Search

Background Treatment of newly diagnosed acute myeloid leukaemia (AML) is based on combination chemotherapy with cytarabine (ara-C) and anthracyclines. Five-year overall survival is below 30%, which has partly been attributed to cytarabine resistance. Preclinical data suggest that the addition of hydroxyurea potentiates cytarabine efficacy by increasing ara-C triphosphate (ara-CTP) levels through targeted inhibition of SAMHD1. Objectives In this phase 1 trial, we evaluated the feasibility, safety and efficacy of the addition of hydroxyurea to standard chemotherapy with cytarabine/daunorubicin in newly diagnosed AML patients. Methods Nine patients were enrolled and received at least two courses of ara-C (1 g/m(2)/2 h b.i.d. d1-5, i.e., a total of 10 g/m(2) per course), hydroxyurea (1-2 g d1-5) and daunorubicin (60 mg/m(2) d1-3). The primary endpoint was safety; secondary endpoints were complete remission rate and measurable residual disease (MRD). Additionally, pharmacokinetic studies of ara-CTP and ex vivo drug sensitivity assays were performed. Results The most common grade 3-4 toxicity was febrile neutropenia (100%). No unexpected toxicities were observed. Pharmacokinetic analyses showed a significant increase in median ara-CTP levels (1.5-fold; p = 0.04) in patients receiving doses of 1 g hydroxyurea. Ex vivo, diagnostic leukaemic bone marrow blasts from study patients were significantly sensitised to ara-C by a median factor of 2.1 (p = 0.0047). All nine patients (100%) achieved complete remission, and all eight (100%) with validated MRD measurements (flow cytometry or real-time quantitative polymerase chain reaction [RT-qPCR]) had an MRD level 1.0 x 10(9)/L and to platelet recovery >50 x 10(9)/L after the start of cycle 1 was 19 days and 22 days, respectively. Six of nine patients underwent allogeneic haematopoietic stem-cell transplantation (allo-HSCT). With a median follow-up of 18.0 (range 14.9-20.5) months, one patient with adverse risk not fit for HSCT experienced a relapse after 11.9 months but is now in second complete remission. Conclusion Targeted inhibition of SAMHD1 by the addition of hydroxyurea to conventional AML therapy is safe and appears efficacious within the limitations of the small phase 1 patient cohort. These results need to be corroborated in a larger study.

PD-1/L1 and CTLA-4 blockade immunotherapies have been approved for 13 types of cancers and are being studied in diffuse large B-cell lymphoma (DLBCL), the most common aggressive B-cell lymphoma. However, whether both PD-1 and CTLA-4 checkpoints are active and clinically significant in DLBCL is unknown. Whether PD-1 ligands expressed by tumor cells or by the microenvironment of DLBCL are critical for the PD-1 immune checkpoint is unclear. We performed immunophenotypic profiling for 405 patients with de novo DLBCL using a MultiOmyx immunofluorescence platform and simultaneously quantitated expression/coexpression of 13 immune markers to identify prognostic determinants. In both training and validation cohorts, results demonstrated a central role of the tumor immune microenvironment, and when its functionality was impaired by deficiency in tumor-infiltrating T cells and/or natural killer cells, high PD-1 expression (but not CTLA-4) on CD8+ T cells, or PD-L1 expression on T cells and macrophages, patients had significantly poorer survival after rituximab–CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) immunochemotherapy. In contrast, tumor-cell PD-L2 expression was associated with superior survival, as well as PD-L1+CD20+ cells proximal (indicates interaction) to PD-1+CD8+ T cells in patients with low PD-1+ percentage of CD8+ T cells. Gene-expression profiling results suggested the reversibility of T-cell exhaustion in PD-1+/PD-L1+ patients with unfavorable prognosis and implication of LILRA/B, IDO1, CHI3L1, and SOD2 upregulation in the microenvironment dysfunction with PD-L1 expression. This study comprehensively characterized the DLBCL immune landscape, deciphered the differential roles of various checkpoint components in rituximab–CHOP resistance in DLBCL patients, and suggests targets for PD-1/PD-L1 blockade and combination immunotherapies.

Supplementary Figures S1 to S3

Iatrogenic immunodeficiency-associated lymphoproliferative disorders (IA-LPD) may arise in patients treated with immunosuppressive drugs for autoimmune disease or other conditions. Polymorphic EBV-positive B-lymphoproliferations often have features mimicking Hodgkin lymphoma and typically a self-limited, indolent course. We present an unusual case with isolated, intracerebral manifestation of polymorphic B-LPD with features of classic Hodgkin-lymphoma in an immunosuppressed patient treated with methotrexate and infliximab, including clinical-radiological features and a detailed description of morphological findings, together with a literature review on reported cases of primary CNS manifestation of cHL and IA-LPD with Hodgkin-like morphology. The patient achieved complete remission following neurosurgery with gross total tumor resection and drug withdrawal without any additional treatment. Post-operative staging revealed no evidence for focal relapse or systemic disease during the 18 months follow-up period. Among the previously reported 24 cases of primary, isolated Hodgkin lymphoma in the central nervous system, three similar cases of iatrogenic, IA-LPDs were identified and are discussed here. Polymorphic B-LPD are destructive lesions with a range of morphologic features and disease manifestations. It is clinically important to recognize the spectrum of proliferations with features of classic Hodgkin lymphoma in immunodeficiency, iatrogenic settings, because they are likely to impact the choice of treatment strategies. Funding Agencies|Karolinska InstituteKarolinska Institutet

