Lenalidomide, Thalidomide, and Pomalidomide Reactivate the Epstein-Barr Virus Lytic Cycle through Phosphoinositide 3-Kinase Signaling and Ikaros Expression

Genetic and immunological features of immune deficiency and dysregulation-associated lymphoproliferations and lymphomas as a basis for classification

Immune deficiency and dysregulation-associated lymphoproliferative disorders and lymphomas (IDD-LPDs) encompass a heterogeneous clinical and pathological spectrum of disorders that range from indolent lymphoproliferations to aggressive lymphomas. They arise in a variety of clinical settings and are associated with oncogenic viruses such as the Epstein-Barr virus (EBV) and Kaposi sarcoma-associated herpesvirus/human herpes virus (KSHV/HHV8) in some, but not all, cases. The recognition of IDD-LPDs as distinct from LPDs in immune competent patients is essential to tailor clinical management options for affected patients. The 5th edition of the World Health Organisation classification has introduced an integrated classification of IDD-LPDs with the goal of standardising diagnoses among different settings to enhance clinical decision support. In parallel, new knowledge in the field, particularly surrounding the role of oncogenic viruses and the tumour microenvironment, has led to clearer understanding of the complex pathogenesis of IDD-LPDs and how these features can be precisely harnessed for therapeutic purposes. In this perspective, we highlight the need for multidisciplinary decision-making to augment patient care as well as key areas where evolving concepts offer challenges and opportunities for clinical management, research and future iterations of the classification.

Single-cell transcriptional profile of CD34+ hematopoietic progenitor cells from del(5q) myelodysplastic syndromes and impact of lenalidomide

While myelodysplastic syndromes with del(5q) (del(5q) MDS) comprises a well-defined hematological subgroup, the molecular basis underlying its origin remains unknown. Using single cell RNA-seq (scRNA-seq) on CD34+ progenitors from del(5q) MDS patients, we have identified cells harboring the deletion, characterizing the transcriptional impact of this genetic insult on disease pathogenesis and treatment response. Interestingly, both del(5q) and non-del(5q) cells present similar transcriptional lesions, indicating that all cells, and not only those harboring the deletion, may contribute to aberrant hematopoietic differentiation. However, gene regulatory network (GRN) analyses reveal a group of regulons showing aberrant activity that could trigger altered hematopoiesis exclusively in del(5q) cells, pointing to a more prominent role of these cells in disease phenotype. In del(5q) MDS patients achieving hematological response upon lenalidomide treatment, the drug reverts several transcriptional alterations in both del(5q) and non-del(5q) cells, but other lesions remain, which may be responsible for potential future relapses. Moreover, lack of hematological response is associated with the inability of lenalidomide to reverse transcriptional alterations. Collectively, this study reveals transcriptional alterations that could contribute to the pathogenesis and treatment response of del(5q) MDS.

Epstein-Barr Virus Driven Hodgkin's Lymphoma after a Short Course of Daratumumab Treatment for Relapsed Multiple Myeloma

In this case, we describe the potential risk of developing an infectious complication leading to a secondary malignancy after a short course of immunotherapy. We report a patient who presented with Epstein-Barr virus (EBV) driven Hodgkin's lymphoma after treatment with a short course of daratumumab along with pomalidomide and dexamethasone for relapsed multiple myeloma. Although there have been limited documented cases of daratumumab treatment leading to EBV reactivation, in patients presenting with infectious symptoms or neutropenia on a daratumumab-based regimen, testing for EBV should not be overlooked.

New aryl-/heteroarylpiperazine derivatives of 1,7-dimethyl-8,9-diphenyl-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5,10-trione: Synthesis and preliminary studies of biological activities

Compounds containing dicarboximide skeleton such as succinimides, maleimides, glutarimides, and phthalimides possess broad biological properties including anti-fungal, antibacterial, antidepressant, or analgesic activities. The piperazine ring is found in a wide range of molecules that have demonstrated a variety of biological functions such as anticancer action and 5-HT receptors agonist/antagonist activity. In the present study, we combined both structures to develop new antitumor agents, a series of piperazine derivatives of 1,7-dimethyl-8,9-diphenyl-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5,10-trione and evaluated their biological activity. The structures of all tested compounds were confirmed by 1H and 13C NMR and by ESI MS spectral analysis. Their cytotoxicity was assessed in vitro against eight human cancer cell lines, namely prostate (PC3), colon (HCT116, SW480, SW620), leukemia (K562), liver (HepG2), lung (A549) and breast (MDA-Mb-231) in contrast to normal HMEC-1 cell line, by using MTT and Trypan blue method. The tested compounds showed significant activity toward cancer cells. The most pronounced cytotoxic effect was observed in K562 and HCT116 with IC50 values below 10 μM for all studied compounds. Importantly, the most promising derivatives for each cancer cell line (IC50 < 10 μM) exerted a weaker cytotoxic effect toward normal HMEC-1 cells than cancer cells. The evaluation of proapoptotic and inhibitory effects on IL-6 release showed that K562 and HCT116 cells were more sensitive to studied compounds than other cancer cell lines. Furthermore, for all piperazine derivatives, the functional activities at the 5-HT1A, D2 receptors as well as their binding affinities at the 5-HT2A, H1 and M receptors, were determined. The current investigation was able to successfully design compounds with both serotoninergic and anticancer properties. It serves as a good starting point for a multimodal approach for the management of cancer and cancer-related symptoms.

Cytomegalovirus and Epstein-Barr virus infection during daratumumab treatment in patients with multiple myeloma

ABSTRACTSWe explored the incidence of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections in 131 patients with multiple myeloma (MM), 53 of whom received daratumumab (Dara) treatments. The Dara group had more RRMM patients than the group without Dara. CMV infection was significantly more common in patients treated with Dara (16.98%) than in patients treated with regimens without Dara (2.56%). During Dara treatments, 24.53% of patients developed CMV and/or EBV infections. Patients who developed infections had significantly lower levels of albumin and lymphocytes in their peripheral blood. The median time from the first Dara infusion to infection was 27 days. We observed NK cell depletion and T cell expansion during Dara-treatment. Patients with CMV and/or EBV infections had significantly lower numbers of NK cells, total T cells, and CD8 + T cells at 1 month, and lower numbers of CD8 + T cells at 2 months after the first Dara infusion than those without infections.

