Modification of α-Tocopherol Succinate with a Tumor-targeting Peptide Conjugate Enhances the Antitumor Efficacy of a Paclitaxel-loaded Lipid Aggregate

Paclitaxel (PTX) is a widely used chemotherapeutic agent in the clinic. However, its clinical benefit is limited due to its low water solubility, off-target toxicity, and for being a multidrug-resistant (MDR) substrate. To overcome these limitations in this study, a tumor-targeting peptide (CRGDK peptide, a ligand for NRP-1 receptor) conjugate of α-tocopheryl succinate (α-TOS) was synthesized and modified on PTX-loaded lipid aggregate (TL-PTX) to leverage the benefits of α-TOS, which include a) anti-cancer activity, b) increased PTX loading, and c) inhibition of MDR activity. Use of peptide conjugate of α-TOS (α-TOS-CRGDK) in lipid aggregate increased PTX entrapment efficiency by 20%, helped in NRP-1 specific cellular uptake and significantly enhanced apoptotic and cell killing activity (p <0.01) of PTX compared to control formulation (CL-PTX) by inhibiting MDR-activity in melanoma resulting in ∼70% increment in overall survival of melanoma tumor-bearing mice. In conclusion, CRGDK- α-TOS conjugate in association with PTX-loaded liposome provided a unique NRP-1 targeted, drug-resistant reversing anticancer regimen for treating aggressive melanoma.

Changing Trend in the Etiological Spectrum of Hoarseness of Voice in Rural India: A Prospective Hospital-Based Study

Hoarseness of voice is one of the common symptoms with which patient presents to an otorhinolaryngologist. Hoarseness is a symptom of diverse etiology. The aim of the study was to study the problem of hoarseness relating to its incidence and to identify the common etiologies and predisposing factors leading to hoarseness of voice. This study comprises of 70 cases of hoarseness presenting to Department of Otorhinolaryngology, VIMS, Ballari, Karnataka from October 2015 to March 2017. After taking a thorough history, a complete otolaryngological examination was carried out and supported by relevant investigations, diagnosis was reached. The incidence of hoarseness of voice was noted to be 0.21% in our study. The majority of patients were in 31-40 years and 51-60 years of age group, and male to female ratio was 3.7:1, farmers constituted single largest group (34.3%), and most of the patients were from the rural area (82.9%). Smoking was the commonest habit (54.29%) predisposing to hoarseness of voice. Maximum patients presented with hoarseness of duration of 1-3 months. Laryngeal malignancy was the commonest aetiology noted in our study (38.6%). A complaint of hoarseness may represent a serious disease and, therefore, should not be ignored, especially if present for more than 2 weeks. It needs a complete evaluation to rule out malignancy as a cause.

Stress degradation study of bortezomib: effect of co-solvent, isolation and characterization of degradation products by UHPLC-Q-TOF-MS/MS and NMR and evaluation of the toxicity of the degradation products

Bortezomib (BTZ) is a first-in-class, potent reversible inhibitor of proteasome used in the treatment of multiple myeloma, the second most common hematological cancer.

Amphetamine decorated cationic lipid nanoparticles cross the blood-brain barrier: therapeutic promise for combating glioblastoma

Combating brain tumors (glioblastoma multiforme or GBM) is a formidable challenge because of the existence of blood-brain barrier (BBB), a tight cellular junction that separates the central nervous system (CNS) and systemic circulation. Such a selectively permeable barrier prevents the entry of therapeutic molecules from blood circulation to brain parenchyma. Towards enhancing the efficacy of brain tumor-selective drug delivery without perturbing the BBB integrity, nanometric drug carriers are increasingly becoming an efficient therapeutic modality in preclinical studies. Psychostimulant drugs such as amphetamine and methylated amphetamine (METH) are known to penetrate the BBB. Still, little effort has been made to exploit them in nano-drug delivery, largely due to their toxicities. Herein, for the first time, we design, synthesize, and formulate three different β-amphetaminylated cationic lipid nanoparticles. We show that the β-amphetaminylated cationic lipid nanoparticles are nontoxic and can cross the BBB presumably through active transcytosis. The BBB penetrating ability also depends on the hydrophilic-hydrophobic balance of the lipids, with hexadecyl lipid (16-BACL) nanoparticle showing maximum accumulation in the brain. The lipid nanoparticle of 16-BACL can simultaneously encapsulate paclitaxel and PDL1-siRNA. The dual drug-loaded lipid nanoparticles showed apoptosis driven cellular cytotoxicity against GL261 cells and improved the overall survivability of orthotopic glioblastoma bearing mice compared to their non-targeting counterpart. The present work describes a new class of BBB-crossing lipid nanoparticles and delineates their therapeutic promise against glioblastoma.

