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Purpose: We report the case of an adult patient diagnosed with Hodgkin's lymphoma who was scheduled for Pembrolizumab after failure of standard therapy. After three well-tolerated courses of Pembrolizumab, a PET scan showed a favorable outcome and a fourth course of Pembrolizumab was started. Unexpectedly, extremely severe toxicities (i.e., autoimmune peripheral hypothyroidism, rhabdomyolysis and severe acute renal failure) occurred after this last course, requiring transfer to the intensive care unit. Methods: Therapeutic drug monitoring was performed to measure residual Pembrolizumab levels at intervals from the last dose (i.e., 120 and then 170 days), as well as pharmacogenetics investigations on the FCγR gene. Results: Pembrolizumab plasma concentrations that were still pharmacologically active months after the last administration, suggesting impaired elimination of Pembrolizumab in this patient. Further pharmacokinetic modeling based on the population approach showed that both half-life (47.8 days) and clearance (0.12 L/day) values were significantly different from the standard values usually reported in patients. Further in silico simulations showed that pharmacologically active concentrations of Pembrolizumab were maintained for up to 136 days after the last dose. The search for possible polymorphisms affecting the genes coding for FCγR (i.e., rs1801274 on FCGR2A and rs396991 on FCGR3A gene) was negative. Further TDM showed that Pembrolizumab could be detected up to 263 days after the last administration. Conclusion: This case report suggests that persistent overexposure in plasma could lead to life-threatening toxicities with Pembrolizumab. [ABSTRACT FROM AUTHOR]

Epstein-Barr Virus (EBV) infection is closely associated with the development of lymphoma, as it plays a significant role in the malignant transformation of lymphocytes. The expression of programmed death-1 (PD-1), which binds to PD-L1 in tumor cells, can lead to immune evasion by lymphoma cells and promote tumor progression. In this study, immortalized B lymphoblastoid cell lines (B-LCLs) positive for EBV-specific proteins were established from human peripheral mononuclear cells (PBMCs) using EBV induction along with CpG-ODN 2006 and cyclosporin A. EBV-specific T cells (EBVST) were generated by multiple immunizations of CD3+ T lymphocytes using irradiated B-LCLs. Flow cytometry analysis confirmed the activation of EBVST through the detection of CD3+, CD4+, and CD8+ markers. Co-incubation of EBVST with EBV-positive B lymphocyte cell lines resulted in the secretion of perforin by EBVST, leading to granzyme B-mediated cell death and an increase in LDH levels. Silencing PD-1 in EBVST cells enhanced perforin production, increased granzyme B release, and upregulated cell death in co-incubated B lymphocytes. In a nude mice tumor transplantation model, silencing PD-1 in combination with EBV-specific killer T cells exhibited the maximum inhibition of B-lymphoblastoma. This treatment upregulated the expression of proteins associated with apoptosis and immune response, while inhibiting anti-apoptotic protein expression in tumor tissues. Silencing PD-1 also increased the infiltration of EBV-specific killer T cells in the tumor tissues. Overall, PD-1 silencing enhanced the tumor targeting effect of EBV-specific killer T cells on EBV-infected B lymphocytes and attenuated the immune escape effect mediated by the PD-1 pathway.

Nonviral transposon piggyBac (PB) and lentiviral (LV) vectors have been used to deliver chimeric antigen receptor (CAR) to T cells. To understand the differences in the effects of PB and LV on CAR T-cell functions, a CAR targeting CD19 was cloned into PB and LV vectors, and the resulting pbCAR and lvCAR were delivered to T cells to generate CD19pbCAR and CD19lvCAR T cells. Both CD19CAR T-cell types were strongly cytotoxic and secreted high IFN-γ levels when incubated with Raji cells. TNF-α increased in CD19pbCAR T cells, whereas IL-10 increased in CD19lvCAR T cells. CD19pbCAR and CD19lvCAR T cells showed similar strong anti-tumor activity in Raji cell-induced mouse models, slightly reducing mouse weight while enhancing mouse survival. High, but not low or moderate, concentrations of CD19pbCAR T cells significantly inhibited Raji cell-induced tumor growth in vivo. These CD19pbCAR T cells were distributed mostly in mesenteric lymph nodes, bone marrow of the femur, spleen, kidneys, and lungs, specifically accumulating at CD19-rich sites and CD19-positive tumors, with CAR copy number being increased on day 7. These results indicate that pbCAR has its specific activities and functions in pbCAR T cells, making it a valuable tool for CAR T-cell immunotherapy. [ABSTRACT FROM AUTHOR]

