Bortezomib inhibits proteasomal degradation of IκBα and induces mitochondrial dependent apoptosis in activated B-cell diffuse large B-cell lymphoma

Factors determining the sensitivity to proteasome inhibitors of multiple myeloma cells

Multiple myeloma is an incurable cancer that originates from antibody-producing plasma cells. It is characterized by an intrinsic ability to produce large amounts of immunoglobulin-like proteins. The high rate of synthesis makes myeloma cells dependent on protein processing mechanisms related to the proteasome. This dependence made proteasome inhibitors such as bortezomib and carfilzomib one of the most important classes of drugs used in multiple myeloma treatment. Inhibition of the proteasome is associated with alteration of a number of important biological processes leading, in consequence, to inhibition of angiogenesis. The effect of drugs in this group and the degree of patient response to the treatment used is itself an extremely complex process that depends on many factors. At cellular level the change in sensitivity to proteasome inhibitors may be related to differences in the expression level of proteasome subunits, the degree of proteasome loading, metabolic adaptation, transcriptional or epigenetic factors. These are just some of the possibilities that may influence differences in response to proteasome inhibitors. This review describes the main cellular factors that determine the degree of response to proteasome inhibitor drugs, as well as information on the key role of the proteasome and the performance characteristics of the inhibitors that are the mainstay of multiple myeloma treatment.

FPFT-2216, a Novel Anti-lymphoma Compound, Induces Simultaneous Degradation of IKZF1/3 and CK1α to Activate p53 and Inhibit NFκB Signaling

Reducing casein kinase 1α (CK1α) expression inhibits the growth of multiple cancer cell lines, making it a potential therapeutic target for cancer. Herein, we evaluated the antitumor activity of FPFT-2216-a novel low molecular weight compound-in lymphoid tumors and elucidated its molecular mechanism of action. In addition, we determined whether targeting CK1α with FPFT-2216 is useful for treating hematopoietic malignancies. FPFT-2216 strongly degraded CK1α and IKAROS family zinc finger 1/3 (IKZF1/3) via proteasomal degradation. FPFT-2216 exhibited stronger inhibitory effects on human lymphoma cell proliferation than known thalidomide derivatives and induced upregulation of p53 and its transcriptional targets, namely, p21 and MDM2. Combining FPFT-2216 with an MDM2 inhibitor exhibited synergistic antiproliferative activity and induced rapid tumor regression in immunodeficient mice subcutaneously transplanted with a human lymphoma cell line. Nearly all tumors in mice disappeared after 10 days; this was continuously observed in 5 of 7 mice up to 24 days after the final FPFT-2216 administration. FPFT-2216 also enhanced the antitumor activity of rituximab and showed antitumor activity in a patient-derived diffuse large B-cell lymphoma xenograft model. Furthermore, FPFT-2216 decreased the activity of the CARD11/BCL10/MALT1 (CBM) complex and inhibited IκBα and NFκB phosphorylation. These effects were mediated through CK1α degradation and were stronger than those of known IKZF1/3 degraders. In conclusion, FPFT-2216 inhibits tumor growth by activating the p53 signaling pathway and inhibiting the CBM complex/NFκB pathway via CK1α degradation. Therefore, FPFT-2216 may represent an effective therapeutic agent for hematopoietic malignancies, such as lymphoma.

SIGNIFICANCE

We found potential vulnerability to CK1α degradation in certain lymphoma cells refractory to IKZF1/3 degraders. Targeting CK1α with FPFT-2216 could inhibit the growth of these cells by activating p53 signaling. Our study demonstrates the potential therapeutic application of CK1α degraders, such as FPFT-2216, for treating lymphoma.

