The repertoire and structure of adhesion GPCR transcript variants assembled from publicly available deep-sequenced human samples

Alternative splicing and multiple transcription start and termination sites can produce a diverse repertoire of mRNA transcript variants from a given gene. While the full picture of the human transcriptome is still incomplete, publicly available RNA datasets have enabled the assembly of transcripts. Using publicly available deep sequencing data from 927 human samples across 48 tissues, we quantified known and new transcript variants, provide an interactive, browser-based application Splice-O-Mat and demonstrate its relevance using adhesion G protein-coupled receptors (aGPCRs) as an example. On average, 24 different transcript variants were detected for each of the 33 human aGPCR genes, and several dominant transcript variants were not yet annotated. Variable transcription starts and complex exon-intron structures encode a flexible protein domain architecture of the N- and C termini and the seven-transmembrane helix domain (7TMD). Notably, we discovered the first GPCR (ADGRG7/GPR128) with eight transmembrane helices. Both the N- and C terminus of this aGPCR were intracellularly oriented, anchoring the N terminus in the plasma membrane. Moreover, the assessment of tissue-specific transcript variants, also for other gene classes, in our application may change the evaluation of disease-causing mutations, as their position in different transcript variants may explain tissue-specific phenotypes.

The dark sides of the GPCR tree - research progress on understudied GPCRs

A large portion of the human GPCRome is still in the dark and understudied, consisting even of entire subfamilies of GPCRs such as odorant receptors, class A and C orphans, adhesion GPCRs, Frizzleds and taste receptors. However, it is undeniable that these GPCRs bring an untapped therapeutic potential that should be explored further. Open questions on these GPCRs span diverse topics such as deorphanisation, the development of tool compounds and tools for studying these GPCRs, as well as understanding basic signalling mechanisms. This review gives an overview of the current state of knowledge for each of the diverse subfamilies of understudied receptors regarding their physiological relevance, molecular mechanisms, endogenous ligands and pharmacological tools. Furthermore, it identifies some of the largest knowledge gaps that should be addressed in the foreseeable future and lists some general strategies that might be helpful in this process.

The N Terminus of Adhesion G Protein–Coupled Receptor GPR126/ADGRG6 as Allosteric Force Integrator

The adhesion G protein–coupled receptor (aGPCR) GPR126/ADGRG6 plays an important role in several physiological functions, such as myelination or peripheral nerve repair. This renders the receptor an attractive pharmacological target. GPR126 is a mechano-sensor that translates the binding of extracellular matrix (ECM) molecules to its N terminus into a metabotropic intracellular signal. To date, the structural requirements and the character of the forces needed for this ECM-mediated receptor activation are largely unknown. In this study, we provide this information by combining classic second-messenger detection with single-cell atomic force microscopy. We established a monoclonal antibody targeting the N terminus to stimulate GPR126 and compared it to the activation through its known ECM ligands, collagen IV and laminin 211. As each ligand uses a distinct mode of action, the N terminus can be regarded as an allosteric module that can fine-tune receptor activation in a context-specific manner.

Abstract 2866: BAY 3375968: An afucosylated anti-CCR8 antibody depleting activated intratumoral regulatory T cells as a cancer immunotherapy

Regulatory T cells (Tregs) play an indispensable role in mediating peripheral tolerance to self-antigens. They can also promote tumor growth by suppressing the function of effector CD8+ and CD4+ T cells in the tumor microenvironment (TME). Furthermore, Tregs are identified as one of the key resistance mechanisms hampering the efficacy of immune checkpoint inhibitors (ICIs) across many tumor types. Therefore, there is a high need for safe and effective agents that would specifically deplete tumor-infiltrating Tregs while sparing both peripheral Tregs and effector T cells.

Chemokine receptor 8 (CCR8) is predominantly expressed on activated tumor-infiltrating Tregs and marks the most suppressive and proliferative Treg population. CCR8+ Tregs are associated with high tumor grade and poor overall survival across many tumor types such as lung, breast, or head-neck cancer. Thus, unlike other approaches directed against Tregs, targeting CCR8 offers the opportunity to specifically deplete intra-tumoral Tregs without impacting peripheral Tregs or other immune cells.

BAY 3375968 is a non-internalizing fully human glycoengineered (afucosylated) monoclonal IgG1 antibody, which in vitro selectively depleted human CCR8+ Tregs via antibody dependent cellular cytotoxicity (ADCC) and antibody dependent cellular phagocytosis (ADCP). In vivo efficacy studies using mouse surrogate antibodies showed strong monotherapeutic efficacy across a variety of murine tumor models with clear correlation of intratumoral CCR8+ Treg depletion and CD8+ T cell increase. The monotherapeutic efficacy of CCR8 depleting antibodies was further enhanced by combinations with ICIs. BAY 3375968 also showed a good safety profile in cynomolgus monkeys. In conclusion, CCR8 is a novel Treg depleting immunotherapy target, and due to its highly tumor-restricted expression profile, BAY 3375968 may provide superior clinical safety and efficacy profile comparing to other less specific Treg targeting approaches.

Based on the promising pre-clinical data, preparations for a phase I clinical trial investigating the safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary anti-tumor activity of BAY 3375968 are underway.

Citation Format: Helge Roider, Su-Yi Tseng, Sabine Hoff, Sandra Berndt, Katharina Filarski, Uwe Gritzan, Beatrix Stelte-Ludwig, Wiebke M. Nadler, Joanna Grudzinska-Goebel, Philipp Ellinger, Mark Trautwein, Matyas Gorjanacz. BAY 3375968: An afucosylated anti-CCR8 antibody depleting activated intratumoral regulatory T cells as a cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2866.

A Novel NAMPT Inhibitor-Based Antibody-Drug Conjugate Payload Class for Cancer Therapy

Inhibition of intracellular nicotinamide phosphoribosyltransferase (NAMPT) represents a new mode of action for cancer-targeting antibody-drug conjugates (ADCs) with activity also in slowly proliferating cells. To extend the repertoire of available effector chemistries, we have developed a novel structural class of NAMPT inhibitors as ADC payloads. A structure-activity relationship-driven approach supported by protein structural information was pursued to identify a suitable attachment point for the linker to connect the NAMPT inhibitor with the antibody. Optimization of scaffolds and linker structures led to highly potent effector chemistries which were conjugated to antibodies targeting C4.4a (LYPD3), HER2 (c-erbB2), or B7H3 (CD276) and tested on antigen-positive and -negative cancer cell lines. Pharmacokinetic studies, including metabolite profiling, were performed to optimize the stability and selectivity of the ADCs and to evaluate potential bystander effects. Optimized NAMPTi-ADCs demonstrated potent in vivo antitumor efficacy in target antigen-expressing xenograft mouse models. This led to the development of highly potent NAMPT inhibitor ADCs with a very good selectivity profile compared with the corresponding isotype control ADCs. Moreover, we demonstrate─to our knowledge for the first time─the generation of NAMPTi payload metabolites from the NAMPTi-ADCs in vitro and in vivo. In conclusion, NAMPTi-ADCs represent an attractive new payload class designed for use in ADCs for the treatment of solid and hematological cancers.

Antibody–drug conjugates harboring a kinesin spindle protein inhibitor with immunostimulatory properties

Antibody–drug conjugates (ADCs) are used to target cancer cells by means of antibodies directed to tumor-associated antigens, causing the incorporation of a cytotoxic payload into target cells. Here, we characterized the mode of action of ADC costing of a TWEAKR-specific monoclonal antibody conjugated to a small molecule kinesin spindle protein (KSP) inhibitor (KSPi). These TWEAKR-KSPi-ADCs showed strong efficacy in a TWEAKR expressing CT26 colon cancer model in mice. TWEAKR-KSPi-ADCs controlled the growth of CT26 colon cancers in immunodeficient as well as in immunocompetent mice. However, when treated with suboptimal doses, TWEAKR-KSPi-ADCs were still active in immunocompetent but not in immunodeficient mice, indicating that TWEAKR-KSPi-ADCs act – in addition to the cytotoxic mode of action – through an immunological mechanism. Indeed, in vitro experiments performed with a cell-permeable small molecule KSPi closely related to the active payload released from the TWEAKR-KSPi-ADCs revealed that KSPi was capable of stimulating several hallmarks of immunogenic cell death (ICD) on three different human cancer cell lines: cellular release of adenosine triphosphate (ATP) and high mobility group B1 protein (HMGB1), exposure of calreticulin on the cell surface as well as a transcriptional type-I interferon response. Further, in vivo experiments confirmed that treatment with TWEAKR-KSPi-ADCs activated immune responses via enhancing the infiltration of CD4⁺ and CD8⁺ T lymphocytes in tumors and the local production of interferon-γ, interleukin-2, and tumor necrosis factor-α. In conclusion, the antineoplastic effects of TWEAKR-KSPi-ADCs can partly be attributed to its ICD-stimulatory properties.

A Model for the Signal Initiation Complex Between Arrestin-3 and the Src Family Kinase Fgr

Arrestins regulate a wide range of signaling events, most notably when bound to active G protein-coupled receptors (GPCRs). Among the known effectors recruited by GPCR-bound arrestins are Src family kinases, which regulate cellular growth and proliferation. Here, we focus on arrestin-3 interactions with Fgr kinase, a member of the Src family. Previous reports demonstrated that Fgr exhibits high constitutive activity, but can be further activated by both arrestin-dependent and arrestin-independent pathways. We report that arrestin-3 modulates Fgr activity with a hallmark bell-shaped concentration-dependence, consistent with a role as a signaling scaffold. We further demonstrate using NMR spectroscopy that a polyproline motif within arrestin-3 interacts directly with the SH3 domain of Fgr. To provide a framework for this interaction, we determined the crystal structure of the Fgr SH3 domain at 1.9 Å resolution and developed a model for the GPCR-arrestin-3-Fgr complex that is supported by mutagenesis. This model suggests that Fgr interacts with arrestin-3 at multiple sites and is consistent with the locations of disease-associated Fgr mutations. Collectively, these studies provide a structural framework for arrestin-dependent activation of Fgr.

Immunostimulatory effects of targeted thorium-227 conjugates as single agent and in combination with anti-PD-L1 therapy

Background

Targeted thorium-227 conjugates (TTCs) are an emerging class of targeted alpha therapies (TATs). Their unique mode of action (MoA) is the induction of difficult-to-repair clustered DNA double-strand breaks. However, thus far, their effects on the immune system are largely unknown. Here, we investigated the immunostimulatory effects of the mesothelin-targeted thorium-227 conjugate (MSLN-TTC) in vitro and in vivo in monotherapy and in combination with an inhibitor of the immune checkpoint programmed death receptor ligand 1 (PD-L1) in immunocompetent mice.

Methods

The murine cell line MC38 was transfected with the human gene encoding for MSLN (hMSLN) to enable binding of the non-cross-reactive MSLN-TTC. The immunostimulatory effects of MSLN-TTC were studied in vitro on human cancer cell lines and MC38-hMSLN cells. The efficacy and MoA of MSLN-TTC were studied in vivo as monotherapy or in combination with anti-PD-L1 in MC38-hMSLN tumor-bearing immunocompetent C57BL/6 mice. Experiments were supported by RNA sequencing, flow cytometry, immunohistochemistry, mesoscale, and TaqMan PCR analyses to study the underlying immunostimulatory effects. In vivo depletion of CD8+ T cells and studies with Rag2/Il2Rg double knockout C57BL/6 mice were conducted to investigate the importance of immune cells to the efficacy of MSLN-TTC.

