Targeting the polarization of tumor-associated macrophages and modulating mir-155 expression might be a new approach to treat diffuse large B-cell lymphoma of the elderly

Presence of Epstein-Barr virus (EBV) antigens detected by sensitive methods has no influence on local immune environment in diffuse large B cell lymphoma

EBV+ diffuse large B cell lymphoma (DLBCL) not otherwise specified (NOS) is a new entity confirmed by the World Health Organization (WHO) in 2017. In this new entity, the virus may contribute to a tolerogenic microenvironment. Traces of the virus have been described in DLBCL with more sensitive methods, in cases that were originally diagnosed as negative. The aim of this study was to analyze the expression of immune response genes in the tumor microenvironment to disclose the role of the virus and its traces in DLBCL. In 48 DLBCL cases, the expression of immune response genes and the presence of molecules that induce tolerance, such as TIM3, LAG3 and PDL1 by immunohistochemistry (IHC), were studied. To broaden the study of the microenvironment, tumor-associated macrophages (TMAs) were also explored. No significant differences were observed in the expression of immune response genes in the EBV+ DLBCL and those cases that were EBV- DLBCL but that exhibited viral traces, assessed by ViewRNA assay. Only the EBV+ DLBCL cases displayed a significantly higher increase in the expression of CD8 and cytotoxic T cells detected by gene expression analysis, and of PDL1 in tumor cells and in the expression of CD68 in the tumor microenvironment detected by IHC, not observed in those cases with viral traces. The increase in CD8 and cytotoxic T cells, PDL1 and CD68 markers only in EBV+ DLBCL may indicate that traces of viral infection might not have influence in immune response markers.

Potential Pathogenic Impact of Cow’s Milk Consumption and Bovine Milk-Derived Exosomal MicroRNAs in Diffuse Large B-Cell Lymphoma

Epidemiological evidence supports an association between cow’s milk consumption and the risk of diffuse large B-cell lymphoma (DLBCL), the most common non-Hodgkin lymphoma worldwide. This narrative review intends to elucidate the potential impact of milk-related agents, predominantly milk-derived exosomes (MDEs) and their microRNAs (miRs) in lymphomagenesis. Upregulation of PI3K-AKT-mTORC1 signaling is a common feature of DLBCL. Increased expression of B cell lymphoma 6 (BCL6) and suppression of B lymphocyte-induced maturation protein 1 (BLIMP1)/PR domain-containing protein 1 (PRDM1) are crucial pathological deviations in DLBCL. Translational evidence indicates that during the breastfeeding period, human MDE miRs support B cell proliferation via epigenetic upregulation of BCL6 (via miR-148a-3p-mediated suppression of DNA methyltransferase 1 (DNMT1) and miR-155-5p/miR-29b-5p-mediated suppression of activation-induced cytidine deaminase (AICDA) and suppression of BLIMP1 (via MDE let-7-5p/miR-125b-5p-targeting of PRDM1). After weaning with the physiological termination of MDE miR signaling, the infant’s BCL6 expression and B cell proliferation declines, whereas BLIMP1-mediated B cell maturation for adequate own antibody production rises. Because human and bovine MDE miRs share identical nucleotide sequences, the consumption of pasteurized cow’s milk in adults with the continued transfer of bioactive bovine MDE miRs may de-differentiate B cells back to the neonatal “proliferation-dominated” B cell phenotype maintaining an increased BLC6/BLIMP1 ratio. Persistent milk-induced epigenetic dysregulation of BCL6 and BLIMP1 expression may thus represent a novel driving mechanism in B cell lymphomagenesis. Bovine MDEs and their miR cargo have to be considered potential pathogens that should be removed from the human food chain.

