Primary Effusion Lymphoma Patients Research Articles

Abstract 4857: Contemporary hospital-based study examining demographics, treatment patterns and survival outcomes of primary effusion lymphoma in the United States, with a specific emphasis on Hispanics

Abstract Background: Primary effusion lymphoma (PEL) is a rare and aggressive non-Hodgkin lymphoma associated with HIV and human herpesvirus 8 (HHV-8). (Blood PMID: 8695812). Without treatment, patients typically survive only two to three months (Oncol Res Treat PMID: 28253516) Limited research has been conducted on PEL, particularly in minorities in the United States. Limited research, especially in minority populations (Blood PMID: 30154110), has prompted a nationwide study comparing demographics, clinical characteristics, treatment patterns, and survival outcomes between Hispanic (HI) and Non-Hispanic (NH) PEL patients. Methods: Data on PEL patients from the National Cancer Database (NCDB) between 2004 and 2019 were analyzed in the US. Demographics and treatment characteristics were compared across ethnic groups. Kaplan-Meier and Cox regression analyses were used to compare overall survival (OS) between HI and NH populations. Multivariate analysis and propensity score matching were conducted, adjusting for age, stage, co-morbidity score, insurance status, type of facility, and great circle distance. Results: Of 459 PEL patients, 18% were HI, and 79% were NH. Both groups had mostly male patients (87% vs. 86%). HI patients were younger at diagnosis (mean 49 years vs. 57 years, p=0.163). Diagnoses were mostly from 2014-2019, and the majority were white (87% vs. 69%). Government-sponsored insurance was more prevalent in both groups (62% vs. 66%). HI had a higher percentage of uninsured individuals (8% vs. 5% NH) (p-value=0.01). The median income bracket was over $46,000 for both cohorts, HI 34% and NH 37%. Advanced comorbidities were similar between HI 50% and NH 43% based on Charlson-Deyo Score. The survival probabilities at 2, 5, and 10 years for HI vs NH were (40% vs 40%), (34% vs 289%), and (34% vs 24%), respectively. The median survival time (MS) was 0.8 years for HI and 0.9 years for NH. There was no overall survival (OS) difference (p-value=0.51). On multivariate analysis, there were no independent variables associated with better or worse OS. The propensity-matched analysis showed no MS difference between HI and NH (0.80 vs 0.71 years). Conclusion: This hospital-based analysis confirmed low survival rates and revealed no statistical differences in MS or OS among HI and NH individuals with PEL. Interestingly, the disease was more prevalent in high-income subjects in both cohorts, despite HI individuals having lower insurance rates. A better understanding of intrinsic disease characteristics and biological variables can offer valuable insights into how to unveil potential targets of better and hopefully meaningful therapies that could improve survival outcomes. Citation Format: Sergio A. Vallejo Avila, Joel Michalek, Qianquian Liu, Adolfo E. Diaz Duque. Contemporary hospital-based study examining demographics, treatment patterns and survival outcomes of primary effusion lymphoma in the United States, with a specific emphasis on Hispanics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4857.

Outcomes in Kaposi's sarcoma-associated herpesvirus -associated primary effusion lymphoma and multicentric Castleman's disease in patients with human immunodeficiency virus (HIV) in a safety-net hospital system.

To describe cases of Kaposi's sarcoma-associated herpesvirus (KSHV)-associated multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL) in patients with HIV from a large, safety-net hospital system in Dallas, Texas, USA. We conducted a retrospective review of patients with HIV-associated PEL and/or MCD. Twelve patients with PEL and 10 patients with MCD were identified. All patients were male and 17 of 20 were men who have sex with men; 66.7% of PEL patients and 50% of MCD patients had concurrent KS at the time of diagnosis; 42% of patients with PEL and 20% of patients with MCD died during the follow-up period. We noted improved survival in our cohort compared to previous studies, particularly in our PEL patients with a median survival of 11.4 months compared to 3-6-month median survival historically. Median follow-up time for MCD patients was 17.5 months. This improved survival is despite suboptimal antiretroviral therapy (ART) adherence at diagnosis, with only 50% of patients on ART at the time of MCD/PEL diagnosis. These data highlight the importance of early recognition of PEL and MCD, and the larger-scale efforts needed to better understand the pathogenetic drivers of clinical outcomes in patients affected by KSHV-related diseases.