Identification and structural characterization of the stress degradation products of omeprazole using Q-TOF-LC-ESI-MS/MS and NMR experiments: evaluation of the toxicity of the degradation products

Omeprazole (OMP), a prototype proton pump inhibitor used for the treatment of peptic ulcers and gastroesophageal reflux disease (GERD), was subjected to forced degradation studies as per ICH guidelines Q1A (R2).

Identification and characterization of stress degradation products of sumatriptan succinate by using LC/Q-TOF-ESI-MS/MS and NMR: Toxicity evaluation of degradation products

Sumatriptan succinate, a selective 5-HT1B receptor agonist, was subjected to forced degradation studies as per to International Conference on Harmonization-specified conditions. The drug exclusively showed its degradation under basic, photolytic, and oxidative stress conditions, whereas it was found to be stable under acidic, thermal, and neutral conditions. Eight (DP-1 to DP-8) degradation products were identified and characterized by UPLC-ESI/MS/MS experiments combined with accurate mass measurements. The effective chromatographic separation was achieved on Hibar Purospher STAR, C18 (250 × 4.6 mm, 5 μm) column using mobile phase consisting of 0.1% formic acid and methanol at a flow rate of 0.6 mL/minute in gradient elution method. It is noteworthy that 2 major degradation products DP-3 and DP-7 were isolated using preparative HPLC and characterized by advanced NMR experiments. The degradation pathway of the sumatriptan was established, which was duly justified by mechanistic explanation. In vitro cytotoxicity of isolated DPs was tested on normal human cells such as HEK 293 (embryonic kidney cells) and RWPE-1 (normal prostate epithelial cells). This study revealed that they were nontoxic up to 100 μm concentration. Further, in silico toxicity of the drug and its degradation products was determined using ProTox-II prediction tool. This study revealed that DP-4 and DP-8 are predicted for immune toxicity. Amine oxidase A and prostaglandin G/H synthase 1 are predicted as toxicity targets for DP-3, DP-4, and DP-6 whereas DP-1 and DP-2 are predicted for amine oxidase A target.

Liquid chromatography/electrospray ionization tandem mass spectrometry study of repaglinide and its forced degradation products

RATIONALE

Stress stability studies of drugs have been recognized as an essential part of the drug development process. These studies are used to investigate the intrinsic stability of the drugs and for the development of a selective stability indicating assay method (SIAM). Stress testing is also useful for the formulation and packaging development, shelf-life determination and designing of manufacturing processes. As per regulatory guidelines, stress degradation studies and structural characterization should be carried out to establish degradation pathways of the drug, which is essential from both the efficacy and safety point of view. As the stress stability studies of repaglinide have not been reported in the literature, the present study has been undertaken.

METHODS

Repaglinide (RP), an oral anti-diabetic drug, was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress conditions as per International Conference on Harmonization (ICH) guidelines Q1A (R2). The chromatographic separation of the drug and its degradation products (DPs) was achieved on an Agilent XDB C-18 column using the gradient elution method with a mobile phase consisting of 20 mM ammonium acetate and acetonitrile at flow rate of 1.0 mL min^-1 . The DPs were characterized using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) in combination with accurate mass measurements.

RESULTS

The drug degraded under hydrolytic and oxidative stress, while it was stable under thermal and photolytic stress conditions. In total, six DPs were formed and the LC/MS method described here can resolve all DPs from the parent as well as from each other under various stress conditions. To elucidate the structures of DPs, fragmentation of the [M + H]⁺ ions of RP and its DPs was studied by using LC/ESI-MS/MS combined with accurate mass measurements.

CONCLUSIONS

The forced degradation of RP carried out as per ICH guidelines results in the formation of six degradation products which have been characterized using LC/MS/MS in combination with accurate mass measurements.

Identification and structural characterization of in vivo metabolites of balofloxacin in rat plasma, urine and feces samples using Q-TOF/LC/ESI/MS/MS : In silico toxicity studies