Results

MSLN-TTC treatment induced upregulation of DNA sensing pathway transcripts (IL-6, CCL20, CXCL10, and stimulator of interferon genes (STING)-related genes) in vitro as determined by RNASeq analysis. The results, including phospho-STING activation, were confirmed on the protein level. Danger-associated molecular pattern molecules were upregulated in parallel, leading to dendritic cell (DC) activation in vitro. MSLN-TTC showed strong antitumor activity (T:C 0.38, p<0.05) as a single agent in human MSLN-expressing MC38 tumor-bearing immunocompetent mice. Combining MSLN-TTC with anti-PD-L1 further enhanced the efficacy (T:C 0.08, p<0.001) as evidenced by the increased number of tumor-free surviving animals. MSLN-TTC monotherapy caused migration of CD103+ cDC1 DCs and infiltration of CD8+ T cells into tumors, which was enhanced on combination with anti-PD-L1. Intriguingly, CD8+ T-cell depletion decreased antitumor efficacy.

Conclusions

These in vitro and in vivo data on MSLN-TTC demonstrate that the MoA of TTCs involves activation of the immune system. The findings are of relevance for other targeted radiotherapies and may guide clinical combination strategies.

Abstract 1722: Enhancement of anti-tumor T-cell immunity by means of an oral small molecule targeting the intracellular immune checkpoint MAP4K1

Immune checkpoint blockade using antibodies targeting the cell surface expressed proteins CTLA-4, PD-1 and PD-L1 has revolutionized cancer care and its clinical impact in several indications has prompted a search for complementary immunostimulatory approaches that can further increase the efficacy of these drugs. Mitogen-activated protein kinase kinase kinase kinase 1 (MAP4K1; HPK1), a serine/threonine kinase expressed exclusively in hematopoietic cell lineages, mediates a negative feedback signal downstream of T-cell receptor stimulation. Its activity is enhanced by PGE2 and TGFβ, factors commonly present in the tumor microenvironment. Mice deficient for MAP4K1 or expressing a kinase-dead variant of MAP4K1 exhibit enhanced T-cell function, including increased anti-tumor immunity. We developed the small molecule inhibitor BAY-405 that displays potent nanomolar MAP4K1 inhibition in biochemical and cellular assays, good kinase selectivity, and in vivo exposure after oral dosing. Pharmacological inhibition of MAP4K1 enhances T-cell immunity and overcomes the suppressive impact of PGE2, TGFβ and CD4+ T-regulatory cells. Single agent treatment of tumor-bearing mice results in suppression of tumor outgrowth in several syngeneic models. This is accompanied by an increase in the anti-tumor T-cell response, dependent on an intact T-cell compartment, while not involving direct anti-tumor cytotoxicity. Inhibition of MAP4K1 in conjunction with PD-L1 blockade results in further suppression of tumor outgrowth. Moreover, we found that MAP4K1 is expressed in both PD-L1-high and PD-L1-low human cancers. In summary, our data show that selective inhibition of MAP4K1 by means of small molecule drugs may be used to expand the patient population responding to immune checkpoint inhibition.

Citation Format: Gabriele Leder, Rafael Carretero, Jeffrey Mowat, Sandra Berndt, Roland Neuhaus, Nuria Aiguabella Font, Ulf Boemer, Oliver von Ahsen, Uwe Eberspaecher, Judith Guenther, Mareike Grees, Corinna Link, Barbara Nicke, Daniel Baumann, Martina Schaefer, Mine Oezcan-Wahlbrink, Nicolas D. Werbeck, Ingo Hartung, Bertolt Kreft, Rienk Offringa. Enhancement of anti-tumor T-cell immunity by means of an oral small molecule targeting the intracellular immune checkpoint MAP4K1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1722.

An Eight Amino Acid Segment Controls Oligomerization and Preferred Conformation of the two Non-visual Arrestins

G protein coupled receptors signal through G proteins or arrestins. A long-standing mystery in the field is why vertebrates have two non-visual arrestins, arrestin-2 and arrestin-3. These isoforms are ~75% identical and 85% similar; each binds numerous receptors, and appear to have many redundant functions, as demonstrated by studies of knockout mice. We previously showed that arrestin-3 can be activated by inositol-hexakisphosphate (IP₆). IP₆ interacts with the receptor-binding surface of arrestin-3, induces arrestin-3 oligomerization, and this oligomer stabilizes the active conformation of arrestin-3. Here, we compared the impact of IP₆ on oligomerization and conformational equilibrium of the highly homologous arrestin-2 and arrestin-3 and found that these two isoforms are regulated differently. In the presence of IP₆, arrestin-2 forms "infinite" chains, where each promoter remains in the basal conformation. In contrast, full length and truncated arrestin-3 form trimers and higher-order oligomers in the presence of IP₆; we showed previously that trimeric state induces arrestin-3 activation (Chen et al., 2017). Thus, in response to IP₆, the two non-visual arrestins oligomerize in different ways in distinct conformations. We identified an insertion of eight residues that is conserved across arrestin-2 homologs, but absent in arrestin-3 that likely accounts for the differences in the IP₆ effect. Because IP₆ is ubiquitously present in cells, this suggests physiological consequences, including differences in arrestin-2/3 trafficking and JNK3 activation. The functional differences between two non-visual arrestins are in part determined by distinct modes of their oligomerization. The mode of oligomerization might regulate the function of other signaling proteins.

Abstract 1807: Anti-tumor activity of a novel structural class of NAMPT inhibitor-based ADCs in models of hematologic and solid tumor indications

Nicotinamide phosphoribosyl-transferase (NAMPT) is the rate-limiting enzyme in the salvage pathway, generating nicotinamide adenine dinucleotide (NAD) from nicotinamide (NAM). Inhibition of intracellular NAMPT activity represents a differentiated mode-of-action for tumor-targeting antibody-drug conjugates (ADCs) as it is not dependent on cell proliferation. Thus, NAMPT inhibitor-based ADCs have the potential to target both proliferating and resting tumor cells. We therefore developed a novel structural class of NAMPT inhibitors (NAMPTi) as a potent ADC payload class and characterized NAMPTi and NAMPTi-ADCs in vitro and in vivo in preclinical tumor models. We profiled the small molecule NAMPTi BAY-346 in comparison to the kinesin spindle protein inhibitor (KSPi) BAY-331 on a panel of 350 cancer cell lines from various tumor indications showing a differential sensitivity profile of BAY-346 vs BAY-331, with cell lines characterized by low NAMPT mRNA levels as being very sensitive to BAY-346. NAMPTi BAY-346, but not KSPi BAY-331, reduced the viability of quiescent HaCat cells as well as of serum starved non-proliferating NCI-N87 cells. In vitro treatment with NAMPTi BAY-346, which bears a pyridine warhead that can be phosphoribosylated by NAMPT, resulted in IC50 values in the nanomolar to subnanomolar range (2.8 nM to 0.01 nM) in cell lines derived from solid and hematologic tumor indications (e.g., THP-1, MV-4-11, U-251, NCI-H292, MDA-MB-453, LoVo, KPL4, HT1197 and BxPC3). BAY-346 was 100-fold more potent than the small molecule NAMPTi BAY-248, which cannot be phosphoribosylated. A BAY-346 derived NAMPTi was conjugated as a payload to a series of antibodies targeting different tumor-associated antigens: C4.4a (LYPD3), HER2, B7H3 (CD276), and TWEAKR (Fn14/ TNFRSF10A). The resulting NAMPTi-ADCs were tested in proliferation and cellular mechanistic in vitro assays. NAMPTi-ADCs depleted NAD+ in tumor cells and showed potent growth inhibitory activity with IC50 values in the subnanomolar- to nanomolar range in a target-dependent manner. A C4.4a-NAMPTi-ADC and a HER2-NAMPTi-ADC were tested In the C4.4a- and HER2-expressing MDA-MB-453 cell line derived subcutaneous breast cancer model xenografted on NOD/SCID mice. Both NAMPTi-ADCs showed highly potent anti-tumor Efficacy: The C4.4a-NAMPTi-ADC induced complete responses (in 3 of 8 mice) and stable diseases (in 5 of 8 mice) and the HER2-NAMPTi-ADC achieved complete tumor regression in all treated animals. In addition, in the THP-1 acute myeloid leukemia (AML) subcutaneous in vivo model, a B7H3-NAMPTi-ADC induced complete tumor responses in 7 of 8 treated animals. Taken together, we identified a new series of NAMPT inhibitors as a novel class of ADC payloads exhibiting strong in vivo efficacy in various preclinical xenograft models.

Citation Format: Anette Sommer, Stefanie Hammer, Sandra Berndt, Antje M. Wengner, Niels Boehnke, Markus Berger, Nils Griebenow, Andreas Steffen, Beatrix Stelte-Ludwig, Christoph Mahlert, Simone Greven, Lisa Dietz, Hannah Joerissen, Anja Giese, Maria Quanz, Zhengzheng Bao, Xiuli Wu, Hilmar Weinmann, Lars Linden, Bertolt Kreft, Dominik Mumberg. Anti-tumor activity of a novel structural class of NAMPT inhibitor-based ADCs in models of hematologic and solid tumor indications [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1807.

