Activation of targetable inflammatory immune signaling is seen in myelodysplastic syndromes with SF3B1 mutations

Background

Mutations in the SF3B1 splicing factor are commonly seen in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML), yet the specific oncogenic pathways activated by mis-splicing have not been fully elucidated. Inflammatory immune pathways have been shown to play roles in the pathogenesis of MDS, though the exact mechanisms of their activation in splicing mutant cases are not well understood.

Methods

RNA-seq data from SF3B1 mutant samples was analyzed and functional roles of interleukin-1 receptor-associated kinase 4 (IRAK4) isoforms were determined. Efficacy of IRAK4 inhibition was evaluated in preclinical models of MDS/AML.

Results

RNA-seq splicing analysis of SF3B1 mutant MDS samples revealed retention of full-length exon 6 of IRAK4, a critical downstream mediator that links the Myddosome to inflammatory NF-kB activation. Exon 6 retention leads to a longer isoform, encoding a protein (IRAK4-long) that contains the entire death domain and kinase domain, leading to maximal activation of NF-kB. Cells with wild-type SF3B1 contain smaller IRAK4 isoforms that are targeted for proteasomal degradation. Expression of IRAK4-long in SF3B1 mutant cells induces TRAF6 activation leading to K63-linked ubiquitination of CDK2, associated with a block in hematopoietic differentiation. Inhibition of IRAK4 with CA-4948, leads to reduction in NF-kB activation, inflammatory cytokine production, enhanced myeloid differentiation in vitro and reduced leukemic growth in xenograft models.

Conclusions

SF3B1 mutation leads to expression of a therapeutically targetable, longer, oncogenic IRAK4 isoform in AML/MDS models.

Funding

This work was supported by Cincinnati Children's Hospital Research Foundation, Leukemia Lymphoma Society, and National Institute of Health (R35HL135787, RO1HL111103, RO1DK102759, RO1HL114582), Gabrielle's Angel Foundation for Cancer Research, and Edward P. Evans Foundation grants to DTS. AV is supported by Edward P. Evans Foundation, National Institute of Health (R01HL150832, R01HL139487, R01CA275007), Leukemia and Lymphoma Society, Curis and a gift from the Jane and Myles P. Dempsey family. AP and JB are supported by Blood Cancer UK (grants 13042 and 19004). GC is supported by a training grant from NYSTEM. We acknowledge support of this research from The Einstein Training Program in Stem Cell Research from the Empire State Stem Cell Fund through New York State Department of Health Contract C34874GG. MS is supported by a National Institute of Health Research Training and Career Development Grant (F31HL132420).

Blocking UBE2N abrogates oncogenic immune signaling in acute myeloid leukemia

Dysregulation of innate immune signaling pathways is implicated in various hematologic malignancies. However, these pathways have not been systematically examined in acute myeloid leukemia (AML). We report that AML hematopoietic stem and progenitor cells (HSPCs) exhibit a high frequency of dysregulated innate immune-related and inflammatory pathways, referred to as oncogenic immune signaling states. Through gene expression analyses and functional studies in human AML cell lines and patient-derived samples, we found that the ubiquitin-conjugating enzyme UBE2N is required for leukemic cell function in vitro and in vivo by maintaining oncogenic immune signaling states. It is known that the enzyme function of UBE2N can be inhibited by interfering with thioester formation between ubiquitin and the active site. We performed in silico structure-based and cellular-based screens and identified two related small-molecule inhibitors UC-764864/65 that targeted UBE2N at its active site. Using these small-molecule inhibitors as chemical probes, we further revealed the therapeutic efficacy of interfering with UBE2N function. This resulted in the blocking of ubiquitination of innate immune- and inflammatory-related substrates in human AML cell lines. Inhibition of UBE2N function disrupted oncogenic immune signaling by promoting cell death of leukemic HSPCs while sparing normal HSPCs in vitro. Moreover, baseline oncogenic immune signaling states in leukemic cells derived from discrete subsets of patients with AML exhibited a selective dependency on UBE2N function in vitro and in vivo. Our study reveals that interfering with UBE2N abrogates leukemic HSPC function and underscores the dependency of AML cells on UBE2N-dependent oncogenic immune signaling states.

Eliminating Cervical Cancer: Progress and Challenges for High-income Countries

In 2020, the World Health Organization launched a major initiative to eliminate cervical cancer globally. The initiative is built around the three key pillars of human papillomavirus (HPV) vaccination, cervical screening and treatment, with associated intervention targets for the year 2030. The '90-70-90' targets specify that 90% of adolescent girls receive prophylactic HPV vaccination, 70% of adult women receive a minimum twice-in-a-lifetime cervical HPV test and 90% receive appropriate treatment for preinvasive or invasive disease. Modelling has shown that if these targets are met, the elimination of cervical cancer, defined as fewer than four cases per 100 000 women per annum, will be achieved within a century. Many high-income countries are well positioned to eliminate cervical cancer within the coming decades, but few have achieved '90-70-90' and many challenges must still be addressed to deliver these critical interventions effectively. This review considers the current status of cervical cancer control in relation to each of the three elimination pillars in high-income countries and discusses some of the developments that will assist countries in reaching these ambitious targets by 2030.

Retinal ganglion cell loss and gliosis in the retinofugal projection following intravitreal exposure to amyloid-beta

Pathological accumulations of amyloid-beta (Aβ) peptide are found in retina early in Alzheimer's disease, yet its effects on retinal neuronal structure remain unknown. To investigate this, we injected fibrillized Aβ1-42 protein into the eye of adult C57BL/6 J mice and analyzed the retina, optic nerve (ON), and the superior colliculus (SC), the primary retinal target in mice. We found that retinal Aβ exposure stimulated microglial activation and retinal ganglion cell (RGC) loss as early as 1-week post-injection. Pathology was not limited to the retina, but propagated into other areas of the central nervous system. Microgliosis spread throughout the retinal projection (retina, ON, and SC), with multiplex protein quantitation demonstrating an increase in endogenously produced Aβ in the ON and SC corresponding to the injected retinas. Surprisingly, this pathology spread to the opposite side, with unilateral Aβ eye injections driving increased Aβ levels, neuroinflammation, and RGC death in the opposite, un-injected retinal projection. As Aβ-mediated microglial activation has been shown to propagate Aβ pathology, we also investigated the role of the Aβ-binding microglial scavenger receptor CD36 in this pathology. Transgenic mice lacking the CD36 receptor were resistant to Aβ-induced inflammation and RGC death up to 2 weeks following exposure. These results indicate that Aβ pathology drives regional neuropathology in the retina and does not remain isolated to the affected eye, but spreads throughout the nervous system. Further, CD36 may serve as a promising target to prevent Aβ-mediated inflammatory damage.

TNFAIP3 Plays a Role in Aging of the Hematopoietic System

Hematopoietic stem and progenitor cells (HSPC) experience a functional decline in response to chronic inflammation or aging. Haploinsufficiency of A20, or TNFAIP3, an innate immune regulator, is associated with a variety of autoimmune, inflammatory, and hematologic malignancies. Based on a prior analysis of epigenomic and transcriptomic changes during normal human aging, we find that the expression of A20 is significantly reduced in aged HSPC as compared to young HSPC. Here, we show that the partial reduction of A20 expression in young HSPC results in characteristic features of aging. Specifically, heterozygous deletion of A20 in hematopoietic cells resulted in expansion of the HSPC pool, reduced HSPC fitness, and myeloid-biased hematopoiesis. These findings suggest that altered expression of A20 in HSPC contributes to an aging-like phenotype, and that there may be a common underlying mechanism for diminished HSPC function between inflammatory states and aging.