Application of the CDK9 inhibitor FIT-039 for the treatment of KSHV-associated malignancy

Chronic infection with Kaposi’s sarcoma-associated herpes virus (KSHV) in B lymphocytes causes primary effusion lymphoma (PEL), the most aggressive form of KSHV-related cancer, which is resistant to conventional chemotherapy. In this study, we report that the BCBL-1 KSHV+ PEL cell line does not harbor oncogenic mutations responsible for its aggressive malignancy. Assuming that KSHV viral oncogenes play crucial roles in PEL proliferation, we examined the effect of cyclin-dependent kinase 9 (CDK9) inhibitor FIT-039 on KSHV viral gene expression and KSHV+ PEL proliferation. We found that FIT-039 treatment impaired the proliferation of KSHV+ PEL cells and the expression of KSHV viral genes in vitro. The effects of FIT-039 treatment on PEL cells were further evaluated in the PEL xenograft model that retains a more physiological environment for the growth of PEL growth and KSHV propagation, and we confirmed that FIT-039 administration drastically inhibited PEL growth in vivo. Our current study indicates that FIT-039 is a potential new anticancer drug targeting KSHV for PEL patients.

ABCL-062: Primary Effusion Lymphoma: Clinical Characteristics and Natural History

<h3>Introduction</h3> Primary effusion lymphoma (PEL) is a very rare type of non-Hodgkin lymphoma (NHL), accounting for less than 4% of HIV-related NHL and frequently occurring in the context of HIV or other states of immunosuppression infection. Large-scale studies describing the natural history of this entity are lacking. <h3>Materials and Methods</h3> The National Cancer Database (NCDB) was queried for patients diagnosed with PEL between 2004 and 2017. All patients aged ≥18 years diagnosed with PEL were included. We excluded patients with multiple primary malignancies or lost to follow-up. Kaplan-Meier and multivariate Cox regression were used in the analyses. <h3>Results</h3> Of the 219 PEL patients included in the analysis, 179 (82%) were males, 161 (74%) Caucasian, and 49 (22%) African American. The median age at diagnosis was 60±19 years. One hundred fifteen (53%) were HIV-positive, and 63 (29%) HIV-negative. One hundred eleven (51%) received chemotherapy; 101 (46%) did not receive chemotherapy. The time to treat (TTT) from diagnosis to chemotherapy start was ≤8 days in 27 patients, within 9–15 days in 24 patients, within 16–32 days in 24 patients, and ≥32 days in 25 patients. The median OS for each group was 6 months, 13 months, 41 months, and 16 months, respectively, and the differences were not statistically significant. Compared to HIV-negative patients, HIV-positive patients were younger (mean age 47 <i>vs</i> 77 years, P<0.001), with no significant difference in the stage or IPI score and had better OS (median OS 13 <i>vs</i> 8 months, P=0.015). Patients who received chemotherapy had better OS compared to patients who did not receive chemotherapy (median OS 13 <i>vs</i> 3 months, P<0.001) and that was found in HIV-positive patients (median OS 22.97 <i>vs</i> 1.97 months, P=0.006), but not in HIV-negative patients (median OS 6 <i>vs</i> 8 months, P=0.752). By multivariate analysis, chemotherapy was associated with better OS (HR 0.502, 95% CI 0.324–0.777; P=0.002), whereas HIV status did not affect the OS (HR 0.6, 95% CI 0.3–1.4; P=0.258). <h3>Conclusions</h3> In contrast to the impression that HIV positivity might confer poorer outcomes, these data suggest that HIV-positive patients with PEL have comparable outcomes to HIV-negative patients, possibly due to improvement in antiretroviral therapy.

Arsenic Trioxide and Lenalidomide: A Promising Combination Therapy for Primary Effusion Lymphoma

Primary Effusion Lymphoma (PEL) is an aggressive malignancy caused by the Kaposi sarcoma associated herpesvirus (KSHV). PEL patients rarely respond to conventional chemotherapy and their prognosis is poor, with a median survival of less than six months. The most promising treatment strategies in these patients combine anti-viral treatments with new agents including chemicals and cytokines. Here, we investigated the efficacy of lenalidomide (Lena), an immune modulator with significant clinical activity in a large number of hematological malignancies, and arsenic trioxide (As), a potent agent in acute promyelocytic leukemia and HTLV-I associated adult T cell leukemia.We used three PEL cell lines (BC-1, BC-3 and BCBL-1 which are KSHV+/EBV- malignant B cells derived from PEL patients) and one PEL-negative control cell line (RAJI as a KSHV- malignant B cell line). We demonstrate that the combination of As and Lena resulted in growth inhibition in BC-1 and BC-3 cells and to a lesser degree in BCBL-1 cells while no effect was observed in RAJI cells. This growth arrest was associated with induction of massive apoptosis and a substantial upregulation of phosphorylated and total p53 protein levels. Furthermore, As/Lena inhibited the expression of latent viral transcripts (LANA-1, LANA-2, v-FLIP and v-Cyclin) and proteins (LANA-1/LANA-2) in all tested PEL cells.Finally, and while Lena alone did not have any inhibitory effect on in vitro treated PEL cells, single agent Lena treatment doubled survival of BC-3 PEL mice and significantly prolonged survival in 75% of BCBL-1 PEL mice and led to cure of the remaining 25%. More importantly, combination of As and Lena was highly synergistic and cured 25% and 75% of BC-3 and BCBL-1 PEL mice respectively. These results provide a rational for the therapeutic use of the combination As/Lena in PEL patients. DisclosuresNo relevant conflicts of interest to declare.