Abstract 2257: Targeted thorium-227 conjugates demonstrate synergistic activity in combination with PD-L1 inhibitors

Targeted thorium-227 conjugates (TTCs) represent a new class of targeted alpha therapy (TAT). TTCs consist of an antigen targeting moiety, which is covalently attached to a 3,2-HOPO chelator, enabling specific complexation and delivery of the alpha particle emitter thorium-227 to tumor cells. TTCs have demonstrated potent preclinical in vivo activity in monotherapy and in combination with DNA damage inhibitors. In the present work, the immunostimulatory effects of the mesothelin (MSLN) targeted thorium-227 conjugate (MSLN-TTC) was studied in immunocompetent mice, bearing human MSLN-transfected MC38 cells, in monotherapy and in combination with the PD-L1 inhibitor (PD-L1i) atezolizumab. Surface expression of DAMPs (calreticulin, HMGB1, HSP70 and HSP90), immunoinhibitory markers (PD-L1 and CTLA-4) and immunostimulatory markers (IFNAR, B7H2 and ICOS-L) was analyzed on murine, human MSLN-transfected MC38 colorectal cancer cells (MC38-hMSLN cells) after a 3-day exposure to MSLN-TTC. In vivo, C57/Bl6 mice were inoculated s.c. with MC38-hMSLN cells and treated with a single i.v. dose of non-radiolabeled MSLN-conjugate (0.14 mg/kg), isotype control-TTC (250 kBq/kg; 0.14 mg/kg), MSLN-TTC (250 kBq/kg; 0.14 mg/kg), PD-L1i (1.5 mg/kg; Q3D4; i.p.) or MSLN-TTC/PD-L1i combination. Tumors, lymph nodes, spleen and plasma were analyzed for MSLN and molecular markers. Tumor-free survivors were re-challenged with MC38-hMSLN or vector cells 125 d post-treatment. In a parallel arm of the experiment, CD8+ T cells were depleted using YTS169.4 antibody. MSLN-TTC treatment resulted in a specific dose-dependent increase of IFNAR, PD-L1 and HMGB1 in MC38-hMSLN cells in vitro. MSLN-TTC (T/C 0.38; Day 22) and PD-L1i (T/C 0.0.42; Day 22) monotherapies showed specific antitumor activity (T/C of radiolabeled isotype control was 0.76, Day 22) and their combination was synergistic (T/C 0.08; Day 22) with increased numbers of tumor free survivors. All three treatments increased HMGB1 levels in plasma. Induction of DSBs was observed in MSLN-TTC (+/- PD-L1i) treated tumors. Re-challenge of tumor-free survivors treated with MSLN-TTC, PD-L1i or MSLN-TTC/PD-L1i resulted in rejection of MC38-hMSLN, but not vector-cells. Infiltration of CD8+ T cells into tumors and their increase in tumor-draining lymph nodes were observed in MSLN-TTC, PD-L1i and MSLN-TTC/PD-L1i-treated groups but not in the vehicle group. Depletion of CD8+ T cells decreased the efficacy of PD-L1i and to a lower extent, MSLN-TTC and MSLN-TTC/PD-L1i. These results suggest that the efficacy of MSLN-TTC may involve activation of CD8+ T cells. These findings support the hypothesis that upon binding to antigen-positive cancer cells, TTC treatment induces DNA double strand breaks, leading to apoptosis and potentially immunogenic cell death, resulting in activation of the adaptive immune system.

Citation Format: Urs B. Hagemann, Pascale Lejeune, Lisa Bartnitzky, Kathleen Stadelmann, Veronique Cruciani, Roger M. Bjerke, Sandra Berndt, Claudia Kamfenkel, Manuela Brand, Manuela Steinbach, Stefan Stargard, Christoph A. Schatz, Jenny Karlsson, Hartwig Hennekes, Alan S. Cuthbertson, Dominik Mumberg. Targeted thorium-227 conjugates demonstrate synergistic activity in combination with PD-L1 inhibitors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2257.

Abstract 677: Effective depletion of M2 macrophages by CD206-NAMPT-ADCs

Introduction/ Purpose of study Targeting M2 macrophages as an immunosuppressive cell population within the tumor-microenvironment has become an important effort within preclinical research to achieve and enhance anti-tumor efficacy. In contrast to reprogramming approaches, we focused on effective and specific depletion of M2 macrophages (Mphs) by a new antibody-drug-conjugate (ADC) comprising a CD206-binding antibody conjugated to a nicotinamide phosphoribosyl transferase (NAMPT) toxophore which was proved to be very potent in cell killing.

Description of procedures Human (hu) and mouse (ms) cross-reactive CD206 antibodies were identified by phage display using recombinant hu/ms CD206-extracellular domains. Selected clones showing strong CD206 binding by ELISA were reformatted into huIgG1 format and cellular targeting confirmed by FACS binding and internalization using CD206-transfected HEK cells. Antibodies were conjugated to a NAMPT toxophore by Cys-conjugation using two different non-cleavable linkers. Murine peritoneal Mphs collected after thioglycolate stimulation were polarized to M1 (LPS + IFNγ) or M2 (IL4 + IL13 + PGE2) within 24h and characterized for cytokines and typical markers via FACS (CD206, CD163, CD80/MHCII) and qPCR (iNOS, TGFβ, ARG1). After 96h treatment with either CD206- or isotype-NAMPT-ADCs, viability of Mphs was determined. In vivo pharmacokinetics (PK) of unconjugated antibodies were analyzed in plasma of female BALB/c mice for up to 72h.

Summary of data Of the resulting 57 hu/ms cross-reactive CD206-binding antibodies, TPP-17829 and TPP-17836 were identified with single-digit nanomolar binding affinity and strong internalization in CD206-transfected cells as a prerequisite for an ADC approach. Conjugation of the antibodies to NAMPT toxophores yielded drug-antibody-ratios of 4-7 as determined by SEC-UV without significant aggregation. These two CD206-NAMPT-ADCs successfully depleted polarized M2-Mphs characterized by high CD206 expression, whereas isotype-NAMPT-ADC controls had no effect. While the unconjugated NAMPT toxophore was potent in depleting primary low-proliferating M1/M2 Mphs, by comparison, the anti-proliferative toxophore KSP (kinesin-spindle-protein inhibitor) was completely ineffective. PK analysis of TPP-17829 and TPP-17836, however, revealed a rapid plasma clearance within the first hours, most likely target-mediated via the liver, rendering them unacceptable for in vivo efficacy testing as NAMPT-ADCs.

Conclusions CD206-NAMPT-ADCs demonstrated proof of concept for specific depletion of M2-Mphs in vitro. However, specific in vivo depletion of M2 Mphs from tumors will be challenging with respect to fast plasma clearance observed for anti-CD206 antibodies.

Citation Format: Sandra Berndt, Katharina Filarsky, Patrick Smith, Niels Boehnke, Markus Berger, Fionnuala McAleese Eser, Hans-Georg Lerchen, Phillip Ellinger, Mathias Gehrmann, Jim Wu, Dominic Hildebrand, Bertolt Kreft, Uwe Gritzan. Effective depletion of M2 macrophages by CD206-NAMPT-ADCs [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 677.

Auto-antibodies to p53 and the Subsequent Development of Colorectal Cancer in a United States Prospective Cohort Consortium

Auto-antibodies to tumor suppressor p53 are found in a subset of colorectal cancer (CRC) patients. A prospective cohort study in the US (Cancer Prevention Study II) has recently reported a statistically significant 1.8-fold increased odds for the development of CRC based on pre-diagnostic sero-positivity for p53; the magnitude of this association decreased with longer time-span between blood sampling and diagnosis. In the present study, we sought to examine this association in a large US CRC cohort consortium to evaluate the potential utility of p53 auto-antibodies as an early CRC detection biomarker. Methods: Antibody responses to p53 were measured in pre-diagnostic blood samples of 3,702 incident CRC cases (median [range] follow-up: 7.3 years [0–40 years]) and an equal number of controls, matched by age, race, and sex, from 9 US prospective cohorts. The association of sero-positivity to p53 with CRC risk, overall and by time between blood draw and diagnosis, was determined by conditional logistic regression. Results: Overall, 5% of controls and 7% of cases were sero-positive to p53, resulting in a statistically significant 33% increased CRC risk (OR: 1.33; 95% CI: 1.09, 1.61). The association was strongest for CRC diagnoses within 2 years after blood draw (OR: 2.73; 95% CI: 1.67, 4.45), with 15% sero-positive cases compared to 6% sero-positive controls. The number of sero-positive cases decreased with longer follow-up time (2–&lt;5 years: 9%; 5–&lt;10 years: 6%; ≥10 years: 3%) down to a proportion similar to that in controls resulting in the absence of an association of p53 sero-positivity with CRC risk after more than 5 years between blood draw and CRC diagnosis. Conclusion: In this large consortium of prospective cohorts, we found that pre-diagnostic sero-positivity to the tumor suppressor p53 was statistically significantly associated with a 2.7-fold increased risk of a subsequent CRC diagnosis within 2 years after blood draw, replicating the findings of the one previous cohort study examining this association. The findings suggest that while p53 sero-positivity may not be a useful predictor of long-term CRC risk, p53 auto-antibodies might be considered as part of a marker panel for early detection of this cancer.

Abstract 4816: Anetumab ravtansine has monotherapy efficacy in mesothelin positive patient-derived NSCLC tumor models and in a syngeneic tumor model in immunocompetent mice

Chemotherapy and immune checkpoint inhibitors (ICIs) are approved for treatment of non-small-cell lung cancer (NSCLC). However, there still remains a high medical need in NSCLC, eg. in patients non-responsive to ICIs or progressed after treatment with ICIs. Mesothelin (MSLN) is expressed in ~60% of lung adenocarcinomas. Here, we describe the mesothelin targeting antibody drug conjugate anetumab ravtansine (ARav) with the maytansinoid payload (DM4) as a novel treatment option for NSCLC.

In the NSCLC cell line-derived xenograft model NCI-H322, ARav dosed at 2.5 mg/kg or 10 mg/kg, Q3Dx3, i.v., showed significant antitumor activity and was superior to cisplatin (dosed 3 mg/kg, Q3Dx12, ip). In addition, ARav monotherapy also showed antitumor activity in MSLN-positive NSCLC patient-derived xenograft (PDX) tumor models ST1243 and ST1684 at 15 mg/kg, Q2W.

Maytansinoids and maytansinoid-based ADCs have been described to induce immunogenic cell death and immune response in vitro and in vivo, respectively. To explore the effects of ARav alone or in combination with anti PD-L1 Ab on tumor growth and the immune system, the MC38 C57BL/6 mouse colon cancer cell line was stably transfected with human mesothelin (MC38-hMSLN).

MC38-hMSLN cells were transplanted s.c. in immunocompetent C57BL/6 mice to evaluate the anti-tumor activity of ARav. MC38-hMSLN had a high hMSLN expression level as shown by IHC. A dose of 10 mg/kg of ARav (Q3Dx3, i.v.) was highly efficacious with 11/12 animals showing complete regression of the tumor. Tumor free survivors (TFS) re-challenged 80 days after treatment all rejected MC38-hMSLN (11/11 animals), indicating the development of an immune memory response. The specificity of the immune response was further confirmed in an independently conducted experiment, where previously ARav treated MC38-hMSLN TFS mice were re-challenged with B16-F10 melanoma cells, which grew.

Next, a lower dose of ARav (3 mg/kg, Q3Dx3, i.v.) was combined with an anti PD-L1 antibody in the MC38-hMSLN tumor bearing mice. The combination led to increased frequency of TFS compared to each monotherapy (12/12 TFS in the combination versus 7/12 for the anti PD-L1 and 2/12 for ARav). Further studies are currently ongoing to optimize the combination dosing and schedule as well as to characterize the immune cells involved in the response.

In summary, the data supports the development of ARav in NSCLC and further exploration of ARav in combination with immune checkpoint inhibitors in MSLN-positive cancer indications.

Anetumab ravtansine clinical activity is currently assessed at phase I studies in ovarian cancer in combination with pegylated liposomal doxorubicin (Phase 1b, NCT02751918), in multiple indications including NSCLC (Phase Ib, NCT03102320), and in combination with the anti PD-L1 antibody atezolizumab in NSCLC (Phase I /II, NCT03455556).

Citation Format: Anette Sommer, Pascale Lejeune, Sabine Hoff, Annette O. Walter, Sandra Berndt, Lars Roese, Andreas Schlicker, Michael J. Wick, Cem Elbi, Dominik Mumberg, Christoph Schatz. Anetumab ravtansine has monotherapy efficacy in mesothelin positive patient-derived NSCLC tumor models and in a syngeneic tumor model in immunocompetent mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4816.