G protein-coupled receptor 183 mediates the sensitization of Burkitt lymphoma tumors to CD47 immune checkpoint blockade by anti-CD20/PI3Kδi dual therapy

Background

Immunotherapy-based regimens have considerably improved the survival rate of B-cell non-Hodgkin lymphoma (B-NHL) patients in the last decades; however, most disease subtypes remain almost incurable. TG-1801, a bispecific antibody that targets CD47 selectively on CD19+ B-cells, is under clinical evaluation in relapsed/refractory (R/R) B-NHL patients either as a single-agent or in combination with ublituximab, a new generation CD20 antibody.

Methods

A set of eight B-NHL cell lines and primary samples were cultured in vitro in the presence of bone marrow-derived stromal cells, M2-polarized primary macrophages, and primary circulating PBMCs as a source of effector cells. Cell response to TG-1801 alone or combined with the U2 regimen associating ublituximab to the PI3Kδ inhibitor umbralisib, was analyzed by proliferation assay, western blot, transcriptomic analysis (qPCR array and RNA sequencing followed by gene set enrichment analysis) and/or quantification of antibody-dependent cell death (ADCC) and antibody-dependent cell phagocytosis (ADCP). CRISPR-Cas9 gene edition was used to selectively abrogate GPR183 gene expression in B-NHL cells. In vivo, drug efficacy was determined in immunodeficient (NSG mice) or immune-competent (chicken embryo chorioallantoic membrane (CAM)) B-NHL xenograft models.

Results

Using a panel of B-NHL co-cultures, we show that TG-1801, by disrupting the CD47-SIRPα axis, potentiates anti-CD20-mediated ADCC and ADCP. This led to a remarkable and durable antitumor effect of the triplet therapy composed by TG-1801 and U2 regimen, in vitro, as well as in mice and CAM xenograft models of B-NHL. Transcriptomic analysis also uncovered the upregulation of the G protein-coupled and inflammatory receptor, GPR183, as a crucial event associated with the efficacy of the triplet combination. Genetic depletion and pharmacological inhibition of GPR183 impaired ADCP initiation, cytoskeleton remodeling and cell migration in 2D and 3D spheroid B-NHL co-cultures, and disrupted macrophage-mediated control of tumor growth in B-NHL CAM xenografts.

Conclusions

Altogether, our results support a crucial role for GPR183 in the recognition and elimination of malignant B cells upon concomitant targeting of CD20, CD47 and PI3Kδ, and warrant further clinical evaluation of this triplet regimen in B-NHL.

Inhibitory effect and related mechanism of decitabine combined with gemcitabine on proliferation of NK/T cell lymphoma cells

Background: EBV-associated lymphoma is a neoplasm with a poor prognosis, highly aggressive, and progressive rapidly. There is no standard clinical treatment protocol. Decitabine and gemcitabine are known to have anticancer properties against cells of various cancer, respectively. However, the effect of the combination medication on NK/T cell lymphoma cells and potential mechanisms have not been thoroughly investigated. Methods: Human NK/T cell lymphoma cells NK92MI were treated with decitabine and gemcitabine alone or in combination. Experiments, including the Cell Counting Kit-8 and flow cytometry, were performed to investigate how the combination of decitabine and gemcitabine affects the biological behavior of NK92MI cells in vitro. mRNA sequencing, RT-PCR, and western blotting were used to detect changes in the related signal pathway, mRNA, and protein expressions. Results: Decitabine and gemcitabine significantly inhibited the viability and proliferation of NK92MI cells in a dose-dependent manner. The combination index was less than 1 after treating with two drugs, which was a significant synergistic effect. The decitabine concentration with the best synergistic effect was 4.046 µM, and the gemcitabine concentration was 0.005 µM. Flow cytometry showed that combining two drugs could significantly promote apoptosis and arrest the cell cycle at the S phase. In the combined DAC and GEM group, caspase3 protein levels were higher than in either group alone or the control group. The transcriptome sequence, KEGG, and PPI analysis showed that the differential genes after combined treatment were mainly enriched in signal pathways related to cell proliferation, adhesion, and migration compared with using alone and control groups. Based on the sequencing results, we further investigated the role of DAC and GEM in ferroptosis-related signaling molecules using RT-PCR and Western blot techniques. RT-PCR and western blotting showed that the expression levels of HMOX1 and EBV cleavage gene BRLF1 were higher in the group with combined DAC and GEM than in the group alone and the control group, while the protein and mRNA expression levels of SLC7A11 were lower than the others. In addition, the GPX4 protein expression level in the combination group was lower than in the drug-alone and control groups. In addition, the combination treatment increased the ROS level of NK92MI cells. Conclusion: Our current findings suggested that decitabine had an inhibitory effect on the proliferation of NK92MI cells when co-treated with gemcitabine. This combination may increase the expression of ferroptosis-related signaling molecules, thus inhibiting the proliferation of NK92MI cells. It also promoted apoptosis in NK/T cell lymphoma. For patients with NK/T cell lymphoma, this novel combination may provide clinical benefits.

Development of Epstein-Barr virus-associated lymphoproliferative disorder and hemophagocytic lymphohistiocytosis during long-term lenalidomide maintenance therapy in multiple myeloma

Reactivation of Epstein-Barr virus (EBV) has been considered a very rare event among patients on immunomodulatory drugs (IMiDs) such as lenalidomide, and an association between the two has not well been recognized. We have recently experienced a rare case of multiple myeloma in which the patient had suffered EBV reactivation during long-term lenalidomide maintenance therapy. The patient subsequently developed EBV-associated lymphoproliferative disease (LPD) as well as EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH), which was fatal despite intensive treatment. Although rare, clinicians should be aware that such fatal EBV reactivation could occur as a minor yet critical complication of long-term maintenance therapy with IMiDs in multiple myeloma patients. Regular monitoring and early detection of EBV reactivation would be beneficial for these patients, so that proper diagnostic examinations can be initiated without delay.