Balofloxacin is a fluroquinolone antibiotic drug which has been used for the treatment of urinary tract infections (UTIs). Identification and structural characterization of metabolites is a critical component of both drug discovery and drug development research. In vivo metabolites of balofloxacin have been identified and characterized by using liquid chromatography positive ion electrospray ionization high resolution tandem mass spectrometry (LC/ESI-HR-MS/MS) experiments. To identify in vivo metabolites, blood, urine and feces samples were collected after oral administration of the drug to the female Sprague-Dawley rats (n = 3 per group). Protein precipitation, freeze liquid separation followed by solid-phase extraction methods were used for sample preparation. The extracted samples were subjected to LC-ESI/HRMS/MS analysis. The chromatographic separation of the drug and its metabolites were achieved on a XDB, C18 (50, 4.6 mm, 5 mm) column using gradient elution method in combination with 0.1% formic acid and acetonitrile at a flow rate of 0.4 mL/min. A total of 13 phase I and phase II metabolites of balofloxacin have been identified in plasma, urine and feces samples. Most of metabolites were observed in plasma and urine samples including dealkylated, desmethylated, decarbonylated, decarboxylated, hydroxylated, methylated, carboxylated, cysteine conjugated metabolites and high abundance glucuronidated metabolite. The structures of metabolites have been elucidated based on fragmentation patterns, accurate mass measurements and LC/MS/MS experiments. The main phase I metabolites of balofloxacin, decarbonylated, decarboxylated and desmethylated metabolites and phase II methylated metabolite undergo subsequent phase II glucuronidation pathways. In silico toxicity of the drug and its metabolites was determined using ProTox-II. Metabolites B-1, B-2, B-5, B-6, B-7, and B-8 to B-13 were predicted to possess immunotoxicity with high probability score. Additionally, Amine Oxidase A and Prostaglandin G/H Synthase 1 are predicted for metabolites B-1, B-3 to B-6 as toxicity targets with binding probability.

Gastric lipoma: a rare cause of haematemesis

Gastric lipomas are rare benign tumours of the stomach, representing less than 3% of all benign gastric neoplasms. They are usually asymptomatic but larger lesions can present with abdominal pain, gastric outlet obstruction and haematemesis. Malignant transformation is extremely rare. Accurate preoperative diagnosis can be established with computed tomography. Being benign, extensive surgery is not necessary and simple excision of the lesion is adequate. Small asymptomatic lesions can be followed up. We present a case of 80-year-old woman with gastric submucosal lipoma who presented with haematemesis.

Forced degradation studies of lansoprazole using LC-ESI HRMS and 1 H-NMR experiments: in vitro toxicity evaluation of major degradation products

Regulatory agencies from all over the world have set up stringent guidelines with regard to drug degradation products due to their toxic effects or carcinogenicity. Lansoprazole, a proton-pump inhibitor, was subjected to forced degradation studies as per ICH guidelines Q1A (R2). The drug was found to degrade under acidic, basic, neutral hydrolysis and oxidative stress conditions, whereas it was found to be stable under thermal and photolytic conditions. The chromatographic separation of the drug and its degradation products were achieved on a Hiber Purospher, C18 (250 × 4.6 mm, 5 μ) column using 10 mM ammonium acetate and acetonitrile as a mobile phase in a gradient elution mode at a flow rate of 1.0 ml/min. The eight degradation products (DP1-8) were identified and characterized by UPLC/ESI/HRMS with in-source CID experiments combined with accurate mass measurements. DP-1, DP-2 and DP-3 were formed in acidic, DP-4 in basic, DP-5 in neutral and DP-1, DP-6, DP-7 and DP-8 were in oxidation stress condition Among eight degradation products, five were hitherto unknown degradation products. In addition, one of the major degradation products, DP-2, was isolated by using semi preparative HPLC and other two, DP-6 and DP-7 were synthesized. The cytotoxic effect of these degradation products (DP-2, DP-6 and DP-7) were tested on normal human cells such as HEK 293 (embryonic kidney cells) and RWPE-1(normal prostate epithelial cells) by MTT assay. From the results of cytotoxicity, it was found that lansoprazole as well as its degradation products (DP-2, DP-6 and DP-7) were nontoxic up to 50-μM concentrations, and the latter showed slightly higher cytotoxicity when compared with that of lansoprazole. DNA binding studies using spectroscopic techniques indicate that DP-2, DP-6 and DP-7 molecules interact with ctDNA and may bind to its surface. Copyright © 2017 John Wiley & Sons, Ltd.

A stability-indicating LC-MS/MS method for zidovudine: Identification, characterization and toxicity prediction of two major acid degradation products

Zidvovudine (AZT) is a nucleoside analogue reverse transcriptase inhibitor (NRTI), a class of anti-retroviral drug. A stability-indicating assay method for AZT was developed in line with ICH guideline. Successful separation of AZT and its degradation products was achieved by gradient elution mode on reverse phase C₁₈ column using 10 mM ammonium acetate: acetonitrile as the mobile phase at 0.8 mL/min flow rate, 25 µL injection volume, 30 °C column temperature and 285 nm detection wavelength. Two major acid degradation products were identified and characterized by liquid chromatography–electrospray ionization mass spectrometry (LC–ESI/MS/MS) and accurate mass measurements. The probable mechanisms for the formation of degradation products were identified based on a comparison of the fragmentation pattern of the [M + H] ⁺ ions of AZT and its degradation products. One of the degradation products, DP-1, was isolated by semi-preparative high performance liquid chromatography (HPLC) using Waters XBridge Prep C₁₈ (250 mm×10 mm, 5 µm). Degradation products showed higher toxicity compared to the drug in some models assessed by TOPKAT software. The method validation was performed with respect to robustness, specificity, linearity, precision and accuracy as per ICH guideline Q2 (R1).