Abstract 228: KSPi-ADCs: ADCs with novel kinesin spindle protein inhibitor payloads and a tailor-made linker chemistry

Inhibitors of kinesin spindle protein (KSP/Eg5) have raised great interest because of their high antitumor potency which, however, could not be transferred into highly efficient clinical regimens due to dose limiting side effects such as neutropenia. We have developed a new, highly potent pyrrole subclass of KSPis as a novel payload class in ADCs. To increase the therapeutic window, a tailor-made effector chemistry has been designed. The tumor associated protease legumain (LGMN) is utilized for ADC cleavage to provide active metabolites with high and long-lasting exposure in tumors, thus matching the KSPi mode of action. LGMN is a lysosomal asparaginyl endopeptidase overexpressed in solid tumors which is associated with invasion, metastasis and poor survival. In our studies, we show an efficient LGMN mediated linker cleavage and payload release from different ADCs. In addition, the unique LGMN substrate sequence allows for high cleavage specificity and discrimination versus other proteases such as elastase, which has been associated with an undesired extracellular cleavage of e.g. vc-MMAE ADCs resulting in neutropenia. Variations of the linker chemistry were performed to retain high potency of the KSPi-ADCs against tumor cells while decreasing the activation of KSPi-ADCs in cells of healthy organs such as the liver. From this approach, highly potent KSPi-ADCs with improved tumor/organ ratios of active metabolites were obtained. In conclusion, ADC metabolism under legumain control is a versatile strategy to provide KSPi-ADCs with high potency and an improved safety profile.

Citation Format: Hans-Georg Lerchen, Beatrix Stelte-Ludwig, Anette Sommer, Sandra Berndt, Anne-Sophie Rebstock, Sarah Johannes, Leo Marx, Christoph Mahlert, Simone Greven, Lisa Dietz, Hannah Joerissen, Hilmar Weinmann. KSPi-ADCs: ADCs with novel kinesin spindle protein inhibitor payloads and a tailor-made linker chemistry [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 228.

Abstract 272: Synergistic activity of the ATR inhibitor BAY1895344 in combination with immune checkpoint inhibitors in preclinical tumor models

The DNA damage response (DDR) consists of complex signaling pathways that secure the integrity of the genome in eukaryotic cells. Numerous lines of evidence suggest that enhanced DNA damage caused by intrinsically or acquired defects in DDR, increases tumor immunogenicity, potentially impacting anti-tumor immune responses and sensitivity to immune checkpoint inhibition. The ataxia telangiectasia and Rad3-related (ATR) kinase plays a central role in DDR by activating essential signaling pathways of DNA damage repair and is the key mediator of the replication stress response being indispensable for cellular proliferation and viability. Inhibition of ATR has been shown to lead to impaired cell cycle progression, increased DNA damage and replication stress ultimately resulting in rapid cellular lethality. The potential of combining inhibition of ATR with immune checkpoint blockade was studied in preclinical tumor models. We assessed efficacy of the novel ATR inhibitor (ATRi) BAY 1895344 in monotherapy and in combination with anti-PD-1 (Programmed Death 1) or anti-PD-L1 (Programmed Death 1 Ligand 1) antibody in syngeneic tumor models in immunocompetent mice. Interestingly, depletion of CD8+ T cells strongly reduced single agent activity of BAY 1895344 in the C57BL/6 mouse colorectal cancer (CRC) model MC38. Along this line, synergistic anti-tumor activity of BAY 1895344 and anti-PD-1/ PD-L1 could be demonstrated in MC38 tumors as well as in the BALB/c CRC model CT26 (both anti-PD-1/ PD-L1 sensitive), and the lymphoma model A20 (anti-PD-1/ PD-L1 insensitive). Remarkably, the synergistic activity was only achieved by sequential dosing of combination partners in the schedule: 1) anti-PD-1/PD-L1 Q2W (days 1 and 4 each week) followed by 2) BAY 1895344 BID 3 days on/ 4 days off (days 5, 6, 7 each week). Concomitant application or sequential dosing in the reverse order did not result in synergy or was even antagonizing single agent-mediated anti-tumor effects. Potential mechanisms underlying the interplay of ATRi and immune system activation will be discussed. Overall, our data suggest that the combination of immune checkpoint inhibitors and ATRi BAY 1895344 may enhance the anti-tumor efficacy of each single agent and potentially re-sensitize tumors to immune oncology treatments. BAY 1895344 is currently under clinical investigation in patients with advanced solid tumors and lymphomas as single agent (NCT03188965). Clinical exploration of a combination with anti-PD-1 is warranted.

Citation Format: Antje Margret Wengner, Dennis Kirchhoff, Lars Roese, Sandra Berndt, Gerhard Siemeister, Bertolt Kreft, Dominik Mumberg. Synergistic activity of the ATR inhibitor BAY1895344 in combination with immune checkpoint inhibitors in preclinical tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 272.

Crystal structure of the SH3 domain of human Lyn non-receptor tyrosine kinase

Lyn kinase (Lck/Yes related novel protein tyrosine kinase) belongs to the family of Src-related non-receptor tyrosine kinases. Consistent with physiological roles in cell growth and proliferation, aberrant function of Lyn is associated with various forms of cancer, including leukemia, breast cancer and melanoma. Here, we determine a 1.3 Å resolution crystal structure of the polyproline-binding SH3 regulatory domain of human Lyn kinase, which adopts a five-stranded β-barrel fold. Mapping of cancer-associated point mutations onto this structure reveals that these amino acid substitutions are distributed throughout the SH3 domain and may affect Lyn kinase function distinctly.

The Structure of the Bifunctional Everninomicin Biosynthetic Enzyme EvdMO1 Suggests Independent Activity of the Fused Methyltransferase-Oxidase Domains

Members of the orthosomycin family of natural products are decorated polysaccharides with potent antibiotic activity and complex biosynthetic pathways. The defining feature of the orthosomycins is an orthoester linkage between carbohydrate moieties that is necessary for antibiotic activity and is likely formed by a family of conserved oxygenases. Everninomicins are octasaccharide orthosomycins produced by Micromonospora carbonacea that have two orthoester linkages and a methylenedioxy bridge, three features whose formation logically requires oxidative chemistry. Correspondingly, the evd gene cluster encoding everninomicin D encodes two monofunctional nonheme iron, α-ketoglutarate-dependent oxygenases and one bifunctional enzyme with an N-terminal methyltransferase domain and a C-terminal oxygenase domain. To investigate whether the activities of these domains are linked in the bifunctional enzyme EvdMO1, we determined the structure of the N-terminal methyltransferase domain to 1.1 Å and that of the full-length protein to 3.35 Å resolution. Both domains of EvdMO1 adopt the canonical folds of their respective superfamilies and are connected by a short linker. Each domain's active site is oriented such that it faces away from the other domain, and there is no evidence of a channel connecting the two. Our results support EvdMO1 working as a bifunctional enzyme with independent catalytic activities.

Structural basis of arrestin-3 activation and signaling

A unique aspect of arrestin-3 is its ability to support both receptor-dependent and receptor-independent signaling. Here, we show that inositol hexakisphosphate (IP₆) is a non-receptor activator of arrestin-3 and report the structure of IP₆-activated arrestin-3 at 2.4-Å resolution. IP₆-activated arrestin-3 exhibits an inter-domain twist and a displaced C-tail, hallmarks of active arrestin. IP₆ binds to the arrestin phosphate sensor, and is stabilized by trimerization. Analysis of the trimerization surface, which is also the receptor-binding surface, suggests a feature called the finger loop as a key region of the activation sensor. We show that finger loop helicity and flexibility may underlie coupling to hundreds of diverse receptors and also promote arrestin-3 activation by IP₆. Importantly, we show that effector-binding sites on arrestins have distinct conformations in the basal and activated states, acting as switch regions. These switch regions may work with the inter-domain twist to initiate and direct arrestin-mediated signaling.

While arrestins are mainly associated with GPCR signaling, arrestin-3 can signal independently of receptor interaction. Here the authors present the structure of arrestin-3 bound to inositol hexakisphosphate (IP₆) and propose a model for arrestin-3 activation.

Antitumor effects of regorafenib and sorafenib in preclinical models of hepatocellular carcinoma

The purpose of this study was to investigate the antitumor activity of regorafenib and sorafenib in preclinical models of HCC and to assess their mechanism of action by associated changes in protein expression in a HCC-PDX mouse model. Both drugs were administered orally once daily at 10 mg/kg (regorafenib) or 30 mg/kg (sorafenib), which recapitulate the human exposure at the maximally tolerated dose in mice.

In a H129 hepatoma model, survival times differed significantly between regorafenib versus vehicle (p=0.0269; median survival times 36 vs 27 days), but not between sorafenib versus vehicle (p=0.1961; 33 vs 28 days). Effects on tumor growth were assessed in 10 patient-derived HCC xenograft (HCC-PDX) models. Significant tumor growth inhibition was observed in 8/10 models with regorafenib and 7/10 with sorafenib; in four models, superior response was observed with regorafenib versus sorafenib which was deemed not to be due to lower sorafenib exposure. Bead-based multiplex western blot analysis was performed with total protein lysates from drug- and vehicle-treated HCC-PDX xenografts. Protein expression was substantially different in regorafenib- and sorafenib-treated samples compared with vehicle. The pattern of upregulated proteins was similar with both drugs and indicates an activated RAF/MEK/ERK pathway, but more proteins were downregulated with sorafenib versus regorafenib. Overall, both regorafenib and sorafenib were effective in mouse models of HCC, although several cases showed better regorafenib activity which may explain the observed efficacy of regorafenib in sorafenib-refractory patients.

Comparison of [(11)C]Choline ([(11)C]CHO) and [(18)F]Bombesin (BAY 86-4367) as Imaging Probes for Prostate Cancer in a PC-3 Prostate Cancer Xenograft Model

PURPOSE

Carbon-11- and fluorine-18-labeled choline derivatives are commonly used in prostate cancer imaging in the clinical setting for staging and re-staging of prostate cancer. Due to a limited detection rate of established positron emission tomography (PET) tracers, there is a clinical need for innovative tumor-specific PET compounds addressing new imaging targets. The aim of this study was to compare the properties of [(18)F]Bombesin (BAY 86-4367) as an innovative biomarker for prostate cancer imaging targeting the gastrin-releasing peptide receptor and [(11)C]Choline ([(11)C]CHO) in a human prostate tumor mouse xenograft model by small animal PET/X-ray computed tomography (CT).

PROCEDURES

We carried out a dual-tracer small animal PET/CT study comparing [(18)F]Bombesin and [(11)C]CHO. The androgen-independent human prostate tumor cell line PC-3 was implanted subcutaneously in the flanks of nu/nu NMRI mice (n = 10) (PET/CT measurements of two [(11)C]Choline mice could not be analyzed due to technical reasons). [(18)F]Bombesin and [(11)C]CHO PET/CT imaging was performed about 3-4 weeks after the implantation of PC-3 cells on two separate days. After the intravenous tail vein injection of 14 MBq [(18)F]Bombesin and 37 MBq [(11)C]CHO, respectively, a dynamic study over 60 min was acquired in list mode using an Inveon animal PET/CT scanner (Siemens Medical Solutions). The sequence of [(18)F]Bombesin and [(11)C]CHO was randomized. Image analysis was performed using summed images as well as dynamic data. To calculate static and dynamic tumor-to-muscle (T/M), tumor-to-blood (T/B), liver-to-blood (L/B), and kidney-to-blood (K/B) ratios, 4 × 4 × 4 mm(3) volumes of interest (VOIs) of tumor, muscle (thigh), liver, kidney, and blood derived from transversal slices were used.

