Intraosseous schwannoma of the mandible: new case series, literature update, and proposal of a classification

Intraosseous schwannoma of the mandible is rare, with diagnostic and therapeutic challenges. The aims of this study were to report new cases of intraosseous schwannoma of the mandible and to propose a clinical classification, providing suggestions for treatment methods. The cases of 13 patients treated at the authors' hospital and 86 cases reported previously in the literature were reviewed. The most common clinical feature was facial swelling (60/93). The rate of cortical thinning or expansion was 44.8% (43/96); widening of the inferior alveolar nerve canal on radiographs was observed in 15 patients.

Subversion of Serotonin Receptor Signaling in Osteoblasts by Kynurenine Drives Acute Myeloid Leukemia

Remodeling of the microenvironment by tumor cells can activate pathways that favor cancer growth. Molecular delineation and targeting of such malignant-cell nonautonomous pathways may help overcome resistance to targeted therapies. Herein we leverage genetic mouse models, patient-derived xenografts, and patient samples to show that acute myeloid leukemia (AML) exploits peripheral serotonin signaling to remodel the endosteal niche to its advantage. AML progression requires the presence of serotonin receptor 1B (HTR1B) in osteoblasts and is driven by AML-secreted kynurenine, which acts as an oncometabolite and HTR1B ligand. AML cells utilize kynurenine to induce a proinflammatory state in osteoblasts that, through the acute-phase protein serum amyloid A (SAA), acts in a positive feedback loop on leukemia cells by increasing expression of IDO1-the rate-limiting enzyme for kynurenine synthesis-thereby enabling AML progression. This leukemia-osteoblast cross-talk, conferred by the kynurenine-HTR1B-SAA-IDO1 axis, could be exploited as a niche-focused therapeutic approach against AML, opening new avenues for cancer treatment.

SIGNIFICANCE

AML remains recalcitrant to treatments due to the emergence of resistant clones. We show a leukemia-cell nonautonomous progression mechanism that involves activation of a kynurenine-HTR1B-SAA-IDO1 axis between AML cells and osteoblasts. Targeting the niche by interrupting this axis can be pharmacologically harnessed to hamper AML progression and overcome therapy resistance. This article is highlighted in the In This Issue feature, p. 873.

Clinical outcomes of keratinized mucosa augmentation in jaws reconstructed with fibula or iliac bone flaps

This prospective study was undertaken to evaluate the treatment outcomes of keratinized mucosa augmentation (KMA) on the buccal and palatal/lingual sides of implants in jaws reconstructed after oncological surgery. Forty-two implants in 12 patients whose jaws had been reconstructed with a fibula or iliac bone flap were included. KMA was performed at 3 months after implant placement; this included an apically displaced partial-thickness flap and a free gingival graft (FGG) around the implants to increase the keratinized mucosa width (KMW). Patients were followed up for at least 6 months post-surgery. KMW, shrinkage, and patient pain and discomfort measured on a visual analogue scale were analysed. A histological analysis was performed of tissue epithelium from two patients. The results showed that KMW was >2 mm on both the buccal and palatal/lingual sides during follow-up. Before surgery, histological analysis showed epithelium with no epithelial spikes; normal keratinized epithelial spikes were observed at 8 weeks after KMA. Greater KMW was observed around implants in reconstructed maxillae than around those in reconstructed mandibles (P < 0.001). Patients felt more pain at the donor site than at the recipient site during the first 3 days post-surgery. KMA with FGG was predictable in reconstructed jaws and may help maintain the long-term stability of implants.

P–257 An unknown cause lead to polyspermy in IVF cycles and 0PN zygotes in ICSI cycles in male patient

Study question

The patient sperm has normal morphology and motility, which paternal factors cause the abnormal fertilization in IVF/ICSI and what is the underlying mechanism?

Summary answer

A genetic mutation of BEX1 and decreased PLC-zeta has been found in patient, which may provide novel insights of polyspermy and pronucleus formation during fertilization.

What is known already

In mammals, pronucleus formation, a landmark event for fertilization, is critical for embryonic development. Abnormal fertilization refers to the abnormal number of pronucleus and polar bodies in zygotes during in vitro fertilization, with an incidence of 5–15%, among which the incidence of polyspermy and 0PN is about 2–10% and 30%. However, the mechanisms underlying pronucleus formation still unclear. More research has focused on oocyte activation, while paternal relevant abnormal fertilizations have been rarely established. The mechanism of how sperm and/or substances carried by sperm influence the physiological process of fertilization is also unclear.

