PAX5 functions as a tumor suppressor by RB-E2F-mediated cell cycle arrest in Kaposi sarcoma-associated herpesvirus-infected primary effusion lymphoma.

Primary effusion lymphoma (PEL) is a malignant B-cell lymphoma attributable to Kaposi sarcoma-associated herpesvirus (KSHV) infection. PEL is characterized by invasive behavior, showing recurrent effusions in body cavities. The clinical outcome and typical prognosis in patients with PEL are poor and potentially lethal. Clarification of the pathogenesis in PEL is urgently needed in order to develop novel therapies. PEL cells generally lack B-cell surface markers, and we therefore hypothesized that the B-cell transcription factor, PAX5, would be down-regulated in PEL. The expression of PAX5 is detected from the pro-B to the mature B-cell stage and is indispensable for the differentiation of B-cells. PAX5 was silenced in PEL cells via its promoter methylation. Up-regulation of PAX5 induced several genes coding for B-cell surface marker mRNA, but not protein level. PAX5 inhibited cell growth via G1 cell cycle arrest. PAX5 bound to RB and increased its protein expression. RB/E2F-regulated genes were significantly down-regulated in microarray analysis and PCR experiments. To elucidate the in vivo role of PAX5, we examined the restoration of PAX5 in a PEL mouse model. The ascites volume and organ invasions were significantly suppressed by PAX5 restoration. Reduction of PAX5 has played a crucial role in the oncogenesis of PEL, and PAX5 is a tumor suppressor in PEL. Targeting PAX5 could represent a novel therapeutic strategy for patients with PEL.

Pediatric Erythroid Sarcoma Diagnostically Confirmed by Identification of a Recurrent NFIA::CBFA2T3 Fusion.

Erythroid sarcoma (ES) is exceedingly rare in the pediatric population with only a handful of reports of de novo cases, mostly occurring in the central nervous system (CNS) or orbit. It is clinically and pathologically challenging and can masquerade as a nonhematopoietic small round blue cell tumor. Clinical presentation of ES without bone marrow involvement makes diagnosis particularly difficult. We describe a 22-month-old female with ES who presented with a 2-cm mass involving the left parotid region and CNS. The presence of crush/fixation artifact from the initial biopsy made definitive classification of this highly proliferative and malignant neoplasm challenging despite an extensive immunohistochemical workup. Molecular studies including RNA-sequencing revealed a NFIA::CBFA2T3 fusion. This fusion has been identified in several cases of de novo acute erythroid leukemia (AEL) and gene expression analysis comparing this case to other AELs revealed a similar transcriptional profile. Given the diagnostically challenging nature of this tumor, clinical RNA-sequencing was essential for establishing a diagnosis.

Molecular Features of HHV8 Monoclonal Microlymphoma Associated with Kaposi Sarcoma and Multicentric Castleman Disease in an HIV-Negative Patient.

Human herpesvirus 8 (HHV8)-associated diseases include Kaposi sarcoma (KS), multicentric Castleman disease (MCD), germinotropic lymphoproliferative disorder (GLPD), Kaposi sarcoma inflammatory cytokine syndrome (KICS), HHV8-positive diffuse large B-cell lymphoma (HHV8+ DLBCL), primary effusion lymphoma (PEL), and extra-cavitary PEL (ECPEL). We report the case of a human immunodeficiency virus (HIV)-negative male treated for cutaneous KS, who developed generalized lymphadenopathy, hepatosplenomegaly, pleural and abdominal effusions, renal insufficiency, and pancytopenia. The excised lymph node showed features of concomitant involvement by micro-KS and MCD, with aggregates of HHV8+, Epstein Barr virus (EBV)-negative, IgM+, and lambda+ plasmablasts reminiscent of microlymphoma. Molecular investigations revealed a somatically hypermutated (SHM) monoclonal rearrangement of the immunoglobulin heavy chain (IGH), accounting for 4% of the B-cell population of the lymph node. Mutational analyses identified a pathogenic variant of KMT2D and variants of unknown significance in KMT2D, FOXO1, ARID1A, and KMT2A. The patient died shortly after surgery. The histological features (HHV8+, EBV-, IgM+, Lambda+, MCD+), integrated with the molecular findings (monoclonal IGH, SHM+, KMT2D mutated), supported the diagnosis of a monoclonal HHV8+ microlymphoma, with features intermediate between an incipient HHV8+ DLBCL and an EBV-negative ECPEL highlighting the challenges in the accurate classification of HHV8-driven lymphoid proliferations.