Insights into the tumor microenvironment of B cell lymphoma

The standard therapies in lymphoma have predominantly focused on targeting tumor cells with less of a focus on the tumor microenvironment (TME), which plays a critical role in favoring tumor growth and survival. Such an approach may result in increasingly refractory disease with progressively reduced responses to subsequent treatments. To overcome this hurdle, targeting the TME has emerged as a new therapeutic strategy. The TME consists of T and B lymphocytes, tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), cancer-associated fibroblasts (CAFs), and other components. Understanding the TME can lead to a comprehensive approach to managing lymphoma, resulting in therapeutic strategies that target not only cancer cells, but also the supportive environment and thereby ultimately improve survival of lymphoma patients. Here, we review the normal function of different components of the TME, the impact of their aberrant behavior in B cell lymphoma and the current TME-direct therapeutic avenues.

GATA3 Inhibits Viral Infection by Promoting MicroRNA-155 Expression

Recognition of viral RNAs by melanoma differentiation associated gene-5 (MDA5) initiates chicken antiviral response by producing type I interferons. Our previous studies showed that chicken microRNA-155-5p (gga-miR-155-5p) enhanced IFN-β expression and suppressed the replication of infectious burse disease virus (IBDV), a double-stranded RNA (dsRNA) virus causing infectious burse disease in chickens. However, the mechanism underlying IBDV-induced gga-miR-155-5p expression in host cells remains elusive. Here, we show that IBDV infection or poly(I:C) treatment of DF-1 cells markedly increased the expression of GATA-binding protein 3 (GATA3), a master regulator for TH2 cell differentiation, and that GATA3 promoted gga-miR-155-5p expression in IBDV-infected or poly(I:C)-treated cells by directly binding to its promoter. Surprisingly, ectopic expression of GATA3 significantly reduced IBDV replication in DF-1 cells, and this reduction could be completely abolished by treatment with gga-miR-155-5p inhibitors, whereas knockdown of GATA3 by RNA interference enhanced IBDV growth, and this enhancement could be blocked with gga-miR-155-5p mimics, indicating that GATA3 suppressed IBDV replication by gga-miR-155-5p. Furthermore, our data show that MDA5 is required for GATA3 expression in host cells with poly(I:C) treatment, so are the adaptor protein TBK1 and transcription factor IRF7, suggesting that induction of GATA3 expression in IBDV-infected cells relies on MDA5-TBK1-IRF7 signaling pathway. These results uncover a novel role for GATA3 as an antivirus transcription factor in innate immune response by promoting miR-155 expression, further our understandings of host response against pathogenic infection, and provide valuable clues to the development of antiviral reagents for public health. IMPORTANCE Gga-miR-155-5p acts as an important antivirus factor against IBDV infection, which causes a severe immunosuppressive disease in chicken. Elucidation of the mechanism regulating gga-miR-155-5p expression in IBDV-infected cells is essential to our understandings of the host response against pathogenic infection. This study shows that transcription factor GATA3 initiated gga-miR-155-5p expression in IBDV-infected cells by directly binding to its promoter, suppressing viral replication. Furthermore, induction of GATA3 expression was attributable to the recognition of dsRNA by MDA5, which initiates signal transduction via TBK1 and IRF7. Thus, it is clear that IBDV induces GATA3 expression via MDA5-TBK1-IRF7 signaling pathway, thereby suppressing IBDV replication by GATA3-mediated gga-miR-155-5p expression. This information remarkably expands our knowledge of the roles for GATA3 as an antivirus transcription factor in host innate immune response particularly at an RNA level and may prove valuable in the development of antiviral drugs for public health.

High Counts of CD68+ and CD163+ Macrophages in Mantle Cell Lymphoma Are Associated With Inferior Prognosis

Background

Lymphoma-associated macrophages (LAMs) are key components in the lymphoma microenvironment, which may impact disease progression and response to therapy. There are two major subtypes of LAMs, CD68+ M1 and CD163+ M2. M2 LAMs can be transformed from M1 LAMs, particularly in certain diffuse large B-cell lymphomas (DLBCL). While mantle cell lymphoma (MCL) is well-known to contain frequent epithelioid macrophages, LAM characterization within MCL has not been fully described. Herein we evaluate the immunophenotypic subclassification, the expression of immune checkpoint molecule PD-L1, and the prognostic impact of LAMs in MCL.