Nonviral transposon piggyBac (PB) and lentiviral (LV) vectors have been used to deliver chimeric antigen receptor (CAR) to T cells. To understand the differences in the effects of PB and LV on CAR T-cell functions, a CAR targeting CD19 was cloned into PB and LV vectors, and the resulting pbCAR and lvCAR were delivered to T cells to generate CD19pbCAR and CD19lvCAR T cells. Both CD19CAR T-cell types were strongly cytotoxic and secreted high IFN-γ levels when incubated with Raji cells. TNF-α increased in CD19pbCAR T cells, whereas IL-10 increased in CD19lvCAR T cells. CD19pbCAR and CD19lvCAR T cells showed similar strong anti-tumor activity in Raji cell-induced mouse models, slightly reducing mouse weight while enhancing mouse survival. High, but not low or moderate, concentrations of CD19pbCAR T cells significantly inhibited Raji cell-induced tumor growth in vivo. These CD19pbCAR T cells were distributed mostly in mesenteric lymph nodes, bone marrow of the femur, spleen, kidneys, and lungs, specifically accumulating at CD19-rich sites and CD19-positive tumors, with CAR copy number being increased on day 7. These results indicate that pbCAR has its specific activities and functions in pbCAR T cells, making it a valuable tool for CAR T-cell immunotherapy.

Turk J. Biol. 44, (1), 1-14. 10.3906/biy-1908-23 3 Fuertes, T., Ramiro, A. R., de Yebenes, V. G., (2020). miRNA-Based Therapies in B Cell Non-hodgkin Lymphoma. Keywords: B lymphoma; tumor microenvironment; NHL - Non-Hodgkin lymphomas; immune cells; Epigenetic alteration EN B lymphoma tumor microenvironment NHL - Non-Hodgkin lymphomas immune cells Epigenetic alteration 1 3 3 05/23/22 20220519 NES 220519 Non-Hodgkin B Lymphoma (B-NHL) is the seventh most common cancer of the lymphatic system. B lymphoma, tumor microenvironment, NHL - Non-Hodgkin lymphomas, immune cells, Epigenetic alteration Genetic Alterations in B Cell Lymphoma Subtypes as Potential Biomarkers for Noninvasive Diagnosis, Prognosis, Therapy, and Disease Monitoring. [Extracted from the article]

Epstein-Barr Virus (EBV) infection is closely associated with the development of lymphoma, as it plays a significant role in the malignant transformation of lymphocytes. The expression of programmed death-1 (PD-1), which binds to PD-L1 in tumor cells, can lead to immune evasion by lymphoma cells and promote tumor progression. In this study, immortalized B lymphoblastoid cell lines (B-LCLs) positive for EBV-specific proteins were established from human peripheral mononuclear cells (PBMCs) using EBV induction along with CpG-ODN 2006 and cyclosporin A. EBV-specific T cells (EBVST) were generated by multiple immunizations of CD3 + T lymphocytes using irradiated B-LCLs. Flow cytometry analysis confirmed the activation of EBVST through the detection of CD3 + , CD4 + , and CD8 + markers. Co-incubation of EBVST with EBV-positive B lymphocyte cell lines resulted in the secretion of perforin by EBVST, leading to granzyme B-mediated cell death and an increase in LDH levels. Silencing PD-1 in EBVST cells enhanced perforin production, increased granzyme B release, and upregulated cell death in co-incubated B lymphocytes. In a nude mice tumor transplantation model, silencing PD-1 in combination with EBV-specific killer T cells exhibited the maximum inhibition of B-lymphoblastoma. This treatment upregulated the expression of proteins associated with apoptosis and immune response, while inhibiting anti-apoptotic protein expression in tumor tissues. Silencing PD-1 also increased the infiltration of EBV-specific killer T cells in the tumor tissues. Overall, PD-1 silencing enhanced the tumor targeting effect of EBV-specific killer T cells on EBV-infected B lymphocytes and attenuated the immune escape effect mediated by the PD-1 pathway., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Inc.)

Primary mediastinal B-cell lymphoma (PMBL) is a distinct B-cell lymphoma subtype with unique clinicopathological and molecular features. PMBL cells are characterised by several genetic abnormalities that conduct to the constitutive activation of the Janus kinase 2/signal transducer and activator of transcription 6 (JAK2/STAT6) signalling pathway. Among recurrent genetic changes in PMBL, we previously reported that the XPO1 gene encoding exportin 1 that controls the nuclear export of cargo proteins and RNAs, is mutated (p.E571K) in about 25% of PMBL cases. We therefore hypothesized that STAT6 could be a cargo of XPO1 and that STAT6 cytoplasm/nucleus shuttle could be altered in a subset of PMBL cells. Using immunocytochemistry techniques as well as the proximity ligation assay, we showed that STAT6 bound XPO1 in PBML cell lines and in HEK-293 cells genetically engineered to produce STAT6. Moreover, XPO1-mediated export of STAT6 occurs in cells expressing either a wild-type or the E571K mutated XPO1 protein. [ABSTRACT FROM AUTHOR]