Study design, size, duration

In our study, we first work on the preliminary observation and analysis of sperm morphology, structure and sperm chromosome number, and then made further analysis at the genetic level to find out the cause of this particular phenotype in this patient. We use of zone-free golden hamster ova test the fertilizing capacity and rescue the pronucleus formation with SrCl2.

Participants/materials, setting, methods

The patient, golden hamster, Papanicolaou stain, scanning electron microscope (SEM), Transmission Electron Microscope (TEM), Fluorescence in situ hybridization (FISH), Whole Exome Sequencing (WES), IVF, ICSI, Assisted Oocyte Activation (AOA).

Main results and the role of chance

During 2016–2018, they did 4 cycle assistant reproduction technology. Cycle1, conventional IVF(C-IVF), 9 MII oocytes, 9 3PN zygotes; Cycle2, ICSI, 10 MII oocytes, 10 0PN zygotes; Cycle3, donor-oocytes C-IVF, 6 MII oocytes, 6 3PN zygotes, and the donor did C-IVF get normal zygotes and embryos; Cycle4, donor-sperm C-IVF, 7 MII oocytes, 4 2PN zygotes, 3 useable embryos. Remarkably, clinical examination about male shows normal sperm semen parameters. Papanicolaou stain and SEM shows that the sperm of the patient has normal morphology. The TEM data shows that the spermatozoa with normal head morphology and intact 9 + 2 sperm flagella structure. In the sperm FISH analysis, Chromosome ploidy is haploid. We performed WES on the male, after exclusion of frequent variants and application of technical and biological filters, two homozygous missense mutations were identified in BEX1 (c.191G&gt;A [p. W64X]), which has been few reports of male infertility. The western blot result show that the PLC-zeta was decreased in patient. After 10mM SrCl2 assisted oocyte activation, the zygote has the pronucleus formation in ICSI.

Limitations, reasons for caution

At present, we only observe sperm related factors (morphology, structure, chromosome number, genetic mutation). Next step is to detect the substances sperm carried (e.g. RNA-seq, proteomics). In this case, what is of great concern to us is the inconsistencies of the abnormal fertilization during the conventional IVF and ICSI cycles.

Wider implications of the findings: Many studies of fertilization mechanism, the main focus is on the maternal cytoplasmic factors, such as the Ca 2+ release initiate the fast block of oocytes. There are few reports about abnormal fertilization due to sperm factors. Our case may offer new insights for the study of fertilization.

Trial registration number

Not applicable

Lentiviral vector ALS20 yields high hemoglobin levels with low genomic integrations for treatment of beta-globinopathies

Ongoing clinical trials for treatment of beta-globinopathies by gene therapy involve the transfer of the beta-globin gene, which requires integration of three to four copies per genome in most target cells. This high proviral load may increase genome toxicity, potentially limiting the safety of this therapy and relegating its use to total body myeloablation. We hypothesized that introducing an additional hypersensitive site from the locus control region, the complete sequence of the second intron of the beta-globin gene, and the ankyrin insulator may enhance beta-globin expression. We identified a construct, ALS20, that synthesized significantly higher adult hemoglobin levels than those of other constructs currently used in clinical trials. These findings were confirmed in erythroblastic cell lines and in primary cells isolated from sickle cell disease patients. Bone marrow transplantation studies in beta-thalassemia mice revealed that ALS20 was curative at less than one copy per genome. Injection of human CD34⁺ cells transduced with ALS20 led to safe, long-term, and high polyclonal engraftment in xenograft experiments. Successful treatment of beta-globinopathies with ALS20 could potentially be achieved at less than two copies per genome, minimizing the risk of cytotoxic events and lowering the intensity of myeloablation.

