Mantle Cell Lymphoma

Dihydrocelastrol exerts potent antitumor activity in mantle cell lymphoma cells via dual inhibition of mTORC1 and mTORC2

Mantle cell lymphoma (MCL) is a distinct and highly aggressive subtype of B-cell non-Hodgkin lymphoma. Dihydrocelastrol (DHCE) is a dihydro-analog of celastrol, which is isolated from the traditional Chinese medicinal plant Tripterygium wilfordii. The present study aimed to investigate the effects of DHCE treatment on MCL cells, and to determine the mechanism underlying its potent antitumor activity in vitro and in vivo using the Cell Counting kit-8 assay, clonogenic assay, apoptosis assay, cell cycle analysis, immunofluorescence staining, western blotting and tumor xenograft models. The results demonstrated that DHCE treatment exerted minimal cytotoxic effects on normal cells, but markedly suppressed MCL cell proliferation by inducing G0/G1 phase cell cycle arrest, and inhibited MCL cell viability by stimulating apoptosis via extrinsic and intrinsic pathways. In addition, the results revealed that DHCE suppressed cell growth and proliferation by inhibiting mammalian target of rapamycin complex (mTORC)1-mediated phosphorylation of ribosomal protein S6 kinase and eukaryotic initiation factor 4E binding protein. Simultaneously, DHCE induced apoptosis and inhibited cell survival by suppressing mTORC2-mediated phosphorylation of protein kinase B and nuclear factor-κB activity. In addition to in vitro findings, DHCE treatment reduced the MCL tumor burden in a xenograft mouse model, without indications of toxicity. Furthermore, combined treatment with DHCE and bortezomib, a proteasome inhibitor, induced a synergistic cytotoxic effect on MCL cells. These findings indicated that DHCE may have the potential to serve as a novel therapeutic agent for the treatment of MCL through dually inhibiting mTORC1 and mTORC2.

Italian real life experience with ibrutinib: results of a large observational study on 77 relapsed/refractory mantle cell lymphoma

Although sometimes presenting as an indolent lymphoma, mantle cell lymphoma (MCL) is an aggressive disease, hardly curable with standard chemo-immunotherapy. Current approaches have greatly improved patients' outcomes, nevertheless the disease is still characterized by high relapse rates. Before approval by EMA, Italian patients with relapsed/refractory MCL were granted ibrutinib early access through a Named Patient Program (NPP). An observational, retrospective, multicenter study was conducted. Seventy-seven heavily pretreated patients were enrolled. At the end of therapy there were 14 complete responses and 14 partial responses, leading to an overall response rate of 36.4%. At 40 months overall survival was 37.8% and progression free survival was 30%; disease free survival was 78.6% at 4 years: 11/14 patients are in continuous complete response with a median of 36 months of follow up. Hematological toxicities were manageable, and main extra-hematological toxicities were diarrhea (9.4%) and lung infections (9.0%). Overall, 4 (5.2%) atrial fibrillations and 3 (3.9%) hemorrhagic syndromes occurred. In conclusions, thrombocytopenia, diarrhea and lung infections are the relevant adverse events to be clinically focused on; regarding effectiveness, ibrutinib is confirmed to be a valid option for refractory/relapsed MCL also in a clinical setting mimicking the real world.

Time to treatment is an independent prognostic factor in aggressive non-Hodgkin lymphomas

In aggressive lymphomas, discrepancies in survival reported from experimental and observational studies may reflect selective non-enrolment of high-risk patients in trials. We examined the association between time from diagnosis to chemotherapy and overall survival in diffuse large B-cell (DLBCL), Burkitt (BL), mantle cell (MCL) and peripheral T-cell lymphoma (PTCL), using National Cancer Data Base records of 130 549 patients treated in 2004-2014. Across the histologies, patients who started chemotherapy within 7 days of diagnosis had more often high International Prognostic Index (IPI) or advanced-stage disease. The discrepancy in 3-year survival between groups treated within 7 or >30 days from diagnosis ranged from 14% in BL to 30% in MCL. After adjusting for the IPI, time to treatment was significantly associated with shorter overall survival. Using the group treated >30 days from diagnosis as reference, patients treated within 7 days had a hazard ratio of 1·38 [95% confidence interval (CI), 1·28-1·48] in DLBCL, 1·42 (95% CI, 1·22-1·66) in BL, 2·23 (95% CI, 1·79-2·78) in MCL and 1·46 (95% CI, 1·18-1·81) in PTCL. Time from diagnosis to treatment may reflect high-risk features uncaptured by standard prognostic assessments. Clinical trials should accommodate patients who need urgent therapy to improve external validity and detect treatment effects in high-risk groups.

Lipid nanoparticle siRNA cocktails for the treatment of mantle cell lymphoma

Mantle cell lymphoma is an aggressive and incurable subtype of non‐Hodgkin B cell lymphoma. Patients typically present with advanced disease, and most patients succumb within a decade of diagnosis. There is a clear and urgent need for novel therapeutic approaches that will affect mantle cell lymphoma through a unique mechanism compared to current therapies. This study examined the use of RNA interference (RNAi) therapy to attack mantle cell lymphoma at the mRNA level, silencing genes associated with cancer cell proliferation. We identified a lipid nanoparticle formulated with the lipidoid 306O₁₃ that delivered siRNA to JeKo‐1 and MAVER‐1 mantle cell lymphoma cell lines. Three therapeutic gene targets were examined for their effect on lymphoma growth. These included Cyclin D1, which is a cell cycle regulator, as well as Bcl‐2 and Mcl‐1, which prevent apoptosis. Gene knockdown with siRNA doses as low at 10 nM increased lymphoma cell apoptosis without carrier‐mediated toxicity. Silencing of Cyclin D1 induced apoptosis despite a twofold “compensation” upregulation of Cyclin D2. Upon simultaneous silencing of all three genes, nearly 75% of JeKo‐1 cells were apoptosing 3 days post‐transfection. Furthermore, cells proliferated at only 15% of their pretreatment rate. These data suggest that lipid nanoparticles‐formulated, multiplexed siRNA “cocktails” may serve as a beneficial addition to the treatment regimens for mantle cell lymphoma and other aggressive cancers.

Complex karyotype in patients with mantle cell lymphoma predicts inferior survival and poor response to intensive induction therapy

BACKGROUND

Risk stratification of newly diagnosed patients with mantle cell lymphoma (MCL) primarily is based on the MCL International Prognostic Index (MIPI) and Ki-67 proliferative index. Single-center studies have reported inferior outcomes in patients with a complex karyotype (CK), but this remains an area of controversy.

METHODS

The authors retrospectively reviewed 483 patients from 5 academic centers in the United States and described the effect of a CK on survival outcomes in individuals with MCL.

