The lymph node microenvironment promotes resistance to chemotherapy in chronic lymphocytic leukemia (CLL), partly through induction of BCL2 family prosurvival proteins. Currently available inhibitors ...do not target all BCL2 family prosurvival proteins and their effectiveness is also modified by proapoptotic BCL2 homology domain 3 (BH3) only protein expression. The goal of this study was to evaluate synergy between the eIF4E/eIF4G interaction inhibitor, 4EGI-1, and the BH3 mimetic, ABT-737.
CLL cells were cultured in conditions to mimic the lymph node microenvironment. Protein synthesis and cap-complex formation were determined. Polysome association of mRNAs from BCL2 family survival genes was analyzed by translational profiling. The effects of 4EGI-1 and the BCL2/BCL2L1 antagonist, ABT-737, on CLL cell apoptosis were determined.
Protein synthesis was increased approximately 6-fold by stromal cell/CD154 culture in a phosphoinositide 3-kinase α (PI3Kα)-specific manner and was reduced by 4EGI-1. PI3K inhibitors and 4EGI-1 also reduced cap-complex formation but only 4EGI-1 consistently reduced BCL2L1 and BCL2A1 protein levels. 4EGI-1, but not PI3K inhibitors or rapamycin, induced an endoplasmic reticulum stress response including proapoptotic NOXA and the translation inhibitor phosphorylated eIF2α. 4EGI-1 and ABT-737 synergized to cause apoptosis, independent of levels of prosurvival protein expression in individual patients.
Overall protein synthesis and cap-complex formation are induced by microenvironment stimuli in CLL. Inhibition of the cap-complex was not sufficient to repress BCL2 family prosurvival expression, but 4EGI-1 inhibited BCL2A1 and BCL2L1 while inducing NOXA through cap-dependent and -independent mechanisms. 4EGI-1 and ABT-737 synergized to produce apoptosis, and these agents may be the basis for a therapeutically useful combination.
T‐cell prolymphocytic leukemia (T‐PLL) is an aggressive tumor with leukemic presentation of mature T‐lymphocytes. Here, we aimed at characterizing the initial events in the molecular pathogenesis of ...T‐PLL and particularly, at determining the point in T‐cell differentiation when the hallmark oncogenic events, that is, inv(14)(q11q32)/t(14;14)(q11;q32) and t(X;14)(q28;q11) occur. To this end, we mined whole genome and transcriptome sequencing data of 17 and 11 T‐PLL cases, respectively. Mapping of the 14q32.1 locus breakpoints identified only TCL1A, which was moreover significantly overexpressed in T‐PLL as compared to benign CD4+ and CD8+ T‐cells, as the only common oncogenic target of aberrations. In cases with t(14;14), the breakpoints mapped telomeric and in cases with inv(14) centromeric or in the 3′‐untranslated region of TCL1A. Regarding the T‐cell receptor alpha (TRA) locus‐TCL1A breakpoint junctions, all 17 breakpoints involved recombination signal sequences and 15 junctions contained nontemplated (N‐) nucleotides. All T‐PLL cases studied carried in‐frame TRA rearrangements on the intact allele, which skewed significantly toward usage of distal/central TRAV/TRAJ gene segments as compared to the illegitimate TRA rearrangements. Our findings suggest that the oncogenic TRA‐TCL1A/MTCP1 rearrangements in T‐PLL occur during opening of the TRA locus, that is, during the progression from CD4+ immature single positive to early double positive thymocyte stage, just before physiologic TCL1A expression is silenced. The cell carrying such an oncogenic event continues maturation and rearranges the second TRA allele to achieve a functional T‐cell receptor. Thereafter, it switches off RAG and DNTT expression in line with the mature T‐cell phenotype at presentation of T‐PLL.
Aberrant T-follicular helper (Tfh) cell activity is detectable in autoimmune conditions and their presence is associated with clinical outcomes when the lymph node microenvironment in B-cell ...non-Hodgkin's lymphoma is analyzed. Subsets of circulating T-follicular helper cells (cTfh), the circulating memory compartment of Tfh cells in the blood, are also perturbed in disease and therefore represent potential novel predictive biomarkers. Peripheral blood-based testing is advantageous because it is relatively non-invasive and allows simple serial monitoring.This article describes a method for isolating CD4
T-cells from human blood, and further analysis by flow-cytometry to enumerate cTfh cells and the proportions of their various subsets (cTfhPD-1
, cTfh1,2,17 and cTfh1/17). The level of these subsets was then compared between normal subjects and patients with lymphoma. We found that the method was robust enough to obtain reliable results from routinely collected patient material. The technique we describe for the analysis can be easily adapted to cell sorting and downstream applications such as RT-PCR.
