Introduction: Mammalian target of rapamycin (mTOR) represents a key downstream intermediate for a myriad of oncogenic receptor tyrosine kinases. In the case of the insulin-like growth factor (IGF) pathway, the mTOR complex (mTORC1) mediates IGF-1 receptor (IGF-1R)-induced estrogen receptor alpha (ERa) phosphorylation/activation and leads to increased proliferation and growth in breast cancer cells. As a result, the prevalence of mTOR inhibitors combined with hormonal therapy has increased in recent years. Conversely, activated mTORC1 provides negative feedback regulation of IGF signaling via insulin receptor substrate (IRS)-1/2 serine phosphorylation and subsequent proteasomal degradation. Thus, the IGF pathway may provide escape (e.g. de novo or acquired resistance) from mTORC1 inhibitors. It is therefore plausible that combined inhibition of mTORC1 and IGF-1R for select subsets of ER-positive breast cancer patients presents as a viable therapeutic option. Methods: Using hormone-sensitive breast cancer cells stably transfected with the aromatase gene (MCF-7/AC-1), works presented herein describe the in vitro and in vivo antitumor efficacy of the following compounds: dalotuzumab (DALO; “MK-0646”; anti-IGF-1R antibody), ridaforolimus (RIDA; “MK-8669”; mTORC1 small molecule inhibitor) and letrozole (“LET”, aromatase inhibitor). Results: With the exception of MK-0646, all single agent and combination treatment arms effectively inhibited xenograft tumor growth, albeit to varying degrees. Correlative tissue analyses revealed MK-0646 alone and in combination with LET induced insulin receptor alpha A (InsR-A) isoform upregulation (both mRNA and protein expression), thereby further supporting a triple therapy approach. Conclusion: These data provide preclinical rationalization towards the combined triple therapy of LET plus MK-0646 plus MK-8669 as an efficacious anti-tumor strategy for ER-positive breast tumors. Overall design: 46 samples, 28 days post treatment
Ridaforolimus (MK-8669) synergizes with Dalotuzumab (MK-0646) in hormone-sensitive breast cancer.
Cell line, Treatment, Subject, Time
View SamplesSkeletal muscle mitochondrial dysfunction is secondary to T2DM and can be improved by long-term regular exercise training
Physical activity is the key determinant of skeletal muscle mitochondrial function in type 2 diabetes.
Age
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Impact of human MLL/COMPASS and polycomb complexes on the DNA methylome.
Specimen part, Cell line
View SamplesThe association of DNA CpG methylation (or its absence) with occupancy of histone post translational modifications has hinted at an underlying crosstalk between histone marks and DNA methylation in patterning the human methylome, an idea supported by corresponding alterations to both histone marks and DNA methylation during malignant transformation. This study investigated the framework by which histone marks influence DNA methylation. Using RNAi in a human pluripotent embryonic carcinoma cell line we depleted essential components of the histone modifying complexes that establish the posttranslational modifications H3K4me3, H3K27me3, and H2AK119ub, and we assayed the impact of the subsequent loss of these marks on the DNA methylome. Absence of H2AK119ub resulted predominantly in hypomethylation across the genome. Removal of H3K4me3 or, surprisingly, H3K27me3 caused CpG island hypermethylation at a subset of loci. Intriguingly, many promoters were co-regulated by all three histone marks, becoming hypermethylated with loss of H3K4me3 or H3K27me3 and becoming hypomethylated with depletion of H2AK119ub, and many of these co-regulated loci were among those that are commonly, aberrantly hypermethylated in cancer.
Impact of human MLL/COMPASS and polycomb complexes on the DNA methylome.