Supplementary Figure S1 from Activation of Mammalian Target of Rapamycin Signaling Pathway Contributes to Tumor Cell Survival in Anaplastic Lymphoma Kinase–Positive Anaplastic Large Cell Lymphoma

Reduced expression of p27 has been associated with poor prognosis in most human cancers, including pancreatic adenocarcinoma. Jun activation domain–binding protein 1 (JAB1), an activator protein (AP-1) coactivator, previously implicated in p27 degradation, is overexpressed in various tumors and correlates with low p27 expression. We examined JAB1 and p27 in normal and neoplastic pancreatic tissues. Increased JAB1 expression was seen in pancreatic carcinoma samples but not in paired normal pancreatic tissues. Immunohistochemical analysis using tissue microarrays showed that JAB1 was overexpressed in all 32 (100%) pancreatic adenocarcinoma samples tested, predominantly nuclear in 23 (72%) samples and predominantly cytoplasmic in 9 (28%) tumors. When 10% was used as a cutoff for p27 positivity, p27 was expressed in 11 (34%) of tumors; however, p27 expression was localized in the nuclei of tumor cells in only 4 (13%) of the samples. Overexpression of the JAB1 in the pancreatic carcinoma cell lines Panc-1, Mia PaCa-2, and Panc-28 resulted in decreased p27 expression. Conversely, down-regulation of JAB1 by short interfering RNA substantially increased p27 expression and inhibited progression from G1 to S phase of the cell cycle. Interestingly, JAB1-mediated p27 degradation was not impaired when S-phase kinase-interacting protein 2 (Skp2), an F-box protein required for the ubiquitination and consequent degradation of p27, was silenced. Thus, JAB1 may have an Skp2-independent p27 degradation mechanism in pancreatic cancer cells. These findings suggest that JAB1 overexpression is involved in the pathogenesis of pancreatic cancer through JAB1-mediated p27 degradation and that control of JAB1 expression is a novel therapeutic target in patients with pancreatic adenocarcinomas. (Cancer Res 2006; 66(17): 8581-9)

Anaplastic lymphoma kinase (ALK)–positive anaplastic large cell lymphoma (ALCL) frequently carries the t(2;5)(p23;q35) resulting in aberrant expression of chimeric nucleophosmin-ALK. Previously, nucleophosmin-ALK has been shown to activate phosphatidylinositol 3-kinase (PI3K) and its downstream effector, the serine/threonine kinase AKT. In this study, we hypothesized that the mammalian target of rapamycin (mTOR) pathway, which functions downstream of AKT, mediates the oncogenic effects of activated PI3K/AKT in ALK+ ALCL. Here, we provide evidence that mTOR signaling phosphoproteins, including mTOR, eukaryotic initiation factor 4E–binding protein-1, p70S6K, and ribosomal protein S6, are highly phosphorylated in ALK+ ALCL cell lines and tumors. We also show that AKT activation contributes to mTOR phosphorylation, at least in part, as forced expression of constitutively active AKT by myristoylated AKT adenovirus results in increased phosphorylation of mTOR and its downstream effectors. Conversely, inhibition of AKT expression or activity results in decreased mTOR phosphorylation. In addition, pharmacologic inhibition of PI3K/AKT down-regulates the activation of the mTOR signaling pathway. We also show that inhibition of mTOR with rapamycin, as well as silencing mTOR gene product expression using mTOR-specific small interfering RNA, decreased phosphorylation of mTOR signaling proteins and induced cell cycle arrest and apoptosis in ALK+ ALCL cells. Cell cycle arrest was associated with modulation of G1-S-phase regulators, including the cyclin-dependent kinase inhibitors p21waf1 and p27kip1. Apoptosis following inhibition of mTOR expression or function was associated with down-regulation of antiapoptotic proteins, including c-FLIP, MCL-1, and BCL-2. These findings suggest that the mTOR pathway contributes to nucleophosmin-ALK/PI3K/AKT-mediated tumorigenesis and that inhibition of mTOR represents a potential therapeutic strategy in ALK+ ALCL. (Cancer Res 2006; 66(13): 6589-97)

Langerhans cell histiocytosis (LCH) is a potentially fatal neoplasm characterized by the aberrant differentiation of mononuclear phagocytes, driven by mitogen-activated protein kinase (MAPK) pathway activation. LCH cells may trigger destructive pathology yet remain in a precarious state finely balanced between apoptosis and survival, supported by a unique inflammatory milieu. The interactions that maintain this state are not well known and may offer targets for intervention. Here, we used single-cell RNA-seq and protein analysis to dissect LCH lesions, assessing LCH cell heterogeneity and comparing LCH cells with normal mononuclear phagocytes within lesions. We found LCH discriminatory signatures pointing to senescence and escape from tumor immune surveillance. We also uncovered two major lineages of LCH with DC2- and DC3/monocyte-like phenotypes and validated them in multiple pathological tissue sites by high-content imaging. Receptor-ligand analyses and lineage tracing in vitro revealed Notch-dependent cooperativity between DC2 and DC3/monocyte lineages during expression of the pathognomonic LCH program. Our results present a convergent dual origin model of LCH with MAPK pathway activation occurring before fate commitment to DC2 and DC3/monocyte lineages and Notch-dependent cooperativity between lineages driving the development of LCH cells.