RESULTS

A CK was found to be associated with inferior overall survival (OS) (4.5 vs 11.6 years; P<.01) and progression-free survival (PFS) (1.9 vs 4.4 years; P<.01). In patients who underwent high-intensity induction followed by autologous stem cell transplantation (ASCT) in first remission, a CK was associated with poor OS (5.1 vs 11.6 years; P = .04) and PFS (3.6 vs 7.8 years; P<.01). Among patients with a CK, high-intensity induction had no effect on OS (4.5 vs 3.8 years; P = .77) nor PFS (2.3 vs 1.5 years; P = .46). Similarly, ASCT in first remission did not improve PFS (3.5 vs 1.2 years; P = .12) nor OS (5.1 vs 4.0 years; P = .27). On multivariable analyses with Ki-67 and MIPI, only CK was found to be predictive of OS (hazard ratio [HR], 1.98; 95% confidence interval [95% CI], 1.12-3.49 [P = .02]), whereas both CK (HR, 1.91; 95% CI, 1.17-3.12 [P = .01]) and Ki-67 >30% (HR, 1.86; 95% CI, 1.06-3.28 [P = .03]) were associated with inferior PFS. Multivariable analysis did not identify any specific cytogenetic abnormalities associated with inferior survival.

CONCLUSIONS

CK appears to be independently associated with inferior outcomes in patients with MCL regardless of the intensity of induction therapy and receipt of ASCT. Cytogenetics should be incorporated into the workup of a new diagnosis of MCL and novel therapeutic approaches should be investigated for patients with CK. Cancer 2018;124:2306-15. © 2018 American Cancer Society.

Gene-modified NK-92MI cells expressing a chimeric CD16-BB-ζ or CD64-BB-ζ receptor exhibit enhanced cancer-killing ability in combination with therapeutic antibody

Natural killer (NK) cells play a pivotal role in monoclonal antibody-mediated immunotherapy through the antibody-dependent cell-mediated cytotoxicity (ADCC) mechanism. NK-92MI is an interleukin-2 (IL-2)-independent cell line, which was derived from NK-92 cells with superior cytotoxicity toward a wide range of tumor cells in vitro and in vivo. Nonetheless, the Fc-receptor (CD16) that usually mediates ADCC is absent in NK-92 and NK-92MI cells. To apply NK-92MI cell-based immunotherapy to cancer treatment, we designed and generated two chimeric receptors in NK-92MI cells that can bind the Fc portion of human immunoglobulins. The construct includes the low-affinity Fc receptor CD16 (158F) or the high-affinity Fc receptor CD64, with the addition of the CD8a extracellular domain, CD28 transmembrane domains, two costimulatory domains (CD28 and 4-1BB), and the signaling domain from CD3ζ. The resulting chimeric receptors, termed CD16-BB-ζ and CD64-BB-ζ, were used to generate modified NK-92MI cells expressing the chimeric receptor, which were named NK-92MI^hCD16 and NK-92MI^hCD64 cells, respectively. We found that NK-92MI^hCD16 and NK-92MI^hCD64 cells significantly improved cytotoxicity against CD20-positive non-Hodgkin's lymphoma cells in the presence of rituximab. These results suggest that the chimeric receptor-expressing NK-92MI cells may enhance the clinical responses to currently available anticancer monoclonal antibodies.

Paclitaxel synergizes with exposure time adjusted CD22-targeting immunotoxins against B-cell malignancies

CD22-targeted recombinant immunotoxins (rIT) are active in hairy cell leukemia or acute lymphoblastic leukemia (ALL), but not in mantle cell lymphoma (MCL) patients. The goal was to enhance rIT efficacy in vivo and to define a strong combination treatment. Activity of Moxetumomab pasudotox (Moxe) and LR combined with paclitaxel was tested against MCL cell lines in vitro and as bolus doses or continuous infusion in xenograft models. In the KOPN-8 ALL xenograft, Moxe or paclitaxel alone was active, but all mice died from leukemia; when combined, 60% of the mice achieved a sustained complete remission. Against MCL cells in vitro, LR was more active than Moxe and the cells had to be exposed to rIT for more than 24 hours for them to die. To maintain high blood levels in vivo, LR was administered continuously by 7-day pumps achieving a well-tolerated steady plasma concentration of 45 ng/ml. In JeKo-1 xenografts, continuously administered LR was 14-fold more active than bolus doses and the combination with paclitaxel additionally improved responses by 135-fold. Maintaining high rIT-plasma levels greatly improves responses in the JeKo-1 model and paclitaxel substantially enhances bolus and continuously infused rIT, supporting a clinical evaluation against B-cell malignancies.

Potential added value of a RT-qPCR method of SOX 11 expression, in the context of a multidisciplinary diagnostic assessment of B cell malignancies

Background

Expression of SRY [sex-determining region Y]-box11 (SOX11) is specific to mantle cell lymphoma (MCL) and contributes, in conjunction with immunoglobulin variable heavy chain gene mutation status, to the identification of two forms of this disease.

Methods

The aim of this report was firstly, to design an easy and suitable RT-qPCR method to quantify SOX11 mRNA expression in mantle cell lymphoma and other B cell malignancies with the proper reference gene; secondly, to define the best threshold of relative quantity of SOX11 mRNA in order to reach the best compromise between sensitivity and specificity.

Results

For best discrimination of MCL and non-MCL groups we determined an area under the curve (AUC) of 0.9750 and a threshold of 1.76 with 100% sensitivity and 88% specificity. AUC and threshold values of respectively 0.91/1.346 [87% sensitivity, 80% specificity] and 0.9525/1.7120 [100% sensitivity, 88% specificity] for GAPDH and RPLP0 respectively denote that the RPLP0 reference gene alone is sufficient for PCR housekeeping gene.

Conclusion

This work describes an RT-qPCR assay for SOX11 expression in order to better characterize MCL at diagnosis. Further studies on larger cohorts are needed to evaluate this molecular tool, especially for the follow-up of minimal residual disease.

Electronic supplementary material

The online version of this article (10.1186/s40164-018-0097-6) contains supplementary material, which is available to authorized users.

A B-cell receptor-related gene signature predicts survival in mantle cell lymphoma: results from the Fondazione Italiana Linfomi MCL-0208 trial

Mantle cell lymphoma patients have variable clinical courses, ranging from indolent cases that do not require immediate treatment to aggressive, rapidly progressing diseases. Thus, diagnostic tools capable of stratifying patients according to their risk of relapse and death are needed. This study included 83 samples from the Fondazione Italiana Linfomi MCL-0208 clinical trial. Through gene expression profiling and quantitative real-time PCR we analyzed 46 peripheral blood and 43 formalin-fixed paraffin-embedded lymph node samples. A prediction model to classify patients was developed. By analyzing the transcriptome of 27 peripheral blood samples, two subgroups characterized by a differential expression of genes from the B-cell receptor pathway (B-cell receptor^low and B-cell receptor^high) were identified. The prediction model based on the quantitative real-time PCR values of six representative genes (AKT3, BCL2, BTK, CD79B, PIK3CD, and SYK), was used to classify the 83 cases (43 B-cell receptor^low and 40 B-cell receptor^high). The B-cell receptor^high signature associated with shorter progression-free survival (P=0.0074), selected the mantle cell lymphoma subgroup with the shortest progression-free survival and overall survival (P=0.0014 and P=0.029, respectively) in combination with high (>30%) Ki-67 staining, and was an independent predictor of short progression- free survival along with the Mantle Cell Lymphoma International Prognostic Index-combined score. Moreover, the clinical impact of the 6- gene signature related to the B-cell receptor pathway identified a mantle cell lymphoma subset with shorter progression-free survival intervals also in an external independent mantle cell lymphoma cohort homogenously treated with different schedules. In conclusion, this 6-gene signature associates with a poor clinical response in the context of the MCL- 0208 clinical trial. (clinicaltrials.gov identifier: 02354313).