Post-marketing safety of immunomodulatory drugs in multiple myeloma: A pharmacovigilance investigation based on the FDA adverse event reporting system

Objective: In recent years, the emergence of immunomodulatory drugs (IMiDs) has significantly improved clinical outcomes in patients with multiple myeloma (MM); however, serious adverse events (AEs) have hindered their safe clinical application. This study aimed to characterize the safety profiles and differences in IMiDs through a disproportionality analysis using the U.S. Food and Drug Administration Adverse Event Reporting System (FAERS), a post-marketing surveillance database. Methods: This study filtered reports of thalidomide, lenalidomide, and pomalidomide as primary suspect drugs in FAERS files from January 2013 to December 2021. AEs in the reports were retrieved according to the preferred terms (PTs) of the Medical Dictionary for Regulatory Activities. Furthermore, we detected safety signals using the reporting odds ratio (ROR), proportional reporting ratio (PRR), and Bayesian belief propagation neural network (BCPNN). When all three algorithms showed an association between the target drug and the AE, a positive signal was generated. Results: We extracted 9,968 thalidomide, 231,926 lenalidomide, and 55,066 pomalidomide AE reports. AEs were more common in male patients and in those >44 years old. Important safety signals were detected based on the system organ classes (SOC), including thalidomide (cardiac disorders: ROR, 2.87; PRR, 2.79; IC 1.22), lenalidomide (gastrointestinal disorders: ROR, 2.38; PRR, 2.27; IC 0.75), and pomalidomide (respiratory, thoracic, and mediastinal disorders: ROR, 2.14; PRR, 2.09; IC 0.85). Within the PT level, we identified novel risk signals: the thalidomide-induced second primary malignancy (SPM) signal was significant; lenalidomide reduced the success rate of hematopoietic stem cell collection; and three IMiDs may cause human chorionic gonadotropin increase, but this needs to be proven by clinical data. Pneumonia, sepsis, and renal failure are common risk factors for death due to IMiDs. Compared with thalidomide and lenalidomide, pomalidomide has a lower risk of venous thromboembolism (VTE) and is beneficial to patients with renal insufficiency. Conclusion: Mining data from FAERS resulted in novel AE signals, including adenocarcinoma of colon, harvest failure of blood stem cells, and increased levels of human chorionic gonadotropin. Further investigation is required to verify the significance of these signals. Moreover, IMiDs showed differences in safety reports, which should be emphasized by clinicians.

Recent Advances in Adult Post-Transplant Lymphoproliferative Disorder

PTLD is a rare but severe complication of hematopoietic or solid organ transplant recipients, with variable incidence and timing of occurrence depending on different patient-, therapy-, and transplant-related factors. The pathogenesis of PTLD is complex, with most cases of early PLTD having a strong association with Epstein-Barr virus (EBV) infection and the iatrogenic, immunosuppression-related decrease in T-cell immune surveillance. Without appropriate T-cell response, EBV-infected B cells persist and proliferate, resulting in malignant transformation. Classification is based on the histologic subtype and ranges from nondestructive hyperplasias to monoclonal aggressive lymphomas, with the most common subtype being diffuse large B-cell lymphoma-like PTLD. Management focuses on prevention of PTLD development, as well as therapy for active disease. Treatment is largely based on the histologic subtype. However, given lack of clinical trials providing evidence-based data on PLTD therapy-related outcomes, there are no specific management guidelines. In this review, we discuss the pathogenesis, histologic classification, and risk factors of PTLD. We further focus on common preventive and frontline treatment modalities, as well as describe the application of novel therapies for PLTD and elaborate on potential challenges in therapy.

Epstein-Barr virus-associated posttransplant lymphoproliferative disorders: new insights in pathogenesis, classification and treatment

PURPOSE OF REVIEW

Posttransplant lymphoproliferative disorder (PTLD) is a serious complication following transplantation from an allogeneic donor. Epstein-Barr Virus (EBV) is involved in a substantial number of cases. In this review, we aim to summarize recent knowledge on pathogenesis, classification and treatment of EBV + PTLD.

RECENT FINDINGS

New insights in the complex oncogenic properties of EBV antigens noncoding Ribonucleic acids (RNAs), especially EBV MicroRNA (miRNAs), have increased our knowledge of the pathogenesis of EBV + PTLD. In addition the potential influence of EBV on the tumor microenvironment is becoming clearer, paving the way for new types of immunotherapy. Currently PTLD is classified according to the World Health Organization classification together with other lymphoproliferative disorders, based on the specific immunosuppression. However, a new framework integrating all types of lymphoproliferative disorders in all different settings of immune deficiency and dysregulation is needed. Although treatment of EBV + and EBV - PTLD was largely similar in the past, EBV-directed therapies are currently increasingly used.

SUMMARY

The use of EBV-directed therapies and new agents, based on better understanding of pathogenesis and classification of PTLD, will change the treatment landscape of EBV + PTLD in the next era.

B cell-targeted therapies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology that primarily affects women of childbearing age. There is no disease more heterogeneous than SLE as patients experience a myriad of manifestations and unpredictable periods of heightened disease activity. This heterogeneity not only makes it difficult for treatment decisions and prognostication, but has made drug development quite challenging. Despite these challenges, belimumab, voclosporin, and anifromulab, approved by the United States Food and Drug Administration (FDA) to treat SLE or lupus nephritis (LN), enhanced our armamentarium of traditional therapies, such as hydroxychloroquine, corticosteroids, and immunosuppressives. However, there remains a dire need to develop therapies that offer greater efficacy and safety. Patients with SLE produce excessive amounts of autoantibodies and cytokines that result in inflammation and organ damage. While a considerable number of potential drug development targets exist, there has been much attention focused on B cells. Strategies have included direct B cell killing, modulation of B cell function, inhibition of molecules essential to B cell growth and survival, and acceleration of autoantibody clearance, to name just a few. In this article, we review SLE clinical trials evaluating experimental agents that target B cells or plasma cells.

