We explored the relationship between Myc activity and PI3K signaling in ESCs. Our data demonstrate that Myc and PI3K signaling function cooperatively for supporting pluripotent property of ESCs. Moreover, our data demonstrate that exposure of ESCs to 2i condition render both Myc and PI3K dispensable for preserving ESC status.
Functional compensation between Myc and PI3K signaling supports self-renewal of embryonic stem cells.
Sex, Specimen part
View SamplesHeart failure is a leading cause of mortality and morbidity in the developed world, partly because mammals lack the ability to regenerate heart tissue. Whether this is due to evolutionary loss of regenerative mechanisms present in other organisms or to an inability to activate such mechanisms is currently unclear. Here, we decipher mechanisms underlying heart regeneration in adult zebrafish and show that the molecular regulators of this response are conserved in mammals. We identified miR-99/100 and Let-7a/c, and their protein targets smarca5 and fntb, as critical regulators of cardiomyocyte dedifferentiation and heart regeneration in zebrafish. Although human and murine adult cardiomyocytes fail to elicit an endogenous regenerative response following myocardial infarction, we show that in vivo manipulation of this molecular machinery in mice results in cardiomyocyte dedifferentiation and improved heart functionality after injury. These data provide a proof-of-concept for identifying and activating conserved molecular programs to regenerate the damaged heart. Overall design: RNA-Seq expression profiles of rat cardiomyocytes after knockdown of miR-99/100 and Let-7 miRNAs
In vivo activation of a conserved microRNA program induces mammalian heart regeneration.
No sample metadata fields
View SamplesThe maternal tract plays a critical role in the success of early embryonic development providing an optimal environment for establishment and maintenance of pregnancy. Preparation of this environment requires an intimate dialogue between the embryo and her mother. To advance our understanding of the process by which a foreign blastocyst is accepted by the maternal endometrium and better address the clinical challenges of infertility and pregnancy failure, it is imperative to decipher this complex molecular dialogue. The objective of the present work is to define the local response(s) of the maternal tract towards the embryo during the earliest stages of pregnancy.
Early developing pig embryos mediate their own environment in the maternal tract.
Specimen part, Disease
View SamplesThe objective of the present study is to investigate if females have the ability to recognise X or Y chromosome bearing spermatozoa and present a different response to different spermatozoa.
The battle of the sexes starts in the oviduct: modulation of oviductal transcriptome by X and Y-bearing spermatozoa.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Establishment of human iPSC-based models for the study and targeting of glioma initiating cells.
Specimen part, Cell line, Treatment
View SamplesGliomas can originate upon transformation of adult Neural Progenitor Cells (NPCs) to Tumor Initiating Cells (TICs). Studies on human Glioma TICs (GTICs) have focused on the use of primary tumors from which GTICs could be isolated. Therefore investigations on the driver events underlying NPC transformation and human glioma initiation remain limited to the use of human embryonic material. Here we report on the development of strategies for the modeling of human gliomagenesis based on the use of human induced Pluripotent Stem Cells (hiPSCs). Transformation of hiPSC-derived NPCs (iNPCs) by defined genetic alterations led to the establishment of tractable human GTIC models suitable for studying the early steps of gliomagenesis as well as for screening studies. Dysregulation of PI3K, MAPK and p53 signaling in iNPCs led to the acquisition of functional GTIC properties. In vivo transplantation led to the formation of highly aggressive, infiltrative and heterogeneous tumors upon limited dilutions and secondary transplantation, faithfully recapitulating gliomagenesis. Metabolic modulation by chemical approaches compromised GTIC viability. Pilot screening of 101 anti-cancer compounds identified 3 molecules specifically targeting transformed iNPCs and primary GTICs. Together, our results demonstrate the potential of hiPSCs for the functional testing of putative driver mutations underlying human tumorigenesis and pave new avenues for the development of personalized cancer therapeutics.
Establishment of human iPSC-based models for the study and targeting of glioma initiating cells.
