its prognostic impact through survival analysis. In vitro and in vivo experiments were conducted to explore the mechanisms by which RPRD1B influences tumor growth and apoptosis. Results: RPRD1B expression was significantly elevated in DLBCL compared to normal tissues and was associated with poor prognosis. In vitro and in vivo experiments demonstrated that RPRD1B promoted lymphoma cell proliferation and inhibited apoptosis through the NF-κB signaling pathway. Conclusions: RPRD1B plays a critical role in the progression of DLBCL by modulating apoptosis and cellular proliferation. Targeting RPRD1B may offer a novel therapeutic strategy for DLBCL, suggesting its potential as a prognostic marker and therapeutic target in hematological malignancies.

SENP1 knockdown potentiates the apoptosis, cell cycle arrest, and reduces cisplatin resistance of diffuse large B cell lymphoma cells via inducing ferroptosis.

Ferroptosis has been regarded as a critical event in the process of diffuse large B cell lymphoma (DLBCL). Sentrin-specific protease 1 (SENP1) has emerged as an oncogene in multiple human malignancies. The present work was to investigate the effects of SENP1 on the progression of DLBCL and the possible regulatory mechanism involving ferroptosis. SENP1 expression in DLBCL tissues, parental and cisplatin-resistant DLBCL cells were, respectively, tested by GEPIA database, RT-qPCR, and Western blot. Cell viability was estimated via CCK-8 assay. Flow cytometry analysis estimated cell apoptosis and cycle. Western blot examined the expression of apoptosis-, cell cycle-, and ferroptosis-associated proteins. TBARS assay and BODIPY 581/591 C11 probe measured lipid peroxidation. Related assay kit assessed total iron levels. CCK-8 and flow cytometry evaluated cisplatin resistance. SENP1 expression was raised in DLBCL tissues and cells. SENP1 knockdown reduced cell viability, boosted cell apoptosis, cell cycle arrest, and elevated cisplatin sensitivity in DLBCL. SENP1 depletion drove the ferroptosis of both parental and cisplatin-resistant DLBCL cells and ferroptosis inhibitor Fer-1 reversed the influences of SENP1 inhibition on cell viability, apoptosis, cell cycle, and cisplatin resistance in DLBCL. Anyway, SENP1 absence might facilitate ferroptosis to obstruct the development of DLBCL and cisplatin resistance.

A novel anoikis-related signature predicts prognosis risk and treatment responsiveness in diffuse large B-cell lymphoma

ABSTRACT Background Although anoikis plays a role in cancer metastasis and aggressiveness, it has rarely been reported in diffuse large B cell lymphoma (DLBCL). Methods We obtained RNA sequencing data and matched clinical data from the GEO database. An anoikis-related genes (ARGs)-based risk signature was developed in GSE10846 training cohort and validated in three other cohorts. Additionally, we predicted half-maximal inhibitory concentration (IC50) of drugs based on bioinformatics method and obtained the actual IC50 to some chemotherapy drugs via cytotoxicity assay. Results The high-risk group, as determined by our signature, was associated with worse prognosis and an immunosuppressive environment in DLBCL. Meanwhile, the nomogram based on eight variables had more accurate ability in forecasting the prognosis than the international prognostic index in DLBCL. The prediction of IC50 indicated that DLBCL patients in the high-risk group were more sensitive to doxorubicin, IPA-3, lenalidomide, gemcitabine, and CEP.701, while patients in the low-risk group were sensitive to cisplatin and dasatinib. Consistent with the prediction, cytotoxicity assay suggested the higher sensitivity to doxorubicin and gemcitabine and the lower sensitivity to dasatinib in the high-risk group in DLBCL. Conclusion The ARG-based signature may provide a promising direction for prognosis prediction and treatment optimization for DLBCL patients.

Recombinant hirudin suppresses angiogenesis of diffuselarge B-cell lymphoma through regulation of the PAR-1-VEGF.

