Evolution of antibiotic resistance in microbes is frequently achieved by acquisition of spontaneous mutations during antimicrobial therapy. Here we demonstrate that inactivation of a central regulator of iron homeostasis (fur) facilitates laboratory evolution of ciprofloxacin resistance in Escherichia coli. To decipher the underlying molecular mechanisms, we first performed a global transcriptome analysis and demonstrated a substantial reorganization of the Fur regulon in response to antibiotic treatment. We hypothesized that the impact of Fur on evolvability under antibiotic pressure is due to the elevated intracellular concentration of free iron and the consequent enhancement of oxidative damage-induced mutagenesis. In agreement with expectations, over-expression of iron storage proteins, inhibition of iron transport, or anaerobic conditions drastically suppressed the evolution of resistance, while inhibition of the SOS response-mediated mutagenesis had no such effect in fur deficient population. In sum, our work revealed the central role of iron metabolism in de novo evolution of antibiotic resistance, a pattern that could influence the development of novel antimicrobial strategies.
Perturbation of iron homeostasis promotes the evolution of antibiotic resistance.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Cell-Cycle-Targeting MicroRNAs as Therapeutic Tools against Refractory Cancers.
Specimen part, Cell line
View SamplesCyclins and cyclin-dependent kinases (CDKs) are hyperactivated in nearly all human tumor types. To identify new approaches for interfering with cyclins/CDKs, we systematically searched for microRNAs (miRNAs) regulating these proteins. We uncovered a group of miRNAs that target nearly all cyclins and CDKs, and demonstrated that these miRNAs are very effective in shutting off cancer cell expansion. By profiling the response of over 120 human cancer cell lines representing 12 tumor types to these cell-cycle-targeting miRNAs, we identified miRNAs particularly effective against triple-negative breast cancers and KRAS-mutated cancers. We also derived expression-based algorithm that predicts response of primary tumors to cell-cycle-targeting miRNAs. Using systemic administration of nanoparticle-formulated miRNAs, we halted tumor progression in seven mouse xenograft models, including three highly aggressive and treatment-refractory patient-derived tumors, without affecting normal tissues. Our results highlight the utility of using cell-cycle-targeting miRNAs for treatment of refractory cancer types. Overall design: RNA-seq for SW900 cells transfected with 25 nM of miR-193a-3p mimic or 25 nM of negative miRNA control (Negative control #2, Ambion).
Cell-Cycle-Targeting MicroRNAs as Therapeutic Tools against Refractory Cancers.
No sample metadata fields
View SamplesCyclins and cyclin-dependent kinases (CDKs) are hyperactivated in nearly all human tumor types. To identify new approaches for interfering with cyclins/CDKs, we systematically searched for microRNAs (miRNAs) regulating these proteins. We uncovered a group of miRNAs that target nearly all cyclins and CDKs, and demonstrated that these miRNAs are very effective in shutting off cancer cell expansion. By profiling the response of over 120 human cancer cell lines representing 12 tumor types to these cell-cycle-targeting miRNAs, we identified miRNAs particularly effective against triple-negative breast cancers and KRAS-mutated cancers. We also derived expression-based algorithm that predicts response of primary tumors to cell-cycle-targeting miRNAs. Using systemic administration of nanoparticle-formulated miRNAs, we halted tumor progression in seven mouse xenograft models, including three highly aggressive and treatment-refractory patient-derived tumors, without affecting normal tissues. Our results highlight the utility of using cell-cycle-targeting miRNAs for treatment of refractory cancer types.
Cell-Cycle-Targeting MicroRNAs as Therapeutic Tools against Refractory Cancers.
Specimen part
View SamplesTo identify a prognostic gene signature accounting for the distinct clinical outcomes in ovarian cancer patients
A gene signature predicting for survival in suboptimally debulked patients with ovarian cancer.
Specimen part
View Samplescharacterize the molecular signature of PB-IMC in different stages of tumor development, thus possibly leading to a novel, sensitive and elegant approach for early cancer detection and surveillance. Overall design: Two types of cancer. For each type 4 groups (day 0, day 4, day 8, day 11), for each group 3 biological repeats
The transcriptional profile of circulating myeloid derived suppressor cells correlates with tumor development and progression in mouse.
Specimen part, Cell line, Subject
View SamplesHuntingtons disease (HD) is an incurable hereditary neurodegenerative disorder, which manifests itself as a loss of GABAergic medium spiny (GABA MS) neurons in the striatum and caused by an expansion of the CAG repeat in exon 1 of the huntingtin gene. There is no cure for HD, existing pharmaceutical can only relieve its symptoms. Here, induced pluripotent stem cells were established from patients with low CAG repeat expansion in the huntingtin gene, and were then efficiently differentiated into GABA MS-like neurons under defined culture conditions. Analysis of differentially expressed genes between Huntingtons disease and wild type iPSCs derived GABA MS-like neurons has been performed.
Manifestation of Huntington's disease pathology in human induced pluripotent stem cell-derived neurons.
Age, Specimen part
View SamplesLuteolysis of the corpus luteum (CL) during non-fertile cycles involves a cessation of progesterone (P4) synthesis (functional regression) and subsequent structural remodeling. The molecular processes responsible for initiation of luteal regression in the primate CL are poorly defined. Therefore, a genomic approach was utilized to systematically identify differentially expressed genes in the rhesus macaque CL during spontaneous luteolysis. CL were collected prior to (days 10-11 post-LH surge, mid-late [ML] stage) or during (days 14-16, late stage) functional regression. Based on P4 levels, late stage CL were subdivided into functional late (FL, serum P4 > 1.5 ng/ml) and functionally-regressed late (FRL, serum P4 < 0.5 ng/ml) groups (n=4 CL/group). Total RNA was isolated, labeled and hybridized to Affymetrix genome microarrays that contain elements representing the entire rhesus macaque transcriptome. With the ML stage serving as the baseline, there were 681 differentially expressed transcripts (>2-fold change; p< 0.05) that could be categorized into three primary patterns of expression: 1) increasing from ML through FRL, 2) decreasing from ML through FRL, and 3) increasing ML to FL, followed by a decrease in FRL. Ontology analysis revealed potential mechanisms and pathways associated with functional and/or structural regression of the macaque CL. Quantitative real-time PCR was used to validate microarray expression patterns of 13 genes with the results being consistent between the two methodologies. Protein levels were found to parallel mRNA profiles in 4 of 5 differentially expressed genes analyzed by Western blot. Thus, this database will facilitate the identification of mechanisms involved in primate luteal regression.
Dynamic changes in gene expression that occur during the period of spontaneous functional regression in the rhesus macaque corpus luteum.
Sex
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The long noncoding RNA RMST interacts with SOX2 to regulate neurogenesis.
Cell line, Treatment
View SamplesWe report that knockdown of the lncRNA RMST changes the gene expression profile of neural stem cells.
The long noncoding RNA RMST interacts with SOX2 to regulate neurogenesis.
Cell line
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