From the bench to clinical practice: understanding the challenges and uncertainties in immunogenicity testing for biopharmaceuticals

Unlike conventional chemical drugs where immunogenicity typically does not occur, the development of anti-drug antibodies following treatment with biologics has led to concerns about their impact on clinical safety and efficacy. Hence the elucidation of the immunogenicity of biologics is required for drug approval by health regulatory authorities worldwide. Published ADA 'incidence' rates can vary greatly between same-class products and different patient populations. Such differences are due to disparate bioanalytical methods and interpretation approaches, as well as a plethora of product-specific and patient-specific factors that are not fully understood. Therefore, the incidence of ADA and their association with clinical consequences cannot be generalized across products. In this context, the intent of this review article is to discuss the complex nature of ADA and key nuances of the methodologies used for immunogenicity assessments, and to dispel some fallacies and myths.

Identification and characterization of stressed degradation products of rabeprazole using LC-ESI/MS/MS and 1H-NMR experiments: in vitro toxicity evaluation of major degradation products

Rabeprazole, an antiulcer drug in the class of proton pump inhibitors was subjected to force degradation studies as per ICH guidelines Q1A (R2).

Understanding and predicting suicidality using a combined genomic and clinical risk assessment approach

Worldwide, one person dies every 40 seconds by suicide, a potentially preventable tragedy. A limiting step in our ability to intervene is the lack of objective, reliable predictors. We have previously provided proof of principle for the use of blood gene expression biomarkers to predict future hospitalizations due to suicidality, in male bipolar disorder participants. We now generalize the discovery, prioritization, validation, and testing of such markers across major psychiatric disorders (bipolar disorder, major depressive disorder, schizoaffective disorder, and schizophrenia) in male participants, to understand commonalities and differences. We used a powerful within-participant discovery approach to identify genes that change in expression between no suicidal ideation and high suicidal ideation states (n=37 participants out of a cohort of 217 psychiatric participants followed longitudinally). We then used a convergent functional genomics (CFG) approach with existing prior evidence in the field to prioritize the candidate biomarkers identified in the discovery step. Next, we validated the top biomarkers from the prioritization step for relevance to suicidal behavior, in a demographically matched cohort of suicide completers from the coroner's office (n=26). The biomarkers for suicidal ideation only are enriched for genes involved in neuronal connectivity and schizophrenia, the biomarkers also validated for suicidal behavior are enriched for genes involved in neuronal activity and mood. The 76 biomarkers that survived Bonferroni correction after validation for suicidal behavior map to biological pathways involved in immune and inflammatory response, mTOR signaling and growth factor regulation. mTOR signaling is necessary for the effects of the rapid-acting antidepressant agent ketamine, providing a novel biological rationale for its possible use in treating acute suicidality. Similarly, MAOB, a target of antidepressant inhibitors, was one of the increased biomarkers for suicidality. We also identified other potential therapeutic targets or biomarkers for drugs known to mitigate suicidality, such as omega-3 fatty acids, lithium and clozapine. Overall, 14% of the top candidate biomarkers also had evidence for involvement in psychological stress response, and 19% for involvement in programmed cell death/cellular suicide (apoptosis). It may be that in the face of adversity (stress), death mechanisms are turned on at a cellular (apoptosis) and organismal level. Finally, we tested the top increased and decreased biomarkers from the discovery for suicidal ideation (CADM1, CLIP4, DTNA, KIF2C), prioritization with CFG for prior evidence (SAT1, SKA2, SLC4A4), and validation for behavior in suicide completers (IL6, MBP, JUN, KLHDC3) steps in a completely independent test cohort of psychiatric participants for prediction of suicidal ideation (n=108), and in a future follow-up cohort of psychiatric participants (n=157) for prediction of psychiatric hospitalizations due to suicidality. The best individual biomarker across psychiatric diagnoses for predicting suicidal ideation was SLC4A4, with a receiver operating characteristic (ROC) area under the curve (AUC) of 72%. For bipolar disorder in particular, SLC4A4 predicted suicidal ideation with an AUC of 93%, and future hospitalizations with an AUC of 70%. SLC4A4 is involved in brain extracellular space pH regulation. Brain pH has been implicated in the pathophysiology of acute panic attacks. We also describe two new clinical information apps, one for affective state (simplified affective state scale, SASS) and one for suicide risk factors (Convergent Functional Information for Suicide, CFI-S), and how well they predict suicidal ideation across psychiatric diagnoses (AUC of 85% for SASS, AUC of 89% for CFI-S). We hypothesized a priori, based on our previous work, that the integration of the top biomarkers and the clinical information into a universal predictive measure (UP-Suicide) would show broad-spectrum predictive ability across psychiatric diagnoses. Indeed, the UP-Suicide was able to predict suicidal ideation across psychiatric diagnoses with an AUC of 92%. For bipolar disorder, it predicted suicidal ideation with an AUC of 98%, and future hospitalizations with an AUC of 94%. Of note, both types of tests we developed (blood biomarkers and clinical information apps) do not require asking the individual assessed if they have thoughts of suicide, as individuals who are truly suicidal often do not share that information with clinicians. We propose that the widespread use of such risk prediction tests as part of routine or targeted healthcare assessments will lead to early disease interception followed by preventive lifestyle modifications and proactive treatment.

