Mepolizumab as a Potential Protective Factor of COVID-19 Mortality: A Case Report of Chronic Bronchitis and Asthma in an Elderly Patient

BACKGROUND Patients with multiple comorbidities who are infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have a higher risk of mortality. However, treatment with mepolizumab may be a key factor in counteracting the risk of these comorbidities. We present a patient who had an uneventful recovery from coronavirus disease 2019 (COVID-19), despite having 5 independent risk factors for severe disease and increased mortality. CASE REPORT A 75-year-old man with a long-standing history of asthma, chronic bronchitis, coronary artery disease, and hypertension presented to the Emergency Department in November 2020 with a 4-day history of fever, chills, shortness of breath, cough, and fatigue. Six months prior to this presentation, the patient was hospitalized for severe chronic bronchitis and acute exacerbation of asthma. His medications included mepolizumab, aclidinium, ramipril, diltiazem, aspirin, albuterol sulfate, and micronized budesonide/micronized formoterol fumarate dihydrate. Physical examination was unremarkable, except for cardiopulmonary distress. Laboratory tests showed leucocytosis. His chest X-ray revealed infiltrates and interstitial edema in the lower lung fields. A PCR test for SARS-CoV-2 was positive. COVID-19 pneumonia was diagnosed, and the patient was admitted to the hospital, where he was treated with acetaminophen, amoxicillin, dexamethasone, and supplemental oxygen. The patient remained stable and was discharged from the hospital the following day. He was free of all symptoms after 21 days. CONCLUSIONS This case of a 75-year-old man who presented with mild COVID-19 supports the findings from other reports of improvement in clinical outcomes for some patients with asthma who received treatment with mepolizumab.

Association between the prevalence of obstructive lung disease and the use of aspirin in a diabetic population

Background

Many diabetic patients take a daily low-dose of aspirin because they are two to three times more likely to suffer from heart attacks and strokes, but its role in obstructive lung diseases is less clear.

Methods

A total of 1,003 subjects in community practice settings were interviewed at home. Patients self-reported their personal and clinical characteristics, including any history of obstructive lung disease (including COPD or asthma). Current medications were obtained by the direct observation of medication containers. We performed a cross-sectional analysis of the interviewed subjects to assess for a possible association between obstructive lung disease history and the use of aspirin.

Results

In a multivariate logistic regression model, a history of obstructive lung disease was significantly associated with the use of aspirin even after correcting for potential confounders, including gender, low income (<USD 30,000/year), number of comorbidities, number of medications, cigarette smoking, and alcohol problems (adjusted odds ratio = 0.67, P = 0.03, 95% confidence interval = 0.47, 0.97). The opposite was found with aspirin and that for diabetic individuals that use insulin. A secondary analysis discovered a significant interaction between aspirin use and insulin: aspirin was associated with lower rates of lung disease except among those taking both drugs where the prevalence is significantly higher.

Conclusion

These data suggest a negative correlation between the use of aspirin and obstructive lung disease prevalence in patients with diabetes but not for those that use insulin. Further studies are required to determine if this association is causal.

Association between prevalence of obstructive lung disease and obesity: results from The Vermont Diabetes Information System

BACKGROUND

The association of obesity with the development of obstructive lung disease, namely asthma and/or chronic obstructive pulmonary disease, has been found to be significant in general population studies, and weight loss in the obese has proven beneficial in disease control. Obese patients seem to present with a specific obstructive lung disease phenotype including a reduced response to corticosteroids. Obesity is increasingly recognized as an important factor to document in obstructive lung disease patients and a critical comorbidity to report in diabetic patients, as it may influence disease management. This report presents data that contributes to establishing the relationship between obstructive lung disease in a diabetic cohort, a population highly susceptible to obesity.

METHODS

A total of 1003 subjects in community practice settings were interviewed at home at the time of enrolment into the Vermont Diabetes Information System, a clinical decision support program. Patients self-reported their personal and clinical characteristics, including any history of obstructive lung disease. Laboratory data were obtained directly from the clinical laboratory, and current medications were obtained by direct observation of medication containers. We performed a cross-sectional analysis of the interviewed subjects to assess a possible association between obstructive lung disease history and obesity.

RESULTS

In a multivariate logistic regression model, a history of obstructive lung disease was significantly associated with obesity (body mass index ≥30) even after correcting for potential confounders including gender, low income (<$30,000/year), number of comorbidities, number of prescription medications, cigarette smoking, and alcohol problems (adjusted odds ratio (OR) = 1.58, P = 0.03, 95% confidence interval (CI) = 1.05, 2.37). This association was particularly strong and significant among female patients (OR = 2.18, P = < 0.01, CI = 1.27, 3.72) but not in male patients (OR = 0.97, P = 0.93, CI = 0.51, 1.83).

CONCLUSION

These data suggest an association between obesity and obstructive lung disease prevalence in patients with diabetes, with women exhibiting a stronger association. Future studies are needed to identify the mechanism by which women disproportionately develop obstructive lung disease in this population.