Double-drug loading upconversion nanoparticles for monitoring and therapy of a MYC/BCL6-positive double-hit diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a systemic hematological malignancy. Herein, through whole exome sequencing (WES), we found that DLBCL genome changes and expression characteristics are associated with various immune cells. Lenalidomide (Len) is a leading candidate for the immunomodulatory treatment of multiple myeloma in the clinic. Inspired by lenalidomide as an immunomodulatory drug for the treatment of multiple myeloma, we constructed a multifunctional nanoplatform with therapeutic and imaging properties for DLBCL by co-loading lenalidomide and dexamethasone (Dex) with upconversion nanoparticles using a GSH-sensitive linker (named as UCNPs-Len-Dex). In vitro cell experiments proved that the UCNPs-Len-Dex had good biocompatibility and obvious antitumor efficacy. UCNPs-Len-Dex also exhibited excellent anti-tumor efficacy and imaging properties in vivo. RNA sequencing showed that UCNPs-Len-Dex targeted and activated the E3 ligase of CRBN, resulting in IKZF1/3 degradation, which inhibited MYC/BCL6-positive DLBCL and maintained the stability of the immune microenvironment. Therefore, this study provided a new monitoring and therapeutic synergetic strategy for DLBCL.

Promising Response to Lenalidomide-Combination Therapy in a Discordant Lymphoma Consisting of EBV-Positive Diffuse Large B-Cell Lymphoma and Angioimmunoblastic T-Cell Lymphoma: A Case Report

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL) complicated with angioimmunoblastic T-cell lymphoma (AITL) is extremely rare and typically shows an aggressive clinical course and unsatisfactory prognosis. Here, we describe the case of a 77-year-old man who was referred to the hospital because of repeated fever, night sweats, and weight loss. He was finally diagnosed with a discordant lymphoma consisting of AITL and DLBCL, with significantly different maximum standardized uptake values on positron emission tomography/computed tomography. Based on his complex illness and poor performance status, the patient received six cycles of lenalidomide combined with R-miniCHOP regimen and achieved complete remission with tolerable and controlled toxicity. He subsequently received lenalidomide maintenance therapy and achieved sustained remission. We consider the possible causes of this discordance involved AITL and EBV-positive DLBCL, and the possible mechanism of lenalidomide action in both T-cell and B-cell non-Hodgkin lymphomas. Lenalidomide-combination therapy may be a preferable choice in patients with an EBV-associated discordant lymphoma.

First reported case of secondary mixed phenotype acute leukemia after multiple myeloma

In recent years the outcome of patients with multiple myeloma (MM) has significantly improved, due to new drugs. However, some agents, i.e. the alkylating drug melphalan, can be associated with an increased incidence of secondary malignancies. Myelodysplastic syndromes and acute myeloid leukemia are reported in the literature, and rarely acute lymphoblastic leukemia. Here we describe a unique case of a 56-years old female patient affected by MM since 2015 in complete remission after autologous stem cell transplant and in lenalidomide maintenance, who developed 2 years later mixed phenotype acute leukemia (MPAL). The patient, refractory to both lymphoblastic and myeloid acute leukemia regimens, achieved complete remission with bi-specific anti-CD19/anti-CD3 monoclonal antibody blinatumomab and with hypomethylating agent azacytidine plus the BCL-2 inhibitor venetoclax. She then underwent hematopoietic stem cell transplantation from HLA-identical sibling donor and she is still in complete remission after 9 months. To the best of our knowledge, there are no cases in the literature describing MPAL after autologous transplant for MM. Our patient was treated with blinatumomab and venetoclax and achieved complete remission 9 months from allogeneic transplant. The mechanism underlying the development of MPAL is not completely understood and therapies are still lacking. In this context the combination of blinatumomab, azacytidine and venetoclax successfully used in this patient may provide food for thought for further studies in this rare setting of patients.

Bystander Memory T Cells and IMiD/Checkpoint Therapy in Multiple Myeloma: A Dangerous Tango?

In this review article we discuss the role of the memory T cells in multiple myeloma (MM) and how they may influence immune responses in patients that received immunomodulating drugs and check point therapy.

Pomalidomide restores immune recognition of primary effusion lymphoma through upregulation of ICAM-1 and B7-2

Pomalidomide (Pom) is an immunomodulatory drug that has efficacy against Kaposi’s sarcoma, a tumor caused by Kaposi’s sarcoma-associated herpesvirus (KSHV). Pom also induces direct cytotoxicity in primary effusion lymphoma (PEL), a B-cell malignancy caused by KSHV, in part through downregulation of IRF4, cMyc, and CK1α as a result of its interaction with cereblon, a cellular E3 ubiquitin ligase. Additionally, Pom can reverse KSHV-induced downregulation of MHCI and co-stimulatory immune surface molecules ICAM-1 and B7-2 on PELs. Here, we show for the first time that Pom-induced increases in ICAM-1 and B7-2 on PEL cells lead to an increase in both T-cell activation and NK-mediated cytotoxicity against PEL. The increase in T-cell activation can be prevented by blocking ICAM-1 and/or B7-2 on the PEL cell surface, suggesting that both ICAM-1 and B7-2 are important for T-cell co-stimulation by PELs. To gain mechanistic insights into Pom’s effects on surface markers, we generated Pom-resistant (PomR) PEL cells, which showed about 90% reduction in cereblon protein level and only minimal changes in IRF4 and cMyc upon Pom treatment. Pom no longer upregulated ICAM-1 and B7-2 on the surface of PomR cells, nor did it increase T-cell and NK-cell activation. Cereblon-knockout cells behaved similarly to the pomR cells upon Pom-treatment, suggesting that Pom’s interaction with cereblon is necessary for these effects. Further mechanistic studies revealed PI3K signaling pathway as being important for Pom-induced increases in these molecules. These observations provide a rationale for the study of Pom as therapy in treating PEL and other KSHV-associated tumors.