RESULTS

The mean T/M ratio of [(18)F]Bombesin and [(11)C]CHO was 6.54 ± 2.49 and 1.35 ± 0.30, respectively. The mean T/B ratio was 1.83 ± 0.79 for [(18)F]Bombesin and 0.55 ± 0.10 for [(11)C]CHO. The T/M ratio as well as the T/B ratio for [(18)F]Bombesin were significantly higher compared to those for [(11)C]CHO (p < 0.001, respectively). Kidney and liver uptake was statistically significantly lower for [(18)F]Bombesin (K/B 3.41 ± 0.81, L/B 1.99 ± 0.38) compared to [(11)C]CHO [K/B 7.91 ± 1.85 (p < 0.001), L/B 6.27 ± 1.99 (p < 0.001)]. The magnitudes of the time course of T/M and T/B ratios (T/M and T/Bdyn ratios) were statistically significantly different (showing a higher uptake of [(18)F]Bombesin compared to [(11)C]CHO); additionally, also the change of the T/M and T/B ratios over time was significantly different between both tracers in the dynamic analysis (p < 0.001, respectively). Furthermore, there was a statistically significantly different change of the K/B and L/B ratios over time between the two tracers in the dynamic analysis (p = 0.026 and p < 0.001, respectively).

CONCLUSIONS

[(18)F]Bombesin (BAY 86-4367) visually and semi-quantitatively outperforms [(11)C]CHO in the PC-3 prostate cancer xenograft model. [(18)F]Bombesin tumor uptake was significantly higher compared to [(11)C]CHO. [(18)F]Bombesin showed better imaging properties compared to the clinically utilized [(11)C]CHO due to a higher tumor uptake as well as a lower liver and kidney uptake.

Abstract 3234: Development of potent and selective antibody-drug conjugates with pyrrole-based KSP inhibitors as novel payload class

The number of cytotoxic payload classes with different modes-of-action which have been successfully employed in antibody-drug conjugates (ADC) is still rather limited. So far, only ADCs with microtubule inhibitors, DNA binding payloads or topoisomerase I inhibitors have been advanced into clinical testing. To this end, the identification of ADC payload classes with a novel mode of action will increase therapeutic options and potentially help to overcome resistance. Inhibitors of kinesin spindle protein (KSP/Eg5) have generated interest due to their high antitumor potency. However, transferring the preclinical potency of small molecule KSP inhibitors (KSPis) into highly efficient clinical regimens with a sufficient therapeutic window has remained challenging. We have investigated a new pyrrole subclass of KSPis which showed subnanomolar potency against a large panel of tumor cell lines for their utility as a novel payload class in ADCs. Towards this goal different attachment sites for linkers have been explored in the KSPi molecule which were found compatible with cleavable and/or non-cleavable linkers. Subnanomolar potency and selectivity of ADCs with antibodies targeting either HER2, EGFR or TWEAKR could be demonstrated in vitro. For selected ADCs, the intracellular trafficking and metabolite formation was investigated and KSP inhibition was confirmed as the ADC mode of action. Depending on the linker composition differential profiles of the ADC metabolites with regard to efflux, cellular permeation, and bystander effect have been achieved. Moreover, specific accumulation in the tumor versus other tissues was demonstrated in biodistribution studies in vivo. In conclusion, KSP inhibitors have been established as a versatile new payload class for the generation of highly potent and selective ADCs.

Citation Format: Hans-Georg Lerchen, Sven Wittrock, Nils Griebenow, Mario Lobell, Anne-Sophie Rebstock, Yolanda Cancho-Grande, Beatrix Stelte-Ludwig, Christoph Mahlert, Simone Greven, Anette Sommer, Sandra Berndt, Carsten Terjung, Heiner Apeler, Bertolt Kreft, Rolf Jautelat. Development of potent and selective antibody-drug conjugates with pyrrole-based KSP inhibitors as novel payload class [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3234. doi:10.1158/1538-7445.AM2017-3234

Abstract 46: Preclinical activity of novel antibody-drug conjugates with pyrrole-based kinesin spindle protein inhibitors targeting different tumor antigens

Antibody-drug conjugates (ADCs) are promising agents that are developed for targeted delivery of cytotoxic payloads to tumor cells. ADCs share a common design of antibody, linker, and cytotoxic payload. Despite significant efforts, the number of available payload classes with a differentiated mode-of-action that can successfully be employed to generate antibody-drug conjugates (ADCs) is still rather limited. So far, only ADCs with microtubule depolymerizing or DNA binding payloads have been approved. The identification of ADC payload classes with a novel mode-of-action will increase therapeutic options and potentially help to overcome resistance. Inhibitors of the kinesin spindle protein (KSP/Eg5/KIF11) have generated interest due to their high anti-tumor activity. However, the transfer of the potency of small molecule KSP inhibitors (KSPis) to highly efficient clinical regimens with a sufficient therapeutic window remains challenging. Through the conjugation of a novel pyrrole subclass of KSPis to antibodies targeting different cancer antigens, we generated a panel of ADCs and characterized them both in vitro and in vivo. ADCs targeting either EGFR or TWEAKR/Fn14 showed strong and specific internalization and displayed specific and potent anti-proliferative efficacy in vitro. In cytotoxicity assays, these ADCs exhibited sub-nanomolar potency in antigen-positive cancer cell lines (EGFR/TWEAKR-pos. NCI-H292; TWEAKR-pos. BxPC3, LoVo) and more than 100-fold selectivity versus non-targeted control-ADC containing the same linker and the same payload. Furthermore, selective anti-tumor efficacy of EGFR- and TWEAKR-KSPi-ADCs was demonstrated in vivo using both cancer cell line-derived models of NSCLC (NCI-H292), urothelial cell carcinoma (UCC) (KU-19-19), and renal cell carcinoma (A498), as well as in the TWEAKR-positive patient-derived xenograft UCC model BFX469. At doses of 5-10 mg/kg qw or bw potent anti-tumor efficacy with treated-to-control ratios (T/C) between 0.16 to 0.28 as well as complete regressions were observed. In summary, KSP inhibitors have been established as a promising new payload class allowing the generation of highly potent and selective ADCs for the treatment of solid tumors.

Citation Format: Anette Sommer, Sandra Berndt, Hans-Georg Lerchen, Beatrix Stelte-Ludwig, Sven Wittrock, Anne-Sophie Rebstock, Lisa Dietz, Christoph Mahlert, Simone Greven, Nils Griebenow, Yolanda Cancho-Grande, Rolf Jautelat, Heiner Apeler, Bertolt Kreft. Preclinical activity of novel antibody-drug conjugates with pyrrole-based kinesin spindle protein inhibitors targeting different tumor antigens [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 46. doi:10.1158/1538-7445.AM2017-46

Teacher Perceptions and the Consequential Validity of an Alternate Assessment for Students With Significant Cognitive Disabilities

The purpose of this investigation was to understand the variables that influence teachers' perceptions regarding one state's alternate assessment process and results. Elementary and secondary special education teachers (N = 113) from across Wisconsin participated, submitting case materials for one of their students. These materials included the a copy of the students' WisconsinAlternative Assessment (WAA) rating scale and current Individualized Education Program (IEP); a brief survey regarding their perceptions of the WAA; and a curricular access questionnaire that documented which WAA items were part of the student's curriculum during the current or previous school year. A stepwise multiple regression analysis was conducted to determine the relationship between predictor variables and teachers' perceptions as reported on the teacher survey. The results indicated student grade level accounted for the small amount of the variation in teacher's positive perceptions of the WAA. These results are discussed in the context of consequential evidence for the validity of the WAA.

Abstract 2089: Therapeutic index prediction of the agonistic aglycosylated TWEAK receptor binding antibody BAY-356

BAY-356 is a novel aglycosylated anti-TWEAK receptor antibody with potent agonistic activity evaluated for cancer therapy. In order to predict an efficacious therapeutic dose of BAY-356 in man, we sought to determine a therapeutic index where the exposure related to therapeutic efficacy was compared with the exposure obtained following doses tested in toxicology studies.

BAY-356 (1 mg/kg) was administered intravenously to healthy Cynomolgus monkeys and plasma concentrations measured in order to determine pharmacokinetic (PK) parameters. Using allometric scaling, the PK in humans was predicted. Efficacy data of BAY-356 in WiDr, HN10321, A253 and SCaBER xenograft models representing colorectal, head and neck squamous cell carcinoma and bladder cancer, were used to derive exposure-response models for each tumor model where the plasma exposure of BAY-356 is assumed to have an effect on the tumor size in a tumor growth model. NONMEM 7.3 was used in the estimations.

The tolerability of BAY-356 was tested in monkeys at doses of 10, 20 and 40 mg/kg by weekly intravenous injections over 4 weeks. Treatment resulted in slight to moderate toxicity in liver, kidneys and pancreas and 10 mg/kg was set to be an exposure dose well tolerated and not to be exceeded by therapeutic exposure. A dosing strategy in humans predicted to result in the same exposure as 10 mg/kg weekly in monkey is 18 mg/kg every third weeks (Q3W).

Using the estimated exposure-response in xenograft models, human tumor doubling times of 8 weeks (A253 and HN10321), 24 weeks (WiDr) and 12 and 24 weeks (SCaBER) in combination with human predicted PK parameters, tumor reduction over time in humans was predicted based on a human dosing strategy of 18 mg/kg BAY-356 Q3W. For the A253 tumor model, stable disease in humans was predicted while the results from HN10321 and SCaBER models predicted a 13-60% decrease in tumor size in humans following 12 weeks treatment. For WiDr, this dosing strategy was predicted to not be efficacious in humans.

The results based on modelling of xenograft data indicate that 18 mg/kg BAY-356 dosed Q3W is predicted to be efficacious in humans for certain tumor cells.

Citation Format: Anders Viberg, Eva Hanze, Lisa Dietz, Ruprecht Zierz, Sandra Berndt, Sabine Wittemer-Rump. Therapeutic index prediction of the agonistic aglycosylated TWEAK receptor binding antibody BAY-356. [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 2089.