Pathology of macrophage activation syndrome in humanized NSGS mice

"Humanized" immunodeficient mice generated via the transplantation of CD34+ human hematopoietic stem cells (hHSC) are an important preclinical model system. The triple transgenic NOD.Cg-Prkdc^scidIl2rg^tm1Wjl Tg(CMV-IL3,CSF2,KITLG)1Eav/MloySzJ (NSGS) mouse line is increasingly used as recipient for CD34+ hHSC engraftment. NSGS mice combine the features of the highly immunodeficient NSG mice with transgenic expression of the human myeloid stimulatory cytokines GM-CSF, IL-3, and Kit ligand. While generating humanized NSGS (huNSGS) mice from two independent cohorts, we encountered a fatal macrophage activation syndrome (MAS)-like phenotype resulting from the transplantation of CD34+ hHSC. huNSGS mice exhibiting this phenotype declined clinically starting at approximately 10 weeks following CD34+ hHSC engraftment, with all mice requiring euthanasia by 16 weeks. Gross changes comprised small, irregular liver, splenomegaly, cardiomegaly, and generalized pallor. Hematological abnormalities included severe thrombocytopenia and anemia. Pathologically, huNSGS spontaneously developed a disseminated histiocytosis with infiltrates of activated macrophages and hemophagocytosis predominantly affecting the liver, spleen, bone marrow, and pancreas. The infiltrates were chimeric with a mixture of human and mouse macrophages. Immunohistochemistry suggested activation of the inflammasome in both human and murine macrophages. Active Epstein-Barr virus infection was not a feature. Although the affected mice exhibited robust chimerism of the spleen and bone marrow, the phenotype often developed in the face of low chimerism of the peripheral blood. Given the high penetrance and early lethality associated with the MAS-like phenotype here described, we urge caution when considering the use of huNSGS mice for the development of long-term studies.

HIV-Resistant and HIV-Specific CAR-Modified CD4+ T Cells Mitigate HIV Disease Progression and Confer CD4+ T Cell Help In Vivo

HIV infection preferentially depletes HIV-specific CD4+ T cells, thereby impairing antiviral immunity. In this study, we explored the therapeutic utility of adoptively transferred CD4+ T cells expressing an HIV-specific chimeric antigen receptor (CAR4) to restore CD4+ T cell function to the global HIV-specific immune response. We demonstrated that CAR4 T cells directly suppressed in vitro HIV replication and eliminated virus-infected cells. Notably, CAR4 T cells containing intracellular domains (ICDs) derived from the CD28 receptor family (ICOS and CD28) exhibited superior effector functions compared to the tumor necrosis factor receptor (TNFR) family ICDs (CD27, OX40, and 4-1BB). However, despite demonstrating limited in vitro efficacy, only HIV-resistant CAR4 T cells expressing the 4-1BBζ ICD exhibited profound expansion, concomitant with reduced rebound viremia after antiretroviral therapy (ART) cessation and protection of CD4+ T cells (CAR-) from HIV-induced depletion in humanized mice. Moreover, CAR4 T cells enhanced the in vivo persistence and efficacy of HIV-specific CAR-modified CD8+ T cells expressing the CD28ζ ICD, which alone exhibited poor survival. Collectively, these studies demonstrate that HIV-resistant CAR4 T cells can directly control HIV replication and augment the virus-specific CD8+ T cell response, highlighting the therapeutic potential of engineered CD4+ T cells to engender a functional HIV cure.

Human acute myeloid leukemia blast-derived exosomes in patient-derived xenograft mice mediate immune suppression

Exosomes are virus-size membrane-bound vesicles of endocytic origin present in all body fluids. Plasma of AML patients is significantly enriched in exosomes, which carry a cargo of immunosuppressive molecules and deliver them to recipient immune cells, suppressing their functions. However, whether these exosomes originate from leukemic blasts or from various normal cells in the bone marrow or other tissues is unknown. In the current study, we developed an AML PDX model in mice and studied the molecular cargo and immune cell effects of the AML PDX exosomes in parallel with the exosomes from plasma of the corresponding AML patients. Fully engrafted AML PDX mice produced exosomes with characteristics similar to those of exosomes isolated from plasma of the AML patients who had donated the cells for engraftment. The engrafted leukemic cells produced exosomes that carried human proteins and leukemia-associated antigens, confirming the human origin of these exosomes. Furthermore, the AML-derived exosomes carried immunosuppressive proteins responsible for immune cell dysfunctions. Our studies of exosomes in AML PDX mice serve as a proof of concept that AML blasts are the source of immunosuppressive exosomes with a molecular profile that mimics the content and functions of the parental cells.

