LENS: Landscape of Effective Neoantigens Software

MOTIVATION

Elimination of cancer cells by T cells is a critical mechanism of anti-tumor immunity and cancer immunotherapy response. T cells recognize cancer cells by engagement of T cell receptors with peptide epitopes presented by major histocompatibility complex molecules on the cancer cell surface. Peptide epitopes can be derived from antigen proteins coded for by multiple genomic sources. Bioinformatics tools used to identify tumor-specific epitopes via analysis of DNA and RNA-sequencing data have largely focused on epitopes derived from somatic variants, though a smaller number have evaluated potential antigens from other genomic sources.

RESULTS

We report here an open-source workflow utilizing the Nextflow DSL2 workflow manager, Landscape of Effective Neoantigens Software (LENS), which predicts tumor-specific and tumor-associated antigens from single nucleotide variants, insertions and deletions, fusion events, splice variants, cancer-testis antigens, overexpressed self-antigens, viruses, and endogenous retroviruses. The primary advantage of LENS is that it expands the breadth of genomic sources of discoverable tumor antigens using genomics data. Other advantages include modularity, extensibility, ease of use, and harmonization of relative expression level and immunogenicity prediction across multiple genomic sources. We present an analysis of 115 acute myeloid leukemia samples to demonstrate the utility of LENS. We expect LENS will be a valuable platform and resource for T cell epitope discovery bioinformatics, especially in cancers with few somatic variants where tumor-specific epitopes from alternative genomic sources are an elevated priority.

AVAILABILITY AND IMPLEMENTATION

More information about LENS, including code, workflow documentation, and instructions, can be found at (https://gitlab.com/landscape-of-effective-neoantigens-software).

NeoSplice: a bioinformatics method for prediction of splice variant neoantigens

Motivation

Splice variant neoantigens are a potential source of tumor-specific antigen (TSA) that are shared between patients in a variety of cancers, including acute myeloid leukemia. Current tools for genomic prediction of splice variant neoantigens demonstrate promise. However, many tools have not been well validated with simulated and/or wet lab approaches, with no studies published that have presented a targeted immunopeptidome mass spectrometry approach designed specifically for identification of predicted splice variant neoantigens.

Results

In this study, we describe NeoSplice, a novel computational method for splice variant neoantigen prediction based on (i) prediction of tumor-specific k-mers from RNA-seq data, (ii) alignment of differentially expressed k-mers to the splice graph and (iii) inference of the variant transcript with MHC binding prediction. NeoSplice demonstrates high sensitivity and precision (>80% on average across all splice variant classes) through in silico simulated RNA-seq data. Through mass spectrometry analysis of the immunopeptidome of the K562.A2 cell line compared against a synthetic peptide reference of predicted splice variant neoantigens, we validated 4 of 37 predicted antigens corresponding to 3 of 17 unique splice junctions. Lastly, we provide a comparison of NeoSplice against other splice variant prediction tools described in the literature. NeoSplice provides a well-validated platform for prediction of TSA vaccine targets for future cancer antigen vaccine studies to evaluate the clinical efficacy of splice variant neoantigens.

Availability and implementation

https://github.com/Benjamin-Vincent-Lab/NeoSplice.

Supplementary information

Supplementary data are available at Bioinformatics Advances online.

Entinostat induces antitumor immune responses through immune editing of tumor neoantigens

Although immune-checkpoint inhibitors (ICIs) have been a remarkable advancement in bladder cancer treatment, the response rate to single-agent ICIs remains suboptimal. There has been substantial interest in the use of epigenetic agents to enhance ICI efficacy, although precisely how these agents potentiate ICI response has not been fully elucidated. We identified entinostat, a selective HDAC1/3 inhibitor, as a potent antitumor agent in our immune-competent bladder cancer mouse models (BBN963 and BBN966). We demonstrate that entinostat selectively promoted immune editing of tumor neoantigens, effectively remodeling the tumor immune microenvironment, resulting in a robust antitumor response that was cell autonomous, dependent upon antigen presentation, and associated with increased numbers of neoantigen-specific T cells. Finally, combination treatment with anti-PD-1 and entinostat led to complete responses and conferred long-term immunologic memory. Our work defines a tumor cell-autonomous mechanism of action for entinostat and a strong preclinical rationale for the combined use of entinostat and PD-1 blockade in bladder cancer.

Landscape and selection of vaccine epitopes in SARS-CoV-2

BACKGROUND

Early in the pandemic, we designed a SARS-CoV-2 peptide vaccine containing epitope regions optimized for concurrent B cell, CD4+ T cell, and CD8+ T cell stimulation. The rationale for this design was to drive both humoral and cellular immunity with high specificity while avoiding undesired effects such as antibody-dependent enhancement (ADE).

METHODS

We explored the set of computationally predicted SARS-CoV-2 HLA-I and HLA-II ligands, examining protein source, concurrent human/murine coverage, and population coverage. Beyond MHC affinity, T cell vaccine candidates were further refined by predicted immunogenicity, sequence conservation, source protein abundance, and coverage of high frequency HLA alleles. B cell epitope regions were chosen from linear epitope mapping studies of convalescent patient serum, followed by filtering for surface accessibility, sequence conservation, spatial localization near functional domains of the spike glycoprotein, and avoidance of glycosylation sites.

RESULTS

From 58 initial candidates, three B cell epitope regions were identified. From 3730 (MHC-I) and 5045 (MHC-II) candidate ligands, 292 CD8+ and 284 CD4+ T cell epitopes were identified. By combining these B cell and T cell analyses, as well as a manufacturability heuristic, we proposed a set of 22 SARS-CoV-2 vaccine peptides for use in subsequent murine studies. We curated a dataset of ~ 1000 observed T cell epitopes from convalescent COVID-19 patients across eight studies, showing 8/15 recurrent epitope regions to overlap with at least one of our candidate peptides. Of the 22 candidate vaccine peptides, 16 (n = 10 T cell epitope optimized; n = 6 B cell epitope optimized) were manually selected to decrease their degree of sequence overlap and then synthesized. The immunogenicity of the synthesized vaccine peptides was validated using ELISpot and ELISA following murine vaccination. Strong T cell responses were observed in 7/10 T cell epitope optimized peptides following vaccination. Humoral responses were deficient, likely due to the unrestricted conformational space inhabited by linear vaccine peptides.

CONCLUSIONS

Overall, we find our selection process and vaccine formulation to be appropriate for identifying T cell epitopes and eliciting T cell responses against those epitopes. Further studies are needed to optimize prediction and induction of B cell responses, as well as study the protective capacity of predicted T and B cell epitopes.

CD28 costimulation drives tumor-infiltrating T cell glycolysis to promote inflammation

Metabolic reprogramming dictates the fate and function of stimulated T cells, yet these pathways can be suppressed in T cells in tumor microenvironments. We previously showed that glycolytic and mitochondrial adaptations directly contribute to reducing the effector function of renal cell carcinoma (RCC) CD8+ tumor-infiltrating lymphocytes (TILs). Here we define the role of these metabolic pathways in the activation and effector functions of CD8+ RCC TILs. CD28 costimulation plays a key role in augmenting T cell activation and metabolism, and is antagonized by the inhibitory and checkpoint immunotherapy receptors CTLA4 and PD-1. While RCC CD8+ TILs were activated at a low level when stimulated through the T cell receptor alone, addition of CD28 costimulation greatly enhanced activation, function, and proliferation. CD28 costimulation reprogrammed RCC CD8+ TIL metabolism with increased glycolysis and mitochondrial oxidative metabolism, possibly through upregulation of GLUT3. Mitochondria also fused to a greater degree, with higher membrane potential and overall mass. These phenotypes were dependent on glucose metabolism, as the glycolytic inhibitor 2-deoxyglucose both prevented changes to mitochondria and suppressed RCC CD8+ TIL activation and function. These data show that CD28 costimulation can restore RCC CD8+ TIL metabolism and function through rescue of T cell glycolysis that supports mitochondrial mass and activity.

