Constitutively activated STAT3 promotes cell proliferation and survival in the activated B-cell subtype of diffuse large B-cell lymphomas

Disruption of KLHL6 Fuels Oncogenic Antigen Receptor Signaling in B-Cell Lymphoma

Pathomechanisms that activate oncogenic B-cell receptor (BCR) signaling in diffuse large B-cell lymphoma (DLBCL) are largely unknown. Kelch-like family member 6 (KLHL6) encoding a substrate-adapter for Cullin-3-RING E3 ubiquitin ligase with poorly established targets is recurrently mutated in DLBCL. By applying high-throughput protein interactome screens and functional characterization, we discovered that KLHL6 regulates BCR by targeting its signaling subunits CD79A and CD79B. Loss of physiologic KLHL6 expression pattern was frequent among the MCD/C5-like activated B-cell DLBCLs and was associated with higher CD79B levels and dismal outcome. Mutations in the bric-a-brac tramtrack broad domain of KLHL6 disrupted its localization and heterodimerization and increased surface BCR levels and signaling, whereas Kelch domain mutants had the opposite effect. Malfunctions of KLHL6 mutants extended beyond proximal BCR signaling with distinct phenotypes from KLHL6 silencing. Collectively, our findings uncover how recurrent mutations in KLHL6 alter BCR signaling and induce actionable phenotypic characteristics in DLBCL. Significance: Oncogenic BCR signaling sustains DLBCL cells. We discovered that Cullin-3-RING E3 ubiquitin ligase substrate-adapter KLHL6 targets BCR heterodimer (CD79A/CD79B) for ubiquitin-mediated degradation. Recurrent somatic mutations in the KLHL6 gene cause corrupt BCR signaling by disrupting surface BCR homeostasis. Loss of KLHL6 expression and mutant-induced phenotypes associate with targetable disease characteristics in B-cell lymphoma. See related commentary by Leveille et al. See related commentary by Corcoran et al.

Advances in biology, diagnosis and treatment of DLBCL

Diffuse large B-cell lymphoma (DLBCL), with approximately 150,000 new cases worldwide each year, represent nearly 30% of all cases of non-Hodgkin lymphoma (NHL) and are phenotypically and genetically heterogeneous. A gene-expression profile (GEP) has identified at least three major subtypes of DLBCL, each of which has distinct clinical, biological, and genetic features: activated B-cell (ABC)-like DLBCL, germinal-center B-cell (GCB)-like DLBCL, and unclassified. Different origins are associated with different responses to chemotherapy and targeted agents. Despite DLBCL being a highly heterogeneous disease, more than 60% of patients with DLBCL can be cured after using rituximab combined with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) to inhibit the growth of cancer cells while targeting the CD20 receptor. In recent decades, the improvement of diagnostic levels has led to a refinement classification of DLBCL and the development of new therapeutic approaches. The objective of this review was to summarize the latest studies examining genetic lesions and therapies for DLBCL.

TCP1 expression alters the ferroptosis sensitivity of diffuse large B-cell lymphoma subtypes by stabilising ACSL4 and influences patient prognosis

Diffuse large B-cell lymphoma (DLBCL), an invasive lymphoma with substantial heterogeneity, can be mainly categorised into germinal centre B-cell-like (GCB) and non-GCB subtypes. DLBCL cells are highly susceptible to ferroptosis, which offers an effective avenue for treating recurrent and refractory DLBCL. Moreover, various heat shock proteins are involved in regulating the sensitivity of tumour cells to ferroptosis. Among these proteins, tailless complex polypeptide 1 (TCP1), a subunit of chaperonin-containing T-complex protein-1 (CCT), plays a role in tumour proliferation and survival. Therefore, we explored the role of TCP1 in different DLBCL subtypes, the sensitivity of GCB and non-GCB subtypes to the ferroptosis inducer RAS-selective lethal small molecule 3 (RSL3), and the underlying molecular mechanism. In GCB cells, TCP1 promoted RSL3-induced ferroptosis. Notably, TCP1 could bind with acyl-CoA synthetase long-chain family member 4 (ACSL4), a key enzyme regulating lipid composition and facilitating ferroptosis, to reduce its ubiquitination and degradation. This interaction activated the ACSL4/LPCAT3 signalling pathway and promoted ferroptosis in the GCB subtype. However, in the non-GCB subtype, TCP1 did not act as a positive regulator but served as a predictor of an unfavourable prognosis in patients with non-GCB. In conclusion, our results suggest that in DLBCL, high TCP1 expression enhances the sensitivity of GCB tumour cells to ferroptosis and serves as a marker of poor prognosis in patients with non-GCB DLBCL.

Epidermal loss of Bcl6 exacerbates MC903-induced atopic dermatitis-like skin inflammation

Atopic dermatitis (AD) is a chronic inflammatory skin disease where Th2-type immune responses are dominant. In the lesional skin of AD, keratinocytes show differentiation defects and secrete proinflammatory cytokines and chemokines, amplifying Th2-type responses in AD. We previously reported that inducible loss of B-cell lymphoma 6 (Bcl6), a transcription repressor and a master transcriptional regulator of follicular helper T cells and germinal center B cells, in the whole body results in upregulation of Th2-related cytokines in mouse skin. However, the role of Bcl6 in keratinocytes remains to be clarified. Here, we observed that BCL6 positively regulates the expression of keratinocyte differentiation markers and plasma membrane localization of adherence junctional proteins in keratinocyte cell culture. Although keratinocyte-specific loss of Bcl6 alone did not induce AD-like skin inflammation, it aggravates MC903-induced AD-like skin inflammation in mice. In addition, Bcl6 expression is decreased in the epidermis of lesional skin from MC903-induced AD-like skin inflammation in mice. These results strongly suggest that Bcl6 downregulation in keratinocytes contributes to the development and aggravation of AD-like skin inflammation in mice.

CD62L expression marks a functionally distinct subset of memory B cells

The memory B cell response consists of phenotypically distinct subsets that differ in their ability to respond upon antigen re-encounter. However, the pathways regulating the development and function of memory B cell subsets are poorly understood. Here, we show that CD62L and CD44 are progressively expressed on mouse memory B cells and identify transcriptionally and functionally distinct memory B cell subsets. Bcl6 is important in regulating memory B cell subset differentiation with overexpression of Bcl6 resulting in impaired CD62L+ memory B cell development. Bcl6 regulates memory B cell subset development through control of a network of genes, including Bcl2 and Zeb2. Overexpression of Zeb2 impairs the development of CD62L+ memory B cells. Importantly, CD62L is also differentially expressed on human memory B cells following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and identifies phenotypically distinct populations. Together, these data indicate that CD62L expression marks functionally distinct memory B cell subsets.

Specific Targeting of STAT3 in B Cells Suppresses Progression of B Cell Lymphoma

The signal transducer and activator of transcription 3 (STAT3), which regulates multiple oncogenic processes, has been found to be constitutively activated in lymphoma, suggesting its potential as a therapeutic target. Here, we constructed an anti-CD19-N-(4-carboxycyclohexylmethyl) maleimide N-hydroxysuccinimide ester (SMCC)-protamine (CSP)-STAT3 small interfering RNA (siRNA) conjugate and demonstrated that the CSP-STAT3 siRNA conjugate could specifically bind to normal B cells and A20 lymphoma cells in vitro. It decreased the STAT3 expression in B cell lymphoma cell lines (A20, SU-DHL-2 and OCI-Ly3), resulting in reduced proliferation of lymphoma cells featured with lower S-phase and higher apoptosis. Using an A20 transplantable lymphoma model, we found that the CSP-STAT3 siRNA conjugate significantly inhibited tumor growth and weight. Ki-67, p-STAT3, STAT3, and serum IL-6 levels were all significantly reduced in A20-bearing mice treated with CSP-STAT3 siRNA. These findings indicate that specifically targeting STAT3 siRNA to B cell lymphoma cell lines can significantly decrease STAT3 activity and inhibit tumor progression in vitro and in vivo, suggesting its potential utilization for cancer treatment.