Capsaicin Induces ATF4 Translation with Upregulation of CHOP, GADD34 and PUMA.

Primary Effusion Lymphoma (PEL) is a rare and aggressive B-lymphoma caused by Kaposi's sarcoma-associated herpes virus (KSHV) infection that occurs in immunocompromised patients. PEL patients have a poor prognosis. KSHV modulates various cellular signaling pathways to maintain latent infection, and causes malignant conversion of host cells. We previously reported that capsaicin suppressed extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) signaling and induced apoptosis in PEL. Generally, cellular stress such as nutrient starvation, oxidation and virus infection induce CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP) expression by activating transcription factor 4 (ATF4), however endoplasmic reticulum (ER) stress induces CHOP expression by both ATF4 and ATF6. CHOP is associated with apoptosis induction and upregulates growth arrest and DNA damage-inducible protein 34 (GADD34) and p53 up-regulated modulator of apoptosis (PUMA) mRNA expression. In this study, we found a new mechanism in which capsaicin induces apoptosis via ATF4-CHOP-PUMA. Capsaicin promoted transcriptional activation of CHOP, which increased mRNA expression of GADD34 and PUMA, resulting in PEL apoptosis. Furthermore, capsaicin increased ATF4 protein levels by promoting ATF4 translation, not transcription, and had no effect on ATF6-dependent transcriptional activation. In sum, capsaicin promotes ATF4 translation and transcriptional induction of CHOP, which results in PUMA expression and apoptosis in PEL cells.

Remission of an HHV8-related extracavitary primary effusion lymphoma in an HIV-positive patient during antiretroviral treatment containing dolutegravir

BackgroundHuman herpes virus 8 (HHV8) is the causative agent of Kaposi’s sarcoma and has been associated with an increasing number of hematologic diseases such as primary effusion lymphoma (PEL) (both classic and extracavitary form), multicentric Castleman disease and the germinotropic lymphoproliferative disorder. PEL is a rare B cell non-Hodgkin lymphoma that primarily affects immunocompromised patients; aggressive chemotherapy and antiretroviral therapy (ART) with protease inhibitors have been used, with poor results. We present a case of extracavitary PEL in an HIV-infected patient, regressed after ART initiation.Case presentationA 42-year-old male was admitted to the emergency room because of several months of malaise, fever and progressive deterioration of the general conditions. On physical examination soft non-painful subcutaneous masses were palpable at retronuchal, retroauricolar and thoracic regions. HIV serology resulted positive: HIV plasma viremia was 782,270 copies/mL, CD4 103 cells/mL. The excision of one of the masses, metabolically active at a positron emission tomography (PET-CT) scan, revealed an HHV8-related extracavitary PEL. HHV8 plasma viremia was 44,826 copies/mL. ART with tenofovir alafenamide/emtricitabine/dolutegravir was started together with ganciclovir for cytomegalovirus chorioretinitis. The progressive disappearance of the masses was seen after 6 weeks of ART, and a PET-CT scan resulted completely negative at 3 months. After 19 months of ART the patient was in remission of PEL, HIV viremia was undetectable (< 20 copies/mL), CD4 count was 766 cells/mL and HHV8 viremia was undetectable.ConclusionsIn this clinical case, the complete regression of PEL has been achieved after the immune recovery, as a consequence of ART introduction, without chemotherapy. It cannot be excluded that ganciclovir, used for the treatment of CMV chorioretinitis, may have contributed to the control of HHV8 replication. Whether to try or not a conservative approach in HIV-infected PEL patients must be carefully evaluated, considering the patient’s characteristics and the prognostic factors.

