The rarity of neoplastic cells in the biopsy imposes major technical hurdles that have so far limited genomic studies in classical Hodgkin lymphoma (cHL). By using a highly sensitive and robust deep next-generation sequencing approach for circulating tumor DNA (ctDNA), we aimed to identify the genetics of cHL in different clinical phases, as well as its modifications on treatment. The analysis was based on specimens collected from 80 newly diagnosed and 32 refractory patients with cHL, including longitudinal samples collected under ABVD (adriamycin, bleomycin, vinblastine, dacarbazine) chemotherapy and longitudinal samples from relapsing patients treated with chemotherapy and immunotherapy. ctDNA mirrored Hodgkin and Reed-Sternberg cell genetics, thus establishing ctDNA as an easily accessible source of tumor DNA for cHL genotyping. By identifying as the most frequently mutated gene in ∼40% of cases, we refined the current knowledge of cHL genetics. Longitudinal ctDNA profiling identified treatment-dependent patterns of clonal evolution in patients relapsing after chemotherapy and patients maintained in partial remission under immunotherapy. By measuring ctDNA changes during therapy, we propose ctDNA as a radiation-free tool to track residual disease that may integrate positron emission tomography imaging for the early identification of chemorefractory patients with cHL. Collectively, our results provide the proof of concept that ctDNA may serve as a novel precision medicine biomarker in cHL.

Purpose: Tumor-associated macrophages (TAMs) and the hyperactivation of the PI3K/AKT pathway are involved in the pathogenesis of Hodgkin lymphoma and affect disease outcome. Because the d and g isoforms of PI3K are overexpressed in Hodgkin/Reed-Sternberg (HRS) cells and the tumor microenvironment (TME), we propose that the PI3Kd/g inhibitor RP6530 might affect both HRS cells and TME, ultimately leading to an enhanced antitumor response. Experimental Design: Hodgkin lymphoma cell lines (L-540, KM-H2, and L-428) and primary human macrophages were used to investigate the activity of RP6530 in vitro and in vivo in Hodgkin lymphoma cell line xenografts. Results: In vitro, RP6530 besides killing and inhibiting the proliferation of Hodgkin lymphoma cells, downregulated lactic acid metabolism, switching the activation of macrophages from an immunosuppressive M2-like phenotype to a more inflammatory M1-like state. By RNA sequencing, we define tumor glycolysis as a specific PI3Kd/g-dependent pathway implicated in the metabolic reprogramming of cancer cells. We identify the metabolic regulator pyruvate kinase M2 as the main mediator of tumor-induced immunosuppressive phenotype of macrophages. Furthermore, we show in human tumor xenografts that RP6530 repolarizes TAMs into proinflammatory macrophages and inhibits tumor vasculature, leading to tumor regression. Interestingly, patients with Hodgkin lymphoma experiencing objective responses (complete response and partial response) in a phase I trial using RP6530 showed a significant inhibition of circulating myeloid-derived suppressor cells and an average mean reduction in serum thymus and activation-regulated chemokine levels of 40% (range, 4%-76%). Conclusions: Our results support PI3Kd/g inhibition as a novel therapeutic strategy that targets both malignant cells and the TME to treat patients with Hodgkin lymphoma.