The role of chidamide in the treatment of B-cell non-Hodgkin lymphoma: An updated systematic review

B-cell non-Hodgkin lymphoma (B-NHL) is a lymphoid malignancy derived from B-cells that remains difficult to treat. Moreover, relapses and refractory cases are common. Abnormalities in epigenetic mechanisms, such as imbalanced histone acetylation affecting certain genes, contribute to relapses and refractory cases. Chidamide (tucidinostat) is a novel histone deacetylase inhibitor that can reverse this epigenetic imbalance and has been approved for the treatment of T-cell malignancies. However, the use of chidamide for B-NHL remains limited, and the lack of relevant literature exacerbates this limitation. We conducted this review to summarize the anticancer activity of chidamide against B-NHL and its clinical applications to overcome drug resistance. This systematic review was conducted according to the PRISMA 2020 guidelines, using some keyword combinations from MEDLINE and EBSCO. The inclusion and exclusion criteria were also defined. Of the 131 records retrieved from databases, 16 were included in the review. Nine articles revealed that chidamide limited tumor progression by modifying the tumor microenvironment, stopping the cell cycle, inducing apoptosis and autophagy, and enhancing complement-dependent and antibody-dependent cell-mediated cytotoxicities.According to seven other studies, administering chidamide in combination with another existing therapeutic regimen may benefit not only patients with relapsed/refractory B-NHL, but also those with newly diagnosed B-NHL. Chidamide plays many important roles in limiting B-NHL progression through epigenetic modifications. Thus, combining chidamide with other anticancer drugs may be more beneficial for patients with newly diagnosed and relapsed/refractory B-NHL.

Phase I Study of Acalabrutinib Plus Danvatirsen (AZD9150) in Relapsed/Refractory Diffuse Large B-Cell Lymphoma Including Circulating Tumor DNA Biomarker Assessment

PURPOSE

Novel targeted and immunotherapies have improved outcomes in relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), but toxicities limit widespread use. The selective Bruton tyrosine kinase (BTK) inhibitor acalabrutinib has activity in patients with R/R DLBCL but durable responses are uncommon. STAT3 inhibition has demonstrated clinical activity in DLBCL.

PATIENTS AND METHODS

Final results of the phase I study of acalabrutinib plus STAT3 inhibitor (danvatirsen; AZD9150) in patients with R/R DLBCL are reported. Danvatirsen 200 mg intravenous infusion [Days 1, 3, 5 (Cycle 1); weekly infusions starting Day 8, Cycle 1] was administered in combination with oral acalabrutinib 100 mg twice daily until progressive disease (PD) or unacceptable toxicity. Primary endpoints were safety and tolerability. Secondary endpoints included efficacy, pharmacokinetics, and immunogenicity.

RESULTS

Seventeen patients received combination treatment. One dose-limiting toxicity (Grade 3 liver transaminase) occurred in 1 patient. The most common reason for treatment discontinuation was PD (65%). In evaluable patients (n = 17), objective response rate was 24%; median duration of response was 1.9 months. All responders with available DLBCL cell-of-origin data were either activated B-cell or nongerminal center B-cell like subtype. Genetic subtype did not correlate with response. Baseline and longitudinal plasma cell-free DNA (cfDNA) concentrations were mostly higher in nonresponding patients. cfDNA changes were generally concordant with imaging. Pretreatment circulating B-cell levels were higher in responders versus nonresponders.

CONCLUSIONS

Targeting both STAT3 and BTK in combination is safe and tolerable but efficacy is limited in R/R DLBCL. Results support evaluation of circulating tumor DNA as a biomarker for clinical response.

Maternal infection causes dysfunctional BCR signaling in male offspring due to aberrant Xist expression

Infections during pregnancy with pathogens such as helminths correlate with altered immune responses to common childhood immunizations. However, the molecular mechanisms that underlie this remain unknown. Using our murine model of maternal schistosomiasis, when immunized, males from infected mothers had a lower frequency of antigen-specific germinal center B cells and downregulation of transcripts downstream of BCR signaling compared to males from uninfected mothers. This is driven by a reduction in developing B cell populations within the bone marrow of pups from infected mothers. Males from infected mothers were impacted to a greater extent than their female littermate counterparts. We found this defect to be caused by aberrant expression of the long non-coding RNA Xist in males leading to dysregulated Igα expression on developing B cells. This, for the first time, links dysfunctional BCR signaling with Xist expression, while also proposing a detrimental function for Xist expression in males.

Expression of TCF3 target genes defines a subclass of diffuse large B-cell lymphoma characterized by up-regulation of MYC target genes and poor clinical outcome following R-CHOP therapy

TCF3 is a lymphopoietic transcription factor that acquires somatic driver mutations in diffuse large B-cell lymphoma (DLBCL). Hypothesizing that expression patterns of TCF3-regulated genes can inform clinical management, we found that unsupervised clustering analysis with 15 TCF3-regulated genes and eight additional ones resolved local DLBCL cases into two main clusters, denoted Groups A and B, of which Group A manifested inferior overall survival (OS, p = 0.0005). We trained a machine learning model to classify samples into the Groups based on expression of the 23 transcripts in an independent validation cohort of 569 R-CHOP-treated DLBCL cases. Group A overlapped with the ABC cell-of-origin subgroup but its prognostic power was superior. GSEA analysis demonstrated asymmetric expression of 30 gene sets between the Groups, pointing to biological differences. We present, validate and make available a novel method to assign DLBCL cases into biologically-distinct groups with divergent OS following R-CHOP therapy.

Obesity and Risk for Lymphoma: Possible Role of Leptin

Obesity, which is considered a pandemic due to its high prevalence, is a risk factor for many types of cancers, including lymphoma, through a variety of mechanisms by promoting an inflammatory state. Specifically, over the last few decades, obesity has been suggested not only to increase the risk of lymphoma but also to be associated with poor clinical outcomes and worse responses to different treatments for those diseases. Within the extensive range of proinflammatory mediators that adipose tissue releases, leptin has been demonstrated to be a key adipokine due to its pleotropic effects in many physiological systems and diseases. In this sense, different studies have analyzed leptin levels and leptin/leptin receptor expressions as a probable bridge between obesity and lymphomas. Since both obesity and lymphomas are prevalent pathophysiological conditions worldwide and their incidences have increased over the last few years, here we review the possible role of leptin as a promising proinflammatory mediator promoting lymphomas.

Establishment and characterization of a new activated B-cell-like DLBCL cell line, TMD12

We report the establishment of a novel activated B-cell-like (ABC) diffuse large B-cell lymphoma (DLBCL) cell line, designated as TMD12, from a patient with highly refractory DLBCL. ABC-DLBCL is a subtype with a relatively unfavorable prognosis that was originally categorized using gene expression profiling according to its cell of origin. TMD12 cells were isolated from the pleural effusion of the patient at relapse and passaged continuously in vitro for >4 years. The cells displayed cluster of differentiation (CD)19, CD20, CD22, CD38, human leukocyte antigen-DR isotype, and κ positivity and CD5, CD10, CD23, and λ negativity, as detected using flow cytometric analysis. The chromosomal karyotypic analysis, including the spectral karyotyping method, confirmed t(1;19)(q21:q13.1), del(6q23), gain of chromosome 18, and other abnormalities. Mutation analyses, including whole-exome sequencing, revealed that TMD12 cells harbored mutations in MYD88 and CD79B, indicating an ABC subtype. TMD12 cells exhibited chronic active B-cell receptor signaling and constitutive activation of the nuclear factor κB pathway, which is typically associated with sensitivity to a specific Bruton tyrosine kinase inhibitor, ibrutinib. Intriguingly, TMD12 cells displayed moderate resistance to ibrutinib and lacked activation of Janus kinase/signal transducers and activators of transcription 3 signaling, another hallmark of this DLBCL subtype. Treatment with an inhibitor against tumor progression locus 2 (TPL2), a multifunctional intracellular kinase that is activated particularly downstream of Toll-like receptors or MYD88 and IκB kinase α/β (IKKα/β), suppressed the proliferation of TMD12 cells, implying the possible involvement of the TPL2-p105 pathway in the tumorigenesis of ABC-DLBCL. Because only a limited number of ABC-DLBCL cell lines are currently available, TMD12 cells might provide a useful tool in the search for novel druggable targets for this intractable lymphoma.

Interfering B cell receptor signaling via SHP-1/p-Lyn axis shows therapeutic potential in diffuse large B-cell lymphoma

Background

Diffuse large B cell lymphoma (DLBCL) is an aggressive and molecularly heterogeneous non-Hodgkin’s lymphoma. The B cell receptor (BCR) signaling pathway in DLBCL emerges as a new drug target. Protein phosphatase SHP-1 negatively regulates several oncogenic tyrosine kinases and plays a tumor suppressive role.

Methods

The direct SHP-1 agonists were used to evaluate the potential therapeutic implication of SHP-1 in DLBCL. Immunohistochemical staining for SHP-1 was quantified by H-score. The SHP-1 phosphatase activity was determined using tyrosine phosphatase assay. In vitro studies, including MTT, western blot analysis and cell apoptosis, were utilized to examined biological functions of SHP-1.