Assessment and reporting of the clinical immunogenicity of therapeutic proteins and peptides-harmonized terminology and tactical recommendations

Immunogenicity is a significant concern for biologic drugs as it can affect both safety and efficacy. To date, the descriptions of product immunogenicity have varied not only due to different degrees of understanding of product immunogenicity at the time of licensing but also due to an evolving lexicon that has generated some confusion in the field. In recent years, there has been growing consensus regarding the data needed to assess product immunogenicity. Harmonization of the strategy for the elucidation of product immunogenicity by drug developers, as well as the use of defined common terminology, can benefit medical practitioners, health regulatory agencies, and ultimately the patients. Clearly, understanding the incidence, kinetics and magnitude of anti-drug antibody (ADA), its neutralizing ability, cross-reactivity with endogenous molecules or other marketed biologic drugs, and related clinical impact may enhance clinical management of patients treated with biologic drugs. To that end, the authors present terms and definitions for describing and analyzing clinical immunogenicity data and suggest approaches to data presentation, emphasizing associations of ADA development with pharmacokinetics, efficacy, and safety that are necessary to assess the clinical relevance of immunogenicity.

Understanding ethics guidelines using an internet-based expert system

National and international guidelines outlining ethical conduct in research involving humans and animals have evolved into large and complex documents making the process of gaining ethics approval a complicated task for researchers in the area. Researchers, in particular those who are relatively new to the ethics approval process, can struggle to understand the parts of an ethics guideline that apply to their research and the nature of their ethical obligations to trial participants. With the scope of medical research likely to continue to expand in the future, it is clear that ethics guidelines will only increase in complexity and number. This paper describes one possible solution to the

PROBLEM

the use of an internet-based expert system to intelligently and interactively distribute the information stored in ethics guidelines to individual researchers. This paper also details how one such system was designed and tested with respect to Australian medical research ethics guidelines.

Rational design, synthesis and evaluation of (6aR∗,11bS∗)-1-(4-fluorophenyl)-4-{7-[4-(4-fluorophenyl)-4-oxobutyl]1,2,3,4,6,6a,7,11b,12,12a(RS)-decahydropyrazino[2′,1′:6,1]pyrido[3,4-b]indol-2-yl}-butan-1-one as a potential neuroleptic agent

In our pursuit to prepare a potent antipsychotic compound, a novel 1,2,3,4,6,6a,7,11b,12,12a-decahydropyrazino[2',1':6,1]pyrido[3,4-b]indole derivative was synthesized which incorporates the butyrophenone substructure twice. This molecule has shown D(1), D(2) and 5-HT(2A) receptor blocking activity where the ratio pK(i) (5-HT(2A)) to pK(i) (D(2)) is 1.42 better than risperidone (1.15). It blocks amphetamine induced hyperactivity/stereotypy and secondary conditioned avoidance responses in rodents at lower doses than those required for the neuroleptic drugs haloperidol and centbutindole (biriperone).

Idiopathic pneumonia syndrome after bone marrow transplantation: the role of pre-transplant radiation conditioning and local cytokine dysregulation in promoting lung inflammation and fibrosis

Pulmonary complications and graft-vs.-host disease (GVHD) remain severe threats to survival after bone marrow transplantation (BMT). Idiopathic pneumonia syndrome (IPS) accounts for nearly 50% of all the cases of interstitial pneumonitis after BMT. IPS is characterized by an early inflammatory phase followed by chronic inflammation and fibrosis of lung tissue; however, the immunopathogenesis of this disease is not yet clearly understood. This biphasic syndrome has been reported to be associated with pre-transplant radiation conditioning in some studies while others have suggested that GVHD or autoimmune phenomena may be responsible for its development. The early post-BMT phase is characterized by the presence of inflammatory cytokines whose net effect is to promote lymphocyte influx into lungs with minimal fibrosis, that leads to an acute form of graft-vs.-host reaction-mediated pulmonary tissue damage. Gradual changes over time in leucocyte influx and activation lead to dysregulated wound repair mechanisms resulting from the shift in the balance of cytokines that promote fibrosis. Using data from new animal models of IPS and information from studies of human IPS, we hypothesize that cytokine-modulated immunological mechanisms which occur during the acute and chronic phases after bone marrow transplantation lead to the development of the progressive, inflammatory, and fibrotic lung disease typical of idiopathic pneumonia syndrome.