5-AZA Upregulates SOCS3 and PTPN6/SHP1, Inhibiting STAT3 and Potentiating the Effects of AG490 against Primary Effusion Lymphoma Cells.

Epigenetic modifications, including aberrant DNA methylation occurring at the promoters of oncogenes and oncosuppressor genes and histone modifications, can contribute to carcinogenesis. Aberrant methylation mediated by histone methylatransferases, alongside histones, can affect methylation of proteins involved in the regulation of pro-survival pathways such as JAK/STAT and contribute to their activation. In this study, we used DNA or histone demethylating agents, 5-Azacytidine (5-AZA) or DS-3201 (valemetostat), respectively, to treat primary effusion lymphoma (PEL) cells, alone or in combination with AG490, a Signal transducer and activator of transcription 3 (STAT3) inhibitor. Cell viability was investigated by trypan blue assay and FACS analysis. The molecular changes induced by 5-AZA and/or AG490 treatments were investigated by Western blot analysis, while cytokine release by PEL cells treated by these drugs was evaluated by Luminex. Statistical analyses were performed with Graphpad Prism® software (version 9) and analyzed by Student's t test or a nonparametric one-way ANOVA test. The results obtained in this study suggest that 5-AZA upregulated molecules that inhibit STAT3 tyrosine phosphorylation, namely Suppressor of Cytokine Signaling 3 (SOCS3) and tyrosine-protein phosphatase non-receptor type (PTPN) 6/Src homology region 2 domain-containing phosphatase-1 (SHP-1), reducing STAT3 activation and downregulating several STAT3 pro-survival targets in PEL cells. As this lymphoma is highly dependent on the constitutive activation of STAT3, 5-AZA impaired PEL cell survival, and when used in combination with AG490 JAK2/STAT3 inhibitor, it potentiated its cytotoxic effect. Differently from 5-AZA, the inhibition of the EZH1/2 histone methyltransferase by DS-3201, reported to contribute to STAT3 activation in other cancers, slightly affected STAT3 phosphorylation or survival in PEL cells, either alone or in combination with AG490. This study suggests that 5-AZA, by upregulating the expression level of SOCS3 and PTPN6/SHP1, reduced STAT3 activation and improved the outcome of treatment targeting this transcription factor in PEL cells.

Prevalence and factors associated with the perception of perineal laceration: a cross-sectional study with data from the Nascer no Brasil Survey, 2011 and 2012 / Prevalencia y factores asociados a la percepción de laceración perineal: estudio transversal con datos de la Encuesta Nascer no Brasil, 2011 y 2012 / Prevalência e fatores associados à percepção da laceração perineal: estudo transversal com dados do Inquérito Nascer no Brasil, 2011 e 2012

Abstract Objective: To describe the prevalence of perineal laceration, based on the self-reported perception of postpartum women, and to analyze factors associated with its occurrence in Brazil. Methods: This was a cross-sectional study conducted with 23,894 postpartum women, excluding twin pregnancies, cesarean sections, and births with episiotomies, between 2011 and 2012. Prevalence ratios (PR) and 95% confidence intervals (95%CI) of association between the event and maternal, fetus/newborn, obstetric and clinical management characteristics were estimated in hierarchical Poisson regression models. Results: Out of 4,606 postpartum women, 49.5% (95%CI 46.1;42.9) self-reported perineal laceration. Being an adolescent (PR = 1.12; 95%CI 1.02;1.25), primipara (PR = 1.47; 95%CI 1.33;1.63), having had excessive gestational weight gain (PR = 1.17; 95%CI 1.07;1.29) and having undergone the Kristeller maneuver (PR = 1.18; 95%CI 1.08;1.29) increased the proportion of the outcome. Conclusion: The results found call for prenatal care and adjustments to childbirth care so as to be in accordance with current recommendations.