Results

Oral administration of SHP-1 agonist showed the potent anti-tumor effects compared to a selective Bruton’s tyrosine kinase (BTK) inhibitor ibrutinib in mice bearing U2932 xenografts. SHP-1 agonist increased SHP-1 activity as well as downregulated p-Lyn in vivo. Here, we demonstrated that immunohistochemical staining for SHP-1 expression was positive in 76% of DLBCL samples. SHP-1 agonist exerted anti-proliferative and apoptotic effects compared with ibrutinib in DLBCL cells. Mechanistically, SHP-1 agonist decreased BCR signaling, especially p-Lyn, and led to apoptosis.

Conclusions

These data suggest that SHP-1 negatively regulates phosphorylation of Lyn, and targeting SHP-1/p-Lyn using SHP-1 agonist has therapeutic potential for treatment of DLBCL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00518-0.

Downregulation of STAT3 in Epstein-Barr Virus-Positive Hodgkin Lymphoma

STAT3 is a transcription factor which is activated via various signaling transduction pathways or Epstein-Barr virus (EBV) infection and plays an oncogenic role in lymphoid malignancies including Hodgkin lymphoma (HL). The tumor cells of HL are derived from germinal center B-cells and transformed by chromosomal rearrangements, aberrant signal transduction, deregulation of developmental transcription factors, and EBV activity. HL cell lines represent useful models to investigate molecular principles and deduced treatment options of this malignancy. Using cell line L-540, we have recently shown that constitutively activated STAT3 drives aberrant expression of hematopoietic NKL homeobox gene HLX. Here, we analyzed HL cell line AM-HLH which is EBV-positive but, nevertheless, HLX-negative. Consistently, AM-HLH expressed decreased levels of STAT3 proteins which were additionally inactivated and located in the cytoplasm. Combined genomic and expression profiling data revealed several amplified and overexpressed gene candidates involved in opposed regulation of STAT3 and EBV. Corresponding knockdown studies demonstrated that IRF4 and NFATC2 inhibited STAT3 expression. MIR155 (activated by STAT3) and SPIB (repressed by HLX) showed reduced and elevated expression levels in AM-HLH, respectively. However, treatment with IL6 or IL27 activated STAT3, elevated expression of HLX and MIR155, and inhibited IRF4. Taken together, this cell line deals with two conflicting oncogenic drivers, namely, JAK2-STAT3 signaling and EBV infection, but is sensitive to switch after cytokine stimulation. Thus, AM-HLH represents a unique cell line model to study the pathogenic roles of STAT3 and EBV and their therapeutic implications in HL.

Anticancer activity of IRAK-4 inhibitors against canine lymphoid malignancies

The interleukin-1 receptor-related kinase 4 (IRAK4), downstream of myd88, plays an essential role in hyperactive TLR signaling seen in some B-cell lymphomas. In particular, efficient IRAK4 inhibitors of activated B-cell subtype of human diffuse large B-Cell lymphoma (DLBCL) are being developed. However, the anticancer effect of IRAK-4 inhibitors in veterinary medicine has not been elucidated. It is therefore explored in this study involving the GL-1 and CL-1 canine lymphoma cell lines in vitro. MyD88 expression was analysed using polymerase chain reaction. GL-1 and CL-1 cells were subjected to concentration- and time-dependent treatment with an IRAK-4 inhibitor and assessed for viability, TLR signalling association, and apoptosis using a cell counting Kit-8 assay, Western blotting, and flow cytometry. The GL-1 and CL-1 cells exhibited enhanced MyD88 expression, however, canine peripheral blood mononuclear cells (cPBMCs) did not. The IRAK-4 inhibitor reduced cell viability in a dose- and time-dependent manner, significantly reduced the phosphorylation of molecules associated with TLR signalling at IC₅₀ such as IRAK1, IRAK4, NF-κB and STAT3, and induced apoptosis in GL-1 and CL-1 cells. The anticancer effect of the IRAK-4 inhibitor on canine lymphoma cells is mediated by apoptosis via downregulation of TLR signalling. This article is protected by copyright. All rights reserved.

Curcumin as a Potential Therapeutic Agent in Certain Cancer Types

Cancer is a devastating disease condition and is the second most common etiology of death globally. After decades of research in the field of hematological malignancies and cellular therapeutics, we are still looking for therapeutic agents with the most efficacies and least toxicities. Curcumin is one of the cancer therapeutic agents that is derived from the Curcuma longa (turmeric) plant, and still in vitro and in vivo research is going on to find its beneficial effects on various cancers. Due to its potency to affect multiple targets of different cellular pathways, it is considered a promising agent to tackle various cancers alone or in combination with the existing chemotherapies. This review covers basic properties, mechanism of action, potential targets (molecules and cell-signaling pathways) of curcumin, as well as its effect on various solid and hematological malignancies. 

The Effect of the Tumor Microenvironment on Lymphoid Neoplasms Derived from B Cells

Lymphomas are characteristic tumors surrounded by an inflammatory microenvironment. The cells of the microenvironment are essential for the growth and survival of neoplastic cells and are recruited through the effect of cytokines/chemokines. Lymphomas include heterogeneous groups of neoplasms infiltrating various lymphoid structures which may arise from B lymphocytes, T lymphocytes, and natural killer (NK) cells at various stages of their differentiation state. In this review article, we analyze the literature data concerning the involvement of the tumor microenvironment (TME) in the progression of lymphomas and the recent advances in the analysis of microenvironment components in the most common forms: some mature B cell lymphoma neoplasms and classic Hodgkin lymphomas. The complex crosstalk between the TME and tumor cells led to the discovery of many mechanisms usable as molecular-targeted therapy through the control of diverse elements of the TME, varying from inhibitors of angiogenic cytokines and their receptors to the regulation of cells' activities and the novel immune checkpoint inhibitors.

MYD88L265P and CD79B double mutations type (MCD type) of diffuse large B-cell lymphoma: mechanism, clinical characteristics, and targeted therapy

MYD88/CD79B-mutated (MCD) genotype is a genetic subgroup of diffuse large B-cell lymphoma (DLBCL) with the co-occurrence of MYD88^L265P and CD79B mutations. MCD genotype is characterized by poor prognosis and extranodal involvement especially in immune-privileged sites. MCD model is dominated by activated B-cell (ABC)-like subtype of DLBCLs. It is generally accepted that the pathogenesis of MCD DLBCL mainly includes chronic active B-cell receptor (BCR) signaling and oncogenic MYD88 mutations, which drives pathological nuclear factor kappa B (NF-κB) activation in MCD lymphoid malignancies. CD79B and MYD88^L265P mutations are frequently and contemporaneously founded in B-cell malignancies. The collaboration of the two mutations may explain the unique biology of MCD. Meanwhile, standard immunochemotherapy combine with different targeted therapies worth further study to improve the prognosis of MCD, according to genetic, phenotypic, and clinical features of MCD type. In this review, we systematically described mechanism, clinical characteristics, and targeted therapy of MCD DLBCL.

Tumor cell-derived IL-10 promotes cell-autonomous growth and immune escape in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is an aggressive malignancy arising from germinal center or post-germinal center B-cells that retain many of the properties of normal B-cells. Here we show that a subset of DLBCL express the cytokine IL-10 and its receptor. The genetic ablation of IL-10 receptor signaling abrogates the autocrine STAT3 phosphorylation triggered by tumor cell-intrinsic IL-10 expression and impairs growth of DLBCL cell lines in subcutaneous and orthotopic xenotransplantation models. Furthermore, we demonstrate using an immunocompetent Myc-driven model of DLBCL that neutralization of IL-10 signaling reduces tumor growth, which can be attributed to reduced Treg infiltration, stronger intratumoral effector T-cell responses, and restored tumor-specific MHCII expression. The effects of IL-10R neutralization were phenocopied by the genetic ablation of IL-10 signaling in the Treg compartment and could be reversed by MHCII blockade. The BTK inhibitor ibrutinib effectively blocked tumor cell-intrinsic IL-10 expression and tumor growth in this Myc-driven model. Tumors from patients with high IL-10RA expression are infiltrated by higher numbers of Tregs than IL-10RA^low patients. Finally, we show in 16 cases of DLBCL derived from transplant patients on immunosuppressive therapy that IL-10RA expression is less common in this cohort, and Treg infiltration is not observed.