Hirudin is one of the specific inhibitors of thrombin, which has been confirmed to have strong bioactivities, including inhibiting tumors. However, the function and mechanism of hirudin and protease-activated receptor 1 (PAR-1) in diffuse large B-cell lymphoma (DLBCL) have not been clear. Detecting the expression PAR-1 in DLBCL tissues and cells by RT-qPCR and IHC. Transfected sh-NC, sh-PAR-1, or pcDNA3.1-PAR-1 in DLBCL cells or processed DLBCL cells through added thrombin, Vorapaxar, Recombinant hirudin (RH), or Na2S2O4 and co-culture with EA.hy926. And built DLBCL mice observed tumor growth. Detecting the expression of related genes by RT-qPCR, Western blot, IHC, and immunofluorescence, measured the cellular hypoxia with Hypoxyprobe-1 Kit, and estimated the cell inflammatory factors, proliferation, migration, invasion, and apoptosis by ELISA, CCK-8, flow cytometry, wound-healing and Transwell. Co-immunoprecipitation and pull-down measurement were used to verify the relationship. PAR-1 was highly expressed in DLBCL tissues and cells, especially in SUDHL2. Na2S2O4 induced SUDHL2 hypoxia, and PAR-1 did not influence thrombin-activated hypoxia. PAR-1 could promote SUDHL2 proliferation, migration, and invasion, and it was unrelated to cellular hypoxia. PAR-1 promoted proliferation, migration, and angiogenesis of EA.hy926 or SUDHL2 through up-regulation vascular endothelial growth factor (VEGF). RH inhibited tumor growth, cell proliferation, and migration, promoted apoptosis of DLBCL, and inhibited angiogenesis by down-regulating PAR-1-VEGF. RH inhibits proliferation, migration, and angiogenesis of DLBCL cells by down-regulating PAR-1-VEGF.

LncRNA CHROMR/miR-27b-3p/MET axis promotes the proliferation, invasion, and contributes to rituximab resistance in diffuse large B-cell lymphoma

Long non-coding RNAs (LncRNAs) could regulate chemoresistance through sponging microRNAs (miRNAs) and sequestering RNA binding proteins. However, the mechanism of lncRNAs in rituximab resistance in diffuse large B-cell lymphoma (DLBCL) is largely unknown. Here, we investigated the functions and molecular mechanisms of lncRNA CHROMR in DLBCL tumorigenesis and chemoresistance. LncRNA CHROMR is highly expressed in DLBCL tissues and cells. We examined the oncogenic functions of lncRNA CHROMR in DLBCL by a panel of gain-or-loss-of-function assays and in vitro experiments. LncRNA CHROMR suppression promotes CD20 transcription in DLBCL cells and inhibits rituximab resistance. RNA immunoprecipitation, RNA pull-down and dual luciferase reporter assay reveal that lncRNA CHROMR sponges with miR-27b-3p to regulate mesenchymal-epithelial transition factor (MET) levels and Akt signaling in DLBCL cells. Targeting the lncRNA CHROMR/miR-27b-3p/MET axis reduces DLBCL tumorigenesis. Altogether, these findings provide a new regulatory model, lncRNA CHROMR/miR-27b-3p/MET, which can serve as a potential therapeutic target for DLBCL.

Targeting HDACs for diffuse large B-cell lymphoma therapy

Histone deacetylases (HDACs) are involved in tumorigenesis and progression, however, their role in diffuse large B-cell lymphoma (DLBCL) is not well understood. In this study, we examined the expression levels, mutations, and clinical significance of HDACs in DLBCL. Additionally, we investigated the therapeutic potential of Chidamide, a novel HDAC inhibitor, to provide scientific evidence for targeting HDACs in DLBCL patients. We extracted transcriptome data of DLBCLs––including 47 lymph node samples and 337 whole-blood-cell controls––from The Cancer Genome Atlas. Bioinformatic analyses of HDAC expression, mutation, and correlation with the clinical significance of DLBCL patients were performed with the Gene Expression Profiling Interactive Analysis, GENEMANIA, and web-based software including cBioPortal and WebGestalt. To examine the therapeutic effect of Chidamide, DLBCL cell lines (WSU-DLCL-2 and DB cells) were employed. Cell proliferation and apoptosis were analyzed with Cell Counting Kit-8 and flow cytometry assays. The impact of Chidamide treatment was also analyzed by RNA sequencing of treated DB cells. Western blot was used to explore the molecular mechanism of the cytotoxicity of Chidamide on DLBCL cell lines. The expression of some HDACs (HDAC1, 2, 3, 4, 6, 7, 8, and 9) were significantly higher in the lymph node samples of DLBCL than that in whole-blood-cell controls. Moreover, we found that the mutation rate of HDACs was also higher in DLBCL tissues, although the overall survival of DLBCL patients was not associated with HDAC expression. Chidamide was found to have a cytotoxic effect on DLBCL cells in a dose-dependent manner, while transcriptome analysis and western blot revealed that using it for treatment impacted several biological processes, including PI3K/AKT signaling, mTOR signaling, the cell cycle, and apoptosis pathways. Alterations of HDAC genes, including enhanced expression and mutations, are positively related to DLBCL. Targeting HDACs with specific inhibitors such as Chidamide may represent a potential therapeutic approach for DLBCL patients.

