Faculty Bibliography

Background: Studies have revealed the increased incidence of health disorders in First Responders (FR) who were at Ground Zero over the initial 72 hr after the World Trade Center (WTC) collapses. Previous studies in rats exposed to WTC dusts using exposure scenarios that mimicked FR mouthbreathing showed exposure led to altered expression of genes whose products could be involved in lung ailments. Nevertheless, it was uncertain if repeated exposures (as occurred in earliest days post-disaster) might have given rise to long-term changes in the lungs/other organs, in white blood cell (WBC) profiles, and/or systemic expression of select (mostly immune-related) proteins.Methods: To examine this, rats were exposed on 2 consecutive days (2 hr/d, intratracheal inhalation) to WTC dusts and then examined over a 1-yr period thereafter. At select times post-exposure, organ (lung, heart, liver, kidney, spleen) weights, WBC profiles, and blood levels of a variety of proteins were evaluated.Results: The study showed that over the 1-yr period, there were nominal effects on organ weights (absolute, index) as a result of the dust exposures. There were significant changes (relative to in naïve rats) in WBC profiles, with exposed rats having increased monocyte-macrophage and decreased lymphocyte percentages. The study also found that dust exposure led to significant systemic increases in many proteins, including MCP-1, RANTES, MMP-9, RAGE, and Galectin-3.Conclusions: These results provide further support for our longstanding hypothesis that the WTC dusts could potentially have acted as direct inducers of many of the health effects that have been seen in the exposed FR.

Invasive bladder cancer (BC) is one of the most lethal malignant urological tumors. Although miR-200a has been reported as an onco-miRNA that targets the PTEN gene in endometrioid carcinoma, its biological significance in BC invasion has been poorly explored. In the current study, we found that miR-200a was markedly overexpressed in both human BC tissues and BBN-induced muscle-invasive BC tissues. We further showed that miR-200a overexpression specifically promoted human BC cell invasion, but not migration, via transcriptional upregulation of matrix metalloproteinase (MMP)-2. Mechanistic studies indicated that the increased phosphorylation of c-Jun mediated the increasing levels of MMP-2 mRNA transcription. Further investigation revealed that Dicer was decreased in miR-200a overexpressed BC cells; this resulted in inhibition of miR-16 maturation and consequently led to increased JNK2 protein translation and c-Jun activation. Taken together, the studies here showed that miR-200a overexpression inhibited Dicer expression, in turn, resulted in inhibition of miR-16 maturation, leading to upregulation of JNK2 expression, c-Jun phosphorylation, MMP-2 transcription and, ultimately, BC invasion. Collectively, these results demonstrate that miR-200a is an onco-miRNA that is a positive regulator for BC invasion. This finding could be very useful in the ongoing development of new strategies to treat invasive BC patients.

Cancer stem cells (CSC) are highly associated with poor prognosis in cancer patients. Our previous studies report that isorhapontigenin (ISO) down-regulates SOX2-mediated cyclin D1 induction and stem-like cell properties in glioma stem-like cells. The present study revealed that ISO could inhibit stem cell-like phenotypes and invasivity of human bladder cancer (BC) by specific attenuation of expression of CD44 but not SOX-2, at both the protein transcription and degradation levels. On one hand, ISO inhibited cd44 mRNA expression through decreases in Sp1 direct binding to its promoter region-binding site, resulting in attenuation of its transcription. On the other hand, ISO also down-regulated USP28 expression, which in turn reduced CD44 protein stability. Further studies showed that ISO treatment induced miR-4295, which specific bound to 3'-UTR activity of usp28 mRNA and inhibited its translation and expression, while miR-4295 induction was mediated by increased Dicer protein to enhance miR-4295 maturation upon ISO treatment. Our results provide the first evidence that ISO has a profound inhibitory effect on human BC stem cell-like phenotypes and invasivity through the mechanisms distinct from those previously noted in glioma stem-like cells.