Specimen part, Cell line, Treatment
View SamplesCancer originates as the progressive accumulation of genetic mutations in proto-oncogenes and tumor suppressors. However, the early events underlying tumor initiation remain largely elusive, mostly due to the general lack of information regarding the cells-of-origin responsible for tumor formation as well as the precise impacts of genetic insults on tumor initiation in vivo. Here, we demonstrate that Sox2-positive (Sox2+) adult stem cells are responsible for epithelial squamous tumor formation. Conditional expression of oncogenic Kras (KrasG12D) and knockout of p53 (also known as Trp53) in Sox2+ cells quickly and specifically resulted in the formation of squamous tumors in the forestomach and esophagus. GFP-based lineage tracing experiments demonstrated that Sox2+ cells are the cells-of-origin of squamous tumors in the esophagus and forestomach. Of note, our data showed that p53 deletion alone did not suffice for tumor initiation. On the contrary, tumor initiation was observed upon KrasG12D activation whereas p53 deletion further contributed to the malignancy of the generated tumors, pointing out distinct roles for Kras activation and p53 deletion in squamous tumor formation and progression, to which a multihit carcinogenesis model can be applied. Global gene expression analysis revealed secreting factors upregulated in the generated tumors induced by oncogenic Kras, which contribute to tumor progression. Taken together, these results demonstrate that epithelial squamous tumors can specifically originate as a consequence of defined genetic mutations in a Sox2+ cell population and highlight the connections between proliferative stem cells and tumor development in vivo. Overall design: Expression profiling of mouse tissues with genetically induced tumors by RNA-Seq
Mutations in foregut SOX2<sup>+</sup> cells induce efficient proliferation via CXCR2 pathway.
No sample metadata fields
View SamplesRescuing the function of mutant p53 protein is an attractive cancer therapeutic strategy. Using the NCI anticancer drug screen data, we identified two compounds from the thiosemicarbazone family that manifest increased growth inhibitory activity in mutant p53 cells, particularly for the p53R175 mutant. Mechanistic studies reveal that NSC319726 restores WT structure and function to the p53R175 mutant. This compound kills p53R172H knock-in mice with extensive apoptosis and inhibits xenograft tumor growth in a 175-allele specific mutant p53 dependent manner. This activity depends upon the zinc ion chelating properties of the compound as well as redox changes. These data identify NSC319726 as a p53R175 mutant reactivator and as a lead compound for p53 targeted drug development.
Allele-specific p53 mutant reactivation.
Specimen part, Cell line, Treatment
View SamplesChemotherapy resistance presents a major hurdle for cancer treatment. We proposed to identify the molecular changes through which breast cancer cells evolve resistance to conventional treatment, here cisplatin, so targeted therapy can be developed. Candidate approach RNAi screening was combined with cisplatin treatment in order to identify molecular pathways conferring survival advantages. The screening identified ATP7A, a copper transport ATPase responsible for the intercellular movement and sequestering of cisplatin, as a therapeutic target. Copper chelation with tetrathiomolybdate (TM) targets ATP7A. TM in combination with cisplatin sensitized drug-resistant breast cancer cells. Allograft and xenograft models in aythymic mice treated with TM/cisplatin combination therapy inhibited tumor growth and increased survival compared with monotreated mice. Examination of the molecular effects of TM on cisplatin efficacy in drug-resistant tumors revealed reduced levels of APT7A, reduced cisplatin sequestering by ATP7A and increased nuclear availability of cisplatin. Further, we showed that TM treatment combined with cisplatin reduced the half-life of ATP7A in human breast cancer cell lines. This finding offered the potential to combat drug platinum-resistant tumors and sensitize patients to conventional breast cancer treatments by identifying and targeting resistant tumors unique molecular adaptations.
Ammonium tetrathiomolybdate treatment targets the copper transporter ATP7A and enhances sensitivity of breast cancer to cisplatin.
Cell line, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
miR-30e targets IGF2-regulated osteogenesis in bone marrow-derived mesenchymal stem cells, aortic smooth muscle cells, and ApoE-/- mice.
Specimen part, Treatment
View Samples