High plasma lactate is associated with poor prognosis of many malignancies, but its role in virally mediated cancer progression and underlying molecular mechanisms are unclear. Epstein-Barr virus (EBV), the first human oncogenic virus, causes several cancers, including B-cell lymphoma. Here, we report that lactate dehydrogenase A (LDH-A) expression and lactate production are elevated in EBV-immortalized B lymphoblastic cells, and lactic acid (LA; acidic lactate) at low concentration triggers EBV-infected B-cell adhesion, morphological changes and proliferation in vitro and in vivo. Moreover, LA-induced responses of EBV-infected B cells uniquely occurs in viral latency type III, and it is dramatically associated with the inhibition of global viral microRNAs, particularly the miR-BHRF1 cluster, and the high expression of SMAD3, JUN, and COL1A genes. The introduction of miR-BHRF1-1 blocks the LA-induced effects of EBV-infected B cells. Thus, this may be a novel mechanism to explain EBV-immortalized B lymphoblastic cell malignancy in an LA microenvironment. IMPORTANCE The tumor microenvironment is complicated, and lactate, which is created by cell metabolism, contributes to an acidic microenvironment that facilitates cancer progression. However, how LA operates in virus-associated cancers is unclear. Thus, we studied how EBV (the first tumor virus identified in humans; it is associated with many cancers) upregulates the expression of LDH-A and lactate production in B lymphoma cells. Elevated LA induces adhesion and the growth of EBVinfected B cells by inhibiting viral microRNA transcription. Thus, we offer a novel understanding of how EBV utilizes an acidic microenvironment to promote cancer development. [ABSTRACT FROM AUTHOR]

OBJECTIVE: B lymphoma is a type of malignant tumor originating from the lymphatic hematopoietic system. The pathogenesis and treatment methods are not clear. The change of oxidative stress is closely related to the cell DNA damage and cell apoptosis, which may be served as a target for cancer treatment. This study aims to illustrate the role of oxidative stress in the regulation of B lymphocytoma. PATIENTS AND METHODS: The tumor tissue was collected from patients with B lymphocytoma. The p66shc level was detected by Western blot. Hydrogen peroxide (H2O2) was assessed by the kit. The oxidative stress model of B lymphoma cell was established by H2O2 treatment. ROS inhibitor or RNAi was used to regulate ROS level. ROS level was determined by flow cytometry. 8-OHdG level (DNA damage product) was tested by the kit. Cell apoptosis was evaluated by annexin V-PI. RESULTS: P66shc expression was significantly reduced, while H2O2 production was significantly decreased in the tumor tissue of B lymphoma compared with adjacent normal control. H2O2 stimulation markedly elevated ROS level and p66shc expression (p < 0.05), accompanied by the aggravation of DNA damage and increase of apoptosis. ROS inhibitor or p66shc RNAi treatment significantly attenuated DNA damage and declined cell apoptosis (p < 0.05). CONCLUSIONS: ROS production promoted p66shc expression, induced DNA damage, and facilitated cell apoptosis. Upregulation of p66shc by oxidative stress could be treated as a new therapeutic target for B lymphoma. [ABSTRACT FROM AUTHOR]

TRAF3, a critical regulator of B cell survival, was recently recognized as a tumor suppressor gene in B lymphocytes. Specific deletion of TRAF3 from B lymphocytes leads to spontaneous development of marginal zone lymphomas (MZL) or B1 lymphomas in mice. To identify novel oncogenes and tumor suppressive genes involved in malignant transformation of TRAF3-deficient B cells, we performed a microarray analysis to identify genes differentially expressed in TRAF3−/− mouse splenic B lymphomas. We have identified 160 up-regulated genes and 244 down-regulated genes in TRAF3−/−B lymphomas as compared to littermate control splenocytes. Here we describe the samples, quality control assessment, as well as the data analysis methods in detail for the transcriptomic profiling study. Data are archived at NIH GEO with accession number GSE48818.

P18F3-based bi-modular fusion proteins (BMFPs), designed to re-direct pre-existing anti-Epstein-Barr virus (EBV) endogenous polyclonal antibodies towards defined target cells, demonstrated efficient biological activity in a mouse tumor model and could potentially represent a universal and versatile platform to develop novel therapeutics against a broad range of diseases. This protocol provides step-by-step instructions for expressing scFv 2H7 -P18F3, a BMFP targeting human CD20, in Escherichia coli (SHuffle ® ), and for purifying soluble proteins using a two-step process, namely immobilized metal affinity chromatography (IMAC) followed by size exclusion chromatography. This protocol can also be used for expression and purification of other BMFPs with alternative binding specificities., Competing Interests: Competing interestsBG and AC are inventors on a patent application related to this protocol filed by Institut National de la Transfusion Sanguine, Centre National de la Recherche Scientifique (CNRS), Inserm, Université de Paris (now universtité Paris Cité) (no. WO2017103020A1, filed 25 December 2015, published 22 June 2017). The authors declare that they have no other competing interests., (Copyright © 2023 The Authors; exclusive licensee Bio-protocol LLC.)