Clinical Potential of Fruit in Bladder Cancer Prevention and Treatment

Bladder cancer (BC) is the most common tumor of the urinary system in the world. Moreover, despite using anticancer therapies, BC is also characterized by a high recurrence risk. Among numerous risk factors, cigarette smoking, occupational exposure to certain aromatic compounds, and genetic factors contribute most strongly to BC development. However, the epidemiological data to date suggests that diet quality may influence some carcinogenic factors of BC and, therefore, might have a preventative effect. Adequate consumption of selected fruits with scientifically proven properties, including pomegranates and cranberries, can significantly reduce the risk of developing BC, even in those at risk. Therefore, in this article, we aim to elucidate, using available literature, the role of fruits, including pomegranates, cranberries, citrus fruits, cactus pears, and apples, in BC prevention and treatment. Previous data indicate the role of compounds in the above-mentioned fruits in the modulation of the signaling pathways, including cell proliferation, cell growth, cell survival, and cell death.

Reactive oxygen species (ROS) in cancer pathogenesis and therapy: An update on the role of ROS in anticancer action of benzophenanthridine alkaloids

Reactive oxygen species play crucial role in biological homeostasis and pathogenesis of human diseases including cancer. In this line, now it has become evident that ROS level/concentration is a major factor in the growth, progression and stemness of cancer cells. Moreover, cancer cells maintain a delicate balance between ROS and antioxidants to promote pathogenesis and clinical challenges via targeting a battery of signaling pathways converging to cancer hallmarks. Recent findings also entail the therapeutic importance of ROS for the better clinical outcomes in cancer patients as they induce apoptosis and autophagy. Moreover, poor clinical outcomes associated with cancer therapies are the major challenge and use of natural products have been vital in attenuation of these challenges due to their multitargeting potential with less adverse effects. In fact, most available drugs are derived from natural resources, either directly or indirectly and available evidence show the clinical importance of natural products in the management of various diseases, including cancer. ROS play a critical role in the anticancer actions of natural products, particularly phytochemicals. Benzophenanthridine alkaloids of the benzyl isoquinoline family of alkaloids, such as sanguinarine, possess several pharmacological properties and are thus being studied for the treatment of different human diseases, including cancer. In this article, we review recent findings, on how benzophenanthridine alkaloid-induced ROS play a critical role in the attenuation of pathological changes and stemness features associated with human cancers. In addition, we highlight the role of ROS in benzophenanthridine alkaloid-mediated activation of the signaling pathway associated with cancer cell apoptosis and autophagy.

A three-gene signature based on MYC, BCL-2 and NFKBIA improves risk stratification in diffuse large B-cell lymphoma

Recent randomized trials focused on gene expression-based determination of the cell of origin in diffuse large B-cell lymphoma could not show significant improvements by adding novel agents to standard chemoimmunotherapy. The aim of this study was the identification of a gene signature able to refine current prognostication algorithms and applicable to clinical practice. Here we used a targeted gene expression profiling panel combining the Lymph2Cx signature for cell of origin classification with additional targets including MYC, BCL-2 and NFKBIA, in 186 patients from two randomized trials (discovery cohort) (clinicaltrials gov. Identifier: NCT00355199 and NCT00499018). Data were validated in three independent series (two large public datasets and a real-life cohort). By integrating the cell of origin, MYC/BCL-2 double expressor status and NFKBIA expression, we defined a three-gene signature combining MYC, BCL-2 and NFKBIA (MBN-signature), which outperformed the MYC/BCL-2 double expressor status in multivariate analysis, and allowed further risk stratification within the germinal center B-cell/unclassified subset. The high-risk (MBN Sig-high) subgroup identified the vast majority of double hit cases and a significant fraction of activated B-cell-derived diffuse large B-cell lymphomas. These results were validated in three independent series including a cohort from the REMoDL-B trial, where, in an exploratory ad hoc analysis, the addition of bortezomib in the MBN Sig-high subgroup provided a progression free survival advantage compared with standard chemoimmunotherapy. These data indicate that a simple three-gene signature based on MYC, BCL-2 and NFKBIA could refine the prognostic stratification in diffuse large B-cell lymphoma, and might be the basis for future precision-therapy approaches.