Primary effusion lymphoma (PEL) is an aggressive B-cell lymphoma caused by Kaposi’s sarcoma-associated herpesvirus (KSHV). KSHV encodes various genes that enable infected cells to evade recognition and elimination by the immune system. PEL cells are poorly recognized by T-cells and NK cells, partly due to KSHV-induced downregulation of immune stimulatory surface molecules ICAM-1 and B7-2. We previously found that a cereblon-binding immunomodulatory drug pomalidomide (Pom) can restore the levels of these markers on PELs. Here, we show that the increases in ICAM-1 and B7-2 induced by Pom leads to a functional increase in the recognition and killing of PELs by both T-cells and NK cells. Further, exposure of both the PEL cells and T-cells to Pom lead to an even higher T-cell stimulation providing strong evidence that Pom could help PEL patients by providing specific immune-stimulatory effect. We further perform mechanistic studies and show that Pom’s cellular binding partner cereblon as well as the PI3K pathway are important for Pom-mediated increases in these surface markers.

Pathobiology and treatment of lymphomatoid granulomatosis, a rare EBV-driven disorder

Lymphomatoid granulomatosis (LYG) is a rare Epstein-Barr virus (EBV)-driven B-cell lymphoproliferative disease (LPD). This disease is hypothesized to result from defective immune surveillance of EBV, with most patients showing evidence of immune dysfunction, despite no known primary immunodeficiency. Pathologically, LYG is graded by the number and density of EBV+ atypical B cells, and other characteristic findings include an angioinvasive/angiodestructive reactive T-cell infiltrate and various degrees of necrosis. Clinically, LYG universally involves the lungs with other common extranodal sites, including skin, central nervous system, liver, and kidneys. Nodal and/or bone marrow involvement is extremely rare and, if present, suggests an alternative diagnosis. Treatment selection is based on histologic grade and underlying pathobiology with low-grade disease hypothesized to be immune-dependent and typically polyclonal and high-grade disease to be immune-independent and typically oligoclonal or monoclonal. Methods of augmenting the immune response to EBV in low-grade LYG include treatment with interferon-α2b, whereas high-grade disease requires immunochemotherapy. Given the underlying defective immune surveillance of EBV, patients with high-grade disease may have a recurrence in the form of low-grade disease after immunochemotherapy, and those with low-grade disease may progress to high-grade disease after immune modulation, which can be effectively managed with crossover treatment. In patients with primary refractory disease or in those with multiple relapses, hematopoietic stem cell transplantation may be considered, but its efficacy is not well established. This review discusses the pathogenesis of LYG and highlights distinct histopathologic and clinical features that distinguish this disorder from other EBV+ B-cell LPDs and lymphomas. Treatment options, including immune modulation and combination immunochemotherapy, are discussed.

ARID2 is a pomalidomide-dependent CRL4CRBN substrate in multiple myeloma cells

The immunomodulatory drug (IMiD) thalidomide and its derivatives lenalidomide and pomalidomide are therapeutic agents used in the treatment of multiple myeloma. Although pomalidomide offers considerable clinical benefits to patients with lenalidomide-resistant multiple myeloma, the molecular mechanisms underlying its superior efficacy remain unclear. Here we show that ARID2, a component of the polybromo-associated BAF (PBAF) chromatin-remodeling complex, is a pomalidomide-induced neosubstrate of CRL4^CRBN. BRD7, another subunit of PBAF, is critical for pomalidomide-induced ARID2 degradation. ARID2 is involved in transcriptional regulation of pomalidomide target genes including MYC. Pomalidomide is more effective than lenalidomide in degrading ARID2 and is capable of inhibiting MYC expression and proliferation in lenalidomide-resistant cell lines. Notably, ARID2 expression is associated with a poor prognosis and is higher in chemoresistant minimal residual disease (MRD) populations, and in patients with relapsed/refractory multiple myeloma. These findings suggest that ARID2 is a promising target for overcoming lenalidomide resistance in patients with multiple myeloma.

Lytic Induction Therapy against Epstein-Barr Virus-Associated Malignancies: Past, Present, and Future

Epstein-Barr virus (EBV) lytic induction therapy is an emerging virus-targeted therapeutic approach that exploits the presence of EBV in tumor cells to confer specific killing effects against EBV-associated malignancies. Efforts have been made in the past years to uncover the mechanisms of EBV latent-lytic switch and discover different classes of chemical compounds that can reactivate the EBV lytic cycle. Despite the growing list of compounds showing potential to be used in the lytic induction therapy, only a few are being tested in clinical trials, with varying degrees of success. This review will summarize the current knowledge on EBV lytic reactivation, the major hurdles of translating the lytic induction therapy into clinical settings, and highlight some potential strategies in the future development of this therapy for EBV-related lymphoid and epithelial malignancies.

