Targetable vulnerabilities in T- and NK-cell lymphomas identified through preclinical models.

T- and NK-cell lymphomas (TCL) are a heterogenous group of lymphoid malignancies with poor prognosis. In contrast to B-cell and myeloid malignancies, there are few preclinical models of TCLs, which has hampered the development of effective therapeutics. Here we establish and characterize preclinical models of TCL.

RET-mediated autophagy suppression as targetable co-dependence in acute myeloid leukemia.

Many cases of AML are associated with mutational activation of receptor tyrosine kinases (RTKs) such as FLT3. However, RTK inhibitors have limited clinical efficacy as single agents, indicating that AML is driven by concomitant activation of different signaling molecules. We used a functional genomic approach to identify RET, encoding an RTK, as an essential gene in multiple subtypes of AML, and observed that AML cells show activation of RET signaling via ARTN/GFRA3 and NRTN/GFRA2 ligand/co-receptor complexes.

Direct Promoter Repression by BCL11A Controls the Fetal to Adult Hemoglobin Switch.

Fetal hemoglobin (HbF, αγ) level is genetically controlled and modifies severity of adult hemoglobin (HbA, αβ) disorders, sickle cell disease, and β-thalassemia. Common genetic variation affects expression of BCL11A, a regulator of HbF silencing. To uncover how BCL11A supports the developmental switch from γ- to β- globin, we use a functional assay and protein binding microarray to establish a requirement for a zinc-finger cluster in BCL11A in repression and identify a preferred DNA recognition sequence.

Phase I trial of the mTOR inhibitor everolimus in combination with multi-agent chemotherapy in relapsed childhood acute lymphoblastic leukemia.

Background: We sought to determine the feasibility of co-administering everolimus with a four-drug reinduction in children and adolescents with acute lymphoblastic leukemia (ALL) experiencing a first marrow relapse.

Procedure: This phase I study tested everolimus with vincristine, prednisone, pegaspargase and doxorubicin in patients with marrow relapse occurring >18 months after first complete remission (CR). The primary aim was to identify the maximum tolerated dose of everolimus.

EWS-FLI1 increases transcription to cause R-loops and block BRCA1 repair in Ewing sarcoma.

Ewing sarcoma is an aggressive paediatric cancer of the bone and soft tissue. It results from a chromosomal translocation, predominantly t(11;22)(q24:q12), that fuses the N-terminal transactivation domain of the constitutively expressed EWSR1 protein with the C-terminal DNA binding domain of the rarely expressed FLI1 protein. Ewing sarcoma is highly sensitive to genotoxic agents such as etoposide, but the underlying molecular basis of this sensitivity is unclear.

Bepridil exhibits anti-leukemic activity associated with NOTCH1 pathway inhibition in chronic lymphocytic leukemia.

Dysregulated NOTCH1 signaling, by either gene mutations or microenvironment interactions, has been increasingly linked to chronic lymphocytic leukemia (CLL). Thus, inhibiting NOTCH1 activity represents a potential therapeutic opportunity for this disease. Using gene expression-based screening, we identified the calcium channel modulator bepridil as a new NOTCH1 pathway inhibitor.

Prognostic impact of kinase-activating fusions and IKZF1 deletions in pediatric high-risk B-lineage acute lymphoblastic leukemia.

Recurrent chromosomal rearrangements carry prognostic significance in pediatric B-lineage acute lymphoblastic leukemia (B-ALL). Recent genome-wide analyses identified a high-risk B-ALL subtype characterized by a diverse spectrum of genetic alterations activating kinases and cytokine receptor genes. This subtype is associated with a poor prognosis when treated with conventional chemotherapy but has demonstrated sensitivity to the relevant tyrosine kinase inhibitors.

Mapping the Mouse Cell Atlas by Microwell-Seq.

Single-cell RNA sequencing (scRNA-seq) technologies are poised to reshape the current cell-type classification system. However, a transcriptome-based single-cell atlas has not been achieved for complex mammalian systems. Here, we developed Microwell-seq, a high-throughput and low-cost scRNA-seq platform using simple, inexpensive devices.