CD70 is a potential prognostic marker and significantly regulates cellular function in diffuse large B-cell lymphoma.

Extensive research has demonstrated that dysregulation of costimulatory molecule expression plays a pivotal role in cancer biology. However, the impact of intratumoral CD70 on the initiation, progression, and immune response in diffuse large B-cell lymphoma (DLBCL) remains poorly understood. This study aims to elucidate the clinical significance of CD70 in DLBCL diagnosis and prognosis, as well as its relationship with the immune microenvironment. We first analyzed CD70 expression across various cancers, including DLBCL, using multiple online databases (TIMER, GEPIA, GENT2, TNMPlot, GSCA, and GEO). We then evaluated the clinical correlations and prognostic value of CD70 in DLBCL. Additionally, we investigated the functional role of CD70 in DLBCL cells. Genomic alterations of CD70 were analyzed using the cBioPortal online tool. Co-expression network analysis was performed to assess the biological functions associated with CD70. Furthermore, we utilized TIMER2.0 to examine the correlation between CD70 expression and immune cell infiltration. Our results revealed that CD70 expression was significantly upregulated in DLBCL tissues compared to matched normal tissues, and high CD70 expression was associated with poor clinical outcomes in DLBCL patients. In vitro experiments demonstrated that CD70 inhibition promotes apoptosis and induces G1 phase arrest in DLBCL cells. Genomic alteration analysis showed that patients with CD70 alterations exhibited worse overall survival compared to those without such alterations. Co-expression and functional enrichment analyses indicated that CD70 is functionally related to tumor necrosis factor receptor binding and the NF-κB signaling pathway. Moreover, we found that CD70 expression levels were negatively correlated with B cell and NK cell infiltration in DLBCL. In conclusion, this study suggests that CD70 is a potential diagnostic and therapeutic biomarker for DLBCL. Our findings provide valuable insights for the development of novel therapeutic strategies targeting CD70 in DLBCL treatment.

Analysis and Investigation of Bioinformatics and Epigenetics Reveal the Underlying Mechanisms by which FLOT2 Modulates the Progression of Diffuse Large B-cell Lymphoma.

Diffuse large B-cell lymphoma (DLBCL) poses a significant threat to the quality of life for people worldwide. Regrettably, effective treatment strategies for this disease remain elusive in clinical practice due to the unclear understanding of its molecular mechanisms. Therefore, this study was devised to address these issues and identify novel diagnostic, therapeutic, and prognostic biomarkers for DLBCL. Gene expression and clinical data for DLBCL patients were retrieved from The Cancer Genome Atlas (TCGA) database, and relevant clinical data, tumor mutational burden (TMB), and gene expression levels were extracted. Bioinformatics analysis was conducted to screen for differentially expressed genes (DEGs). The prognostic significance of flotillin-2 (FLOT2) was assessed using Kaplan-Meier survival analysis. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analyses were employed to evaluate mRNA and protein levels of the genes. Cell proliferation, apoptosis, and invasion were assessed using cell counting kit-8 (CCK-8) assay, flow cytometry analysis, and Transwell assay, respectively. Our bioinformatics analysis revealed that FLOT2 was significantly overexpressed in DLBCL tissues compared to normal tissues, a finding corroborated by subsequent immunohistochemistry staining, qRT-PCR, and Western blot analyses. To elucidate its biological functions, shRNAs targeting FLOT2 were transfected into DLBCL cell lines (LY-3 and U2932), resulting in suppressed cell proliferation and invasion, while promoting apoptosis. Furthermore, a positive correlation between TMB and FLOT2 expression in DLBCL was observed. Subsequently, quanTIseq was utilized to calculate the immune score and assess FLOT2 gene expression. In DLBCL, FLOT2 gene expression was found to be associated with T cell CD4+ (non-regulatory) (p < 0.01), monocytes (p < 0.05), and uncharacterized cells (p < 0.05). Regarding immune checkpoint markers, including the cluster of differentiation 274 (CD274), cytotoxic T lymphocyte-associated antigen-4 (CTLA4), hepatitis A virus cellular receptor 2 (HAVCR2), lymphocyte activation gene-3 (LAG3), programmed cell death protein 1 (PDCD1), programmed cell death 1 ligand 2 (PDCD1LG2), Siglec-15 (SIGLEC15), and T cell immunoreceptor with Ig and ITIM domains (TIGIT), our analysis indicated that in DLBCL, FLOT2 exhibited a relationship only with TIGIT (p < 0.05). In summary, FLOT2 functions as an oncogene and is linked to DLBCL prognosis and the tumor microenvironment. Targeting FLOT2 deletion emerges as a novel strategy to impede DLBCL aggressiveness by inhibiting cell proliferation and invasion, ultimately inducing apoptotic cell death.