Predictive and Prognostic Molecular Factors in Diffuse Large B-Cell Lymphomas

Diffuse large B-cell lymphoma (DLBCL) is the commonest form of lymphoid malignancy, with a prevalence of about 40% worldwide. Its classification encompasses a common form, also termed as “not otherwise specified” (NOS), and a series of variants, which are rare and at least in part related to viral agents. Over the last two decades, DLBCL-NOS, which accounts for more than 80% of the neoplasms included in the DLBCL chapter, has been the object of an increasing number of molecular studies which have led to the identification of prognostic/predictive factors that are increasingly entering daily practice. In this review, the main achievements obtained by gene expression profiling (with respect to both neoplastic cells and the microenvironment) and next-generation sequencing will be discussed and compared. Only the amalgamation of molecular attributes will lead to the achievement of the long-term goal of using tailored therapies and possibly chemotherapy-free protocols capable of curing most (if not all) patients with minimal or no toxic effects.

Anti-leukemic effects of histone deacetylase (HDAC) inhibition in acute lymphoblastic leukemia (ALL) cells: Shedding light on mitigating effects of NF-κB and autophagy on panobinostat cytotoxicity

Identification of the roles of epigenetic alterations in cancers has suggested that different molecules involved in this process are potentially therapeutic targets. Given the role of histone deacetylases (HDACs) enzymes in leukemogenesis, we designed a study to investigate the anti-leukemic property of panobinostat, a HDAC inhibitor, in acute lymphoblastic leukemia (ALL) cells. Our results showed that panobinostat decreased cell viability of pre-B ALL-derived cells. The favorable anti-leukemic effects of the inhibitor was further confirmed by cell cycle analysis, where we found that panobinostat prolonged the transition of the cells from G1 phase probably through c-Myc-mediated up-regulation of cyclin-dependent kinase inhibitors. Unlike the apoptotic effect of panobinostat on Nalm-6 cells, the expression of anti-apoptotic nuclear factor-kappa B (NF-κB) target genes remained unchanged. Accordingly, we found that the inhibition of NF-κB pathway using bortezomib boosted the effect of panobinostat, indicating that panobinostat-induced apoptosis could be attenuated through the activation of the NF-κB pathway. The results of the present study reflected another aspect of autophagy in leukemic cells, as we showed that although Nalm-6 cells could exploit autophagy to override the anti-survival effect of HDAC inhibition, the presence of an autophagy inhibitor could alter the compensatory circumstance to induce cell death. Beyond panobinostat cytotoxicity as a single agent, synergistic experiments outlined that pharmaceutical targeting of HDACs could amplify the cytotoxicity of vincristine in ALL cells, delineating that panobinostat, either as a single agent or in a combined modality, possesses novel promising potentials for the treatment of ALL.

Front-Line Treatment of High Grade B Cell Non-Hodgkin Lymphoma

PURPOSE OF REVIEW

Rituximab-based chemoimmunotherapy has resulted in a marked improvement in the survival of diffuse large B cell lymphoma (DLBCL). We reflect upon the history front-line (1L) therapy and highlight advances in management.

RECENT FINDINGS

Since the introduction of R-CHOP, the majority of randomized studies in the front-line treatment of DLBCL have failed to show a benefit. Such studies have involved treatment intensification, adding novel agents to the R-CHOP backbone and targeting such novel agents to biologically defined subgroups. R-CHOP therefore remains standard-of-care for most but new insights into the molecular biology of these diseases, and the development of active targeted molecules offers promise for the future. Accumulating evidence in the very elderly suggests dose attenuation does not compromise survival. Intensification in primary mediastinal B cell lymphoma may avoid the need for radiotherapy, but must be balanced against the risks. PET-CT- and ctDNA-based response assessment may now enable response adapted therapy and early prognostication, improving patient selection and potentially outcomes. Novel technologies and therapies in combination with novel molecular diagnostics will likely become the standard-of-care approach for the personalized therapy of DLBCL but need to be proven in well-designed and conducted randomized trials.