Resumen Objetivo: Describir la prevalencia de laceración perineal, a partir de la percepción autoinformada de puérperas, y analizar los factores asociados a su aparición en Brasil. Métodos: Estudio transversal entre 2011 y 2012, con 23.894 puérperas, excluyendo embarazos gemelares, cesáreas y partos con episiotomías. Se estimaron razones de prevalencia (RP) e intervalos de confianza del 95% (IC95%) de la asociación entre el evento y las características maternas, feto/recién nacido, obstétricas y de manejo clínico en modelos de regresión jerárquica de Poisson. Resultados: Entre 4.606 mujeres en posparto, el 49,5%(IC95%:46,1;42,9) informó laceración perineal. Ser adolescente (RP = 1,12; IC95% 1,02;1,25), primipara (RP = 1,47; IC95% 1,33;1,63), haber tenido aumento excesivo de peso gestacional (RP = 1,17; IC95% 1,07;1,29) y haber sido sometido a la maniobra de Kristeller (RP = 1,18; IC95% 1,08;1,29) aumentó la proporción de resultados. Conclusión: Los resultados encontrados requieren atención prenatal y ajustes en la atención del parto de acuerdo con las recomendaciones actuales.

Resumo Objetivo: Descrever a prevalência da laceração perineal segundo a percepção autorrelatada da puérpera, e analisar os fatores associados à sua ocorrência no Brasil. Métodos: Estudo transversal conduzido em 23.894 puérperas, excluindo-se gestações gemelares, cesarianas e partos com episiotomias entre 2011 e 2012. Razões de prevalência (RP) e intervalos de confiança de 95% (IC95%) da associação entre o evento e as características maternas, feto/recém-nato, obstétricas e manejo clínico foram estimadas em modelos de regressão de Poisson hierarquizados. Resultados: Entre 4.606 puérperas, 49,5% (IC95% 46,1;42,9) autorrelataram laceração perineal. Ser adolescente (RP = 1,12; IC95% 1,02;1,25), primípara (RP = 1,47; IC95% 1,33;1,63), ter tido ganho de peso gestacional excessivo (RP = 1,17; IC95% 1,07;1,29) e ter sido submetida à manobra de Kristeller (RP = 1,18; IC95% 1,08;1,29) elevaram a proporção do desfecho. Conclusão: Os resultados encontrados demandam atenção pré-natal e adequações na assistência ao parto conforme recomendações vigentes.

HSP110 Inhibition in Primary Effusion Lymphoma Cells: One Molecule, Many Pro-Survival Targets.

Heat shock proteins (HSPs) are highly expressed in cancer cells and represent a promising target in anti-cancer therapy. In this study, we investigated for the first time the expression of high-molecular-weight HSP110, belonging to the HSP70 family of proteins, in Primary Effusion Lymphoma (PEL) and explored its role in their survival. This is a rare lymphoma associated with KSHV, for which an effective therapy remains to be discovered. The results obtained from this study suggest that targeting HSP110 could be a very promising strategy against PEL, as its silencing induced lysosomal membrane permeabilization, the cleavage of BID, caspase 8 activation, downregulated c-Myc, and strongly impaired the HR and NHEJ DNA repair pathways, leading to apoptotic cell death. Since chemical inhibitors of this HSP are not commercially available yet, this study encourages a more intense search in this direction in order to discover a new potential treatment that is effective against this and likely other B cell lymphomas that are known to overexpress HSP110.

Modulation of Epstein-Barr-Virus (EBV)-Associated Cancers by Co-Infections.