Identifying CD1c as a potential biomarker by the comprehensive exploration of tumor mutational burden and immune infiltration in diffuse large B cell lymphoma.

Tumor mutational burden (TMB) is a valuable prognostic biomarker. This study explored the predictive value of TMB and the potential association between TMB and immune infiltration in diffuse large B-cell lymphoma (DLBCL). We downloaded the gene expression profile, somatic mutation, and clinical data of DLBCL patients from The Cancer Genome Atlas (TCGA) database. We classified the samples into high-and low-TMB groups to identify differentially expressed genes (DEGs). Functional enrichment analyses were performed to determine the biological functions of the DEGs. We utilized the cell-type identification by estimating relative subsets of RNA transcripts (CIBERSORT) algorithm to estimate the abundance of 22 immune cells, and the significant difference was determined by the Wilcoxon rank-sum test between the high- and low-TMB group. Hub gene had been screened as the prognostic TMB-related immune biomarker by the combination of the Immunology Database and Analysis Portal (ImmPort) database and the univariate Cox analysis from the Gene Expression Omnibus (GEO) database including six DLBCL datasets. Various database applications such as Tumor Immune Estimation Resource (TIMER), CellMiner, konckTF, and Genotype-Tissue Expression (GTEx) verified the functions of the target gene. Wet assay confirmed the target gene expression at RNA and protein levels in DLBCL tissue and cell samples. Single nucleotide polymorphism (SNP) occurred more frequently than insertion and deletion, and C > T was the most common single nucleotide variant (SNV) in DLBCL. Survival analysis showed that the high-TMB group conferred poor survival outcomes. A total of 62 DEGs were obtained, and 13 TMB-related immune genes were identified. Univariate Cox analysis results illustrated that CD1c mutation was associated with lower TMB and manifested a satisfactory clinical prognosis by analysis of large samples from the GEO database. In addition, infiltration levels of immune cells in the high-TMB group were lower. Using the TIMER database, we systematically analyzed that the expression of CD1c was positively correlated with B cells, neutrophils, and dendritic cells and negatively correlated with CD8+ T cells, CD4+ T cells, and macrophages. Drug sensitivity showed a significant positive correlation between CD1c expression level and clinical drug sensitivity from the CellMiner database. CREB1, AHR, and TOX were used to comprehensively explore the regulation of CD1c-related transcription factors and signaling pathways by the KnockTF database. We searched the GETx database to compare the mRNA expression levels of CD1c between DLBCL and normal tissues, and the results suggested a significant difference between them. Moreover, wet experiments were conducted to verify the high expression of CD1c in DLBCL at the RNA and protein levels. Higher TMB correlated with poor survival outcomes and inhibited the immune infiltrates in DLBCL. Our results suggest that CD1c is a TMB-related prognostic biomarker.

Unraveling the enigma of B cells in diffuse large B-cell lymphoma: unveiling cancer stem cell-like B cell subpopulation at single-cell resolution.