American Association for Cancer Research: potential target antigens for cancer immunotherapy. April 1-5, 2000, San Francisco, CA, USA

The 91st annual meeting of the American Association for Cancer Research (AACR) convened this year in San Francisco, USA. Nearly 5600 abstracts were published within ten broad research categories ranging from basic molecular, cellular and pharmaceutical research to cancer epidemiology and prevention. The largest number of poster presentations belonged in the 'Pharmacological and Experimental Therapeutics' section, followed closely by 'Molecular Biology' and 'Cell and Tumour Biology'. Novel tumour antigens and their potential application in cancer immunotherapy were displayed primarily in a section categorised as 'Immunology/Preclinical and Clinical'. This article reports some of the significant tumour antigen-related studies presented at this meeting.

Immune monitoring of cancer patients undergoing experimental immunotherapy

Advancements in the understanding of cellular immunity within the last decade, along with the characterization of tumor antigens, have led to immunotherapeutic approaches for cancer therapy. This mode of treatment is expected to provide more tumor-specific activity, thereby being less toxic to normal cells than standard modalities. Clinical trials are underway throughout the world to determine whether immunotherapy is a practical and viable alternative to conventional cancer therapies. Unlike radiotherapy and chemotherapy, wherein tumor regression is the standard for determining efficacy of the regimens, immunotherapy has to be evaluated by the examination of several immunological parameters within patients. The purpose of this article is to review the methods currently utilized to evaluate the induction, maintenance, and duration of antitumor immune reactivity in cancer patients undergoing immunotherapy.

Bacterial lipopolysaccharide induced B cell activation is mediated via a phosphatidylinositol 3-kinase dependent signaling pathway

Bacterial lipopolysaccharide (LPS) is a potent stimulant of B cells and macrophages. LPS induces B cell proliferation and differentiation into antibody secreting cells. In addition, LPS also stimulates IL-6 secretion in mature B cells and in immature B cell lines such as WEHI-231. Although sufficient literature is available on LPS induced signaling events in monocytes and macrophages, the mechanisms involved in LPS induced B cell activation are not well understood. In this report, it is shown that both LPS mediated B cell proliferation and IL-6 secretion are dependent on phosphatidylinositol 3-kinase (PI 3-kinase) signaling pathways. The B cell specific co-receptor, CD19 is not tyrosine phosphorylated in LPS stimulated B cells. Thus, in contrast to B cell antigen receptor (BCR) signaling, the activation of PI 3-kinase appears not to be related to the recruitment of PI 3-kinase to tyrosine phosphorylated CD19. This is the first demonstration of the importance of PI 3-kinase signaling pathway in LPS mediated B lymphocyte activation.

Idiopathic pneumonia syndrome after allogeneic bone marrow transplantation in mice. Role of pretransplant radiation conditioning

Idiopathic pneumonia syndrome (IPS) is a significant clinical problem encountered among patients treated with bone marrow transplantation (BMT). IPS is identified as an inflammatory lung disease characterized by diffuse interstitial pneumonitis and alveolitis leading to interstitial fibrosis in the absence of an identifiable infectious agent. In an earlier study we characterized a murine model of IPS following allogeneic BMT that exhibits several features of human IPS. In this report we show that the lung represents a unique target of post-BMT disease in this model. The kinetics of developing lung disease were found to be markedly different from the kinetics of graft-versus-host disease in other tissues such as liver, colon, ear, skin, and tongue. Mice transplanted by our standard protocol with T-cell-depleted semiallogeneic donor bone marrow plus donor spleen cells in the absence of pretransplant radiation conditioning did not develop lung inflammation or fibrosis characteristic of IPS. Pretransplant radiation conditioning in the absence of BMT also failed to cause IPS, demonstrating an important role for radiation conditioning in the development of BMT-related IPS. The occurrence of lung disease post-BMT was found to be dependent on radiation conditioning in a dose-dependent manner. Finally, thoracic irradiation alone was demonstrated to be sufficient in causing IPS in mice transplanted with bone marrow plus spleen cells, albeit with reduced severity. Based on these findings, we conclude that pretransplant radiation conditioning plays an important role in the development of IPS following allogeneic BMT.