Inhibition of the PI3K/AKT signaling pathway sensitizes diffuse large B-cell lymphoma cells to treatment with proteasome inhibitors via suppression of BAG3

Proteasome inhibitors represent a novel class of drugs that have clinical efficacy against hematological and solid cancer types, including acute myeloid leukaemia, myelodysplastic syndrome an non-small cell lung cancer. It has been demonstrated that the anti-apoptotic protein B-cell lymphoma-2-associated athanogene 3 (BAG3) is induced by proteasome inhibitors in various cancer cells and serves an important role in chemotherapy resistance. The phosphatidylinositol 3-kinase (PI3K)/RAC-α serine/threonine-protein kinase (AKT) pathway is constitutively activated in a number of lymphoid malignancy types, including diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma. In the present study, the aim was to elucidate the role of the PI3K/AKT signaling pathway in the induction of BAG3, following exposure to a proteasome inhibitor in DLBCL cell lines. Bortezomib and MG132 were used as proteasome inhibitors. Western blotting was used to evaluate the roles of proteasome inhibitors and the PI3K/AKT pathway in BAG3 induction in DLBCL cells (LY1 and LY8), and LY294002 was used to block the PI3K/AKT pathway. Cell viability was detected using a Cell Counting Kit-8 assay. Apoptosis of LY1 and LY8 cells was quantified by Annexin V/7-amino-actinomycin D flow cytometry. The BAG3 protein was markedly induced upon exposure to bortezomib and MG132 in a dose-dependent manner. The PI3K/AKT inhibitor LY294002 significantly suppressed the induction of BAG3 by proteasome inhibitors. Inhibition of the PI3K/AKT pathway decreased the proliferation and increased the apoptosis induced by proteasome inhibitors. The present results indicated that the PI3K/AKT pathway is associated with the activation of BAG3 expression in DLBCL cells, and is involved in the protective response against proteasome inhibition.

Regulation of Protein Degradation by Proteasomes in Cancer

Imbalance of protein homeostasis (proteostasis) is known to cause cellular malfunction, cell death, and diseases. Elaborate regulation of protein synthesis and degradation is one of the important processes in maintaining normal cellular functions. Protein degradation pathways in eukaryotes are largely divided into proteasome-mediated degradation and lysosome-mediated degradation. Proteasome is a multisubunit complex that selectively degrades 80% to 90% of cellular proteins. Proteasome-mediated degradation can be divided into 26S proteasome (20S proteasome + 19S regulatory particle) and free 20S proteasome degradation. In 1980, it was discovered that during ubiquitination process, wherein ubiquitin binds to a substrate protein in an ATP-dependent manner, ubiquitin acts as a degrading signal to degrade the substrate protein via proteasome. Conversely, 20S proteasome degrades the substrate protein without using ATP or ubiquitin because it recognizes the oxidized and structurally modified hydrophobic patch of the substrate protein. To date, most studies have focused on protein degradation via 26S proteasome. This review describes the 26S/20S proteasomal pathway of protein degradation and discusses the potential of proteasome as therapeutic targets for cancer treatment as well as against diseases caused by abnormalities in the proteolytic system.

AID and TET2 co-operation modulates FANCA expression by active demethylation in diffuse large B cell lymphoma

Diffuse large B cell lymphoma (DLBCL) is traced to a mature B malignance carrying abnormal activation-induced cytidine deaminase (AID) expression. AID activity initially focuses on deamination of cytidine to uracil to generate somatic hypermutation and class-switch recombination of the immunoglobulin (Ig), but recently it has been implicated in DNA demethylation of genes required for B cell development and proliferation in the germinal centre (GC). However, whether AID activity on mutation or demethylation of genes involves oncogenesis of DLBCL has not been well characterized. Our data demonstrate that the proto-oncogene Fanconi anaemia complementation group A (FANCA) is highly expressed in DLBCL patients and cell lines, respectively. AID recruits demethylation enzyme ten eleven translocation family member (TET2) to bind the FANCA promoter. As a result, FANCA is demethylated and its expression increases in DLBCL. On the basis of our findings, we have developed a new therapeutic strategy to significantly inhibit DLBCL cell growth by combination of the proteasome inhibitor bortezomib with AID and TET2 depletion. These findings support a novel mechanism that AID has a crucial role in active demethylation for oncogene activation in DLBCL.