Materials and Methods

A total of 82 MCL cases were collected and a tissue microarray block was constructed. Immunohistochemical staining was performed using CD68 and CD163, and the positive cells were recorded manually in four representative 400× fields for each case. Multiplexed quantitative immunofluorescence assays were carried out to determine PD-L1 expression on CD68+ M1 LAMs and CD163+ M2 LAMs. In addition, we assessed Ki67 proliferation rate of MCL by an automated method using the QuPath digital imaging analysis. The cut-off points of optimal separation of overall survival (OS) were analyzed using the X-Tile software, the SPSS version 26 was used to construct survival curves, and the log-rank test was performed to calculate the p-values.

Results

MCL had a much higher count of M1 LAMs than M2 LAMs with a CD68:CD163 ratio of 3:1. Both M1 and M2 LAMs were increased in MCL cases with high Ki67 proliferation rates (>30%), in contrast to those with low Ki67 (<30%). Increased number of M1 or M2 LAMs in MCL was associated with an inferior OS. Moreover, high expression of PD-L1 on M1 LAMs had a slightly better OS than the cases with low PD-L1 expression, whereas low expression of PD-L1 on M2 LAMs had a slightly improved OS, although both were not statistically significant.

Conclusions

In contrast to DLBCL, MCL had a significantly lower rate of M1 to M2 polarization, and the high levels of M1 and M2 LAMs were associated with poor OS. Furthermore, differential PD-L1 expressions on LAMs may partially explain the different functions of tumor-suppressing or tumor-promoting of M1 and M2 LAMs, respectively.

Targeting the tumor microenvironment in B-cell lymphoma: challenges and opportunities

B-cell lymphoma is a group of hematological malignancies with high clinical and biological heterogeneity. The pathogenesis of B-cell lymphoma involves a complex interaction between tumor cells and the tumor microenvironment (TME), which is composed of stromal cells and extracellular matrix. Although the roles of the TME have not been fully elucidated, accumulating evidence implies that TME is closely relevant to the origination, invasion and metastasis of B-cell lymphoma. Explorations of the TME provide distinctive insights for cancer therapy. Here, we epitomize the recent advances of TME in B-cell lymphoma and discuss its function in tumor progression and immune escape. In addition, the potential clinical value of targeting TME in B-cell lymphoma is highlighted, which is expected to pave the way for novel therapeutic strategies.

Tumor-Associated Macrophages in Hepatocellular Carcinoma: Friend or Foe?

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide, and it has diverse etiologies with multiple mechanisms. The diagnosis of HCC typically occurs at advanced stages when there are limited therapeutic options. Hepatocarcinogenesis is considered a multistep process, and hepatic macrophages play a critical role in the inflammatory process leading to HCC. Emerging evidence has shown that tumor-associated macrophages (TAMs) are crucial components defining the HCC immune microenvironment and represent an appealing option for disrupting the formation and development of HCC. In this review, we summarize the current knowledge of the polarization and function of TAMs in the pathogenesis of HCC, as well as the mechanisms underlying TAM-related anti-HCC therapies. Eventually, novel insights into these important aspects of TAMs and their roles in the HCC microenvironment might lead to promising TAM-focused therapeutic strategies for HCC.

Comprehensive Characterization of Cachexia-Inducing Factors in Diffuse Large B-Cell Lymphoma Reveals a Molecular Subtype and a Prognosis-Related Signature

Background

Cachexia is defined as an involuntary decrease in body weight, which can increase the risk of death in cancer patients and reduce the quality of life. Cachexia-inducing factors (CIFs) have been reported in colorectal cancer and pancreatic adenocarcinoma, but their value in diffuse large B-cell lymphoma (DLBCL) requires further genetic research.