Diffuse large B-cell lymphoma (DLBCL) represents the most prevalent form of aggressive non-Hodgkin lymphoma. Despite receiving standard treatment, a subset of patients undergoes refractory or recurrent cases, wherein the involvement of cancer stem cells (CSCs) could be significant. We comprehensively characterized B cell subpopulations using single-cell RNA sequencing data from three DLBCL samples and one normal lymph tissue. The CopyKat R package was employed to assess the malignancy of B cell subpopulations based on chromosomal copy number variations. CIBERSORTx software was utilized to estimate the proportions of B cell subpopulations in 230 DLBCL tissues. Furthermore, we employed the pySCENIC to identify key transcription factors that regulate the functionality of B cell subpopulations. By employing CellphoneDB, we elucidated the interplay among tumor microenvironment components within the B cell subpopulations. Finally, we validated our findings through immunofluorescence experiments. Our analysis revealed a specific cancer stem cell-like B cell subpopulation exhibiting self-renewal and multilineage differentiation capabilities based on the exploration of B cell subpopulations in DLBCL and normal lymph tissues at the single-cell level. Notably, a high infiltration of cancer stem cell-like B cells correlated with a poor prognosis, potentially due to immune evasion mediated by low expression of major histocompatibility complex molecules. Furthermore, we identified key transcription factor regulatory networks regulated by HMGB3, SAP30, and E2F8, which likely played crucial roles in the functional characterization of the cancer stem cell-like B cell subpopulation. The existence of cancer stem cell-like B cells in DLBCL was validated through immunofluorescent staining. Finally, cell communication between B cells and tumor-infiltrating T cell subgroups provided further insights into the functional characterization of the cancer stem cell-like B cell subpopulation. Our research provides a systematic description of a specific cancer stem cell-like B cell subpopulation associated with a poor prognosis in DLBCL. This study enhances our understanding of CSCs and identifies potential therapeutic targets for refractory or recurrent DLBCL patients.

The Characterization and Prognostic Value of Tumor Immune Microenvironment in Diffuse Large B-Cell Lymphoma

Introduction: Diffuse large B-cell lymphoma (DLBCL) is featured by high heterogeneity, especially in clinical outcome. Tumor microenvironment (TME) represents a complex ecosystem around tumor cells, which has been found to be associated with the prognosis of DLBCL patients. However, the overall profile of TME immune components, perception of its correlation with tumor development and molecular mechanism are still insufficient in DLBCL. Here, we aimed to investigate novel prognostic scoring system and biomarkers based on TME immune components, and explore their underlying molecular mechanism in the development of DLBCL. Methods: Microarray transcriptomic data and corresponding clinical information of DLBCL patients (n=946) from GSE23501, GSE53786, GSE10846, GSE136971, GSE57611 and GSE32918 in GEO database were analyzed. The immune composition was calculated by CIBERSORT. Immunohistochemistry (IHC) was used to assess the expression level of CD2 in DLBCL tissues. Seurat in R was employed for conducting single-cell analysis. The study was performed with the approval of the Medical Ethical Committee of Shandong Provincial Hospital, and all samples were collected with informed consents. Results: To assess the immune cell composition of TME in DLBCL patients, we conducted a comprehensive analysis of the relative proportions of 22 distinct immune cell types within DLBCL TME. Subsequently, the prognostic role of TME immune components in DLBCL patients was probed, and a novel TME immune score based on the proportion of 22 immune cells was established. Furthermore, to evaluate the association between TME immune score and clinical prognosis in DLBCL patients, we performed K-M analysis and 3,5,10-year ROC analysis, which revealed the high prognostic efficacy of TME immune score. Higher TME immune scores were demonstrated to be significantly associated with worse prognosis, which was subsequently validated in an external cohort containing 230 DLBCL patients. Survival data of quartile subgroups also unveiled the prognostic value of TME immune score in DLBCL patients ( Fig. 1A). We further explored the correlation between TME immune score and clinical pathological features in DLBCL patients. Higher TME immune scores were observed to be correlated with more advanced Ann Arbor stage, non-germinal center B-cell-like subtype, lower expression levels of immune checkpoint molecules (CTLA-4, PD-1, PD-L2), decreased ESTIMATE stromal and immune scores, as well as higher tumor purity, indicating that the TME immune score may enable the prediction of treatment response to immune checkpoint inhibitors. The potential molecular mechanism of TME modulation in DLBCL development was further explored. Results of GO and KEGG enrichment illuminated that differential expression genes (DEGs) in two groups were significantly enriched in the anti-tumor immunity related processes and pathways, especially T-cell receptor activation. Subsequently, 6 hub genes (CCL5, CD2, CD3E, MMP9, CCR5, GATA3) in protein-protein interaction network constructed by DEGs were identified, whose expression levels were found to be associated with prognosis in DLBCL patients. Moreover, IHC was used to investigate the relevance of CD2 protein expression with prognosis in DLBCL patients. The expression of CD2 protein was found to be associated with poor prognosis in DLBCL patients ( Fig. 1A). To further investigate the regulatory function of CD2 in the immune microenvironment of DLBCL, we conducted single-cell analysis based on three DLBCL patients, and revealed that CD2 was prominently expressed in T cell subpopulation and was correlated with different differentiation trajectory of T cells in DLBCL. Subsequent differential gene analysis revealed that DEGs between state 1 and state 2, 3 were significantly enriched in KEGG pathways including antigen presentation and Th cell differentiation ( Fig. 1B), suggesting the role of CD2 in T cell activation and differentiation. Conclusions: Taken together, we established a novel TME immune score which could serve as a prognostic indicator in DLBCL patients. More importantly, we identified CD2 as a prognostic biomarker in DLBCL patients and unveiled its association with different T-cell activation states. Our study might provide a novel prognostic stratification strategy and promising biomarkers, which could facilitate the individualized management in DLBCL patients.