Summary
Chronic lymphocytic leukaemia (CLL) cells encounter T‐cells and proliferate in response to T‐cell signals in the lymph node microenvironment. In this report we determined interleukin 21 ...(IL21) function in CLL and showed that IL21 and interleukin 4 (IL4) act co‐operatively to promote leukaemic cell proliferation without apoptosis or differentiation We further show that IL21 increased side population (SP) cells, which are associated with resistance to chemotherapy and increased self‐renewal capacity in CLL. IL21 and IL4 are the major cytokines produced by the recently described CD4+ T follicular helper (Tfh) cell subset. Determination of Tfh cells in peripheral blood showed that patients had significantly increased numbers as compared to normal subjects although no association was found between Tfh numbers and IGHV gene mutational status or clinical stage. Our data suggests that the Tfh cytokines, IL4 and IL21, contribute to driving leukaemic cell proliferation in the lymph node microenvironment, and may contribute to the specific production of cells resistant to conventional chemotherapy. We suggest that increased circulating Tfh cells is a component of T‐cell dysregulation in CLL. Our findings have implications for the therapeutic use of IL21.
Summary
BCL6 is a transcription factor that has essential B‐cell and T‐cell roles in normal antibody responses. It is involved in chromosomal translocations in diffuse large B‐cell lymphoma (DBCL; ...including primary mediastinal B‐cell lymphoma) and nodular lymphocyte predominant Hodgkin lymphoma, and is expressed in follicular lymphoma and Burkitt's lymphoma. The neoplastic T‐cells of angioimmunoblastic T‐cell lymphoma also express BCL6. BCL6 prevents terminal B‐cell differentiation largely through repression of PRDM1. In the “cell of origin” classification of DLBCL BCL6 is associated with the germinal centre subtype, which carries a good response to modern treatments. More recently, specific BCL6 antagonists, including small molecule inhibitors, have been developed. These antagonists have demonstrated that DLBCL cells, in which BCL6 is transcriptionally active, are dependent on this gene for survival. BCL6 antagonists are active against primary DLBCL and may find future application in the treatment of lymphomas.
Introduction
Brentuximab vedotin (BV)-CHP is the new standard regimen for first-line treatment of systemic anaplastic large cell lymphoma (sALCL). We undertook a retrospective analysis of consecutive ...patients diagnosed with sALCL, treated in routine practice, to serve as a benchmark analysis for comparison BV-CHP efficacy in routine practice.
Methods
Patients aged 16 years or older with sALCL treated in seven UK and Australian centres and from 14 additional centres from the UK Haematological Malignancy Research Network database (
n
= 214). Treatment allocation was clinician choice and included best supportive care (BSC). Main outcomes were time to treatment failure (TTF) and overall survival (OS). Multivariable analysis for predictors of both TTF and OS was also undertaken.
Results
The median age 52 years (range 16–93), 18% ECOG ≥ 3 and 40% of cases were ALK positive. CHOP (cyclophosphamide, adriamycin, vincristine, prednisolone) was employed in 152 (71%) of patients and CHOEP (CHOP + etoposide) in 4% of patients. For CHOP-treated patients overall response rate (ORR) was 65% and complete response (CR) 47%. Only 9% of patients underwent autologous stem cell transplant (ASCT). With 57 months median follow-up, 4-year TTF and OS were 41.2% (95% CI 33.1–49.1) and 58.9% (95% CI 50.3–66.5) respectively. Multivariable analysis showed ALK+ status was independently associated with superior TTF (HR 0.36, 95% CI 0.21–0.63) but not OS (0.44, 95% CI 0.18–1.07).
Discussion
We present a retrospective analysis with mature follow-up of one of the largest multicentre populations of sALCL available, comparable to similar large retrospective studies. ALK status remains a strong predictor of outcomes.
Conclusion
These data serve as a robust benchmark for BV-CHP as the new standard of care for sALCL. Similar real-world evidence with BV-CHP will be desirable to confirm the findings of ECHELON-2.
•Rates of bendamustine-related deaths and treatment discontinuation were similar to those reported in clinical trials.•Infections and opportunistic infections were common and often occurred long ...after completion of treatment.