The Kidney-Associated Microbiome of Wild-Caught Artibeus spp. in Grenada, West Indies

Simple Summary

Bats are increasingly being recognized as important integrants of zoonotic disease cycles. Studying bat microbiomes could potentially contribute to the epidemiology of emerging infectious diseases in humans. Furthermore, studying the bat’s microbiome gives us the opportunity to look at the microbiome evolution in mammals. Bat microbiome studies have focused mainly on the gut microbiome, but little is known of the microbiome of the kidney, another potential source of disease transmission. Furthermore, many studies on microbiome found in the literature are based on captive animals, which usually alters the natural microbiome. Here, we analyzed kidney samples of wild-caught Artibeus spp., a fructivorous bat species from Grenada, West Indies, using metagenomics.

Abstract

Bats are capable of asymptomatically carrying a diverse number of microorganisms, including human pathogens, due to their unique immune system. Because of the close contact between bats and humans, there is a possibility for interspecies transmission and consequential disease outbreaks. Herein, high-throughput sequencing was used to determine the kidney-associated microbiome of a bat species abundant in Grenada, West Indies, Artibeus spp. Results indicate that the kidney of these bats can carry potential human pathogens. An endogenous retrovirus, Desmodus rotundus endogenous retrovirus isolate 824, phylogenetically related to betaretroviruses from rodents and New World primates, was also identified.

Potential enhanced association between obstructive lung disease and history of depression in patients with diabetes

BACKGROUND

Depression is one of the most common comorbidities of chronic diseases including diabetes and obstructive lung diseases (emphysema, chronic bronchitis, and asthma). Obstructive lung diseases and depression have few symptoms in common. However, they are both common in adults and associated with chronic inflammation. It is not clear if their coappearance in diabetic patients is coincidental or associated beyond that expected by chance.

METHODS

A total of 1,003 adults with diabetes in community practice settings were interviewed at home at the time of their enrolment into the Vermont Diabetes Information System, a clinical decision support program. Patients self-reported their personal and clinical characteristics, including any obstructive lung disease. Laboratory data were obtained directly from the clinical laboratory, and current medications were obtained by direct observation of medication containers. We performed a cross-sectional analysis of the interviewed subjects to assess a possible association between the prevalence of obstructive lung disease and depression.

RESULTS

In a multivariate logistic regression model, obstructive lung disease was significantly associated with depression even after correcting for gender, obesity (≥30 kg/m²), high comorbidities (>2), low annual income (<$30,000/ year), cigarette smoking, alcohol problems, and education level (odds ratio=1.83; 95% confidence interval 1.27, 2.62; P <0.01).

CONCLUSION

These data suggest a potential enhanced association between obstructive lung disease and depression in patients with diabetes. Future studies are needed to identify if inflammation is implicated in this association as a common denominator.

Metagenomic analysis of Aedes aegypti and Culex quinquefasciatus mosquitoes from Grenada, West Indies

The mosquitoes Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae) and Culex quinquefasciatus Say, 1823 (Diptera: Culicidae) are two major vectors of arthropod-borne pathogens in Grenada, West Indies. As conventional vector control methods present many challenges, alternatives are urgently needed. Manipulation of mosquito microbiota is emerging as a field for the development of vector control strategies. Critical to this vector control approach is knowledge of the microbiota of these mosquitoes and finding candidate microorganisms that are common to the vectors with properties that could be used in microbiota modification studies. Results showed that bacteria genera including Asaia, Escherichia, Pantoea, Pseudomonas, and Serratia are common to both major arboviral vectors in Grenada and have previously been shown to be good candidates for transgenetic studies. Also, for the first time, the presence of Grenada mosquito rhabdovirus 1 is reported in C. quinquefasciatus.

High prevalence of Phasi Charoen-like virus from wild-caught Aedes aegypti in Grenada, W.I. as revealed by metagenomic analysis

Arboviruses cause diseases of significant global health concerns. Interactions between mosquitoes and their microbiota as well as the important role of this interaction in the mosquito's capacity to harbor and transmit pathogens have emerged as important fields of research. Aedes aegypti is one of the most abundant mosquitoes in many geographic locations, a vector capable of transmitting a number of arboviruses such as dengue and Zika. Currently, there are few studies on the metavirome of this mosquito particularly in the Americas. This study analyzes the metavirome of A. aegypti from Grenada, a Caribbean nation with tropical weather, abundant A. aegypti, and both endemic and arboviral pathogens transmitted by this mosquito. Between January and December 2018, 1152 mosquitoes were collected from six semi-rural locations near houses in St. George Parish, Grenada, by weekly trapping using BG-Sentinel traps. From these, 300 A. aegypti were selected for analysis. The metavirome was analyzed using the Illumina HiSeq 1500 for deep sequencing. The generation sequencing library construction protocol used was NuGEN Universal RNA with an average read length of 125 bp. Reads were mapped to the A. aegypti assembly. Non-mosquito reads were analyzed using the tools FastViromeExplorer. The NCBI total virus, RNA virus, and eukaryotic virus databases were used as references. The metagenomic comparison analysis showed that the most abundant virus-related reads among all databases and assemblies was Phasi Charoen-like virus. The Phasi Charoen-like virus results are in agreement to other studies in America, Asia and Australia. Further studies using wild-caught mosquitoes is needed to assess the impact of this insect-specific virus on the A. aegypti lifecycle and vector capacity.