NCAPD3 Prompts Diffuse Large B-Cell Lymphoma Progression through Modulating SIRT1 Expression in H3K9 Monomethylation-Dependent Manner

Chromosomal instability, including number and structure abnormality, is the critical molecular basis in lymphoid oncogenesis. Condensin, a family of structural maintenance of chromosome complexes, has been shown to regulate chromosome compaction and segregation during mitosis. NCAPD3, a HEAT-repeat subunit of condensin II, plays a dominant role in condensin-mediated chromosome dynamics, whose abnormalities are related to tumorigenesis and developmental disorders but remain unexplored in lymphoma. This study aims to unravel the expression, molecular function and mechanism of NCAPD3 in diffuse large B-cell lymphoma (DLBCL). We first elucidated the expression of NCAPD3 in DLBCL. Lymph node tissues from 70 DLBCL patients and 35 reactive hyperplasia cases were collected with informed consent approved by the Medical Ethical Committee of Shandong Provincial Hospital. Higher NCAPD3 expression was identified in DLBCL tissues and correlated with advanced Ann Arbor stage and higher IPI score. The survival analysis presented patients with higher NCAPD3 suffered shorter survival (P=0.045). Meanwhile, upregulation of NCAPD3 was validated in DLBCL cells compared with normal CD19+ B-cell. We further explored the biological functions of NCAPD3 in DLBCL and constructed NCAPD3-knockdown, knockout and overexpression models. Deficiency of NCAPD3 impeded cell proliferation, induced apoptosis and increased the sensitivity to doxorubicin and ibrutinib. Instead, NCAPD3 overexpression facilitated cell proliferation and therapeutic resistance. In vivo experiments further indicated that xenograft DLBCL mice with deficient NCAPD3 presented delayed tumor growth. These suggested NCAPD3 promoted DLBCL progression. Strikingly, we found knocking down NCAPD3 disturbed the mitosis, triggering the formation of aneuploidy, due to its function in chromatin structure and dynamics. Hence, we further portrayed the transformation of chromosome architecture under different NCAPD3 expression. Chromosome spreads exhibited chromosomes became slim and elongated upon NCAPD3 overexpression, instead, NCAPD3 knockout triggered short and highly-curled transformation with the global upregulation of H3K4me3, an indication of transcriptional activation and chromatin decompaction (Figure 1). This suggested NCAPD3 could modulate transcriptional activity. Therewith, we investigated how NCAPD3 regulated gene transcription. We examined the interacting proteins of NCAPD3 by mass spectrometry and Clusters of Orthologous Groups analysis revealed they were mainly enriched in RNA processing and modification, chromatin dynamics and cell cycle control. Of them, transcription factor, GTF2I, may be responsible for NCAPD3-mediated transcription regulation. Coimmunoprecipitation (co-IP) verified their interaction and chromatin immunoprecipitation (ChIP) presented they were both located on the promoter of target gene, SIRT1. We further examined SIRT1 expression after regulating NCAPD3 expression, showing a significantly positive correlation. This suggested NCAPD3 could support SIRT1 transcription via being anchored by GTF2I on the promoter of SIRT1. We further elucidated the potential mechanism how NCAPD3 regulated SIRT1 expression. Previous study found that NCAPD3 could interact with histone methylation markers in mammalian genome, thus, we explored whether NCAPD3 could modulate the SIRT1 expression via recognizing the histone methylation marker on SIRT1 promoter. Co-IP assay identified the interaction between NCAPD3 and monomethylation of lysine residue K9 of histone H3 (H3K9me1), an active promoter tag, in DLBCL and ChIP assay verified the location of H3k9me1 on SIRT1 promoter. When NCAPD3 downregulated, H3K9me1 on SIRT promoter diminished, ruining the transcription of SIRT. To clarify whether the oncogenic effects of NCAPD3 was mediated by SIRT1, we conducted functional reversion assays, showing regulating SIRT1 partially reversed the effects of NCAPD3. The above suggested NCAPD3 prompted DLBCL progression through modulating SIRT expression in H3k9me1-mediated manner. In conclusion, this study unraveled that dysregulation of NCAPD3 could disturb chromosome compaction and segregation, induce genome instability and alter the transcription of SIRT1 via modulating H3k9 monomethylation, which provided novel insights into NCAPD3-based targeting strategy for DLBCL.

