Project description:Cross-platform target gene screening in colorectal cancer (CRC): we have compared 25 tumoural CRC biopsies against their normal counterpart in 30 hybridizations with a home-made cDNA array (CNIO oncochip) and 16 hybridisations with a custom oligoarray (Agilent Technologies).
Project description:The imaginal discs of Drosophila melanogaster, where most known Hedgehog (Hh) signaling target genes are expressed with a restricted pattern, offers an accessible model system for identifying novel targets of the Hh signaling pathway. In the wing discs, cells near the A/P compartment boundary (B: ptc+) receive the highest level of Hh stimulation, A cells (A: hh-) further from the border receive lower levels of stimulation, while P cells (P: hh+) do not respond to Hh. To identify target genes whose expression is controlled by Hh signaling activity, we performed a systematic comparison of gene expression profiles among the A cells (A: hh-), the A cells adjacent to the A/P compartment boundary (B: ptc+), and P cells (P: hh+) via microarray analysis.
Project description:Paracrine Hedgehog (Hh) signaling regulates growth and patterning in many Drosophila organs. We mapped chromatin binding sites for Cubitus interruptus (Ci), the transcription factor that mediates outputs of Hh signal transduction, and we analyzed transcription profiles of control and mutant embryos to identify genes that are regulated by Hh. Putative targets we identified include several Hh pathway components, most previously identified targets, and many targets that are novel. Analysis of expression patterns of pathway components and target genes gave evidence of autocrine Hh signaling in the optic primordium of the embryo. And, every Hh target we analyzed that is not a pathway component appeared to be regulated by Hh in a tissue-specific manner. We present evidence that Hh-dependent tissue specificity is dependent upon transcription factors that are Hh-independent, suggesting that “pre-patterns” of transcription factors partner with Ci to make Hh-dependent gene expression position-specific. We utilized the DamID method to identify regions of CiRep methylated genomic DNA in stage 10-11 Drosophila embryos.
Project description:Paracrine Hedgehog (Hh) signaling regulates growth and patterning in many Drosophila organs. We mapped chromatin binding sites for Cubitus interruptus (Ci), the transcription factor that mediates outputs of Hh signal transduction, and we analyzed transcription profiles of control and mutant embryos to identify genes that are regulated by Hh. Putative targets we identified include several Hh pathway components, most previously identified targets, and many targets that are novel. Analysis of expression patterns of pathway components and target genes gave evidence of autocrine Hh signaling in the optic primordium of the embryo. And, every Hh target we analyzed that is not a pathway component appeared to be regulated by Hh in a tissue-specific manner. We present evidence that Hh-dependent tissue specificity is dependent upon transcription factors that are Hh-independent, suggesting that “pre-patterns” of transcription factors partner with Ci to make Hh-dependent gene expression position-specific. We utilized the DamID method to identify regions of CiAct methylated genomic DNA in stage 10-11 Drosophila embryos.
Project description:We report Hedgehog signaling responsive genes with or without Esrrb in NI3T3 cells. Using Hh-responsive cells, we used RNA-Seq to find Hh responsive genes. In addition, we tested Esrrb's modification on Hh target genes' response.
Project description:Aberrant activation of Hedgehog (Hh) signaling pathway plays important roles in both oncogenesis and targeted therapy of many cancers. The clinical application of FDA-approved Hh-targeted Smoothened inhibitor (SMOi) drugs is hindered due to the emergence of various primary or acquired drug resistance, indicating the need of novel anti-Hh therapies. Our previous studies demonstrate that epigenetic/transcriptional targeted therapies represent a promising direction for anti-Hh drug development. In this study, we identified CDK9 and CDK12, two transcription elongation regulators, as novel therapeutic targets for antagonizing the aberrant Hh pathway and overcoming SMOi resistance. CDK9 inhibition and CDK12 inhibition exhibited similarly potent anti-Hh activities when treating various SMOi responsive or resistant Hh-driven tumor models as previously reported BET inhibition or CDK7 inhibition. We also utilized SHH-subtype medulloblastoma (SHH-MB) as the representative Hh-driven cancer model to perform Super-enhancer (SE) analysis and elucidate the crucial roles of SE in Hh-driven oncogenesis and above-mentioned anti-Hh epigenetic/transcriptional targeted therapies. Furthermore, we identified IRS1, encoding a critical component and cytoplasmic adaptor protein of the IGF pathway, as an oncogenic Hh-driven SE target gene and effective therapeutic target of multiple Hh-driven tumor models, including the SMOi-resistant ones. Collectively, our study demonstrates that the SE-driven transcriptional dependencies represent promising therapeutic vulnerabilities for suppressing the aberrant Hh pathway and overcoming the SMOi resistance. As CDK9 inhibitor and IRS inhibitor drugs have already entered human clinical trials for cancer treatment, our study provides comprehensive preclinical support for expanding their trials to Hh-driven cancers in near future.
Project description:The patterning of Drosophila retina occurs both very fast and with high precision. This process is driven by the dynamic changes in signalling activity of the conserved Hedgehog (Hh) pathway, which coordinates cell fate determination, cell cycle and tissue morphogenesis. Here we show that during Drosophila retinogenesis, the retinal determination gene dachshund (dac) is not only a target of the Hh signaling pathway, but is also a modulator of its activity. Using developmental genetics techniques, we demonstrate that dac enhances Hh signaling by promoting the accumulation of the Gli transcription factor Cubitus interruptus (Ci) parallel to or downstream of fused. In the absence of dac, all Hh-mediated events associated to the morphogenetic furrow are delayed. One of the consequences is that, posterior to the furrow, dac- cells cannot activate a Roadkill-Cullin3 negative feedback loop that attenuates Hh signaling and which is necessary for retinal cells to continue normal differentiation. Therefore, dac is part of an essential positive feedback loop in the Hh pathway, guaranteeing the speed and the accuracy of Drosophila retinogenesis.