Project description:Recent in vivo studies reported that inhaled carbon nanotube distribute in the alveolar region resulting in an acute inflammation, progressive fibrotic response and particle accumulation at the bronchoalveolar junction with low clearance. With similar biopersistence and shape as asbestos, a known lung carcinogen, growing concern has arisen for elevated risk of carbon nanotube-induced lung carcinogenesis; however few studies have evaluated long-term human health risks associated with chronic pulmonary carbon nanotube exposures compared to asbestos. To address this knowledge gap, we conducted subchronic in vitro exposures of dispersed single walled carbon nanotube, multi-walled carbon nanotube and crocidolite asbestos to human small airway epithelial cells to assess their neoplastic transformation potential. Subchronic single-, multi-walled carbon nanotube and asbestos exposures caused human lung cell neoplastic transformation exhibited by increased proliferation, anchorage-independent growth, invasion and angiogenesis. Whole genome profiling and protein expression analyses showed that carbon nanotube-induced transformation mechanism(s) was largely different from asbestos-related inflammatory signaling, suggesting specific carbon nanotube-induced carcinogenic potential. This study provides novel carbon nanotube and asbestos toxicogenomic information for risk assessment and an in vitro model to evaluate transformation potential of carbon nanotubes and other nanoparticles. Whole genome expression profiling was conducted on human immortalized small airway epithelial cells (SAEC-hTERT) following 6 month in vitro chronic exposure to six separate treatments to assess differences in carbon nanotube (CNT) vs. asbestos potential tumorigenesis signaling. Dispersed single wall CNT (D-SWCNT), multi-wall CNT (D-MWCNT), ultrafine carbon black (D-UFCB), crocidolite asbestos (ASB) and saline (SAL) exposed cells were compared to SurvantaM-BM-. dispersant (DISP) passage control cells. Each treatment possessed 3 biological cDNA replicates. One technical replicate was performed per biological sample.
Project description:Malignant mesothelioma is one of the most aggressive forms of cancer known. Recent studies have shown that carbon nanotubes (CNTs) are biopersistent and induce mesothelioma in animals, but the underlying mechanisms are not known. Here, we investigate the effect of long-term exposure to CNTs on the aggressive behaviors of human pleural mesothelial cells, the primary cellular target of human lung mesothelioma. We show that sub-chronic exposure (4 month) to single- and multi-walled CNTs induced proliferation, migration and invasion of the cells similar to that observed in asbestos-exposed cells. An up-regulation of several key genes known to be important in cell invasion, notably matrix metalloproteinase-2 (MMP-2), was observed in the exposed mesothelial cells as determined by real-time PCR. Western blot and enzyme activity assays confirmed the increased expression and activity of MMP-2. Whole genome expression microarray analysis further indicated the importance of MMP-2 in the invasion gene signaling network of the exposed cells. Knockdown of MMP-2 in CNT and asbestos-exposed cells by shRNA-mediated gene silencing effectively inhibited the aggressive phenotypes. This study provides new evidence for CNT-induced cell invasion and indicates the role of MMP-2 in the process. Whole genome expression profiling was conducted on human immortalized pleural mesothelial cells (MeT5A) following 4 month in vitro sub-chronic exposure to six separate treatments to assess differences in carbon nanotube (CNT) vs. asbestos potential tumorigenesis signaling. Dispersed single wall CNT (D-SWCNT), multi-wall CNT (D-MWCNT), crocidolite asbestos (ASB) and saline (SAL) exposed cells were compared to Survanta® dispersant (DISP) passage control cells. DISP and SAL cells served as control treatments for CNT- and ASB-exposed cells, respectively. Each treatment possessed 3 biological cDNA replicates. One technical replicate was performed per biological sample.
Project description:Recent in vivo studies reported that inhaled carbon nanotube distribute in the alveolar region resulting in an acute inflammation, progressive fibrotic response and particle accumulation at the bronchoalveolar junction with low clearance. With similar biopersistence and shape as asbestos, a known lung carcinogen, growing concern has arisen for elevated risk of carbon nanotube-induced lung carcinogenesis; however few studies have evaluated long-term human health risks associated with chronic pulmonary carbon nanotube exposures compared to asbestos. To address this knowledge gap, we conducted subchronic in vitro exposures of dispersed single walled carbon nanotube, multi-walled carbon nanotube and crocidolite asbestos to human small airway epithelial cells to assess their neoplastic transformation potential. Subchronic single-, multi-walled carbon nanotube and asbestos exposures caused human lung cell neoplastic transformation exhibited by increased proliferation, anchorage-independent growth, invasion and angiogenesis. Whole genome profiling and protein expression analyses showed that carbon nanotube-induced transformation mechanism(s) was largely different from asbestos-related inflammatory signaling, suggesting specific carbon nanotube-induced carcinogenic potential. This study provides novel carbon nanotube and asbestos toxicogenomic information for risk assessment and an in vitro model to evaluate transformation potential of carbon nanotubes and other nanoparticles.