The role of chronic inflammation in obesity-associated cancers

There is a strong relationship between metabolism and immunity, which can become deleterious under conditions of metabolic stress. Obesity, considered a chronic inflammatory disease, is one example of this link. Chronic inflammation is increasingly being recognized as an etiology in several cancers, particularly those of epithelial origin, and therefore a potential link between obesity and cancer. In this review, the connection between the different factors that can lead to the chronic inflammatory state in the obese individual, as well as their effect in tumorigenesis, is addressed. Furthermore, the association between obesity, inflammation, and esophageal, liver, colon, postmenopausal breast, and endometrial cancers is discussed.

Osteopontin modulates inflammation, mucin production, and gene expression signatures after inhalation of asbestos in a murine model of fibrosis

Inflammation and lung remodeling are hallmarks of asbestos-induced fibrosis, but the molecular mechanisms that control these events are unclear. Using laser capture microdissection (LCM) of distal bronchioles in a murine asbestos inhalation model, we show that osteopontin (OPN) is up-regulated by bronchiolar epithelial cells after chrysotile asbestos exposures. In contrast to OPN wild-type mice (OPN(+/+)) inhaling asbestos, OPN null mice (OPN(-/-)) exposed to asbestos showed less eosinophilia in bronchoalveolar lavage fluids, diminished lung inflammation, and decreased mucin production. Bronchoalveolar lavage fluid concentrations of inflammatory cytokines (IL-1β, IL-4, IL-6, IL-12 subunit p40, MIP1α, MIP1β, and eotaxin) also were significantly less in asbestos-exposed OPN(-/-) mice. Microarrays performed on lung tissues from asbestos-exposed OPN(+/+) and OPN(-/-) mice showed that OPN modulated the expression of a number of genes (Col1a2, Timp1, Tnc, Eln, and Col3a1) linked to fibrosis via initiation and cross talk between IL-1β and epidermal growth factor receptor-related signaling pathways. Novel targets of OPN identified include genes involved in cell signaling, immune system/defense, extracellular matrix remodeling, and cell cycle regulation. Although it is unclear whether the present findings are specific to chrysotile asbestos or would be observed after inhalation of other fibers in general, these results highlight new potential mechanisms and therapeutic targets for asbestosis and other diseases (asthma, smoking-related interstitial lung diseases) linked to OPN overexpression.

An association between anti-platelet drug use and reduced cancer prevalence in diabetic patients: results from the Vermont Diabetes Information System Study

Background

Diabetes is associated with an increased risk of several malignancies. Both diabetic patients and patients with cancer have an increase in platelet reactivity and platelet activation has recently emerged as a potential mediator of cancer progression. Drug therapies, such as aspirin, that reduce platelet reactivity reduce both cardiovascular and cancer risk.

Methods

We performed a cross-sectional analysis to assess the association between history of cancer and current anti-platelet drug use in a primary care population of adults with diabetes enrolled in the Vermont Diabetes Information System.

Results

Self-reported characteristics, medical history, and a complete medication list were recorded on 1007 diabetic adults. Fifty percent of diabetic patients used an anti-platelet drug. In unadjusted analysis, no association was seen between anti-platelet drug use and cancer history (OR = 0.93; P = .70). Platelet inhibitor use was associated with a decreased patient-reported history of malignancy in a multivariate logistic regression adjusted for age, sex, body mass index, comorbidity, and number of medications (OR = 0.66; CI 0.44-0.99; P = .045). Similar odds of association were seen in both males and females, and for aspirin and non-aspirin platelet inhibitor therapy.

Conclusions

Our data suggest an association between anti-platelet drug use and reduced cancer prevalence in patients with diabetes. Given the potentially large implications of our observations in the diabetic population, further studies are required to determine if this association is causal.