Adaptive response to inflammation contributes to sustained myelopoiesis and confers a competitive advantage in myelodysplastic syndrome HSCs

Despite evidence of chronic inflammation in myelodysplastic syndrome (MDS) and cell-intrinsic dysregulation of Toll-like receptor (TLR) signaling in MDS hematopoietic stem and progenitor cells (HSPCs), the mechanisms responsible for the competitive advantage of MDS HSPCs in an inflammatory milieu over normal HSPCs remain poorly defined. Here, we found that chronic inflammation was a determinant for the competitive advantage of MDS HSPCs and for disease progression. The cell-intrinsic response of MDS HSPCs, which involves signaling through the noncanonical NF-κB pathway, protected these cells from chronic inflammation as compared to normal HSPCs. In response to inflammation, MDS HSPCs switched from canonical to noncanonical NF-κB signaling, a process that was dependent on TLR-TRAF6-mediated activation of A20. The competitive advantage of TLR-TRAF6-primed HSPCs could be restored by deletion of A20 or inhibition of the noncanonical NF-κB pathway. These findings uncover the mechanistic basis for the clonal dominance of MDS HSPCs and indicate that interfering with noncanonical NF-κB signaling could prevent MDS progression.

Trabecula: A Random Generator of Computational Phantoms for Bone Marrow Dosimetry

This study was motivated by the efforts to evaluate radiation risk for leukemia incidence in the Techa River cohort, where the main bone marrow dose contributors were Sr (bone-seeking beta emitters). Energy deposition in bone marrow targets was evaluated by simulating radiation particle transport using computational phantoms. The present paper describes the computer program Trabecula implementing an algorithm for parametric generation of computational phantoms, which serve as the basis for calculating bone marrow doses. Trabecula is a user-friendly tool that automatically converts analytical models into voxelized representations that are directly compatible as input to Monte Carlo N Particle code.

Enhancements in the Techa River Dosimetry System: TRDS-2016D Code for Reconstruction of Deterministic Estimates of Dose From Environmental Exposures

Waterborne releases to the Techa River from the Mayak plutonium facility in Russia during 1949-1956 resulted in significant doses to persons living downstream. The dosimetry system Techa River Dosimetry System-2016D has been developed, which provides individual doses of external and internal exposure for the members of the Techa River cohort and other persons who were exposed to releases of radioactive material to the Southern Urals. The results of computation of individual doses absorbed in red bone marrow and extraskeletal tissues for the Techa River cohort members (29,647 persons) are presented, which are based on residence histories on the contaminated Techa River and the East Urals Radioactive Trace, which was formed in 1957 as a result of the Kyshtym Accident. Available Sr body-burden measurements and available information on individual household locations have been used for refinement of individual dose estimates. Techa River Dosimetry System-2016D-based dose estimates will be used for verification of risk of low-dose-rate effects of ionizing radiation in the Techa River cohort.

Natural killer cell expression of Ki67 is associated with elevated serum IL-15, disease activity and nephritis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder whose pathology involves multiple immune cell types, including B and T lymphocytes as well as myeloid cells. While it is clear that autoantibody-producing B cells, as well as CD4⁺ T cell help, are key contributors to disease, little is known regarding the role of innate lymphoid cells such as natural killer (NK) cells in the pathogenesis of SLE. We have characterized the phenotype of NK cells by multi-color flow cytometry in a large cohort of SLE patients. While the overall percentage of NK cells was similar or slightly decreased compared to healthy controls, a subset of patients displayed a high frequency of NK cells expressing the proliferation marker, Ki67, which was not found in healthy donors. Although expression of Ki67 on NK cells correlated with Ki67 on other immune cell subsets, the frequency of Ki67 on NK cells was considerably higher. Increased frequencies of Ki67⁺ NK cells correlated strongly with clinical severity and active nephritis and was also related to low NK cell numbers, but not overall leukopenia. Proteomic and functional data indicate that the cytokine interleukin-15 promotes the induction of Ki67 on NK cells. These results suggest a role for NK cells in regulating the immune-mediated pathology of SLE as well as reveal a possible target for therapeutic intervention.

Overcoming the dichotomy of implementing societal flood risk management while conserving instream fish habitat - A long-term study from a highly modified urban river

Flood Risk Management (FRM) is often essential to reduce the risk of flooding to properties and infrastructure in urban landscapes, but typically degrades the habitats required by many aquatic animals for foraging, refuge and reproduction. This conflict between flood risk management and biodiversity is driven by conflicting directives, such as the EU Floods and Water Framework Directives, and has led to a requirement for synergistic solutions for FRM that integrate river restoration actions. Unfortunately, ecological monitoring and appraisal of combined FRM and river restoration works is inadequate. This paper uses a case study from the River Don in Northern England to evaluate the effects of the FRM and subsequent river restoration works on instream habitat and the associated fish assemblage over an 8-year period. Flood risk management created a homogeneous channel but did not negatively affect fish species composition or densities, specifically brown trout. Densities of adult brown trout were comparable pre and post-FRM, while densities of juvenile bullhead and brown trout increased dramatically post FRM. River restoration works created a heterogeneous channel but did not significantly improve species composition or brown trout density. Species composition post-river restoration works returned to that similar to pre-FRM over a short-term period, but with improved numbers of juvenile bullhead. Although habitat complexity increased after river restoration works, long-term changes in species composition and densities were marginal, probably because the river reset habitat complexity within the time framework of the study.

Nodes of Ranvier in Glaucoma

Retinal ganglion cell axons of the DBA/2J mouse model of glaucoma, a model characterized by extensive neuroinflammation, preserve synaptic contacts with their subcortical targets for a time after onset of anterograde axonal transport deficits, axon terminal hypertrophy, and cytoskeletal alterations. Though retrograde axonal transport is still evident in these axons, it is unknown if they retain their ability to transmit visual information to the brain. Using a combination of in vivo multiunit electrophysiology, neuronal tract tracing, multichannel immunofluorescence, and transmission electron microscopy, we report that eye-brain signaling deficits precede transport loss and axonal degeneration in the DBA/2J retinal projection. These deficits are accompanied by node of Ranvier pathology - consisting of increased node length and redistribution of the voltage-gated sodium channel Na_v1.6 that parallel changes seen early in multiple sclerosis (MS) axonopathy. Further, with age, axon caliber and neurofilament density increase without corresponding changes in myelin thickness. In contrast to these findings in DBA/2J mice, node pathologies were not observed in the induced microbead occlusion model of glaucoma - a model that lacks pre-existing inflammation. After one week of systemic treatment with fingolimod, an immunosuppressant therapy for relapsing-remitting MS, DBA/2J mice showed a substantial reduction in node pathology and mild effects on axon morphology. These data suggest that neurophysiological deficits in the DBA/2J may be due to defects in intact axons and targeting node pathology may be a promising intervention for some types of glaucoma.

Autologous Blood Transfusion in Elective Orthopaedic Surgery

Autologous blood transfusion is one of the most effective ways of avoiding the need for homologous transfusion and all its associated complications. Since the beginning of 1985, autotransfusions have been used in 48 patients undergoing total joint replacement, without significant complications. Their average haemoglobin level two weeks postoperatively was 11.3 mg/dl. We believe that this is a safe, effective and economical procedure which benefits both patients and medical staff, and its use should be more widespread.