Specimen part, Cell line
View SamplesWe have identified the transcription factor forkhead box protein F2 (Foxf2) to be upregulated in its expression during the EMT process and studied its functional contribution to EMT by siRNA-mediated knockdown in NMuMG cells treated for 4 days with TGFbeta followed by mRNA-sequencing. Our analysis revealed a dual role of Foxf2 during TGFbeta-induced EMT in promoting apoptosis while inducing cell junction breakdown and migration. Overall design: mRNA sequencing of NMuMG/E9 cells transfected with control siRNA or Foxf2 specific siRNA and treated with TGFbeta for 4 days
Foxf2 plays a dual role during transforming growth factor beta-induced epithelial to mesenchymal transition by promoting apoptosis yet enabling cell junction dissolution and migration.
Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Distinct and overlapping control of 5-methylcytosine and 5-hydroxymethylcytosine by the TET proteins in human cancer cells.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Nucleosome positioning changes during human embryonic stem cell differentiation.
Specimen part, Cell line
View SamplesThe TET family of dioxygenases catalyze conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), but their involvement in establishing normal 5mC patterns during mammalian development and their contributions to aberrant control of 5mC during cellular transformation remains largely unknown. We depleted TET1, TET2, and TET3 by siRNA in a pluripotent embryonic carcinoma cell model and examined the impact on genome-wide 5mC and 5hmC patterns. TET1 depletion yielded widespread reduction of 5hmC, while depletion of TET2 and TET3 reduced 5hmC at a subset of TET1 targets suggesting functional co-dependence. TET2 or TET3-depletion also caused increased 5hmC, suggesting they play a major role in 5hmC removal. All TETs prevent hypermethylation throughout the genome, a finding dramatically illustrated in CpG island shores, where TET depletion resulted in prolific hypermethylation. Surprisingly, TETs also promote methylation, as hypomethylation was associated with 5hmC reduction. TET function was highly specific to chromatin environment: 5hmC maintenance by all TETs occurred at polycomb-marked chromatin and genes expressed at moderate levels; 5hmC removal by TET2 is associated with highly transcribed genes enriched for H3K4me3 and H3K36me3. Importantly, genes prone to hypermethylation in cancer become depleted of 5hmC with TET deficiency, suggesting the TETs normally promote 5hmC at these loci, and all three TETs are required for 5hmC enrichment at enhancers, a condition necessary for expression of adjacent genes. These results provide novel insight into the division of labor among TET proteins and reveal an important connection of TET activity with chromatin landscape and gene expression.
Distinct and overlapping control of 5-methylcytosine and 5-hydroxymethylcytosine by the TET proteins in human cancer cells.
Specimen part, Cell line
View SamplesNucleosomes are the basic unit of chromatin. Nucleosome positioning (NP) plays a key role in transcriptional regulation and other biological processes. To better understand NP we used MNase-seq to investigate changes that occur as human embryonic stem cells (hESCs) transition to nascent mesoderm and then to smooth muscle cells (SMCs). Compared to differentiated cell derivatives, nucleosome occupancy at promoters and other notable genic sites, such as exon/intron junctions and adjacent regions, in hESCs shows a stronger correlation with transcript abundance and is less influenced by sequence content. Upon hESC differentiation, genes being silenced, but not genes being activated, display a substantial change in nucleosome occupancy at their promoters. Genome-wide, we detected a shift of NP to regions of higher G+C content as hESCs differentiate to SMCs. Notably, genomic regions with higher nucleosome occupancy harbor twice as many GC changes but fewer than half AT changes, compared to regions with lower nucleosome occupancy. Finally, our analysis indicates that the hESC genome is not rearranged and has a sequence mutation rate resembling normal human genomes. Our study reveals another unique feature of hESC chromatin, and sheds light on the relationship between nucleosome occupancy and sequence G+C content.
Nucleosome positioning changes during human embryonic stem cell differentiation.
Specimen part, Cell line
View SamplesThis study provides a comprehensive evaluation of changes in gene expression during treatment with Genistein in vitro.
Dose- and Time-Dependent Transcriptional Response of Ishikawa Cells Exposed to Genistein.
Treatment
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