Enhancement of lung tumorigenesis in a Gprc5a Knockout mouse by chronic extrinsic airway inflammation

<p>Abstract</p> <p>Background</p> <p>Although cigarette smoking is the principal cause of lung carcinogenesis, chronic obstructive pulmonary disease (COPD), an inflammatory disease of the lung, has been identified as an independent risk factor for lung cancer. Bacterial colonization, particularly with non-typeable <it>Haemophilus influenzae </it>(NTHi), has been implicated as a cause of airway inflammation in COPD besides cigarette smoke. Accordingly, we hypothesized that lung cancer promotion may occur in a chronic inflammatory environment in the absence of concurrent carcinogen exposure.</p> <p>Results</p> <p>Herein, we investigated the effects of bacterial-induced COPD-like inflammation and tobacco carcinogen-enhanced tumorigenesis/inflammation in the retinoic acid inducible G protein coupled receptor knock out mouse model (Gprc5a-/- mouse) characterized by late-onset, low multiplicity tumor formation. Three-month-old Gprc5a-/- mice received 4 intraperitoneal injections of the tobacco-specific carcinogen, NNK, followed by weekly exposure to aerosolized NTHi lysate for 6 months. The numbers of inflammatory cells in the lungs and levels of several inflammatory mediators were increased in Gprc5a-/- mice treated with NTHi alone, and even more so in mice pretreated with NNK followed by NTHi. The incidence of spontaneous lung lesions in the Gprc5a-/- mice was low, but NTHi exposure led to enhanced development of hyperplastic lesions. Gprc5a-/- mice exposed to NNK alone developed multiple lung tumors, while NTHi exposure increased the number of hyperplastic foci 6-fold and the tumor multiplicity 2-fold. This was associated with increased microvessel density and HIF-1α expression.</p> <p>Conclusion</p> <p>We conclude that chronic extrinsic lung inflammation induced by bacteria alone or in combination with NNK enhances lung tumorigenesis in Gprc5a-/- mice.</p

A Biodistribution and Toxicity Study of Cobalt Dichloride–NAcetyl Cysteine (C4) as an Implantable MRI Marker for Prostate Cancer Treatment

Purpose—C4, a cobalt dichloride–N-acetyl cysteine complex, is being developed as a positivesignal magnetic resonance imaging (MRI) marker to localize implanted radioactive seeds in prostate brachytherapy. We evaluated the toxicity and biodistribution of C4 in rats with the goal of simulating systemic effects of potential leakage from C4 MRI markers within the prostate. Methods—9 μl doses (equivalent to leakage from 120 markers in a human) of control (0.9% sodium chloride), 1% (proposed for clinical use) and 10% C4 solution were injected into the prostates of male Sprague-Dawley rats via laparotomy. Organ toxicity and cobalt disposition in plasma, tissues, feces and urine were evaluated. Results—No C4-related morbidity or mortality was observed in the biodistribution arm (60 rats). Biodistribution was measurable following 10% C4 injection: cobalt was cleared rapidly from periprostatic tissue; mean concentrations in prostate were 163 μg/g and 268 μg/g at 5 and 30 minutes but were undetectable by 60 minutes. Expected dual renal-hepatic elimination was observed with % injected dose recovered in tissues of 39.0 ±5.6% (liver) \u3e 11.8 ±6.5% (prostate) \u3e 5.3 ±0.9% (kidney) with low plasma concentrations detected up to 1 hr (1.40 μg/ml at 5–60 minutes). Excretion in urine was 13.1 ±4.6 % with 3.1 ±0.54 % recovered in feces by 24 hours. In the toxicity arm, three animals died in the control group and 1 each in the 1% and 10% groups from surgical or anesthesia-related complications; all others survived to scheduled termination at 14 days. No C4-related adverse clinical signs or organ toxicity was observed. Conclusion—C4-related toxicity was not observed at exposures at least 10-fold that proposed for human use. This data demonstrating lack of systemic toxicity with dual routes of elimination in the event of in-situ rupture suggests C4 warrants further investigation as an MRI marker for prostate brachytherapy

Pharmacokinetics, clearance, and biosafety of polyethylene glycol-coated hollow gold nanospheres

OBJECTIVE: Gold nanoparticles have attracted enormous interest as potential theranostic agents. However, little is known about the long-term elimination and systemic toxicity of gold nanoparticles in the literature. Hollow gold nanospheres (HAuNS) is a class of photothermal conducting agent that have shown promises in photoacoustic imaging, photothermal ablation therapy, and drug delivery. It’s very necessary to make clear the biosafety of HAuNS for its further application. METHODS: We investigated the cytotoxicity, complement activation, and platelet aggregation of polyethylene glycol (PEG)-coated HAuNS (PEG-HAuNS, average diameter of 63 nm) in vitro and their pharmacokinetics, biodistribution, organ elimination, hematology, clinical chemistry, acute toxicity, and chronic toxicity in mice. RESULTS: PEG-HAuNS did not induce detectable activation of the complement system and did not induce detectable platelet aggregation. The blood half-life of PEG-HAuNS in mice was 8.19 ± 1.4 hr. The single effective dose of PEG-HAuNS in photothermal ablation therapy was determined to be 12.5 mg/kg. PEG-HAuNS caused no adverse effects after 10 daily intravenous injections over a 2-week period at a dose of 12.5 mg/kg per injection (accumulated dose: 125 mg/kg). Quantitative analysis of the muscle, liver, spleen, and kidney revealed that the levels of Au decreased 45.2%, 28.6%, 41.7%, and 40.8%, respectively, from day 14 to day 90 after the first intravenous injection, indicating that PEG-HAuNS was slowly cleared from these organs in mice. CONCLUSION: Our data support the use of PEG-HAuNS as a promising photothermal conducting agent