Downregulation of SKP2 in Papillary Thyroid Cancer Acts Synergistically With TRAIL on Inducing Apoptosis via ROS

CONTEXT AND OBJECTIVE

S-phase kinase protein 2 (SKP2) is an F-box protein with proteasomal properties and has been found to be overexpressed in a variety of cancers. However, its role in papillary thyroid cancer (PTC) has not been fully elucidated.

EXPERIMENTAL DESIGN

SKP2 expression was assessed by immunohistochemistry in a tissue microarray format on a cohort of >1000 PTC samples. In vitro and in vivo studies were performed using proteasome inhibitor bortezomib and proapoptopic death ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) either alone or in combination on PTC cell lines.

RESULTS

SKP2 was overexpressed in 45.5% of PTC cases and was significantly associated with extrathyroidal extension (P = 0.0451), distant metastasis (P = 0.0435), and tall cell variant (P = 0.0271). SKP2 overexpression was also directly associated with X-linked inhibitor of apoptosis protein overexpression (P < 0.0001) and Bcl-xL overexpression (P = 0.0005) and inversely associated with death receptor 5 (P < 0.0001). The cotreatment of bortezomib and TRAIL synergistically induced apoptosis via mitochondrial apoptotic pathway in PTC cell lines. Furthermore, bortezomib and TRAIL synergistically induced reactive oxygen species (ROS) generation and caused death receptor 5 upregulation through activation of the extracellular signal-regulated kinase-C/EBP homologous protein signaling cascade. Finally, bortezomib treatment augmented the TRAIL-mediated anticancer effect on PTC xenograft tumor growth in nude mice.

CONCLUSION

These data suggest that SKP2 is a potential therapeutic target in PTC and that a combination of bortezomib and TRAIL might be a viable therapeutic option for the treatment of patients with aggressive PTC.

Prognostic value of expression of nuclear factor kappa-B/p65 in non-GCB DLBCL patients

Purpose

We estimated the expression of nuclear factor kappa B/p65 in non-germinal center B-cell-like subtype diffuse large B-cell lymphoma, to investigate its relationship to clinicopathological features, and to further evaluate its prognostic value and clarify its impact on survival.

Results

Among the 49 patients enrolled in this study, 14 (28.6%) had positive p65 expression. The negative p65 group had significantly better survival compared to the positive p65 group in terms of both the 3-year estimated OS (91.2% vs. 39.3%, p = 0.003) and PFS (75.6% vs. 26.5%, p = 0.002). In patients with 4 or more risk factors, p65 was an independent prognostic factor of OS (HR 5.99, 95%CI=1.39-25.75, p=0.016) and PFS (HR 4.01, 95%CI=1.15-14.00, p=0.029).

Materials and Methods

The expression of the NF-κB/p65 protein was deteremined by immunohistochemistry in 49 non-GCB DLBCL. Survival was assessed by the Kaplan–Meier method and Cox multivariate analysis. The median patient follow-up period was 24 months.

Conclusions

The expression of NF-κB/p65 has prognostic value in high risk non-GCB DLBCL, and it is a suitable target for the development of new therapies.

Wogonin as a targeted therapeutic agent for EBV (+) lymphoma cells involved in LMP1/NF-κB/miR-155/PU.1 pathway

Background

Wogonin is an encouraging choice for clinical use owing to its potent anti-tumor and anti-inflammatory effects with the high safety profile. However, wogonin for targeted therapy of lymphoma was not well addressed. In this study, we focused on its anticancer effect alongside with the underlying mechanisms for targeted therapy in EBV-positive lymphoma. This will facilitate its introduction to clinical use, which is planned in the near future.