The Evolution of Dendritic Cell Immunotherapy against HIV-1 Infection: Improvements and Outlook

Dendritic cells (DC) are key phagocytic cells that play crucial roles in both the innate and adaptive immune responses against the human immunodeficiency virus type 1 (HIV-1). By processing and presenting pathogen-derived antigens, dendritic cells initiate a directed response against infected cells. They activate the adaptive immune system upon recognition of pathogen-associated molecular patterns (PAMPs) on infected cells. During the course of HIV-1 infection, a successful adaptive (cytotoxic CD8⁺ T-cell) response is necessary for preventing the progression and spread of infection in a variety of cells. Dendritic cells have thus been recognized as a valuable tool in the development of immunotherapeutic approaches and vaccines effective against HIV-1. The advancements in dendritic cell vaccines in cancers have paved the way for applications of this form of immunotherapy to HIV-1 infection. Clinical trials with patients infected with HIV-1 who are well-suppressed by antiretroviral therapy (ART) were recently performed to assess the efficacy of DC vaccines, with the goal of mounting an HIV-1 antigen-specific T-cell response, ideally to clear infection and eliminate the need for long-term ART. This review summarizes and compares methods and efficacies of a number of DC vaccine trials utilizing autologous dendritic cells loaded with HIV-1 antigens. The potential for advancement and novel strategies of improving efficacy of this type of immunotherapy is also discussed.

Biological Difference Between Epstein-Barr Virus Positive and Negative Post-transplant Lymphoproliferative Disorders and Their Clinical Impact

Epstein–Barr virus (EBV) infection is correlated with several lymphoproliferative disorders, including Hodgkin disease, Burkitt lymphoma, diffuse large B-cell lymphoma (DLBCL), and post-transplant lymphoproliferative disorder (PTLD). The oncogenic EBV is present in 80% of PTLD. EBV infection influences immune response and has a causative role in the oncogenic transformation of lymphocytes. The development of PTLD is the consequence of an imbalance between immunosurveillance and immunosuppression. Different approaches have been proposed to treat this disorder, including suppression of the EBV viral load, reduction of immune suppression, and malignant clone destruction. In some cases, upfront chemotherapy offers better and durable clinical responses. In this work, we elucidate the clinicopathological and molecular-genetic characteristics of PTLD to clarify the biological differences of EBV(+) and EBV(–) PTLD. Gene expression profiling, next-generation sequencing, and microRNA profiles have recently provided many data that explore PTLD pathogenic mechanisms and identify potential therapeutic targets. This article aims to explore new insights into clinical behavior and pathogenesis of EBV(–)/(+) PTLD with the hope to support future therapeutic studies.

Epstein-Barr Virus-Associated Post-Transplant Lymphoproliferative Disorders after Hematopoietic Stem Cell Transplantation: Pathogenesis, Risk Factors and Clinical Outcomes

Epstein-Barr virus (EBV) is a ubiquitous virus belonging to the human γ-herpes virus subfamily. After primary infection, EBV maintains a life-long latent infection. A major concern is that EBV can cause a diverse range of neoplasms and autoimmune diseases. In addition, patients undergoing hematopoietic stem cell transplantation or solid organ transplantation can experience post-transplant lymphoproliferative disorders (PTLDs) due to dysfunction or suppression of host’s immune system, or uncontrolled proliferation of EBV-infected cells. In recent years, the number of EBV-associated PTLD cases has increased. This review focuses on the current understandings of EBV-associated PTLD pathogenesis, as well as the risk factors and clinical outcomes for patients after allogeneic stem cell transplantation.

Acylglycerol kinase promotes tumour growth and metastasis via activating the PI3K/AKT/GSK3β signalling pathway in renal cell carcinoma

BACKGROUND

Clinically, the median survival in patients with metastatic renal cell carcinoma (RCC) was only 6-12 months and a 5-year survival rate of less than 20%. Therefore, an in-depth study of the molecular mechanisms involved in RCC is of great significance for improving the survival of patients with advanced RCC. Acylglycerol kinase (AGK) is a newly discovered lipid kinase that has been reported to be a potent oncogene that may be involved in the regulation of malignant progression in a variety of tumours. However, the expression and biological characteristics of the AGK gene in RCC remain unclear.

METHODS

AGK expression was quantified by quantitative real-time PCR, Western blotting and immunohistochemistry in RCC cell lines and paired patient tissues. Kaplan-Meier method and Cox proportional hazards models were used to evaluate the prognostic value of AGK in human RCC tissue samples. Chi-squared test was performed to analyse the correlation between AGK expression and the clinicopathological features. Stable overexpression and knockdown of AGK in RCC cells was constructed with lentivirus. The oncogenic effects of AGK in human RCC progression were investigated using assays of colony formation, anchorage-independent growth, EdU assay, cell cycle analysis, wound-healing, trans-well analysis and xenograft tumour model. GSEA and KEGG analysis were conducted to detect the potential pathway of AGK involved in RCC. These results were further confirmed using the luciferase reporter assays, immunofluorescence and in vivo experiments.

RESULTS

AGK expression is significantly elevated in RCC and closely related to the malignant development and poor prognosis in RCC patients. By in vitro and in vivo experiments, AGK was shown to enhance the proliferation of RCC cells by promoting the transition from the G1 phase to the S phase in the cell cycle and to enhance the migration and invasion by promoting epithelial-mesenchymal transition. By activating the PI3K/AKT/GSK3β signalling pathway in RCC, AGK can increase nuclear accumulation of β-catenin, which further upregulated TCF/LEF transcription factor activity.

CONCLUSIONS

AGK promotes the progression of RCC via activating the PI3K/AKT/GSK3β signalling pathway and might be a potential target for the further research of RCC.

B-cell acute lymphoblastic leukemia in an elderly man with plasma cell myeloma and long-term exposure to thalidomide and lenalidomide: a case report and literature review

BACKGROUND

The advent of the immunomodulatory imide drugs (IMiDs) lenalidomide and thalidomide for the treatment of patients with plasma cell myeloma (PCM), has contributed to more than a doubling of the overall survival of these individuals. As a result, PCM patients join survivors of other malignancies such as breast and prostate cancer with a relatively new clinical problem - second primary malignancies (SPMs) - many of which are a result of the treatment of the initial cancer. PCM patients have a statistically significant increased risk for acute myeloid leukemia (AML) and Kaposi sarcoma. IMiD treatment has also been associated with an increased risk of myelodysplastic syndrome (MDS), AML, and squamous cell carcinoma of the skin. However, within these overlapping groups, acute lymphoblastic leukemia (ALL) is much less common.