Abstract 2866: Neoantigen nanovaccine improves personalized cancer immunotherapy

Background: Neoantigens are attractive targets for personalized anti-tumor vaccination, given their uniqueness to the tumor and the ability to bypass immune tolerance. Recently, the feasibility of neoantigen vaccine has been demonstrated in patients. However, the response rate of neoantigen vaccines is unsatisfied because of their low immunogenicity, undesired degradation, limited cross-presentation, and acquired resistance. Here, we developed a nanoparticle-based neoantigen vaccine system to overcome these challenges.

Methods: We predicted both MHC Class I and Class II neoantigen peptides for B16-F10 melanoma model using a bioinformatics pipeline. We screened an optimal incorporation strategy to formulate nanovaccines by either directly absorbing neoantigen peptides on PLGA nanoparticle (NP) or conjugating them to PEG-PLGA through a pH-responsive strategy or a redox-responsive strategy. We formulated nanovaccine with redox-responsive neoantigen-polymer conjugates and a STING agonist DMXAA. C57/BL6 mice were inoculated with 50,000 B16-F10 tumor cells on their right flank. Mice were vaccinated subcutaneously on their left flank with different nanovaccines or control arms on day 4, 8 and 12 after tumor inoculation. Mice were given anti-PD1 (200 μg, intraperitoneally) on day 4, 8, 12, 16, 20 after tumor inoculation. Tumor volume and mice survival were recorded. We also evaluated the immune related cytokines in mouse blood on day 15 after treatment.

Results: Four MHC I and three MHC II neoantigen peptides were screened out for B16-F10 melanoma with high IFN-γ immune response. Results indicate that a redox conjugation strategy using PLGA-PEG and SPDP linker were more efficient in tumor inhibition than other incorporation strategies for our neoantigen peptides. By formulating nanovaccine with redox-responsive neoantigen-polymer conjugates and a STING agonist, we demonstrated that our nanovaccine, when combined with αPD1, achieved a 50% survival rate on day 38, compared to 0% of PBS treated group and 20% of non-formulated neoantigen peptides treated group. To confirm the enhanced immunity, we evaluated the immune related cytokines in mouse blood on day 15 after treatment. We found that our neoantigen nanovaccine achieved the highest expression of immune related cytokines among all arms, indicating that our nanovaccine induced higher immune response than non-formulated neoantigen peptides or other NP strategies.

Conclusions: We demonstrate that our nanovaccine achieves increased therapeutic efficacy and higher expression of immune related cytokines than non-formulated neoantigen peptides. Our work develops a novel nanoparticle-based neoantigen vaccine that will improve current personalized cancer immunotherapy.

Citation Format: Yu Mi, Christof C. Smith, Jonathan S. Serody, Benjamin G. Vincent, Andrew Z. Wang, Hyesun Hyun. Neoantigen nanovaccine improves personalized cancer immunotherapy [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 2866.

Landscape and Selection of Vaccine Epitopes in SARS-CoV-2

There is an urgent need for a vaccine with efficacy against SARS-CoV-2. We hypothesize that peptide vaccines containing epitope regions optimized for concurrent B cell, CD4+ T cell, and CD8+ T cell stimulation would drive both humoral and cellular immunity with high specificity, potentially avoiding undesired effects such as antibody-dependent enhancement (ADE). Additionally, such vaccines can be rapidly manufactured in a distributed manner. In this study, we combine computational prediction of T cell epitopes, recently published B cell epitope mapping studies, and epitope accessibility to select candidate peptide vaccines for SARS-CoV-2. We begin with an exploration of the space of possible T cell epitopes in SARS-CoV-2 with interrogation of predicted HLA-I and HLA-II ligands, overlap between predicted ligands, protein source, as well as concurrent human/murine coverage. Beyond MHC affinity, T cell vaccine candidates were further refined by predicted immunogenicity, viral source protein abundance, sequence conservation, coverage of high frequency HLA alleles and co-localization of CD4+ and CD8+ T cell epitopes. B cell epitope regions were chosen from linear epitope mapping studies of convalescent patient serum, followed by filtering to select regions with surface accessibility, high sequence conservation, spatial localization near functional domains of the spike glycoprotein, and avoidance of glycosylation sites. From 58 initial candidates, three B cell epitope regions were identified. By combining these B cell and T cell analyses, as well as a manufacturability heuristic, we propose a set of SARS-CoV-2 vaccine peptides for use in subsequent murine studies and clinical trials.

Targeting metabolic dysregulation of T cells in kidney cancer

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Background: Cancer cells can inhibit effector T cells through both immunomodulatory receptors and alteration of the tumor microenvironment. Rather than efficient use of aerobic glycolysis by activated effector T cells, Renal Cell Carcinoma (RCC) infiltrating T cells (TIL) fail to increase glucose metabolism, and instead display increased reactive oxygen species (ROS) and mitochondrial dysfunction. CD8 RCC TIL also have notable differences in mitochondrial morphology compared to healthy control CD8 T cells and were punctate and dispersed rather than fused in networks. Here we test if RCC TIL can be re-activated and identify metabolic requirements for inflammatory TIL function. Methods: De-identified samples from tumor or adjacent normal tissue donations from patients with RCC were collected under an approved IRB protocol and processed into single cell suspensions of tumor and associated cells by mechanical dissociation to test TIL activation and metabolic requirements upon in vitro re-stimulation. Results: RNA-seq data suggested that CD8 from TIL rely on distinct metabolic pathways compared to control. While control T cells increased effector cytokine production and glycolysis with antigen receptor alone and further augmented this pathway with co-stimulation, single cell RNAseq showed that CD8 RCC TIL required co-stimulation for this transition. Co-stimulation can promote T cell glycolysis and we found antigen receptor stimulation with CD28-mediated co-stimulation increased function of CD8 RCC TIL as indicated by increased surface markers of activation and IFNγproduction. This was accompanied by rescue of metabolic markers, including increased mitochondrial mass and markers of electron transport. Improved functional capacity was dependent upon glycolysis because inhibition with 2-deoxyglucose limited CD8 RCC TIL activation following CD28 co-stimulation. Conclusions: Bypassing metabolic defects restore markers of TIL activation and effector function.These datademonstrate that CD8 RCC TIL can be functionally restored but that this requires the ability to increase glucose metabolism. These findings may allow for combined therapies to improve response rates of checkpoint inhibition in this disease.

Evaluation of the NuCLEUS-X™ balloon valvuloplasty catheter for severe pulmonic stenosis in dogs

INTRODUCTION/OBJECTIVES

Balloon instability is commonly encountered during balloon pulmonary valvuloplasty (BPV) and may result in an unsuccessful procedure. The NuCLEUS-X™ catheter is a recently developed BPV catheter with a unique barbell shape and an ordered pattern of inflation that stabilizes the balloon to span the valve annulus before expansion of the balloon center.

ANIMALS

Ten client-owned dogs with severe valvular pulmonic stenosis (PS).

MATERIALS AND METHODS

Prospective observational study. The BPV procedure was performed by standard technique with use of NuCLEUS-X™ catheters targeting a balloon-to-annulus ratio between 1.2 and 1.5. Balloon stability, safety, and procedural success were assessed. Procedural success was defined as either a reduction in the Doppler transpulmonic PG by at least 50% of the pre-procedural PG or <80 mmHg one month post procedure.

RESULTS

Balloon stability centered at the pulmonic valve on the first inflation was achieved in 10/10 cases. The mean PG before BPV was 141 mmHg ±41 mmHg, and the PG after BPV at one month was 83 mmHg ±41 mmHg. Procedural success was achieved in 56% of patients. All dogs survived the BPV, and no major procedural complications were encountered using the NuCLEUS-X™ catheter.

CONCLUSIONS

The use of the NuCLEUS-X™ catheter is feasible for BPV in dogs with severe PS. The unique balloon shape provided catheter stability on the first inflation in all dogs, which may be beneficial when stabilization of a conventional BPV catheter cannot be achieved.