Protein-kinase-specific inhibitors block Langerhans' cell migration by inhibiting interleukin-1alpha release

Previous studies have shown that depletion of Langerhans' cells (LC) from murine epidermis by the superantigen, staphylococcal enterotoxin A (SEA) involves interleukin-1alpha (IL-1alpha) and is inhibitable by agents that block G-protein-associated kinases. The purpose of this study was to determine whether specific kinase inhibitors block LC depletion by inhibiting IL-1alpha release and to ascertain whether LC depletion by SEA involves cell migration. These goals were addressed by measuring the IL-1alpha release within whole or LC-depleted epidermal cell suspensions in the presence of SEA and/or H-7 (an inhibitor of protein kinase C) or H-8 (an inhibitor of G-protein-associated kinases) and by examining the migration of cells with LC markers in SEA-treated skin sections. The results suggest that LC depletion by SEA involves migration and that this migration is blocked by protein kinase inhibitors, at least in part, through inhibition of SEA-induced IL-1alpha release by epidermal cells.

Idiopathic pneumonia syndrome in mice after allogeneic bone marrow transplantation

Pulmonary complications are a major clinical problem following allogeneic bone marrow transplantation (BMT), contributing to more than 30% of transplant-related mortalities. Idiopathic pneumonia syndrome is responsible for significant mortality among BMT patients. However, the etiology of injury to the lung parenchyma by this disease syndrome is unknown and it has been difficult to evaluate the cellular and molecular mechanisms underlying IPS in the absence of a suitable animal model. To study post-BMT lung disease during graft-versus-host disease (GVHD), we have developed a murine model that utilizes a semi-allogeneic parental --> F1 transplant strategy to induce a mild form of GVHD. Progressive inflammatory lung disease developed in animals with mild GVHD, as indicated by changes in immune cell distribution and cytokine expression in the lungs of transplanted animals. Histologic analysis of lung tissue from GVHD mice at 3 wk post-BMT showed minor immunopathologic changes compared with control mice. In contrast, lungs of GVHD mice at 12 wk displayed histopathologic hallmarks of interstitial pneumonitis, such as prominent perilumenal mononuclear cell infiltration and areas of alveolar congestion. Flow cytometric analysis of lung interstitial cells of GVHD mice revealed an increase in CD8+ T-cells at week 3, which decreased to normal levels by week 12 post-BMT. Simultaneously, the percentage of CD4+ T-cells increased progressively above normal levels and peaked at week 7 post-BMT. Analysis of cytokine mRNA expression in lung tissue indicated that steady state levels of interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, interferon-gamma, and IL-12 were significantly elevated in lungs of GVHD mice at 3 wk post-BMT compared with untreated controls. Mice that were transplanted with allogeneic bone marrow alone (BMT controls) also displayed elevated expression of these cytokines, although only IL-6 was significantly higher than in untreated controls. In contrast, at 12 wk after transplantation only TNF-alpha and IL-12 levels remained elevated in GVHD mice, suggesting prolonged macrophage activation. On the basis of these findings, we conclude that allogeneic bone marrow transplantation in this mouse model causes a progressive interstitial pneumonitis, which is characterized by an acute influx of CD8+ T-cells, followed in the chronic phase by a prominent accumulation of CD4+ T-cells, and is associated with persistent production of cytokines known to activate macrophages.

Enhanced cytokine detection by a novel cell culture-based ELISA

Production of some cytokines, such as IL-4 and IL-10, often occurs at low levels and is difficult to detect by standard ELISA techniques. In many cases the level of detection is at or near to the limits of sensitivity of the assay due either to minimal synthesis and/or cytokine consumption. In an effort to enhance the quantitation of weakly detected cytokines we have developed a unique cell culture-capture ELISA. Lymphocytes are incubated in an anti-cytokine antibody coated ELISA plate for the last 6 hours of a 24 hour in vitro activation period. Use of this cell culture capture method consistently enhanced detection of several T cell cytokines compared to conventional ELISA techniques. Moreover, this technique was found to enhance detection without altering the rate of cytokine secretion which occurred prior to the cell culture capture period. Thus, the cell culture capture ELISA may be useful for detection of a variety of cytokines which are produced at low levels and have traditionally been difficult to quantify.