Human genome meeting 2016 : Houston, TX, USA. 28 February - 2 March 2016

O1 The metabolomics approach to autism: identification of biomarkers for early detection of autism spectrum disorder A. K. Srivastava, Y. Wang, R. Huang, C. Skinner, T. Thompson, L. Pollard, T. Wood, F. Luo, R. Stevenson O2 Phenome-wide association study for smoking- and drinking-associated genes in 26,394 American women with African, Asian, European, and Hispanic descents R. Polimanti, J. Gelernter O3 Effects of prenatal environment, genotype and DNA methylation on birth weight and subsequent postnatal outcomes: findings from GUSTO, an Asian birth cohort X. Lin, I. Y. Lim, Y. Wu, A. L. Teh, L. Chen, I. M. Aris, S. E. Soh, M. T. Tint, J. L. MacIsaac, F. Yap, K. Kwek, S. M. Saw, M. S. Kobor, M. J. Meaney, K. M. Godfrey, Y. S. Chong, J. D. Holbrook, Y. S. Lee, P. D. Gluckman, N. Karnani, GUSTO study group O4 High-throughput identification of specific qt interval modulating enhancers at the SCN5A locus A. Kapoor, D. Lee, A. Chakravarti O5 Identification of extracellular matrix components inducing cancer cell migration in the supernatant of cultivated mesenchymal stem cells C. Maercker, F. Graf, M. Boutros O6 Single cell allele specific expression (ASE) IN T21 and common trisomies: a novel approach to understand DOWN syndrome and other aneuploidies G. Stamoulis, F. Santoni, P. Makrythanasis, A. Letourneau, M. Guipponi, N. Panousis, M. Garieri, P. Ribaux, E. Falconnet, C. Borel, S. E. Antonarakis O7 Role of microRNA in LCL to IPSC reprogramming S. Kumar, J. Curran, J. Blangero O8 Multiple enhancer variants disrupt gene regulatory network in Hirschsprung disease S. Chatterjee, A. Kapoor, J. Akiyama, D. Auer, C. Berrios, L. Pennacchio, A. Chakravarti O9 Metabolomic profiling for the diagnosis of neurometabolic disorders T. R. Donti, G. Cappuccio, M. Miller, P. Atwal, A. Kennedy, A. Cardon, C. Bacino, L. Emrick, J. Hertecant, F. Baumer, B. Porter, M. Bainbridge, P. Bonnen, B. Graham, R. Sutton, Q. Sun, S. Elsea O10 A novel causal methylation network approach to Alzheimer’s disease Z. Hu, P. Wang, Y. Zhu, J. Zhao, M. Xiong, David A Bennett O11 A microRNA signature identifies subtypes of triple-negative breast cancer and reveals MIR-342-3P as regulator of a lactate metabolic pathway A. Hidalgo-Miranda, S. Romero-Cordoba, S. Rodriguez-Cuevas, R. Rebollar-Vega, E. Tagliabue, M. Iorio, E. D’Ippolito, S. Baroni O12 Transcriptome analysis identifies genes, enhancer RNAs and repetitive elements that are recurrently deregulated across multiple cancer types B. Kaczkowski, Y. Tanaka, H. Kawaji, A. Sandelin, R. Andersson, M. Itoh, T. Lassmann, the FANTOM5 consortium, Y. Hayashizaki, P. Carninci, A. R. R. Forrest O13 Elevated mutation and widespread loss of constraint at regulatory and architectural binding sites across 11 tumour types C. A. Semple O14 Exome sequencing provides evidence of pathogenicity for genes implicated in colorectal cancer E. A. Rosenthal, B. Shirts, L. Amendola, C. Gallego, M. Horike-Pyne, A. Burt, P. Robertson, P. Beyers, C. Nefcy, D. Veenstra, F. Hisama, R. Bennett, M. Dorschner, D. Nickerson, J. Smith, K. Patterson, D. Crosslin, R. Nassir, N. Zubair, T. Harrison, U. Peters, G. Jarvik, NHLBI GO Exome Sequencing Project O15 The tandem duplicator phenotype as a distinct genomic configuration in cancer F. Menghi, K. Inaki, X. Woo, P. Kumar, K. Grzeda, A. Malhotra, H. Kim, D. Ucar, P. Shreckengast, K. Karuturi, J. Keck, J. Chuang, E. T. Liu O16 Modeling genetic interactions associated with molecular subtypes of breast cancer B. Ji, A. Tyler, G. Ananda, G. Carter O17 Recurrent somatic mutation in the MYC associated factor X in brain tumors H. Nikbakht, M. Montagne, M. Zeinieh, A. Harutyunyan, M. Mcconechy, N. Jabado, P. Lavigne, J. Majewski O18 Predictive biomarkers to metastatic pancreatic cancer treatment J. B. Goldstein, M. Overman, G. Varadhachary, R. Shroff, R. Wolff, M. Javle, A. Futreal, D. Fogelman O19 DDIT4 gene expression as a prognostic marker in several malignant tumors L. Bravo, W. Fajardo, H. Gomez, C. Castaneda, C. Rolfo, J. A. Pinto O20 Spatial organization of the genome and genomic alterations in human cancers K. C. Akdemir, L. Chin, A. Futreal, ICGC PCAWG Structural Alterations Group O21 Landscape of targeted therapies in solid tumors S. Patterson, C. Statz, S. Mockus O22 Genomic analysis reveals novel drivers and progression pathways in skin basal cell carcinoma S. N. Nikolaev, X. I. Bonilla, L. Parmentier, B. King, F. Bezrukov, G. Kaya, V. Zoete, V. Seplyarskiy, H. Sharpe, T. McKee, A. Letourneau, P. Ribaux, K. Popadin, N. Basset-Seguin, R. Ben Chaabene, F. Santoni, M. Andrianova, M. Guipponi, M. Garieri, C. Verdan, K. Grosdemange, O. Sumara, M. Eilers, I. Aifantis, O. Michielin, F. de Sauvage, S. Antonarakis O23 Identification of differential biomarkers of hepatocellular carcinoma and cholangiocarcinoma via transcriptome microarray meta-analysis S. Likhitrattanapisal O24 Clinical validity and actionability of multigene tests for hereditary cancers in a large multi-center study S. Lincoln, A. Kurian, A. Desmond, S. Yang, Y. Kobayashi, J. Ford, L. Ellisen O25 Correlation with tumor ploidy status is essential for correct determination of genome-wide copy number changes by SNP array T. L. Peters, K. R. Alvarez, E. F. Hollingsworth, D. H. Lopez-Terrada O26 Nanochannel based next-generation mapping for interrogation of clinically relevant structural variation A. Hastie, Z. Dzakula, A. W. Pang, E. T. Lam, T. Anantharaman, M. Saghbini, H. Cao, BioNano Genomics O27 Mutation spectrum in a pulmonary arterial hypertension (PAH) cohort and identification of associated truncating mutations in TBX4 C. Gonzaga-Jauregui, L. Ma, A. King, E. Berman Rosenzweig, U. Krishnan, J. G. Reid, J. D. Overton, F. Dewey, W. K. Chung O28 NORTH CAROLINA macular dystrophy (MCDR1): mutations found affecting PRDM13 K. Small, A. DeLuca, F. Cremers, R. A. Lewis, V. Puech, B. Bakall, R. Silva-Garcia, K. Rohrschneider, M. Leys, F. S. Shaya, E. Stone O29 PhenoDB and genematcher, solving unsolved whole exome sequencing data N. L. Sobreira, F. Schiettecatte, H. Ling, E. Pugh, D. Witmer, K. Hetrick, P. Zhang, K. Doheny, D. Valle, A. Hamosh O30 Baylor-Johns Hopkins Center for Mendelian genomics: a four year review S. N. Jhangiani, Z. Coban Akdemir, M. N. Bainbridge, W. Charng, W. Wiszniewski, T. Gambin, E. Karaca, Y. Bayram, M. K. Eldomery, J. Posey, H. Doddapaneni, J. Hu, V. R. Sutton, D. M. Muzny, E. A. Boerwinkle, D. Valle, J. R. Lupski, R. A. Gibbs O31 Using read overlap assembly to accurately identify structural genetic differences in an ashkenazi jewish trio S. Shekar, W. Salerno, A. English, A. Mangubat, J. Bruestle O32 Legal interoperability: a sine qua non for international data sharing A. Thorogood, B. M. Knoppers, Global Alliance for Genomics and Health - Regulatory and Ethics Working Group O33 High throughput screening platform of competent sineups: that can enhance translation activities of therapeutic target H. Takahashi, K. R. Nitta, A. Kozhuharova, A. M. Suzuki, H. Sharma, D. Cotella, C. Santoro, S. Zucchelli, S. Gustincich, P. Carninci O34 The undiagnosed diseases network international (UDNI): clinical and laboratory research to meet patient needs J. J. Mulvihill, G. Baynam, W. Gahl, S. C. Groft, K. Kosaki, P. Lasko, B. Melegh, D. Taruscio O36 Performance of computational algorithms in pathogenicity predictions for activating variants in oncogenes versus loss of function mutations in tumor suppressor genes R. Ghosh, S. Plon O37 Identification and electronic health record incorporation of clinically actionable pharmacogenomic variants using prospective targeted sequencing S. Scherer, X. Qin, R. Sanghvi, K. Walker, T. Chiang, D. Muzny, L. Wang, J. Black, E. Boerwinkle, R. Weinshilboum, R. Gibbs O38 Melanoma reprogramming state correlates with response to CTLA-4 blockade in metastatic melanoma T. Karpinets, T. Calderone, K. Wani, X. Yu, C. Creasy, C. Haymaker, M. Forget, V. Nanda, J. Roszik, J. Wargo, L. Haydu, X. Song, A. Lazar, J. Gershenwald, M. Davies, C. Bernatchez, J. Zhang, A. Futreal, S. Woodman O39 Data-driven refinement of complex disease classification from integration of heterogeneous functional genomics data in GeneWeaver E. J. Chesler, T. Reynolds, J. A. Bubier, C. Phillips, M. A. Langston, E. J. Baker O40 A general statistic framework for genome-based disease risk prediction M. Xiong, L. Ma, N. Lin, C. Amos O41 Integrative large-scale causal network analysis of imaging and genomic data and its application in schizophrenia studies N. Lin, P. Wang, Y. Zhu, J. Zhao, V. Calhoun, M. Xiong O42 Big data and NGS data analysis: the cloud to the rescue O. Dobretsberger, M. Egger, F. Leimgruber O43 Cpipe: a convergent clinical exome pipeline specialised for targeted sequencing S. Sadedin, A. Oshlack, Melbourne Genomics Health Alliance O44 A Bayesian classification of biomedical images using feature extraction from deep neural networks implemented on lung cancer data V. A. A. Antonio, N. Ono, Clark Kendrick C. Go O45 MAV-SEQ: an interactive platform for the Management, Analysis, and Visualization of sequence data Z. Ahmed, M. Bolisetty, S. Zeeshan, E. Anguiano, D. Ucar O47 Allele specific enhancer in EPAS1 intronic regions may contribute to high altitude adaptation of Tibetans C. Zeng, J. Shao O48 Nanochannel based next-generation mapping for structural variation detection and comparison in trios and populations H. Cao, A. Hastie, A. W. Pang, E. T. Lam, T. Liang, K. Pham, M. Saghbini, Z. Dzakula O49 Archaic introgression in indigenous populations of Malaysia revealed by whole genome sequencing Y. Chee-Wei, L. Dongsheng, W. Lai-Ping, D. Lian, R. O. Twee Hee, Y. Yunus, F. Aghakhanian, S. S. Mokhtar, C. V. Lok-Yung, J. Bhak, M. Phipps, X. Shuhua, T. Yik-Ying, V. Kumar, H. Boon-Peng O50 Breast and ovarian cancer prevention: is it time for population-based mutation screening of high risk genes? I. Campbell, M.