Tumours can escape immune destruction through the development of antigen loss variants and loss of antigen processing/presentation pathways thereby rendering them invisible to T cells. Alternatively, mechanisms of peripheral T-cell tolerance that would normally be important for protection from the development of autoimmunity may also be co-opted to i) generate an immuno-inhibitory tumour environment, ii) promote development of regulatory cell populations or iii) cell-intrinsically inactivate tumour-specific T cells. Emerging evidence suggests that T-cell function is impaired in haematological malignancies which may manifest from cognate interactions between T cells and the tumour. The immunological synapse forms the cognate T-cell and antigen-presenting cell interaction and is the site where key signalling events, including those delivered by co-inhibitory receptors, that determine the fate of T cells occur. Here we review evidence that events at the immune synapse between T cells and malignant B cells and alterations in immune synapse function may contribute to loss of T-cell function in B-cell malignancies.

Bortezomib, a clinical drug for multiple myeloma (MM) and mantle cell lymphoma, exhibits complex mechanisms of action, which vary depending on the cancer type and the critical genetic alterations of each cancer. Here we investigated the signaling mechanisms of bortezomib in mouse B lymphoma and human MM cells deficient in a new tumor suppressor gene, TRAF3. We found that bortezomib consistently induced up-regulation of the cell cycle inhibitor p21(WAF1) and the pro-apoptotic protein Noxa as well as cleavage of the anti-apoptotic protein Mcl-1. Interestingly, bortezomib induced the activation of NF-κB1 and the accumulation of the oncoprotein c-Myc, but inhibited the activation of NF-κB2. Furthermore, we demonstrated that oridonin (an inhibitor of NF-κB1 and NF-κB2) or AD 198 (a drug targeting c-Myc) drastically potentiated the anti-cancer effects of bortezomib in TRAF3-deficient malignant B cells. Taken together, our findings increase the understanding of the mechanisms of action of bortezomib, which would aid the design of novel bortezomib-based combination therapies. Our results also provide a rationale for clinical evaluation of the combinations of bortezomib and oridonin (or other inhibitors of NF-κB1/2) or AD 198 (or other drugs targeting c-Myc) in the treatment of lymphoma and MM, especially in patients containing TRAF3 deletions or relevant mutations. [ABSTRACT FROM AUTHOR]

Background Identification of novel genetic risk factors is imperative for a better understanding of B lymphomagenesis and for the development of novel therapeutic strategies. TRAF3, a critical regulator of B cell survival, was recently recognized as a tumor suppressor gene in B lymphocytes. The present study aimed to identify novel oncogenes involved in malignant transformation of TRAF3-deficient B cells. Methods We used microarray analysis to identify genes differentially expressed in TRAF3-/- mouse splenic B lymphomas. We employed lentiviral vector-mediated knockdown or overexpression to manipulate gene expression in human multiple myeloma (MM) cell lines. We analyzed cell apoptosis and proliferation using flow cytometry, and performed biochemical studies to investigate signaling mechanisms. To delineate protein-protein interactions, we applied affinity purification followed by mass spectrometry-based sequencing. Results We identified mutated in colorectal cancer (MCC) as a gene strikingly up-regulated in TRAF3-deficient mouse B lymphomas and human MM cell lines. Aberrant up-regulation of MCC also occurs in a variety of primary human B cell malignancies, including non-Hodgkin lymphoma (NHL) and MM. In contrast, MCC expression was not detected in normal or premalignant TRAF3-/- B cells even after treatment with B cell stimuli, suggesting that aberrant up-regulation of MCC is specifically associated with malignant transformation of B cells. In elucidating the functional roles of MCC in malignant B cells, we found that lentiviral shRNA vector-mediated knockdown of MCC induced apoptosis and inhibited proliferation in human MM cells. Experiments of knockdown and overexpression of MCC allowed us to identify several downstream targets of MCC in human MM cells, including phospho-ERK, c- Myc, p27, cyclin B1, Mcl-1, caspases 8 and 3. Furthermore, we identified 365 proteins (including 326 novel MCC-interactors) in the MCC interactome, among which PARP1 and PHB2 were two hubs of MCC signaling pathways in human MM cells. Conclusions Our results indicate that in sharp contrast to its tumor suppressive role in colorectal cancer, MCC functions as an oncogene in B cells. Our findings suggest that MCC may serve as a diagnostic marker and therapeutic target in B cell malignancies, including NHL and MM. [ABSTRACT FROM AUTHOR]

Abstract: Using a mouse model with the tumor suppressor TRAF3 deleted from B cells, we identified Sox5 as a gene strikingly up-regulated in B lymphomas. Sox5 proteins were not detected in normal or premalignant TRAF3−/− B cells even after treatment with B cell stimuli. The Sox5 expressed in TRAF3−/− B lymphomas represents a novel isoform of Sox5, and was localized in the nucleus of malignant B cells. Overexpression of Sox5 inhibited cell cycle progression, and up-regulated the protein levels of p27 and β-catenin in human multiple myeloma cells. Together, our findings indicate that Sox5 regulates the proliferation of malignant B cells. [Copyright &y& Elsevier]