Methods

We used gene expression data from Gene Expression Omnibus to evaluate the expression landscape of 25 known CIFs in DLBCL patients and compared them with normal lymphoma tissues from two cohorts [GSE56315 (n = 88) and GSE12195 (n = 136)]. The mutational status of CIFs were also evaluated in The Cancer Genome Atlas database. Based on the expression profiles of 25 CIFs, a single exploratory dataset which was merged by the datasets of GSE10846 (n = 420) and GSE31312 (n = 498) were divided into two molecular subtypes by using the method of consensus clustering. Immune microenvironment between different subtypes were assessed via single-sample gene set enrichment analysis and the CIBERSORT algorithm. The treatment response of commonly used chemotherapeutic drugs was predicted and gene set variation analysis was utilized to reveal the divergence in activated pathways for distinct subtypes. A risk signature was derived by univariate Cox regression and LASSO regression in the merged dataset (n = 882), and two independent cohorts [GSE87371 (n = 221) and GSE32918 (n = 244)] were used for validation, respectively.

Results

Clustering analysis with CIFs further divided the cases into two molecular subtypes (cluster A and cluster B) associated with distinct prognosis, immunological landscape, chemosensitivity, and biological process. A risk-prognostic signature based on CCL2, CSF2, IL15, IL17A, IL4, TGFA, and TNFSF10 for DLBCL was developed, and significant differences in overall survival analysis were found between the low- and high-risk groups in the training dataset and another two independent validation datasets. Multivariate regression showed that the risk signature was an independently prognostic factor in contrast to other clinical characteristics.

Conclusion

This study demonstrated that CIFs further contribute to the observed heterogeneity of DLBCL, and molecular classification and a risk signature based on CIFs are both promising tools for prognostic stratification, which may provide important clues for precision medicine and tumor-targeted therapy.

GM-CSF enhanced the effect of CHOP and R-CHOP on inhibiting diffuse large B-cell lymphoma progression via influencing the macrophage polarization

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is a common type of the Non-Hodgkin lymphomas (NHLs) formed by the neoplastic transformation of mature B cells. As the first-line therapeutics, CHOP (cyclophosphamide/doxorubicin/vincristine/prednisone) chemotherapy and R-CHOP (Rituximab + CHOP), either using alone or in combination with GM-CSF, have achieved great efficacy in DLBCL patients. However, the underlying mechanisms are still largely unknown.

METHODS

In the present study, the combination use of CHOP and R-CHOP with GM-CSF was used to evaluate their effects on the tumor immune microenvironment of DLBCL. CHOP and R-CHOP administration was found to inhibit the growth and metastasis of DLBCL, with a higher efficacy in R-CHOP-challenged DLBCL mice. The anti-tumor effect of CHOP and R-CHOP was further amplified by GM-CSF.

RESULTS

CHOP and R-CHOP therapeutics potentiated the anti-tumor properties of macrophages, as evidenced by the increased M1 macrophage and the decreased M2 macrophage accumulation in DLBCL-bearing mice. In a co-culture system, macrophages primed with CHOP and R-CHOP therapeutics inhibited multiple malignant behaviors of DLCBL cells. Mechanistically, CHOP/R-CHOP suppressed the activation of AKT signaling. These anti-tumor effects of CHOP/R-CHOP were all augmented by GM-CSF.

CONCLUSIONS

Our work provided new insights into the immune-regulatory roles of CHOP and R-CHOP in the treatment of DLBCL, as well as the synergistic effects of GM-CSF in CHOP and R-CHOP therapeutics. Although our results suggest the synergistic effect of GM-CSF on DLBCL already sensitive to CHOP and R-CHOP, however, future studies are warranted to explore the role of GM-CSF on R-CHOP-resistant DLBCL. Trial registration Not applicable.

The Role of Noncoding RNAs in B-Cell Lymphoma

In recent years, emerging evidence has suggested that noncoding RNAs (ncRNAs) participate in nearly every aspect of biological processes and play a crucial role in the genesis and progression of numerous tumors, including B-cell lymphoma. The exploration of ncRNA dysregulations and their functions in B-cell lymphoma provides new insights into lymphoma pathogenesis and is essential for indicating future clinical trials and optimizing the diagnostic and therapeutic strategies. In this review, we summarize the role of ncRNAs in B-cell lymphoma and discuss their potential in clinical applications.