Long non-coding RNA SNHG17 may function as a competitive endogenous RNA in diffuse large B-cell lymphoma progression by sponging miR-34a-5p.

We investigated the functional mechanism of long non-coding small nucleolar host gene 17 (SNHG17) in diffuse large B-cell lymphoma (DLBCL). lncRNAs related to the prognosis of patients with DLBCL were screened to analyze long non-coding small nucleolar host gene 17 (SNHG17) expression in DLBCL and normal tissues, and a nomogram established for predicting DLBCL prognosis. SNHG17 expression in B-cell lymphoma cells was detected using qPCR. The effects of SNHG17 with/without doxorubicin on the proliferation and apoptosis of DoHH2 and Daudi were detected. The effects of combined SNHG17 and doxorubicin were analyzed. The regulatory function of SNHG17 in DLBCL was investigated using a mouse tumor xenotransplantation model. RNA sequencing was used to analyze the signaling pathways involved in SNHG17 knockdown in B-cell lymphoma cell lines. The target relationships among SNHG17, microRNA, and downstream mRNA biomolecules were detected. A higher SNHG17 level predicted a lower survival rate. SNHG17 was highly expressed in DLBCL patient tissues and cell lines. We established a prognostic model containing SNHG17 expression, which could effectively predict the overall survival rate of DLBCL patients. SNHG17 knockdown inhibited the proliferation and induced the apoptosis of B-cell lymphoma cells, and the combination of SNHG17 and doxorubicin had a synergistic effect. SNHG17, miR-34a-5p, and ZESTE gene enhancer homolog 2 (EZH2) had common hypothetical binding sites, and the luciferase reporter assay verified that miR-34a-5p was the direct target of SNHG17, and EZH2 was the direct target of miR-34a-5p. The carcinogenic function of SNHG17 in the proliferation and apoptosis of DLBCL cells was partially reversed by a miR-34a-5p inhibitor. SNHG17 increases EZH2 levels by inhibiting miR-34a-5p. Our findings indicate SNHG17 as critical for promoting DLBCL progression by regulating the EZH2 signaling pathway and sponging miR-34a-5p. These findings provide a new prognostic marker and therapeutic target for the prognosis and treatment of DLBCL.

Blockade of PD-1 and LAG-3 expression on CD8+ T cells promotes the tumoricidal effects of CD8+ T cells.