Methods

Cell proliferation was studied by CCK8. Flow cytometry was used to analyze the apoptosis and the cycle arrest of cells. Further, we also used immunofluorescent staining to detect the morphologic changes of the apoptotic cells. The expression of LMP1/miR-155/p65/pp65/PU.1 was evaluated by quantitative real-time PCR (qRT-PCR) and western blot, while that of NF-κB was analyzed by EMSA. At last, immunohistochemical staining was applied to assess the expression of target proteins and relevant molecules.

Results

In vitro, wogonin induced the apoptosis of Raji cells by downregulating the expression of NF-κB through LMP1/miR-155/NF-κB/PU.1 pathway, which was in a dose and time-dependent manner. In vivo, wogonin could suppress tumor growth, associated with the downregulation of ki67, p65 and upregulation of PU.1.

Conclusions

Wogonin could suppress tumor growth and induce cell apoptosis by inhibiting the expression of NF-κB. Taken these findings, we concluded that wogonin could be a potential targeted therapeutic agent for EBV-positive lymphoma with the expression of LMP1 through the pathway of LMP1/NF-κB/miR-155/PU.1.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3145-4) contains supplementary material, which is available to authorized users.

A phase II trial evaluating the effects and intra-tumoral penetration of bortezomib in patients with recurrent malignant gliomas

One resistance mechanism in malignant gliomas (MG) involves nuclear factor-κB (NF-κB) activation. Bortezomib prevents proteasomal degradation of NF-κB inhibitor α (NFKBIA), an endogenous regulator of NF-κB signaling, thereby limiting the effects of NF-κB on tumor survival and resistance. A presurgical phase II trial of bortezomib in recurrent MG was performed to determine drug concentration in tumor tissue and effects on NFKBIA. Patients were enrolled after signing an IRB approved informed consent. Treatment was bortezomib 1.7 mg/m(2) IV on days 1, 4 and 8 and then surgery on day 8 or 9. Post-operatively, treatment was Temozolomide (TMZ) 75 mg/m(2) PO on days 1-7 and 14-21 and bortezomib 1.7 mg/m(2) on days 7 and 21 [1 cycle was (1) month]. Ten patients were enrolled (8 M and 2 F) with 9 having surgery. Median age and KPS were 50 (42-64) and 90 % (70-100). The median cycles post-operatively was 2 (0-4). The trial was stopped as no patient had a PFS-6. All patients are deceased. Paired plasma and tumor bortezomib concentration measurements revealed higher drug concentrations in tumor than in plasma; NFKBIA protein levels were similar in drug-treated vs. drug-naïve tumor specimens. Nuclear 20S proteasome was less in postoperative samples. Postoperative treatment with TMZ and bortezomib did not show clinical activity. Bortezomib appears to sequester in tumor but pharmacological effects on NFKBIA were not seen, possibly obscured due to downregulation of NFKBIA during tumor progression. Changes in nuclear 20S could be marker of bortezomib effect on tumor.

Clarification of the molecular pathway of Taiwan local pomegranate fruit juice underlying the inhibition of urinary bladder urothelial carcinoma cell by proteomics strategy

Background

Pomegranate fruit has been shown to exhibit the inhibitory activity against prostate cancer and lung cancer in vitro and in vivo, which might be a resource for chemoprevention and chemotherapy of cancer. Our previous documented findings indicated that treatment of urinary bladder urothelial carcinoma cell with the ethanol extract isolated from the juice of pomegranate fruit grown in Taiwan could inhibit tumor cell. In this study we intended to uncover the molecular pathway underlying anti-cancer efficacy of Taiwan pomegranate fruit juice against urinary bladder urothelial carcinoma.

Methods

We exploited two-dimensional gel electrophoresis coupled with tandem mass spectrometry to find the de-regulated proteins. Western immunoblotting was used to confirm the results collected from proteomics study.