Enhanced Phosphorylation of Bax and Its Translocation into Mitochondria in the Brains of Individuals Affiliated with Alzheimer's Disease

Background:

Despite increased neuronal death, senile plaques, and neurofibrillary tangles observed in patients suffering from Alzheimer’s disease (AD), the detailed mechanism of cell death in AD is still poorly understood.

Method:

We hypothesized that p38 kinase activates and then phosphorylates Bax, leading to its translocation to mitochondria in AD brains compared to controls. The aim of this study was to investigate the role of p38 kinase in phosphorylation and sub-cellular localization of pro-apoptotic Bax in the frontal cortex of the brains from AD and control subjects. Increased oxidative stress in AD individuals compared to control was evaluated by measuring the levels of carbonylated proteins and oxidized peroxiredoxin, an antioxidant enzyme. The relative amounts of p38 kinase and phospho-Bax in mitochondria in AD brains and controls were determined by immunoblot analysis using the respective antibody against each protein following immunoprecipitation.

Results:

Our results showed that the levels of oxidized peroxiredoxin-SO₃ and carbonylated proteins are significantly elevated in AD brains compared to controls, demonstrating the increased oxidative stress.

Conclusion:

The amount of phospho-p38 kinase is increased in AD brains and the activated p38 kinase appears to phosphorylate Thr residue(s) of Bax, which leads to its mitochondrial translocation, contributing to apoptosis and ultimately, neurodegeneration.

Monkey prefrontal neurons during Sternberg task performance: full contents of working memory or most recent item?

To explore the brain mechanisms underlying multi-item working memory, we monitored the activity of neurons in the dorsolateral prefrontal cortex while macaque monkeys performed spatial and chromatic versions of a Sternberg working-memory task. Each trial required holding three sequentially presented samples in working memory so as to identify a subsequent probe matching one of them. The monkeys were able to recall all three samples at levels well above chance, exhibiting modest load and recency effects. Prefrontal neurons signaled the identity of each sample during the delay period immediately following its presentation. However, as each new sample was presented, the representation of antecedent samples became weak and shifted to an anomalous code. A linear classifier operating on the basis of population activity during the final delay period was able to perform at approximately the level of the monkeys on trials requiring recall of the third sample but showed a falloff in performance on trials requiring recall of the first or second sample much steeper than observed in the monkeys. We conclude that delay-period activity in the prefrontal cortex robustly represented only the most recent item. The monkeys apparently based performance of this classic working-memory task on some storage mechanism in addition to the prefrontal delay-period firing rate. Possibilities include delay-period activity in areas outside the prefrontal cortex and changes within the prefrontal cortex not manifest at the level of the firing rate.NEW & NOTEWORTHY It has long been thought that items held in working memory are encoded by delay-period activity in the dorsolateral prefrontal cortex. Here we describe evidence contrary to that view. In monkeys performing a serial multi-item working memory task, dorsolateral prefrontal neurons encode almost exclusively the identity of the sample presented most recently. Information about earlier samples must be encoded outside the prefrontal cortex or represented within the prefrontal cortex in a cryptic code.

Mapping in-vivo optic nerve head strains caused by intraocular and intracranial pressures

Although it is well documented that abnormal levels of either intraocular (IOP) or intracranial pressure (ICP) can lead to potentially blinding conditions, such as glaucoma and papilledema, little is known about how the pressures actually affect the eye. Even less is known about potential interplay between their effects, namely how the level of one pressure might alter the effects of the other. Our goal was to measure in-vivo the pressure-induced stretch and compression of the lamina cribrosa due to acute changes of IOP and ICP. The lamina cribrosa is a structure within the optic nerve head, in the back of the eye. It is important because it is in the lamina cribrosa that the pressure-induced deformations are believed to initiate damage to neural tissues leading to blindness. An eye of a rhesus macaque monkey was imaged in-vivo with optical coherence tomography while IOP and ICP were controlled through cannulas in the anterior chamber and lateral ventricle, respectively. The image volumes were analyzed with a newly developed digital image correlation technique. The effects of both pressures were highly localized, nonlinear and non-monotonic, with strong interactions. Pressure variations from the baseline normal levels caused substantial stretch and compression of the neural tissues in the posterior pole, sometimes exceeding 20%. Chronic exposure to such high levels of biomechanical insult would likely lead to neural tissue damage and loss of vision. Our results demonstrate the power of digital image correlation technique based on non-invasive imaging technologies to help understand how pressures induce biomechanical insults and lead to vision problems.

Correlation between Cerebral Hemodynamic and Perfusion Pressure Changes in Non-Human Primates

The mechanism that maintains a stable blood flow in the brain despite changes in cerebral perfusion pressure (CPP), and therefore guaranties a constant supply of oxygen and nutrients to the neurons, is known as cerebral autoregulation (CA). In a certain range of CPP, blood flow is mediated by a vasomotor adjustment in vascular resistance through dilation of blood vessels. CA is known to be impaired in diseases like traumatic brain injury, Parkinson's disease, stroke, hydrocephalus and others. If CA is impaired, blood flow and pressure changes are coupled and the oxygen supply might be unstable. Lassen's blood flow autoregulation curve describes this mechanism, where a plateau of stable blood flow in a specific range of CPP corresponds to intact autoregulation. Knowing the limits of this plateau and maintaining CPP within these limits can improve patient outcome. Since CPP is influenced by both intracranial pressure and arterial blood pressure, long term changes in either can lead to autoregulation impairment. Non-invasive methods for monitoring blood flow autoregulation are therefore needed. We propose to use Near infrared spectroscopy (NIRS) to fill this need. NIRS is an optical technique, which measures microvascular changes in cerebral hemoglobin concentration. We pe erformed experiments on non-human primates during exsanguination to demonstrate that the limits of blood flow autoregulation can be accessed with NIRS.

Multidimensional Model of Racial Identity: A Reconceptualization of African American Racial Identity

Research on African American racial identity has utilized 2 distinct approaches. The mainstream approach has focused on universal properties associated with ethnic and racial identities. In contrast, the underground approach has focused on documenting the qualitative meaning of being African American, with an emphasis on the unique cultural and historical experiences of African Americans. The Multidimensional Model of Racial Identity (MMRI) represents a synthesis of the strengths of these two approaches. The underlying assumptions associated with the model are explored. The model proposes 4 dimensions of African American racial identity: salience, centrality, regard, and ideology. A description of these dimensions is provided along with a discussion of how they interact to influence behavior at the level of the event. We argue that the MMRI has the potential to make contributions to traditional research objectives of both approaches, as well as to provide the impetus to explore new questions.

The combined effects of grain supplementation and tenderstretching on alpaca (Vicugna pacos) meat quality

This study investigated the effects of feeding a mixed grain supplement and tenderstretching (TS) alpaca carcasses on meat quality. A total of 56 castrated 24month old alpacas were divided into two treatments (pasture-only, and pasture plus supplementation). Supplemented groups were fed a mixed grain ration in addition to ad lib pasture for 10weeks. Animals were slaughtered across two kill days (n=28). One half of each carcass was suspended by the pelvis (TS) prior to chilling, and the other half was Achilles tendon hung (AH). After 24h, muscles were removed and aged for 10 and 25d. TS significantly increased sarcomere length and reduced shear force and cooking loss in the m. semimembranosus. This trend was not observed in other muscles including the m. longissimus thoracis et lumborum (LL) and m. psoas major. Ageing period resulted in a marginal improvement in LL tenderness. There is clear evidence that TS improves tenderness in the hindquarter of alpacas.