Using RNA Sequencing to Characterize the Tumor Microenvironment

RNA sequencing (RNA-seq) is an integral tool in immunogenomics, allowing for interrogation of the transcriptome of a tumor and its microenvironment. Analytical methods to deconstruct the genomics data can then be applied to infer gene expression patterns associated with the presence of various immunocyte populations. High quality RNA-seq is possible from formalin-fixed, paraffin-embedded (FFPE), fresh-frozen, and fresh tissue, with a wide variety of sequencing library preparation methods, sequencing platforms, and downstream bioinformatics analyses currently available. Selection of an appropriate library preparation method is largely determined by tissue type, quality of RNA, and quantity of RNA. Downstream of sequencing, many analyses can be applied to the data, including differential gene expression analysis, immune gene signature analysis, gene pathway analysis, T/B-cell receptor inference, HLA inference, and viral transcript quantification. In this chapter, we will describe our workflow for RNA-seq from bulk tissue to evaluable data, including extraction of RNA, library preparation methods, sequencing of libraries, alignment and quality assurance of data, and initial downstream analyses of RNA-seq data to extract relevant immunogenomics features. Systems biology methods that draw additional insights by integrating these features are covered further in Chapters 28 - 30 .

The dysfunction of BP180/collagen XVII in keratinocytes promotes melanoma progression

BP180, also termed collagen XVII, is a hemidesmosomal transmembrane glycoprotein expressed in basal keratinocytes, and functions as a cell-matrix adhesion molecule in the dermal-epidermal junction of the skin. Its function, other than cell-matrix adhesion, remains unclear. We generated a mouse strain with BP180 dysfunction (termed ∆NC16A), which develops spontaneous skin inflammation accompanied by an influx of myeloid derived suppressor cells (MDSCs). We used the B16 mouse melanoma model to demonstrate that BP180 dysfunction in either skin or basal keratinocytes promotes MDSC influx into skin and tumor progression. MDSC depletion reduced tumor progression in ∆NC16A mice, demonstrating a critical role for BP180 dysfunction-driven MDSCs in melanoma progression. This study provides the first direct evidence that BP180, a cell-cell matrix adhesion molecule, possesses antitumor function through modulating infiltration of MDSCs. Basal keratinocytes actively participate in skin microenvironment changes caused by BP180 dysfunction. ∆NC16A mice could be a new animal model to study the melanoma microenvironment.

A High-Avidity T-cell Receptor Redirects Natural Killer T-cell Specificity and Outcompetes the Endogenous Invariant T-cell Receptor

T-cell receptor (TCR) gene transfer redirects T cells to target intracellular antigens. However, the potential autoreactivity generated by TCR mispairing and occurrence of graft-versus-host disease in the allogenic setting due to the retention of native TCRs remain major concerns. Natural killer T cells (NKT) have shown promise as a platform for adoptive T-cell therapy in cancer patients. Here, we showed their utility for TCR gene transfer. We successfully engineered and expanded NKTs expressing a functional TCR (TCR NKTs), showing HLA-restricted antitumor activity in xenogeneic mouse models in the absence of graft-versus-mouse reactions. We found that TCR NKTs downregulated the invariant TCR (iTCR), leading to iTCR⁺TCR⁺ and iTCR^-TCR⁺ populations. In-depth analyses of these subsets revealed that in iTCR^-TCR⁺ NKTs, the iTCR, although expressed at the mRNA and protein levels, was retained in the cytoplasm. This effect resulted from a competition for binding to CD3 molecules for cell-surface expression by the transgenic TCR. Overall, our results highlight the feasibility and advantages of using NKTs for TCR expression for adoptive cell immunotherapies. NKT-low intrinsic alloreactivity that associated with the observed iTCR displacement by the engineered TCR represents ideal characteristics for "off-the-shelf" products without further TCR gene editing.

Machine-Learning Prediction of Tumor Antigen Immunogenicity in the Selection of Therapeutic Epitopes

Current tumor neoantigen calling algorithms primarily rely on epitope/major histocompatibility complex (MHC) binding affinity predictions to rank and select for potential epitope targets. These algorithms do not predict for epitope immunogenicity using approaches modeled from tumor-specific antigen data. Here, we describe peptide-intrinsic biochemical features associated with neoantigen and minor histocompatibility mismatch antigen immunogenicity and present a gradient boosting algorithm for predicting tumor antigen immunogenicity. This algorithm was validated in two murine tumor models and demonstrated the capacity to select for therapeutically active antigens. Immune correlates of neoantigen immunogenicity were studied in a pan-cancer data set from The Cancer Genome Atlas and demonstrated an association between expression of immunogenic neoantigens and immunity in colon and lung adenocarcinomas. Lastly, we present evidence for expression of an out-of-frame neoantigen that was capable of driving antitumor cytotoxic T-cell responses. With the growing clinical importance of tumor vaccine therapies, our approach may allow for better selection of therapeutically relevant tumor-specific antigens, including nonclassic out-of-frame antigens capable of driving antitumor immunity.

Alternative tumour-specific antigens

The study of tumour-specific antigens (TSAs) as targets for antitumour therapies has accelerated within the past decade. The most commonly studied class of TSAs are those derived from non-synonymous single-nucleotide variants (SNVs), or SNV neoantigens. However, to increase the repertoire of available therapeutic TSA targets, 'alternative TSAs', defined here as high-specificity tumour antigens arising from non-SNV genomic sources, have recently been evaluated. Among these alternative TSAs are antigens derived from mutational frameshifts, splice variants, gene fusions, endogenous retroelements and other processes. Unlike the patient-specific nature of SNV neoantigens, some alternative TSAs may have the advantage of being widely shared by multiple tumours, allowing for universal, off-the-shelf therapies. In this Opinion article, we will outline the biology, available computational tools, preclinical and/or clinical studies and relevant cancers for each alternative TSA class, as well as discuss both current challenges preventing the therapeutic application of alternative TSAs and potential solutions to aid in their clinical translation.

Prognostic value of B cells in cutaneous melanoma

Background

Measures of the adaptive immune response have prognostic and predictive associations in melanoma and other cancer types. Specifically, intratumoral T cell density and function have considerable prognostic and predictive value in skin cutaneous melanoma (SKCM). Less is known about the significance of tumor-infiltrating B cells in SKCM. Our goal was to understand the prognostic and predictive value of B cell phenotypic subsets in SKCM using RNA sequencing.

Methods

We used our previously published algorithm, V’DJer, to assemble B cell receptor (BCR) repertoires and estimate diversity from short-read RNA sequencing (RNA-seq). We applied machine learning-based cellular phenotype classifiers to measure relative similarity of bulk tumor sample gene expression profiles and different B cell phenotypes. We assessed these aspects of B cell biology in 473 SKCM from the Cancer Genome Atlas Project (TCGA) as well as in RNA-seq data corresponding to tumor samples procured from patients who received CTLA-4 and PD-1 inhibitors for metastatic SKCM.

Results

We found that the BCR repertoire was associated with different clinical factors, such as tumor tissue site and sex. However, increased clonality of the BCR repertoire was favorably prognostic in SKCM and was prognostic even after first conditioning on various clinical factors. Mutation burden was not correlated with any BCR measurement, and no specific mutation had an altered BCR repertoire. Lack of an assembled BCR in pre-treatment tumor tissues was associated with a lack of anti-tumor response to a CTLA-4 inhibitor in metastatic SKCM.

Conclusions

These findings suggest an important prognostic and predictive role for B cell characteristics in SKCM. This has implications for melanoma immunobiology and potential development of immunogenomics features to predict survival and response to immunotherapy.

Electronic supplementary material

The online version of this article (10.1186/s13073-019-0647-5) contains supplementary material, which is available to authorized users.

Endogenous retroviral signatures predict immunotherapy response in clear cell renal cell carcinoma

Human endogenous retroviruses (hERVs) are remnants of exogenous retroviruses that have integrated into the genome throughout evolution. We developed a computational workflow, hervQuant, which identified more than 3,000 transcriptionally active hERVs within The Cancer Genome Atlas (TCGA) pan-cancer RNA-Seq database. hERV expression was associated with clinical prognosis in several tumor types, most significantly clear cell renal cell carcinoma (ccRCC). We explored two mechanisms by which hERV expression may influence the tumor immune microenvironment in ccRCC: (i) RIG-I-like signaling and (ii) retroviral antigen activation of adaptive immunity. We demonstrated the ability of hERV signatures associated with these immune mechanisms to predict patient survival in ccRCC, independent of clinical staging and molecular subtyping. We identified potential tumor-specific hERV epitopes with evidence of translational activity through the use of a ccRCC ribosome profiling (Ribo-Seq) dataset, validated their ability to bind HLA in vitro, and identified the presence of MHC tetramer-positive T cells against predicted epitopes. hERV sequences identified through this screening approach were significantly more highly expressed in ccRCC tumors responsive to treatment with programmed death receptor 1 (PD-1) inhibition. hervQuant provides insights into the role of hERVs within the tumor immune microenvironment, as well as evidence that hERV expression could serve as a biomarker for patient prognosis and response to immunotherapy.