Background: Human Immunodeficiency Virus Type I (HIV-1) infection is associated with a high incidence of B-cell lymphomas. The role of HIV in these lymphomas is unclear and currently there are no valid in vivo models for better understanding HIV-related lymphomagenesis. Transgenic (Tg) 26 mice have a 7.4-kb pNL4-3 HIV-1 provirus lacking a 3.1-kb sequence encompassing parts of the gag-pol region. Approximately 15% of these HIV Tg mice spontaneously develop lymphoma with hallmark pre-diagnostic markers including skin lesions, diffuse lymphadenopathy and an increase in pro-inflammatory serum cytokines. Here we describe the phenotypic and molecular characteristics of the B cell leukemia/lymphoma in the Tg mice. Results: The transformed B cell population consists of CD19+pre-BCR+CD127+CD43+CD93+ precursor B cells. The tumor cells are clonal and characterized by an increased expression of several cellular oncogenes. Expression of B cell-stimulatory cytokines IL-1а, IL-6, IL-10, IL-12p40, IL-13 and TNFα and HIV proteins p17, gp120 and nef were elevated in the Tg mice with lymphoma. Conclusions: Increased expression of HIV proteins and the B-cell stimulatory factors is consistent with the interpretation that one or more of these factors play a role in lymphoma development. The lymphomas share many similarities with those occurring in HIV/AIDS+ patients and may provide a valuable model for understanding AIDS-related lymphomagenesis and elucidating the role played by HIV-1. [ABSTRACT FROM AUTHOR]

Abstract: Dendritic cells (DCs) pulsed by tumor antigens have been widely used as tumor vaccines to specifically trigger the cytotoxicity of CD8+ T cells. But the tumor microenviroment with enriched immunosuppressants hampered DC maturation and co-stimulation. CD40/CD40L signaling, one of the most important co-stimulatory molecules is capable of effectively skewing the immune response by promoting DCs maturation and co-stimulation. To establish a novel specific immunotherapeutic approach for the use of DC vaccine in the treatment of B lymphoma, hu-SCID mice bearing B lymphoma were vaccinated by different combination of tumor antigen pulsed DC or imDC vaccines and immune-enhancing agencies such as agonist CD40mAb and T cells. The results of immature DCs combined with agonistic CD40mAb were encouraging with achievement of tumor regression and induction of antigen-specific immune responses. These findings demonstrated the potential utility of imDC-based tumor vaccination combining with agonistic CD40mAb in the treatment of malignant lymphoma. [Copyright &y& Elsevier]

Elevated expression of the antiapoptotic protein Bfl-1 (A1) was previously reported in several cancer cell lines. Recently, molecular profiling of large B-cell lymphoma identified Bfl-1 as a gene signature in ‘OxPhos’ diffuse large B-cell lymphoma subtype and in primary mediastinal large B-cell lymphoma, suggesting that in addition to Bcl-2, Bcl-xL and Mcl-1, Bfl-1 may be a relevant target in the design of new strategies for cancer therapy. Using short hairpin RNA strategy, we show here that Bfl-1 silencing in one lymphoblastoid B-cell line and in two diffuse large B-cell lymphoma cell lines potently induces their apoptosis and sensitizes those cell lines to anti-CD20 (Rituximab)-mediated cell death as well as to apoptosis induced by chemotherapeutic molecules such as doxorubicin, vincristine, cisplatin and fludarabine. These results demonstrate for the first time that Bfl-1 is an essential protein for survival of malignant B cells and suggest Bfl-1 may represent a potential target for future drug development against B cell lymphoma.Oncogene (2007) 26, 5828–5832; doi:10.1038/sj.onc.1210363; published online 12 March 2007 [ABSTRACT FROM AUTHOR]

ICOS-L, a newly identified member of B7 superfamily, plays an important role in immune responses. In this article, we report on two novel mouse anti-human ICOS-L monoclonal antibodies (mAbs) named as 11C4 and 12B11, whose specificities were verified by methods of flow cytometry, western blotting, and epitope competition assay. The two mAbs bound to distinct ICOS-L epitopes on B cells. Interestingly, mAb 11C4 could well recognize ICOS-L molecule on activated T cells and Jurkat cell lines, which is different from commercial anti-ICOS-L mAb (clone number MIH12) and the other mAb 12B11. In addition, we found that the expression of ICOS-L molecule was only detected on the surface of immature monocyte-derived dendritic cells (Mo-DCs) and was sharply decreased after induction of mature Mo-DCs activated by tumor necrosis factor-α or CD40. Furthermore, we showed that 11C4 could effectively suppress the maturation of Mo-DCs in vitro as evidenced by the low expression of CD80, CD86, CD83, and human leukocyte antigen-DR, which suggested that ICOS-L may be involved in the maturation of Mo-DCs. Using immunohistochemistry staining with mAb 11C4, the expression of ICOS-L was found in B lymphoma tissues and thyroid tissues from the Grave’s disease but not in thyroid adenoma and normal thyroid tissues. [ABSTRACT FROM AUTHOR]

