Anti-CD45 PBD-based antibody-drug conjugates are effective targeted conditioning agents for gene therapy and stem cell transplant.

Stem cell gene therapy and hematopoietic stem cell transplantation (SCT) require conditioning to ablate the recipient's hematopoietic stem cells (HSCs) and create a niche for gene-corrected/donor HSCs. Conventional conditioning agents are non-specific, leading to off-target toxicities and resulting in significant morbidity and mortality. We developed tissue-specific anti-human CD45 antibody-drug conjugates (ADCs), using rat IgG2b anti-human CD45 antibody clones YTH24.

CD19/CD22 targeting with cotransduced CAR T cells to prevent antigen-negative relapse after CAR T-cell therapy for B-cell ALL.

CD19-negative relapse is a leading cause of treatment failure after chimeric antigen receptor (CAR) T-cell therapy for acute lymphoblastic leukemia. We investigated a CAR T-cell product targeting CD19 and CD22 generated by lentiviral cotransduction with vectors encoding our previously described fast-off rate CD19 CAR (AUTO1) combined with a novel CD22 CAR capable of effective signaling at low antigen density. Twelve patients with advanced B-cell acute lymphoblastic leukemia were treated (CARPALL [Immunotherapy with CD19/22 CAR Redirected T Cells for High Risk/Relapsed Paediatric CD19+ and/or CD22+ Acute Lymphoblastic Leukaemia] study, NCT02443831), a third of whom had failed prior licensed CAR therapy.

Targeting of low ALK antigen density neuroblastoma using AND logic-gate engineered CAR-T cells.

Background Aims: The targeting of solid cancers with chimeric antigen receptor (CAR) T cells faces many technological hurdles, including selection of optimal target antigens. Promising pre-clinical and clinical data of CAR T-cell activity have emerged from targeting surface antigens such as GD2 and B7H3 in childhood cancer neuroblastoma. Anaplastic lymphoma kinase (ALK) is expressed in a majority of neuroblastomas at low antigen density but is largely absent from healthy tissues.

Targeting acute myeloid cell surface using a recombinant antibody isolated from whole-cell biopanning of a phage display human scFv antibody library.

To discover new therapeutic antibodies for treatment of acute myeloid leukemia (AML) without the requirement of a known antigen, a human single-chain variable fragment (scFv) library was used to isolate novel antibody fragments recognizing HL-60 AML cells. After three rounds of biopanning, scFv-expressing phages were selected to test for binding to the target cell by flow cytometry. The clone with highest binding specificity to HL-60 cells (designated y1HL63D6) was further investigated.

Solvent-Dependent Supramolecular Host-Guest Assemblies of Platinum(II) Tweezers and a Guest System: From Discrete Molecules to High-Ordered Oligomers.

A series of platinum(II) calix[4]arene-based molecular tweezers was synthesized. The studies of the host-guest association with a charge-neutral cyclometalated platinum(II) complex showed a drastic color change and the turning on of near-infrared emission resulting from Pt⋅⋅⋅Pt and π-π interactions. Control of the host-guest assembly process by varying the solvent composition can lead to a change from discrete host and guest molecules to high-ordered host-guest oligomers with the formation of sheet-like nanostructures, demonstrating a rare example of three-state supramolecular host-guest system with high solubility in solvents of diverse polarity.

A primer set for the rapid isolation of scFv fragments against cell surface antigens from immunised rats.

Antibody phage display is a powerful platform for discovery of clinically applicable high affinity monoclonal antibodies against a broad range of targets. Libraries generated from immunized animals offer the advantage of in vivo affinity-maturation of V regions prior to library generation. Despite advantages, few studies have described isolation of antibodies from rats using immune phage display.

Enhanced CAR T cell expansion and prolonged persistence in pediatric patients with ALL treated with a low-affinity CD19 CAR.

Chimeric antigen receptor (CAR)-modified T cells targeting CD19 demonstrate unparalleled responses in relapsed/refractory acute lymphoblastic leukemia (ALL), but toxicity, including cytokine-release syndrome (CRS) and neurotoxicity, limits broader application. Moreover, 40-60% of patients relapse owing to poor CAR T cell persistence or emergence of CD19 clones. Some factors, including the choice of single-chain spacer and extracellular and costimulatory domains, have a profound effect on CAR T cell function and persistence.

Antibody Engineering & Therapeutics, the annual meeting of The Antibody Society December 7-10, 2015, San Diego, CA, USA.

The 26th Antibody Engineering & Therapeutics meeting, the annual meeting of The Antibody Society united over 800 participants from all over the world in San Diego from 6-10 December 2015. The latest innovations and advances in antibody research and development were discussed, covering a myriad of antibody-related topics by more than 100 speakers, who were carefully selected by The Antibody Society. As a prelude, attendees could join the pre-conference training course focusing, among others, on the engineering and enhancement of antibodies and antibody-like scaffolds, bispecific antibody engineering and adaptation to generate chimeric antigen receptor constructs.