Artesunate induces apoptosis, autophagy and ferroptosis in diffuse large B cell lymphoma cells by impairing STAT3 signaling

Artesunate (ART), a water-soluble derivative of artemisinin, has been reported to exert antineoplastic effects via diverse mechanisms in various types of cancer. Therefore, understanding the underlying mechanism of action of ART in distinct cancer types is indispensable to optimizing the therapeutic application of ART for different types of cancer. The present study aimed to investigate the cellular and molecular mechanisms responsible for the antineoplastic effects of ART in diffuse large B cell lymphoma (DLBCL) cells. Cell proliferation was measured using Cell Counting Kit-8 and colony formation assays. The levels of apoptosis and cell cycle distribution were investigated using flow cytometry. In addition, western blotting was used to analyze the expression levels of ART-induced apoptosis-, autophagy- and ferroptosis-related proteins. Monodansylcadaverine staining was performed to determine the levels of autophagy. Moreover, malondialdehyde and reactive oxygen species assays were used to determine the levels of ferroptosis. The results of the present study revealed that ART inhibited proliferation, and induced apoptosis, cell cycle arrest, autophagy and ferroptosis in DLBCL cells. Pharmacological inhibition of autophagy and ferroptosis alleviated the increased levels of apoptosis induced by ART. Notably, ART was found to exert its effects via inhibition of STAT3 activation. The genetic knockdown of STAT3 enhanced ART-induced autophagy and ferroptosis, and concomitantly upregulated the expression levels of apoptosis- and cell cycle-related proteins. In conclusion, the findings of the current study suggested that ART may induce apoptosis and cell cycle arrest to inhibit cell proliferation, and regulate autophagy and ferroptosis via impairing the STAT3 signaling pathway in DLBCL cells.

The PD-1/PD-L1 Checkpoint in Normal Germinal Centers and Diffuse Large B-Cell Lymphomas

Besides a recognized role of PD-1/PD-L1 checkpoint in anti-tumour immune evasion, there is accumulating evidence that PD-1/PD-L1 interactions between B and T cells also play an important role in normal germinal center (GC) reactions. Even when smaller in number, T follicular helper cells (TFH) and regulatory T (TFR) or B (Breg) cells are involved in positive selection of GC B cells and may result critical in the lymphoma microenvironment. Here, we discuss a role of PD-1/PD-L1 during tumour evolution in diffuse large B cell lymphoma (DLBCL), a paradigm of GC-derived lymphomagenesis. We depict a progression model, in two phases, where malignant B cells take advantage of positive selection signals derived from correct antigen-presentation and PD-1/PD-L1 inter-cellular crosstalks to survive and initiate tumour expansion. Later, a constant pressure for the accumulation of genetic/epigenetic alterations facilitates that DLBCL cells exhibit higher PD-L1 levels and capacity to secrete IL-10, resembling Breg-like features. As a result, a complex immunosuppressive microenvironment is established where DLBCL cells sustain proliferation and survival by impairing regulatory control of TFR cells and limiting IL-21-mediated anti-tumour functions of TFH cells and maximize the use of PD-1/PD-L1 signaling to escape from CD8+ cytotoxic activity. Integration of these molecular and cellular addictions into a framework may contribute to the better understanding of the lymphoma microenvironment and contribute to the rationale for novel PD-1/PD-L1-based combinational immunotherapies in DLBCL.

Primary central nervous system lymphoma: clinicopathological and genomic insights for therapeutic development

Primary central nervous system lymphoma (PCNSL) is a highly aggressive, extra-nodal non-Hodgkin lymphoma that is confined to the central nervous system (CNS) and the eyes. Most PCNSLs arise in immunocompetent older patients and less frequently in immunocompromised patients with Epstein-Barr virus infection. Although a patient's initial response to chemotherapy and radiation therapy is favorable, the clinical outcome of PCNSL remains poor compared to that of systemic lymphoma. Radiation-induced neurotoxicity is also a critical problem for patients with PCNSL. Therefore, a novel therapeutic strategy is required to overcome these challenges. Recent studies have largely uncovered the genomic landscape and associated histopathological features of PCNSL. Based on this background, novel therapeutic agents, such as Bruton's tyrosine kinase inhibitors and immune checkpoint inhibitors, have been introduced for patients with PCNSL. Here, we provide an overview of the updated histopathological and genomic characterization of PCNSL and summarize the current therapeutic strategies. We also review current preclinical PCNSL models for translational research.

The Positivity of Phosphorylated STAT3 Is a Novel Marker for Favorable Prognosis in Germinal Center B-Cell Type of Diffuse Large B-Cell Lymphoma

On the basis of immunohistochemistry, diffuse large B-cell lymphoma (DLBCL) is categorized as a germinal center B-cell (GCB) or non-GCB subtype. Recent integrated genomic analyses have highlighted the importance of the JAK-STAT3 pathway in the molecular pathogenesis of DLBCL. However, its relevance to clinical outcomes remains controversial. Therefore, we evaluated the extent of the nuclear expression of phosphorylated STAT3 (pSTAT3), a surrogate marker of signal transducer and activator of transcription 3 (STAT3) activation, by immunohistochemistry. We also analyzed the potential relationship between pSTAT3 positivity (defined as ≥40% positive neoplastic cells) and clinicopathologic characteristics in 294 patients with DLBCL. pSTAT3 was detected in 122 patients (42%), with a higher rate in the non-GCB subtype than in the GCB subtype (57% vs. 28%, P<0.001). Factors potentially activating STAT3, MYD88L265P, and Epstein-Barr virus-encoded small RNA were identified in the pSTAT3-positive non-GCB subtype, whereas the pSTAT3-positive GCB subtype often showed STAT3 mutations and lacked EZH2 mutations and the rearrangements of BCL2 and MYC. Multivariate analyses revealed that the pSTAT3-positive GCB subtype showed a favorable prognosis (HR: 0.17; 95% confidence interval, 0.04-0.7; P=0.014). These findings suggest that pSTAT3 positivity may have a unique impact on the clinicopathologic characteristics of DLBCL, making it a promising novel marker for the favorable prognosis of patients with the GCB subtype.

Study of the antilymphoma activity of pracinostat reveals different sensitivities of DLBCL cells to HDAC inhibitors

Histone deacetylase inhibitors (HDACis) are antitumor agents with distinct efficacy in hematologic tumors. Pracinostat is a pan-HDACi with promising early clinical activity. However, similar to other HDACis, its activity as a single agent is limited. Diffuse large B-cell lymphoma (DLBCL) includes distinct molecular subsets or metabolically defined subtypes that rely in different ways on the B-cell receptor signaling pathway, oxidative phosphorylation, and glycolysis for their survival. The antitumor activity of pracinostat has not been determined in lymphomas. We performed preclinical in vitro activity screening of 60 lymphoma cell lines that included 25 DLBCLs. DLBCL cells belonging to distinct metabolic subtypes were treated with HDACis for 6 hours or 14 days followed by transcriptional profiling. DLBCL xenograft models enabled assessment of the in vivo antilymphoma activity of pracinostat. Combination treatments with pracinostat plus 10 other antilymphoma agents were performed. Western blot was used to assess acetylation levels of histone and nonhistone proteins after HDACi treatment. Robust antiproliferative activity was observed across all lymphoma histotypes represented. Focusing on DLBCL, we identified a low-sensitivity subset that almost exclusively consists of the oxidative phosphorylation (OxPhos)-DLBCL metabolic subtype. OxPhos-DLBCL cells also showed poorer sensitivity to other HDACis, including vorinostat. Transcriptomic analysis revealed fewer modulated transcripts but an enrichment of antioxidant pathway genes after HDACi treatment of OxPhos-DLBCLs compared with high-sensitivity B-cell receptor (BCR)-DLBCLs. Pharmacologic inhibition of antioxidant production rescued sensitivity of OxPhos-DLBCLs to pracinostat whereas BCR-DLBCLs were unaffected. Our study provides novel insights into the antilymphoma activity of pracinostat and identifies a differential response of DLBCL metabolic subtypes to HDACis.

Diffuse Large B-Cell Lymphoma: Recognition of Markers for Targeted Therapy

Diffuse large B-cell lymphomas (DLBCL)s, the most common type of Non-Hodgkin’s Lymphoma, constitute a heterogeneous group of disorders including different disease sites, strikingly diverse molecular features and a profound variability in the clinical behavior. Molecular studies and clinical trials have partially revealed the underlying causes for this variability and have made possible the recognition of some molecular variants susceptible of specific therapeutic approaches. The main histogenetic groups include the germinal center, activated B cells, thymic B cells and terminally differentiated B cells, a basic scheme where the large majority of DLBCL cases can be ascribed. The nodal/extranodal origin, specific mutational changes and microenvironment peculiarities provide additional layers of complexity. Here, we summarize the status of the knowledge and make some specific proposals for addressing the future development of targeted therapy for DLBC cases.

