Project description:This study presents statistical analyses of gene expression in 5, 10 and 15 day post-fertilization (dpf) embryos of the teleost Fundulus heteroclitus treated with control vehicle (DMSO) or a potent non-ortho-PCB (PCB-126; 3,3’,4,4’,5-pentachlorobiphenyl). The embryos were from two populations: a clean, reference population (SC, Scorton Creek, MA USA) and a polluted Superfund population (N, New Bedford Harbor, MA USA). For each site, eggs from 8 females (~1100 total) were fertilized using minced testes from 5 males. After non-fertile eggs were culled, embryos were exposed to vehicle (DMSO; 0.1%) or PCB-126 (50 nM) in filtered seawater (salinity 25 part per thousand, 65 embros per 20 ml in glass petri dish) for 4 hr at 20º C. After exposure, the embryos were washed in filtered seawater and incubated at 20º C under a 14-h light, 10-h dark cycle. At 5-, 10-, and 15-dpf, embryos were collected as three pools of 20 embryos from each treatment group and flash frozen in liquid nitrogen and stored at -80º C until used for RNA isolation.
Project description:This study presents statistical analyses of gene expression in 5, 10 and 15 day post-fertilization (dpf) embryos of the teleost Fundulus heteroclitus treated with control vehicle (DMSO) or a potent non-ortho-PCB (PCB-126; 3,3’,4,4’,5-pentachlorobiphenyl). The embryos were from two populations: a clean, reference population (SC, Scorton Creek, MA USA) and a polluted Superfund population (N, New Bedford Harbor, MA USA). For each site, eggs from 8 females (~1100 total) were fertilized using minced testes from 5 males. After non-fertile eggs were culled, embryos were exposed to vehicle (DMSO; 0.1%) or PCB-126 (50 nM) in filtered seawater (salinity 25 part per thousand, 65 embros per 20 ml in glass petri dish) for 4 hr at 20º C. After exposure, the embryos were washed in filtered seawater and incubated at 20º C under a 14-h light, 10-h dark cycle. At 5-, 10-, and 15-dpf, embryos were collected as three pools of 20 embryos from each treatment group and flash frozen in liquid nitrogen and stored at -80º C until used for RNA isolation. A loop design was used for the microarray hybridizations where each sample is hybridized to 2 arrays using both Cy3 and Cy5 labeled fluorophores. We used three loops in which each loop consisted of Cy3- and Cy5-labeled embryo aRNAs from 12 samples: one sample from each population-treatment-time combination. Within a population-treatment-time, embryos were randomly assigned to one of the three loops. In total, 36 embryos were hybridized to 36 microarrays. The loops formed were SC5C→ SC5P → NBH5C→ NBH5P →SC10C→ SC10P→ NBH10C→ NBH10P → SC15C→ SC15P → NBH15C → NBH15P → SC5C, where each arrow represents a separate hybridization (array) with the biological sample at the base of the arrow labeled with Cy3 and the biological sample at the head of the arrow labeled with Cy5. SC represents the Scorton Creek, Sandwich, MA population (reference), NBH represents the New Bedford Harbor, MA population, C represents control dose (DMSO), P represents the PCB-126 dose, 5 represents 5 dpf, 10 represents 10 dpf and 15 represents 15 dpf.
Project description:Although the tumor promoting effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), coplanar polychlorinated biphenyls (PCBs) and related compounds in liver tissue are primarily attributed to activation of the aryl hydrocarbon receptor (AhR), the underlying molecular mechanisms are still unclear. Liver progenitor (oval) cells have been suggested to constitute a potential target for hepatocarcinogenic chemicals. To better understand AhR-driven pathways we analyzed the transcriptional program in response to coplanar PCB 126 in rat liver progenitor WB-F344 cells using high density microarrays. After 6h treatment, we identified 145 significantly deregulated genes considered to be direct AhR-dependent target genes. The number of differentially regulated genes increased to 658 and 968 genes after 24h and 72h, respectively. Gene ontology analysis revealed that these genes were primarily involved in drug and lipid metabolism, cell cycle and growth control, cancer developmental processes, cell-cell communication and adhesion. Interestingly, the Wnt and TGF-beta signaling pathways, both being involved in developmental and tumorigenic processes, belonged to the most affected pathways. AhR and ARNT-dependent regulation of selected target genes of interest was then confirmed using TCDD as a model AhR agonist, together with pharmacological inhibition of the AhR and by RNA-interference techniques. We demonstrated AhR-dependent regulation of emerging and novel AhR target genes, such as Fst, Areg, Hbegf, Ctgf, Btg2, and Foxq1. Among them, the transcription factor Foxq1, recently suggested to contribute to tumor promotion and/or progression, was found to be regulated at both mRNA and protein levels by AhR/ARNT activation. 18 Total samples were analyzed (3 independent repeats for each treatment and time point). We generated the following pairwise comparisons: Control vs. PCB 126 at 6 h; Control vs. PCB 126 at 24 h; Control vs. PCB 126 at 72 h;
Project description:Two rat hepatic cell lines, WB-F344 and WB311, were characterized for the effect of rapamycin on gene expression. The WB311 cell line, which is tumorigenic and resistant to the growth inhibitory effects of rapamycin, was originally derived from the WB-F344 parental hepatic epithelial cell line. The goal of this experiment was to identify genes that responded to rapamycin in the sensitive cells but not the resistant cells, thereby providing insight into the mechanism of rapamycin resistance. Experiment Overall Design: Total RNA for each of four experimental groups was prepared and analyzed in triplicate: WB-F344, vehicle control; WB-F344, rapamycin; WB311, vehicle control; WB311, rapamycin.
Project description:Two rat hepatic cell lines, WB-F344 and WB311, were characterized for the effect of rapamycin on gene expression. The WB311 cell line, which is tumorigenic and resistant to the growth inhibitory effects of rapamycin, was originally derived from the WB-F344 parental hepatic epithelial cell line. The goal of this experiment was to identify genes that responded to rapamycin in the sensitive cells but not the resistant cells, thereby providing insight into the mechanism of rapamycin resistance.