Alterations in gene expression in human mesothelial cells correlate with mineral pathogenicity

Human mesothelial cells (LP9/TERT-1) were exposed to low and high (15 and 75 microm(2)/cm(2) dish) equal surface area concentrations of crocidolite asbestos, nonfibrous talc, fine titanium dioxide (TiO2), or glass beads for 8 or 24 hours. RNA was then isolated for Affymetrix microarrays, GeneSifter analysis and QRT-PCR. Gene changes by asbestos were concentration- and time-dependent. At low nontoxic concentrations, asbestos caused significant changes in mRNA expression of 29 genes at 8 hours and of 205 genes at 24 hours, whereas changes in mRNA levels of 236 genes occurred in cells exposed to high concentrations of asbestos for 8 hours. Human primary pleural mesothelial cells also showed the same patterns of increased gene expression by asbestos. Nonfibrous talc at low concentrations in LP9/TERT-1 mesothelial cells caused increased expression of 1 gene Activating Transcription Factor 3 (ATF3) at 8 hours and no changes at 24 hours, whereas expression levels of 30 genes were elevated at 8 hours at high talc concentrations. Fine TiO2 or glass beads caused no changes in gene expression. In human ovarian epithelial (IOSE) cells, asbestos at high concentrations elevated expression of two genes (NR4A2, MIP2) at 8 hours and 16 genes at 24 hours that were distinct from those elevated in mesothelial cells. Since ATF3 was the most highly expressed gene by asbestos, its functional importance in cytokine production by LP9/TERT-1 cells was assessed using siRNA approaches. Results reveal that ATF3 modulates production of inflammatory cytokines (IL-1 beta, IL-13, G-CSF) and growth factors (VEGF and PDGF-BB) in human mesothelial cells.

Association of angiotensin-converting enzyme inhibitor therapy and comorbidity in diabetes: results from the Vermont diabetes information system

BACKGROUND

Angiotensin converting enzyme inhibitors (ACE inhibitors) reduce peripheral vascular resistance via blockage of angiotensin converting enzyme (ACE). ACE inhibitors are commonly used to treat congestive heart failure and high blood pressure, but other effects have been reported. In this study, we explored the association between ACE inhibitor therapy and the prevalence of comorbid conditions in adults with diabetes

METHODS

We surveyed 1003 adults with diabetes randomly selected from community practices. Patients were interviewed at home and self-reported their personal and clinical characteristics including comorbidity. Current medications were obtained by direct observation of medication containers. We built logistic regression models with the history of comorbidities as the outcome variable and the current use of ACE inhibitors as the primary predictor variable. We adjusted for possible confounding by social (age, sex, alcohol drinking, cigarette smoking) and clinical factors (systolic blood pressure, body mass index (BMI), glycosolated hemoglobin (A1C), number of comorbid conditions, and number of prescription medications).

RESULTS

ACE users reported a history of any cancer (except the non-life-threatening skin cancers) less frequently than non-users (10% vs. 15%; odd ratio = 0.59; 95% confidence interval [0.39, 0.89]; P = 0.01); and a history of stomach ulcers or peptic ulcer disease less frequently than non-users (12% vs. 16%, odd ratio = 0.70, [0.49, 1.01], P = 0.06). After correcting for potential confounders, ACE inhibitors remained significantly inversely associated with a personal history of cancer (odds ratio = 0.59, [0.39, 0.89]; P = 0.01) and peptic ulcer disease (odd ratio = 0.68, [0.46, 1.00], P = 0.05).

CONCLUSION

ACE inhibitor use is associated with a lower likelihood of a history of cancer and peptic ulcers in patients with diabetes. These findings are limited by the cross sectional study design, self-report of comorbid diagnoses, and lack of information on the timing and duration of ACE inhibitor use. Further research is needed to confirm these associations and understand their mechanisms.

In vitro Cytotoxic Activity of Sesamin Isolated from Vismia baccifera var. dealbata Triana & Planch (Guttiferae) Collected from Venezuela

Sesamin extracted from Vismia baccifera var. dealbata was demonstrated to have cytostatic activity on the cancer cell lines tested, particularly the lung cancer cell line, with an IC50 of 1 g/L.

A novel combination: ranpirnase and rosiglitazone induce a synergistic apoptotic effect by down-regulating Fra-1 and Survivin in cancer cells

Accumulating evidence supports the idea that two known phosphatidylinositol 3'-kinase (PI3K) downstream proteins, Fra-1 and Survivin, are potential targets for cancer therapy. Increased expression of Fra-1, a Fos family member of the transcription factor activator protein-1, has been implicated in both the maintenance and the progression of the transformed state of several cancer cells. In addition, high Survivin expression in tumors correlates with more aggressive behavior, lower response to chemotherapeutic drugs, and shortened survival time. Previously, we reported that, in malignant mesothelioma cells with increased PI3K activity, small-molecule inhibitors of the PI3K/AKT pathway acted cooperatively with the amphibian RNase chemotherapeutic drug ranpirnase to inhibit cell growth. Because the thiazolidinedione antidiabetic drug rosiglitazone targets the PI3K/AKT pathway, we investigated the effect of the combination of these two drugs in cell survival in several cancer cell lines. We show here that the combination of ranpirnase and rosiglitazone synergistically decreases cell viability and increases cell apoptosis in several cancer cell lines. Cell killing is associated with decreased Fra-1 and Survivin expression and knockdown of Fra-1 increases cell killing by ranpirnase in a dose-dependent manner but not by rosiglitazone. The drug combination does not have a synergistic effect on killing in Fra-1 knockdown cells, showing that Fra-1 modulation accounts in part for the synergism. The novel drug combination of ranpirnase and rosiglitazone is a promising combination to treat cancers with increased PI3K-dependent Fra-1 expression or Survivin.