The oncogenic and persistent Epstein Barr virus (EBV) is carried by more than 95% of the human adult population. While asymptomatic in most of these, EBV can cause a wide variety of malignancies of lymphoid or epithelial cell origin. Some of these are also associated with co-infections that either increase EBV-induced tumorigenesis or weaken its immune control. The respective pathogens include Kaposi-sarcoma-associated herpesvirus (KSHV), Plasmodium falciparum and human immunodeficiency virus (HIV). In this review, I will discuss the respective tumor entities and possible mechanisms by which co-infections increase the EBV-associated cancer burden. A better understanding of the underlying mechanisms could allow us to identify crucial features of EBV-associated malignancies and defects in their immune control. These could then be explored to develop therapies against the respective cancers by targeting EBV and/or the respective co-infections with pathogen-specific therapies or vaccinations.

Clinical management of Kaposi sarcoma herpesvirus-associated diseases: an update on disease manifestations and treatment strategies.

INTRODUCTION: Kaposi sarcoma herpes virus (KSHV) is associated with several diseases including Kaposi sarcoma, a form of multicentric Castleman's disease, primary effusion lymphoma, and an inflammatory cytokine syndrome. These KSHV-associated diseases (KAD) can present with heterogenous signs and symptoms that are often associated with cytokine dysregulation that may result in multiorgan dysfunction. The inability to promptly diagnose and treat these conditions can result in long-term complications and mortality. AREAS COVERED: Existing epidemiological subtypes of existing KSHV-associated diseases, specifically Kaposi sarcoma as well as the incidence of several KSHV-associated disorders are described. We review the KSHV latent and lytic phases as they correlate with KSHV-associated diseases. Given the complicated presentations, we discuss the clinical manifestations, current diagnostic criteria, existing treatment algorithms for individual KAD, and when they occur concurrently. With emerging evidence on the virus and host interactions, we evaluate novel approaches for the treatment of KAD. An extensive literature search was conducted to support these findings. EXPERT OPINION: KSHV leads to complex and concurrent disease processes that are often underdiagnosed both in the United States and worldwide. New therapies that exist for many of these conditions focus on chemotherapy-sparing options that seek to target the underlying viral pathogenesis or immunotherapy strategies.

NFE2L2 and STAT3 Converge on Common Targets to Promote Survival of Primary Lymphoma Cells.

NFE2L2 and STAT3 are key pro-survival molecules, and thus, their targeting may represent a promising anti-cancer strategy. In this study, we found that a positive feedback loop occurred between them and provided evidence that their concomitant inhibition efficiently impaired the survival of PEL cells, a rare, aggressive B cell lymphoma associated with the gammaherpesvirus KSHV and often also EBV. At the molecular level, we found that NFE2L2 and STAT3 converged in the regulation of several pro-survival molecules and in the activation of processes essential for the adaption of lymphoma cells to stress. Among those, STAT3 and NFE2L2 promoted the activation of pathways such as MAPK3/1 and MTOR that positively regulate protein synthesis, sustained the antioxidant response, expression of molecules such as MYC, BIRC5, CCND1, and HSP, and allowed DDR execution. The findings of this study suggest that the concomitant inhibition of NFE2L2 and STAT3 may be considered a therapeutic option for the treatment of this lymphoma that poorly responds to chemotherapies.

Primary Effusion Lymphoma, Multicentric Castleman's Disease, and Kaposi's Sarcoma in an HHV-8 and HIV-Positive Patient: A Case Report.

Primary effusion lymphoma (PEL), Kaposi's sarcoma (KS), and multicentric Castleman's disease (MCD) is an uncommon group of diseases included in the same spectrum with related characteristics. The coexistence of all of them in the same individual is a rare occurrence. We present the case of a 25-year-old patient diagnosed with human immunodeficiency virus (HIV) and the development of all these related pathologies. Despite the use of intensive treatment according to the latest recommendations, the evolution was unfavorable. This case reflects the need for new therapies and research in this field.

HHV8 and EBV-negative primary effusion-based lymphoma: A case report of a new provisional entity and review of literature.

Key Clinical Message: HHV8- and EBV-negative primary effusion lymphoma is an extremely rare neoplasm involving body cavities without detectable tumor mass. It usually presents in elderly patients without known immunodeficiency. Compared to primary effusion lymphoma, it has a better prognosis.Primary effusion lymphoma (PEL) is a rare non-Hodgkin lymphoma confined exclusively to body cavities without detectable tumor masses. The term PEL-like is an entity similar to PEL in clinical presentation but without relation to human herpesvirus 8 (HHV8). We report a case of HHV8- and EBV-negative primary effusion-based lymphoma.