Gene mutations and actionable genetic lesions in mantle cell lymphoma

Mutations and epigenetic alterations are key events in transforming normal cells to cancer cells. Mantle cell lymphoma (MCL), a non-Hodgkin's lymphoma of the B-cell, is an aggressive malignancy with poor prognosis especially for those patients who are resistant to the frontline drugs. There is a great need to describe the molecular basis and mechanism of drug resistance in MCL to develop new strategies for treatment. We reviewed frequent somatic mutations and mutations involving the B-cell pathways in MCL and discussed clinical trials that attempted to disrupt these gene pathways and/or epigenetic events. Recurrent gene mutations were discussed in the light of prognostic and therapeutic opportunity and also the challenges of targeting these lesions. Mutations in the ATM, CCND1, TP53, MLL2, TRAF2 and NOTCH1 were most frequently encountered in mantle cell lymphoma. Translational models should be built that would assess mutations longitudinally to identify important compensatory, pro-survival and anti-apoptic pathways and actionable genetic targets.

Role of Bruton's tyrosine kinase in B cells and malignancies

Bruton’s tyrosine kinase (BTK) is a non-receptor kinase that plays a crucial role in oncogenic signaling that is critical for proliferation and survival of leukemic cells in many B cell malignancies. BTK was initially shown to be defective in the primary immunodeficiency X-linked agammaglobulinemia (XLA) and is essential both for B cell development and function of mature B cells. Shortly after its discovery, BTK was placed in the signal transduction pathway downstream of the B cell antigen receptor (BCR). More recently, small-molecule inhibitors of this kinase have shown excellent anti-tumor activity, first in animal models and subsequently in clinical studies. In particular, the orally administered irreversible BTK inhibitor ibrutinib is associated with high response rates in patients with relapsed/refractory chronic lymphocytic leukemia (CLL) and mantle-cell lymphoma (MCL), including patients with high-risk genetic lesions. Because ibrutinib is generally well tolerated and shows durable single-agent efficacy, it was rapidly approved for first-line treatment of patients with CLL in 2016. To date, evidence is accumulating for efficacy of ibrutinib in various other B cell malignancies. BTK inhibition has molecular effects beyond its classic role in BCR signaling. These involve B cell-intrinsic signaling pathways central to cellular survival, proliferation or retention in supportive lymphoid niches. Moreover, BTK functions in several myeloid cell populations representing important components of the tumor microenvironment. As a result, there is currently a considerable interest in BTK inhibition as an anti-cancer therapy, not only in B cell malignancies but also in solid tumors. Efficacy of BTK inhibition as a single agent therapy is strong, but resistance may develop, fueling the development of combination therapies that improve clinical responses. In this review, we discuss the role of BTK in B cell differentiation and B cell malignancies and highlight the importance of BTK inhibition in cancer therapy.

Acalabrutinib in relapsed or refractory mantle cell lymphoma (ACE-LY-004): a single-arm, multicentre, phase 2 trial

BACKGROUND

Bruton tyrosine kinase is a clinically validated target in mantle cell lymphoma. Acalabrutinib (ACP-196) is a highly selective, potent Bruton tyrosine kinase inhibitor developed to minimise off-target activity.

METHODS

In this open-label, phase 2 study, oral acalabrutinib (100 mg twice per day) was given to patients with relapsed or refractory mantle cell lymphoma, until disease progression or unacceptable toxicity. The primary endpoint was overall response assessed according to the Lugano classification, and safety analyses were done in all participants. This trial is registered with ClinicalTrials.gov, number NCT02213926.

FINDINGS

From March 12, 2015, to Jan 5, 2016, 124 patients with relapsed or refractory mantle cell lymphoma were enrolled and all patients received treatment; median age 68 years. Patients received a median of two (IQR 1-2) previous therapies. At a median follow-up of 15·2 months, 100 (81%) patients achieved an overall response and 49 (40%) patients achieved a complete response. The Kaplan-Meier estimated medians for duration of response, progression-free survival, and overall survival were not reached; the 12-month rates were 72% (95% CI 62-80), 67% (58-75), and 87% (79-92%), respectively. The most common adverse events were primarily grade 1 or 2 and were headache (47 [38%]), diarrhoea (38 [31%]), fatigue (34 [27%]), and myalgia (26 [21%]). The most common grade 3 or worse adverse events were neutropenia (13 [10%]), anaemia (11 [9%]), and pneumonia (six [5%]). There were no cases of atrial fibrillation and one case of grade 3 or worse haemorrhage. The median duration of treatment was 13·8 months. Treatment was discontinued in 54 (44%) patients, primarily due to progressive disease (39 [31%]) and adverse events (seven [6%]).

INTERPRETATION

Acalabrutinib treatment provided a high rate of durable responses and a favourable safety profile in patients with relapsed or refractory mantle cell lymphoma. These findings suggest an important role for acalabrutinib in the treatment of this disease population.

FUNDING

Acerta Pharma, a member of the AstraZeneca Group.

The pathophysiological significance of PPM1D and therapeutic targeting of PPM1D-mediated signaling by GSK2830371 in mantle cell lymphoma

PPM1D is a serine/threonine phosphatase that negatively regulates key DNA damage response proteins, such as p53, p38 MAPK, histone H2A.X, and ATM. We investigated the pathophysiological significance of PPM1D and its therapeutic targeting by the novel PPM1D inhibitor GSK2830371 in mantle cell lymphoma (MCL). Oncomine-based analyses indicated increased PPM1D mRNA levels in MCL cells compared with their normal counterpart cells. Higher PPM1D expression was associated with higher expression of the proliferation gene signature and poorer prognosis in patients. Eight MCL (three p53 wild-type and five mutant) cell lines were exposed to GSK2830371. GSK2830371 inhibited the cell growth, being prominent in p53 wild-type cells. GSK2830371 induced apoptosis in sensitive cells, as evidenced by induction of phosphatidylserine externalization and loss of mitochondrial membrane potential. p53 knockdown de-sensitized cell sensitivity. GSK2830371 increased the levels of total and Ser15-phosphorylated p53, and p53 targets p21 and PUMA. GSK2830371 and the MDM2 inhibitor Nutlin-3a acted synergistically in p53 wild-type cells. Interestingly, GSK2830371 sensitized MCL cells to bortezomib and doxorubicin in p53 wild-type and mutant cells; p38 signaling appeared to be involved in the GSK2830371/bortezomib lethality. PPM1D inhibition may represent a novel therapeutic strategy for MCL, which can be exploited in combination therapeutic strategies for MCL.