CASE PRESENTATION

Herein, we describe an elderly man with PCM and a 14-year cumulative history of IMiD therapy who developed persistent pancytopenia and was diagnosed with B-cell acute lymphoblastic leukemia (B-ALL). He joins a group of 17 other patients documented in the literature who have followed a similar sequence of events starting with worsening cytopenias while on IMiD maintenance for PCM. These PCM patients were diagnosed with B-ALL after a median time of 36 months after starting IMiD therapy and at a median age of 61.5 years old.

CONCLUSIONS

PCM patients with subsequent B-ALL have a poorer prognosis than their de novo B-ALL counterparts, however, the very low prevalence rate of subsequent B-ALL and high efficacy of IMiD maintenance therapy in PCM should not alter physicians' current practice. Instead, there should be a low threshold for bone marrow biopsy for unexplained cytopenias.

A new therapy in Epstein-Barr virus-associated lymphoproliferative disease: a case report and a revision of the literature

Background

Systemic chronic active Epstein-Barr virus infection is an extremely rare childhood disease. Since chronic active Epstein-Barr virus infection can trigger the onset of Epstein-Barr virus-associated lymphoproliferative disease. The clinical manifestations of the disease vary according to the site of involvement; therefore, management may be challenging. Currently, there are no standardized guidelines for treating Chronic active Epstein-Barr virus infection effectively.

Case presentation

We report a case of chronic active Epstein-Barr virus infection in a 5-year-old Chinese boy with intestinal, vascular, and neurological involvement. At age of 2 years and 7 months old, he had hepatomegaly and been diagnosed with Epstein-Barr virus infection. After treatment, he showed some clinical improvement. At age of 3 years and 3 months old, he presented with recurrent fever and diarrhea. Then he received methylprednisolone for 1 year and his symptoms ameliorated. At the age of 5 years, his symptoms recurred and had gastrointestinal hemorrhage and developed polyuria, frequent convulsions and hyponatremia. He was transferred to our hospital for further management. He was unconscious on admission and was diagnosised Epstein-Barr virus-lymphoproliferative disorder, based on the results in situ hybridization of EBV-encoded miRNA in sigmoid colon. Three-dimensional CT angiography demonstrated an aneurysm in the right internal carotid artery. Abdominal CT showed dilatation of vessels in part of the intestinal wall. He was also diagnosised Epstein-Barr virus encephalitis based on the elevated Epstein-Barr virus antibody titers and presence of Epstein-Barr virus DNA in the Cerebrospinal Fluid.

A repeated duodenal artery embolization and symptomatic therapy could not control the hemorrhage after admission. He subsequently received treatment with ganciclovir, glucocorticoid, thalidomide, and propranolol. Hemorrhage was controlled in 5 days; his symptoms improved. The fever did not recur and the CSF pressure was also normalized. A follow-up CT at 3 months after admission showed regression of the aneurysm in the right internal carotid artery and the vascular lesion in the duodenum.

Discussion and conclusions

A new treatment protocol including thalidomide and propranolol resulted in a marked improvement in his clinical symptoms, and shows promise as a novel and effective therapeutic approach for Chronic active Epstein-Barr virus infection-associated lymphoproliferative disorder.

Pharmacologic Activation of Lytic Epstein-Barr Virus Gene Expression without Virion Production

Several therapeutic strategies targeting Epstein-Barr virus (EBV)-associated tumors involve upregulation of viral lytic gene expression. Evidence has been presented that the unfolded protein response (UPR) leads to EBV lytic gene expression. Clofoctol, an antibacterial antibiotic, has been reported to upregulate the UPR in prostate cancer cell lines and to slow their growth. We investigated the effects of clofoctol on an EBV-positive Burkitt lymphoma cell line and confirmed the upregulation of all three branches of the UPR and activation of EBV lytic gene expression. While immediate early, early, and late EBV RNAs were all upregulated, immediate early and early viral proteins but not late viral proteins were expressed. Furthermore, infectious virions were not produced. The use of clofoctol in combination with a protein kinase R-like endoplasmic reticulum kinase inhibitor led to expression of late viral proteins. The effects of clofoctol on EBV lytic protein upregulation were not limited to lymphoid tumor cell lines but also occurred in naturally infected epithelial gastric cancer and nasopharyngeal cancer cell lines. An agent that upregulates lytic viral protein expression but that does not lead to the production of infectious virions may have particular value for lytic induction strategies in the clinical setting.IMPORTANCE Epstein-Barr virus is associated with many different cancers. In these cancers the viral genome is predominantly latent; i.e., most viral genes are not expressed, most viral proteins are not synthesized, and new virions are not produced. Some strategies for treating these cancers involve activation of lytic viral gene expression. We identify an antibacterial antibiotic, clofoctol, that is an activator of EBV lytic RNA and protein expression but that does not lead to virion production.

Viral-Targeted Strategies Against EBV-Associated Lymphoproliferative Diseases

Epstein-Barr virus (EBV) is strongly associated with a spectrum of EBV-associated lymphoproliferative diseases (EBV-LPDs) ranging from post-transplant lymphoproliferative disorder, B cell lymphomas (e.g., endemic Burkitt lymphoma, Hodgkin lymphoma, and diffuse large B cell lymphoma) to NK or T cell lymphoma (e.g., nasal NK/T-cell lymphoma). The virus expresses a number of latent viral proteins which are able to manipulate cell cycle and cell death processes to promote survival of the tumor cells. Several FDA-approved drugs or novel compounds have been shown to induce killing of some of the EBV-LPDs by inhibiting the function of latent viral proteins or activating the viral lytic cycle from latency. Here, we aim to provide an overview on the mechanisms by which EBV employs to drive the pathogenesis of various EBV-LPDs and to maintain the survival of the tumor cells followed by a discussion on the development of viral-targeted strategies based on the understanding of the patho-mechanisms.