Replication study: androgen receptor splice variants determine taxane sensitivity in prostate cancer

In 2015, as part of the Prostate Cancer Foundation–Movember Foundation Reproducibility Initiative, we published a Registered Report (Shan et al., 2015) that described how we intended to replicate selected experiments from the paper “Androgen Receptor Splice Variants Determine Taxane Sensitivity in Prostate Cancer” (Thadani-Mulero et al., 2014). Here we report the results of those experiments. Growth of tumor xenografts from two prostate cancer xenograft lines, LuCaP 86.2, which expresses wild-type androgen receptor (AR) and AR variant 567, and LuCaP 23.1, which expresses wild-type AR and AR variant 7, were not affected by docetaxel treatment. The LuCaP 23.1 tumor xenografts grew slower than in the original study. This result is different from the original study, which reported significant reduction of tumor growth in the LuCaP 86.2. Furthermore, we were unable to detect ARv7 in the LuCaP 23.1, although we used the antibody as stated in the original study and ensured that it was detecting ARv7 via a known positive control (22rv1, Hörnberg et al., 2011). Finally, we report a meta-analysis of the result.

Cytokines increase engraftment of human acute myeloid leukemia cells in immunocompromised mice but not engraftment of human myelodysplastic syndrome cells

Patient-derived xenotransplantation models of human myeloid diseases including acute myeloid leukemia, myelodysplastic syndromes and myeloproliferative neoplasms are essential for studying the biology of the diseases in pre-clinical studies. However, few studies have used these models for comparative purposes. Previous work has shown that acute myeloid leukemia blasts respond to human hematopoietic cytokines whereas myelodysplastic syndrome cells do not. We compared the engraftment of acute myeloid leukemia cells and myelodysplastic syndrome cells in NSG mice to that in NSG-S mice, which have transgene expression of human cytokines. We observed that only 50% of all primary acute myeloid leukemia samples (n=77) transplanted in NSG mice provided useful levels of engraftment (>0.5% human blasts in bone marrow). In contrast, 82% of primary acute myeloid leukemia samples engrafted in NSG-S mice with higher leukemic burden and shortened survival. Additionally, all of 5 injected samples from patients with myelodysplastic syndrome showed persistent engraftment on week 6; however, engraftment was mostly low (<2%), did not increase over time, and was only transiently affected by the use of NSG-S mice. Co-injection of mesenchymal stem cells did not enhance human myelodysplastic syndrome cell engraftment. Overall, we conclude that engraftment of acute myeloid leukemia samples is more robust compared to that of myelodysplastic syndrome samples and unlike those, acute myeloid leukemia cells respond positively to human cytokines, whereas myelodysplastic syndrome cells demonstrate a general unresponsiveness to them.

Replication Study: Inhibition of BET recruitment to chromatin as an effective treatment for MLL-fusion leukaemia

In 2015, as part of the Reproducibility Project: Cancer Biology, we published a Registered Report (Fung et al., 2015), that described how we intended to replicate selected experiments from the paper "Inhibition of BET recruitment to chromatin as an effective treatment for MLL-fusion leukaemia" (Dawson et al., 2011). Here, we report the results of those experiments. We found treatment of MLL-fusion leukaemia cells (MV4;11 cell line) with the BET bromodomain inhibitor I-BET151 resulted in selective growth inhibition, whereas treatment of leukaemia cells harboring a different oncogenic driver (K-562 cell line) did not result in selective growth inhibition; this is similar to the findings reported in the original study (Figure 2A and Supplementary Figure 11A,B; Dawson et al., 2011). Further, I-BET151 resulted in a statistically significant decrease in BCL2 expression in MV4;11 cells, but not in K-562 cells; again this is similar to the findings reported in the original study (Figure 3D; Dawson et al., 2011). We did not find a statistically significant difference in survival when testing I-BET151 efficacy in a disseminated xenograft MLL mouse model, whereas the original study reported increased survival in I-BET151 treated mice compared to vehicle control (Figure 4B,D; Dawson et al., 2011). Differences between the original study and this replication attempt, such as different conditioning regimens and I-BET151 doses, are factors that might have influenced the outcome. We also found I-BET151 treatment resulted in a lower median disease burden compared to vehicle control in all tissues analyzed, similar to the example reported in the original study (Supplementary Figure 16A; Dawson et al., 2011). Finally, we report meta-analyses for each result.