Lymphotropic Viruses EBV, KSHV and HTLV in Latin America: Epidemiology and Associated Malignancies. A Literature-Based Study by the RIAL-CYTED

The Epstein-Barr virus (EBV), Kaposi sarcoma herpesvirus (KSHV) and human T-lymphotropic virus (HTLV-1) are lymphomagenic viruses with region-specific induced morbidity. The RIAL-CYTED aims to increase the knowledge of lymphoma in Latin America (LA), and, as such, we systematically analyzed the literature to better understand our risk for virus-induced lymphoma. We observed that high endemicity regions for certain lymphomas, e.g., Mexico and Peru, have a high incidence of EBV-positive lymphomas of T/NK cell origin. Peru also carries the highest frequency of EBV-positive classical Hodgkin lymphoma (HL) and EBV-positive diffuse large B cell lymphoma, not otherwise specified (NOS), than any other LA country. Adult T cell lymphoma is endemic to the North of Brazil and Chile. While only few cases of KSHV-positive lymphomas were found, in spite of the close correlation of Kaposi sarcoma and the prevalence of pathogenic types of KSHV. Both EBV-associated HL and Burkitt lymphoma mainly affect young children, unlike in developed countries, in which adolescents and young adults are the most affected, correlating with an early EBV seroconversion for LA population despite of lack of infectious mononucleosis symptoms. High endemicity of KSHV and HTLV infection was observed among Amerindian populations, with differences between Amazonian and Andean populations.

Targeting hydrogen sulphide signaling in breast cancer

Introduction

Hydrogen sulphide (H₂S) has been established as a key member of the gasotransmitters family that recently showed a pivotal role in various pathological conditions including cancer.

Objectives

This study investigated the role of H₂S in breast cancer (BC) pathogenesis, on BC immune recognition capacity and the consequence of targeting H₂S using non-coding RNAs.

Methods

Eighty BC patients have been recruited for the study. BC cell lines were cultured and transfected using validated oligonucleotide delivery system. Gene and protein expression analysis was performed using qRT-PCR, western blot and flow-cytometry. In-vitro analysis for BC hallmarks was performed using MTT, BrdU, Modified Boyden chamber, migration and colony forming assays. H₂S and nitric oxide (NO) levels were measured spectrophotometrically. Primary natural killer cells (NK cells) and T cell isolation and chimeric antigen receptor transduction (CAR T cells) were performed using appropriate kits. NK and T cells cytotoxicity was measured. Finally, computational target prediction analysis and binding confirmation analyses were performed using different software and dual luciferase assay kit, respectively.

Results

The H₂S synthesizing enzymes, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), exhibited elevated levels in the clinical samples that correlated with tumor proliferation index. Knock-down of CBS and CSE in the HER2+ BC and triple negative BC (TNBC) cells resulted in significant attenuation of BC malignancy. In addition to increased susceptibility of HER2+ BC and TNBC to the cytotoxic activity of HER2 targeting CAR T cells and NK cells, respectively. Transcriptomic and phosphoprotein analysis revealed that H₂S signaling is mediated through Akt in MCF7, STAT3 in MDA-MB-231 and miR-155/ NOS2/NO signaling in both cell lines. Lastly, miR-4317 was found to function as an upstream regulator of CBS and CSE synergistically abrogates the malignancy of BC cells.

Conclusion

These findings demonstrate the potential role of H₂S signaling in BC pathogenesis and the potential of its targeting for disease mitigation.