Current trials for frontline therapy of mantle cell lymphoma

Mantle cell lymphoma (MCL) is a rare and incurable subtype of non-Hodgkin's lymphoma that generally affects older individuals. However, the use of high-dose therapy and autologous stem cell transplant has improved significantly the prognosis of this hematological malignancy, but at the cost of increased toxicities, such as acute toxic death and secondary malignancies. But thanks to a rising understanding of the biology of MCL, the explosion of specifically targeted new efficacious agents, immunotherapy agents, and cellular therapies in the frontline setting, the prognosis of MCL is expected to improve dramatically.The initial treatment of MCL is currently not standardized and the therapeutic landscape of MCL is rapidly evolving. This review provides an extensive overview of the current frontline therapy trials for MCL and presents the results of innovative regimen, including some integrating novel agents and desintensified chemotherapy.

Platelet Count before Peripheral Blood Stem Cell Mobilization Is Associated with the Need for Plerixafor But Not with the Collection Result

BACKGROUND

A low platelet count before mobilization has recurrently been identified as risk factor for poor mobilization.

METHODS

To determine the relevance of this finding for peripheral blood stem cell (PBSC) mobilization, including pre-emptive or rescue plerixafor in the case of poor mobilization, we retrospectively analyzed all patients undergoing PBSC collection at our institution between January 2014 and December 2015 (n = 380).

RESULTS

In total, 99% of the patients (377/380) successfully collected a minimum of 2 × 106 CD34+ cells/kg body weight sufficient for a single transplant. Rescue or pre-emptive plerixafor was administered to 11% of the patients (42/380). No correlations between the platelet count before mobilization and the number of peripheral blood CD34+ cells or the CD34+ cell collection result were detected in the entire population or the subgroups according to diagnosis (newly diagnosed multiple myeloma, relapsed multiple myeloma, lymphoma, amyloid light-chain amyloidosis, sarcoma, or germ cell tumor). However, patients requiring pre-emptive or rescue plerixafor had a significantly lower platelet count before mobilization (217/nl vs. 245/nl; p = 0.004).

CONCLUSION

With the current state of the art PBSC mobilization strategies, the platelet count before mobilization was not associated with the CD34+ cell collection result but was associated with the need for pre-emptive or rescue application of plerixafor.

Smoldering mantle cell lymphoma

Background

Mantle cell lymphoma (MCL) is an aggressive disease, with poor prognosis and a limited survival. However, some patients with indolent MCL can survive beyond 7~10 years. These patients remain largely asymptomatic and can be in observation for a long time without any treatment. The process of “wait and watch” leaves these patients with the potential risk of evolution to classic, aggressive MCL. On the other hand, early treatment for these patients may not impact overall survival but rather affects the quality of life. Therefore, it is essential to clearly identify this type of indolent MCL at the time of diagnosis.

Results

Reported findings of indolent presentation of MCL include: lack of B symptoms, normal serum lactic dehydrogenase (LDH) and β2-microglobulin levels (β2M), low MCL-International Prognostic Index (MIPI) score, maximum tumor diameter less than 3 cm, spleen size < 20 cm, positron emission tomography/computerized tomography with the Standard Uptake Value max <6, Ki-67 less than 30%, with some particular immunophenotype, such as CD5 and CD38 negative, markedly increased CD23 positive lymphocytes proportions, high expression of CD200, kappa light chain restriction, without C-myc, TP53 and NOTCH1/2 mutations, non-blastoid/pleomorphic histology, and no tumor growth on reevaluation every 2~3 months (followed for at least 6 months). Imaging evaluation may only be performed in the presence of disease-related symptoms or organ involvement. Meanwhile, if novel nodal or extranodal lesion is found, biopsy is mandatory to exclude lymphoma.

Common clinopathological forms of indolent presentations include monoclonal B lymphocytosis with t (11; 14); “indolent leukemic” presentation of MCL with involvement of peripheral blood, bone marrow involvement, splenomegaly, and minimal lymphadenopathies and in situ lymphoma (often found in lymph nodes removed for other reasons, and in gastrointestinal biopsies).

Conclusions

Considering these distinct indolent clinical presentations with particular features in cytology and gene mutational status, we propose to include these MCL clinical presentations under the umbrella of “Smoldering Mantle Cell Lymphoma”.

miR-223 is repressed and correlates with inferior clinical features in mantle cell lymphoma through targeting SOX11

Mantle cell lymphoma (MCL) is an aggressive lymphoid malignancy characterized by cytogenetic aberration of t(11;14), although it is not the prerequisite. Until now, the pathogenesis of MCL has not been fully interpreted. Our current study showed that microRNA (miR)-223 was downregulated in purified CD19⁺ lymphocytes from MCL patients (n = 21) compared with that of healthy donors (n = 20). In addition, patients with a high-risk Mantle Cell Lymphoma International Prognostic Index (MIPI) score, elevated lactate dehydrogenase, and Eastern Cooperative Oncology Group performance status >2 were more likely to have much lower miR-223 expression. Furthermore, low miR-223 expression predicted inferior overall survival regardless of treatment in our cohort of 21. To explore the role of miR-223 in MCL, we constructed an ectopic miR-223 MCL cell line and revealed that miR-223 inhibited cell proliferation and promoted G₀/G₁ accumulation and cell apoptosis. A database search showed that SOX11, a crucial transcription factor in MCL, is the putative target of miR-223. In support of this, we observed a much lower level of SOX11 protein in miR-223-overexpressing cells than in parental cells. Further, the luciferase reporter assay confirmed that miR-223 at the posttranscriptional level suppressed the wild-type 3'-untranslated region of SOX11 but not the mutated one. Finally, miR-223 was found to be negatively correlated with the mRNA level of SOX11 in clinical samples. Our work demonstrates for the first time that miR-223 is repressed and correlated with high-risk clinical features in MCL, which provides a potential molecule to target to optimize MCL management.

Trends and variations in mantle cell lymphoma incidence from 1995 to 2013: A comparative study between Texas and National SEER areas

Background

Few studies have assessed mantle cell lymphoma (MCL) incidence trends in the U.S. National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) areas. Previous studies were 5 to 9 years old and MCL incidence in Texas remains unknown. This study updated the temporal trends and variations of MCL incidence in the SEER areas and compared them with counterpart data in Texas.

Results

From 1995 to 2013, there were 2, 435 and 5, 193 newly diagnosed MCL patients in Texas and SEER areas. Age-adjusted MCL incidence was 0.91 per 100,000 persons per year in Texas and 1.01 in SEER areas. MCL incidence increased steadily with an annual percent change (APC) of 2.56% in SEER areas and an APC of 2.16% in Texas. In SEER areas, APCs for MCL incidence were significantly different from zero in patients with advanced stage tumor (3.33%), male (2.71%), elderly patients ≥ 80 years old (4.21%) and non-Hispanic white patients (2.83%) (all P < 0.05). Similar patterns were found in Texas for both incidence rates and APCs.

Materials and methods

We identified all adult patients with newly diagnosed MCL in Texas Cancer Registry and SEER databases from 1995 to 2013. Age-adjusted incidence rates were calculated and negative binomial regression model was used to assess the factors associated with MCL incidence.