Targeting Lyn regulates Snail family shuttling and inhibits metastasis

The acquisition of an invasive phenotype by epithelial cells occurs through a loss of cellular adhesion and polarity, heralding a multistep process that leads to metastatic dissemination. Since its characterization in 1995, epithelial-mesenchymal transition (EMT) has been closely linked to the metastatic process. As a defining aspect of EMT, loss of cell adhesion through downregulation of E-cadherin is carried out by several transcriptional repressors; key among them the SNAI family of transcription factors. Here we identify for the first time that Lyn kinase functions as a key modulator of SNAI family protein localization and stability through control of the Vav-Rac1-PAK1 (Vav-Rac1-p21-activated kinase) pathway. Accordingly, targeting Lyn in vitro reduces EMT and in vivo reduces metastasis of primary tumors. We also demonstrate the clinical relevance of targeting Lyn as a key player controlling EMT; patient samples across many cancers revealed a strong negative correlation between Lyn and E-cadherin, and high Lyn expression in metastatic tumors as well as metastasis-prone primary tumors. This work reveals a novel pancancer mechanism of Lyn-dependent control of EMT and further underscores the role of this kinase in tumor progression.

GRK2 desensitizes flow-induced responses in osteoblasts

Bone desensitization after mechanical loading is essential for bone to adapt to its mechanical environment. However, the desensitization mechanism is unknown. Previous studies suggest that G protein-coupled receptors (GPCRs), including P2Y and parathyroid hormone receptors, play important roles in osteoblast mechanobiology. Thus, for the present research, we examined the role of G protein-coupled receptor kinase 2 (GRK2) in osteoblast desensitization after exposure to mechanical stimulation. We first showed the existence of osteoblast desensitization after mechanical stimulation based on cytosol Ca²⁺ and phosphorylated ERK1/2 activities, detected using a fluorescent Ca²⁺-sensitive dye and western blotting, respectively. We then demonstrated that GRK2 overexpression in MC3T3-E1 cells inhibits flow-induced ERK1/2 phosphorylation, while siRNA knockdown of GRK2 enhances ERK1/2 phosphorylation. Additionally, we found that GRK2 overexpression in MC3T3-E1 cells inhibits cyclooxygenase-2 mRNA expression in the short term and alkaline phosphatase activity in the long term. More importantly, we discovered that GRK2 translocated to the cell membrane shortly after flow stimulation - a step necessary for GPCR desensitization. Previously, we have demonstrated that P2Y2 purinergic receptors, one type of GPCRs, are involved in various flow-induced osteoblastic responses. In this research, we also showed that GRK2 overexpression does not affect ATP release. Accordingly, GRK2 is able to inhibit flow-induced osteoblast responses possibly through desensitizing P2Y2 receptors.

A point-prevalence survey of healthcare-associated infection in fifty-two Chinese hospitals

BACKGROUND

Healthcare-associated infection (HCAI) represents a major problem for patient safety worldwide.

AIM

To demonstrate the prevalence, causative agents, and risk factors for HCAI in Chinese hospitals.

METHODS

A one-day point-prevalence survey was conducted in 52 Chinese hospitals between October 2014 and March 2015. A web-based software system was developed for data entry and management.

FINDINGS

Among 53,939 patients surveyed, the prevalence of patients with at least one HCAI was 3.7%. Of 2182 HCAI episodes, the most frequently occurring types were lower respiratory tract infections (47.2%), followed by urinary tract infection (12.3%), upper respiratory tract infection (11.0%), and surgical site infection (6.2%). The prevalence of patients with at least one HCAI in critical care units was highest (17.1%). Device-associated infections, including ventilator-associated pneumonia, catheter-associated urinary tract infection, and central catheter-associated bloodstream infection, accounted for only 7.9% of all HCAIs. The most frequently isolated micro-organisms were Pseudomonas aeruginosa [206 infections (9.4%)], Acinetobacter baumannii [172 infections (7.9%)], Klebsiella pneumoniae [160 infections (7.3%)], and Escherichia coli [145 infections (6.6%)]. Of the survey patients (18,206/53,939), 33.8% were receiving at least one antimicrobial agent at the time of the survey. Risk factors for HCAI included older age (≥80 years), male gender, days of hospital admission, admission into a critical care unit, and device utilization.

CONCLUSION

Our study suggests that the overall prevalence of HCAI in surveyed Chinese hospitals was lower than that reported from most European countries and the USA. More attention should be given to the surveillance and prevention of non-device-associated HCAI in China.