Pomalidomide increases immune surface marker expression and immune recognition of oncovirus-infected cells

Most chronic viruses evade T-cell and natural killer (NK) immunity through downregulation of immune surface markers. Previously we showed that Pomalidomide (Pom) increases surface expression of major histocompatibility complex class I (MHC-I) in Kaposi sarcoma-associated herpesvirus-infected latent and lytic cells and restores ICAM-1 and B7-2 in latent cells. We explored the ability of Pom to increase immune surface marker expression in cells infected by other chronic viruses, including human T-cell leukemia virus type-1 (HTLV-1), Epstein-Barr virus (EBV), human papilloma virus (HPV), Merkel cell polyoma virus (MCV), and human immunodeficiency virus type-1 (HIV-1). Pom increased MHC-1, ICAM-1, and B7-2/CD86 in immortalized T-cell lines productively infected with HTLV-1 and also significantly increased their susceptibility to NK cell-mediated cytotoxicity. Pom enhancement of MHC-I and ICAM-1 in primary cells infected with HTLV-1 was abrogated by knockout of HTLV-1 orf-1. Pom increased expression of ICAM-1, B7-2 and MHC class I polypeptide related sequence A (MICA) surface expression in the EBV-infected Daudi cells and increased their T-cell activation and susceptibility to NK cells. Moreover, Pom increased expression of certain of these surface markers on Akata, Raji, and EBV lymphoblastic cell lines. The increased expression of immune surface markers in these virus-infected lines was generally associated with a decrease in IRF4 expression. By contrast, Pom treatment of HPV, MCV and HIV-1 infected cells did not increase these immune surface markers. Pom and related drugs may be clinically beneficial for the treatment of HTLV-1 and EBV-induced tumors by rendering infected cells more susceptible to both innate and adaptive host immune responses.

Epigenetic crossroads of the Epstein-Barr virus B-cell relationship

Epstein-Barr virus (EBV) is a gamma-herpesvirus that establishes lifelong infection in the majority of people worldwide. EBV uses epigenetic reprogramming to switch between multiple latency states in order to colonize the memory B-cell compartment and to then periodically undergo lytic reactivation upon plasma cell differentiation. This review focuses on recent advances in the understanding of epigenetic mechanisms that EBV uses to control its lifecycle and to subvert the growth and survival pathways that underly EBV-driven B-cell differentiation versus B-cell growth transformation, a hallmark of the first human tumor virus. These include the formation of viral super enhancers that drive expression of key host dependency factors, evasion of tumor suppressor responses, prevention of plasmablast differentiation, and regulation of the B-cell lytic switch.

Acute Lymphoblastic Leukemia following Lenalidomide Maintenance for Multiple Myeloma: Two Cases with Unexpected Presentation and Good Prognostic Features

Lenalidomide maintenance following autologous stem cell transplant (ASCT) is considered the standard of care for eligible patients with multiple myeloma (MM). A recent meta-analysis has provided additional evidence that lenalidomide maintenance is associated with a higher incidence of second primary malignancies, including both hematologic and solid malignancies. Acute lymphoblastic leukemia (ALL) as a second primary malignancy is rarely described in the literature. Herein, we describe two patients with MM treated with induction therapy, ASCT, and lenalidomide maintenance that experienced cytopenias while on maintenance. ALL was unexpectedly diagnosed on bone marrow biopsy. One patient was diagnosed on routine biopsy performed as part of requirements of the clinical trial. Both patients had B-cell ALL, without known poor risk cytogenetics, and were managed with standard induction therapies resulting in complete remission. We also reviewed the literature for similar cases of secondary ALL (sALL) in MM patients exposed to immunomodulatory drugs (IMiDs). In conclusion, persistent cytopenias in responding MM patients receiving IMiDs maintenance should be an indication for bone marrow biopsy. Patients develop sALL after median of 32.5 months (range, 20–84) from being on lenalidomide or thalidomide maintenance, often presenting with cytopenias, display low tolerance to chemotherapy, but remission can often be achieved.

Cancer Therapy-associated Lymphoproliferative Disorders: An Under-recognized Type of Immunodeficiency-associated Lymphoproliferative Disorder

We describe the clinicopathologic features of 17 patients who had a hematologic malignancy of various types, were treated, and subsequently developed a lymphoproliferative disorder (LPD). There were 10 men and 7 women with a median age of 59 years (range, 36 to 83 y). The primary hematologic neoplasms included: 5 chronic lymphocytic leukemia/small lymphocytic lymphoma, 3 plasma cell myeloma, 2 acute monoblastic leukemia, and 1 case each of mixed-phenotype acute leukemia, chronic myeloid leukemia, splenic marginal zone lymphoma, follicular lymphoma, mantle cell lymphoma, T-cell prolymphocytic leukemia, and peripheral T-cell lymphoma. All patients were treated with chemotherapy with or without therapeutic antibodies; 3 also underwent autologous stem cell transplantation. The mean interval from initiation of therapy for initial hematologic malignancy to onset of LPD was 66 months (range, 3 to 299 mo). Ten (59%) LPDs were extranodal and 7 (41%) involved nodal tissues. The histologic diagnoses included: 8 diffuse large B-cell lymphoma, 4 classical Hodgkin lymphoma, 3 polymorphic LPD, 1 lymphomatoid granulomatosis, and 1 Epstein-Barr virus (EBV) mucocutaneous ulcer. Fourteen cases were EBV. Following the onset of LPD, chemotherapy was administered to 10 (59%) patients. With a median follow-up of 100 months (range, 5 to 328 mo), 8 (47%) patients are alive and 9 (53%) died. One (6%) patient with lymphomatoid granulomatosis underwent spontaneous remission. On the basis of the clinicopathologic features and high prevalence of EBV infection in this cohort, we believe that these LPDs show similarities with other types of immunodeficiency-associated LPDs. We suggest that cancer therapy-associated LPD be included in future classification systems for immunodeficiency-associated LPDs.