Conclusions

MCL incidence rates increased over time in both Texas and SEER areas, with increases being greater in male, non-Hispanic white, and elderly patient ≥70 years with advanced stage tumors. Texas has similar MCL incidence trends and disparities as the national SEER areas.

Observational study of lenalidomide in patients with mantle cell lymphoma who relapsed/progressed after or were refractory/intolerant to ibrutinib (MCL-004)

BACKGROUND

The observational MCL-004 study evaluated outcomes in patients with relapsed/refractory mantle cell lymphoma who received lenalidomide-based therapy after ibrutinib failure or intolerance.

METHODS

The primary endpoint was investigator-assessed overall response rate based on the 2007 International Working Group criteria.

RESULTS

Of 58 enrolled patients (median age, 71 years; range, 50-89), 13 received lenalidomide monotherapy, 11 lenalidomide plus rituximab, and 34 lenalidomide plus other treatment. Most patients (88%) had received ≥ 3 prior therapies (median 4; range, 1-13). Median time from last dose of ibrutinib to the start of lenalidomide was 1.3 weeks (range, 0.1-21.7); 45% of patients had partial responses or better to prior ibrutinib. Primary reasons for ibrutinib discontinuation were lack of efficacy (88%) and ibrutinib toxicity (9%). After a median of two cycles (range, 0-11) of lenalidomide-based treatment, 17 patients responded (8 complete responses, 9 partial responses), for a 29% overall response rate (95% confidence interval, 18-43%) and a median duration of response of 20 weeks (95% confidence interval, 2.9 to not available). Overall response rate to lenalidomide-based therapy was similar for patients with relapsed/progressive disease after previous response to ibrutinib (i.e., ≥PR) versus ibrutinib-refractory (i.e., ≤SD) patients (30 versus 32%, respectively). The most common all-grade treatment-emergent adverse events after lenalidomide-containing therapy (n = 58) were fatigue (38%) and cough, dizziness, dyspnea, nausea, and peripheral edema (19% each). At data cutoff, 28 patients have died, primarily due to mantle cell lymphoma.

CONCLUSION

Lenalidomide-based treatment showed clinical activity, with no unexpected toxicities, in patients with relapsed/refractory mantle cell lymphoma who previously failed ibrutinib therapy.

TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT02341781 . Date of registration: January 14, 2015.

Randomized phase II study of a bendamustine monotherapy schedule for relapsed or refractory low-grade B-cell non-Hodgkin lymphoma or mantle cell lymphoma (RABBIT-14)

The aim of this randomized phase II study was to improve the treatment delays and discontinuations associated with bendamustine use by comparing the effect of Benda-14 (intravenous bendamustine, 120 mg/m² on days 1 and 15, repeated every 4 weeks for a total of 6 cycles) with those of the standard treatment in relapsed indolent lymphoma and/or mantle cell lymphoma. Forty-six patients were randomly assigned to the treatments from September 2012 to February 2016. Treatment accomplishment rate and median relative dose intensity were similar in both arms: 38 and 63.4% in the Benda-14 arm and 41 and 66.3% in the standard treatment arm, respectively. The overall response rate and median progression-free survival, respectively, were 83% and 21.0 months for Benda-14, and 77% and 15.5 months for the standard treatment. Benda-14 induced favorable responses with less frequent hematological toxicities.

Survival benefit of mantle cell lymphoma patients enrolled in clinical trials; a joint study from the LYSA group and French cancer registries

PURPOSE

Mantle cell lymphoma (MCL) is a rare non-Hodgkin's lymphoma entity with a poor prognosis. Therapeutic advances have improved the survival of patients enrolled in clinical trials; however, their impact on patients outside clinical trials remains unclear. In this work, we compared patient outcome inside and outside clinical trials.

METHODS

We identified MCL patients recorded in six French population-based registries between 2008 and 2012 to perform a comparison with patients enrolled in two prospective multicenter MCL clinical trials conducted by the LYSA group during the same period. Variables associated with inclusion in a clinical trial were identified using a logistic regression. Pohar-Perme estimator and Nelson et al. flexible parametric model was used to estimate net survival probabilities and prognosis factors on excess mortality.

RESULTS

A total of 312 registry patients were compared to the 372 patients enrolled in LYSA clinical trials. Patients included in clinical trials were younger (median age 60 vs 74, p < 0.001). Age and Ann Arbor stage IV were independently associated with enrollment [OR = 0.09 (0.06-0.12) and OR = 1.61 (1.11-2.34), respectively]. The 4 year net survival was better in clinical trials [79.9% (75.9-84.7) vs 60.3% (53.6-67.0)]. This result was confirmed in multivariate analysis in patients older than 65 years with a lower excess mortality rate [0.33 (0.17-0.66)].

CONCLUSIONS

MCL included in trials are highly selected patients who are not representative of MCL patients who are encountered in everyday practice. With widened inclusion criteria, clinical trial patients could be more representative of the general population.

Rituximab after Autologous Stem-Cell Transplantation in Mantle-Cell Lymphoma

BACKGROUND

Mantle-cell lymphoma is generally incurable. Despite high rates of complete response after initial immunochemotherapy followed by autologous stem-cell transplantation, patients have relapses. We investigated whether rituximab maintenance therapy at a dose of 375 mg per square meter of body-surface area administered every 2 months for 3 years after transplantation would prolong the duration of response.

METHODS

In a phase 3 trial involving 299 patients who were younger than 66 years of age at diagnosis, we randomly assigned 240 patients to receive rituximab maintenance therapy or to undergo observation after autologous stem-cell transplantation (120 patients per group); 59 patients did not undergo randomization. The primary end point was event-free survival (with an event defined as disease progression, relapse, death, allergy to rituximab, or severe infection) after transplantation among patients who underwent randomization.

RESULTS

After four courses of immunochemotherapy induction (rituximab, dexamethasone, cytarabine, and a platinum derivative [R-DHAP]), the overall response rate was 89%, and the complete response rate 77%. Transplantation was performed in 257 patients. The median follow-up from randomization after transplantation was 50.2 months (range, 46.4 to 54.2). Starting from randomization, the rate of event-free survival at 4 years was 79% (95% confidence interval [CI], 70 to 86) in the rituximab group versus 61% (95% CI, 51 to 70) in the observation group (P=0.001). The rate of progression-free survival at 4 years was 83% (95% CI, 73 to 88) in the rituximab group versus 64% (95% CI, 55 to 73) in the observation group (P<0.001). The rate of overall survival was 89% (95% CI, 81 to 94) in the rituximab group versus 80% (95% CI, 72 to 88) in the observation group (P=0.04). According to a Cox regression unadjusted analysis, the rate of overall survival at 4 years was higher in the rituximab group than in the observation group (hazard ratio for death, 0.50; 95% CI, 0.26 to 0.99; P=0.04).

CONCLUSIONS

Rituximab maintenance therapy after transplantation prolonged event-free survival, progression-free survival, and overall survival among patients with mantle-cell lymphoma who were younger than 66 years of age at diagnosis. (Funded by Roche and Amgen; LyMa ClinicalTrials.gov number, NCT00921414 .).