Abstract 4696: The LSD1 inhibitor INCB059872 is synergistic with ATRA in models of non-APL acute myelogenous leukemia

Acute myeloid leukemia (AML) is a disease characterized by the expansion of a hematopoietic stem cell like population caused in part by a block of myeloid differentiation. In AML, an altered epigenetic landscape, often arising from genetic lesions in epigenetic regulators, enforces an oncogenic expression profile and suppresses myeloid differentiation. Lysine specific demethylase 1 (LSD1) catalyzes the demethylation of lysine 4 and 9 of histone H3 through an FAD-dependent redox process. Aberrant LSD1 activity has been proposed to maintain oncogenic programs and prevent differentiation of multiple subtypes of AML. Intriguingly, recent studies indicate that LSD1 inhibition can reactivate an all-trans retinoic acid (ATRA)-dependent differentiation program in non-acute promyelocytic leukemia (APL) hematologic malignancies, a genetically heterogeneous group of blood cancers that normally respond poorly to ATRA therapy. In this study, we assessed the in vitro and in vivo effects of combining ATRA with INCB059872, a potent and selective FAD-directed LSD1 inhibitor, in non-APL AML models. As a single agent, INCB059872 induced differentiation of AML cells and when combined with ATRA, synergistically promoted differentiation as indicated by induction of CD86 and CD11b expression. In addition, the combination of INCB059872 and ATRA increased apoptosis in a panel of non-APL AML cell lines. Similarly, the combination significantly increased the fraction of CD86+CD11b+ cells and reduced cell viability in a panel of primary AML cells ex vivo. These effects in both human AML cell lines and human primary AML cells were observed across distinct FAB subtypes and genetic mutation profiles. Microarray profiling coupled with bioinformatic analysis of MV-4-11 cells demonstrated that the number of regulated genes related to differentiation and apoptotic pathways was markedly elevated in cells treated with the combination of LSD1 inhibition and ATRA relative to single agents. The synergistic increase in levels of myeloid lineage transcription factors GFI1, PU.1, CEBP and a decrease in levels of the oncogene c-MYC in the combination groups were validated by q-RT-PCR and western blot analyses. In vivo, the combination of INCB059872 and ATRA enhanced CD86 and CD11b induction and reduced tumor growth in the THP-1 xenograft model of AML compared with monotherapy. Similarly, oral administration of INCB059872 and ATRA in PDX mouse models markedly increased levels of CD11b+ cells in bone marrow. Collectively, these data underscore the synergy that can exist between LSD1 inhibition and retinoic acid receptor agonism, and provide a scientific rationale for the clinical evaluation of INCB059872 and ATRA in non-APL AML patients.

Citation Format: Min Ye, Mike Liu, Jin Lu, Yvonne Lo, Margaret Favata, Gengjie Yang, Melody Diamond, Valerie Dostalik, Paul Waeltz, Melissa Ann Fischer, Chunhong He, Liangxing Wu, Xiaochuan Shan, Hong Chang, Maryanne Covington, Yanlong Li, Tim Burn, Richard Wynn, Wenqing Yao, Gregory Hollis, Reid Huber, Peggy Scherle, Michael Savona, Martin Carroll, Bruce Ruggeri, Sang Hyun Lee. The LSD1 inhibitor INCB059872 is synergistic with ATRA in models of non-APL acute myelogenous leukemia. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4696.

Registered report: androgen receptor splice variants determine taxane sensitivity in prostate cancer

The Prostate Cancer Foundation-Movember Foundation Reproducibility Initiative seeks to address growing concerns about reproducibility in scientific research by conducting replications of recent papers in the field of prostate cancer. This Registered Report describes the proposed replication plan of key experiments from “Androgen Receptor Splice Variants Determine Taxane Sensitivity in Prostate Cancer” by Thadani-Mulero and colleagues (2014) published in Cancer Research in 2014. The experiment that will be replicated is reported in Fig. 6A. Thadani-Mulero and colleagues generated xenografts from two prostate cancer cell lines; LuCaP 86.2, which expresses predominantly the ARv567 splice variant of the androgen receptor (AR), and LuCaP 23.1, which expresses the full length AR as well as the ARv7 variant. Treatment of the tumors with the taxane docetaxel showed that the drug inhibited tumor growth of the LuCaP 86.2 cells but not of the LuCaP 23.1 cells, indicating that expression of splice variants of the AR can affect sensitivity to docetaxel. The Prostate Cancer Foundation-Movember Foundation Reproducibility Initiative is a collaboration between the Prostate Cancer Foundation, the Movember Foundation and Science Exchange, and the results of the replications will be published by PeerJ.