A review of new agents evaluated against pediatric acute lymphoblastic leukemia by the Pediatric Preclinical Testing Program

Acute lymphoblastic leukemia (ALL) in children exemplifies how multi-agent chemotherapy has improved the outcome for patients. Refinements in treatment protocols and improvements in supportive care for this most common pediatric malignancy have led to a cure rate that now approaches 90%. However, certain pediatric ALL subgroups remain relatively intractable to treatment and many patients who relapse face a similarly dismal outcome. Moreover, survivors of pediatric ALL suffer the long-term sequelae of their intensive treatment throughout their lives. Therefore, the development of drugs to treat relapsed/refractory pediatric ALL, as well as those that more specifically target leukemia cells, remains a high priority. As pediatric malignancies represent a minority of the overall cancer burden, it is not surprising that they are generally underrepresented in drug development efforts. The identification of novel therapies relies largely on the reappropriation of drugs developed for adult malignancies. However, despite the large number of experimental agents available, clinical evaluation of novel drugs for pediatric ALL is hindered by limited patient numbers and the availability of effective established drugs. The Pediatric Preclinical Testing Program (PPTP) was established in 2005 to provide a mechanism by which novel therapeutics could be evaluated against xenograft and cell line models of the most common childhood malignancies, including ALL, to prioritize those with the greatest activity for clinical evaluation. In this article, we review the results of >50 novel agents and combinations tested against the PPTP ALL xenografts, highlighting comparisons between PPTP results and clinical data where possible.

Xenograft assessment of predictive biomarkers for standard head and neck cancer therapies

Head and neck squamous cell carcinoma (HNSCC) remains a challenging cancer to treat with overall 5-year survival on the order of 50–60%. Therefore, predictive biomarkers for this disease would be valuable to provide more effective and individualized therapeutic approaches for these patients. While prognostic biomarkers such as p16 expression correlate with outcome; to date, no predictive biomarkers have been clinically validated for HNSCC. We generated xenografts in immunocompromised mice from six established HNSCC cell lines and evaluated response to cisplatin, cetuximab, and radiation. Tissue microarrays were constructed from pre- and posttreatment tumor samples derived from each xenograft experiment. Quantitative immunohistochemistry was performed using a semiautomated imaging and analysis platform to determine the relative expression of five potential predictive biomarkers: epidermal growth factor receptor (EGFR), phospho-EGFR, phospho-Akt, phospho-ERK, and excision repair cross-complementation group 1 (ERCC1). Biomarker levels were compared between xenografts that were sensitive versus resistant to a specific therapy utilizing a two-sample t-test with equal standard deviations. Indeed the xenografts displayed heterogeneous responses to each treatment, and we linked a number of baseline biomarker levels to response. This included low ERCC1 being associated with cisplatin sensitivity, low phospho-Akt correlated with cetuximab sensitivity, and high total EGFR was related to radiation resistance. Overall, we developed a systematic approach to identifying predictive biomarkers and demonstrated several connections between biomarker levels and treatment response. Despite these promising initial results, this work requires additional preclinical validation, likely involving the use of patient-derived xenografts, prior to moving into the clinical realm for confirmation among patients with HNSCC.

Abstract 4243: EGFR inhibition causes growth delay and induces apoptosis in HPV-positive head and neck cancer

Purpose: Cetuximab, a monoclonal antibody inhibiting the epidermal growth factor receptor (EGFR), is approved for use in the treatment of head and neck cancer (HNC).  However, studies of cetuximab were performed with HPV-negative cells, clinical trials were performed without regard to HPV status, and current studies on HPV+ HNC treatment with cetuximab are contradicting. This study was performed to determine whether HPV+ HNC responds to cetuximab and to examine the mechanisms through which cetuximab affects HPV+ HNC. 

Methods: Four HPV+ cell lines were assessed for EGFR expression by immunoblot. Sensitivity to cetuximab was tested by examining cell proliferation and colony formation. Apoptosis was measured by caspase activation, flow cytometry for Annexin V, and immunoblot. Cell cycle was assessed by immunoblot and flow cytometry for propidium iodide stained cells.  HPV+ HNC subcutaneous flank cell line xenografts and patient-derived xenografts were placed in immunocompromised mice treated with cetuximab, tumor size was measured twice weekly.

Results: Cetuximab treatment resulted in significant delay in cell proliferation and significant decrease in colony formation. Cetuximab caused an increase in apoptosis in all methods measured. Also, as previously seen in HPV- cell lines, cetuximab resulted in a G1 cell cycle arrest. Using both cell line and patient-derived xenograft models of HPV+ HNCs, cetuximab resulted in significant tumor growth delay (median time to tumor quadrupling: 15 vs. 24 days, and 42 vs. 89 days, respectively).

Conclusions: Epidermal growth factor receptor inhibition by cetuximab is effective in slowing proliferation and inducing apoptosis in HPV+ HNC. The proposed mechanism of action appears to be similar to that shown in HPV- HNC. These results suggest that cetuximab may play a role in the management of patients with HPV+ HNC.

Citation Format: Alexandra D. Torres Law, Grace C. Blitzer, Molly A. Smith, Eric A. Armstrong, Randall J. Kimple. EGFR inhibition causes growth delay and induces apoptosis in HPV-positive head and neck cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4243. doi:10.1158/1538-7445.AM2014-4243

Bivalirudin for the treatment of patients with confirmed or suspected heparin-induced thrombocytopenia

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is an adverse immune-mediated response to unfractionated heparin and, less commonly, low molecular weight heparin. It is associated with a high thrombotic risk and the potential for limb and life-threatening complications. Argatroban is the only approved and currently available anticoagulant for HIT treatment in the USA.

OBJECTIVES

To report safety and efficacy outcomes with bivalirudin for HIT treatment.

METHODS

We retrospectively examined records from our registry of patients with a suspected, confirmed or previous history of HIT and who had received bivalirudin for anticoagulation in a single tertiary-care center over a 9-year period.

RESULTS

We identified 461 patients who received bivalirudin: 220 (47.7%) were surgical patients, and 241 (52.3%) were medical patients. Of this population, 107 (23.2%) were critically ill, and 109 (23.6%) were dialysis-dependent. Suspected, confirmed and previous history of HIT were reported in 262, 124 and 75 patients, respectively. Of 386 patients with suspected or confirmed HIT, 223 patients (57.8%) had thrombosis at HIT diagnosis. New thrombosis was identified in 21 patients (4.6%) while they were on treatment with therapeutic doses of bivalirudin. No patient required HIT-related amputation. Major bleeding occurred in 35 patients (7.6%). We found a significant increase in major bleeding risk in the critically ill population (13.1%; odds ratio 2.4, 95% confidence interval 1.2-4.9, P = 0.014). The 30-day all-cause mortality rate was 14.5% (67 patients), and eight of 67 (1.7%) deaths were HIT-related.

CONCLUSION

Bivalirudin may be an effective and safe alternative option for the treatment of both suspected and confirmed HIT, and appears to reduce the rate of HIT-related amputation.

LIM proteins in actin cytoskeleton mechanoresponse

The actin cytoskeleton assembles into branched networks or bundles to generate mechanical force for critical cellular processes such as establishment of polarity, adhesion, and migration. Stress fibers (SFs) are contractile actomyosin structures that physically couple to the extracellular matrix through integrin-based focal adhesions (FAs), thereby transmitting force into and across the cell. Recently, LIN-11, Isl1, and MEC-3 (LIM) domain proteins have been implicated in mediating this cytoskeletal mechanotransduction. Among the more well-studied LIM domain adapter proteins is zyxin, a dynamic component of both FAs and SFs. Here we discuss recent research detailing the mechanisms by which SFs adjust their structure and composition to balance mechanical forces and suggest ways that zyxin and other LIM domain proteins mediate mechanoresponse.