Replication Machinery of Kaposi's Sarcoma-associated Herpesvirus and Drug Discovery Research

Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and Castleman's disease. While liposomal doxorubicin has been used as an effective treatment for KS patients, the cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) regimen used for PEL patients was reported to have 1-year survival rates of less than 40%. Moreover, the development of anti-KSHV drugs inhibiting viral replication has been delayed. KSHV establishes a lifelong infection in its host and alternates between a "latent infection" and "lytic infection" state. Latent infection is associated with maintenance of the viral genome and transformation of the infected cells. Lytic infection is the process of producing infectious virus. Elucidating the KSHV life cycle and viral replication machinery is essential for developing novel therapeutic approaches and identifying potential drug targets. To tackle these issues, we have been screening for anti-PEL compounds using PEL-derived cell lines and utilizing recombinant KSHV for functional analysis of KSHV coding genes. In particular, we have focused on the "viral pre-initiation complex" of KSHV and determined its molecular mechanism. The coding proteins conserved among β- and γ-herpesviruses form a complex, which has functional homology with the pre-initiation complex of host cells. The complex is indispensable for the expression of viral proteins composing virus particles. This review summarizes the pathogenesis and therapies of KSHV-associated malignancies. Furthermore, we introduce our recent data on KSHV ORF34, which contributes to viral late gene expression via the formation of the viral pre-initiation complex.

SLAMF7 in Primary Effusion Lymphoma, Target for Individualized Therapy?

Primary effusion lymphoma (PEL) is a rare, aggressive form of B-cell lymphoma. With a median survival time of around six months the prognosis for PEL patients is poor. Therefore, there is a medical need for novel therapeutic strategies.We performed expression array analysis to find potential targets for antibody-based therapy. Unsupervised clustering analysis revealed that PEL cell lines grouped separate from cell lines derived from other B-non Hodgkin lymphoma (B-NHL) entities. Notably, PEL and Hodgkin Lymphoma (HL) cell lines clustered on one arm, separate from all cell lines representing less-differentiated B-NHL variants.PEL and HL cell lines were characterized by a set of common up- and downregulated genes. Typical for PEL and HL was the expression of CCND2 and the absence of Brutons tyrosine kinase and of B-cell markers including CD19, CD20, CD79A and CD79B.Highly expressed in PEL - but not in HL - were CD138, IL-10, SLAMF7 and PRDM1. PRDM1/BLIMP1 is a master regulator of terminal B-cell differentiation. Originally described as repressor, BLIMP1 can also enhance transcription of SLAMF7 in multiple myeloma (MM) and of IL-10 in type 1 regulatory T-cells. Thus, coexpression of the three genes suggests a causal relationship between transcriptionally active PRDM1/BLIMP1 and its targets SLAMF7 and IL-10 also in PEL.Expression of SLAMF7 in PEL is especially noteworthy because a monoclonal antibody targeting SLAMF7 (elotuzumab) has been approved for treatment of patients with MM. We observed that SLAMF7 is comparably expressed in PEL and in MM cell lines. If the results on cell lines can be translated to primary PEL, i.e. if PEL tumor cells express SLAMF7, the patients might benefit from an antibody-based targeted therapy against this antigen. DisclosuresNo relevant conflicts of interest to declare.

Human Herpesvirus 8 and Lymphoproliferative Disorders.

The spectrum of lymphoproliferative disorders linked to human herpesvirus 8 (HHV-8) infection has constantly been increasing since the discovery of its first etiologic association with primary effusion lymphoma (PEL). PEL is a rapidly progressing non-Hodgkin’s B-cell lymphoma that develops in body cavities in an effusional form. With the increase in the overall survival of PEL patients, as well as the introduction of HHV-8 surveillance in immunocompromised patients, the extracavitary, solid counterpart of PEL was later identified. Moreover, virtually all plasmablastic variants of multicentric Castleman’s disease (MCD) developing in HIV-1-infected individuals harbor HHV-8, providing a strong etiologic link between MCD and this oncogenic herpesvirus. Two other pathologic conditions develop in HIV-1-infected persons concomitantly with MCD: MCD with plasmablastic clusters and HHV-8-positive diffuse large B-cell lymphoma not otherwise specified (HHV-8+ DLBCL NOS), the first likely representing an intermediate stage preceding the full neoplastic form. MCD in leukemic phase has also been described, albeit much less commonly. The germinotropic lymphoproliferative disorder (GLPD) may resemble extracavitary PEL, but develops in immune competent HHV8-infected individuals, and, unlike the other disorders, it responds well to conventional therapies. Almost all HHV-8-mediated lymphoproliferative disorders are the result of an interaction between HHV-8 infection and a dysregulated immunological system, leading to the formation of inflammatory niches in which B cells, at different developmental stages, are infected, proliferate and may eventually shift from a polyclonal state to a monoclonal/neoplastic disorder. Herein, we describe the association between HHV-8 and lymphoproliferative disorders and highlight the predominant distinctive features of each disease.