Clinical, histopathologic, and immunoarchitectural features of dermatopathic lymphadenopathy: an update

Dermatopathic lymphadenopathy is a distinctive form of paracortical lymph node hyperplasia that usually occurs in the setting of chronic dermatologic disorders. The aim of this study is to update our understanding of the clinicopathologic and immunophenotypic features of dermatopathic lymphadenopathy. The study cohort was 50 lymph node samples from 42 patients diagnosed with dermatopathic lymphadenopathy. The patients included 29 women and 13 men with a median age of 49 years (range, 12-79). Twenty-two (52%) patients had a dermatologic disorder, including mycosis fungoides (n = 6), chronic inflammatory dermatoses (n = 13), melanoma (n = 1), squamous cell carcinoma (n = 1), and Kaposi sarcoma in the context of human immunodeficiency virus infection (n = 1). Twenty (48%) patients did not have dermatologic manifestations. Lymph node biopsy specimens were axillary (n = 22), inguinal (n = 21), cervical (n = 4), and intramammary (n = 3). All lymph nodes showed paracortical areas expanded by lymphocytes; dendritic cells, including interdigitating dendritic cells and Langerhans cells; and macrophages. Melanophages were detected in 48 (98%) lymph nodes. Immunohistochemical analysis provided results that are somewhat different from those previously reported in the literature. In the paracortical areas of lymph node, S100 protein was expressed in virtually all dendritic cells, and CD1a was expressed in a significantly greater percentage of cells than langerin (80 vs. 35%, p < 0.0001). These results suggest that the paracortical regions of dermatopathic lymphadenopathy harbor at least three immunophenotypic subsets of dendritic cells: Langerhans cells (S100⁺, CD1a^+(high), langerin⁺), interdigitating dendritic cells (S100⁺, CD1a^+(low), langerin^-), and a third (S100⁺, CD1a^-, langerin^-) minor population of dendritic cells. Furthermore, in more than 60% of dermatopathic lymph nodes, langerin highlighted trabecular and medullary sinuses and cords, showing a linear and reticular staining pattern, which could be a pitfall in the differential diagnosis with Langerhans cell histiocytosis involving lymph nodes.

Transcriptional, Epigenetic and Metabolic Programming of Tumor-Associated Macrophages

Macrophages are key innate immune cells in the tumor microenvironment (TME) that regulate primary tumor growth, vascularization, metastatic spread and tumor response to various types of therapies. The present review highlights the mechanisms of macrophage programming in tumor microenvironments that act on the transcriptional, epigenetic and metabolic levels. We summarize the latest knowledge on the types of transcriptional factors and epigenetic enzymes that control the direction of macrophage functional polarization and their pro- and anti-tumor activities. We also focus on the major types of metabolic programs of macrophages (glycolysis and fatty acid oxidation), and their interaction with cancer cells and complex TME. We have discussed how the regulation of macrophage polarization on the transcriptional, epigenetic and metabolic levels can be used for the efficient therapeutic manipulation of macrophage functions in cancer.

Role of MicroRNAs in Host Defense against Infectious Bursal Disease Virus (IBDV) Infection: A Hidden Front Line

Infectious bursal disease (IBD) is an acute, highly contagious and immunosuppressive avian disease caused by infectious bursal disease virus (IBDV). In recent years, remarkable progress has been made in the understanding of the pathogenesis of IBDV infection and the host response, including apoptosis, autophagy and the inhibition of innate immunity. Not only a number of host proteins interacting with or targeted by viral proteins participate in these processes, but microRNAs (miRNAs) are also involved in the host response to IBDV infection. If an IBDV–host interaction at the protein level is taken imaginatively as the front line of the battle between invaders (pathogens) and defenders (host cells), their fight at the RNA level resembles the hidden front line. miRNAs are a class of non-coding single-stranded endogenous RNA molecules with a length of approximately 22 nucleotides (nt) that play important roles in regulating gene expression at the post-transcriptional level. Insights into the roles of viral proteins and miRNAs in host response will add to the understanding of the pathogenesis of IBDV infection. The interaction of viral proteins with cellular targets during IBDV infection were previously well-reviewed. This review focuses mainly on the current knowledge of the host response to IBDV infection at the RNA level, in particular, of the nine well-characterized miRNAs that affect cell apoptosis, the innate immune response and viral replication.