Endogenous retrovirus expression is associated with response to immune checkpoint blockade in clear cell renal cell carcinoma

Although a subset of clear cell renal cell carcinoma (ccRCC) patients respond to immune checkpoint blockade (ICB), predictors of response remain uncertain. We investigated whether abnormal expression of endogenous retroviruses (ERVs) in tumors is associated with local immune checkpoint activation (ICA) and response to ICB. Twenty potentially immunogenic ERVs (πERVs) were identified in ccRCC in The Cancer Genome Atlas data set, and tumors were stratified into 3 groups based on their expression levels. πERV-high ccRCC tumors showed increased immune infiltration, checkpoint pathway upregulation, and higher CD8+ T cell fraction in infiltrating leukocytes compared with πERV-low ccRCC tumors. Similar results were observed in ER+/HER2- breast, colon, and head and neck squamous cell cancers. ERV expression correlated with expression of genes associated with histone methylation and chromatin regulation, and πERV-high ccRCC was enriched in BAP1 mutant tumors. ERV3-2 expression correlated with ICA in 11 solid cancers, including the 4 named above. In a small retrospective cohort of 24 metastatic ccRCC patients treated with single-agent PD-1/PD-L1 blockade, ERV3-2 expression in tumors was significantly higher in responders compared with nonresponders. Thus, abnormal expression of πERVs is associated with ICA in several solid cancers, including ccRCC, and ERV3-2 expression is associated with response to ICB in ccRCC.

CD30-Redirected Chimeric Antigen Receptor T Cells Target CD30+ and CD30- Embryonal Carcinoma via Antigen-Dependent and Fas/FasL Interactions

Tumor antigen heterogeneity limits success of chimeric antigen receptor (CAR) T-cell therapies. Embryonal carcinomas (EC) and mixed testicular germ cell tumors (TGCT) containing EC, which are the most aggressive TGCT subtypes, are useful for dissecting this issue as ECs express the CD30 antigen but also contain CD30^-/dim cells. We found that CD30-redirected CAR T cells (CD30.CAR T cells) exhibit antitumor activity in vitro against the human EC cell lines Tera-1, Tera-2, and NCCIT and putative EC stem cells identified by Hoechst dye staining. Cytolytic activity of CD30.CAR T cells was complemented by their sustained proliferation and proinflammatory cytokine production. CD30.CAR T cells also demonstrated antitumor activity in an in vivo xenograft NOD/SCID/γcnull (NSG) mouse model of metastatic EC. We observed that CD30.CAR T cells, while targeting CD30⁺ EC tumor cells through the CAR (i.e., antigen-dependent targeting), also eliminated surrounding CD30^- EC cells in an antigen-independent manner, via a cell-cell contact-dependent Fas/FasL interaction. In addition, ectopic Fas (CD95) expression in CD30⁺ Fas^- EC was sufficient to improve CD30.CAR T-cell antitumor activity. Overall, these data suggest that CD30.CAR T cells might be useful as an immunotherapy for ECs. Additionally, Fas/FasL interaction between tumor cells and CAR T cells can be exploited to reduce tumor escape due to heterogeneous antigen expression or to improve CAR T-cell antitumor activity. Cancer Immunol Res; 6(10); 1274-87. ©2018 AACR.

A Dual Immunotherapy Nanoparticle Improves T-Cell Activation and Cancer Immunotherapy

Combination immunotherapy has recently emerged as a powerful cancer treatment strategy. A promising treatment approach utilizes coadministration of antagonistic antibodies to block checkpoint inhibitor receptors, such as antiprogrammed cell death-1 (aPD1), alongside agonistic antibodies to activate costimulatory receptors, such as antitumor necrosis factor receptor superfamily member 4 (aOX40). Optimal T-cell activation is achieved when both immunomodulatory agents simultaneously engage T-cells and promote synergistic proactivation signaling. However, standard administration of these therapeutics as free antibodies results in suboptimal T-cell binding events, with only a subset of the T-cells binding to both aPD1 and aOX40. Here, it is shown that precise spatiotemporal codelivery of aPD1 and aOX40 using nanoparticles (NP) (dual immunotherapy nanoparticles, DINP) results in improved T-cell activation, enhanced therapeutic efficacy, and increased immunological memory. It is demonstrated that DINP elicits higher rates of T-cell activation in vitro than free antibodies. Importantly, it is demonstrated in two tumor models that combination immunotherapy administered in the form of DINP is more effective than the same regimen administered as free antibodies. This work demonstrates a novel strategy to improve combination immunotherapy using nanotechnology.

Molecular Subtype-Specific Immunocompetent Models of High-Grade Urothelial Carcinoma Reveal Differential Neoantigen Expression and Response to Immunotherapy

High-grade urothelial cancer contains intrinsic molecular subtypes that exhibit differences in underlying tumor biology and can be divided into luminal-like and basal-like subtypes. We describe here the first subtype-specific murine models of bladder cancer and show that Upk3a-Cre^ERT2; Trp53^L/L; Pten^L/L; Rosa26^LSL-Luc (UPPL, luminal-like) and BBN (basal-like) tumors are more faithful to human bladder cancer than the widely used MB49 cells. Following engraftment into immunocompetent C57BL/6 mice, BBN tumors were more responsive to PD-1 inhibition than UPPL tumors. Responding tumors within the BBN model showed differences in immune microenvironment composition, including increased ratios of CD8⁺:CD4⁺ and memory:regulatory T cells. Finally, we predicted and confirmed immunogenicity of tumor neoantigens in each model. These UPPL and BBN models will be a valuable resource for future studies examining bladder cancer biology and immunotherapy.Significance: This work establishes human-relevant mouse models of bladder cancer. Cancer Res; 78(14); 3954-68. ©2018 AACR.

The Cancer Genome Atlas Comprehensive Molecular Characterization of Renal Cell Carcinoma

Renal cell carcinoma (RCC) is not a single disease, but several histologically defined cancers with different genetic drivers, clinical courses, and therapeutic responses. The current study evaluated 843 RCC from the three major histologic subtypes, including 488 clear cell RCC, 274 papillary RCC, and 81 chromophobe RCC. Comprehensive genomic and phenotypic analysis of the RCC subtypes reveals distinctive features of each subtype that provide the foundation for the development of subtype-specific therapeutic and management strategies for patients affected with these cancers. Somatic alteration of BAP1, PBRM1, and PTEN and altered metabolic pathways correlated with subtype-specific decreased survival, while CDKN2A alteration, increased DNA hypermethylation, and increases in the immune-related Th2 gene expression signature correlated with decreased survival within all major histologic subtypes. CIMP-RCC demonstrated an increased immune signature, and a uniform and distinct metabolic expression pattern identified a subset of metabolically divergent (MD) ChRCC that associated with extremely poor survival.

Immuno-PET imaging of tumor-infiltrating lymphocytes using zirconium-89 radiolabeled anti-CD3 antibody in immune-competent mice bearing syngeneic tumors

The ability to non-invasively monitor tumor-infiltrating T cells in vivo could provide a powerful tool to visualize and quantify tumor immune infiltrates. For non-invasive evaluations in vivo, an anti-CD3 mAb was modified with desferrioxamine (DFO) and radiolabeled with zirconium-89 (Zr-89 or 89Zr). Radiolabeled 89Zr-DFO-anti-CD3 was tested for T cell detection using positron emission tomography (PET) in both healthy mice and mice bearing syngeneic bladder cancer BBN975. In vivo PET/CT and ex vivo biodistribution demonstrated preferential accumulation and visualization of tracer in the spleen, thymus, lymph nodes, and bone marrow. In tumor bearing mice, 89Zr-DFO-anti-CD3 demonstrated an 11.5-fold increase in tumor-to-blood signal compared to isotype control. Immunological profiling demonstrated no significant change to total T cell count, but observed CD4+ T cell depletion and CD8+ T cell expansion to the central and effector memory. This was very encouraging since a high CD8+ to CD4+ T cell ratio has already been associated with better patient prognosis. Ultimately, this anti-CD3 mAb allowed for in vivo imaging of homeostatic T cell distribution, and more specifically tumor-infiltrating T cells. Future applications of this radiolabeled mAb against CD3 could include prediction and monitoring of patient response to immunotherapy.