Abstract B019: Developing new ceramide analogs against AIDS-related lymphoma

Abstract The Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiologic agent of several human cancers, including primary effusion lymphoma (PEL), a subtype of highly aggressive non-Hodgkin lymphoma (NHL). PEL preferentially arises in immunocompromised patients, e.g., AIDS patients, but lacks of effective therapeutic options. Ceramide serves as a central mediator in sphingolipid metabolism and is referred to as a “tumor suppressor lipid”; however, its functional role in PEL survival and therapeutic value remain largely unknown. Our previous work demonstrated that targeting sphingolipid metabolism by either sphingosine kinase 2 (SphK2) inhibitor or exogenous ceramides induced significant PEL apoptosis and suppressed tumor progression. Recently, we have synthesized a series of new ceramide analogs with better stability and solubility. Our first screening indicated that at least 2 new compounds effectively inhibited PEL cell growth, through the complex mechanisms including induction of tumor cell apoptosis, cell cycle arrest, intracellular ceramide production, and viral lytic gene expression. By using an immunodeficiency mice xenograft model, we found that these selective ceramide analogs significantly repressed PEL progression in vivo. Ongoing work includes the identification of global gene profile affected by these new compounds within PEL cells using the NGS technology. We hope these new ceramide analogs can be developed as promising therapeutic strategies for prolonging the survival time of PEL patients and/or improving their life quality. Citation Format: Lu Dai, Maryam Foroozesh, Zhiqiang Qin. Developing new ceramide analogs against AIDS-related lymphoma [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B019.

Antitumor activity of the synthetic retinoid ST1926 on primary effusion lymphoma in vitro and in vivo models.

Primary effusion lymphoma (PEL) is a rare B-cell neoplasm, associated with Kaposi sarcoma-associated herpes virus/human herpes virus-8 (KSHV/HHV-8), arising as malignant effusions in body cavities. PEL cells do not harbor conventional genetic cancer mutations; however, their oncogenesis is mainly attributed to HHV-8 latent genes. Treatment strategies are inefficient resulting in poor prognosis of PEL patients, stressing the need for new effective therapy. ST1926 is a synthetic retinoid with favorable antitumor properties and no cross-resistance with the natural retinoid, all-trans retinoic acid. ST1926 has shown potent apoptotic activities on a variety of solid tumors and hematologic malignancies in invitro and invivo models. In the present study we elucidated the antitumor activities and underlying molecular mechanism of ST1926 using invitro, exvivo, and invivo PEL preclinical models. ST1926, at sub‑micromolar concentrations, displayed potent antiproliferative effects on PEL cell lines and malignant ascites. Furthermore, ST1926 treatment of PEL cells and ascites resulted in their accumulation in the sub-G1region, Sphase cell cycle arrest, early DNA damage, PARP cleavage and p53 activation including the upregulation of its target genes p21 and Bax. However, ST1926 did not significantly modulate HHV-8 latent viral transcripts. Importantly, ST1926 delayed formation of ascites and enhanced survival of PEL mice. These results highlight the therapeutic potential of ST1926 in combination with drugs that target HHV-8 in PEL patients.

Clinicopathological characteristics compared between primary effusion lymphoma and human herpesvirus 8 (HHV8)-unrelated primary effusion lymphoma-like lymphoma.