Fra-1 governs cell migration via modulation of CD44 expression in human mesotheliomas

Silencing of Fra-1, a component of the dimeric transcription factor, activator protein-1 (AP-1), inhibits mRNA expression of c-met and cd44 in rat mesothelioma cells and is causally linked to maintenance of the transformed phenotype. However, the mechanisms of Fra-1 regulation and Fra-1 regulated gene expression in human malignant mesothelioma (MM) are unclear. We first show in a panel of human MM cells that Fra-1 mRNA expression in MM is complex and regulated by extracellular signal-regulated kinase (ERK1, ERK2), Src, and phosphatidyl-inositol-3-kinase (PI3K) pathways in a tumor-specific fashion. Cell lines with PI3K-dependent Fra-1 expression were SV40 positive and expressed the lowest basal Fra-1 levels. Levels of Fra-1 expression correlated with amounts of CD44 expression that were greater in simian virus 40 negative (SV40-) MM cells. Using dominant negative (dn), short hairpin (sh) and small interference (si) RNA constructs, we next demonstrate that expression of CD44, the principal hyaluronic receptor in MMs, correlates with Fra-expression in both simian virus 40 positive (SV40+) and SV40- MMs. Moreover, both Fra-1 and CD44 expression are linked to cell migration in SV40- MM cells. Lastly, in contrast to normal lung tissue, tissue microarrays revealed that Fra-1 was expressed in 33 of 34 human MMs, and that all CD44+ tumors were SV40-. These results suggest that Fra-1 is associated with cell migration in human MMs and that Fra-1 modulation of CD44 may govern migration of selected MMs.

HGF mediates cell proliferation of human mesothelioma cells through a PI3K/MEK5/Fra-1 pathway

The ligand hepatocyte growth factor/scatter factor (HGF) and its receptor tyrosine kinase, c-Met, are highly expressed in most human malignant mesotheliomas (MMs) and may contribute to their increased growth and viability. Based upon our observation that RNA silencing of fos-related antigen 1 (Fra-1) inhibited c-met expression in rat mesotheliomas (1), we hypothesized that Fra-1 was a key player in HGF-induced proliferation in human MMs. In three of seven human MM lines evaluated, HGF increased Fra-1 levels and phosphorylation of both extracellular signal-regulated kinase 5 (ERK5) and AKT that were inhibited by the phosphatidylinositol 3-kinase (PI3K) inhibitor, LY290042. HGF-dependent phosphorylation and Fra-1 expression were decreased after knockdown of Fra-1, whereas overexpression of Fra-1 blocked the expression of mitogen/extracellular signal-regulated kinase kinases (MEK)5 at the mRNA and protein levels. Stable MM cell lines using a dnMEK5 showed that basal Fra-1 levels were increased in comparison to empty vector control lines. HGF also caused increased MM cell viability and proliferating cell nuclear antigen (PCNA) expression that were abolished by knockdown of MEK5 or Fra-1. Data suggest that HGF-induced effects in some MM cells are mediated via activation of a novel PI3K/ERK5/Fra-1 feedback pathway that might explain tumor-specific effects of c-Met inhibitors on MM and other tumors.

Association between cancer prevalence and use of thiazolidinediones: results from the Vermont Diabetes Information System

BACKGROUND

Peroxisome proliferator-activated receptors (PPARs) have emerged as important drug targets for diabetes. Drugs that activate PPARgamma, such as the thiazolidinediones (TZDs), are widely used for treatment of Type 2 diabetes mellitus. PPARgamma signaling could also play an anti-neoplastic role in several in vitro models, although conflicting results are reported from in vivo models. The effects of TZDs on cancer risk in humans needs to be resolved as these drugs are prescribed for long periods of time in patients with diabetes.

METHODS

A total of 1003 subjects in community practice settings were interviewed at home at the time of enrolment into the Vermont Diabetes Information System, a clinical decision support program. Patients self-reported their personal and clinical characteristics, including any history of malignancy. Laboratory data were obtained directly from the clinical laboratory and current medications were obtained by direct observation of medication containers. We performed a cross-sectional analysis of the interviewed subjects to assess a possible association between cancer diagnosis and the use of TZDs.

RESULTS

In a multivariate logistic regression model, a diagnosis of cancer was significantly associated with TZD use, even after correcting for potential confounders including other oral anti-diabetic agents (sulfonylureas and biguanides), age, glycosylated hemoglobin A1C, body mass index, cigarette smoking, high comorbidity, and number of prescription medications (odds ratio = 1.59, P = 0.04). This association was particularly strong among patients using rosiglitazone (OR = 1.89, P = 0.02), and among women (OR = 2.07, P = 0.01).

