The oncogenic transcription factor IRF4 is regulated by a novel CD30/NF-κB positive feedback loop in peripheral T-cell lymphoma

IL-10-mediated signals act as a switch for lymphoproliferation in Human T-cell leukemia virus type-1 infection by activating the STAT3 and IRF4 pathways

Human T-cell leukemia virus type-1 (HTLV-1) causes two distinct diseases, adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Since there are no disease-specific differences among HTLV-1 strains, the etiological mechanisms separating these respective lymphoproliferative and inflammatory diseases are not well understood. In this study, by using IL-2-dependent HTLV-1-infected T-cell lines (ILTs) established from patients with ATL and HAM/TSP, we demonstrate that the anti-inflammatory cytokine IL-10 and its downstream signals potentially act as a switch for proliferation in HTLV-1-infected cells. Among six ILTs used, ILTs derived from all three ATL patients grew much faster than those from three HAM/TSP patients. Although most of the ILTs tested produced IFN-γ and IL-6, the production of IL-10 was preferentially observed in the rapid-growing ILTs. Interestingly, treatment with exogenous IL-10 markedly enhanced proliferation of the slow-growing HAM/TSP-derived ILTs. The IL-10-mediated proliferation of these ILTs was associated with phosphorylation of STAT3 and induction of survivin and IRF4, all of which are characteristics of ATL cells. Knockdown of STAT3 reduced expression of IL-10, implying a positive-feedback regulation between STAT3 and IL-10. STAT3 knockdown also reduced survivin and IRF4 in the IL-10- producing or IL-10- treated ILTs. IRF4 knockdown further suppressed survivin expression and the cell growth in these ILTs. These findings indicate that the IL-10-mediated signals promote cell proliferation in HTLV-1-infected cells through the STAT3 and IRF4 pathways. Our results imply that, although HTLV-1 infection alone may not be sufficient for cell proliferation, IL-10 and its signaling pathways within the infected cell itself and/or its surrounding microenvironment may play a critical role in pushing HTLV-1-infected cells towards proliferation at the early stages of HTLV-1 leukemogenesis. This study provides useful information for understanding of disease mechanisms and disease-prophylactic strategies in HTLV-1 infection.

The efficacy and safety of gemcitabine, cisplatin, prednisone, thalidomide versus CHOP in patients with newly diagnosed peripheral T-cell lymphoma with analysis of biomarkers

We compared the efficacy and safety of gemcitabine, cisplatin, prednisone and thalidomide (GDPT) with standard CHOP regimen (cyclophosphamide, doxorubicin, vincristine, prednisone) for patients with newly diagnosed peripheral T-cell lymphoma (PTCL) in a prospective randomized controlled and open-label clinical trial. Between July 2010 and June 2016, 103 patients were randomly allocated into two groups, of whom 52 were treated with GDPT therapy and 51 with CHOP therapy. The 2-year progression-free survival (PFS) and overall survival (OS) rates were better in the GDPT group than in the CHOP group (57% vs. 35% for 2-year PFS, P = 0·0035; 71% vs 50% for 2-year OS, P = 0·0001). The complete remission rate (CRR) and the overall response rate (ORR) in the GDPT group were higher than in the CHOP group (52% vs. 33%, P = 0·044 for CRR; 67% vs. 49%, P = 0·046 for ORR). Haemocytopenia was the predominant adverse effect, and acute toxicity was moderate, tolerable and well managed in both arms. mRNA expression of ERCC1, RRM1, TUBB3 and TOP2A genes varied among patients but the difference did not reach statistical significance, mainly due to the relatively small sample size. The precise characters of these biomarkers remain to be identified. In conclusion, GDPT is a promising new regimen as potential first-line therapy against PTCL. This study was registered at www.clinicaltrials.gov as #NCT01664975.

IRF4/MUM1 expression is associated with poor survival outcomes in patients with peripheral T-cell lymphoma

Background: Interferon regulatory factor 4 (IRF4)/multiple myeloma oncogene-1 (MUM1) is a member of the interferon regulatory factor family of transcriptional factors. Although IRF4/MUM1 expression is associated with aggressiveness of B-cell lymphoma and multiple myeloma, the prognostic value of IRF4/MUM1 expression in peripheral T-cell lymphoma (PTCL) is unclear.