-A. Young, P. James, Lifepool O53 Comprehensive coverage from low DNA input using novel NGS library preparation methods for WGS and WGBS C. Schumacher, S. Sandhu, T. Harkins, V. Makarov O54 Methods for large scale construction of robust PCR-free libraries for sequencing on Illumina HiSeqX platform H. DoddapaneniR. Glenn, Z. Momin, B. Dilrukshi, H. Chao, Q. Meng, B. Gudenkauf, R. Kshitij, J. Jayaseelan, C. Nessner, S. Lee, K. Blankenberg, L. Lewis, J. Hu, Y. Han, H. Dinh, S. Jireh, K. Walker, E. Boerwinkle, D. Muzny, R. Gibbs O55 Rapid capture methods for clinical sequencing J. Hu, K. Walker, C. Buhay, X. Liu, Q. Wang, R. Sanghvi, H. Doddapaneni, Y. Ding, N. Veeraraghavan, Y. Yang, E. Boerwinkle, A. L. Beaudet, C. M. Eng, D. M. Muzny, R. A. Gibbs O56 A diploid personal human genome model for better genomes from diverse sequence data K. C. C. Worley, Y. Liu, D. S. T. Hughes, S. C. Murali, R. A. Harris, A. C. English, X. Qin, O. A. Hampton, P. Larsen, C. Beck, Y. Han, M. Wang, H. Doddapaneni, C. L. Kovar, W. J. Salerno, A. Yoder, S. Richards, J. Rogers, J. R. Lupski, D. M. Muzny, R. A. Gibbs O57 Development of PacBio long range capture for detection of pathogenic structural variants Q. Meng, M. Bainbridge, M. Wang, H. Doddapaneni, Y. Han, D. Muzny, R. Gibbs O58 Rhesus macaques exhibit more non-synonymous variation but greater impact of purifying selection than humans R. A. Harris, M. Raveenedran, C. Xue, M. Dahdouli, L. Cox, G. Fan, B. Ferguson, J. Hovarth, Z. Johnson, S. Kanthaswamy, M. Kubisch, M. Platt, D. Smith, E. Vallender, R. Wiseman, X. Liu, J. Below, D. Muzny, R. Gibbs, F. Yu, J. Rogers O59 Assessing RNA structure disruption induced by single-nucleotide variation J. Lin, Y. Zhang, Z. Ouyang P1 A meta-analysis of genome-wide association studies of mitochondrial dna copy number A. Moore, Z. Wang, J. Hofmann, M. Purdue, R. Stolzenberg-Solomon, S. Weinstein, D. Albanes, C.-S. Liu, W.-L. Cheng, T.-T. Lin, Q. Lan, N. Rothman, S. Berndt P2 Missense polymorphic genetic combinations underlying down syndrome susceptibility E. S. Chen P4 The evaluation of alteration of ELAM-1 expression in the endometriosis patients H. Bahrami, A. Khoshzaban, S. Heidari Keshal P5 Obesity and the incidence of apolipoprotein E polymorphisms in an assorted population from Saudi Arabia population K. K. R. Alharbi P6 Genome-associated personalized antithrombotical therapy for patients with high risk of thrombosis and bleeding M. Zhalbinova, A. Akilzhanova, S. Rakhimova, M. Bekbosynova, S. Myrzakhmetova P7 Frequency of Xmn1 polymorphism among sickle cell carrier cases in UAE population M. Matar P8 Differentiating inflammatory bowel diseases by using genomic data: dimension of the problem and network organization N. Mili, R. Molinari, Y. Ma, S. Guerrier P9 Vulnerability of genetic variants to the risk of autism among Saudi children N. Elhawary, M. Tayeb, N. Bogari, N. Qotb P10 Chromatin profiles from ex vivo purified dopaminergic neurons establish a promising model to support studies of neurological function and dysfunction S. A. McClymont, P. W. Hook, L. A. Goff, A. McCallion P11 Utilization of a sensitized chemical mutagenesis screen to identify genetic modifiers of retinal dysplasia in homozygous Nr2e3^rd7 mice Y. Kong, J. R. Charette, W. L. Hicks, J. K. Naggert, L. Zhao, P. M. Nishina P12 Ion torrent next generation sequencing of recessive polycystic kidney disease in Saudi patients B. M. Edrees, M. Athar, F. A. Al-Allaf, M. M. Taher, W. Khan, A. Bouazzaoui, N. A. Harbi, R. Safar, H. Al-Edressi, A. Anazi, N. Altayeb, M. A. Ahmed, K. Alansary, Z. Abduljaleel P13 Digital expression profiling of Purkinje neurons and dendrites in different subcellular compartments A. Kratz, P. Beguin, S. Poulain, M. Kaneko, C. Takahiko, A. Matsunaga, S. Kato, A. M. Suzuki, N. Bertin, T. Lassmann, R. Vigot, P. Carninci, C. Plessy, T. Launey P14 The evolution of imperfection and imperfection of evolution: the functional and functionless fractions of the human genome D. Graur P16 Species-independent identification of known and novel recurrent genomic entities in multiple cancer patients J. Friis-Nielsen, J. M. Izarzugaza, S. Brunak P18 Discovery of active gene modules which are densely conserved across multiple cancer types reveal their prognostic power and mutually exclusive mutation patterns B. S. Soibam P19 Whole exome sequencing of dysplastic leukoplakia tissue indicates sequential accumulation of somatic mutations from oral precancer to cancer D. Das, N. Biswas, S. Das, S. Sarkar, A. Maitra, C. Panda, P. Majumder P21 Epigenetic mechanisms of carcinogensis by hereditary breast cancer genes J. J. Gruber, N. Jaeger, M. Snyder P22 RNA direct: a novel RNA enrichment strategy applied to transcripts associated with solid tumors K. Patel, S. Bowman, T. Davis, D. Kraushaar, A. Emerman, S. Russello, N. Henig, C. Hendrickson P23 RNA sequencing identifies gene mutations for neuroblastoma K. Zhang P24 Participation of SFRP1 in the modulation of TMPRSS2-ERG fusion gene in prostate cancer cell lines M. Rodriguez-Dorantes, C. D. Cruz-Hernandez, C. D. P. Garcia-Tobilla, S. Solorzano-Rosales P25 Targeted Methylation Sequencing of Prostate Cancer N. Jäger, J. Chen, R. Haile, M. Hitchins, J. D. Brooks, M. Snyder P26 Mutant TPMT alleles in children with acute lymphoblastic leukemia from México City and Yucatán, Mexico S. Jiménez-Morales, M. Ramírez, J. Nuñez, V. Bekker, Y. Leal, E. Jiménez, A. Medina, A. Hidalgo, J. Mejía P28 Genetic modifiers of Alström syndrome J. Naggert, G. B. Collin, K. DeMauro, R. Hanusek, P. M. Nishina P31 Association of genomic variants with the occurrence of angiotensin-converting-enzyme inhibitor (ACEI)-induced coughing among Filipinos E. M. Cutiongco De La Paz, R. Sy, J. Nevado, P. Reganit, L. Santos, J. D. Magno, F. E. Punzalan , D. Ona , E. Llanes, R. L. Santos-Cortes , R. Tiongco, J. Aherrera, L. Abrahan, P. Pagauitan-Alan; Philippine Cardiogenomics Study Group P32 The use of “humanized” mouse models to validate disease association of a de novo GARS variant and to test a novel gene therapy strategy for Charcot-Marie-Tooth disease type 2D K. H. Morelli, J. S. Domire, N. Pyne, S. Harper, R. Burgess P34 Molecular regulation of chondrogenic human induced pluripotent stem cells M. A. Gari, A. Dallol, H. Alsehli, A. Gari, M. Gari, A. Abuzenadah P35 Molecular profiling of hematologic malignancies: implementation of a variant assessment algorithm for next generation sequencing data analysis and clinical reporting M. Thomas, M. Sukhai, S. Garg, M. Misyura, T. Zhang, A. Schuh, T. Stockley, S. Kamel-Reid P36 Accessing genomic evidence for clinical variants at NCBI S. Sherry, C. Xiao, D. Slotta, K. Rodarmer, M. Feolo, M. Kimelman, G. Godynskiy, C. O’Sullivan, E. Yaschenko P37 NGS-SWIFT: a cloud-based variant analysis framework using control-accessed sequencing data from DBGAP/SRA C. Xiao, E. Yaschenko, S. Sherry P38 Computational assessment of drug induced hepatotoxicity through gene expression profiling C. Rangel-Escareño, H. Rueda-Zarate P40 Flowr: robust and efficient pipelines using a simple language-agnostic approach;ultraseq; fast modular pipeline for somatic variation calling using flowr S. Seth, S. Amin, X. Song, X. Mao, H. Sun, R. G. Verhaak, A. Futreal, J. Zhang P41 Applying “Big data” technologies to the rapid analysis of heterogenous large cohort data S. J. Whiite, T. Chiang, A. English, J. Farek, Z. Kahn, W. Salerno, N. Veeraraghavan, E. Boerwinkle, R. Gibbs P42 FANTOM5 web resource for the large-scale genome-wide transcription start site activity profiles of wide-range of mammalian cells T. Kasukawa, M. Lizio, J. Harshbarger, S. Hisashi, J. Severin, A. Imad, S. Sahin, T. C. Freeman, K. Baillie, A. Sandelin, P. Carninci, A. R. R. Forrest, H. Kawaji, The FANTOM Consortium P43 Rapid and scalable typing of structural variants for disease cohorts W. Salerno, A. English, S. N. Shekar, A. Mangubat, J. Bruestle, E. Boerwinkle, R. A. Gibbs P44 Polymorphism of glutathione S-transferases and sulphotransferases genes in an Arab population A. H. Salem, M. Ali, A. Ibrahim, M. Ibrahim P46 Genetic divergence of CYP3A5*3 pharmacogenomic marker for native and admixed Mexican populations J. C. Fernandez-Lopez, V. Bonifaz-Peña, C. Rangel-Escareño, A. Hidalgo-Miranda, A. V. Contreras P47 Whole exome sequence meta-analysis of 13 white blood cell, red blood cell, and platelet traits L. Polfus, CHARGE and NHLBI Exome Sequence Project Working Groups P48 Association of adipoq gene with type 2 diabetes and related phenotypes in african american men and women: The jackson heart study S. Davis, R. Xu, S. Gebeab, P Riestra, A Gaye, R. Khan, J. Wilson, A. Bidulescu P49 Common variants in casr gene are associated with serum calcium levels in koreans S. H. Jung, N. Vinayagamoorthy, S. H. Yim, Y. J. Chung P50 Inference of multiple-wave population admixture by modeling decay of linkage disequilibrium with multiple exponential functions Y. Zhou, S. Xu P51 A Bayesian framework for generalized linear mixed models in genome-wide association studies X. Wang, V. Philip, G. Carter P52 Targeted sequencing approach for the identification of the genetic causes of hereditary hearing impairment A. A. Abuzenadah, M. Gari, R. Turki, A. Dallol P53 Identification of enhancer sequences by ATAC-seq open chromatin profiling A. Uyar, A. Kaygun, S. Zaman, E. Marquez, J. George, D. Ucar P54 Direct enrichment for the rapid preparation of targeted NGS libraries C. L. Hendrickson, A. Emerman, D. Kraushaar, S. Bowman, N. Henig, T. Davis, S. Russello, K. Patel P56 Performance of the Agilent D5000 and High Sensitivity D5000 ScreenTape assays for the Agilent 4200 Tapestation System R. Nitsche, L. Prieto-Lafuente P57 ClinVar: a multi-source archive for variant interpretation M. Landrum, J. Lee, W. Rubinstein, D. Maglott P59 Association of functional variants and protein physical interactions of human MUTY homolog linked with familial adenomatous polyposis and colorectal cancer syndrome Z. Abduljaleel, W. Khan, F. A. Al-Allaf, M. Athar , M. M. Taher, N. Shahzad P60 Modification of the microbiom constitution in the gut using chicken IgY antibodies resulted in a reduction of acute graft-versus-host disease after experimental bone marrow transplantation A. Bouazzaoui, E. Huber, A. Dan, F. A. Al-Allaf, W. Herr, G. Sprotte, J. Köstler, A. Hiergeist, A. Gessner, R. Andreesen, E. Holler P61 Compound heterozygous mutation in the LDLR gene in Saudi patients suffering severe hypercholesterolemia F. Al-Allaf, A. Alashwal, Z. Abduljaleel, M. Taher, A. Bouazzaoui, H. Abalkhail, A. Al-Allaf, R. Bamardadh, M. Athar