High-power beam transport through a hollow-core photonic bandgap fiber

We investigate the use of a seven-cell hollow-core photonic bandgap fiber for transport of CW laser radiation from a single-mode, narrow-linewidth, high-power fiber laser amplifier. Over 90% of the amplifier output was coupled successfully and transmitted through the fiber in a near-Gaussian mode, with negligible backreflection into the source. 100 W of power was successfully transmitted continuously without damage and 160 W of power was transmitted briefly before the onset of thermal lensing in the coupling optics.

Review of the clinical and biologic aspects of human papillomavirus-positive squamous cell carcinomas of the head and neck

Human papillomavirus (HPV), a known etiology of a subset of head-and-neck squamous cell carcinomas (HNCs), causes numerous alterations in normal cellular functions. This article reviews the biology, detection, and treatment of HPV-positive HNC. The role of HPV oncoproteins in tumor development, the natural history of HPV infection, and risk factors for and prevention of transmission of oral HPV are considered. Commonly used methods for detecting HPV infection, including limitations of these methods, are discussed to aid the practicing clinician in using these tests in their clinical practice. Clinical characteristics of HPV-positive HNC, including potential explanations for the improved outcomes seen in patients with HPV-positive HNC, are assessed. Ongoing clinical trials specific for patients with HPV-positive HNC are described, and areas in need of additional research are summarized. Until the results of ongoing trials are known, treatment of HPV-positive HNC should not differ in clinical practice from treatment of similar non-HPV related cancers.

Colon Cancer Staging in Vulnerable Older Adults: Adherence to National Guidelines and Impact on Survival

BACKGROUND

There is concern that elders are not adequately evaluated prior to colon cancer surgery. We sought to determine adherence with ACOVE-3 (Assessing Care of Vulnerable Elders) quality indicators for pre-operative staging prior to colectomy for colon cancer utilizing the Surveillance, Epidemiology and End Results (SEER)-Medicare linked database (1992-2005).

METHODS

We determined the proportion of patients aged 75 and older who had preoperative staging prior to colectomy for colon adenocarcinoma. Preoperative staging was defined as abdominopelvic computed tomography or magnetic resonance imaging scan (SCAN) and colonoscopy or flexible sigmoidoscopy (SCOPE). Multivariate logistic regression identified predictors of adherence. Odds ratios were adjusted for comorbidity, socioeconomic status, and disease severity. The association of adherence to ACOVE-3 and survival was quantified.

RESULTS

Of the 37,862 patients, the majority were 75-84 years, 28% of the patients were ≥85 years. Regarding preoperative staging in the 6-month interval prior to surgical resection, 8% had neither SCAN nor SCOPE, 6% had only SCAN, 43% had only SCOPE, and 43% had both SCAN and SCOPE. Compared to patients who were not staged, those evaluated with either SCOPE alone or SCAN plus SCOPE had lower odds of 3-year mortality. Patients who were staged with SCAN alone had an increased odds of death compared to those who had neither SCAN or SCOPE.

CONCLUSIONS

These data demonstrate that the majority of vulnerable elders with colon cancer did not receive appropriate preoperative staging prior to resection. The findings also confirm that adherence to ACOVE-3 guidelines is associated with improved long-term survival.

Functional analysis of serially expanded human iPS cell-derived RPE cultures

PURPOSE

To determine the effects of serial expansion on the cellular, molecular, and functional properties of human iPS cell (hiPSC)-derived RPE cultures.

METHODS

Fibroblasts obtained from four individuals were reprogrammed into hiPSCs and differentiated to RPE cells using previously described methods. Patches of deeply pigmented hiPSC-RPE were dissected, dissociated, and grown in culture until they re-formed pigmented monolayers. Subsequent passages were obtained by repeated dissociation, expansion, and maturation of RPE into pigmented monolayers. Gene and protein expression profiles and morphological and functional characteristics of hiPSC-RPE at different passages were compared with each other and to human fetal RPE (hfRPE).

RESULTS

RPE from all four hiPSC lines could be expanded more than 1000-fold when serially passaged as pigmented monolayer cultures. Importantly, expansion of hiPSC-RPE monolayers over the first three passages (P1-P3) resulted in decreased expression of pluripotency and neuroretinal markers and maintenance of characteristic morphological features and gene and protein expression profiles. Furthermore, P1 to P3 hiPSC-RPE monolayers reliably demonstrated functional tight junctions, G-protein-coupled receptor-mediated calcium transients, phagocytosis and degradation of photoreceptor outer segments, and polarized secretion of biomolecules. In contrast, P4 hiPSC-RPE cells failed to form monolayers and possessed altered morphological and functional characteristics and gene expression levels.

CONCLUSIONS

Highly differentiated, pigmented hiPSC-RPE monolayers can undergo limited serial expansion while retaining key cytological and functional attributes. However, passaging hiPSC-RPE cultures beyond senescence leads to loss of such features. Our findings support limited, controlled passaging of patient-specific hiPSC-RPE to procure cells needed for in vitro disease modeling, drug screening, and cellular transplantation.

Synergistic activities of a silver(I) glutamic acid complex and reactive oxygen species (ROS): a novel antimicrobial and chemotherapeutic agent

The antimicrobial and chemotherapeutic activities of a silver(I) glutamic acid complex with the synergistic concomitant generation of reactive oxygen species (ROS) were investigated here. The ROS generation system employed was via Fenton chemistry. The antimicrobial and chemotherapeutic activities were investigated on Staphylococcus aureus ATCC 43300 and Escherichia coli bacteria, and Vero and MCF-7 tumor cell lines, respectively. Antimicrobial activities were conducted by determining minimum inhibitory concentration (MIC), while chemotherapeutic efficacies were done by serial dilution using standard techniques to determine the half maximal inhibitory concentration (IC50). The antimicrobial and chemotherapeutic results obtained were compared with positive control drugs gentamicin, oxacillin, penicillin, streptomycin and cisplatin, a ubiquitously used platinum-based antitumor drug, and with the silver(I) glutamic acid complex and hydrogen peroxide separately. Based on MIC and IC50 values, it was determined that this synergistic approach was very effective at extremely low concentrations, especially when compared with the other drugs evaluated here. This finding might be of great significance regarding metronomic dosing when this synergistic approach is clinically implemented. Since silver at low concentrations exhibits no toxic, mutagenic and carcinogenic activities, this might offer an alternative approach for the development of safer silver-based antimicrobial and chemotherapeutic drugs, thereby reducing or even eliminating the toxicity associated with current drugs. Accordingly, the present approach might be integrated into the systemic clinical treatment of infectious diseases and cancer.

Mechanism of allopurinol induced TPMT inhibition

Up to 1/5 of patients with wildtype thiopurine-S-methyltransferase (TPMT) activity prescribed azathioprine (AZA) or mercaptopurine (MP) demonstrate a skewed drug metabolism in which MP is preferentially methylated to yield methylmercaptopurine (MeMP). This is known as thiopurine hypermethylation and is associated with drug toxicity and treatment non-response. Co-prescription of allopurinol with low dose AZA/MP (25-33%) circumvents this phenotype and leads to a dramatic reduction in methylated metabolites; however, the biochemical mechanism remains unclear. Using intact and lysate red cell models we propose a novel pathway of allopurinol mediated TPMT inhibition, through the production of thioxanthine (TX, 2-hydroxymercaptopurine). In red blood cells pre-incubated with 250 μM MP for 2h prior to the addition of 250 μM TX or an equivalent volume of Earle's balanced salt solution, there was a significant reduction in the concentration of MeMP detected at 4h and 6h in cells exposed to TX (4 h, 1.68, p=0.0005, t-test). TX acts as a direct TPMT inhibitor with an apparent Ki of 0.329 mM. In addition we have confirmed that the mechanism is relevant to in vivo metabolism by demonstrating raised urinary TX levels in patients receiving combination therapy. We conclude that the formation of TX in patients receiving combination therapy with AZA/MP and allopurinol, likely explains the significant reduction of methylated metabolites due to direct TPMT inhibition.