EGR1 Addiction in Diffuse Large B-cell Lymphoma

Early growth response gene (EGR1) is a transcription factor known to be a downstream effector of B-cell receptor signaling and Janus kinase 1 (JAK1) signaling in diffuse large B-cell lymphoma (DLBCL). While EGR1 is characterized as a tumor suppressor in leukemia and multiple myeloma, the role of EGR1 in lymphoma is unknown. Here we demonstrate that EGR1 is a potential oncogene that promotes cell proliferation in DLBCL. IHC analysis revealed that EGR1 expression is elevated in DLBCL compared with normal lymphoid tissues and the level of EGR1 expression is higher in activated B cell-like subtype (ABC) than germinal center B cell-like subtype (GCB). EGR1 expression is required for the survival and proliferation of DLBCL cells. Genomic analyses demonstrated that EGR1 upregulates expression of MYC and E2F pathway genes through the CBP/p300/H3K27ac/BRD4 axis while repressing expression of the type I IFN pathway genes by interaction with the corepressor NAB2. Genetic and pharmacologic inhibition of EGR1 synergizes with the BRD4 inhibitor JQ1 or the type I IFN inducer lenalidomide in growth inhibition of ABC DLBCL both in cell cultures and xenograft mouse models. Therefore, targeting oncogenic EGR1 signaling represents a potential new targeted therapeutic strategy in DLBCL, especially for the more aggressive ABC DLBCL. IMPLICATIONS: The study characterizes EGR1 as a potential oncogene that promotes cell proliferation and defines EGR1 as a new molecular target in DLBCL, the most common non-Hodgkin lymphoma.

MAP-kinase and JAK-STAT pathways dysregulation in plasmablastic lymphoma

Plasmablastic lymphoma (PBL) is an aggressive B-cell lymphoma with an immunoblastic/large cell morphology and plasmacytic differentiation. The differential diagnosis with Burkitt lymphoma (BL), plasma cell myeloma (PCM) and some variants of diffuse large B-cell lymphoma (DLBCL) may be challenging due to the overlapping morphological, genetic and immunophenotypic features. Furthermore, the genomic landscape in PBL is not well known. To characterize the genetic and molecular heterogeneity of these tumors, we investigated thirty-four PBL using an integrated approach, including fluorescence in situ hybridization, targeted sequencing of 94 B-cell lymphoma related genes, and copy-number arrays. PBL were characterized by high genetic complexity including MYC translocations (87%), gains of 1q21.1-q44, trisomy 7, 8q23.2-q24.21, 11p13-p11.2, 11q14.2-q25, 12p and 19p13.3-p13.13, losses of 1p33, 1p31.1-p22.3, 13q and 17p13.3-p11.2, and recurrent mutations of STAT3 (37%), NRAS and TP53 (33%), MYC and EP300 (19%) and CARD11, SOCS1 and TET2 (11%). Pathway enrichment analysis suggested a cooperative action between MYC alterations and MAPK (49%) and JAK-STAT (40%) signaling pathways. Of note, EBVnegative PBL cases had higher mutational and copy-number load and more frequent TP53, CARD11 and MYC mutations, whereas EBV-positive PBL tended to have more mutations affecting the JAK-STAT pathway. In conclusion, these findings further unravel the distinctive molecular heterogeneity of PBL identifying novel molecular targets and the different genetic profile of these tumors related to EBV infection.

Genetic Events Inhibiting Apoptosis in Diffuse Large B Cell Lymphoma

Simple Summary

Diffuse large B cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma (NHL). Despite the genetic heterogeneity of the disease, most patients are initially treated with a combination of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), but relapse occurs in ~50% of patients. One of the hallmarks of DLBCL is the occurrence of genetic events that inhibit apoptosis, which contributes to disease development and resistance to therapy. These events can affect the intrinsic or extrinsic apoptotic pathways, or their modulators. Understanding the factors that contribute to inhibition of apoptosis in DLBCL is crucial in order to be able to develop targeted therapies and improve outcomes, particularly in relapsed and refractory DLBCL (rrDLBCL). This review provides a description of the genetic events inhibiting apoptosis in DLBCL, their contribution to lymphomagenesis and chemoresistance, and their implication for the future of DLBCL therapy.

Abstract

Diffuse large B cell lymphoma (DLBCL) is curable with chemoimmunotherapy in ~65% of patients. One of the hallmarks of the pathogenesis and resistance to therapy in DLBCL is inhibition of apoptosis, which allows malignant cells to survive and acquire further alterations. Inhibition of apoptosis can be the result of genetic events inhibiting the intrinsic or extrinsic apoptotic pathways, as well as their modulators, such as the inhibitor of apoptosis proteins, P53, and components of the NF-kB pathway. Mechanisms of dysregulation include upregulation of anti-apoptotic proteins and downregulation of pro-apoptotic proteins via point mutations, amplifications, deletions, translocations, and influences of other proteins. Understanding the factors contributing to resistance to apoptosis in DLBCL is crucial in order to be able to develop targeted therapies that could improve outcomes by restoring apoptosis in malignant cells. This review describes the genetic events inhibiting apoptosis in DLBCL, provides a perspective of their interactions in lymphomagenesis, and discusses their implication for the future of DLBCL therapy.

Chidamide induces apoptosis in DLBCL cells by suppressing the HDACs/STAT3/Bcl‑2 pathway

Diffuse large B‑cell lymphoma (DLBCL) is a highly heterogeneous malignant tumor type, and epigenetic modifications such as acetylation or deacetylation serve vital roles in its development. Chidamide, a novel histone deacetylase inhibitor, exerts an anticancer effect against various types of cancer. The present study aimed to evaluate the cellular effect of chidamide on a number of DLBCL cell lines and to investigate its underlying mechanism. The results demonstrated that chidamide induced the death of these cells in a concentration‑(0‑30 µmol/l) and time‑dependent (24‑72 h) manner, as determined using the Cell Counting Kit‑8 cell viability assay. Moreover, chidamide promoted cellular apoptosis, which was identified via flow cytometry and western blot analysis, with an increase in cleaved caspase‑3 expression and a decrease in Bcl‑2 expression. Chidamide treatment also decreased the expression level of STAT3 and its phosphorylation, which was accompanied by the downregulation of a class‑I histone deacetylase (HDAC) inhibitor, chidamide. Collectively, these data suggested that chidamide can be a potent therapeutic agent to treat DLBCL by inducing the apoptotic death of DLBCL cells by inhibiting the HDACs/STAT3/Bcl‑2 pathway.

Pseurotin D Inhibits the Activation of Human Lymphocytes

Background: Pseurotins, a family of secondary metabolites of different fungi characterized by an unusual spirocyclic furanone-lactam core, are suggested to have different biological activities including the modulation of immune response. Purpose: Complex characterization of the effects of pseurotin D on human lymphocyte activation in order to understand the potential of pseurotin to modulate immune response in humans. Methods: CD4+ and CD8+ T cells and CD19+ B cells isolated from human blood were activated by various activators simultaneously with pseurotin D treatment. The effects of pseurotin were tested on the basis of changes in cell viability, apoptosis, activation of signal transducers and activators of transcription (STAT) signaling pathways, production of tumor necrosis factor (TNF)-α by T cells, expression of activation markers CD69 and CD25 on T cells and Human Leukocyte Antigen–DR isotype (HLA-DR) on B cells, and the differentiation markers CD20, CD27, CD38, and immunoglobulin (Ig) D on B cells. Results: Pseurotin D significantly inhibited the activation of both CD4+ and CD8+ human T cells complemented by the inhibition of TNF-α production without significant acute toxic effects. The Pseurotin D-mediated inhibition of T-cell activation was accompanied by the induction of the apoptosis of T cells. This corresponded with the inhibited phosphorylation of STAT3 and STAT5. In human B cells, pseurotin D did not significantly inhibit their activation; however, it affected their differentiation. Conclusions: Our results advance the current mechanistic understanding of the pseurotin-induced inhibition of lymphocytes and suggest pseurotins as new attractive chemotypes for future research in the context of immune-modulatory drugs.

Genome-wide Screens Identify Lineage- and Tumor-Specific Genes Modulating MHC-I- and MHC-II-Restricted Immunosurveillance of Human Lymphomas

Tumors frequently subvert major histocompatibility complex class I (MHC-I) peptide presentation to evade CD8+ T cell immunosurveillance, though how this is accomplished is not always well defined. To identify the global regulatory networks controlling antigen presentation, we employed genome-wide screening in human diffuse large B cell lymphomas (DLBCLs). This approach revealed dozens of genes that positively and negatively modulate MHC-I cell surface expression. Validated genes clustered in multiple pathways including cytokine signaling, mRNA processing, endosomal trafficking, and protein metabolism. Genes can exhibit lymphoma subtype- or tumor-specific MHC-I regulation, and a majority of primary DLBCL tumors displayed genetic alterations in multiple regulators. We established SUGT1 as a major positive regulator of both MHC-I and MHC-II cell surface expression. Further, pharmacological inhibition of two negative regulators of antigen presentation, EZH2 and thymidylate synthase, enhanced DLBCL MHC-I presentation. These and other genes represent potential targets for manipulating MHC-I immunosurveillance in cancers, infectious diseases, and autoimmunity.