Surveillance imaging in mantle cell lymphoma in first remission lacks clinical utility

Mantle cell lymphoma (MCL) is a heterogeneous disease with high relapse rates. Limited data guide the use of surveillance imaging following treatment. We constructed a retrospective cohort from two academic institutions of patients with MCL who completed first-line therapy and underwent follow-up for relapse, analyzing the effect of surveillance imaging on survival. Of 217 patients, 102 had documented relapse, with 38 (37%) diagnosed by surveillance imaging and 64 (63%) by other methods. Relapse diagnosis by surveillance imaging had no significant advantage in overall survival from diagnosis date (hazard ratio [HR] = 0.80, p = .39) or relapse date (HR = 0.72, p = .22). Of 801 surveillance images, PET/CT had a positive predictive value (PPV) of 24% and number needed-to-scan/treat (NNT) of 51 to detect one relapse, and CT had a PPV of 49% and NNT of 24. For MCL after first-line therapy, relapse detection by surveillance imaging was not associated with improved survival and lacks clinical benefit.

Aberrant expression of CD10 and BCL6 in mantle cell lymphoma

AIMS

Mantle cell lymphoma (MCL) is characterized by distinctive histological and molecular features. Aberrant expression of BCL6 and CD10 has been reported occasionally, but the biological features of such cases are largely unknown. This study aimed to define the epidemiological, histological and cytogenetic characteristics of BCL6 and CD10-positive MCLs, also investigating possible biological features.

METHODS AND RESULTS

A total of 165 cases of cyclin D1 and t(11;14)(q13;q34)-positive MCLs were studied for CD10 and BCL6 immunohistochemical expression, which was documented in 26 of 165 (15.8%) cases (BCL6 17 of 165; CD10 11 of 165; BCL6 and CD10 co-expression two of 165). CD10-positivity was significantly more frequent in females (63.3%; P < 0.01). Either expression correlated significantly with higher mean proliferation index and higher prevalence of MUM1 positivity (P < 0.05). Fluorescence in-situ hybridization (FISH) for BCL6 (3q27) gene derangements was performed on the BCL6- and CD10-positive cases and 98 matched controls: amplifications were documented more frequently in BCL6-positive than -negative cases (50.0% versus 19.4% of cases) (P < 0.05). The mutational status of the variable immunoglobulin heavy chain genes (IGVH) was investigated by Sanger sequencing: five of the six successfully tested cases (83.3%) showed no somatic hypermutations.

CONCLUSIONS

Aberrant CD10 and BCL6 expression defines a subset of MCLs with higher mean Ki-67 index and higher prevalence of MUM1 expression. BCL6 protein positivity correlates with cytogenetic aberrations involving the BCL6 gene. Although examined successfully in few cases, the high prevalence of unmutated IGVH genes also points at a pregerminal cell origin for these phenotypically aberrant cases.

A Phase 1 Study to Assess the Relative Bioavailability of Two Capsule Formulations of Ixazomib, an Oral Proteasome Inhibitor, in Patients With Advanced Solid Tumors or Lymphoma

The oral proteasome inhibitor ixazomib is approved in multiple countries in combination with lenalidomide and dexamethasone for the treatment of patients with multiple myeloma who have received at least 1 prior therapy. Two oral capsule formulations of ixazomib have been used during clinical development. This randomized, 2-period, 2-sequence crossover study (Clinicaltrials.gov identifier NCT01454076) assessed the relative bioavailability of capsule B in reference to capsule A in adult patients with advanced solid tumors or lymphoma. The study was conducted in 2 parts. In cycle 1 (pharmacokinetic cycle), patients received a 4-mg dose of ixazomib as capsule A or capsule B on day 1, followed by a 4-mg dose of the alternate capsule formulation on day 15. Pharmacokinetic samples were collected over 216 hours postdose. After the pharmacokinetic cycle, patients could continue in the study and receive ixazomib (capsule B only) on days 1, 8, and 15 of each 28-day cycle. Twenty patients were enrolled; of these, 14 were included in the pharmacokinetic-evaluable population. Systemic exposures of ixazomib were similar after administration of capsule A or capsule B. The geometric least-squares mean ratios (capsule B versus capsule A) were 1.16 for C_max (90% confidence interval [CI], 0.84-1.61) and 1.04 for AUC_0-216 (90%CI, 0.91-1.18). The most frequently reported grade 3 drug-related adverse events were fatigue (15%) and nausea (10%); there were no grade 4 drug-related adverse events. These results support the combined analysis of data from studies that used either formulation of ixazomib during development.

Structural optimization elaborates novel potent Akt inhibitors with promising anticancer activity

Targeting of Akt has been validated as a well rationalized approach to cancer treatment, and represents a promising therapeutic strategy for aggressive hematologic malignancies. We describe herein an exploration of novel Akt inhibitors for cancer therapy through structural optimization of previously described 4-(piperazin-1-yl)-7H-pyrrolo[2,3-d]pyrimidine derivatives. Our studies yielded a novel series of pyrrolopyrimidine based phenylpiperidine carboxamides capable of potent inhibition of Akt1. Notably, 10h exhibited robust antiproliferative effects in both mantle cell lymphoma cell lines and primary patient tumor cells. Low micromolar doses of 10h induced cell apoptosis and cell cycle arrest in G₂/M phase, and significantly downregulated the phosphorylation of Akt downstream effectors GSK3β and S6 in Jeko-1 cells.

Cytoplasmic expression of C-MYC protein is associated with risk stratification of mantle cell lymphoma

Aim

To investigate the association of C-MYC protein expression and risk stratification in mantle cell lymphoma (MCL), and to evaluate the utility of C-MYC protein as a prognostic biomarker in clinical practice.

Methods

We conducted immunohistochemical staining of C-MYC, Programmed cell death ligand 1 (PD-L1), CD8, Ki-67, p53 and SRY (sex determining region Y) -11 (SOX11) to investigate their expression in 64 patients with MCL. The staining results and other clinical data were evaluated for their roles in risk stratification of MCL cases using ANOVA, Chi-square, and Spearman’s Rank correlation coefficient analysis.

Results

Immunohistochemical staining in our study indicated that SOX11, Ki-67 and p53 presented nuclear positivity of tumor cells, CD8 showed membrane positivity in infiltrating T lymphocytes while PD-L1 showed membrane and cytoplasmic positivity mainly in macrophage cells and little in tumor cells. We observed positive staining of C-MYC either in the nucleus or cytoplasm or in both subcellular locations. There were significant differences in cytoplasmic C-MYC expression, Ki-67 proliferative index of tumor cells, and CD8 positive tumor infiltrating lymphocytes (CD8+TIL) among three risk groups (P = 0.000, P = 0.037 and P=0.020, respectively). However, no significant differences existed in the expression of nuclear C-MYC, SOX11, p53, and PD-L1 in MCL patients with low-, intermediate-, and high risks. In addition, patient age and serum LDH level were also significantly different among 3 groups of patients (P = 0.006 and P = 0.000, respectively). Spearman’s rank correlation coefficient analysis indicated that cytoplasmic C-MYC expression, Ki-67 index, age, WBC, as well as LDH level had significantly positive correlations with risk stratification (P = 0.000, 0.015, 0.000, 0.029 and 0.000, respectively), while CD8+TIL in tumor microenvironment negatively correlated with risk stratification of patients (P = 0.006). Patients with increased positive cytoplasmic expression of C-MYC protein and decreased CD8+TIL appeared to be associated with a poor response to chemotherapy, but the correlation was not statistically significant.