Beta 1 integrins and osteoclast function: involvement in collagen recognition and bone resorption

The extracellular matrix of bone is composed mainly of type I collagen. In this report we studied the role and collagen-binding properties of osteoclast integrins (alpha v, alpha 2, beta 1, and beta 3). Cell adhesion assays with rat osteoclasts and affinity chromatography/SDS-PAGE analysis with purified human osteoclast membranes demonstrated adhesion of osteoclasts to native type I collagen in a divalent cation and Arg-Gly-Asp (RGD)-dependent way via alpha 2 beta 1 integrin, whereas osteoclast adhesion to denatured collagen predominantly involved alpha v beta 3. In receptor-binding assays, the involvement of human recombinant alpha v beta 3 in adhesion to denatured collagen was confirmed. Additionally, osteoclasts adhered to type I collagen fibers and to monomeric types II-V collagen with characteristics similar to those on native monomeric type I collagen. Osteoclastic bone resorption in vitro was inhibited (> 40%) in the presence of alpha 2 and beta 1 antibodies. Using scanning laser confocal microscopy, alpha v beta 3, alpha 2, and beta 1 integrin were detected within podosomes in nonresorbing osteoclasts and in the ruffled border area and basolateral membrane in resorbing osteoclasts, but not in the sealing zone of resorbing osteoclasts. These results demonstrate that alpha 2 beta 1, in addition to alpha v beta 3, has an important role in osteoclast function and acts as a receptor for native, but not denatured, collagen.

Superantigen-induced Langerhans cell depletion is mediated by epidermal cell-derived IL-1 alpha and TNF alpha

The purpose of this study was to examine the role of cytokines in staphylococcal enterotoxin-A (SEA)-induced epidermal Langerhans cell (LS) depletion. This was accomplished by analyzing the effect of SEA on cytokine secretion by cultured epidermal cell populations by means of ELISA and by assessing the capacity of cytokines and cytokine-specific antibodies to affect epidermal LC density (as measured by immunoperoxidase staining of epidermal cells bearing surface Ia). The results of this study indicate that SEA induces the secretion of IL-1 alpha and TNF alpha by epidermal cells, that these cytokines induce LC depletion from epidermis, and that antibodies specific for these agents inhibit the depletion of LC by SEA. Taken together, these findings suggest that IL-1 alpha and TNF alpha may play essential roles in SEA-mediated depletion of LC from murine epidermis.

Structural determinants of calcium signaling by RGD peptides in rat osteoclasts: integrin-dependent and -independent actions

Extensive characterization of the vitronectin receptor (VNR), a member of the integrin group of cell adhesion molecules, which is abundantly expressed in osteoclasts, has revealed a role for this receptor in osteoclast adhesion as well as bone resorption. Earlier evidence from our laboratory suggests that VNR is also capable of transducing intracellular signals following receptor ligand interaction, although this function is poorly understood. Thus, addition of peptides containing the minimal tripeptide Arg-Gly-Asp (RGD) integrin recognition sequence elicits transient increases in intracellular free calcium ions, with maximal responses seen with a bone sialoprotein peptide, BSP-IIA. In the present study we have attempted to determine some of the structural requirements for calcium signaling in osteoclasts using derivatives of the peptide PRGDN/T sequence found in bone sialoprotein. While some peptides, such as the parent sequence PRGDN, can induce both signaling and retractile events, it was found that minor structural modifications yielded peptides such as PRADN which elicited a transient increase in intracellular free calcium ions without promoting a reduction in osteoclast spread area (retraction). Conversely, certain other modifications resulted in peptides, such as PrGDN and benzoyl-RGDN, which effect osteoclast retraction, while having minimal Ca2+ signaling capabilities. Osteoclast adhesion, and hence retraction, are known to be RGD-dependent and integrin-dependent events. However, intracellular Ca2+ signaling is RGD-independent and, based on lack of inhibition by an anti-beta 3 integrin antibody F11 and echistatin, very likely integrin-independent. These data suggest that signaling is not always via VNR and as yet unknown receptors on the osteoclast membrane play a role in osteoclast signaling and hence function.

Langerhans' cell depletion by staphylococcal superantigens

Superantigens were examined for effects on the distribution of Langerhans' cells (LC) in mouse skin. This was accomplished by analysing the expression of LC-specific markers, ATPase and IA among the epidermal portion of cultured sections of mouse skin following treatment with staphylococcal enterotoxins. In this study, treatment of skin sections with staphylococcal enterotoxin A or exfoliative toxin but not toxic shock syndrome toxin led to significant depletion of LC. This depletion was inhibited by agents which specifically block the action of GTP binding proteins or their associated kinases (cholera and pertussis toxins and H-8) as well as those which block protein or RNA synthesis. Therefore, signals which lead to LC depletion in response to staphylococcal enterotoxins appear to involve a cholera and pertussis toxin-sensitive GTP-binding protein and protein synthesis. These requirements are identical to those observed previously for LC depletion following exposure of skin to ultraviolet radiation.