Results

Comparative proteomics indicated that 20 proteins were differentially expressed in ethanol extract-treated T24 cells with 19 up-regulated and 1 down-regulated proteins. These de-regulated proteins were involved in apoptosis, cytoskeleton regulation, cell proliferation, proteasome activity and aerobic glycolysis. Further studies on signaling pathway demonstrated that ethanol extract treatment might inhibit urinary bladder urothelial carcinoma cell proliferation through restriction of PTEN/AKT/mTORC1 pathway via profilin 1 up-regulation. It also might evoke cell apoptosis through Diablo over-expression.

Conclusions

The results of this study provide a global picture to further investigate the anticancer molecular mechanism of pomegranate fruit.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1071-7) contains supplementary material, which is available to authorized users.

Epstein-Barr virus-associated diffuse large B-cell lymphoma: diagnosis, difficulties and therapeutic options

Epstein Barr Virus (EBV)-positive diffuse large B cell lymphoma (DLBCL) most frequently affects elderly patients, without previous immunosuppression, with frequent extra-nodal involvement and whose disease runs an aggressive clinical course with high International Prognostic Index (IPI) scores. Various EBV-related transforming mechanisms, much favored by immunosenescence, have been described, including activation of the NFKB transcriptional program. Elderly patients show poor survival after treatment with conventional CHOP regimens, even after addition of Rituximab. Younger patients, however, have a better outcome with a similar prognosis to EBV-negative DLBCL cases. New therapeutic strategies, including treatments targeting EBV, new drugs directed against specific pathways constitutively activated in these lymphomas, and new specific conjugate antibodies against molecules usually expressed in the tumor cells, such as CD30, are described.

Subtype-specific therapy for DLBCL: are we there yet?

In this issue of Blood, Offner et al report the results of LYM-2034, a phase 2 multinational trial in which 164 patients with nongerminal center B-cell–like diffuse large B-cell lymphoma (non-GCB DLBCL) were randomized to receive rituximab, cyclophosphamide, adriamycin, prednisone, and either vincristine (R-CHOP) or bortezomib (VR-CAP). DLBCL, previously recognized as a single disease entity, represents a heterogeneous group of diseases.

Frontline rituximab, cyclophosphamide, doxorubicin, and prednisone with bortezomib (VR-CAP) or vincristine (R-CHOP) for non-GCB DLBCL

This phase 2 study evaluated whether substituting bortezomib for vincristine in frontline rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) therapy could improve efficacy in non-germinal center B-cell-like diffuse large B-cell lymphoma (non-GCB DLBCL), centrally confirmed by immunohistochemistry (Hans method). In total, 164 patients were randomized 1:1 to receive six 21-day cycles of rituximab 375 mg/m(2), cyclophosphamide 750 mg/m(2), and doxorubicin 50 mg/m(2), all IV day 1, prednisone 100 mg/m(2) orally days 1-5, plus either bortezomib 1.3 mg/m(2) IV days 1, 4, 8, 11 (rituximab, cyclophosphamide, doxorubicin, and prednisone with bortezomib [VR-CAP]; n = 84) or vincristine 1.4 mg/m(2) (maximum 2 mg) IV day 1 (R-CHOP; n = 80). There were no significant differences between VR-CAP and R-CHOP in complete response rate (64.5%, 66.2%; odds ratio [OR], 0.91; P = .80), overall response rate (93.4%, 98.6%; OR, 0.21; P = .11), progression-free survival (hazard ratio [HR], 1.12; P = .76), or overall survival (HR, 0.89; P = .75). Rates of grade ≥3 adverse events (AEs; 88%, 89%), serious AEs (38%, 34%), discontinuations due to AEs (7%, 3%), and deaths due to AEs (2%, 5%) were similar with VR-CAP and R-CHOP. Grade ≥3 peripheral neuropathy rates were 6% and 3%, respectively. VR-CAP did not improve efficacy vs R-CHOP in non-GCB DLBCL. This trial was registered at www.clinicaltrials.gov as #NCT01040871.