EWS/FLI Confers Tumor Cell Synthetic Lethality to CDK12 Inhibition in Ewing Sarcoma.

Many cancer types are driven by oncogenic transcription factors that have been difficult to drug. Transcriptional inhibitors, however, may offer inroads into targeting these cancers. Through chemical genomics screening, we identified that Ewing sarcoma is a disease with preferential sensitivity to THZ1, a covalent small-molecule CDK7/12/13 inhibitor.

Predictors of Specialized Pediatric Palliative Care Involvement and Impact on Patterns of End-of-Life Care in Children With Cancer.

Purpose The impact of specialized pediatric palliative care (SPPC) teams on patterns of end-of-life care is unknown. We sought to determine (1) which children with cancer access SPPC and (2) the impact of accessing SPPC on the risk of experiencing high-intensity end-of-life care (intensive care unit admission, mechanical ventilation, or in-hospital death). Methods Using a provincial childhood cancer registry, we assembled a retrospective cohort of Ontario children with cancer who died between 2000 and 2012 and received care through pediatric institutions with an SPPC team.

Gonadal dysgenesis is associated with worse outcomes in patients with ovarian nondysgerminomatous tumors: A report of the Children's Oncology Group AGCT 0132 study.

Purpose: In this report, we characterize the timing and behavior of malignant ovarian germ cell tumors (GCTs) in pediatric patients with dysgenetic gonads compared to those with normal gonadal development.

Patients And Methods: Patients from the Children's Oncology Group AGCT0132 with malignant ovarian GCTs were included. Within this population, we sought to identify patients with gonadoblastoma, streak ovaries, or other evidence of gonadal dysgenesis (GD).

Identification of an allosteric benzothiazolopyrimidone inhibitor of the oncogenic protein tyrosine phosphatase SHP2.

The PTPN11 oncogene encodes the cytoplasmic protein tyrosine phosphatase SHP2, which, through its role in multiple signaling pathways, promotes the progression of hematological malignancies and other cancers. Here, we employ high-throughput screening to discover a lead chemical scaffold, the benzothiazolopyrimidones, that allosterically inhibits this oncogenic phosphatase by simultaneously engaging the C-SH2 and PTP domains. We improved our lead to generate an analogue that better suppresses SHP2 activity in vitro.

Outcomes of adults and children with primary mediastinal B-cell lymphoma treated with dose-adjusted EPOCH-R.

Treatment with dose-adjusted EPOCH (etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone) chemotherapy and rituximab (DA-EPOCH-R) has become the standard of care for primary mediastinal B-cell lymphoma (PMBCL) at many institutions despite limited data in the multi-centre setting. We report a large, multi-centre retrospective analysis of children and adults with PMBCL treated with DA-EPOCH-R to characterize outcomes and evaluate prognostic factors. We assessed 156 patients with PMBCL treated with DA-EPOCH-R across 24 academic centres, including 38 children and 118 adults.

Scratching the Surface of Immunotherapeutic Targets in Neuroblastoma.

In this issue of Cancer Cell, Bosse et al. report GPC2 as a therapeutic target in neuroblastoma. They show that GPC2 is selectively expressed on the cell surface of neuroblastoma and is a dependency in this disease.

Molecular pathogenesis and therapeutic implications in pediatric high-grade gliomas.

High-grade gliomas (HGG) are the most common malignant brain tumors in the pediatric population and account for a large subset of all pediatric central nervous system neoplasms. The management of pediatric HGG continues to be challenging, with poor outcome in many cases despite aggressive treatments. Consequently, parallel research efforts have been focused on identifying the underlying genetic and biological basis of pediatric HGG in order to more clearly define prognostic subgroups for treatment stratification as well as identify new treatment targets.

Rethinking childhood ependymoma: a retrospective, multi-center analysis reveals poor long-term overall survival.