Development of the designed ankyrin repeat protein (DARPin) G3 for HER2 molecular imaging.

Purpose: Human epidermal growth factor receptor-2 (HER2) overexpression is a predictor of response to anti-HER2 therapy in breast and gastric cancer. Currently, HER2 status is assessed by tumour biopsy, but this may not be representative of the larger tumour mass or other metastatic sites, risking misclassification and selection of suboptimal therapy. The designed ankyrin repeat protein (DARPin) G3 binds HER2 with high affinity at an epitope that does not overlap with trastuzumab and is biologically inert.

Tyrosine kinase inhibitor insensitivity of non-cycling CD34+ human acute myeloid leukaemia cells with FMS-like tyrosine kinase 3 mutations.

The efficacy of tyrosine kinase (TK) inhibitors on non-cycling acute myeloid leukaemia (AML) cells, previously shown to have potent tumourigenic potential, is unknown. This pilot study describes the first attempt to characterize non-cycling cells from a small series of human FMS-like tyrosine kinase 3 (FLT3) mutation positive samples. CD34+ AML cells from patients with FLT3 mutation positive AML were cultured on murine stroma.

Functional crosstalk between Bmi1 and MLL/Hoxa9 axis in establishment of normal hematopoietic and leukemic stem cells.

Bmi1 is required for efficient self-renewal of hematopoietic stem cells (HSCs) and leukemic stem cells (LSCs). In this study, we investigated whether leukemia-associated fusion proteins, which differ in their ability to activate Hox expression, could initiate leukemia in the absence of Bmi1. AML1-ETO and PLZF-RARα, which do not activate Hox, triggered senescence in Bmi1(-/-) cells.

β-Catenin mediates the establishment and drug resistance of MLL leukemic stem cells.

Identification of molecular pathways essential for cancer stem cells is critical for understanding the underlying biology and designing effective cancer therapeutics. Here, we demonstrated that β-catenin was activated during development of MLL leukemic stem cells (LSCs). Suppression of β-catenin reversed LSCs to a pre-LSC-like stage and significantly reduced the growth of human MLL leukemic cells.

A phase-advanced, extended sleep paradigm to increase sleep duration among early-morning shift workers: a preliminary investigation.

Objective: In this preliminary study, using a within-subjects design, we investigated the effects of phase-advancing bedtime on sleep quality and duration among early-morning shift workers.

Methods: The sleep-wake patterns of 16 healthy volunteers who work shifts with start times between 04.00-07.

Identification and characterization of hematopoietic stem and progenitor cell populations in mouse bone marrow by flow cytometry.

The study of key mechanisms and molecules involved in the regulation of hematopoiesis in mouse models has been greatly facilitated by multi-parameter flow cytometry. Subpopulations of hematopoietic stem and progenitor cells can be identified and characterized using this technique. Furthermore, fluorescence-activated cell sorting (FACS) can prospectively isolate functionally-defined subpopulations of hematopoietic cells for use in further in vitro or in vivo analysis.

Reconstructing the disease model and epigenetic networks for MLL-AF4 leukemia.

The lack of a proper animal model has impeded understanding of the molecular mechanism of leukemia associated with the MLL-AF4 fusion. In this issue of Cancer Cell, Krivtsov et al. report a much-improved murine Mll-AF4 model and propose a molecular link with H3K79 methylation mediated by the histone methyltransferase DOT1L.

Specific JAK2 mutation (JAK2R683) and multiple gene deletions in Down syndrome acute lymphoblastic leukemia.

Children with Down syndrome (DS) have a greatly increased risk of acute megakaryoblastic leukemia (AMKL) and acute lymphoblastic leukemia (ALL). Both DS-AMKL and the related transient myeloproliferative disorder (TMD) have GATA1 mutations as obligatory, early events. To identify mutations contributing to leukemogenesis in DS-ALL, we undertook sequencing of candidate genes, including FLT3, RAS, PTPN11, BRAF, and JAK2.

Characterization of the t(17;19) translocation by gene-specific fluorescent in situ hybridization-based cytogenetics and detection of the E2A-HLF fusion transcript and protein in patients' cells.

This is the first report to comprehensively characterize the E2A-HLF fusion generated from the t(17;19)(q22;p13) translocation in childhood B-lineage acute lymphoblastic leukemia. E2A gene rearrangement and E2A-HLF transcript and protein expression were determined using conventional cytogenetics, fluorescent in situ hybridization, reverse transcriptase polymerase chain reaction and Western blotting in leukemic cells from three patients.

E4BP4 expression is regulated by the t(17;19)-associated oncoprotein E2A-HLF in pro-B cells.

The E4BP4 basic leucine zipper (bZIP) transcription factor is regulated by interleukin-3 (IL-3) in pro-B cells and has been reported to promote survival of the murine IL-3-dependent pro-B cell lines, FL5.12 and Baf-3. The E2A-HLF oncoprotein arises from a t(17;19) translocation in childhood pro-B cell acute lymphoblastic leukaemia and acts as an anti-apoptotic factor in FL5.