The diffuse large B-cell lymphoma (DLBCL) has the highest incidence of all lymphomas worldwide. To investigate the functions of lymphocyte activation gene 3 (LAG-3) and programmed cell death 1 (PD-1) in tissues and peripheral blood of patients with DLBCL, the expression of LAG-3 and PD-1 genes in DLBCL-TCGA were analyzed. LAG-3 and PD-1 mRNA levels in DLBCL were analyzed using data from The Cancer Genome Atlas (TCGA) database. Utilize the Genotype-Tissue Expression (GTEx) database for assessing the variance in the expression of LAG-3, PD-1, and other associated factors between the tissues of DLBCL patients and healthy individuals. Immunohistochemistry was applied to detect the expression of LAG-3 and PD-1 levels in 137 cases of DLBCL tissues and 20 cases of reactive lymphoid hyperplasia. The prognostic value of LAG-3 and PD-1 were assessed using the Kaplan-Meier curve. The Estimation of Stromal and Immune cells in Malignant Tumor tissues using Expression data (ESTIMATE) and ssGSEA algorithm were used to explore the immune microenvironment of DLBCL. Additionally, the expression and co-expression of LAG-3 and PD-1 were detected on CD4 and CD8 T cells in peripheral blood samples from 100 cases of DLBCL tissues and 30 cases of healthy individuals using flow cytometry. According to TCGA database, LAG-3 and PD-1 gene expression levels were significantly up-regulated in DLBCL tissues. LAG-3 and PD-1 levels were also strongly positively correlated with those of most infiltrating immune cells. Overall survival of patients with high LAG-3 and PD-1 co-expression was significantly shorter than that of patients with low co-expression. In DLBCL patients, LAG-3 and PD-1 were highly expressed in peripheral blood CD8+ T cells. In addition, LAG-3 was highly expressed in CD4+ T cells, while the expression of PD-1 in CD4+ T cells of DLBCL patients showed no significant difference compared to healthy individuals. Additionally, CD8+ T cells and SU-DHL6/OCI-LY3 from patients with DLBCL were co-cultured in vitro; after addition of LAG-3 and/or PD-1 inhibitors alone, an increased perforin and granzyme B secretion levels by CD8+ T cells were detected, as well as an increase in the overall proportion of tumor cells undergoing apoptosis. High LAG-3 and PD-1 levels significantly inhibit CD8+ T cell function, resulting in weakened ability to kill tumor cells. Combined LAG-3 and PD-1 blockade can restore CD8+ T cell function and provides a potential avenue for development of personalized cellular immunotherapy for DLBCL.

PAQR3 facilitates the ferroptosis of diffuse large B-cell lymphoma via the regulation of LDLR-mediated PI3K/AKT pathway.

Progesterone and adiponectin receptor 3 (PAQR3) has been found to regulate tumor progression by mediating cell ferroptosis. However, whether PAQR3 mediates ferroptosis in diffuse large B-cell lymphoma (DLBCL) needs further investigation. The mRNA and protein levels of PAQR3 and low-density lipoprotein receptor (LDLR) were assessed by qRT-PCR and WB assays. Cell proliferation was detected by MTT assay and EdU assay. Shrunken mitochondria was counted under transmission electron microscope. Cell ferroptosis was evaluated by measuring the levels of malondialdehyde, reactive oxygen species, glutathione, Fe2+ , and the protein expression of ferroptosis-related markers. PAQR3 and LDLR interaction was confirmed by RIP assay and pull-down assay. Our study showed that PAQR3 was underexpressed, while LDLR was overexpressed in DLBCL tissues and cells. Functionally, PAQR3 overexpression or LDLR knockdown restrained DLBCL cell proliferation and enhanced ferroptosis. Mechanistically, PAQR3 reduced LDLR expression by inhibiting its mRNA stability. Meanwhile, LDLR overexpression reversed PAQR3-mediated the promoting on DLBCL cell ferroptosis, and LY294002 (PI3K/AKT inhibitor) eliminated the inhibiting effects of LDLR overexpression on DLBCL cell ferroptosis. Additionally, excessive PAQR3 reduced DLBCL tumor growth by enhancing tumor cell ferroptosis through LDLR-mediated PI3K/AKT pathway. In conclusion, our data suggested that PAQR3 restrained DLBCL progression by aggravating ferroptosis, which was achieved by inhibiting LDLR expression to repress PI3K/AKT pathway.