HHV8-unrelated primary effusion lymphoma in a patient with HBV-related liver cirrhosis: A case successfully treated with rituximab and lenalidomide.

Human herpesvirus type 8 (HHV-8) unrelated primary effusion lymphoma (PEL) like lymphoma (PEL-LL) is an exceedingly rare non-Hodgkin lymphoma with no characteristic symptoms and consensus on the optimal treatment. This case report presents a 55-year-old man with prior HBV-related Child-Pugh B liver cirrhosis and developing activity-related dyspnea. A moderate amount of pleural effusion was identified without tumor masses, and cytological studies confirmed a diagnosis of PEL-LL. The patient received rituximab and lenalidomide, albeit with HBV infection, and is currently on maintenance therapy with resolving symptoms but without HBV reactivation. Hence, the R2 protocol (rituximab and lenalidomide) might be clinically effective and safe for PEL-LL patients with HBV infection and Child-Pugh B liver cirrhosis.

Nigericin Induces Apoptosis in Primary Effusion Lymphoma Cells by Mitochondrial Membrane Hyperpolarization and ß-Catenin Destabilization.

BACKGROUND/AIM: Primary effusion lymphoma (PEL) is classified as a rare non-Hodgkin's B-cell lymphoma that is caused by Kaposi's sarcoma-associated herpesvirus (KSHV); PEL cells are latently infected with KSHV. PEL is frequently resistant to conventional chemotherapies. Therefore, the development of novel therapeutic agents is urgently required. Nigericin, a H+ and K+ ionophore, possesses unique pharmacological effects. However, the effects of nigericin on PEL cells remain unknown. MATERIALS AND METHODS: We examined the cytotoxic effects of the K+ ionophores, nigericin, nonactin, and valinomycin, on various B-lymphoma cells including PEL. We also evaluated ionophore-induced changes in signaling pathways involved in KSHV-induced oncogenesis. Moreover, the effects of nigericin on mitochondrial membrane potential and viral reactivation in PEL were analyzed. RESULTS: Although the three tested ionophores inhibited the proliferation of several B-lymphoma cell lines, nigericin inhibited the proliferation of PEL cells compared to KSHV-negative cells. In PEL cells, nigericin disrupted the mitochondrial membrane potential and caused the release of cytochrome c, which triggered caspase-9-mediated apoptosis. Nigericin also induced both an increase in phosphorylated p38 MAPK and proteasomal degradation of ß-catenin. Combination treatment of nigericin with the p38 MAPK inhibitor SB203580 potentiated the cytotoxic effects towards PEL cells, compared to either compound alone. Meanwhile, nigericin did not influence viral replication in PEL cells. CONCLUSION: Nigericin induces apoptosis in PEL cells by mitochondrial dysfunction and down-regulation of Wnt/ß-catenin signaling. Thus, nigericin is a novel drug candidate for treating PEL without the risk of de novo KSHV infection.

Time-lapse between periodontal regeneration surgery and root canal therapy in sever combined periodontal-endodontic lesions.

Objective: The purpose of this study was to evaluate the time-lapse of periodontal regeneration surgery of combined periodontal-endodontic lesions (PEL) after root canal therapy (RCT) to guide the clinical treatment. Methods: 26 patients (28 teeth) with severe combined PEL were equally divided into 4 groups (n = 7); the control group included patients who underwent periodontal regeneration surgery with no prior RCT and the remaining three experimental groups including patients who received periodontal regeneration surgery post-RCT either immediately or after 3 and 6 months. The probing depth, clinical attachment loss, and periodontal bone density were measured before or after 3, 6, and 12 months post-RCT, respectively. Results: Periodontal regeneration surgery could improve the PD (Probing Depth), CAL (Clinical Attachment Loss), BD (Bone Mineral Density) values irrespective of whether the RCT was performed within 12 months or not. However, obviously improved PD, CAL and BD were observed when surgery was performed post-RCT. The time lapse between RCT and periodontal regeneration surgery had no obvious effects on the periodontal index in 3 months after the surgery. Moreover, these periodontal indexes tend to stabilize in 3 to 6 months after the surgery with no significant differences. Conclusion: Although there were no obvious impacts of time lapse between RCT and periodontal regeneration surgery on the severe PEL, an earlier periodontal surgery might contribute to the healing of periodontal lesions.