Project description:Human mesothelial cells (LP9/TERT-1) were exposed to low and high (15 and 75 μm2/cm2 dish) equal surface area concentrations of crocidolite asbestos, nonfibrous talc, fine titanium dioxide (TiO2), or glass beads for 8 or 24 h. 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 h and 205 genes at 24 h, whereas changes in mRNA levels of 236 genes occurred in cells exposed to high concentrations of asbestos for 8 h. 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 h and no changes at 24 h, whereas expression levels of 30 genes were elevated at 8 h 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 2 genes (NR4A2, MIP2) at 8 h and 16 genes at 24 h 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-1β, IL-13, G-CSF) and growth factors (VEGF and PDGF-BB) in human mesothelial cells.
Project description:We hypothesize that the observed differences in incidences of pleural and peritoneal malignant mesothelioma (MM) are the result of differences in the direct response of these cell types to asbestos rather than to differences mediated by the in vivo microenvironment. To test this hypothesis, we characterized cellular responses to asbestos in a controlled environment using high-throughput RNA sequence and other assays. Examination of asbestos-treated versus untreated mesothelial cells from four cell lines representing two tissue types in culture.
Project description:Human mesothelial cells (LP9/TERT-1) were exposed to low and high (15 and 75 μm2/cm2 dish) equal surface area concentrations of crocidolite asbestos, nonfibrous talc, fine titanium dioxide (TiO2), or glass beads for 8 or 24 h. 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 h and 205 genes at 24 h, whereas changes in mRNA levels of 236 genes occurred in cells exposed to high concentrations of asbestos for 8 h. 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 h and no changes at 24 h, whereas expression levels of 30 genes were elevated at 8 h 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 2 genes (NR4A2, MIP2) at 8 h and 16 genes at 24 h 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-1β, IL-13, G-CSF) and growth factors (VEGF and PDGF-BB) in human mesothelial cells. Microarrays were performed on samples from 3 independent experiments. All cell types, time points, and mineral types and concentrations were included in all 3 experiments. For each experiment, n=3 dishes were pooled into one sample per treatment group. Each of the pooled samples was analyzed on a separate array, i.e., n=3 arrays per condition (3 independent biological replicates). We tested the hypothesis that alteration in gene expression in human cells correlate with mineral pathogenicity. We used GeneSifter program to analyze our data and pairwise analysis showed that number of gene changes correlate with toxicity of pathogenic minerals. While non-pathogenic minerals glass beads and fine TiO2 treatment to cell resulted in no gene change, crocidolite asbestos caused maximum number of gene changes followed by talc.
Project description:Pulmonary exposure to multiwalled carbon nanotubes (MWCNT) induces an inflammatory and rapid fibrotic response, although the long-term signaling mechanisms are unknown. The aim of this study was to examine the effects of 1, 10, 40, or 80 µg MWCNT administered by pharyngeal aspiration on bronchoalveolar lavage (BAL) fluid for polymorphonuclear cell (PMN) infiltration, lactate dehydrogenase (LDH) activity, and lung histopathology for inflammatory and fibrotic responses in mouse lungs 1 mo, 6 mo, and 1 yr postexposure. Further, a 120-µg crocidolite asbestos group was incorporated as a positive control for comparative purposes. Results showed that MWCNT increased BAL fluid LDH activity and PMN infiltration in a dose-dependent manner at all three postexposure times. Asbestos exposure elevated LDH activity at all 3 postexposure times and PMN infiltration at 1 mo and 6 mo postexposure. Pathological changes in the lung, the presence of MWCNT or asbestos, and fibrosis were noted at 40 and 80 µg MWCNT and in asbestos-exposed mice at 1 yr postexposure. To determine potential signaling pathways involved with MWCNT-associated pathological changes in comparison to asbestos, up- and down-regulated gene expression was determined in lung tissue at 1 yr postexposure. Exposure to MWCNT tended to favor those pathways involved in immune responses, specifically T-cell responses, whereas exposure to asbestos tended to favor pathways involved in oxygen species production, electron transport, and cancer. Data indicate that MWCNT are biopersistent in the lung and induce inflammatory and fibrotic pathological alterations similar to those of crocidolite asbestos, but may reach these endpoints by different mechanisms.
Project description:Pulmonary exposure to multiwalled carbon nanotubes (MWCNT) induces an inflammatory and rapid fibrotic response, although the long-term signaling mechanisms are unknown. The aim of this study was to examine the effects of 1, 10, 40, or 80 μg MWCNT administered by pharyngeal aspiration on bronchoalveolar lavage (BAL) fluid for polymorphonuclear cell (PMN) infiltration, lactate dehydrogenase (LDH) activity, and lung histopathology for inflammatory and fibrotic responses in mouse lungs 1 mo, 6 mo, and 1 yr postexposure. Further, a 120-μg crocidolite asbestos group was incorporated as a positive control for comparative purposes. Results showed that MWCNT increased BAL fluid LDH activity and PMN infiltration in a dose-dependent manner at all three postexposure times. Asbestos exposure elevated LDH activity at all 3 postexposure times and PMN infiltration at 1 mo and 6 mo postexposure. Pathological changes in the lung, the presence of MWCNT or asbestos, and fibrosis were noted at 40 and 80 μg MWCNT and in asbestos-exposed mice at 1 yr postexposure. To identify non-invasive miRNA biomarkers, miRNA profiling was performed in blood samples collected from MWCNT exposed mice.