Conclusion

Our study suggested that assessment of cytoplasmic C-MYC overexpression and cytotoxic T lymphocytes (CTLs) by immunohistochemical staining might be helpful for MCL risk stratification and outcome prediction. However, large cohort studies of MCL patients with complete follow up are needed to validate our speculation.

Results from the Belgian mantle cell lymphoma registry

INTRODUCTION

Mantle cell lymphoma is a B-cell non-Hodgkin's lymphoma characterized by a t(11;14), resulting in overexpression of cyclin D1. Conventional chemotherapy obtains frequent (but short) remissions, leading to a poor median overall survival (OS) of 3-5 years. To obtain more information about the prevalence and current treatment of Mantle cell lymphoma (MCL) in Belgium, we collected data in a Belgian registry of MCL.

MATERIALS AND METHODS

All Belgian MCL patients, t(11;14) and/or cyclin D1 positive, seen in hematology departments over a one-year period (April 2013-March 2014) were included. Data about patient characteristics, histology, treatment lines, and response were compiled and retrospectively analyzed.

RESULTS

Four hundred and four patients were included with a median age at diagnosis of 64 years (range 23-96 years) and a male predominance (72%). For 2013, we calculated a prevalence of at least 36.2 per million and an incidence of at least 7.0 per million in the Belgian population. Characteristics at diagnosis involved lymphadenopathy (82%), splenomegaly (44%), B-symptoms (39%), and hepatomegaly (10%). Bone marrow invasion was present at diagnosis in 77%. Stage at diagnosis was advanced in the majority of cases. The median number of treatment lines was 1. Type of first line treatment included a combination of anthracyclin and cytarabine-based regimen (34%), anthracyclin (39%), and other. Rituximab was used in 88% of first line treatments. In 44% first line treatment was followed by autologous stem cell transplantation.

CONCLUSION

The analysis of this Belgian MCL registry provides insight in the epidemiology, demographics, and current treatment of our Belgian MCL population.

New Molecular Assay for the Proliferation Signature in Mantle Cell Lymphoma Applicable to Formalin-Fixed Paraffin-Embedded Biopsies

Purpose Mantle cell lymphoma is an aggressive B-cell neoplasm that displays heterogeneous outcomes after treatment. In 2003, the Lymphoma/Leukemia Molecular Profiling Project described a powerful biomarker-the proliferation signature-using gene expression in fresh frozen material. Herein, we describe the training and validation of a new assay that measures the proliferation signature in RNA derived from routinely available formalin-fixed paraffin-embedded (FFPE) biopsies. Methods Forty-seven FFPE biopsies were used to train an assay on the NanoString platform, using microarray gene expression data of matched fresh frozen biopsies as a gold standard. The locked assay was applied to pretreatment FFPE lymph node biopsies from an independent cohort of 110 patients uniformly treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone. Seventeen biopsies were tested across three laboratories to assess assay reproducibility. Results The MCL35 assay, which contained a 17-gene proliferation signature, yielded gene expression of sufficient quality to assign an assay score and risk group in 108 (98%) of 110 archival FFPE biopsies. The MCL35 assay assigned patients to high-risk (26%), standard-risk (29%), and low-risk (45%) groups, with different lengths of overall survival (OS): a median of 1.1, 2.6, and 8.6 years, respectively (log-rank for trend, P < .001). In multivariable analysis, these risk groups and the Mantle Cell Lymphoma International Prognostic Index were independently associated with OS ( P < .001 for both variables). Concordance of risk assignment across the three independent laboratories was 100%. Conclusion The newly developed and validated MCL35 assay for FFPE biopsies uses the proliferation signature to define groups of patients with significantly different OS independent of the Mantle Cell Lymphoma International Prognostic Index. Importantly, the analytic and clinical validity of this assay defines it as a reliable biomarker to support risk-adapted clinical trials.

Krüppel-like factor 4 contributes to the pathogenesis of mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive subtype of B-cell non-Hodgkin lymphoma (NHL) with poor prognosis. Krüppel-like factor 4 (KLF4) has been reported as a bi-regulator in malignancies, but little is known about its role in MCL. Here, we showed that KLF4 was downregulated in three MCL cell lines and lymph nodes from MCL patients, which resulted in a negative prognosis. We also found that the regulation of KLF4 could inhibit the proliferation and induce apoptosis of Jeko-1 cells. The lentivirally over-expressed KLF4 protein was found bind to β-catenin and could inhibit downstream molecules such as cyclinD1 and c-Myc. Furthermore, 5-azacytidine could decrease the expression of methyltransferase-1 (DNMT-1) and restore the KLF4 expression in MCL cell lines, indicating that methylation might play an important role in the downregulation of KLF4. KLF4 may be a potential therapeutic target as a tumor suppressor in MCL.

Targeted Drugs as Maintenance Therapy after Autologous Stem Cell Transplantation in Patients with Mantle Cell Lymphoma

The treatment landscape for mantle cell lymphoma (MCL) is rapidly evolving toward the incorporation of novel and biologically targeted pharmaceuticals with improved disease activity and gentler toxicity profiles compared with conventional chemotherapeutics. Upfront intensive treatment of MCL includes autologous stem cell transplantation (SCT) consolidation aimed at deepening and lengthening disease remission, but subsequent relapse occurs. Maintenance therapy after autologous SCT in patients with MCL in remission features lower-intensity treatments given over extended periods to improve disease outcomes. Targeted drugs are a natural fit for this space, and are the focus of considerable clinical investigation. This review summarizes recent advances in the field and their potential impact on treatment practices for MCL.

Gastrointestinal involvement by mantle cell lymphoma observed by endoscopy: A case report

INTRODUCTION

Mantle cell lymphoma (MCL) is a subtype of non-Hodgkin B-cell lymphoma, accounting for 6% of all non-Hodgkin lymphoma. The typical appearance of intestinal MCL is multiple lymphomatous polyposis, whereas presentation as protruding lesions is uncommon. We herein report the case of a 64-year-old male patient who was admitted to our hospital with epigastric pains. On endoscopy, submucosal neoplasma were identified in the gastric antrum, the duodenal bulb, and the rectum. On endoscopic ultrasonography (EUS) (OLYMPUS EUS EU-ME2, Miniprobe sonography), the lesions were homogeneously hypoechoic and originated from the submucous layer or muscularis mucosa. Pathological examination of biopsied specimens from the lesions of the rectum revealed diffuse lymphomatous proliferation and dense infiltration by monomorphic and small cleaved cells with irregularly shaped nuclei. On immunohistochemistry, the cells were positive for cyclin D1, CD20, CD21, SOX-11, and Bcl-2, but negative for CD3 and CD10; these findings were compatible with a diagnosis of MCL.