Enhanced radiation sensitivity in HPV-positive head and neck cancer

Patients with human papillomavirus (HPV+)-associated head and neck cancer (HNC) show significantly improved survival outcome compared with those with HPV-negative (HPV-) tumors. Published data examining this difference offers conflicting results to date. We systematically investigated the radiation sensitivity of all available validated HPV+ HNC cell lines and a series of HPV- HNC cell lines using in vitro and in vivo techniques. HPV+ HNCs exhibited greater intrinsic radiation sensitivity (average SF2 HPV-: 0.59 vs. HPV+: 0.22; P < 0.0001), corresponding with a prolonged G2-M cell-cycle arrest and increased apoptosis following radiation exposure (percent change 0% vs. 85%; P = 0.002). A genome-wide microarray was used to compare gene expression 24 hours following radiation between HPV+ and HPV- cell lines. Multiple genes in TP53 pathway were upregulated in HPV+ cells (Z score 4.90), including a 4.6-fold increase in TP53 (P < 0.0001). Using immortalized human tonsillar epithelial (HTE) cells, increased radiation sensitivity was seen in cell expressing HPV-16 E6 despite the effect of E6 to degrade p53. This suggested that low levels of normally functioning p53 in HPV+ HNC cells could be activated by radiation, leading to cell death. Consistent with this, more complete knockdown of TP53 by siRNA resulted in radiation resistance. These results provide clear evidence, and a supporting mechanism, for increased radiation sensitivity in HPV+ HNC relative to HPV- HNC. This issue is under active investigation in a series of clinical trials attempting to de-escalate radiation (and chemotherapy) in selected patients with HPV+ HNC in light of their favorable overall survival outcome.

Neurofilaments are the major neuronal target of hydroxynonenal-mediated protein cross-links

Lipid peroxidation generates reactive aldehydes, most notably hydroxynonenal (HNE), which covalently binds amino acid residue side chains leading to protein inactivation and insolubility. Specific adducts of lipid peroxidation have been demonstrated to be intimately associated with pathological lesions of Alzheimer's disease (AD), suggesting that oxidative stress is a major component in the disease. Here, we examined the HNE-cross-linking modifications by using an antibody specific for a lysine-lysine cross-link. Since in a prior study we noted no immunolabeling of neuritic plaques or neurofibrillary tangles but instead found strong labeling of axons, we focused this study on axons. Axonal labeling was examined in mouse sciatic nerve, and immunoblotting showed the cross-link was restricted to neurofilament heavy and medium subunits, which while altering migration, did not indicate larger NF aggregates, indicative of intermolecular cross-links. Examination of mice at various ages showed the extent of modification remaining relatively constant through the life span. These findings demonstrate lipid-cross-linking peroxidation primarily involves lysine-rich neurofilaments and is restricted to intramolecular cross-links.

Abstract 5474: Epidermal growth factor inhibition of HPV positive head and neck cancer cells and primary tumorgrafts results in significant growth inhibition mediated by apoptosis

Purpose: Cetuximab, a monoclonal antibody targeting the epidermal growth factor receptor (EGFR), is approved for use in the treatment of head and neck cancer (HNC). One recent study (SPECTRUM) suggested that patient with recurrent or metastatic HPV+ HNC do not benefit from treatment with EGFR targeted therapy. However, most studies of EGFR inhibition have been performed with HPV-negative cells and clinical trials have been performed without regard to HPV status. We performed this study to determine whether HPV+ HNC cells and patient-derived tumorgrafts respond to cetuximab and to examine the mechanisms through which cetuximab affects HPV+ HNC.

Methods: Four HPV+ cell lines (UD-SCC2, UM-SCC47, UPCI-SCC90, 93-VU-147T) were assessed for EGFR expression by western blot. Sensitivity to cetuximab was tested by assessing cell density 2, 4, 6, and 8 days after cetuximab treatment and by assessing colony formation 2 weeks after plating. Apoptosis was measured by caspase activation, flow cytometry for Annexin V and propidium iodide staining, and immunoblot. Cell cycle was assessed by immunoblot for cyclin D1, cyclin B1, and p27Kip-1 and confirmed by flow cytometry for propidium iodide stained cells. Subcutaneous flank xenografts and tumorgrafts were performed in Hsd:athymic Nude-Foxn1nu female mice treated with intraperitoneal cetuximab (0.2mg/mouse) delivered twice weekly for 2 weeks. Time to tumor quadrupling from baseline was assessed by Kaplan-Meier method.

Results: Significant variation in EGFR expression was seen in HPV+ cells. Cetuximab treatment resulted in significant delay in cell proliferation (p&lt;0.005 for all lines) and decrease in colony formation (p&lt;0.04 for all lines). In these cell lines, cetuximab caused an increase in apoptosis as measured by caspase activity, Bax activation, and Annexin V labeling. In addition, as previously seen in HPV- cell lines, cetuximab increased p27Kip-1 and decreased cyclin B1 and cyclin D1 coinciding with in a G1 cell cycle arrest. Using both a cell line xenograft model and a direct-from-patient tumorgraft model of HPV+ HNCs, cetuximab resulted in significant tumor growth delay (median time to tumor quadrupling: 15 vs. 24 days, p=0.02; and 42 vs. 89 days, p=0.0001, respectively).

Conclusions: Epidermal growth factor receptor inhibition by cetuximab appears to be effective in slowing proliferation and inducing apoptosis in HPV+ HNC. The proposed mechanism of action appears to be similar to that shown over a decade ago in HPV- HNC. These results suggest that cetuximab may play a role in the management of patients with HPV+ HNC.

Citation Format: Grace C. Blitzer, Molly A. Smith, Alexandra D. Torres, Eric A. Armstrong, Paul M. Harari, Paul F. Lambert, Randall J. Kimple. Epidermal growth factor inhibition of HPV positive head and neck cancer cells and primary tumorgrafts results in significant growth inhibition mediated by apoptosis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5474. doi:10.1158/1538-7445.AM2013-5474

Abstract 73: Preclinical evaluation of chemoradiation with cetuximab HPV-positive head and neck cancer suggests significant radiosensitization

PURPOSE: Whether cetuximab, a monoclonal antibody to the epidermal growth factor receptor, should be combined with radiation in patients with human papillomavirus (HPV) positive locally advanced head and neck cancer (HNC) is not known. Currently available data are inadequate to address this important therapeutic question. We sought to examine the ability of cetuximab to act as a radiosensitizer and to examine the mechanism of action of this combination in a model system of HPV+ HNC.

METHODS: Four cell lines (UD-SCC2, UM-SCC47, UPCI-SCC90, 93-VU-147T) validated for HPV expression were used for all assays. Subcutaneous flank xenografts were performed in Hsd:athymic Nude-Foxn1nu female mice treated with intraperitoneal cetuximab (0.2mg/mouse) or flank radiation (2 Gy/fraction) delivered twice weekly for 2 weeks. Time to tumor quadrupling from baseline was assessed by Kaplan-Meier method. Flow cytometry was used to assess apoptosis by Annexin V staining and cell cycle distribution by propidium iodide staining.