Validation and comparison of prognostic values of GNRI, PNI, and CONUT in newly diagnosed diffuse large B cell lymphoma

Diffuse large B cell lymphoma (DLBCL) is the most common type of aggressive non-Hodgkin lymphoma. Emerging evidence indicates that poor nutritional status determined with nutritional indices such as geriatric nutritional risk index (GNRI), prognostic nutritional index (PNI), and controlling nutritional status score (CONUT) was associated with poor prognosis of DLBCL. We conducted this multicenter retrospective study to validate and compare prognostic values of the three indices in 615 newly diagnosed DLBCL patients. The overall survival (OS) in patients with poor nutritional status determined with each of these nutritional indices were significantly inferior compared with that in those without nutritional risks (5-year OS in patients with GNRI < 95.7 and GNRI ≥ 95.7 were 56.4% and 83.5%, P < 0.001; PNI < 42.4 and PNI ≥ 42.4 were 56.1% and 81.0%, P < 0.001; CONUT > 4 and CONUT ≤ 4 were 53.1% and 77.1%, P < 0.001). GNRI and CONUT were independent prognostic predictors for OS (GNRI < 95.7, hazard ratio [HR] 1.83, 95% confidence interval [CI] 1.22-2.74, P = 0.0032; CONUT > 4, HR 1.53, 95% CI 1.05-2.23, P = 0.028) after multivariate analyses. Nutritional status determined with GNRI affected OS more strongly in the patients with nongerminal center B cell-like (nonGCB) DLBCL compared with that in those with GCB-type DLBCL. In conclusion, baseline poor nutritional status determined based on GNRI or CONUT was an independent risk factor of newly diagnosed DLBCL, and GNRI was also useful as an independent prognostic factor for patients with nonGCB-type DLBCL.

Ethionamide Preconditioning Enhances the Proliferation and Migration of Human Wharton's Jelly-Derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are a useful source for cell-based therapy of a variety of immune-mediated diseases, including neurodegenerative disorders. However, poor migration ability and survival rate of MSCs after brain transplantation hinder the therapeutic effects in the disease microenvironment. Therefore, we attempted to use a preconditioning strategy with pharmacological agents to improve the cell proliferation and migration of MSCs. In this study, we identified ethionamide via the screening of a drug library, which enhanced the proliferation of MSCs. Preconditioning with ethionamide promoted the proliferation of Wharton's jelly-derived MSCs (WJ-MSCs) by activating phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinase/extracellular signal-regulated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK)1/2 signaling. Preconditioning with ethionamide also enhanced the migration ability of MSCs by upregulating expression of genes associated with migration, such as C-X-C motif chemokine receptor 4 (CXCR4) and C-X-C motif chemokine ligand 12 (CXCL12). Furthermore, preconditioning with ethionamide stimulated the secretion of paracrine factors, including neurotrophic and growth factors in MSCs. Compared to naïve MSCs, ethionamide-preconditioned MSCs (ETH-MSCs) were found to survive longer in the brain after transplantation. These results suggested that enhancing the biological process of MSCs induced by ethionamide preconditioning presents itself as a promising strategy for enhancing the effectiveness of MSCs-based therapies.

IKKε and TBK1 in diffuse large B-cell lymphoma: A possible mechanism of action of an IKKε/TBK1 inhibitor to repress NF-κB and IL-10 signalling

The IKK‐related kinases, IKKε and TBK1, have essential roles in innate immunity in part through modifying MYD88 signalling from the Toll‐like receptors to regulate NF‐κB signalling. We investigated the expression and function of IKKε and TBK1, in diffuse large B‐cell lymphoma (DLBCL). DLBCL cell lines and patient‐derived xenografts were used to determine their sensitivity to IKKε and TBK1 inhibitors. To understand the function of IKKε and TBK1 secreted factors were determined following administration of inhibitors. Gene expression microarrays were used to determine the transcriptional effects of inhibitors. Higher TBK1 mRNA levels associated with poorer clinical outcome but IKKε and TBK1 were expressed in both germinal centre and non‐germinal centre types of DLBCL. Survival of cell lines Ly10, Ly03 and Pfeiffer, and of some primary human lymphoma cells, was suppressed by a small molecule IKKε/TBK1 inhibitor, DMX3433. DMX3433 reduced IL‐10 production from Ly10 and repressed NF‐κB mediated transcription. Inhibition of IKKε and TBK1 warrants further investigation as a potential therapeutic route to suppress NF‐κB signalling in lymphoma.

Napabucasin, a novel inhibitor of STAT3, inhibits growth and synergises with doxorubicin in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL), the most common type of aggressive non-Hodgkin lymphoma (NHL), has highly heterogeneous molecular characteristics. Although some patients initially respond to standard R-CHOP therapy, 30-40% develop refractory disease or suffer relapse. Signal transducer and activator of transcription 3 (STAT3), which regulates multiple oncogenic processes, has been found to be constitutively activated in various cancers, including DLBCL, suggesting its potential as a therapeutic target. In this study, we determined that 34% (23/69) of DLBCL patients expressed pSTAT3 (Y705) in tumour tissues. Napabucasin, a novel STAT3 inhibitor, exhibited potent cytotoxicity against NHL cell lines in a dose-dependent manner. Mechanistic studies demonstrated that napabucasin induced intrinsic and extrinsic cell apoptosis, downregulated the expression of STAT3 target genes, including the antiapoptotic protein Mcl-1, and regulated the ROS-mediated mitogen-activated protein kinase (MAPK) pathway. Most importantly, in vivo studies revealed the suppressive efficacy of napabucasin as a monotherapy without obvious toxicity. Furthermore, preliminary combination studies of napabucasin with doxorubicin showed significant synergism both in vitro and in vivo. Thus, our studies provide evidence that napabucasin alone or in combination is a promising therapeutic candidate for DLBCL patients.

310 nm UV-LEDs attenuate imiquimod-induced psoriasis-like skin lesions in C57BL/6 mice and inhibit IL-22-induced STAT3 expression in HaCaT cells

Ultraviolet light-emitting diodes (UV-LEDs) are a novel light source for phototherapy. This study aimed to evaluate the therapeutic effects of UV-LEDs on psoriasis. Importantly, 310 nm UV-LEDs have not been studied in psoriasis in vitro and in vivo. Effects due to 310 nm UV-LED and 311 nm narrowband ultraviolet B (NBUVB) irradiation were compared for suppressing IL-22-induced activation of STAT3 expression using cell viability assay, western blotting, and immunocytochemistry. C57BL/6 mice were topically treated with imiquimod (IMQ) for 6 consecutive days and degenerative changes were observed. Test groups were irradiated with a 310 nm UV-LED and 311 nm NBUVB. Phenotypic observations, histopathological examinations, and ELISA were conducted with skin and blood samples. STAT3-dependent IL-22 signalling and effects in keratinocytes are negatively regulated by the 310 nm UV-LED, which significantly ameliorated IMQ-induced psoriasis-like dermatitis development and reduced Th17 cytokine levels (IL-17A, IL-22) in serum and dorsal skin. Histopathological findings showed decreases in epidermal thickness and inflammatory T-cell infiltration in the UV-LED-irradiated groups. Quantitative PCR confirmed a UV radiation energy-dependent decrease in IL-17A and IL-22 mRNA levels. The results demonstrated that UV-LEDs had anti-inflammatory and immunoregulatory effects. So, UV-LED phototherapy inhibits psoriasis development by suppressing STAT3 protein and inflammatory cytokines and could be useful in treating psoriasis.

New Insights into Diffuse Large B-Cell Lymphoma Pathobiology

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma (NHL), accounting for about 40% of all cases of NHL. Analysis of the tumor microenvironment is an important aspect of the assessment of the progression of DLBCL. In this review article, we analyzed the role of different cellular components of the tumor microenvironment, including mast cells, macrophages, and lymphocytes, in the tumor progression of DLBCL. We examined several approaches to confront the available pieces of evidence, whereby three key points emerged. DLBCL is a disease of malignant B cells spreading and accumulating both at nodal and at extranodal sites. In patients with both nodal and extranodal lesions, the subsequent induction of a cancer-friendly environment appears pivotal. The DLBCL cell interaction with mature stromal cells and vessels confers tumor protection and inhibition of immune response while delivering nutrients and oxygen supply. Single cells may also reside and survive in protected niches in the nodal and extranodal sites as a source for residual disease and relapse. This review aims to molecularly and functionally recapitulate the DLBCL–milieu crosstalk, to relate niche and pathological angiogenic constitution and interaction factors to DLBCL progression.