Molecular and Clinical Characterization of a Claudin-Low Subtype of Gastric Cancer

Purpose

Claudin-low molecular subtypes have been identified in breast and bladder cancers and are characterized by low expression of claudins, enrichment for epithelial-to-mesenchymal transition (EMT), and tumor-initiating cell (TIC) features. We evaluated whether the claudin-low subtype also exists in gastric cancer.

Materials and Methods

Four hundred fifteen tumors from The Cancer Genome Atlas (TCGA) gastric cancer mRNA data set were clustered on the claudin, EMT, and TIC gene sets to identify claudin-low tumors. We derived a 24-gene predictor that classifies gastric cancer into claudin-low and non–claudin-low subtypes. This predictor was validated with the Asian Cancer Research Group (ACRG) data set. We characterized molecular and clinical features of claudin-low tumors.

Results

We identified 46 tumors that had consensus enrichment for claudin-low features in TCGA data set. Claudin-low tumors were most commonly diffuse histologic type (82%) and originally classified as TCGA genomically stable (GS) subtype (78%). Compared with GS subtype, claudin-low subtype had significant activation in Rho family of GTPases signaling, which appears to play a key role in its EMT and TIC properties. In the ACRG data set, 28 of 300 samples were classified as claudin-low tumors by the 24-gene predictor and were phenotypically similar to the initially derived claudin-low tumors. Clinically, claudin-low subtype had the worst overall survival. Of note, the hazard ratios that compared claudin-low versus GS subtype were 2.10 (95% CI, 1.07 to 4.11) in TCGA and 2.32 (95% CI, 1.18 to 4.55) in the ACRG cohorts, with adjustment for age and pathologic stage.

Conclusion

We identified a gastric claudin-low subtype that carries a poor prognosis likely related to therapeutic resistance as a result of its EMT and TIC phenotypes.

Abstract 978: Spatial-temporal delivery of OX40 agonist and PD-1 inhibitor using nanoparticles improves therapeutic efficacy of cancer immunotherapy

Background: Cancer immunotherapy is an exciting new approach to cancer treatment and there is strong interest in strategies to improve the long-term durable response rates of cancer immunotherapy. One approach is to combine checkpoint inhibitors such as aPD-1 with T cell activator such as OX40 agonist to further increase immune activation. We hypothesized that we can improve the therapeutic efficacy of this approach by temporally control the activation of OX40 and inhibition of PD-1 pathways. To accomplish this, we utilized nanoparticles that can deliver anti-OX40 and anti-PD1 antibodies simultaneously to T cells.

Methods: Agonist antibody (anti-OX40) and antagonist antibody (anti-PD1) were conjugated to PLGA-PEG-Maleimide nanoparticles (AANPs) with precise ratio control and quantified by ELISA. Their specific binding to the target proteins was shown in vitro by flow cytometry. The tumor inhibition efficiency was assessed on mice bearing different tumor models. Two tumors were inoculated subcutaneously (105 B16F10 cells) or on fourth mammary fat pad (105 4T1 cells) on both flanks of mice. One side of tumor was irradiated once and AANPs were injected twice every 3 days. In vivo depletion experiments were tested on C56Bl6 mice and CD11b/c mice. Different populations of T cells in tumor and spleen were analyzed by flow cytometry and by fluorescent IHC staining. T cell killing assay and IFN-γ ELISpot were studied. Co-localization was demonstrated with fluorescent labeled antibodies and the corresponding AANPs.

Results: AANPs showed a 30% cure rate, compared to 10% of free antibodies, 0% of anti-PD1 conjugated NPs, and 0% of anti-OX40 conjugated NPs in B16F10 melanoma model. We then re-challenged the cured mice with 2×105 B16F10 cells and none of the mice developed another tumor. In 4T1 breast cancer model, the survival rate on day 39 was 50% with AANPs treatment, compared to 22% in the mixture of anti-PD1 conjugated nanoparticles and anti-OX40 conjugated nanoparticles, and 0% of free antibodies. We demonstrated that AANPs led to a higher medium TCD8+/Treg ratio in tumors. The therapeutic effect was mediated by CD8+ T cells as elimination of these cells abrogated the therapeutic effects. In vitro study confirmed that AANPs were able to improve T cell stimulation compared to free antibodies by increasing IFN-γ excretion (2x). We further confirmed co-localization of antibodies with AANPs on tumor infiltration T cells in vivo. Our data demonstrated that spatial-temporal delivery of agonist and antagonist could improve T cell activation and cancer immunotherapy.

Conclusions: Our data demonstrates that spatial-temporal delivery of agonist and antagonist can improve T cell activation and cancer immunotherapy.

Citation Format: Yu Mi, Christof C. Smith, Feifei Yang, Jonathan Serody, Benjamin Vincent, Andrew Z. Wang. Spatial-temporal delivery of OX40 agonist and PD-1 inhibitor using nanoparticles improves therapeutic efficacy of cancer immunotherapy [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 978. doi:10.1158/1538-7445.AM2017-978

Abstract 1654: Development of subtype specific mouse models of bladder cancer

Introduction: High-grade, muscle-invasive bladder cancer has recently been shown to harbor intrinsic molecular subtypes with distinct biologic features. Current murine models of bladder cancer, including the prominent carcinogen induced model MB49, do not account for subtype specific characteristics, leaving a gap in available tools for understanding subtype specific differences in bladder cancer. We have developed and validated immunocompetent, subtype specific models of bladder cancer, and we have used these models to assess differential responses to immune checkpoint inhibition.

Methods: Two distinct models of murine bladder cancer were developed in a C57BL/6 background. The UPPL models were generated through Pten/Trp53 conditional knockout in Uroplakin3a expressing cells. BBN models were generated through exposure of wild-type C57BL/6 mice to the carcinogen N-Butyl-N-(4-hydmoxybutyl)nitrosamine and subsequent generation of cell lines from spontaneous tumors. RNAseq was performed on several BBN and UPPL tumors and cell lines, with findings validated with flow cytometry and T/B cell receptor (TCR/BCR) amplicon sequencing of tumor infiltrating lymphocytes (TILs).

Results: BBN and UPPL models reflected characteristics of human basal and luminal bladder cancers, respectively. BBN (basal) models demonstrated higher immune gene signature expression, with concordantly higher numbers of TILs compared to the UPPL (luminal) model (p &lt; 0.0001). Two BBN and two UPPL models were assessed for response to anti-PD-1 therapy in vivo as syngeneic tumors grown in wild type C57BL/6 mice. One of the BBN lines (BBN963) demonstrated robust control of tumor growth in some animals, including multiple complete responses (p = 0.0003), but also tumors that progressed, leading us to characterize BBN963 as a mixed response model. The marked response to PD-1 blockade in BBN963 was associated with significantly higher sharing of TCR CDR3 sequences among TILs compared to sequences of the other tumors (p = 0.003). In addition, analysis of BBN963 tumors by flow cytometry demonstrated naïve and memory T cell phenotypes correlated with increased and decreased tumor sizes, respectively. Closer examination of individual BBN963 tumor responses to PD-1 blockade revealed distinct responder and non-responder infiltrating immune cell phenotypes. Responders demonstrated a less diverse B cell repertoire (p = 0.0043) with increased BCR CDR3 sequence sharing (p &lt; 0.0001).