The protein levels of β-catenin are tightly regulated by the ubiquitin/proteasome system. We provide evidence that two distinct ubiquitin-dependent degradation pathways for β-catenin are active in the same Burkitt's lymphoma cells: Along with the classical glycogen-synthase kinase 3β-dependent destruction machinery, degradation of β-catenin through seven in absentia homolog 1 (Siah-1) ubiquitin ligase is functional in these cells. We show that inhibition of endogenous Siah-1 stabilizes and activates β-catenin in B cells. The principal Epstein-Barr virus oncoprotein, latent membrane protein 1, is involved in β-catenin up-regulation, and expression of latent membrane protein 1 in B lymphoma cells is associated with decreased Siah-1 RNA and protein levels. Thus, we demonstrate the significance of the endogenous Siah-1-dependent ubiquitin/proteasome pathway for β-catenin degradation in malignant human cells and its regulation by a viral oncogene. [ABSTRACT FROM AUTHOR]

Mutations in p53, a tumor suppressor gene, occur in more than half of human cancers. Therefore, we tested the hypothesis that jasmonates (novel anticancer agents) can induce death in mutated p53-expressing cells. Two clones of B-lymphoma cells were studied, one expressing wild-type (wt) p53 and the other expressing mutated p53. Jasmonic acid and methyl jasmonate (0.25-3 mM) were each equally cytotoxic to both clones, whereas mutant p53-expressing cells were resistant to treatment with the radiomimetic agent neocarzinostatin and the chemotherapeutic agent bleomycin. Neocarzinostatin and bleomycin induced an elevation in the p53 levels in wt p53-expressing cells, whereas methyl jasmonate did not. Methyl jasmonate induced mostly apoptotic death in the wt p53-expressing cells, while no signs of early apoptosis were detected in mutant p53-expressing cells. In contrast, neocarzinostatin and bleomycin induced death only in wt p53-expressing cells, in an apoptotic mode. Methyl jasmonate induced a rapid depletion of ATP in both clones. In both clones, oligomycin (a mitochondrial ATP synthase inhibitor) did not increase ATP depletion induced by methyl jasmonate, whereas inhibition of glycolysis with 2-deoxyglucose did. High glucose levels protected both clones from methyl jasmonate-induced ATP depletion (and reduced methyl jasmonate-induced cytotoxicity), whereas high levels of pyruvate did not. These results suggest that methyl jasmonate induces ATP depletion mostly by compromising oxidative phosphorylation in the mitochondria. In conclusion, jasmonates can circumvent the resistance of mutant p53-expressing cells towards chemotherapy by inducing a nonapoptotic cell death. [ABSTRACT FROM AUTHOR]

Abstract: The B cell antigen receptor (BCR) composed of the ligand-binding membrane IgM (mIgM) and the signaling component, Ig-α/β, is known to inducibly associate with membrane microdomains rich in cholesterol and sphingolipids, termed lipid rafts. In this study we tested whether the Ig-α/β portion of the BCR has targeting information that allows it to be localized in lipid rafts. In order to do this, we cross-linked the Ig-α/β on the cell surface of the variant B cell line, WEHI 303.1.5, a derivative of the immature murine B cell line WEHI 231 that lacks μ heavy chain and expresses the Ig-α/β on the cell surface by itself. Using two methods to isolate detergent-insoluble, lipid raft-like fractions, we found that Ig-α/β without accompanying mIgM was constitutively located in these raft-like fractions and that the amount was marginally increased after Ig-α/β cross-linking. These results suggest that the Ig-α/β portion of the BCR has the ability to be compartmentalized into raft-like membrane domains even when not associated with mIgM and perhaps this targeting information is normally regulated by the presence of the mIgM portion of the receptor. [Copyright &y& Elsevier]