Comparative Functional Genomics Analysis of NNK Tobacco-Carcinogen Induced Lung Adenocarcinoma Development in Gprc5a-Knockout Mice

Background: Improved understanding of lung cancer development and progression, including insights from studies of animal models, are needed to combat this fatal disease. Previously, we found that mice with a knockout (KO) of G-protein coupled receptor 5A (Gprc5a) develop lung tumors after a long latent period (12 to 24 months). Methodology/Principal Findings: To determine whether a tobacco carcinogen will enhance tumorigenesis in this model, we administered 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) i.p. to 2-months old Gprc5a-KO mice and sacrificed groups (n = 5) of mice at 6, 9, 12, and 18 months later. Compared to control Gprc5a-KO mice, NNK-treated mice developed lung tumors at least 6 months earlier, exhibited 2- to 4-fold increased tumor incidence and multiplicity, and showed a dramatic increase in lesion size. A gene expression signature, NNK-ADC, of differentially expressed genes derived by transcriptome analysis of epithelial cell lines from normal lungs of Gprc5a-KO mice and from NNK-induced adenocarcinoma was highly similar to differential expression patterns observed between normal and tumorigenic human lung cells. The NNK-ADC expression signature also separated both mouse and human adenocarcinomas from adjacent normal lung tissues based on publicly available microarray datasets. A key feature of the signature, up-regulation of Ube2c, Mcm2, and Fen1, was validated in mouse normal lung and adenocarcinoma tissues and cells by immunohistochemistry and western blotting, respectively

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

A study of the role of gp90 in organ-specificity of metastasizing murine melanoma cells

Typescript (photocopy).The role of a surface glycoprotein with a molecular weight of 90,000 (gp90) in determining organ-specificity of metastasizing murine B16 melanoma cells was studied using gp90-specific rabbit antiserum. The specificity of the antiserum was demonstrated by 2-dimensional sodium dodecyl sulfate:polyacrylamide electrophoresis followed by autoradiography of immunoprecipitates of radiolabeled cell membrane lysates of B16 melanoma cells. The antiserum contained antibodies directed against a cell surface protein on B16 melanoma cells with an approximate 90 kilodalton (KD) molecular weight and a pI of 3.5 to 4.5. In one experiment a surface protein with an approximate molecular weight of 180KD coprecipitated with a 90KD protein. Pretreatment of a brain-colonizing subline of B16 melanoma cells with F(ab')(,2) antibody fragments prepared from the gp90-specific rabbit antiserum did not block experimental metastasis to brain in an in vivo experimental metastasis assay. However, there was a statistically significant increase in the number of animals with ovarian experimental metastases in the experimental group compared to the control group. The distribution of gp90 in normal adult tissues was limited to glandular epithelial cells of the endocrine pancreas, anterior pituitary, adrenal medulla, lacrimal gland, sebaseous glands, stomach, duodenum, perifollicular stromal cells of the ovary, and hepatocytes. A large amount of gp90 was found in the gut epithelium of late gestation fetuses but this antigen was absent in early gestation fetuses. Expression of gp90 was demonstrated in all B16 melanoma cell variants tested, but in variable density. In addition, gp90 was variably expressed on established tumor cell lines of different histologic and species origin, being most consistent on melanoma and lymphoma cell lines. The results of this study indicate that gp90 is: (1) a cell surface protein of cellular origin with a pI of 3.5 to 4.5, (2) expressed late in fetal development, (3) expressed on some adult endocrine and certain mesodermal derived tissues that may be related functionally or embryologically, (4) express on all B16 melanoma variants, but with variable density and, (5) distributed in adult mouse tissues in a pattern very similar to the transferrin receptor in adult human tissues; but is not a tissue- or species-specific antigen nor is it directly or solely responsible for B16 cell localization in organ-specific metastasis

Haploinsufficiency of Mdm2 and Mdm4 in Tumorigenesis and Development▿

The tumor suppressor p53 is inactivated by multiple mechanisms that include mutations of the p53 gene itself and increased levels of the p53 inhibitors MDM2 and MDM4. Mice lacking Mdm2 or Mdm4 exhibit embryo-lethal phenotypes that are completely rescued by concomitant deletion of p53. Here we show that Mdm2 and Mdm4 haploinsufficiency leads to increased p53 activity, exhibited as increased sensitivity to DNA damage and decreased transformation potential. Moreover, in in vivo tumor development, Eμ-myc Mdm4+/− mice show a delayed onset of B-cell lymphomas compared to Eμ-myc mice. Additionally, Mdm2+/− Mdm4+/− double-heterozygous mice are not viable and exhibit defects in hematopoiesis and cerebellar development. The defects in Mdm2+/− Mdm4+/− mice are corrected by deletion of a single p53 allele. These findings highlight the exquisite sensitivity of p53 to Mdm2 and Mdm4 levels and suggest that some cell types may be more sensitive to therapeutic drugs that inhibit the Mdm-p53 interaction