Epigenetic changes on DNA and chromatin are implicated in cell differentiation and organogenesis. For the heart, distinct histone methylation profiles were recently linked to stage-specific gene expression programs during cardiac differentiation in vitro. However, the enzymes catalyzing these modifications and the genes regulated by them remain poorly defined. We therefore decided to identify the epigenetic enzymes that are potentially involved in cardiomyogenesis by analyzing the expression profile of the 85 genes encoding the epigenetic-related proteins in mouse cardiomyocytes (CMs), and then study how they affect gene expression during differentiation and maturation of this cell type. We show here with gene expression screening of epigenetic enzymes that the highly expressed H3 methyltransferase disruptor of telomeric silencing 1-like (DOT1L) drives a transitional pattern of di-methylation on H3 lysine 79 (H3K79) in CMs at different stages of differentiation in vitro and in vivo. Through a genome-wide chromatin-immunoprecipitation DNA-sequencing approach, we found H3K79me2 enriched at genes expressed during cardiac differentiation. Moreover, knockdown of Dot1L affected the expression of H3K79me2-enriched genes. Our results demonstrate that histone methylation, and in particular DOT1L-mediated H3K79me2 modification, drives cardiomyogenesis through the definition of a specific transcriptional landscape.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) acts as an apoptosis inducer for cancer cells sparing non-tumor cell targets. However, several phase I/II clinical trials have shown limited benefits of this molecule. In the present work, we investigated whether cell susceptibility to TRAIL ligation could be due to the presence of TRAIL death receptors (DRs) 4 and 5 in membrane microdomains called lipid rafts. We performed a series of analyses, either by biochemical methods or fluorescence resonance energy transfer (FRET) technique, on normal cells (i.e. lymphocytes, fibroblasts, endothelial cells), on a panel of human cancer B-cell lines as well as on CD19+ lymphocytes from patients with B-chronic lymphocytic leukemia, treated with different TRAIL ligands, that is, recombinant soluble TRAIL, specific agonistic antibodies to DR4 and DR5, or CD34+ TRAIL-armed cells. Irrespective to the expression levels of DRs, a molecular interaction between ganglioside GM3, abundant in lymphoid cells, and DR4 was detected. This association was negligible in all non-transformed cells and was strictly related to TRAIL susceptibility of cancer cells. Interestingly, lipid raft disruptor methyl-beta-cyclodextrin abrogated this susceptibility, whereas the chemotherapic drug perifosine, which induced the recruitment of TRAIL into lipid microdomains, improved TRAIL-induced apoptosis. Accordingly, in ex vivo samples from patients with B-chronic lymphocytic leukemia, the constitutive embedding of DR4 in lipid microdomains was associated per se with cell death susceptibility, whereas its exclusion was associated with TRAIL resistance. These results provide a key mechanism for TRAIL sensitivity in B-cell malignances: the association, within lipid microdomains, of DR4 but not DR5, with a specific ganglioside, that is the monosialoganglioside GM3. On these bases we suggest that lipid microdomains could exert a catalytic role for DR4-mediated cell death and that an ex vivo quantitative FRET analysis could be predictive of cancer cell sensitivity to TRAIL.

Relapsed/refractory Hodgkin's lymphoma (HL) is an unmet medical need requiring new therapeutic options. Interactions between the histone deacetylase inhibitor Givinostat and the RAF/MEK/ERK inhibitor Sorafenib were examined in HDLM-2 and L-540 HL cell lines. Exposure to Givinostat/Sorafenib induced a synergistic inhibition of cell growth (range, 70-80%) and a marked increase in cell death (up to 96%) due to increased H3 and H4 acetylation and strong mitochondrial injury. Gene expression profiling indicated that the synergistic effects of Givinostat/Sorafenib treatment are associated with the modulation of cell cycle and cell death pathways. Exposure to Givinostat/Sorafenib resulted in sustained production of reactive oxygen species (ROS) and activation of necroptotic cell death. The necroptosis inhibitor Necrostatin-1 prevented Givinostat/Sorafenib-induced ROS production, mitochondrial injury, activation of BH3-only protein BIM and cell death. Knockdown experiments identified BIM as a key signaling molecule that mediates Givinostat/Sorafenib-induced oxidative death of HL cells. Furthermore, in vivo xenograft studies demonstrated a 50% reduction in tumor burden (P<0.0001), a 5- to 15-fold increase in BIM expression (P < 0.0001) and a fourfold increase in tumor necrosis in Givinostat/Sorafenib-treated animals compared with mice that received single agents. These results provide a rationale for exploring Givinostat/Sorafenib combination in relapsed/refractory HL.