Methods: We analyzed a tissue array from 69 patients diagnosed with PTCL. The expression levels of IRF4/MUM1 and associated proteins such as MYC and Ikaros were analyzed by immunohistochemistry. Samples were classified by IRF4/MUM1 expression into a negative group (less than 5% of all tumor cells staining positive) or a positive group (≥ 5% of all tumor cells staining positive).

Results: IRF4/MUM1 expression was observed in 33% of all patients (23/69), most frequently in patients with anaplastic large cell lymphoma (ALCL, 78%, 7/9). Patients with PTCL, not otherwise specified (PTCL-NOS) and angioimmunoblastic T-cell lymphoma (AITL) showed expression rates of 33% (9/28) and 50% (4/8), respectively, whereas only 3 patients with extranodal NK/T-cell lymphoma (12%, 3/24) showed positive staining. The percentage of IRF4-positive tumor cells was significantly associated with the percentage of MYC-positive tumor cells (R: 0.410, P=0.013). Comparison of survival outcomes revealed that the IRF4/MUM1-positive group exhibited worse survival than the IRF4/MUM1-negative group; moreover, IRF4/MUM1-positive patients with a high level of MYC expression had the worst survival of all patients with nodal PTCL (PTCL-NOS, AITL, and ALCL; n=45) (P < 0.05).

Conclusions: IRF4/MUM1 expression was associated with poor survival outcomes in PTCL, implying that this gene is a potential therapeutic target.

T-Cell Lymphoma: Recent Advances in Characterization and New Opportunities for Treatment

Peripheral T-cell lymphomas (PTCLs) are uncommon, heterogeneous, and aggressive non-Hodgkin's lymphomas. Despite progress in the last several years resulting in a deeper understanding of PTCL biology and pathogenesis, there is currently no accepted single standard of care for newly diagnosed patients, and for those with relapsed or refractory disease, prognosis is dismal. The National Cancer Institute convened a Clinical Trials Planning Meeting to advance the national clinical trial agenda in lymphoma. The objective was to identify unmet needs specific to five major lymphoma subtypes and develop strategies to address them. This consensus statement reviews recent advances in the molecular and genetic characterization of PTCL that may inform novel treatments, proposes strategies to test novel therapies in the relapsed setting with the hopes of rapid advancement into frontline trials, and underscores the need for the identification and development of active and biologically rational therapies to cure PTCL at higher rates, with iterative biomarker evaluation.

PPI-G4 Glycodendrimers Upregulate TRAIL-Induced Apoptosis in Chronic Lymphocytic Leukemia Cells

Although chronic lymphocytic leukemia (CLL) is the most common adult leukemia in Western world, it remains incurable with conventional chemotherapeutic agents. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is an antitumor candidate in cancer therapy. This study examines the proapoptotic effects of poly(propylene imine) (PPI) glycodendrimers modified with the maltotriose residues (PPI-G4-OS-Mal-III and PPI-G4-DS-Mal-III) on the TNF family in CLL cells. The combination of an understanding of the signaling pathways associated with CLL and the development of a molecular profiling is a key issue for the design of personalized approaches to therapy. Gene expression is determined with two-color microarray 8 × 60K. The findings indicate that PPI-G4-OS/DS-Mal-III affect gene expression from the TRAIL apoptotic pathway and exert a strong effect on CLL cells comparable with fludarabine. Dendrimer-targeted technology may well prove to bridge the gap between the ineffective treatment of today and the effective personalized therapy of the future.

Common Genetic Polymorphisms within NFκB-Related Genes and the Risk of Developing Invasive Aspergillosis

Invasive Aspergillosis (IA) is an opportunistic infection caused by Aspergillus, a ubiquitously present airborne pathogenic mold. A growing number of studies suggest a major host genetic component in disease susceptibility. Here, we evaluated whether 14 single-nucleotide polymorphisms within NFκB1, NFκB2, RelA, RelB, Rel, and IRF4 genes influence the risk of IA in a population of 834 high-risk patients (157 IA and 677 non-IA) recruited through a collaborative effort involving the aspBIOmics consortium and four European clinical institutions. No significant overall associations between selected SNPs and the risk of IA were found in this large cohort. Although a hematopoietic stem cell transplantation (HSCT)-stratified analysis revealed that carriers of the IRF4_{rs12203592T/T} genotype had a six-fold increased risk of developing the infection when compared with those carrying the C allele (OR_REC = 6.24, 95%CI 1.25–31.2, P = 0.026), the association of this variant with IA risk did not reach significance at experiment-wide significant threshold. In addition, we found an association of the IRF4_AATC and IRF4_GGTC haplotypes (not including the IRF4_rs12203592T risk allele) with a decreased risk of IA but the magnitude of the association was similar to the one observed in the single-SNP analysis, which indicated that the haplotypic effect on IA risk was likely due to the IRF4_rs12203592 SNP. Finally, no evidence of significant interactions among the genetic markers tested and the risk of IA was found. These results suggest that the SNPs on the studied genes do not have a clinically relevant impact on the risk of developing IA.