CONCLUSION

These data suggest an association between TZD use and cancer in patients with diabetes. Further studies are required to determine if this association is causal.

Unique uptake of acid-prepared mesoporous spheres by lung epithelial and mesothelioma cells

Lung cancers, malignant mesotheliomas (MM), and fibrosis are devastating diseases with limited treatment strategies, in part due to poorly-effective drug delivery to affected areas of lung. We hypothesized that acid-prepared mesoporous spheres (APMS) (1-2 microm diameter, 40 A pore size) might be effective vehicles for pulmonary chemotherapeutic drug delivery. To assess this, APMS, chemically modified with different surface molecules (lipid, a linker having a terminal amine group, a thiol group, or tetraethylene glycol [TEG]), were evaluated for uptake and possible cytotoxic effects after in vitro administration to murine alveolar epithelial Type II (C10) and human mesothelioma (MM) cells and after intrapleural or intranasal administration to C57Bl/6 mice. APMS coated with TEG (APMS-TEG) were most efficiently taken up by C10 and MM cells. The mechanism of cell uptake was rapid, actin-dependent, and did not involve clathrin- or caveolae-mediated mechanisms nor fusion of membrane-bound APMS with lysosomes. When injected intrapleurally in mice, APMS-TEG were taken up by both CD45-positive and -negative cells of the diaphragm, lung, and spleen, whereas APMS administered by the intranasal route were predominantly in lung epithelial cells and alveolar macrophages. After intrapleural or intranasal administration, APMS were nonimmunogenic and nontoxic as evaluated by differential cell counts and lactate dehydrogenase levels in bronchoalveolar and pleural lavage fluids. In the treatment of lung and pleural diseases, APMS-TEG may be useful tools to deliver chemotherapeutic drugs or molecular constructs.

Cellular and molecular parameters of mesothelioma

Malignant mesotheliomas (MM) are neoplasms arising from mesothelial cells that line the body cavities, most commonly the pleural and peritoneal cavities. Although traditionally recognized as associated with occupational asbestos exposures, MMs can appear in individuals with no documented exposures to asbestos fibers, and emerging data suggest that genetic susceptibility and simian virus 40 (SV40) infections also facilitate the development of MMs. Both asbestos exposure and transfection of human mesothelial cells with SV40 large and small antigens (Tag, tag) cause genetic modifications and cell signaling events, most notably the induction of cell survival pathways and activation of receptors, and other proteins that favor the growth and establishment of MMs as well as their resistance to chemotherapy. Recent advances in high-throughput technologies documenting gene and protein expression in patients and animal models of MMs can now be validated in human MM tissue arrays. These have revealed expression profiles that allow more accurate diagnosis and prognosis of MMs. More importantly, serum proteomics has revealed two new candidates (osteopontin and serum mesothelin-related protein or SMRP) potentially useful in screening individuals for MMs. These mechanistic approaches offer new hope for early detection and treatment of these devastating tumors.

Human and mouse mesotheliomas exhibit elevated AKT/PKB activity, which can be targeted pharmacologically to inhibit tumor cell growth

Malignant mesotheliomas (MMs) are very aggressive tumors that respond poorly to standard chemotherapeutic approaches. The phosphatidylinositol 3-kinase (PI3K)/AKT pathway has been implicated in tumor aggressiveness, in part by mediating cell survival and reducing sensitivity to chemotherapy. Using antibodies recognizing the phosphorylated/activated form of AKT kinases, we observed elevated phospho-AKT staining in 17 of 26 (65%) human MM specimens. In addition, AKT phosphorylation was consistently observed in MMs arising in asbestos-treated mice and in MM cell xenografts. Consistent with reports implicating hepatocyte growth factor (HGF)/Met receptor signaling in MM, all 14 human and murine MM cell lines had HGF-inducible AKT activity. One of nine human MM cell lines had elevated AKT activity under serum-starvation conditions, which was associated with a homozygous deletion of PTEN, the first reported in MM. Treatment of this cell line with the mTOR inhibitor rapamycin resulted in growth arrest in G1 phase. Treatment of MM cells with the PI3K inhibitor LY294002 in combination with cisplatin had greater efficacy in inhibiting cell proliferation and inducing apoptosis than either agent alone. Collectively, these data indicate that MMs frequently express elevated AKT activity, which may be targeted pharmacologically to enhance chemotherapeutic efficacy. These findings also suggest that mouse models of MM may be useful for future preclinical studies of pharmaceuticals targeting the PI3K/AKT pathway.