RESULTS: While there was minimal in vitro radiosensitization after treatment with cetuximab (similar to that seen in HPV-negative HNC), cetuximab + radiation resulted in a significant increase in time to tumor quadrupling compared to cetuximab alone (p=0.001) or radiation alone (p&lt;0.0001) in HPV+ HNC xenografts. Increased apoptosis was seen in cetuximab and radiation treated cells. Analysis of cell cycle distribution 24 hours after drug treatment showed that cetuximab induced a modest G1 cell cycle arrest when given prior to radiation, but that 24 hours after combined therapy, a significant G2 arrest was present.

CONCLUSIONS: Using HPV+ HNC cell lines, radiation and cetuximab appear to be beneficial compared to either treatment alone. This combination, currently undergoing study in randomized clinical trial is being further evaluated in a direct from patient tumorgraft model of HPV+ HNC to further understand predictors of response.

Citation Format: Molly A. Smith, Grace C. Blitzer, Alexandra D. Torres, Eric A. Armstrong, Paul F. Lambert, Paul M. Harari, Randall J. Kimple. Preclinical evaluation of chemoradiation with cetuximab HPV-positive head and neck cancer suggests significant radiosensitization. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 73. doi:10.1158/1538-7445.AM2013-73

B vitamins and cognitive performance in older adults: review

A copious amount of scientific scrutiny has been dedicated to documenting typical and atypical human ageing, with a substantial body of work focusing upon the impact of lifestyle choices. One such lifestyle choice is that of diet and, in particular, micronutrient ingestion. Epidemiological studies have reported positive associations between B vitamin status and cognitive function, including negative associations between biological markers (i.e., homocysteine) of dysregulated one-carbon metabolism and cognitive function. This has led to a surge of randomised control trials (RCTs) investigations into B vitamin therapy. However, results have continuingly failed to show beneficial behavioural effects. Despite this, results reliably show treatment-related increases in B vitamin level and decreases in homocysteine level—both of which have been identified as risk factors for atypical ageing. In this paper we argue that it would be premature to conclude that B vitamin therapy has no potential and that more research is needed to systematically investigate the optimal dose, the therapeutic “window,” and individual differences in therapy responders and nonresponders. We start with a brief look at one-carbon metabolism and then consider the evidence from epidemiological studies and RCTs in relation to three specific B vitamins: folic acid (B9), pyridoxine (B6), and cobamides (B12).

Two methods for modelling the propagation of terahertz radiation in a layered structure

Modelling the interaction of terahertz(THz) radiation with biological tissueposes many interesting problems. THzradiation is neither obviously described byan electric field distribution or anensemble of photons and biological tissueis an inhomogeneous medium with anelectronic permittivity that is bothspatially and frequency dependent making ita complex system to model.A three-layer system of parallel-sidedslabs has been used as the system throughwhich the passage of THz radiation has beensimulated. Two modelling approaches havebeen developed a thin film matrix model anda Monte Carlo model. The source data foreach of these methods, taken at the sametime as the data recorded to experimentallyverify them, was a THz spectrum that hadpassed though air only.Experimental verification of these twomodels was carried out using athree-layered in vitro phantom. Simulatedtransmission spectrum data was compared toexperimental transmission spectrum datafirst to determine and then to compare theaccuracy of the two methods. Goodagreement was found, with typical resultshaving a correlation coefficient of 0.90for the thin film matrix model and 0.78 forthe Monte Carlo model over the full THzspectrum. Further work is underway toimprove the models above 1 THz.

Catalogue of human tissue optical properties at terahertz frequencies

Recently published studies suggest thatterahertz pulsed imaging will have applications inmedicine and biology, but there iscurrently very little information about the opticalproperties of human tissue at terahertzfrequencies. Such information would be useful forpredicting the feasibility of proposedapplications, optimising acquisition protocols,providing information about variability ofhealthy tissue and supplying data for studies of theinteraction mechanisms. Research ethicscommittee approval was obtained, andmeasurements made from samples of freshlyexcised human tissue, using a broadbandterahertz pulsed imaging system comprisingfrequencies approximately 0.5 to 2.5 THz.Refractive index and linear absorptioncoefficient were found. Reproducibility wasdetermined using blood from one volunteer,which was drawn and measured on consecutivedays. Skin, adipose tissue, striatedmuscle, vein and nerve were measured (to date, from oneindividual). Water had a higher refractiveindex (2.04 ± 0.07) than any tissue.The linear absorption coefficient was higher formuscle than adipose tissue, as expectedfrom the higher hydration of muscle. As these samples camefrom a single subject, there is currentlyinsufficient statistical power to draw firmconclusions, but results suggest that in vivo clinical imaging will be feasible in certainapplications.

The mu/kappa agonist nalbuphine attenuates sensitization to the behavioral effects of cocaine

Sensitization refers to an increase in sensitivity to a drug and is believed to play a role in the etiology of substance use disorders. The purpose of the present study was to evaluate the ability of the mixed mu/kappa agonist nalbuphine to modulate sensitization to the locomotor and positive reinforcing effects of cocaine. Rats were habituated to a locomotor activity chamber and treated with saline (1.0 ml/kg, ip), cocaine (10 mg/kg, ip), or cocaine+nalbuphine (10 mg/kg, ip) every day for 10 days. Following locomotor activity testing, rats were implanted with intravenous catheters and cocaine self-administration was examined on fixed ratio (FR) and progressive ratio (PR) schedules of reinforcement. Rats treated with cocaine exhibited a progressive increase in locomotor activity over the 10-day treatment period, and this effect was significantly reduced in rats treated with cocaine+nalbuphine. In self-administration tests, rats treated with cocaine exhibited significantly higher levels of responding at a threshold dose of cocaine (0.03 mg/kg/infusion) on both FR and PR schedules than rats treated with saline. This increase in responding at a threshold dose of cocaine was blocked completely in rats treated with cocaine+nalbuphine. These data suggest that nalbuphine attenuates the development of sensitization to the behavioral effects of cocaine.

Development and characterization of HPV-positive and HPV-negative head and neck squamous cell carcinoma tumorgrafts

PURPOSE

To develop a clinically relevant model system to study head and neck squamous cell carcinoma (HNSCC), we have established and characterized a direct-from-patient tumorgraft model of human papillomavirus (HPV)-positive and HPV-negative cancers.

EXPERIMENTAL DESIGN

Patients with newly diagnosed or recurrent HNSCC were consented for donation of tumor specimens. Surgically obtained tissue was implanted subcutaneously into immunodeficient mice. During subsequent passages, both formalin-fixed/paraffin-embedded as well as flash-frozen tissues were harvested. Tumors were analyzed for a variety of relevant tumor markers. Tumor growth rates and response to radiation, cisplatin, or cetuximab were assessed and early passage cell strains were developed for rapid testing of drug sensitivity.

RESULTS

Tumorgrafts have been established in 22 of 26 patients to date. Significant diversity in tumorgraft tumor differentiation was observed with good agreement in degree of differentiation between patient tumor and tumorgraft (Kappa 0.72). Six tumorgrafts were HPV-positive on the basis of p16 staining. A strong inverse correlation between tumorgraft p16 and p53 or Rb was identified (Spearman correlations P = 0.085 and P = 0.002, respectively). Significant growth inhibition of representative tumorgrafts was shown with cisplatin, cetuximab, or radiation treatment delivered over a two-week period. Early passage cell strains showed high consistency in response to cancer therapy between tumorgraft and cell strain.