HSPs/STAT3 Interplay Sustains DDR and Promotes Cytokine Release by Primary Effusion Lymphoma Cells.

Primary effusion lymphoma (PEL) is a rare and aggressive B-cell lymphoma, against which current therapies usually fail. In the present study, we show that targeting HSPs, such as HSP27, HSP70 and HSP90, could be an efficient strategy to reduce PEL cell survival, as it induces strong DNA damage, which correlated with an impairment of DDR. Moreover, as HSP27, HSP70 and HSP90 cross talk with STAT3, their inhibition results in STAT3 de-phosphorylation and. On the other hand, the inhibition of STAT3 may downregulate these HSPs. These findings suggest that targeting HSPs has important implications in cancer therapy, as it can reduce the release of cytokines by PEL cells, which, besides affecting their own survival, could negatively influence anti-cancer immune response.

Daratumumab induces cell-mediated cytotoxicity of primary effusion lymphoma and is active against refractory disease.

Primary effusion lymphoma (PEL), an aggressive non-Hodgkin lymphoma caused by Kaposi sarcoma-associated herpesvirus (KSHV), lacks standard therapy and has a median survival of 10-22 months with combination chemotherapy. PEL is a tumor of plasmablast-like B cells generally expressing CD38, the target of daratumumab (Dara). Initially, we assessed PEL cells from eight patients and established that each expressed high levels of CD38 by flow cytometry. PEL cell lines were also evaluated and most had high CD38 expression. We then assessed Dara's effects on complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC) of PEL cell lines as well as its clinical benefits on two patients with PEL. Despite high CD38 expression, Dara did not induce CDC of PEL cell lines, due in part to high levels of the complement-inhibitory proteins, CD55 and CD59. However, Dara induced significant and dose-dependent increases in ADCC, particularly in those lines with high CD38 levels. Two FDA-approved drugs, all trans-retinoic acid (ATRA) and pomalidomide (Pom), significantly increased surface CD38 levels in low-CD38 expressing PEL cell lines, resulting in increased Dara-induced ADCC. Two patients with refractory PEL were treated with Dara alone or in combination with Pom. One patient with leptomeningeal PEL had a complete response to Dara and Pom combination treatment. Others had improvement in performance status and resolution of malignant ascites with Dara alone. Together, these data support the use of Dara monotherapy or in combination with ATRA or Pom as a potential therapeutic option for PEL.

A rare case of fluid overload-associated large B-cell lymphoma and antigen loss at relapse.