Novel targeted therapies in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive non-Hodgkin's lymphoma. Next-generation sequencing techniques have improved our understanding of the molecular pathways that may drive oncogenesis. Many novel classes of drugs are in development that may improve the treatment of DLBCL, either as single agents or in combination, that exploit their synergy to overcome resistance. We review the key novel targets and therapeutics in the treatment of DLBCL, including immunomodulatory agents and immunotherapy.

A comprehensive analysis of the cellular and EBV-specific microRNAome in primary CNS PTLD identifies different patterns among EBV-associated tumors

Primary central nervous system (pCNS) posttransplant lymphoproliferative disorder (PTLD) is a complication of solid organ transplantation characterized by poor outcome. In contrast to systemic PTLD, Epstein-Barr virus (EBV)-association of pCNS PTLD is almost universal, yet viral and cellular data are limited. To identify differences in the pattern of EBV-association of pCNS and systemic PTLD, we analyzed the expression of latent and lytic EBV transcripts and the viral and cellular microRNAome in nine pCNS (eight EBV-associated) and in 16 systemic PTLD samples (eight EBV-associated). Notably although 15/16 EBV-associated samples exhibited a viral type III latency pattern, lytic transcripts were also strongly expressed. Members of the ebv-miR-BHRF1 and ebv-miR-BART clusters were expressed in virtually all EBV-associated PTLD samples. There were 28 cellular microRNAs differentially expressed between systemic and pCNS PTLD. pCNS PTLD expressed lower hsa-miR-199a-5p/3p and hsa-miR-143/145 (implicated in nuclear factor kappa beta and c-myc signaling) as compared to systemic PTLD. Unsupervised nonhierarchical clustering of the viral and cellular microRNAome distinguished non-EBV-associated from EBV-associated samples and identified a separate group of EBV-associated pCNS PTLD that displayed reduced levels of B cell lymphoma associated oncomiRs such as hsa-miR-155, -21, -221 and the hsa-miR-17-92 cluster. EBV has a major impact on viral and cellular microRNA expression in EBV-associated pCNS PTLD.

Bortezomib sensitizes non-small cell lung cancer to mesenchymal stromal cell-delivered inducible caspase-9-mediated cytotoxicity

Delivery of suicide genes to solid tumors represents a promising tumor therapy strategy. However, slow or limited killing by suicide genes and ineffective targeting of the tumor has reduced effectiveness. We have adapted a suicide system based on an inducible caspase-9 (iC9) protein that is activated using a specific chemical inducer of dimerization (CID) for adenoviral-based delivery to lung tumors via mesenchymal stromal cells (MSCs). Four independent human non-small cell lung cancer (NSCLC) cell lines were transduced with adenovirus encoding iC9, and all underwent apoptosis when iC9 was activated by adding CID. However, there was a large variation in the percentage of cell killing induced by CID across the different lines. The least responsive cell lines were sensitized to apoptosis by combined inhibition of the proteasome using bortezomib. These results were extended to an in vivo model using human NSCLC xenografts. E1A-expressing MSCs replicated Ad.iC9 and delivered the virus to lung tumors in SCID mice. Treatment with CID resulted in some reduction of tumor growth, but addition of bortezomib led to greater reduction of tumor size. The enhanced apoptosis and anti-tumor effect of combining MSC-delivered Ad.iC9, CID and bortezomib appears to be due to increased stabilization of active caspase-3, as proteasomal inhibition increased the levels of cleaved caspase-9 and caspase-3. Knockdown of X-linked inhibitor of apoptosis protein (XIAP), a caspase inhibitor that targets active caspase-3 to the proteasome, also sensitized iC9-transduced cells to CID, suggesting that blocking the proteasome counteracts XIAP to permit apoptosis. Thus, MSC-based delivery of the iC9 suicide gene to human NSCLC effectively targets lung cancer cells for elimination. Combining this therapy with bortezomib, a drug that is otherwise inactive in this disease, further enhances the anti-tumor activity of this strategy.