e19024 Background: Primary effusion lymphoma (PEL) and human herpesvirus 8 (HHV8)-unrelated primary effusion lymphoma-like lymphoma (PEL-LL) are among the most rare subtypes of non-Hodgkin B-cell lymphoma. Although a few number of case reports and small case series have suggested a better outcome of PEL-LL compared to PEL, systematic comparison of prognosis between PEL and PEL-LL has never been conducted owing to their rare incidence. Methods: We consecutively collected PEL and PEL-LL patients diagnosed between 2000 and 2016 in 10 institutions in South Korea. All patients were cytogically confirmed and received systemic evaluation to exclude detectable tumor formation. Clinicopathological characteristics and prognosis were compared. Results: A total of 12 PEL and 4 PEL-LL cases were analyzed. Median age at diagnosis was 68.5 (range, 40-88) and 68.5 (range, 59-77) for PEL and PEL-LL, respectively. Male-to-female ratio was 7:5 and 3:1 in each group. Pleural effusion was the most common presentation in both groups. One patient in PEL-LL group presented with vitreous fluid containing lymphoma cells. Seven and two PEL patients were treated with CHOP and CVP-based chemotherapy, respectively and 3 did not receive chemotherapy due to poor performance. Three PEL-LL patients were treated with R-CHOP and the remaining 1 patient with malignant vitreous fluid received high dose methotrexate. One PEL patient received autologous hematopoietic stem cell transplantation after second remission and lived over 14 years thereafter. With estimated median follow-up duration of 99.6 and 20.7 months for PEL and PEL-LL respectively, 3 and 1 death occurred during the entire period in each group. Median overall survival was 119.6 and 66.5 months in PEL and PEL-LL group respectively without statistically significant difference. Conclusions: In our study, long-term prognosis of PEL and PEL-LL showed no difference. This result might be attributed to 2 remarkably long-lived patients in PEL group (longer than 174 and 123 months, respectively) and low statistical power owing to the small sample size.

SIRT1 and AMPK pathways are essential for the proliferation and survival of primary effusion lymphoma cells.

Primary effusion lymphoma (PEL) is a rare and aggressive B-cell lymphoma with a dismal prognosis caused by infection of Kaposi's sarcoma-associated herpesvirus. Despite the findings that numerous viral genes and cellular pathways are essential for the proliferation and survival of PEL cells, there is currently no effective therapeutic treatment for PEL. Here, we report that the metabolic sensor SIRT1 is functionally required for sustaining the proliferation and survival of PEL cells. Knockdown of SIRT1 with specific shRNAs or inhibition of SIRT1 with an inhibitor (tenovin-6) induced cell cycle arrest and apoptosis in PEL cells. We detected high levels of AMPK activation in PEL cells, reflected in AMPKα1 phosphorylation at T174. Knockdown or inhibition of SIRT1 reduced AMPK activation, indicating that SIRT1 was required for AMPK activation. Interestingly, knockdown of AMPK with specific shRNAs or inhibition of AMPK with the inhibitor compound C recapitulated the phenotype of SIRT1, and induced cell cycle arrest and apoptosis, whereas overexpression of a constitutively active AMPK construct rescued the cytotoxic effect of SIRT1 knockdown. Remarkably, treatment with tenovin-6 effectively inhibited the initiation and progression of PEL, and significantly extended the survival of mice in a murine PEL model. Taken together, these results illustrate that the SIRT1-AMPK axis is essential for maintaining the proliferation and survival of PEL and identify SIRT1 and AMPK as potential therapeutic targets, and tenovin-6 as a candidate therapeutic agent for PEL patients. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Targeting HGF/c-MET induces cell cycle arrest, DNA damage, and apoptosis for primary effusion lymphoma

AbstractKaposi sarcoma–associated herpesvirus (KSHV) is a principal causative agent of primary effusion lymphoma (PEL) with a poor prognosis in immunocompromised patients. However, it still lacks effective treatment which urgently requires the identification of novel therapeutic targets for PEL. Here, we report that the hepatocyte growth factor (HGF)/c-MET pathway is highly activated by KSHV in vitro and in vivo. The selective c-MET inhibitor, PF-2341066, can induce PEL apoptosis through cell cycle arrest and DNA damage, and suppress tumor progression in a xenograft murine model. By using microarray analysis, we identify many novel genes that are potentially controlled by HGF/c-MET within PEL cells. One of the downstream candidates, ribonucleoside-diphosphate reductase subunit M2 (RRM2), also displays the promising therapeutic value for PEL treatment. Our findings provide the framework for development of HGF/c-MET–focused therapy and implementation of clinical trials for PEL patients.

Manipulating Host Signaling for Pathogenic Purposes: Hijacking of the Transcriptional Activity of the Host Protein Nrf2 by Kaposi’s Sarcoma-Associated Herpesvirus

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiological agent of two highly aggressive AIDS-related malignancies, endothelial Kaposi’s sarcoma (KS) and B cell primary effusion lymphoma (PEL). Although current antiretroviral therapy (ART) methods have decreased the overall morbidity and mortality in immunocompromised and AIDS patients, KS and PEL remain difficult to treat. Thus, novel therapeutic methods are essential to significantly improve the life expectancy and quality of life of PEL and KS patients, respectively. One of the signaling pathways that is highly modulated during KSHV infection is oxidative stress, which is a well-known inducer of the transcription factor Nrf2. Because Nrf2 plays an important role in the biology of several viral infections, and is an important agent in cancer progression and chemotherapeutic resistance, we recently undertook a study to investigate its role in KSHV infection of endothelial cells. Here, we provide important highlights of our recent findings, including the importance of oxidative stress and PKCζ in Nrf2 activation, a newly discovered feed-forward loop between Nrf2 and COX-2, and the impact of Nrf2 activation on host and KSHV gene expression and pathogenesis. Lastly, we provide insights on the potential therapeutic implications of Nrf2 modulation in KSHV and other virus-associated pathologies.