Molecular profiling of primary central nervous system lymphomas - predictive and prognostic value?

PURPOSE OF REVIEW

Primary central nervous system lymphoma (PCNSL) is a rare but aggressive variant of non-Hodgkin lymphoma. The diagnostic gold standard remains the pathologic review of tumor tissue mainly collected though biopsies. The majority of PCNSL are diffuse large B cell lymphoma (DLBCL). Biopsies are invasive procedures, and there have been efforts to develop minimally invasive diagnostic testing using serum and cerebral spinal fluid. This article reviews multiple markers that could potentially serve as future diagnostic tools and predictors of treatment response.

RECENT FINDINGS

Many studies have attempted to classify DLBCL into different subtypes for prognostic purposes using methods such as immunohistochemistry. PCNSL often falls under the activated B-cell-like subgroup, and further genomic sequencing has identified alterations in genes within the B-cell receptor signaling axis at increased frequencies. Two such genes, MYD88 and CD79B, implicate the involvement of the NF-kB (nuclear factor kappa-light-chain enhancer of activated B cells) pathway, and targeted agents to this pathway are currently being used in the treatment of relapsed/refractory PCNSL.

SUMMARY

Although recent genomic profiling of PCNSL has increased the understanding of drivers in this disease and has also led to the introduction of targeted inhibitors, these markers have not yet been used for diagnostic and/or prognostic purposes. Further studies will need to evaluate if they hold great diagnostic potential.

A Dual TLR7/TLR9 Inhibitor HJ901 Inhibits ABC-DLBCL Expressing the MyD88 L265P Mutation

Diffuse large B cell lymphoma (DLBCL) is associated with aggressive clinical cases and poor prognosis despite recent advances in disease treatment. In activated B-cell-like (ABC)-DLBCL, the most severe damaged signaling pathways converge to aberrantly activate the Toll-like receptor (TLR) 7/9/MyD88 pathways, leading to the avoidance of cell death and resistance to chemotherapy. A gain of function mutation in MyD88 (MyD88 L265P) enhanced the NF-κB and JAK-STAT signaling pathways and was associated with dysregulation of TLR signaling in the pathogenesis of ABC-DLBCL. Therefore, inhibition of the TLR signaling network may improve clinical outcomes. In this study, we designed a de novo synthesized oligodeoxynucleotide-based antagonist of TLR7 and TLR9, referred to as HJ901, which competitively binds to TLR7/9. We profiled HJ901 inhibition in various DLBCL cell lines and verified tumor suppression in a xenograft mouse model. We found that HJ901 treatment significantly reduced TLR7- and TLR9-mediated cell proliferation and cytokine production in a time- and dose-dependent manner in various DLBCL cell lines expressing the MyD88 L265P mutation. Moreover, HJ901 prevented tumor growth and downregulated the NF-κB and JAK2-STAT3 signaling pathways in a DLBCL xenograft mouse model with the MyD88 L265P mutation. These results reveal that the anti-tumor effects of the synthesized oligodeoxynucleotide-based antagonist, HJ901, which competitively binds to TLR7/9, may be associated with the downregulation of the NF-κB and JAK2-STAT3 signaling pathways and provide rationale for treating ABC-DLBCL patients with the MyD88 L265P mutation.

S1PR1 as a Novel Promising Therapeutic Target in Cancer Therapy

Sphingosine-1-phosphate (S1P) can regulate several physiological and pathological processes. S1P signaling via its cell surface receptor S1PR1 has been shown to enhance tumorigenesis and stimulate growth, expansion, angiogenesis, metastasis, and survival of cancer cells. S1PR1-mediated tumorigenesis is supported and amplified by activation of downstream effectors including STAT3, interleukin-6, and NF-κB networks. S1PR1 signaling can also trigger various other signaling pathways involved in carcinogenesis including activation of PI3K/AKT, MAPK/ERK1/2, Rac, and PKC/Ca, as well as suppression of cyclic adenosine monophosphate (cAMP). It also induces immunological tolerance in the tumor microenvironment, while the immunosuppressive function of S1PR1 can also lead to the generation of pre-metastatic niches. Some tumor cells upregulate S1PR1 signaling pathways, which leads to drug resistant cancer cells, mainly through activation of STAT3. This signaling pathway is also implicated in some inflammatory conditions leading to the instigation of inflammation-driven cancers. Furthermore, it can also increase survival via induction of anti-apoptotic pathways, for instance, in breast cancer cells. Therefore, S1PR1 and its signaling pathways can be considered as potential anti-tumor therapeutic targets, alone or in combination therapies. Given the oncogenic nature of S1PR1 and its distribution in a variety of cancer cell types along with its targeting advantages over other molecules of this family, S1PR1 should be considered a favorable target in therapeutic approaches to cancer. This review describes the role of S1PR1 in cancer development and progression, specifically addressing breast cancer, glioma, and hematopoietic malignancies. We also discuss the potential use of S1P signaling modulators as therapeutic targets in cancer therapy.

A novel silicone derivative of natural osalmid (DCZ0858) induces apoptosis and cell cycle arrest in diffuse large B-cell lymphoma via the JAK2/STAT3 pathway

Diffuse large B-cell lymphoma (DLBCL) is a highly heterogeneous malignant tumor characterized by diffuse growth. DCZ0858 is a novel small molecule with excellent antitumor effects in DLBCL. This study explored in depth the inhibitory effect of DCZ0858 on DLBCL cell lines. Cell Counting Kit-8 (CCK-8) and plate colony formation assays were used to evaluate cell proliferation levels. Flow cytometry was employed to analyze apoptosis and the cell cycle, and western blotting was used to quantify the expression of cell cycle regulators. The results indicated that DCZ0858 inhibited cell growth in a concentration-dependent and time-dependent manner while inducing no significant toxicity in normal cells. Moreover, DCZ0858 initiated cell apoptosis via both internal and external apoptotic pathways. DCZ0858 also induced cell cycle arrest in the G0/G1 phase, thereby controlling cell proliferation. Further investigation of the molecular mechanism showed that the JAK2/STAT3 pathway was involved in the DCZ0858-mediated antitumor effects and that JAK2 was the key target for DCZ0858 treatment. Knockdown of JAK2 partly weakened the DCZ0858-mediated antitumor effect in DLBCL cells, while JAK2 overexpression strengthened the effect of DCZ0858 in DLBCL cells. Moreover, a similar antitumor effect was observed for DCZ0858 and the JAK2 inhibitor ruxolitinib, and combining the two could significantly enhance cancer-suppressive signaling. Tumor xenograft models showed that DCZ0858 inhibited tumor growth in vivo and had low toxicity in important organs, findings that were consistent with the in vitro data. In summary, DCZ0858 is a promising drug for the treatment of DLBCL.

Natural pseurotins and analogs thereof inhibit activation of B-cells and differentiation into the plasma cells

BACKGROUND

The frequency of allergic diseases is constantly rising. Dysregulated production of isotype E immunoglobulins is one of the key factors behind allergic reactions and its modulation is therefore an important target for pharmacological intervention. Natural products of the pseurotin family were reported to be inhibitors of IgE production in B-cells. Mechanistic details underlying these effects are however not well understood.

PURPOSE

In the present study, we synthesized new analogs of natural pseurotins and extensively investigated their inhibitory effects on activation, proliferation and differentiation of B-cells, as well as on the production of IgE.

STUDY DESIGN

Effects of two natural pseurotins (pseurotins A and D) and a collection of fully synthetic pseurotin analogs were studied on mouse B-cells stimulated by the combination of IL-4 and E. coli lipopolysaccharide. The IgE production was determined along with cell viability and cell proliferation. The phosphorylation of selected members of the STAT transcription factor family was subsequently investigated. Finally, the in vivo effect of pseurotin D on the ovalbumin-induced delayed type hypersensitivity response was tested in mice.

RESULTS

We discovered that several fully synthetic pseurotin analogs were able to decrease the production of IgE in stimulated B-cells with potency comparable to that of pseurotins A and D. We found that the two natural pseurotins and the active synthetic analogs inhibited the phosphorylation of STAT3, STAT5 and STAT6 proteins in stimulated B-cells, resulting in the inhibition of B-cell proliferation and differentiation into the plasma cells. In vivo, pseurotin D decreased ovalbumin-induced foot pad edema.

CONCLUSION

Our results advance the current mechanistic understanding of the pseurotin-induced inhibition of IgE production in B-cells by linking the effect to STAT signaling, and associated modulation of B-cell proliferation and differentiation. Together with our finding that structurally simpler pseurotin analogs were able to reproduce the effects of natural pseurotins, the presented work has implications for the future research on these secondary metabolites in the context of allergic diseases.