Integrated mate-pair and RNA sequencing identifies novel, targetable gene fusions in peripheral T-cell lymphoma

Peripheral T-cell lymphomas (PTCLs) represent a heterogeneous group of T-cell malignancies that generally demonstrate aggressive clinical behavior, often are refractory to standard therapy, and remain significantly understudied. The most common World Health Organization subtype is PTCL, not otherwise specified (NOS), essentially a "wastebasket" category because of inadequate understanding to assign cases to a more specific diagnostic entity. Identification of novel fusion genes has contributed significantly to improving the classification, biologic understanding, and therapeutic targeting of PTCLs. Here, we integrated mate-pair DNA and RNA next-generation sequencing to identify chromosomal rearrangements encoding expressed fusion transcripts in PTCL, NOS. Two of 11 cases had novel fusions involving VAV1, encoding a truncated form of the VAV1 guanine nucleotide exchange factor important in T-cell receptor signaling. Fluorescence in situ hybridization studies identified VAV1 rearrangements in 10 of 148 PTCLs (7%). These were observed exclusively in PTCL, NOS (11%) and anaplastic large cell lymphoma (11%). In vitro, ectopic expression of a VAV1 fusion promoted cell growth and migration in a RAC1-dependent manner. This growth was inhibited by azathioprine, a clinically available RAC1 inhibitor. We also identified novel kinase gene fusions, ITK-FER and IKZF2-ERBB4, as candidate therapeutic targets that show similarities to known recurrent oncogenic ITK-SYK fusions and ERBB4 transcript variants in PTCLs, respectively. Additional novel and potentially clinically relevant fusions also were discovered. Together, these findings identify VAV1 fusions as recurrent and targetable events in PTCLs and highlight the potential for clinical sequencing to guide individualized therapy approaches for this group of aggressive malignancies.

NUDT2 Disruption Elevates Diadenosine Tetraphosphate (Ap4A) and Down-Regulates Immune Response and Cancer Promotion Genes

Regulation of gene expression is one of several roles proposed for the stress-induced nucleotide diadenosine tetraphosphate (Ap₄A). We have examined this directly by a comparative RNA-Seq analysis of KBM-7 chronic myelogenous leukemia cells and KBM-7 cells in which the NUDT2 Ap₄A hydrolase gene had been disrupted (NuKO cells), causing a 175-fold increase in intracellular Ap₄A. 6,288 differentially expressed genes were identified with P < 0.05. Of these, 980 were up-regulated and 705 down-regulated in NuKO cells with a fold-change ≥ 2. Ingenuity^® Pathway Analysis (IPA^®) was used to assign these genes to known canonical pathways and functional networks. Pathways associated with interferon responses, pattern recognition receptors and inflammation scored highly in the down-regulated set of genes while functions associated with MHC class II antigens were prominent among the up-regulated genes, which otherwise showed little organization into major functional gene sets. Tryptophan catabolism was also strongly down-regulated as were numerous genes known to be involved in tumor promotion in other systems, with roles in the epithelial-mesenchymal transition, proliferation, invasion and metastasis. Conversely, some pro-apoptotic genes were up-regulated. Major upstream factors predicted by IPA^® for gene down-regulation included NFκB, STAT1/2, IRF3/4 and SP1 but no major factors controlling gene up-regulation were identified. Potential mechanisms for gene regulation mediated by Ap₄A and/or NUDT2 disruption include binding of Ap₄A to the HINT1 co-repressor, autocrine activation of purinoceptors by Ap₄A, chromatin remodeling, effects of NUDT2 loss on transcript stability, and inhibition of ATP-dependent regulatory factors such as protein kinases by Ap₄A. Existing evidence favors the last of these as the most probable mechanism. Regardless, our results suggest that the NUDT2 protein could be a novel cancer chemotherapeutic target, with its inhibition potentially exerting strong anti-tumor effects via multiple pathways involving metastasis, invasion, immunosuppression and apoptosis.