Discussion: We have developed two unique classes of murine bladder cancer lines, UPPL and BBN, with gene expression and TIL profiles that closely correlate with human luminal and basal bladder cancers, respectively. The BBN and UPPL subtype specific models can serve as a tool for elucidating bladder cancer responses to immunotherapy. The mixed response of BBN963 tumors to PD-1 blockade should be an asset for assessing pathways mediating response to checkpoint blockade as well as the value of combination therapy. [C.S., R.S, B.V, W.K contributed equally to this work]

Citation Format: Christof C. Smith, Ryoichi Saito, Lisa M. Bixby, Takanobu Utsumi, Jordan Kardos, Shengjie Chai, Sara E. Wobker, Bhavani Krishnan, Jeffrey S. Damrauer, Jonathan S. Serody, David Darr, Benjamin G. Vincent, William Y. Kim. Development of subtype specific mouse models of bladder cancer [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 1654. doi:10.1158/1538-7445.AM2017-1654

Molecular and clinical characterization of a claudin (CLDN)-low subtype of gastric cancer (GC)

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Background: A CLDN-low subtype has been identified in breast and bladder cancers and is characterized by low expression of tight junction proteins CLDN, enrichment for epithelial-to-mesenchymal transition (EMT) and tumor initiating cell (TIC) features. Given the genomically stable (GS) subtype of GC defined by TCGA has features suggestive of CLDN-low tumors, we evaluated whether the CLDN-low subtype also exists in GC. Methods: 415 tumors from TCGA GC mRNA dataset were clustered on the CLDN, EMT and TIC gene sets with significance testing using SigClust2 to identify CLDN-low GC. A minimal set of genes that could accurately classify CLDN-low GC was defined by prediction analysis of microarrays (PAM). Tumors identified by SigClust2 or the PAM were called CLDN-low GC regardless of the original subtype call. The 300 GCs in the Asian Cancer Research Group (ACRG) dataset [GSE62254] were used to validate the predictor. We characterized clinical and molecular (gene expression, mutation and copy number alteration) features of CLDN-low GC. Results: We identified 46 tumors that had consensus enrichment for CLDN-low features in TCGA. CLDN-low tumors were most commonly diffuse (35/42=83%, 4 tumors=mixed) and GS (36/46=78%). CLDN-low GC showed high expression of immune gene signatures including T and NK cell signatures, but not an immunosuppression signature. Compared to GS subtype, CLDN-low GC had increased frequency of CD44, GATA4, and GATA6 amplification. In ACRG, 28/300 GCs were CLDN-low using the PAM predictor. The CLDN-low GC in ACRG was phenotypically similar to the CLDN-low GC in TCGA based on the CLDN, EMT and TIC gene signatures. Clinically, CLDN-low GC was associated with the shortest overall survival of the 5 subtypes (CLDN-low plus TCGA defined 4 subtypes). Notably, a hazard ratio comparing CLDN-low GC vs GS was 2.10 (95%CI; 1.07-4.11) in TCGA and 2.32 (95%CI; 1.18-4.55) in ACRG cohort, adjusting for age and pathological stage. Conclusions: We identified a CLDN-low GC which has a poor prognosis likely related to the resistance to conventional chemotherapy due to its EMT and TIC-like properties. Further development of targeted therapies against these molecular features is warranted to improve the outcome of CLDN-low GC.

Integrative review on the non-invasive management of lower urinary tract symptoms in men following treatments for pelvic malignancies

AIM

To develop a non-invasive management strategy for men with lower urinary tract symptoms (LUTS) after treatment for pelvic cancer, that is suitable for use in a primary healthcare context.

METHODS

PubMed literature searches of LUTS management in this patient group were carried out, together with obtaining a consensus of management strategies from a panel of authors for the management of LUTS from across the UK.

RESULTS

Data from 41 articles were investigated and collated. Clinical experience was sought from authors where there was no clinical evidence. The findings discussed in this paper confirm that LUTS after the cancer treatment can significantly impair men's quality of life. While many men recover from LUTS spontaneously over time, a significant proportion require long-term management. Despite the prevalence of LUTS, there is a lack of consensus on best management. This article offers a comprehensive treatment algorithm to manage patients with LUTS following pelvic cancer treatment.

CONCLUSION

Based on published research literature and clinical experience, recommendations are proposed for the standardisation of management strategies employed for men with LUTS after the pelvic cancer treatment. In addition to implementing the algorithm, understanding the rationale for the type and timing of LUTS management strategies is crucial for clinicians and patients.

Delayed hematopoietic recovery after auto-SCT in patients receiving arsenic trioxide-based therapy for acute promyelocytic leukemia: a multi-center analysis

A potential link between arsenic (ATO)-based therapy and delayed hematopoietic recovery after autologous hematopoietic SCT (HSCT) for acute promyelocytic leukemia (APL) has previously been reported. We retrospectively reviewed the clinical histories of 58 patients undergoing autologous HSCT for APL at 21 institutions in the United States and Japan. Thirty-three (56%) of the patients received ATO-based therapy prior to stem cell collection. Delayed neutrophil engraftment occurred in 10 patients (17%): 9 of the 10 patients (90%) received prior ATO (representing 27% of all ATO-treated patients), compared with 1 of the 10 patients (10%) not previously treated with ATO (representing 4% of all ATO-naïve patients; P<0.001). Compared with ATO-naïve patients, ATO-treated patients experienced significantly longer times to ANC recovery (median 12 days vs 9 days, P<0.001). In multivariate analysis, the only significant independent predictor of delayed neutrophil engraftment was prior treatment with ATO (hazard ratio 4.87; P<0.001). Of the available stem cell aliquots from APL patients, the median viable post-thaw CD34+ cell recovery was significantly lower than that of cryopreserved autologous stem cell products from patients with non-APL AML. Our findings suggest that ATO exposure prior to CD34+ cell harvest has deleterious effects on hematopoietic recovery after autologous HSCT.

Exenatide dosing in alpacas

In order to investigate whether exenatide could be used to stimulate glucose clearance and insulin secretion in alpacas without causing colic signs, six healthy adult alpacas were injected once a day with increasing subcutaneous doses. A follow-up intravenous glucose injection was given to induce hyperglycemia, and serial blood samples were collected to measure plasma concentrations of glucose, insulin, triglycerides, beta-hydroxybutyrate, and nonesterified fatty acids. The exenatide doses used were saline control (no drug), and 0.02, 0.05, or 0.1 mcg/kg injected subcutaneously. Alpacas had significantly lower plasma glucose concentrations and higher insulin concentrations on all treatment days compared with the control day, but the increase in insulin was significantly greater and lasted significantly longer when the alpacas received the two higher dosages. Two of the alpacas developed mild colic signs at the 0.05 mcg/kg dose and were not evaluated at the highest dose. Based on these findings, the 0.05 mcg/kg dose appears to offer the greatest stimulation of insulin secretion and glucose clearance without excessive risk or severity of complications.

Evolution of sperm quality but not quantity in the internally fertilized fish Xiphophorus nigrensis

Species with alternative reproductive strategies are characterized by discrete differences among males in suites of traits related to competition for fertilizations. Models predict sneaker males should allocate more resources to their ejaculates because they experience sperm competition more frequently and often occupy a disfavoured 'role' owing to subordinance in intramale competition and female preferences for larger males. We examined whether sperm number and quality differed between male strategies in the internally fertilized fish Xiphophorus nigrensis and explored the relationship between sperm morphology and performance. We found sneaker males had similar testes sizes compared to courting males but ejaculates with both more viable and longer lived sperm. Sneaker sperm also had longer midpieces, which was positively correlated with both velocity and longevity. Our study suggests that the evolution of sperm quantity and quality can be decoupled and that the sperm morphology is likely to play an important role in mediating sperm competition through its effects on sperm performance.