SUV Max Reduction Criteria of Interim Positron Emission Tomography Improves Prognostic Value in Diffuse Large B-Cell Lymphoma: A Single-Center Retrospective Review

Background: A consensus is yet to be reached on therole of interim fluorine-18 fluorodeoxyglucose (18F-FDG) position emission tomography-computed tomography (PET-CT) for prognosis in diffuse large B-cell lymphoma (DLBCL), but it has been recently reported that maximum standardized uptake value (SUV max) reduction between baseline and midtherapy may be a better predictor of overall survival (OS) and event free survival (EFS).Patients and Method: 456 patients were newly diagnosed with DLBCL in our institute between February 2007 and January 2013. Primary central nervous system lymphoma or primary effusion lymphoma patients were excluded from this study. All patients who were not perfomed PET were also excluded. In order to determine the predictive value of interim PET-CT and SUV max reduction criteria on OS and EFS for patients with DLBCL, we retrospectively analyzed the PET-CT and SUV max data of 104 first-line DLBCL patients treated with 6 to 8 courses of R-CHOP or R-THPCOP therapy.PET-CT was performed at diagnosis (baseline), and after 2 to 4 courses (interim PET). Interim PET was scheduled two weeks after the second to fourth cycle of immunochemotherapy. A visual analysis of interim PET was done with the use of the Deauville criteria, and an analysis of the SUV max reduction criteria was calculated by [(SUV max reduction from baseline to interim PET)/SUV max at baseline]. For each PET image, the tumor with the most intense 18F-FDG uptake was identified among all foci with the use of a graded color scale. The hottest volumetric region was determined, and the SUV max was calculated. To assess the SUV max, the hottest tumor in any region or organ on interim PET was used for comparison, even if its location differed from the initial hottest tumor in baseline PET.Survival curves were estimated with Kaplan–Meier analysis and compared using the log-rank test.Results: One hundred and four patients were enrolled in this study, and their characteristics are detailed in Table 1. With a median follow-up of 38.5 months, the two-year overall survival and EFS were 83.3% and 73.6%. The results forinterim PET were 66.3% (69/104) negative and 33.7% (35/104) positive, respectively.Interim PET negative versus positive two-year OS was 85.0% (95%CI 0.739-0.917) versus 79.9% (95%CI 0.624-0.899) (P value 0.58), and the two-year EFS was 77.7% (95%CI 0.658-0.860) versus 65.7% (0.476-0.789) (P value 0.24), respectively (Figure 1).The SUV max cutoff values 66% estimated by receiver-operating-characteristic (ROC) analysis to distinguish treatment response were similar to other independent cohort studies at 2 to 4 cycles of induction treatment, and this threshold was chosen to analyze our series.For SUV max data, the two-year OS was 84.4% (95%CI 0.750-0.904) for a SUV max reduction ≥66.0% compared with 75.0% (95%CI 0.408-0.912) for a reduction of <66.0% (P value 0.02). The two-year EFS for the former was 75.7% (95%CI 0.654-0.833) compared with 58.3% (95%CI 0.270-0.801) for the latter (P value 0.03) (Figure 2). Baseline characteristics according to SUV max reduction criteria [SUV max≥66%(n=92),and SUV max<66%(n=12)] are summarized in Table 1.Conclusions: Analysis of the data in our study was unable to demonstrate the predictive value of interim PET for OS and EFS, but SUV max reduction criteria may improve the prognostic value of interim PET. However, the 66% cutoff value must be validated in a larger-scale prospective trial, and further investigation and the standardization of SUV max reduction criteria are needed. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Synergistic Preclinical Activity of Bortezomib with Suberoylanilide Hydroxamic Acid (SAHA) in Primary Effusion Lymphoma (PEL)

