we evaluated the mechanism behind NOTCH activation in prostate cancer
Inhibition of Notch pathway arrests PTEN-deficient advanced prostate cancer by triggering p27-driven cellular senescence.
Specimen part
View SamplesFollowing androgen ablation therapy (AAT), the vast majority of prostate cancer patients develop treatment resistance with a median time of 18-24 months to disease progression. To identify molecular targets that aid in prostate cancer cell survival and contribute to the androgen independent phenotype, we evaluated changes in LNCaP cell gene expression during 12 months of androgen deprivation. At time points reflecting critical growth and phenotypic changes, we performed Affymetrix expression array analysis to examine the effects of androgen deprivation during the acute response, during the period of apparent quiescence, and during the emergence of highly proliferative, androgen-independent prostate cancer cells (LNCaP-AI). We discovered alterations in gene expression for a host of molecules associated with promoting prostate cancer cell growth and survival, regulating cell cycle progression, apoptosis and adrenal androgen metabolism, in addition to AR co-regulators and markers of neuroendocrine disease. These findings illustrate the complexity and unpredictable nature of cancer cell biology and contribute greatly to our understanding of how prostate cancer cells likely survive AAT. The value of this longitudinal approach lies in the ability to examine gene expression changes throughout the cellular response to androgen deprivation; it provides a more dynamic illustration of those genes which contribute to disease progression in addition to specific genes which constitute a malignant androgen-independent phenotype. In conclusion, it is of great importance that we employ new approaches, such as the one proposed here, to continue exploring the cellular mechanisms of therapy resistance and identify promising targets to improve cancer therapeutics.
Longitudinal analysis of androgen deprivation of prostate cancer cells identifies pathways to androgen independence.
No sample metadata fields
View SamplesMetabolism in cancer serves to provide energy and key biomolecules that sustain cell growth, a process that is frequently accompanied by decreased mitochondrial use of glucose. Importantly, metabolic intermediates including mitochondrial metabolites are central substrates for post-translational modifications at the core of cellular signalling and epigenetics. However, the molecular means that coordinate the use of mitochondrial metabolites for anabolism and nuclear protein modification are poorly understood. Here, we unexpectedly found that genetic and pharmacological inactivation of Pyruvate Dehydrogenase A1 (PDHA1), a subunit of pyruvate dehydrogenase complex (PDC) that regulates mitochondrial metabolism16 inhibits prostate cancer development in different mouse and human xenograft tumour models. Intriguingly, we found that lipid biosynthesis was strongly affected in prostate tumours upon PDC inactivation. Mechanistically, we found that nuclear PDC controls the expression of Sterol regulatory element-binding transcription factor (SREBF) target genes by mediating histone acetylation whereas mitochondrial PDC provides cytosolic citrate for lipid synthesis in a coordinated effort to sustain anabolism. In line with the oncogenic function of PDC in prostate cancer, we find that PDHA1 and the PDC activator, Pyruvate dehydrogenase phospatase 1 (PDP1), are frequently amplified and overexpressed at both gene and protein level in these tumours. Taken together, our findings demonstrate that both mitochondrial and nuclear PDC sustains prostate tumourigenesis by controlling lipid biosynthesis thereby pointing at this complex as a novel target for cancer therapy.
Compartmentalized activities of the pyruvate dehydrogenase complex sustain lipogenesis in prostate cancer.
No sample metadata fields
View SamplesWe have generated mouse models of real CMT1B mutations in the gene encoding for myelin protein zero (P0). One of these mutants, P0S63del is retained in the ER where it elicits an unfolded protein response (UPR). Genetic ablation of the UPR factor CHOP restores the motor capacity in S63del mice. We used microarray to decipher the molecular mechanism undelying the P0S63del neuropathy and the rescue in S63del/Chop null nerves.
Resetting translational homeostasis restores myelination in Charcot-Marie-Tooth disease type 1B mice.