The generation of the F2-isoprostane 8-epi-PGF2alpha by human platelets on collagen stimulation

F(2)-isoprostanes are prostaglandin (PG) F(2)-like compounds formed via non-enzymatic peroxidation of arachidonic acid, although some F(2)-isoprostane production may be cyclo-oxygenase (COX)-mediated. Of these substances 8-epi-prostaglandin F(2)alpha (8-epi-PGF(2alpha)) has received the most attention as it induces vasoconstriction and mitogenesis, and influences pathophysiological mechanisms relevant to arterial disease. Using improved methods for F(2)-isoprostane determination we examined collagen-stimulated platelet production of F(2)-isoprostanes in platelet-rich plasma (PRP), distinguishing between the free and esterified forms of these substances. Collagen stimulation caused marked release to the plasma (platelet-poor; PPP) of free 8-epi-PGF(2alpha) (2 +/- 2 pg/mg platelet protein vs 174 +/- 53 pg/mg protein, control (i.e. non-stimulated) vs collagen-stimulated, P < 0.05) and of free 9alpha ,11alpha-PGF (37 +/- 19 pg/mg protein vs 1948 +/- 643 pg/mg protein, control vs stimulated, P < 0.05), a COX derived product. Neither free nor esterified 9alpha, 11beta-PGF and 9beta, 11alpha-PGF(2alpha) were detectable in control or collagen stimulated samples. Sample concentrations of the esters of 8-epi-PGF(2alpha) and 9alpha, 11alpha-PGF(2alpha) were unaltered by collagen stimulation. These data confirm a previous report that activated platelets release the F2-isoprostane 8-epi-PGF(2alpha), accompanying the release of a COX-derived product, 9alpha, 11alpha-PGF(2alpha).

Influence of the alpha-adrenoreceptor naftopidil and doxazosin, on adrenaline-induced serotonin platelets: comparison with the antagonists, collagen and efflux by human effects of nifedipine

Collagen (5 microg/ml) stimulation of washed platelets increased endogenous serotonin (5-HT) release to the medium from 13.88 1.39 to 188.67 26.37 pmol/108 platelets ( P < 0.001). Adrenaline (16 microM) also increased 5-HT release, from 11.0 1.46 to 110.6 29.9 pmol/108 platelets ( P < 0.02). Naftopidil enhanced collagen-induced 5-HT efflux; significant increases occurred with 2 microM (+71.6%, P < 0.01), 10 microM (+89.1%, P < 0.01) and 40 microM (+69.7%, P < 0.01). With 0.4 muM and 2 microM naftopidil, adrenaline-induced 5-HT release was enhanced, albeit non-significantly, whilst with 10 microM and 40 muM naftopidil release was reduced (40 microM,-58.5%, P < 0.05). Doxazosin increased collagen-induced 5-HT release, significant increases being recorded with 7.5 microM (+81.7%, P < 0.05) and 30 microM (+78.4%, P < 0.05). Adrenaline-induced 5-HT release was also increased by doxazosin, but not significantly. Collagen-stimulated 5-HT release was inhibited by nifedipine (7 microM,-38.8%, P < 0.05; 28 microM, -61.2%, P < 0.001). These data suggest that the-antagonists, naftopidil and doxazosin, and the Ca2+ channel blocker, nifedipine, influence agonist-induced platelet 5-HT release through different mechanisms. Thus naftopidil and doxazosin may possess 5-HT transporter-blocking activity. The observation that naftopidil inhibited, adrenaline-induced 5-HT release may indicate that naftopidil also inhibits adrenaline uptake and exchange with dense granular 5-HT, with consequent inhibition of 5-HT release and platelet aggregation. The data obtained with nifedipine are consistent with 5-HT release being reduced as a result of its inhibitory action on platelet Ca2+ mobilisation.

Effects of exenatide on plasma glucose and insulin concentrations in alpacas

BACKGROUND

Exenatide is a degradation-resistant glucagon-like peptide 1 agonist used in the treatment of diabetes mellitus. It enhances the insulin response to hyperglycemia. Because of a poor insulin response, adult camelids are susceptible to hyperglycemia from stress, glucose administration, or energy metabolism disorders. Insulin often is administered to decrease plasma glucose concentration, but this approach has disadvantages such as the risk of hypoglycemia. Noninsulin medications targeting the incretin hormone pathway, such as exenatide, are providing alternate treatment options.

HYPOTHESIS/OBJECTIVES

Exenatide will decrease plasma glucose and increase insulin concentrations in alpacas.

ANIMALS

Six healthy adult alpacas.

METHODS

After food was withheld for 8 hours, alpacas were given, on subsequent days in a randomly determined order, either 0.2 microg/kg of exenatide or similar volume of isotonic saline SC. Blood samples were collected before and 15, 30, 45, 60, 75, 90, 105, and 120 minutes after treatment. A rapid dextrose (0.5 g/kg) injection was given after the time 60 samples. Plasma glucose and insulin concentrations were measured at each time point.

RESULTS

Alpacas had significantly (P=<.001-.015) lower plasma glucose and higher insulin concentrations for the hyperglycemic period after receiving exenatide than after saline injections. Colic signs were observed in 5 of 6 alpacas treated with exenatide.

CONCLUSIONS AND CLINICAL IMPORTANCE

Exenatide appeared to increase insulin release and decrease plasma glucose concentrations in hyperglycemic alpacas. These findings are similar to findings in humans and could support therapeutic usage of exenatide in alpacas. However, induction of colic may limit practical application.

Performance and use of a ribonucleotide reductase herpes simplex virus type-specific serological assay

In response to the increasingly evident need for herpes simplex virus (HSV) serotype-specific serologic assays that rely on proteins other than glycoprotein-G (gG), we developed a rapid serologic assay that is based on type-specific epitopes within the large subunit of HSV ribonucleotide reductase (R1). The assay (Au-2 enzyme-linked immunosorbent assay [ELISA]) uses an HSV type 2 (HSV-2) R1 peptide antigen. It provides a reliable method for detecting serotype-specific antibody to a protein other than gG-2. The Au-2 ELISA has high sensitivity and specificity as determined by direct comparison to Western blotting, a widely accepted "gold standard," and to ELISA with an HSV-1 R1 peptide (Au-1). The use of the Au-2 ELISA in conjunction with the gG-2-based assays will improve the sensitivity and specificity of serologic diagnosis and patient management.

Increasing incidence of acute hepatitis B virus infection referrals to the Aberdeen Infection Unit: a matter for concern

OBJECTIVES

To assess the epidemiology and clinical outcomes of acute hepatitis B virus (HBV) infections presenting to a regional Infection Unit over a ten year period--with reference to the issues of injection drug use and strategies aimed at reducing transmission, notably needle exchange and immunisation programmes.

METHODS

A retrospective casenote review of all patients with acute HBV managed at the Infection Unit in Aberdeen between 1991-2000.

RESULTS

One hundred and nineteen (119) patients with acute HBV infection were managed during the period of review. The annual number of patients increased from a mean of 3.3/year during the years 1991-96 to 46 in 2000. The risk factors associated with HBV infection were being an injection drug user (IDU) in 57 (47.9%), heterosexual sex in 22 (18.5%), sex with an IDU in 4 (3.4%), men who had sex with men in 10 (8.4%), tattooing in 1 (0.8%), a needle stick injury in 1 (0.8%), trauma 1 (0.8%) and unknown in 23 (19.3%). Many of these patients had "dabbled" in drug use. Thirty-one (54.4%) of the IDU patients had previously been hospitalised with drug-related medical problems. Eighteen (31.6%) of the IDUs were receiving methadone at the time of presentation.

CONCLUSIONS

There is an epidemic of HBV infection in the Grampian region of Scotland currently. Forty-six (65.7%) of the 70 infected patients diagnosed during 2000 were seen at the Infection Unit. The remainder had mild or asymptomatic disease and were managed in the community. This epidemic has occurred despite extensive use of local needle exchange facilities and might reflect missed opportunities to immunise IDUs against HBV infection. A co-ordinated approach is now in place to immunise IDUs and other high-risk groups, but the use of universal immunisation demands consideration.