World Trade Center (WTC) responders were exposed to mixture of dust, smoke, chemicals and carcinogens. New York University (NYU) and Mount Sinai have recreated WTC exposure in rodents to observe the resulting systemic and local biological responses. These experiments aid in the interpretation of epidemiological observations and are useful for understanding the carcinogenesis process in the exposed human WTC cohort. Here we describe the implementation of a tissue bank system for the rodents experimentally exposed to WTC dust. NYU samples were experimentally exposed to WTC dust via intratracheal inhalation that mimicked conditions in the immediate aftermath of the disaster. Tissue from Mount Sinai was derived from genetically modified mice exposed to WTC dust via nasal instillation. All processed tissues include annotations of the experimental design, WTC dust concentration/dose, exposure route and duration, genetic background of the rodent, and method of tissue isolation/storage. A biobank of tissue from rodents exposed to WTC dust has been compiled representing an important resource for the scientific community. The biobank remains available as a scientific resource for future research through established mechanisms for samples request and utilization. Studies using the WTC tissue bank would benefit from confirming their findings in corresponding tissues from organs of animals experimentally exposed to WTC dust. Studies on rodent tissues will advance the understanding of the biology of the tumors developed by WTC responders and ultimately impact the modalities of treatment, and the probability of success and survival of WTC cancer patients.

An excess incidence of prostate cancer has been identified among World Trade Center (WTC) responders. In this study, we hypothesized that WTC dust, which contained carcinogens and tumor-promoting agents, could facilitate prostate cancer development by inducing DNA damage, promoting cell proliferation, and causing chronic inflammation. We compared expression of immunologic and inflammatory genes using a NanoString assay on archived prostate tumors from WTC Health Program (WTCHP) patients and non-WTC patients with prostate cancer. Furthermore, to assess immediate and delayed responses of prostate tissue to acute WTC dust exposure via intratracheal inhalation, we performed RNA-seq on the prostate of normal rats that were exposed to moderate to high doses of WTC dust. WTC prostate cancer cases showed significant upregulation of genes involved in DNA damage and G₂-M arrest. Cell-type enrichment analysis showed that Th17 cells, a subset of proinflammatory Th cells, were specifically upregulated in WTC patients. In rats exposed to WTC dust, we observed upregulation of gene transcripts of cell types involved in both adaptive immune response (dendritic cells and B cells) and inflammatory response (Th17 cells) in the prostate. Unexpectedly, genes in the cholesterol biosynthesis pathway were also significantly upregulated 30 days after acute dust exposure. Our results suggest that respiratory exposure to WTC dust can induce inflammatory and immune responses in prostate tissue.Implications: WTC-related prostate cancer displayed a distinct gene expression pattern that could be the result of exposure to specific carcinogens. Our data warrant further epidemiologic and cellular mechanistic studies to better understand the consequences of WTC dust exposure.Visual Overview: http://mcr.aacrjournals.org/content/early/2019/06/18/1541-7786.MCR-19-0115/F1.large.jpg.

We present prediction and variable importance (VIM) methods for longitudinal data sets containing continuous and binary exposures subject to missingness. We demonstrate the use of these methods for prognosis of medical outcomes of severe trauma patients, a field in which current medical practice involves rules of thumb and scoring methods that only use a few variables and ignore the dynamic and high-dimensional nature of trauma recovery. Well-principled prediction and VIM methods can provide a tool to make care decisions informed by the high-dimensional patient's physiological and clinical history. Our VIM parameters are analogous to slope coefficients in adjusted regressions, but are not dependent on a specific statistical model, nor require a certain functional form of the prediction regression to be estimated. In addition, they can be causally interpreted under causal and statistical assumptions as the expected outcome under time-specific clinical interventions, related to changes in the mean of the outcome if each individual experiences a specified change in the variable (keeping other variables in the model fixed). Better yet, the targeted MLE used is doubly robust and locally efficient. Because the proposed VIM does not constrain the prediction model fit, we use a very flexible ensemble learner (the SuperLearner), which returns a linear combination of a list of user-given algorithms. Not only is such a prediction algorithm intuitive appealing, it has theoretical justification as being asymptotically equivalent to the oracle selector. The results of the analysis show effects whose size and significance would have been not been found using a parametric approach (such as stepwise regression or LASSO). In addition, the procedure is even more compelling as the predictor on which it is based showed significant improvements in cross-validated fit, for instance area under the curve (AUC) for a receiver-operator curve (ROC). Thus, given that 1) our VIM applies to any model fitting procedure, 2) under assumptions has meaningful clinical (causal) interpretations and 3) has asymptotic (influence-curve) based robust inference, it provides a compelling alternative to existing methods for estimating variable importance in high-dimensional clinical (or other) data.