CONCLUSION

The EUS characteristics initially led to the suspicion of digestive neuroendocrine tumors, since MCL presenting as submucosal tumors on EUS is rarely reported. We herein present this case to suggest clinician to include MCL in the differential diagnosis of submucosal intestinal lesions, as early diagnosis and timely treatment may improve patient prognosis.

Long-Term Response and Possible Cure of Patients With B-Cell Malignancies With Dose-Escalated Rituximab

Rituximab (R), a chimeric monoclonal antibody targeting CD20 antigen on B-cells, has become a standard of care in the treatment of B-cell malignancies, most often in conjunction with cytotoxic chemotherapy. Activity has been demonstrated in many subtypes of B-cell lymphoma, including diffuse large cell lymphoma, follicular lymphoma (FL), mantle cell lymphoma (MCL), chronic lymphocytic leukemia (CLL), lymphocyte-predominant Hodgkin lymphoma, and Waldenström macroglobulinemia (WM). Additionally, dose escalation of R as a single agent has demonstrated improved activity in previously treated/poor prognosis CLL. We present 4 cases of B-cell malignancy (2 CLL variants/MCL, 1 FL, 1 WM) who received dose-escalated R as a single agent and achieved complete response (3 patients) and stable disease/partial response (1 patient) of 6.5+ to 15+ years duration. They have been off treatment for 6.5+ to 15+ years. Toxicity was minimal, with initial infusion reactions similar to those observed with standard dose infusions. There were no serious treatment-related adverse events or infections. Dose escalated R as a single agent may possibly be curative for some patients with B-cell malignancies, unlike the standard empiric dose of 375 mg/m², and deserves further study.

Acidosis Activates Endoplasmic Reticulum Stress Pathways through GPR4 in Human Vascular Endothelial Cells

Acidosis commonly exists in the tissue microenvironment of various pathophysiological conditions such as tumors, inflammation, ischemia, metabolic disease, and respiratory disease. For instance, the tumor microenvironment is characterized by acidosis and hypoxia due to tumor heterogeneity, aerobic glycolysis (the "Warburg effect"), and the defective vasculature that cannot efficiently deliver oxygen and nutrients or remove metabolic acid byproduct. How the acidic microenvironment affects the function of blood vessels, however, is not well defined. GPR4 (G protein-coupled receptor 4) is a member of the proton-sensing G protein-coupled receptors and it has high expression in endothelial cells (ECs). We have previously reported that acidosis induces a broad inflammatory response in ECs. Acidosis also increases the expression of several endoplasmic reticulum (ER) stress response genes such as CHOP (C/EBP homologous protein) and ATF3 (activating transcription factor 3). In the current study, we have examined acidosis/GPR4- induced ER stress pathways in human umbilical vein endothelial cells (HUVEC) and other types of ECs. All three arms of the ER stress/unfolded protein response (UPR) pathways were activated by acidosis in ECs as an increased expression of phosphorylated eIF2α (eukaryotic initiation factor 2α), phosphorylated IRE1α (inositol-requiring enzyme 1α), and cleaved ATF6 upon acidic pH treatment was observed. The expression of other downstream mediators of the UPR, such as ATF4, ATF3, and spliced XBP-1 (X box-binding protein 1), was also induced by acidosis. Through genetic and pharmacological approaches to modulate the expression level or activity of GPR4 in HUVEC, we found that GPR4 plays an important role in mediating the ER stress response induced by acidosis. As ER stress/UPR can cause inflammation and cell apoptosis, acidosis/GPR4-induced ER stress pathways in ECs may regulate vascular growth and inflammatory response in the acidic microenvironment.

Ibrutinib Is Effective in the Treatment of Autoimmune Haemolytic Anaemia in Mantle Cell Lymphoma

Autoimmune haemolytic anaemia (AIHA) in mantle cell lymphoma (MCL) is a rare but life-threatening complication. To date, there are no relevant data for treatment of AIHA in MCL. Ibrutinib, which has been approved for relapse/refractory MCL, is an immunomodulatory drug inhibiting Th2 activation and consequently the production of autoantibodies. We report a case of MCL with AIHA in which this form of anaemia was not controlled with the usual chemotherapy. Ibrutinib was used when MCL with AIHA relapsed, and it allowed rapid remission of AIHA and rapid discontinuation of steroid therapy.

Composite Diffuse Large B-cell and Mantle Cell Lymphoma: A Case Report

Composite lymphoma is an extremely rare clinical entity and is characterized by the presence of two different subtypes of lymphoma in the same lymph node. We report a case of composite lymphoma in a 57-year-old male presenting with leg and groin pain. The right inguinal lymph node biopsy showed large and small cells. Immunohistochemistry was consistent with large cells staining for diffuse large B-cell lymphoma (DLBCL) and small cells positive for mantle cell lymphoma (MCL). Polymerase chain reaction (PCR) analysis of immunoglobulin heavy (IGH) chain and immunoglobulin kappa (IGK) light chain gene rearrangements confirmed that the two were clonally unrelated neoplasms. There are only two reported cases of composite lymphoma with this combination in the published English literature. We report the third such case and discuss the pathology, diagnostic challenges and management of composite lymphoma.

LncRNA MALAT1 promotes development of mantle cell lymphoma by associating with EZH2

Background

Mantle cell lymphoma (MCL) is considered an aggressive subtype of non-Hodgkin’s lymphoma with variable treatment responses. There is an urgent need to identify novel markers with prognostic and therapeutic value for MCL. Long non-coding RNAs (lncRNAs) have emerged as key regulators in cancers, including MCL. Metastasis-associated lung adenocarcinoma transcript 1(MALAT1), a lncRNA located at pathognomonic translocation site of t (11; 14) of MCL. MALAT1 is known to be overexpressed in solid tumors and hematologic malignancies. However, the pathological role and clinical relevance of MALAT1 in MCL are not completely understood.

Methods

We quantified MALAT1 in MCL samples (40) and CD19+ B cells by quantitative real time polymerase chain reaction (qRT-PCR) and correlated levels with clinical outcome. We silenced MALAT1 in MCL cell lines and analyzed cells in tumorigenic assays and formation of transcription complexes.

Results

We found that the expression of MALAT1 was elevated in human MCL tumors and cell lines as compared to normal controls, and the elevated levels of MALAT1 correlated with higher MCL international prognostic index (MIPI) and reduced overall survival. MCL with knockdown of MALAT1 showed impaired cell proliferation, facilitated apoptosis and produced fewer clonogenic foci. The increased expression of p21 and p27 upon MALAT1 knockdown was regulated by enhancer of zeste homolog 2 (EZH2). Moreover, decreased phosphorylation of EZH2 at T350 attenuated the binding to MALAT1.

Conclusions

Our findings illuminate the oncogenic role of MALAT1, which may serve as a novel biomarker and as a therapeutic target in MCL.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-1100-9) contains supplementary material, which is available to authorized users.