CONCLUSIONS

We have established a robust human tumorgraft model system for investigating HPV-positive and HPV-negative HNSCC. These tumorgrafts show strong correlation with the original tumor specimens and provide a powerful resource for investigating mechanisms of therapeutic response as well as preclinical testing.

iPS cell modeling of Best disease: insights into the pathophysiology of an inherited macular degeneration

Best disease (BD) is an inherited degenerative disease of the human macula that results in progressive and irreversible central vision loss. It is caused by mutations in the retinal pigment epithelium (RPE) gene BESTROPHIN1 (BEST1), which, through mechanism(s) that remain unclear, lead to the accumulation of subretinal fluid and autofluorescent waste products from shed photoreceptor outer segments (POSs). We employed human iPS cell (hiPSC) technology to generate RPE from BD patients and unaffected siblings in order to examine the cellular and molecular processes underlying this disease. Consistent with the clinical phenotype of BD, RPE from mutant hiPSCs displayed disrupted fluid flux and increased accrual of autofluorescent material after long-term POS feeding when compared with hiPSC-RPE from unaffected siblings. On a molecular level, RHODOPSIN degradation after POS feeding was delayed in BD hiPSC-RPE relative to unaffected sibling hiPSC-RPE, directly implicating impaired POS handling in the pathophysiology of the disease. In addition, stimulated calcium responses differed between BD and normal sibling hiPSC-RPE, as did oxidative stress levels after chronic POS feeding. Subcellular localization, fractionation and co-immunoprecipitation experiments in hiPSC-RPE and human prenatal RPE further linked BEST1 to the regulation and release of endoplasmic reticulum calcium stores. Since calcium signaling and oxidative stress are critical regulators of fluid flow and protein degradation, these findings likely contribute to the clinical picture of BD. In a larger context, this report demonstrates the potential to use patient-specific hiPSCs to model and study maculopathies, an important class of blinding disorders in humans.

Cocaine-induced cardiotoxicity in vitro

A growing number of reports have related cocaine use with the onset of myocardial infarction in young otherwise healthy individuals. Although the cardiac effects of cocaine have traditionally been attributed to sympathomimetic stimulation, several studies have suggested that cocaine may be directly cardiotoxic. The purpose of this study was to evaluate the cardiotoxic effects of cocaine in an in vitro preparation devoid of sympathetic innervation. Primary cultures of rat cardiac muscle and non-muscle cells were prepared from hearts excised from 3-5-day-old Sprague-Dawley rats. Cultures were exposed to various cocaine concentrations (1 x 10(-7)-1 x 10(-3)m) for 1-24 hr. Beating activity, morphological status and lactate dehydrogenase (LDH) leakage were evaluated following cocaine exposure. A decrease in the beating activity of cultured muscle cells was observed 1 hr after exposure to the highest cocaine concentrations (1 x 10(-5)-1 x 10(-3)m) tested. Similar results were obtained 24 hr after exposure. Morphological alterations in muscle cells were evident only after exposure to the highest concentration (1 x 10(-3)m). Vacuoles appeared 1 hr after cocaine exposure and were replaced by dark granules within 24 hr. LDH release was significantly elevated in the muscle cell cultures exposed to 1 x 10(-3)m cocaine for 24 hr. The pattern of cocaine-induced morphological alterations and enzyme leakage was similar in non-muscle cells. These data suggest that cocaine induces direct toxic effects on both cardiac muscle and non-muscle cells maintained in an environment free of neuronal and hormonal influences.

Formation of amino acids and nucleotide bases in a Titan atmosphere simulation experiment

The discovery of large (>100 u) molecules in Titan's upper atmosphere has heightened astrobiological interest in this unique satellite. In particular, complex organic aerosols produced in atmospheres containing C, N, O, and H, like that of Titan, could be a source of prebiotic molecules. In this work, aerosols produced in a Titan atmosphere simulation experiment with enhanced CO (N(2)/CH(4)/CO gas mixtures of 96.2%/2.0%/1.8% and 93.2%/5.0%/1.8%) were found to contain 18 molecules with molecular formulae that correspond to biological amino acids and nucleotide bases. Very high-resolution mass spectrometry of isotopically labeled samples confirmed that C(4)H(5)N(3)O, C(4)H(4)N(2)O(2), C(5)H(6)N(2)O(2), C(5)H(5)N(5), and C(6)H(9)N(3)O(2) are produced by chemistry in the simulation chamber. Gas chromatography-mass spectrometry (GC-MS) analyses of the non-isotopic samples confirmed the presence of cytosine (C(4)H(5)N(3)O), uracil (C(5)H(4)N(2)O(2)), thymine (C(5)H(6)N(2)O(2)), guanine (C(5)H(5)N(5)O), glycine (C(2)H(5)NO(2)), and alanine (C(3)H(7)NO(2)). Adenine (C(5)H(5)N(5)) was detected by GC-MS in isotopically labeled samples. The remaining prebiotic molecules were detected in unlabeled samples only and may have been affected by contamination in the chamber. These results demonstrate that prebiotic molecules can be formed by the high-energy chemistry similar to that which occurs in planetary upper atmospheres and therefore identifies a new source of prebiotic material, potentially increasing the range of planets where life could begin.

Preclinical pharmacology of AZD2327: a highly selective agonist of the δ-opioid receptor

In the present article, we summarize the preclinical pharmacology of 4-{(R)-(3-aminophenyl)[4-(4-fluorobenzyl)-piperazin-1-yl]methyl}-N,N-diethylbenzamide (AZD2327), a highly potent and selective agonist of the δ-opioid receptor. AZD2327 binds with sub-nanomolar affinity to the human opioid receptor (K(i) = 0.49 and 0.75 nM at the C27 and F27 isoforms, respectively) and is highly selective (>1000-fold) over the human μ- and κ-opioid receptor subtypes as well as >130 other receptors and channels. In functional assays, AZD2327 shows full agonism at human δ-opioid receptors ([(35)S]GTPγ EC(50) = 24 and 9.2 nM at C27 and F27 isoforms, respectively) and also at the rat and mouse δ-opioid receptors. AZD2327 is active in a wide range of models predictive of anxiolytic activity, including a modified Geller-Seifter conflict test and social interaction test, as well as in antidepressant models, including learned helplessness. In animals implanted with microdialysis probes and then given an acute stressor by pairing electric shock delivery with a flashing light, there is an increase in norepinephrine release into the prefrontal cortex associated with this acute anxiety state. Both the benzodiazepine anxiolytic standard diazepam and AZD2327 blocked this norepinephrine release equally well, and there was no evidence of tolerance to these effects of AZD2327. Overall, these data support the role of the δ-opioid receptor in the regulation of mood, and data suggest that AZD2327 may possess unique antidepressant and anxiolytic activities that could make a novel contribution to the pharmacotherapy of psychiatric disorders.

Formation of NH3 and CH2NH in Titan's upper atmosphere

The large abundance of NH3 in Titan's upper atmosphere is a consequence of coupled ion and neutral chemistry. The density of NH3 is inferred from the measured abundance of NH4+. NH3 is produced primarily through reaction of NH2 with H2CN, a process neglected in previous models. NH2 is produced by several reactions including electron recombination of CH2NH2+. The density of CH2NH2+ is closely linked to the density of CH2NH through proton exchange reactions and recombination. CH2NH is produced by reaction of N(2D) and NH with ambient hydrocarbons. Thus, production of NH3 is the result of a chain of reactions involving non-nitrile functional groups and the large density of NH3 implies large densities for these associated molecules. This suggests that amine and imine functional groups may be incorporated as well in other, more complex organic molecules.