Ependymoma is the third most common brain tumor in children, but there is a paucity of large studies with more than 10 years of follow-up examining the long-term survival and recurrence patterns of this disease. We conducted a retrospective chart review of 103 pediatric patients with WHO Grades II/III intracranial ependymoma, who were treated at Dana-Farber/Boston Children's Cancer and Blood Disorders Center and Chicago's Ann & Robert H. Lurie Children's Hospital between 1985 and 2008, and an additional 360 ependymoma patients identified from the Surveillance Epidemiology and End Results (SEER) database.

Super-Enhancer-Driven Transcriptional Dependencies in Cancer.

Transcriptional deregulation is one of the core tenets of cancer biology and is underpinned by alterations in both protein-coding genes and noncoding regulatory elements. Large regulatory elements, so-called super-enhancers (SEs), are central to the maintenance of cancer cell identity and promote oncogenic transcription to which cancer cells become highly addicted. Such dependence on SE-driven transcription for proliferation and survival offers an Achilles heel for the therapeutic targeting of cancer cells.

Hoxa9 and Meis1 Cooperatively Induce Addiction to Syk Signaling by Suppressing miR-146a in Acute Myeloid Leukemia.

The transcription factor Meis1 drives myeloid leukemogenesis in the context of Hox gene overexpression but is currently considered undruggable. We therefore investigated whether myeloid progenitor cells transformed by Hoxa9 and Meis1 become addicted to targetable signaling pathways. A comprehensive (phospho)proteomic analysis revealed that Meis1 increased Syk protein expression and activity.

Reduced and Compressed Cisplatin-Based Chemotherapy in Children and Adolescents With Intermediate-Risk Extracranial Malignant Germ Cell Tumors: A Report From the Children's Oncology Group.

Purpose To investigate whether event-free survival (EFS) can be maintained among children and adolescents with intermediate-risk (IR) malignant germ cell tumors (MGCT) if the administration of cisplatin, etoposide, and bleomycin (PEb) is reduced from four to three cycles and compressed from 5 to 3 days per cycle. Patients and Methods In a phase 3, single-arm trial, patients with IR MGCT (stage II-IV testicular, II-III ovarian, I-II extragonadal, or stage I gonadal tumors with subsequent recurrence) received three cycles of PEb. A parametric comparator model specified that the observed EFS rate should not be significantly < 92%.

Cbx3/HP1γ deficiency confers enhanced tumor-killing capacity on CD8 T cells.

Cbx3/HP1γ is a histone reader whose function in the immune system is not completely understood. Here, we demonstrate that in CD8 T cells, Cbx3/HP1γ insufficiency leads to chromatin remodeling accompanied by enhanced Prf1, Gzmb and Ifng expression. In tumors obtained from Cbx3/HP1γ-insufficient mice or wild type mice treated with Cbx3/HP1γ-insufficient CD8 T cells, there is an increase of CD8 effector T cells expressing the stimulatory receptor Klrk1/NKG2D, a decrease in CD4 CD25 FOXP3 regulatory T cells (Treg cells) as well as CD25 CD4 T cells expressing the inhibitory receptor CTLA4.

The creatine kinase pathway is a metabolic vulnerability in EVI1-positive acute myeloid leukemia.

Expression of the MECOM (also known as EVI1) proto-oncogene is deregulated by chromosomal translocations in some cases of acute myeloid leukemia (AML) and is associated with poor clinical outcome. Here, through transcriptomic and metabolomic profiling of hematopoietic cells, we reveal that EVI1 overexpression alters cellular metabolism. A screen using pooled short hairpin RNAs (shRNAs) identified the ATP-buffering, mitochondrial creatine kinase CKMT1 as necessary for survival of EVI1-expressing cells in subjects with EVI1-positive AML.

A molecular roadmap for induced multi-lineage trans-differentiation of fibroblasts by chemical combinations.

Recent advances have demonstrated the power of small molecules in promoting cellular reprogramming. Yet, the full potential of such chemicals in cell fate manipulation and the underlying mechanisms require further characterization. Through functional screening assays, we find that mouse embryonic fibroblast cells can be induced to trans-differentiate into a wide range of somatic lineages simultaneously by treatment with a combination of four chemicals.