Age, Specimen part
View SamplesTransdifferentiation of fibroblasts into induced Neuronal cells (iNs) by neuronal-specific transcription factors Brn2, Myt1l and Ascl1 is a paradigmatic example of inter-lineage conversion across epigenetically distant cells. Despite tremendous progress on the transcriptional hierarchy underlying transdifferentiation, the enablers of the concomitant epigenome resetting remain to be elucidated. Here we investigated the role of KMT2A and KMT2B, two histone H3 lysine 4 methylases with cardinal roles in development, through individual and combined inactivation. We found that Kmt2b, whose human homologue's mutations cause dystonia, is selectively required for iN conversion through the suppression of the alternative myocyte program and the induction of neuronal maturation genes. Overall design: In order to study the role of KMT2A and KMT2B during transdifferentiation, we employed conditional mouse strains carrying: i) the exon 2 of Kmt2a and/or Kmt2b flanked by LoxP sites; ii) the knock-in of the YFP-coding gene into one Rosa26 allele, downstream of a LoxP-flanked transcription termination cassette (STOP cassette); and iii) the gene coding for the tamoxifen-inducible version of Cre recombinase knocked into the second Rosa26 allele (Glaser et al., 2006; Kranz et al., 2010; Testa et al., 2004). MEFs were derived from Kmt2a (and/or Kmt2b)fl/fl Cre+ YFP+ embryos and from Kmt2a+/+Kmt2b+/+ Cre+ YFP+ or Kmt2afl/+ Cre+ YFP+ for Kmt2a conditional KO (cKO) as controls (Figure 1A), and were subjected to transdifferentiation. After 13 days of BAM treatment, cells were FACS sorted for PSA-NCAM expression, and the transcriptome of positive and negative cells were independently profiled.
KMT2B Is Selectively Required for Neuronal Transdifferentiation, and Its Loss Exposes Dystonia Candidate Genes.
Specimen part, Subject
View SamplesSREBF-1c is a transcription factor regulating fatty acid biosynthesis. We have charaterized the impact of the abcence of SREBF-1c on the development of peripheral neuropathy
Lack of sterol regulatory element binding factor-1c imposes glial Fatty Acid utilization leading to peripheral neuropathy.
Age
View SamplesSTAT5A and STAT5B proteins belong to the family of signal transducers and activators of transcription. They are encoded by 2 separate genes with 91% identity in their amino acid sequences. Despite their high degree of conservation, STAT5A and STAT5B exert non-redundant functions, resulting at least in part from differences in target gene activation. To better characterize the differential contribution of STAT5A and STAT5B in gene regulation, we performed single or double knock-down of STAT5A and STAT5B using small interfering RNA. Subsequent gene expression profiling and RT-qPCR analyses of IL-3-stimulated Ba/F3-beta cells led to the identification of putative novel STAT5 target genes. Chromatin immunoprecipitation assays analyzing the corresponding gene loci identified unusual STAT5 binding sites compared to conventional STAT5 responsive elements. Some of the STAT5 targets identified are upregulated in several human cancers, suggesting that they might represent potential oncogenes in STAT5-associated malignancies.
In vivo identification of novel STAT5 target genes.
No sample metadata fields
View SamplesAtGenExpress: A multinational coordinated effort to uncover the transcriptome of the multicellular model organism Arabidopsis thaliana
The AtGenExpress global stress expression data set: protocols, evaluation and model data analysis of UV-B light, drought and cold stress responses.
Specimen part
View SamplesAtGenExpress: A multinational coordinated effort to uncover the transcriptome of the multicellular model organism Arabidopsis thaliana.
The AtGenExpress global stress expression data set: protocols, evaluation and model data analysis of UV-B light, drought and cold stress responses.
Specimen part
View SamplesAtGenExpress: A multinational coordinated effort to uncover the transcriptome of the multicellular model organism Arabidopsis thaliana.
The AtGenExpress global stress expression data set: protocols, evaluation and model data analysis of UV-B light, drought and cold stress responses.
Specimen part
View Samples