Registered report: Inhibition of BET recruitment to chromatin as an effective treatment for MLL-fusion leukemia

The Reproducibility Project: Cancer Biology seeks to address growing concerns about reproducibility in scientific research by conducting replications of selected experiments from a number of high-profile papers in the field of cancer biology. The papers, which were published between 2010 and 2012, were selected on the basis of citations and Altmetric scores (Errington et al., 2014). This Registered report describes the proposed replication plan of key experiments from ‘Inhibition of bromodomain and extra terminal (BET) recruitment to chromatin as an effective treatment for mixed-lineage leukemia (MLL)-fusion leukemia’ by Dawson and colleagues, published in Nature in 2011 (Dawson et al., 2011). The experiments to be replicated are those reported in Figures 2A, 3D, 4B, 4D and Supplementary Figures 11A-B and 16A. In this study, BET proteins were demonstrated as potential therapeutic targets for modulating aberrant gene expression programs associated with MLL-fusion leukemia. In Figure 2A, the BET bromodomain inhibitor I-BET151 was reported to suppress growth of cells harboring MLL-fusions compared to those with alternate oncogenic drivers. In Figure 3D, treatment of MLL-fusion leukemia cells with I-BET151 resulted in transcriptional suppression of the anti-apoptotic gene BCL2. Figures 4B and 4D tested the therapeutic efficacy of I-BET151 in vivo using mice injected with human MLL-fusion leukemia cells and evaluated disease progression following I-BET151 treatment. The Reproducibility Project: Cancer Biology is a collaboration between the Center for Open Science and Science Exchange and the results of the replications will be published in eLife.

DOI:http://dx.doi.org/10.7554/eLife.08997.001

Abstract 2470: Anti-leukemic activity and tolerability of anti-human CD47 monoclonal antibodies

CD47 is a ubiquitously expressed cell surface Ig superfamily member. CD47 mediates a variety of biological processes, including leukocyte adhesion/migration, T-cell activation, apoptosis, and phagocytosis due to physical interaction with various proteins (integrins, thrombospondin-1, and signal regulatory protein alpha [SIRPα]). The CD47-SIRPα interaction negatively regulates phagocytosis.

Enhanced CD47 expression has been described on hematological and solid cancers, suggesting that CD47 may mediate cancer cell escape from immune surveillance (e.g., by macrophages or neutrophils). Published studies demonstrated that anti-CD47 antibodies induced phagocytosis or apoptosis of cancer cells in vitro and mediated in vivo anti-tumor efficacy.

Hypothesizing that blocking the CD47-SIRPα interaction will lead to phagocytosis and elimination of tumor cells, we generated 23 unique anti-CD47 monoclonal antibodies (mAbs), which potently block the CD47-SIRPα interaction. Upon further functional testing and optimization, three candidates emerged with nanomolar affinity to human and cynomolgus monkey CD47 and lack of hemagglutination and platelet aggregation activity: C47B157, C47B161 and C47B222 (human CD47 KD 3.53, 2.87, and 1.12 nM, respectively). To further characterize these antibodies and to better understand the contribution of merely blocking the CD47-SIRPα interaction to in vitro and in vivo anti-tumor activity, the mAbs were cloned into an effector function silent (IgG2sigma) and competent (IgG1) Fc backbone. In vitro ADCP assays demonstrated that IgG1 C47B157, C47B161, and C47B222 enhanced phagocytosis 4-fold over PBS control, while the IgG2sigma mAbs did not enhance phagocytosis. Subsequently, the anti-tumor activity was characterized in three human acute myeloid leukemia (AML) xenograft models (HL60/NSG, MV4-11/NSG, and Kasumi-3/NSG mice). At 10mg/kg C47B157, C47B161, and C47B222 completely suppressed growth of leukemia cells across all models in peripheral blood as IgG1 (0.74-2.78%) vs. control (23.2-88.5%) at time of control sacrifice. As IgG2sigma, C47B222 caused greatest suppression at 10 mg/kg in all models (1.6-2.2%). Additional in vivo studies with either AML cell lines or AML patient-derived primary cells revealed that although IgG2sigma C47B222 reduced disease outgrowth in peripheral blood and distinct organs (e.g., spleen), merely blocking the CD47-SIRPα interaction did not yield a survival advantage. In non-human primates, a single dose of IgG1 C47B222 caused ∼40% decrease in red blood cell count, hematocrit and hemoglobin at 1 mg/kg. In contrast, IgG2sigma C47B222 had minimal impact on red cell indices at 1 and 10 mg/kg.