Although Hodgkin lymphoma (HL) is curable with current therapy, at least 20% of patients relapse or fail to make complete remission. In addition, patients who achieve long-term disease-free survival frequently undergo infertility, secondary malignancies, and cardiac failure, which are related to chemotherapeutic agents and radiation therapies. Hence, new therapeutic strategies able to counteract the HL disease in this important patient population are still a matter of study. Estrogens, in particular 17β-estradiol (E2), have been suggested to play a role in lymphoma cell homeostasis by estrogen receptors (ER) β activation. On these bases, we investigated whether the ligation of ERβ by a selective agonist, the 2,3-bis(4-hydroxyphenyl)-propionitrile (DPN), could impact HL tumor growth. We found that DPN-mediated ERβ activation led to a reduction of in vitro cell proliferation and cell cycle progression by inducing autophagy. In nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice engrafted with HL cells, ERβ activation by DPN was able to reduce lymphoma growth up to 60% and this associated with the induction of tumor cell autophagy. Molecular characterization of ERβ-induced autophagy revealed an overexpression of damage-regulated autophagy modulator 2 (DRAM2) molecule, whose role in autophagy modulation is still debated. After ERβ activation, both DRAM2 and protein 1 light chain 3 (LC3), a key actor in the autophagosome formation, strictly interacted each other and localized at mitochondrial level.Altogether these results suggest that targeting ERβ with selective agonists might affect HL cell proliferation and tumor growth via a mechanism that brings into play DRAM2-dependent autophagic cascade.

Multiple myeloma, the second most common hematologic malignancy, frequently relapses because of chemotherapeutic resistance. Fibroblast growth factors (FGF) act as proangiogenic and mitogenic cytokines in multiple myeloma. Here, we demonstrate that the autocrine FGF/FGFR axis is essential for multiple myeloma cell survival and progression by protecting multiple myeloma cells from oxidative stress-induced apoptosis. In keeping with the hypothesis that the intracellular redox status can be a target for cancer therapy, FGF/FGFR blockade by FGF trapping or tyrosine kinase inhibitor impaired the growth and dissemination of multiple myeloma cells by inducing mitochondrial oxidative stress, DNA damage, and apoptotic cell death that were prevented by the antioxidant vitamin E or mitochondrial catalase overexpression. In addition, mitochondrial oxidative stress occurred as a consequence of proteasomal degradation of the c-Myc oncoprotein that led to glutathione depletion. Accordingly, expression of a proteasomenondegradable c-Myc protein mutant was sufficient to avoid glutathione depletion and rescue the proapoptotic effects due to FGF blockade. These findings were confirmed on bortezomib-resistant multiple myeloma cells as well as on bone marrow-derived primary multiple myeloma cells from newly diagnosed and relapsed/refractory patients, including plasma cells bearing the t(4;14) translocation obtained from patients with high-risk multiple myeloma. Altogether, these findings dissect the mechanism by which the FGF/FGFR system plays a nonredundant role in multiple myeloma cell survival and disease progression, and indicate that FGF targeting may represent a therapeutic approach for patients with multiple myeloma with poor prognosis and advanced disease stage.

Because available treatments have limited efficacy in triple-negative breast cancer (TNBC), the identification of new therapeutic strategies to improve patients' outcome is urgently needed. In our study, we investigated the effects of the administration of the small molecule selective survivin suppressant YM155, alone or in association with CD341 cells transduced with a replication-deficient adenovirus encoding the human tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene (CD34-TRAIL1 cells), in three TNBC cell models. YM155 exposure significantly impaired TNBC cell growth and selectively modulated survivin expression at both mRNA and protein level. In addition, co-culturing YM155-treated TNBC cells with CD34-TRAIL1 cells resulted in markedly increased cytotoxic effect and apoptotic response in comparison with single treatments. Such a chemosensitizing effect was observed only in TNBC cells inherently expressing DR5 and relied on the ability of YM155 to upregulate DR5 expression through a p38 MAPK-and CHOP-dependent mechanism. YM155/CD34-TRAIL1 combination also showed a significant inhibitory effect on the growth of DR5-expressing TNBC cells following xenotransplantation into NOD/SCID mice, in the absence of toxicity. Overall, our data (i) provide, for the first time, evidence that YM155 sensitizes TNBC cells to CD34-TRAIL1 cells-induced apoptosis by a mechanism involving the downregulation of survivin and the simultaneous p38 MAPK-and CHOP-mediated upregulation of DR5, and (ii) suggest the combination of YM155 with TRAIL-armed CD341 progenitor cells as a promising therapeutic option for patients with TNBC expressing DR5.