Measures of oxidative stress in heterozygous familial hypercholesterolaemia

Familial hypercholesterolaemia (FH) may be associated with increased oxidative stress which may contribute to atherogenesis. Plasma lipid hydroperoxides (ROOHs), 8-epi PGF(2alpha) and alpha-tocopherol were measured in normal subjects and in newly referred heterozygous FH patients and used as indices of oxidative stress. ROOH levels were higher (+16%), albeit non-significantly, in FH patients than in controls subjects (4.4+/-0.3 vs. 3.8+/-0.3 micromol/l; n=51 and 40, respectively). 8-epi PGF(2alpha) levels were significantly greater (+56%) in the FH patients than in controls (0.43+/-0.06 vs. 0.27+/-0.05 nmol/l; P<0.05; n=14 and 16, respectively). FH patients with vascular disease had significantly higher (+32%) levels of ROOH compared with patients without vascular disease (4.9+/-0.40 vs. 3.7+/-0.33 micromol/l; P<0.05; n=27 and 24, respectively). Similarly, 8-epi PGF(2alpha) concentrations were higher (+100%) in the FH patients with vascular disease than in those without it (0.6+/-0.08 vs. 0.3+/-0.10 nmol/l; P<0.05; n=6 and 8, respectively). Absolute alpha-tocopherol levels in FH patients were similar to those in controls (21.0+/-0.70 vs. 23.8+/-1.30 micromol/l). When alpha-tocopherol levels were expressed relative to cholesterol, however, the concentrations were found to be significantly lower (-43%) in FH patients than in controls (2.9+/-0.10 vs. 5.1+/-0.40 micromol/mmol, P<0.0005). There were no differences in absolute or cholesterol standardised alpha-tocopherol levels in patients with and without vascular disease. These data suggest that oxidative stress is increased in FH-patients and is particularly pronounced in those patients with vascular disease. It is possible that increased oxidative stress may precede the development of vascular disease.

Expression analysis and chromosome location of a novel gene (H11) associated with the growth of human melanoma cells

We have previously described the isolation of a new human gene, H11, that codes for a 25 kDa phosphoprotein with autokinase activity the expression of which is required for cell growth. The data described in this report extend these findings. Using FISH and M-FISH we show that H11 which maps at chromosome site 12q24.1-12q24.31 is not involved in chromosomal translocations. The tissue distribution of H11 mRNA is restricted, with expression being most abundant in skeletal muscle, heart, prostate and placenta. The H11 protein is cytoplasmic and it is associated with the plasma membrane. Cell surface localization in particulate aggregate formations suggests that it may be complexed to proteins involved in the transfer of extracellular growth signals.

Platelet secretion of beta-amyloid is increased in hypercholesterolaemia

Tissue accumulation of the cytotoxic beta-amyloid peptide (Abeta) occurs in Alzheimer's disease (AD), one possible source being the platelet. AD and cardiovascular disease may share some risk factors, including hypercholesterolaemia which is associated with increased platelet activity. We examined platelet Abeta release under resting and collagen-stimulated conditions in normocholesterolaemic and hypercholesterolaemic individuals. Resting platelet Abeta efflux was greater in hypercholesterolaemics than in normocholesterolaemics. Collagen-stimulated Abeta release was concentration-dependent and increased in hypercholesterolaemics. Resting Abeta release correlated positively with plasma total cholesterol and low-density lipoprotein (LDL) cholesterol, and inversely with platelet count. These data indicate that abnormal platelet Abeta release occurs in hypercholesterolaemia.

A growth and latency compromised herpes simplex virus type 2 mutant (ICP10DeltaPK) has prophylactic and therapeutic protective activity in guinea pigs

A growth compromised herpes simplex virus type 2 (HSV-2) mutant which is deleted in the PK domain of the large subunit of ribonucleotide reductase (ICP10DeltaPK) protects from fatal HSV-2 challenge in the mouse model (Aurelian L, Kokuba H, Smith CC. Vaccine potential of a Herpes Simplex Virus type 2 mutant deleted in the PK domain of the large subunit of ribonucleotide reductase (ICP10). Vaccine 1999;17:1951-1963). Here we report the results of our studies with ICP10DeltaPK in the guinea pig model of recurrent HSV-2 disease. ICP10DeltaPK was also compromised for growth and disease causation in this model. It was not isolated from latently infected ganglia by explant co-cultivation. The proportions of latently infected ganglia were significantly lower for ICP10DeltaPK than HSV-2 [3/25 (12%) and 7/10 (70%), respectively]. Similar results were obtained for the levels of viral DNA (8 x 10(3) and 2 x 10(5) molecules/ganglion for ICP10DeltaPK and HSV-2, respectively]. ICP10DeltaPK immunization caused a significant (P< or = 0.001) decrease in the proportion of animals with primary [1/14 (6%) and 16/16 (100%) for ICP10DeltaPK and PBS, respectively) and recurrent [1/14 (6%) and 11/14 (79%) for ICP10DeltaPK and PBS, respectively) HSV-2 skin lesions. It also protected from genital HSV-2 disease [1/10 and 10/10 for ICP10DeltaPK and PBS, respectively] and decreased the severity of the lesions in both models. Quantitative PCR (Q-PCR) with primers that distinguish between HSV-2 and ICP10DeltaPK indicated that immunization reduced the proportion of ganglia positive for HSV-2 DNA [8/25 (32%) and 7/10 (70%) for ICP10DeltaPK and PBS, respectively) and its levels [3 x 10(3) and 2 x 10(5) molecules/ganglion for ICP10DeltaPK and PBS, respectively]. The proportion of HSV-2 infected animals with recurrent disease was also significantly (P < or = 0.001) decreased by immunization with ICP10DeltaPK [1/15 (7%) and 11/14 (79%) with recurrent disease for ICP10DeltaPK and PBS, respectively], suggesting that ICP10DeltaPK has prophylactic and therapeutic activity in the guinea pig.

A novel gene expressed in human keratinocytes with long-term in vitro growth potential is required for cell growth

The herpes simplex virus large subunit of ribonucleotide reductase differs from its counterparts in eukaryotic and prokaryotic cells and in other viruses in that it contains a unique domain that codes for a distinct serine-threonine protein kinase that activates the Ras/MEK/MAPK mitogenic pathway and is required for virus growth. Previous studies suggested that ribonucleotide reductase protein kinase was co-opted from a cellular gene. Cellular genes similar to ribonucleotide reductase protein kinase were not cloned, however, and their function is unknown. Here we report that a novel gene (H11) that codes for a protein similar to herpes simplex virus 2 ribonucleotide reductase protein kinase, is expressed in skin tissues, cultured keratinocytes, and the keratinocyte cell line A431. The protein is phosphorylated and it associates with the plasma membrane. H11 is expressed in keratinocytes with long-term in vitro growth potential and is coexpressed with high levels of adhesion molecules involved in signal transduction, such as beta1 integrin. Antisense oligonucleotides that inhibit H11 expression inhibit DNA synthesis and keratinocyte proliferation, suggesting that H11 expression is required for cell growth.

Ras-GAP binding and phosphorylation by herpes simplex virus type 2 RR1 PK (ICP10) and activation of the Ras/MEK/MAPK mitogenic pathway are required for timely onset of virus growth

We used a herpes simplex virus type 2 (HSV-2) mutant with a deletion in the RR1 (ICP10) PK domain (ICP10DeltaPK) and an MEK inhibitor (PD98059) to examine the role of ICP10 PK in virus growth. In HSV-2-infected cells, ICP10 PK binds and phosphorylates the GTPase activating protein Ras-GAP. In vitro binding and peptide competition assays indicated that Ras-GAP N-SH2 and PH domains, respectively, bind ICP10 at phosphothreonines 117 and 141 and a WD40-like motif at positions 160 to 173. Binding and phosphorylation did not occur in cells infected with ICP10DeltaPK. GTPase activity was significantly lower in HSV-2- than in ICP10DeltaPK-infected cells. Conversely, the levels of activated Ras and mitogen-activated protein kinase (MAPK), and the expression and stabilization of the transcription factor c-Fos were significantly increased in cells infected with HSV-2 or a revertant virus [HSV-2(R)] but not with ICP10DeltaPK. PD98059 inhibited MAPK activation and induction-stabilization of c-Fos. Expression from the ICP10 promoter was increased in cells infected with HSV-2 but not with ICP10DeltaPK, and increased expression was ablated by PD98059. ICP10 DNA formed a complex with nuclear extracts from HSV-2-infected cells which was supershifted by c-Fos antibody and was not seen with extracts from ICP10DeltaPK-infected cells. Complex formation was abrogated by PD98059. Onset of HSV-2 replication was significantly delayed by PD98059 (14 h versus 2 h in untreated cells), a delay similar to that seen for ICP10DeltaPK. The data indicate that Ras-GAP phosphorylation by ICP10 PK is involved in the activation of the Ras/MEK/MAPK mitogenic pathway and c-Fos induction and stabilization. This results in increased ICP10 expression and the timely onset of HSV-2 growth.