Clinical studies and the World Trade Center (WTC) Health Registry have revealed increases in the incidence of chronic (non-cancer) lung disorders among first responders (FR) who were at Ground Zero during the initial 72 h after the collapse. Our previous analyses of rats exposed to building-derived WTC dusts using exposure scenarios/levels that mimicked FR mouth-breathing showed that a single WTC dust exposure led to changes in expression of genes whose products could be involved in the lung ailments, but few other significant pathologies. We concluded that rather than acting as direct inducers of many of the FR health effects, it was more likely inhaled WTC dusts instead may have impacted on toxicities induced by other rescue-related co-pollutants present in Ground Zero air. To allow for such effects to occur, we hypothesized that the alkaline WTC dusts induced damage to the normal ability of the lungs to clear inhaled particles. To validate this, rats were exposed on two consecutive days (2 h/d, by intratracheal inhalation) to WTC dust (collected 12-13 September 2001) and examined over a 1-yr period thereafter for changes in the presence of ciliated cells in the airways and hyperplastic goblet cells in the lungs. WTC dust levels in the lungs were assessed in parallel to verify that any changes in levels of these cells corresponded with decreases in host ability to clear the particles themselves. Image analyses of the rat lungs revealed a significant decrease in ciliated cells and increase in hyperplastic goblet cells due to the single series of WTC dust exposures. The study also showed there was only a nominal non-significant decrease (6-11%) in WTC dust burden over a 1-yr period after the final exposure. These results provide support for our current hypothesis that exposure to WTC dusts caused changes in airway morphology/cell composition; such changes could, in turn, have led to potential alterations in the clearance/toxicities of other pollutants inhaled at Ground Zero in the critical initial 72-h period.

Mechanistic pathways underlying inflammatory injury following exposures to vanadium-containing compounds are not defined. We tested the postulate that the in vitro biological effect of vanadium results from its impact on iron homeostasis. Human bronchial epithelial (HBE) cells exposed to vanadyl sulfate (VOSO4) showed a time- and dose-dependent increase in vanadium relative to PBS. HBE cells exposed to VOSO4 and then exposed to ferric ammonium citrate (FAC) significantly increased intracellular iron import supporting an interaction between the two metals. Following exposure to VOSO4, there was an increase (336+/-73%) in RNA for divalent metal transporter 1 (DMT1), a major iron importer. With inclusion of VOSO4 in the incubation, vanadium could be measured in the nuclear and mitochondrial fractions and the supernatant. Non-heme iron in the nuclear and mitochondrial fractions were decreased immediately following VOSO4 exposure while there was an increased concentration of non-heme iron in the supernatant. Provision of excess iron inhibited changes in the concentration of this metal provoked by VOSO4 exposures. Using Amplex Red, VOSO4 was shown to significantly increase oxidant generation by HBE cells in a time- and dose-dependent manner. HBE cells pre-treated with FAC and then exposed to VOSO4 demonstrated a decreased generation of oxidants. Similarly, activation of the transcription factor NF-kB promoter and release of interleukin-6 and -8 were increased following VOSO4 exposure and these effects were diminished by pre-treatment with FAC. We conclude that an initiating event in biological effect after exposure to vanadyl sulfate is a loss of requisite cell iron.