Human mesothelioma cells exhibit tumor cell–specific differences in phosphatidylinositol 3-kinase/AKT activity that predict the efficacy of Onconase

Malignant mesothelioma is an aggressive cancer with no known cure, which has become a therapeutic challenge. Onconase is one of few chemotherapeutic agents that have been studied in patients with malignant mesothelioma that has the advantage of low toxicity and limited side effects. Here, we evaluate the effect of Onconase on killing of malignant mesothelioma cells and how the phosphatidylinositol 3-kinase/AKT (PI3-K/AKT) survival pathway influences this effect. Our results show that Onconase induces apoptosis in malignant mesothelioma cell lines and that this effect is tumor cell specific. Malignant mesothelioma cell lines with the highest AKT activation, which correlated with the presence of the SV40 large and small T antigen (SV40+), were the most resistant to the drug. Finally, a cooperative effect was observed between small molecule inhibitors of PI3-K and Onconase in the killing of malignant mesothelioma cells. Our results suggest that kinase screening of individual malignant mesotheliomas for endogenous levels of activated PI3-K/AKT may be predictive of the efficacy of Onconase and possibly other chemotherapeutic agents.

Src-dependent ERK5 and Src/EGFR-dependent ERK1/2 activation is required for cell proliferation by asbestos

Crocidolite asbestos elicits oxidative stress and cell proliferation, but the signaling cascades linked to these outcomes are unclear. To determine the role of mitogen-activated protein kinases (MAPK) in asbestos-induced cell signaling, we evaluated the effects of crocidolite asbestos, EGF and H2O2, on MAPK activation in murine lung epithelial cells (C10 line). In contrast to rapid and transient activation of extracellular signal-regulated kinase 5 (ERK5) by EGF or H2O2, asbestos caused protracted oxidant-dependent ERK5 activation that was inhibited by an Src kinase inhibitor (PP2), but not by an inhibitor of epidermal growth factor receptor (EGFR) phosphorylation (AG1478). ERK1/2 activation by asbestos was inhibited by either PP2 or AG1478. To confirm the involvement of Src in ERK1/2 and ERK5 activation, a dominant-negative Src construct was used. These experiments showed that Src was essential for ERK1/2 and also ERK5 phosphorylation by asbestos. Time frame studies indicated immediate activation of Src by asbestos fibers, whereas EGFR phosphorylation occurred subsequently. Data suggest that asbestos causes activation of ERK5 through an EGFR-independent pathway, whereas ERK1/2 activation is dependent on Src through a mechanism involving phosphorylation of the EGFR. Furthermore, Src, ERK1/2 and ERK5 activation are essential for cell proliferation by asbestos. The use of a dominant-negative ERK5 construct caused selective downregulation of c-jun expression, whereas inhibition of Src by PP2 or MEK1 by PD98059 caused decreases in c-fos, fra-1 and c-jun expression in asbestos-exposed C10 cells. These observations may have broad relevance to cell proliferation by carcinogenic mineral fibers and oxidants.

Microarray analysis and RNA silencing link fra-1 to cd44 and c-met expression in mesothelioma

Malignant mesothelioma is a cancer with poor prognosis associated with exposures to asbestos. The mechanisms of asbestos-induced mesotheliomas are unclear, and studies are required to find diagnostic tools and therapies to improve the survival rates of patients. After oligonucleotide microarray analysis (Affymetrix array) of normal rat pleural mesothelial (RPM) cells, RPM cells exposed to crocidolite asbestos, and rat mesotheliomas, subsets of genes that changed in expression were categorized, including the highly up-regulated, early response proto-oncogene, fra-1. Increases in fra-1 in both rat and human mesotheliomas and a subset of genes common to both asbestos-exposed RPM cells and mesotheliomas that mimicked fra-1 patterns of expression were subsequently confirmed using real-time quantitative PCR. Using RNA interference technology, fra-1 gene silenced RPM cells were assayed by real-time quantitative PCR for the expression of possible fra-1-regulated genes. Results reveal that induction of cd44 and c-met is causally linked to fra-1 expression, connecting fra-1 with genes governing cell motility and invasion in mesothelioma. These studies suggest that inhibition of fra-1 signaling pathways may be a strategy for therapy of malignant mesothelioma.

Mesothelial cell transformation requires increased AP-1 binding activity and ERK-dependent Fra-1 expression

Mesothelioma is a unique and insidious tumor associated historically with occupational exposure to asbestos. The transcription factor, activator protein-1 (AP-1) is a major target of asbestos-induced signaling pathways. Here, we demonstrate that asbestos-induced mesothelial cell transformation is linked to increases in AP-1 DNA binding complexes and the AP-1 component, Fra-1. AP-1 binding to DNA was increased dramatically in mesothelioma cell lines in comparison to isolated rat pleural mesothelial (RPM) cells. Elevated levels of AP-1 complexes, including significant increases in c-Jun, JunB and Fra-1, were found in asbestos-exposed RPM cells, but only Fra-1 expression was significantly increased and protracted in both asbestos-exposed RPM cells and mesothelioma cell lines. Asbestos-induced Fra-1 expression in RPM cells was dependent on stimulation of the extracellular signal-regulated kinases (ERKs 1/2). Inhibition of ERK phosphorylation or transfection with dominant-negative fra-1 constructs reversed the transformed phenotype of mesothelioma cells and anchorage-independent growth in soft agar. In summary, we demonstrate that ERK-dependent Fra-1 is elevated in AP-1 complexes in response to asbestos fibers and is critical to the transformation of mesothelial cells.