Fluid overload-associated large B-cell lymphoma (FO-LBCL) is a new addition to the list of large B-cell lymphomas in the 5th edition of the World Health Organization Classification of Haematolymphoid Tumours (WHO-HAEM5). This report presents an unusual case of FO-LBCL with partial B cell antigen loss at relapse and reviews the characteristics, treatment, and prognosis of these patients to enhance our understanding of this disease. Immunophenotyping was performed through immunohistochemistry and flow cytometry. Immunoglobulin gene rearrangements were analyzed using BIOMED-2 multiplex primers. MYC, BCL2, and BCL6 gene rearrangements were detected by fluorescent in situ hybridization (FISH). Cell-free DNA (cfDNA) from pleural effusion and peripheral blood was subjected to somatic mutation evaluation using next-generation sequencing (NGS). In 2020, the patient was initially diagnosed with tuberculous pleurisy and received anti-tuberculous drugs. Subsequent testing of the pleural effusion cell block revealed that the large cells to be positive for CD10, CD20, CD79a, PAX5, MUM1, Bcl-2, Bcl-6, and c-myc and negative for CD3, CD30, Cyclin D1, and HHV8. In situ hybridization for Epstein-Barr virus (EBV)-associated mRNA (EBER-ISH) was negative. Additionally, a clonal rearrangement of immunoglobulin heavy locus (IGH) FR2-JH was detected; the results of MYC, BCL2, and BCL6 gene rearrangements were all negative. Following pleural drainage treatment, the patient achieved symptom remission and was diagnosed with large B-cell lymphoma (HHV8-unrelated PEL-like lymphoma). In 2022, the patient was readmitted due to the recurrence of pleural effusion. The pleural effusion cell block revealed a distinct immunophenotype compared to previous findings, positivity for PAX5 and negativity for CD20, CD10, CD3, CD5, CD30, CD38, CD138, CD79a, MUM1, Bcl-2, Bcl-6, Cyclin D1, c-myc, ALK, and HHV8. Identical IGH FR2-JH clonal rearrangement suggested the recurrence of the original clone. CfDNA analysis showed mutations in CD79B, MYD88, CCND3, and DTX1. The patient was ultimately diagnosed with FO-LBCL based on the WHO-HAEM5 classification. Diagnosis of FO-LBCL should be differentiated from primary effusion lymphoma (PEL). The features of this case align with the description of "FO-LBCL" in WHO-HAEM5 and "HHV8 and EBV-negative primary effusion-based lymphoma" in International Consensus Classification (ICC). FO-LBCL patients generally have a more favorable prognosis compared to PEL. In this case, the patient exhibited a favorable prognosis for over 22 months without additional treatment apart from pleural drainage.

Activation of IL1 signaling molecules by Kaposi's sarcoma-associated herpesvirus.

Objective: Kaposi's Sarcoma-associated Herpesvirus (KSHV) is the etiologic agent of several human cancers, including Kaposi's sarcoma (KS) and Primary effusion lymphoma (PEL), which are usually seen in immunocompromised patients while lack of effective therapeutic options. Interleukin1 (IL1) family is a major mediator for inflammation response and has functional role in both innate and adaptive immunity. In contrast to the well-studied IL1 molecules, the activation and functional role of IL1 receptor/co-receptor and other related ligands, such as the IL1 receptor accessory protein (IL1RAP), in KSHV pathogenesis and tumorigenesis remain almost unknown. Methods: In the current study, a series of KSHV negative and positive primary or tumor cells, as well as AIDS-KS tumor samples from cohort HIV+ patients were used to compare and determine the activation status of IL1 signaling molecules, and their functional roles in KSHV pathogenesis. Results: We reported the high activation of multiple IL1 signaling molecules, including IL1, IL36, IL1R1, IL1RAP and IRAKs, during KSHV latent and lytic stages, as well as in clinical samples from patients with KSHV-related malignancies. Directly targeting these molecules especially IL1R1 and IL1RAP significantly impaired the survival and growth of KSHV+ tumor cells, as well as their colony formation on 3-D culture. Conclusion: Our data indicate the importance of IL1 signaling molecules in KSHV pathogenesis and tumorigenesis, which may represent attractive therapeutic targets against these virus-associated diseases.

Nm23-H1 induces apoptosis in primary effusion lymphoma cells via inhibition of NF-κB signaling through interaction with oncogenic latent protein vFLIP K13 of Kaposi's sarcoma-associated herpes virus.