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Bendamustine is among the most effective chemotherapeutics for indolent B-cell non-Hodgkin lymphomas (iNHL), but trial reports of significant toxicity, including opportunistic infections and excess deaths, led to prescriber warnings. We conducted a multicenter observational study evaluating bendamustine toxicity in real-world practice. Patients receiving at least 1 dose of bendamustine with/without rituximab (R) for iNHL were included. Demographics, lymphoma and treatment details, and grade 3 to 5 adverse events (AEs) were analyzed and correlated. In total, 323 patients were enrolled from 9 National Health Service hospitals. Most patients (96%) received bendamustine-R, and 46%, R maintenance. Overall, 21.7% experienced serious AEs (SAE) related to treatment, including infections in 12%, with absolute risk highest during induction (63%), maintenance (20%), and follow-up (17%) and the relative risk highest during maintenance (54%), induction (34%), and follow-up (28%). Toxicity led to permanent treatment discontinuation for 13% of patients, and 2.8% died of bendamustine-related infections (n = 5), myelodysplastic syndrome (n = 3), and cardiac disease (n = 1). More SAEs per patient were reported in patients with mantle cell lymphoma, poor preinduction performance status (PS), poor premaintenance PS, and abnormal preinduction total globulins and in those receiving growth factors. Use of antimicrobial prophylaxis was variable, and 3 of 10 opportunistic infections occurred despite prophylaxis. In this real-world analysis, bendamustine-related deaths and treatment discontinuation were similar to those of trial populations of younger, fitter patients. Poor PS, mantle cell histology, and maintenance R were potential risk factors. Infections, including late onset events, were the most common treatment-related SAE and cause of death, warranting extended antimicrobial prophylaxis and infectious surveillance, especially for maintenance-treated patients.
The mutational landscape of peripheral T-cell lymphoma (PTCL) is being revealed through sequencing of lymph node samples, but there has been little work on the mutational load that is present in ...cell-free DNA (cfDNA) from plasma. We report targeted sequencing of cfDNA from PTCL patients to demonstrate c.50G>T (p.Gly17Val) in RHOA as previously described in angioimmunoblastic T-cell lymphoma (AITL) and a group of PTCL not otherwise specified (NOS) but also detect novel mutations at c.73A>G (p.Phe25Leu) and c.48A>T (p.Cys16*) of exon 2, which were confirmed by Sanger sequencing. In a group of AITL and PTCL-NOS analyzed by droplet digital polymerase chain reaction, 63% (12/19) showed c.50G>T (p.Gly17Val), 53% (10/19) c.73A>G (p.Phe25Leu), and 37% (7/19) c.48A>T (pCys16*). Sequencing of lymph node tissue in 3 out of 9 cases confirmed the presence of c.73A>G (p.Phe25Leu). Inspection of individual sequencing reads from individual patients showed that a single RHOA allele could contain >1 mutation, suggesting haplotypes of mutations at RHOA. Serial sampling showed changes to RHOA mutational frequency with treatment and the apparent occurrence of clones bearing specific haplotypes associated with relapse. Therefore, sequencing of RHOA from cfDNA has revealed new mutations and haplotypes. The clinical significance of these findings will need to be explored in clinical trials, but liquid biopsy might have potential for guiding treatment decisions in PTCL.
•Multiple RHOA mutations can combine in haplotypes and are detectable in cfDNA from plasma of patients with PTCL.•Serial cfDNA monitoring of RHOA mutations could allow molecular tracking of disease response in PTCL patients undergoing treatment.
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Background Abnormally sustained immune reactions drive B-cell proliferation in some cases of marginal zone lymphoma but the CD4.sup.+ T-cell subsets, which are likely to contribute to the B-cell ...responses in the tumour microenvironment, are not well characterised and neither has the spatial distribution of the different subsets in involved lymph nodes been investigated. Methods Employing a workflow of multiplex semi-automated immunohistochemistry combined with image processing we investigated association between infiltrating T-cells and proliferating lymphoma B-cells. Results Both total numbers of activating follicular helper (Tfh) cells (defined by high expression of PD1) and suppressive regulatory (Treg) T-cells (defined by FOXP3.sup.+ expression) and the Tfh:Treg ratio, assessed over relatively large areas of tissue, varied among cases of marginal zone lymphoma. We determined spatial distribution and demonstrated that PD1.sup.hi cells showed significantly more clustering than did FOXP3.sup.+. To investigate the association of infiltrating T-cells with lymphoma B-cells we employed Pearson correlation and Morisita-Horn index, statistical measures of interaction. We demonstrated that PD1.sup.hi cells were associated with proliferating B-cells and confirmed this by nearest neighbour analysis. Conclusions The unexpected architectural complexity of T-cell infiltration in marginal zone lymphoma, revealed in this study, further supports a key role for Tfh cells in driving proliferation of lymphoma B-cells. We demonstrate the feasibility of digital analysis of spatial architecture of T-cells within marginal zone lymphoma and future studies will be needed to determine the clinical importance of these observations. Keywords: Marginal zone lymphoma, Follicular helper T-cells, Spatial characteristics
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