Abstract 1650Primary effusion lymphoma (PEL) is an aggressive subtype of non-Hodgkin lymphoma typically presenting as effusions in the serous body cavities without a contiguous tumor mass. PEL may develop in elderly immunosuppressed HIV-negative individuals but more commonly affects HIV-positive patients, accounting for 4% of all lymphomas in this population. Kaposi’s sarcoma-associated herpesvirus (KSHV) is directly implicated in the pathogenesis of PEL, however in most patients the malignant B cells are also coinfected with Epstein-Barr virus which may facilitate transformation. Current chemotherapeutic approaches result in dismal outcome of PEL patients with a median survival of only 6 months. Consequently, development of new therapeutic approaches is urgently needed. Recently we reported development of the UM-PEL1 direct xenograft mice model reproducing human PEL (Sarosiek, PNAS 2010) in which bortezomib (BORT) induced virus lytic reactivation leading to malignant B cell death and transient remission of the PEL in vivo. Further improvement on this monotherapy is warranted. Recent studies have shown that suberoylanilide hydroxamic acid (SAHA), a histone deacetylase (HDAC) inhibitor is a highly effective viral lytic-cycle inducer. As herpesviruses are dependent on the proteasome for replication and mature viral production, induction of lytic replication with concomitant inhibition of the proteasome may provide a highly targeted strategy for eradicating KSHV infected cells without leading to increased viremia. Consequently, we hypothesized that combining BORT with SAHA may act synergistically in PEL tumors. Incubation of human PEL cell lines, UM-PEL1, BC1, BC3 and BC5 with BORT-SAHA resulted in increased apoptotis compared to individual treatment with BORT or SAHA, as assayed by flow cytometry using YO-PRO/PI staining. Concordantly, a statistically significant decrease in UM-PEL1 cell proliferation and viability, as examined by an MTT assay, was observed at 48 and 72 hours following combination therapy as compared to untreated cells or cells treated individually with BORT or SAHA. Cell cycle analysis demonstrated that BORT-SAHA combination induced more pronounced G1 cell cycle arrest and apoptosis as compared to individual treatments. SAHA induced a more robust KSHV lytic reactivation compared to BORT. Intriguingly, the BORT-SAHA combination led to an increased expression of the master lytic transactivator RTA and thymidine kinase, however the late lytic gene, K8.1, showed reduced mRNA expression relative to the individual SAHA treatment. These findings were further confirmed by immunofluorescence staining of the K8.1 protein suggesting that BORT could inhibit mature virion production in lytically reactivated malignant B-cells. To comprehensively examine the activity of the BORT-SAHA combination compared to individual BORT or SAHA treatments in vivo, we used UM-PEL1 direct xenograft model. Mice receiving intraperitoneal BORT-SAHA combination showed statistically significant prolonged survival compared to all the control treatments (p<0.001). Since PEL cells are known to be highly dependent on NF-κB for survival, we examined whether the apoptosis induced by the combination treatment was due to the inhibition of this pro-survival pathway. In contrast to our previous observations that individual BORT treatment did not alter NF-κB activity, the in vivo addition of SAHA led to NF-κB inhibition as demonstrated by gel shift assay. Moreover, Western blotting demonstrated downregulation of anti-apoptotic genes, upregulation of pro-apoptotic genes along with the rise in the p53, p21 and increased acetylation of histone 3 in the combination treated mice versus BORT alone. Further, RTA and early lytic gene expression confirmed our in vitro findings that KSHV lytic reactivation is enhanced in the BORT-SAHA treated mice compared to individual treatments. However, transcription of all late lytic genes tested (gB, K8.1, gM, ORF38, ORF67, ORF68) was uniformly inhibited in the animals treated with the BORT-SAHA as compared to SAHA alone, suggesting that the virus was unable to complete the full replicative cycle. In conclusion, this study demonstrates strong pre-clinical activity of the combination of proteasome inhibitor with HDAC inhibitor as a potent anti-PEL therapy that triggers apoptosis by prompting KSHV lytic reactivation without increasing infectious virus production. Disclosures:No relevant conflicts of interest to declare.

Elevation of clonal serum free light chains in patients with HIV-negative primary effusion lymphoma (PEL) and PEL-like lymphoma

Elevation of clonal serum free light chains in patients with HIV-negative primary effusion lymphoma (PEL) and PEL-like lymphoma

胃に小病変をともない，腹腔のprimary effusion lymphoma類似の臨床像にて発症した非ホジキン悪性リンパ腫の1例

胃に小病変をともない，腹腔のprimary effusion lymphoma類似の臨床像にて発症した非ホジキン悪性リンパ腫の1例