BACKGROUND: Primary effusion lymphoma (PEL) is an aggressive form of non-Hodgkin lymphoma of B cells caused by Kaposi's Sarcoma-associated Herpes Virus (KSHV). KSHV encoded latent and lytic antigens promote oncogenic transformation and evade apoptosis through the modulation of various host cellular signaling pathways. Nm23-H1 is a known metastatic suppressor whose expression inversely correlates with the metastatic potential of different cancers. Here, we set out to assess the role of Nm23-H1 in PEL development. METHODS: Flow cytometry and real-time PCR assays were performed for Nm23-H1 expression analysis. Induction of apoptosis was assessed using Western blotting and flow cytometry-based assays in Nm23-H1 overexpressing cells. Co-immunoprecipitation assays, confocal microscopy and imaging flow cytometry were performed to determine Nm23-H1 and vFLIP K13 protein-protein interaction. A PEL cell-induced xenograft model was established in non-obese diabetic/severely combined immunodeficient (NOD/SCID) mice to validate the effect of Nm23-H1 overexpression. RESULTS: We found that Nm23-H1 expression was significantly downregulated both at transcriptional and protein levels in PEL cell lines and that its overexpression triggered mitochondrial-mediated caspase-dependent apoptosis. We revealed Nm23-H1 interacts with the latent protein vFLIP K13 and that Nm23-H1 overexpression leads to inhibition of vFLIP K13 driven nuclear factor-kappa B (NF-κB) signaling with concurrent inhibition of autocrine and paracrine growth factors and downregulation of latent KSHV antigens without induction of active lytic reactivation. We also confirmed the effects of Nm23-H1 overexpression in a PEL cell-induced xenograft model in NOD/SCID mice. CONCLUSION: Downregulation of Nm23-H1 expression in KSHV-infected PEL cells and its overexpression trigger apoptosis by impairing vFLIP K13-driven NF-κB signaling, suggesting therapeutic implications of Nm23-H1 for primary effusion lymphomas.

SUMO Modification of Histone Demethylase KDM4A in Kaposi's Sarcoma-Associated Herpesvirus-Induced Primary Effusion Lymphoma.

Primary effusion lymphoma (PEL) is a fatal B-cell lymphoma caused by Kaposi's sarcoma-associated herpesvirus (KSHV) infection. Inducing KSHV lytic replication that causes the death of host cells is an attractive treatment approach for PE; however, combination therapy inhibiting viral production is frequently needed to improve its outcomes. We have previously shown that the KSHV lytic protein K-bZIP can SUMOylate histone lysine demethylase 4A (KDM4A) at lysine 471 (K471) and this SUMOylation is required for virus production upon KSHV reactivation. Here, we demonstrate that SUMOylation of KDM4A orchestrates PEL cell survival, a major challenge for the success of PEL treatment; and cell movement and angiogenesis, the cell functions contributing to PEL cell extravasation and dissemination. Furthermore, integrated ChIP-seq and RNA-seq analyses identified interleukin-10 (IL-10), an immunosuppressive cytokine, as a novel downstream target of KDM4A. We demonstrate that PEL-induced angiogenesis is dependent on IL-10. More importantly, single-cell RNA sequencing (scRNA-seq) analysis demonstrated that, at the late stage of KSHV reactivation, KDM4A determines the fates of PEL cells, as evidenced by two distinct cell populations; one with less apoptotic signaling expresses high levels of viral genes and the other is exactly opposite, while KDM4A-K417R-expressing cells contain only the apoptotic population with less viral gene expression. Consistently, KDM4A knockout significantly reduced cell viability and virus production in KSHV-reactivated PEL cells. Since inhibiting PEL extravasation and eradicating KSHV-infected PEL cells without increasing viral load provide a strong rationale for treating PEL, this study indicates targeting KDM4A as a promising therapeutic option for treating PEL. IMPORTANCE PEL is an aggressive and untreatable B-cell lymphoma caused by KSHV infection. Therefore, new therapeutic approaches for PEL need to be investigated. Since simultaneous induction of KSHV reactivation and apoptosis can directly kill PEL cells, they have been applied in the treatment of this hematologic malignancy and have made progress. Epigenetic therapy with histone deacetylase (HDAC) inhibitors has been proved to treat PEL. However, the antitumor efficacies of HDAC inhibitors are modest and new approaches are needed. Following our previous report showing that the histone lysine demethylase KDM4A and its SUMOylation are required for lytic reactivation of KSHV in PEL cells, we further investigated its cellular function. Here, we found that SUMOylation of KDM4A is required for the survival, movement, and angiogenesis of lytic KSHV-infected PEL cells. Together with our previous finding showing the importance of KDM4A SUMOylation in viral production, KDM4A can be a potential therapeutic target for PEL.