B-lymphoma cells express a highly tumor-specific antigen, monoclonal Ig, which is a promising target for immunotherapy. Previous work has demonstrated that B-lymphoma cells spontaneously process their endogenous monoclonal Ig and present variable (V) region peptides (Id-peptides) on their MHC class II molecules to CD4+ T cells. Id-specific CD4+ T cells protect mice against B-lymphoma cells in the absence of anti-idiotypic antibodies. The molecular mechanism by which Id-specific CD4+ T cells kill B-lymphoma cells is hitherto unknown. We here demonstrate in an Id-specific T-cell receptor (TCR)-transgenic mouse model that Id-specific CD4+ T cells induce apoptosis of Fas+ B-lymphoma cells in vitro by FasLigand (FasL)-Fas interaction. Moreover, the rare B lymphomas that had escaped rejection in TCR-transgenic mice had down-regulated their sensitivity to Fas-mediated apoptosis. Although these results suggest that FasL-Fas interaction is important, Id-specific CD4+ T cells could eliminate Id+ B-lymphoma cells in vivo by other mechanisms, since three independent ways of blocking FasL-Fas-mediated killing failed to abrogate tumor protection in TCR-transgenic mice. These results suggest that there are several redundant pathways by which Id-specific CD4+ T cells eliminate Id+ B-lymphoma cells in vivo, of which FasL-Fas interaction is only one. [ABSTRACT FROM AUTHOR]

Clearer evidence for immune surveillance in malignancy and the identification of many new tumour-associated antigens (TAAs) have driven novel vaccine and antibody-targeted responses for therapy in cancer. The exploitation of active immunisation may be particularly favourable for TAA where tolerance is incomplete but passive immunisation may offer an additional strategy where the immune repertoire is affected by either tolerance or immune suppression. This review will consider how to utilise both active and passive types of therapy delivered by T cells in the context of the failure of tumour-specific immunity by presenting cancer patients. This article will outline the progress, problems and prospects of several different vaccine and antibody-targeted approaches for immunotherapy of cancer where proof of principle pre-clinical studies have been or will soon be translated into the clinic. Two examples of vaccination-based therapies where both T cell- and antibody-mediated anti-tumour responses are likely to be relevant and two examples of oncofoetal antigen-specific antibody-directed T cell therapies are described in the following sections: (1) therapeutic vaccination against human papillomavirus (HPV) antigens in cervical neoplasia; (2) B cell lymphoma vaccines including against immunoglobulin idiotype; (3) oncofoetal antigens as tumour targets for redirecting T cells with antibody strategies. [Copyright &y& Elsevier]

Nonviral transposon piggyBac (PB) and lentiviral (LV) vectors have been used to deliver chimeric antigen receptor (CAR) to T cells. To understand the differences in the effects of PB and LV on CAR T-cell functions, a CAR targeting CD19 was cloned into PB and LV vectors, and the resulting pbCAR and lvCAR were delivered to T cells to generate CD19pbCAR and CD19lvCAR T cells. Both CD19CAR T-cell types were strongly cytotoxic and secreted high IFN-γ levels when incubated with Raji cells. TNF-α increased in CD19pbCAR T cells, whereas IL-10 increased in CD19lvCAR T cells. CD19pbCAR and CD19lvCAR T cells showed similar strong anti-tumor activity in Raji cell-induced mouse models, slightly reducing mouse weight while enhancing mouse survival. High, but not low or moderate, concentrations of CD19pbCAR T cells significantly inhibited Raji cell-induced tumor growth in vivo . These CD19pbCAR T cells were distributed mostly in mesenteric lymph nodes, bone marrow of the femur, spleen, kidneys, and lungs, specifically accumulating at CD19-rich sites and CD19-positive tumors, with CAR copy number being increased on day 7. These results indicate that pbCAR has its specific activities and functions in pbCAR T cells, making it a valuable tool for CAR T-cell immunotherapy., Competing Interests: All authors are employed by Shanghai Cell Therapy Group Corporation., (Copyright © 2022 Lin, Liu, Liu, Gao, Wang, Zhu, Rong, Cheng, Cai, Xu, Tan, Lv, Li, Sun and Qian.)

Active specific immunotherapy of neoplastic diseases is an elusive goal. Using a murine B lymphoma 2C3, we showed that vaccination with the killed tumor cells effectively induces protective immunity and a cytotoxic T cell (CTL) response. Similar protection, however, is rarely observed in mice bearing live tumor cells. These animals usually succumb to the progressively growing tumor. In this study, we inquired whether the splenic CTL induced during tumor progression in mice differ from those evoked by the killed tumor cells. Here we demonstrate that the CTL generated following vaccination are significantly different from those induced in the tumor-bearing hosts. Adding to the complexity, the CTL from the early tumor bearers also differ significantly from those induced at the late stages. These differences are based on their cytotoxic activity, MHC allele specificity, mitogen responsiveness, cytokine secretion profile and T cell receptor Vβ gene expression. The results clearly indicate that passive immunization with killed tumor is most effective, possibly because the CTL induced are not subject to the same regulatory pressure as those induced during active tumor growth. This decreasing effectiveness of CTL could be due to greater variability in antigenic stimulus, less involvement of innate immunity, changes in cytokine milieu and/or costimulatory factors. [ABSTRACT FROM AUTHOR]