Role of mitogen-activated protein kinases (MAPK) in cell injury and proliferation by environmental particulates

Cell signaling pathways may be initiated by environmental particulates by indirect mechanisms such as elaboration of reactive oxygen or nitrogen species (ROS/RNS) or directly upon contact of particulates with the plasma membrane and uptake by epithelial or mesothelial cells. Research in the last few years has mainly addressed cell signaling cascades leading to activation of the redox-sensitive transcription factors, nuclear factor kappa-B (NF-kappaB), and activator protein-1 (AP-1). The activation of these transcription factors may be linked to increases in gene expression controlling cell injury or apoptosis, proliferation and/or cell survival, and inflammatory cytokines. Here, we provide an overview of the MAPK signaling pathways and their activation by asbestos, specifically the role of ROS, receptor-dependent and independent activation via the epidermal growth factor receptor (EGFR), and strategies for proving causal relationships between these pathways and changes in epithelial cell phenotype linked to disease causation.

QSARs for the effect of benzaldehydes on foodborne bacteria and the role of sulfhydryl groups as targets of their antibacterial activity

Quantitative structure activity relationships (QSARs) were obtained describing the activity of a series of benzaldehydes against three different foodborne bacteria, Listeria monocytogenes F6861, serotype 4b, Salmonella enteritidis, Phage type 4, P167807 and Lactobacillus plantarum INT.L11. MIC values at pH 6.2 and 35 degrees C were obtained for 11 phenolic benzaldehydes to produce multiple linear regression and artificial neural network models. For each organism, the models contained a steric parameter Vw and an electronic-steric parameter for ortho substituents Es degree. The benzaldehydes did not require to partition to produce their effect, shown by the lack of a lipophilic parameter in the models. This strongly suggests that they act on the outside of the cells. Substitution ortho to the carbonyl group increased their antibacterial action. Cells were treated with 2,3-dihydroxy benzaldehyde and examined for their ability to bind radiolabelled iodoacetate to envelope sulfhydryl groups that remained available. It was shown that the accumulation of radiolabelled iodoacetate was lower after treatment, indicating possible competition between these two compounds for the same target. The order of the sensitivity to benzaldehydes (Salmonella > Listeria > Lactobacillus) correlated with the number of surface sulfhydryl groups available, being highest for Salmonella.

A comparison of quantitative structure-activity relationships for the effect of benzoic and cinnamic acids on Listeria monocytogenes using multiple linear regression, artificial neural network and fuzzy systems

The ability of artificial neural networks (ANN), fuzzy systems (FS) and multiple linear regression (MLR) to fit the biological activity surface describing the inhibition of Listeria monocytogenes by benzoic and cinnamic acid derivatives was compared. MLR and ANN were also compared for their ability to select the properties that best describe the biological activity of the compounds. The criteria used for comparing surface fits of all models were the coefficient of determination r2 and the standard deviation of the error, s(e). The ANN method gave a better correlation, r2 = 0.96, compared with either MLR, r2 = 0.81, or FS, r2 = 0.92, and also a lower standard error, possibly indicating non-linearity in the data. The ANN was shown to generalize better than MLR using the leave-one-out method. The ANN selection algorithm for the selection of the parameters that contributed most to the biological activity of the phenols (log K and pKa) agreed with the selected parameters of the MLR system.

Quantitative structure activity relationship for the effect of benzoic acids, cinnamic acids and benzaldehydes on Listeria monocytogenes

The inhibition of a cocktail of 18 strains of Listeria monocytogenes by 24 mono-, di- and tri-substituted benzoic and cinnamic acids and 16 benzaldehydes was evaluated using the concentration (C) required to give a 50% growth inhibition under anaerobic conditions at 35 degree C and pH 6.2 as a measure of biological activity (BAV). Using the method of least squares, multiple regression equations were obtained which described the contribution of some physiochemical and other structural properties of the compounds to their biological activity. The equation that best described the activity of benzoic and cinnamic acids was [formula: see text] where K is a lipophilicity parameter determined by RP-HPLC and the effect of ionization is represented by pKa. Benzaldehydes behaved differently, their activity being best described by the equation. [formula: see text] where the activity is controlled by a steric parameter, the van der Waals volume (Vw), and an electronic-steric parameter for ortho substituents. Absence of a lipophilicity parameter indicates that partitioning into the cell membrane might not be required for antimicrobial activity. The models were tested in several food systems which showed that in food with a high protein or lipid content antilisterial activity was much lower than predicted, making the models unacceptable in such circumstances.