Arming embolic beads with anti-VEGF antibodies and controlling their release using LbL technology

Transarterial chemoembolization (TACE) is used to treat various types of hypervascular tumors such as hepatocellular carcinoma and renal cancer. However, embolization and blocking of blood vessels nourishing a tumor mass evokes an angiogenic response due to the secretion of vascular endothelial growth factor (VEGF), which results in the formation of new blood vessels and eventually limitation in therapeutic efficacy. The presented work investigates the feasibility of loading the clinically used embolic beads (DC Bead®) with Bevacizumab (BEV), an anti-VEGF antibody, and control its release kinetics via Layer-by-Layer (LbL) coating. This strategy has the aim to achieve high, localized and sustained concentrations of BEV at the tumor site and reduce drug exposure in the systemic circulation. High loading of BEV on lyophilized beads of about 76mg BEV/bead vial was achieved. LbL coating was carried out by depositing alternating layers of the biocompatible polymers alginate and poly-L-lysine. Coating was proven successful by monitoring the reversal of zeta potential after addition of each layer. Morphological changes of the bead surface before and after coating were illustrated using SEM imaging. Moreover, release profiles from different formulations were studied and results showed that optimizing the number of deposited layers effectively slows the release of BEV for three days. Activity of released BEV was studied in different 2D and 3D cell based assays. Released BEV fractions showed comparable activity to fresh BEV solution used as control after 3days. In conclusion, our results suggest the opportunity for loading anti-VEGF antibodies on commercially available embolic beads to increase the efficacy of TACE of hypervascular tumors.

Evaluation of three different families of bombesin receptor radioantagonists for targeted imaging and therapy of gastrin releasing peptide receptor (GRP-R) positive tumors

Two new classes of radiolabeled GRP receptor antagonists are studied and compared with the well-established statine-based receptor antagonist DOTA-4-amino-1-carboxymethylpiperidine-d-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2 (RM2, 1; DOTA:1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid; Sta:(3S,4S)-4-amino-3-hydroxy-6-methylheptanoic acid). The bombesin-based pseudopeptide DOTA-4-amino-1-carboxymethylpiperidine-d-Phe-Gln-Trp-Ala-Val-Gly-His-Leuψ(CHOH-CH2)-(CH2)2-CH3 (RM7, 2), and the methyl ester DOTA-4-amino-1-carboxymethylpiperidine-d-Phe-Gln-Trp-Ala-Val-Gly-His-Leu-OCH3 (ARBA05, 3) analogues are labeled with (111)In and evaluated in vitro in PC-3 cell line and in vivo in PC-3 tumor-bearing nude mice. Antagonist potency was assessed by immunofluorescence-based receptor internalization and Ca(2+) mobilization assays. The conjugates showed good binding affinity, the IC50 value of 2 (3.2 ± 1.8 nM) being 2 and 10 times lower than 1 and 3. Compared to (111)In-1, (111)In-2 showed higher uptake in target tissues such as pancreas (1.5 ± 0.5%IA/g and 39.8 ± 9.3%IA/g at 4 h, respectively), whereas the compounds had similar tumor uptake (11.5 ± 2.4%IA/g and 11.8 ± 3.9%IA/g at 4h, respectively). The displacement of the radioligand in vivo was different in different receptor positive organs and depended on the displacing peptide.

Oxidative in vitro folding of a cysteine deficient variant of the G protein-coupled neuropeptide Y receptor type 2 improves stability at high concentration

In vitro folding of G protein-coupled receptors into a detergent environment represents a promising strategy for obtaining sufficient amounts of functional receptor molecules for structural studies. Typically, these preparations exhibit a poor long-term stability especially at the required high protein concentration. Here, we report a protocol for the stabilization of the Escherichia coli-expressed and subsequently folded neuropeptide Y receptor type 2. We identified the free cysteines in the receptor as one major reason for intermolecular protein aggregation. Therefore, six out of the eight cysteine residues were mutated to alanine or serine without any significant loss of functionality of the receptor as demonstrated in cell culture models. Furthermore, the disulfide bond between the remaining two cysteines was irreversibly formed by applying oxidative in vitro folding. Applying this strategy, the stability of the functionally folded Y2 receptor could be increased to 20 days at a concentration of 15 μm in a micelle environment consisting of 1,2-diheptanoyl-sn-glycero-3-phosphocholine and n-dodecyl-ß-D-maltoside.

Factors associated with oxidative stress and cancer risk in the Breast and Prostate Cancer Cohort Consortium

Both endogenous factors (genomic variations) and exogenous factors (environmental exposures, lifestyle) impact the balance of reactive oxygen species (ROS). Variants of the ND3 (rs2853826; G10398A) gene of the mitochondrial genome, manganese superoxide dismutase (MnSOD; rs4880 Val16Ala) and glutathione peroxidase (GPX-1; rs1050450 Pro198Leu), are purported to have functional effects on regulation of ROS balance. In this study, we examined associations of breast and prostate cancer risks and survival with these variants, and interactions between rs4880-rs1050450, and alcohol consumption-rs2853826. Nested case-control studies were conducted in the Breast and Prostate Cancer Cohort Consortium (BPC3), consisting of nine cohorts. The analyses included over 10726 post-menopausal breast and 7532 prostate cancer cases with matched controls. Logistic regression models were used to evaluate associations with risk, and proportional hazard models were used for survival outcomes. We did not observe significant interactions between polymorphisms in MnSOD and GPX-1, or between mitochondrial polymorphisms and alcohol intake and risk of either breast (p-interaction of 0.34 and 0.98, respectively) or prostate cancer (p-interaction of 0.49 and 0.50, respectively). We observed a weak inverse association between prostate cancer risk and GPX-1 Leu198Leu carriers (OR 0.87, 95% CI 0.79-0.97, p = 0.01). Overall survival among women with breast cancer was inversely associated with G10398 carriers who consumed alcohol (HR 0.66 95% CI 0.49-0.88). Given the high power in our study, it is unlikely that interactions tested have more than moderate effects on breast or prostate cancer risk. Observed associations need both further epidemiological and biological confirmation.

Comparative expression of hCG β-genes in human trophoblast from early and late first-trimester placentas

Human chorionic gonadotropin (hCG) displays a major role in pregnancy initiation and progression and is involved in trophoblast differentiation and fusion. However, the site and the type of dimeric hCG production during the first trimester of pregnancy is poorly known. At that time, trophoblastic plugs present in the uterine arteries disappear, allowing unrestricted flow of maternal blood to the intervillous space. The consequence is an important modification of the trophoblast environment, including a rise of oxygen levels from about 2.5% before 10 wk of amenorrhea (WA) to ∼8% after 12 WA. Two specific β-hCG proteins that differ from three amino acids have been described: type 1 (CGB7) and type 2 (CGB3, -5, and -8). Here, we demonstrated in situ and ex vivo on placental villi and in vitro in primary cultures of human cytotrophoblasts that type 1 and 2 β-hCG RNAs and proteins were expressed by trophoblasts and that these expressions were higher before blood enters in the intervillous space (8-9 vs. 12-14 WA). hCG was immunodetected in villous mononucleated cytotrophoblasts (VCT) and syncytiotrophoblast (ST) at 8-9 WA but only in ST at 12-14 WA. Furthermore, hCG secretion was fourfold higher in VCT cultures from 8-9 WA compared with 12-14 WA. Interestingly, VCT from 8-9 WA placentas were found to exhibit more fusion features. Taken together, we showed that type 1 and type 2 β-hCG are highly expressed by VCT in the early first trimester, contributing to the high levels of hCG found in maternal serum at this term.

[Early in-the-bag spontaneous intraocular lens dislocation of hydrophilic acryl single piece lenses following uncomplicated phacoemulsification]

BACKGROUND

As techniques for cataract surgery have evolved, spontaneous intraocular lens (IOL) dislocation in patients with no ocular pathology arises less frequently. We present seven consecutive cases of uncomplicated cataract surgery with early in-the-bag spontaneous intraocular lens dislocation for which the same type of hydrophilic single piece lens was used.

MATERIAL AND METHODS

A retrospective analysis was conducted on seven cases involving patients with IOL dislocation who underwent uncomplicated cataract surgery within a period of 4 months (October 2010 to January 2011) using the same type of single piece IOL. The median age of the 7 patients was 73 years and IOL repositioning was performed after an average of 10 weeks.

RESULTS

Sulcus repositioning could be carried out in only five of the seven patients and IOL repositioning within the capsule was achieved in one patient. A second patient exhibited IOL dislocation after yttrium aluminium garnet (YAG) laser capsulotomy. Explantation of the IOL and sulcus implantation of another IOL type (Acrysof MA50 MB) was necessary for a third patient. A fourth case presented an angled IOL haptic and dislocation of the IOL in the sulcus position.

DISCUSSION

Even after uncomplicated cataract surgery, spontaneous in-the-bag IOL dislocation in patients with no ocular pathology may occur due to a hydrophilic lens material which induces stronger anterior capsular phimosis (ACP) in comparison to alternative materials. In combination with a thin lens design this may result in angled IOL haptics and IOL dislocation.

CONCLUSIONS

Careful selection of suitable lens design and material according to individual predisposing factors is necessary. This retrospective case study demonstrates that the combination of hydrophilic lens material and a thin lens design may result in early spontaneous IOL dislocation. Furthermore, as established in one case, YAG laser capsulotomy may induce IOL dislocation if the lens design cannot withstand capsular fibrosis.