We previously reported [Chakrabarti et al. (1992) Cell Immunol 142:54; 144:455] that, in a murine B lymphoma model 2C3, idiotype (Id)-specific CD8+ cytotoxic T lymphocytes (CTL) are generated in mice following hyperimmunization with irradiated tumor cells, and that they are effective in tumor rejection. The present study reveals that 2C3-specific CTL are also induced in spleens during tumor progression, but are not sustained. At the early stage of tumor growth, the splenic T cells following a 5-day incubation in vitro with killed 2C3 tumor targets, produce high levels of cytokines, namely interleukin-4 (IL-4), IL-10 and interferon γ (IFNγ). Their cytotoxic T lymphocyte (CTL) activity and cytokine levels, except IL-2, sharply decline at the late stage when the mice are increasingly moribund. Although the decline in cytokine level is also evident with CD4+ T cells, a precipitous and concurrent decrease occurs primarily in the IL-4 level with both CD4+ and CD8+ T cells of late-tumor-bearing animals (TBA). Study with the unseparated splenocytes also reveals that sevenfold less IL-4 is produced at the late stage. Furthermore, the cytotoxicity of CTL from late TBA can be effectively restored by addition of supernatants from the splenocyte culture of early TBA, or by IL-4, but not by IFNγ and IL-10. In addition, only IL-4-activated CD8+ T cells from the late TBA are found, by Winn assay, to be protective in vivo. Thus it appears that IL-4, required to sustain antitumor CTL activity, is consumed by T and possibly other cells at the late stage of tumor growth, thereby compromising host immunity against the tumor. We contend that induction or maintenance of protective immunity depends not only on the tumor antigen but also on the specific cytokine milieu in a tumor-bearing host. [ABSTRACT FROM AUTHOR]

We report the case of an 83-year-old woman admitted to the accident and emergency unit for pneumopathy. The blood cell count on the DXH automaton (Coulter® ™ UniCel® DxH) found a normochromic and normocytic anemia, anormal platelet count and subnormal leukocyte formula. The only alarm raised by the automaton was the presence of a basocytosis. A control of the leucocyte count by flow cytometry and blood smear has been done. It revealed there was no basocytosis, but showed the presence of an atypical monomorphic lymphocytes B population (T/B < 1 ratio in flow cytometry), around which platelets aggregated. The lymphocytic immunophenotyping allowed us to highlight the presence of a CD5+ B clonal subpopulation.

High plasma lactate is associated with poor prognosis of many malignancies, but its role in virally mediated cancer progression and underlying molecular mechanisms are unclear. Epstein-Barr virus (EBV), the first human oncogenic virus, causes several cancers, including B-cell lymphoma. Here, we report that lactate dehydrogenase A (LDH-A) expression and lactate production are elevated in EBV-immortalized B lymphoblastic cells, and lactic acid (LA; acidic lactate) at low concentration triggers EBV-infected B-cell adhesion, morphological changes, and proliferation in vitro and in vivo Moreover, LA-induced responses of EBV-infected B cells uniquely occurs in viral latency type III, and it is dramatically associated with the inhibition of global viral microRNAs, particularly the miR-BHRF1 cluster, and the high expression of SMAD3 , JUN , and COL1A genes. The introduction of miR-BHRF1-1 blocks the LA-induced effects of EBV-infected B cells. Thus, this may be a novel mechanism to explain EBV-immortalized B lymphoblastic cell malignancy in an LA microenvironment. IMPORTANCE The tumor microenvironment is complicated, and lactate, which is created by cell metabolism, contributes to an acidic microenvironment that facilitates cancer progression. However, how LA operates in virus-associated cancers is unclear. Thus, we studied how EBV (the first tumor virus identified in humans; it is associated with many cancers) upregulates the expression of LDH-A and lactate production in B lymphoma cells. Elevated LA induces adhesion and the growth of EBV-infected B cells by inhibiting viral microRNA transcription. Thus, we offer a novel understanding of how EBV utilizes an acidic microenvironment to promote cancer development., (Copyright © 2018 American Society for Microbiology.)

B cell neoplasms comprise >50% of blood cancers. However, many types of B cell malignancies remain incurable. Identification and validation of novel genetic risk factors and oncogenic signaling pathways are imperative for the development of new therapeutic strategies. We and others recently identified TRAF3, a cytoplasmic adaptor protein, as a novel tumor suppressor in B lymphocytes. We found that TRAF3 inactivation results in prolonged survival of mature B cells, which eventually leads to spontaneous development of B lymphomas in mice. Corroborating our findings, TRAF3 deletions and inactivating mutations frequently occur in human B cell chronic lymphocytic leukemia, splenic marginal zone lymphoma, mantle cell lymphoma, multiple myeloma, Waldenström's macroglobulinemia, and Hodgkin lymphoma. In this context, we have been investigating TRAF3 signaling mechanisms in B cells, and are developing new therapeutic strategies to target TRAF3 downstream signaling pathways in B cell neoplasms. Here we discuss our new translational data that demonstrate the therapeutic potential of targeting TRAF3 downstream signaling pathways in B lymphoma and multiple myeloma.