In conclusion, the findings suggest that efficacy and tolerability of anti-CD47 mAbs are Fc effector function dependent. The need to balance efficacy and tolerability raise questions on the feasibility of targeting CD47 in the development of cancer therapeutics.

Citation Format: E. Christine Pietsch, Jianying Dong, Xiaochun Zhang, Diana Chin, Rebecca Hawkins, Thai Dinh, Mimi Zhou, Brandy Strake, Ping-Hua Feng, Meredith Rocca, Cedric Dos Santos, Xiaochuan Shan, Gwenn Danet-Desnoyers, Elizabeth Kaiser, Hillary Quinn, Jeffrey A. Nemeth, Ricardo Attar. Anti-leukemic activity and tolerability of anti-human CD47 monoclonal antibodies. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2470. doi:10.1158/1538-7445.AM2015-2470

Rip3 knockdown rescues photoreceptor cell death in blind pde6c zebrafish

Achromatopsia is a progressive autosomal recessive retinal disease characterized by early loss of cone photoreceptors and later rod photoreceptor loss. In most cases, mutations have been identified in CNGA3, CNGB3, GNAT2, PDE6C or PDE6H genes. Owing to this genetic heterogeneity, mutation-independent therapeutic schemes aimed at preventing cone cell death are very attractive treatment strategies. In pde6c(w59) mutant zebrafish, cone photoreceptors expressed high levels of receptor-interacting protein kinase 1 (RIP1) and receptor-interacting protein kinase 3 (RIP3) kinases, key regulators of necroptotic cell death. In contrast, rod photoreceptor cells were alternatively immunopositive for caspase-3 indicating activation of caspase-dependent apoptosis in these cells. Morpholino gene knockdown of rip3 in pde6c(w59) embryos rescued the dying cone photoreceptors by inhibiting the formation of reactive oxygen species and by inhibiting second-order neuron remodelling in the inner retina. In rip3 morphant larvae, visual function was restored in the cones by upregulation of the rod phosphodiesterase genes (pde6a and pde6b), compensating for the lack of cone pde6c suggesting that cones are able to adapt to their local environment. Furthermore, we demonstrated through pharmacological inhibition of RIP1 and RIP3 activity that cone cell death was also delayed. Collectively, these results demonstrate that the underlying mechanism of cone cell death in the pde6c(w59) mutant retina is through necroptosis, whereas rod photoreceptor bystander death occurs through a caspase-dependent mechanism. This suggests that targeting the RIP kinase signalling pathway could be an effective therapeutic intervention in retinal degeneration patients. As bystander cell death is an important feature of many retinal diseases, combinatorial approaches targeting different cell death pathways may evolve as an important general principle in treatment.

A novel allele, HLA-A*03:01:09, identified by sequence-based typing in a Chinese individual

We describe the identification of a novel allele HLA-A*03:01:09 in a Chinese individual.

Identification of the novel HLA-B allele, HLA-B*39:42, in a Chinese individual

The HLA-B*39:42 allele differs from the closest matching allele B*39:01:01:01 by two nucleotide substitutions in exon 3.

HLA-B*27:44, a novel allele identified by sequence-based typing, is a well-documented allele in China

The sequence of HLA-B*27:44 differs in exon 2 from the sequence of B*27:08 by one amino acid change at codon 74.

A novel HLA-B allele, B*40:01:06, identified by sequence-based typing in a Chinese individual

The sequence of HLA-B*40:01:06 differs in exon 3 from the sequence of B*40:01:01 by one nucleotide 435 (codon121) G to A.

A novel HLA-B allele, B*07:55, identified by sequence-based typing

The novel allele differs from HLA-B*07:02:01 by a single nucleotide substitution at position 538 in exon 3.

Identification of a novel HLA-A allele, A*24:128 in a Chinese individual

The novel HLA-A*24:128 shows one nucleotide change from HLA-A*24:02:01:01 in exon 2 at position 155 from A to G.

A novel HLA-A allele, A*24:02:17, identified by sequence-based typing

The A*24:02:17 allele differs from the most close matching allele A*24:02:01:01 by one nucleotide substitution in exon 2, at position 264.

A novel HLA-B allele, B*13:18, identified by sequence-based typing

The B*13:18 allele differs from the most closely matching allele B*13:02:01 by one nucleotide substitution in exon 3, at position 539.