Bone Marrow Stromal Cells Drive Key Hallmarks of B Cell Malignancies

All B cell leukaemias and a substantial fraction of lymphomas display a natural niche residency in the bone marrow. While the bone marrow compartment may only be one of several sites of disease manifestations, the strong clinical significance of minimal residual disease (MRD) in the bone marrow strongly suggests that privileged niches exist in this anatomical site favouring central elements of malignant transformation. Here, the co-existence of two hierarchical systems, originating from haematopoietic and mesenchymal stem cells, has extensively been characterised with regard to regulation of the former (blood production) by the latter. How these two systems cooperate under pathological conditions is far less understood and is the focus of many current investigations. More recent single-cell sequencing techniques have now identified an unappreciated cellular heterogeneity of the bone marrow microenvironment. How each of these cell subtypes interact with each other and regulate normal and malignant haematopoiesis remains to be investigated. Here we review the evidences of how bone marrow stroma cells and malignant B cells reciprocally interact. Evidently from published data, these cell-cell interactions induce profound changes in signalling, gene expression and metabolic adaptations. While the past research has largely focussed on understanding changes imposed by stroma- on tumour cells, it is now clear that tumour-cell contact also has fundamental ramifications for the biology of stroma cells. Their careful characterisations are not only interesting from a scientific biological viewpoint but also relevant to clinical practice: Since tumour cells heavily depend on stroma cells for cell survival, proliferation and dissemination, interference with bone marrow stroma-tumour interactions bear therapeutic potential. The molecular characterisation of tumour-stroma interactions can identify new vulnerabilities, which could be therapeutically exploited.

Signal Pathways and Therapeutic Prospects of Diffuse Large B Cell Lymphoma

BACKGROUND

Diffuse Large B Cell Lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma which is heterogeneous both clinically and morphologically. Over the past decades, significant advances have been made in the understanding of the molecular genesis, leading to the identification of multiple pathways and molecules that can be targeted for clinical benefit.

OBJECTIVE

The current review aims to present a brief overview of signal pathways of DLBCL, which mainly focus on B-cell antigen Receptor (BCR), Nuclear Factor-κB (NF-κB), Phosphatidylinositol-3-Kinase (PI3K) - protein kinase B (Akt) - mammalian Target of Rapamycin (mTOR), Janus Kinase (JAK) - Signal Transducer and Activator (STAT), Wnt/β-catenin, and P53 pathways.

METHODS

Activation of signal pathways may contribute to the generation, development, chemotherapy sensitivity of DLBCL, and expression of pathway molecules is associated with the prognosis of DLBCL. Some agents targeting these pathways have been proved effective and relevant clinical trials are in progress. These agents used single or combined with chemotherapy/each other might raise the possibility of improving clinical outcomes in DLBCL.

CONCLUSION

This review presents several signal pathways of DLBCL and targeted agents had a tendency to improve the curative effect, especially in high-risk or relapsed/refractory DLBCL.

Pharmacological Inhibition of Oncogenic STAT3 and STAT5 Signaling in Hematopoietic Cancers

Signal Transducer and Activator of Transcription (STAT) 3 and 5 are important effectors of cellular transformation, and aberrant STAT3 and STAT5 signaling have been demonstrated in hematopoietic cancers. STAT3 and STAT5 are common targets for different tyrosine kinase oncogenes (TKOs). In addition, STAT3 and STAT5 proteins were shown to contain activating mutations in some rare but aggressive leukemias/lymphomas. Both proteins also contribute to drug resistance in hematopoietic malignancies and are now well recognized as major targets in cancer treatment. The development of inhibitors targeting STAT3 and STAT5 has been the subject of intense investigations during the last decade. This review summarizes the current knowledge of oncogenic STAT3 and STAT5 functions in hematopoietic cancers as well as advances in preclinical and clinical development of pharmacological inhibitors.

STAT3 Activation and Oncogenesis in Lymphoma

Signal transducer and activator of transcription 3 (STAT3) is an important and the most studied transcription factor in the Janus kinase (JAK)/STAT signaling pathway. STAT3 mediates the expression of various genes that play a critical role in many cellular and biological processes, such as cell proliferation, survival, differentiation, migration, angiogenesis, and inflammation. STAT3 and associated JAKs are activated and tightly regulated by a variety of cytokines and growth factors and their receptors in normal immune responses. However, abnormal expression of STAT3 leads to its constitutive activation, which promotes malignant transformation and tumor progression through oncogenic gene expression in numerous human cancers. Human lymphoma is a heterogeneous malignancy of T and B lymphocytes. Constitutive signaling by STAT3 is an oncogenic driver in several types of B-cell lymphoma and most of T-cell lymphomas. Aberrant STAT3 activation can also induce inappropriate expression of genes involved in tumor immune evasion such as PD-L1. In this review, we focus on the oncogenic role of STAT3 in human lymphoma and highlight potential therapeutic intervention by targeting JAK/STAT3 signaling.

The potential role of glycogen metabolism in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a common and aggressive form of non-Hodgkin lymphoma that may become refractory to available standard therapies, resulting in the need for the development of novel therapeutic targets. Increased metabolic activity of DLBCL tumor cells associated with high expression of glycolysis related proteins, such as glucose transporters and hexokinases, have already been described and indicates a pivotal role for glucose and glycogen metabolism in the malignant progression of the disease. Moreover, several enzymes involved in glycolysis and glycogen metabolism, including hexokinases and glycogen synthase kinase-3, are key molecules in mediating cell survival signaling, indicating that glucose/glycogen metabolism is tightly linked to the cell survival and can potentially be targeted for therapeutic purposes in DLBCL. In this review, we provide a summary of glycogen and glucose metabolism and discuss their significance in the metabolic reprograming that leads to cell survival and proliferation in DLBCL.

Precision Medicine in Lymphoma by Innovative Instrumental Platforms

In recent years, many efforts have been addressed to the growing field of precision medicine in order to offer individual treatments to every patient on the basis of his/her genetic background. Formerly adopted to achieve new disease classifications as it is still done, innovative platforms, such as microarrays, genome-wide association studies (GWAS), and next generation sequencing (NGS), have made the progress in pharmacogenetics faster and cheaper than previously expected. Several studies in lymphoma patients have demonstrated that these platforms can be used to identify biomarkers predictive of drug efficacy and tolerability, discovering new possible druggable proteins. Indeed, GWAS and NGS allow the investigation of the human genome, finding interesting associations with putative or unexpected targets, which in turns may represent new therapeutic possibilities. Importantly, some objective difficulties have initially hampered the translation of findings in clinical routines, such as the poor quantity/quality of genetic material or the paucity of targets that could be investigated at the same time. At present, some of these technical issues have been partially solved. Furthermore, these analyses are growing in parallel with the development of bioinformatics and its capabilities to manage and analyze big data. Because of pharmacogenetic markers may become important during drug development, regulatory authorities (i.e., EMA, FDA) are preparing ad hoc guidelines and recommendations to include the evaluation of genetic markers in clinical trials. Concerns and difficulties for the adoption of genetic testing in routine are still present, as well as affordability, reliability and the poor confidence of some patients for these tests. However, genetic testing based on predictive markers may offers many advantages to caregivers and patients and their introduction in clinical routine is justified.

RNAscope dual ISH-IHC technology to study angiogenesis in diffuse large B-cell lymphomas

Diffuse large B-cell lymphomas (DLBCLs) are the most common types of Non-Hodgkin's lymphomas and are highly heterogeneous in terms of phenotype and treatment response. The natural course of DLBCLs tumor progression is featured by a flow of events leading to the enhancement of proliferative and invasive capabilities and, therefore, towards the establishment of a more aggressive phenotype. Angiogenesis is a constant hallmark of DLBCLs progression, has prognostic potential and promote DLBCLs dissemination. The study of DLBCLs angiogenesis mechanisms, and the tumor endothelium characterization, will allow us to identify new prognostic/predictive biomarkers to proper patient selection to antiangiogenic treatment. In our previous work, by RNAscope technology, we have demonstrated that Janus kinase (Jak) and signal transducer activator of transcription pathway (STAT) is one of the proangiogenic pathways activated in DLBCLs and it drives neoangiogenesis occurred by vasculogenesis mechanism. Here, we describe a detailed protocol to perform RNAscope technology alone and in combination with immunohistochemistry (called dual RNAscope ISH-IHC) in DLBCLs formalin-fixed, paraffin-embedded sections. We propose dual ISH-IHC as an extremely powerful method to study angiogenesis in DLBCLs, because it allows one to answer important biological questions that are difficult to address using other single methods.