Project description:Down-modulation or loss-of-function mutations of the Notch 1 and 2 genes are associated with development of squamous cell carcinoma (SCC), a very frequent and therapy-resilient malignancy in skin, head/neck (H/N), lung and other surface epithelia. In this context, surprisingly little is known on the role of CSL (RBP-Jk), key effector of canonical Notch signaling endowed with intrinsic transcription repressive function. CSL expression is decreased in upper epidermal layers and differentiating primary human keratinocytes (HKCs), while it is up-regulated in premalignant and malignant SCC lesions and SCC cell lines from skin, Head/Neck and lung. Increased CSL levels enhance proliferation and self-renewal potential of HKCs and SCC cells, while its silencing induces growth arrest and apoptosis. In vivo, SCC cells with increased CSL levels give rise to rapidly expanding tumors, while upon CSL silencing they form smaller and more differentiated tumors with enhanced inflammatory infiltrate. Global transcriptomic analysis of HKC and SCC cells plus/minus CSL silencing reveals major modulation of apoptotic, cell cycle and pro-inflammatory genes, with no significant association with Notch or keratinocyte differentiation gene signatures. KDM6B, a histone demethylase gene with highly context dependent functions, is a direct CSL negative target, with an inverse role of CSL in HKC and SCC self-renewal and tumorigenesis, with IL6 as a target of likely significance. CSL / KDM6B protein expression could be used as biomarkers of SCC development and novel indicators of cancer treatment.
Project description:Down-modulation or loss-of-function mutations of the Notch 1 and 2 genes are associated with development of squamous cell carcinoma (SCC), a very frequent and therapy-resilient malignancy in skin, head/neck (H/N), lung and other surface epithelia. In this context, surprisingly little is known on the role of CSL (RBP-Jk), key effector of canonical Notch signaling endowed with intrinsic transcription repressive function. CSL expression is decreased in upper epidermal layers and differentiating primary human keratinocytes (HKCs), while it is up-regulated in premalignant and malignant SCC lesions and SCC cell lines from skin, Head/Neck and lung. Increased CSL levels enhance proliferation and self-renewal potential of HKCs and SCC cells, while its silencing induces growth arrest and apoptosis. In vivo, SCC cells with increased CSL levels give rise to rapidly expanding tumors, while upon CSL silencing they form smaller and more differentiated tumors with enhanced inflammatory infiltrate. Global transcriptomic analysis of HKC and SCC cells plus/minus CSL silencing reveals major modulation of apoptotic, cell cycle and pro-inflammatory genes, with no significant association with Notch or keratinocyte differentiation gene signatures. KDM6B, a histone demethylase gene with highly context dependent functions, is a direct CSL negative target, with an inverse role of CSL in HKC and SCC self-renewal and tumorigenesis, with IL6 as a target of likely significance. CSL / KDM6B protein expression could be used as biomarkers of SCC development and novel indicators of cancer treatment.
Project description:RNA-sequencing (RNA-Seq) protocols and bioinformatic pipelines are designed to streamline downstream analyses on sequences believed to be the most important. Here, we have challenged this dogma by preserving ribosomal RNA (rRNA) in our samples and by lowering the minimal RNA size window of our small RNA-Seq analyses to 8 nt
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes