By Cédric Brice & Sarah Xercavins Based on the study of: Matouk, I. J. et al. The H19 non-coding RNA is essential for human tumor growth. PLoS ONE 2, e845 (2007)
Sup’Biotech Paris, Promotion 2010, Option R&D.
TABLE DES MATIÈRES
Introduction 1. Bibliographic Data
1.1. 1.2. 1.3. 1.4. 1.5. 1.6. Presentation of H19 gene H19 gene is located on thehuman chromosome 11 Role and function of H19 Expression of H19 gene H19: An oncogene H19 is expressed in many different cancers
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2. About the supporting article
2.1. Materials, Methods and Experiments
BioCancell, a company that develops a Patient Targeted Therapy Approach to cure cancers 21 The H19 technology is a breakthrough,but it is not as perfect as it sounds 22
Cancers are one of the major cause of death in developed countries, this is the reason why many pharmaceutical laboratories try to find a miracle drug that will be usable in as many cancers as possible.
We will see in this report that a company named BioCancell made a real breakthrough by using H19gene as an inducer for some-kind of “suicide gene”. H19 is the major subject of this report, we tried to give you as many informations about it as we could. You will see that siRNA targeting H19 is inhibiting tumor growth or synthesis.
You will also see that even if this treatment is greatly hopeful, we are still doubtful about its possible long-term side-effects, like fertility problem orimpossible wounds regeneration.
1. Presentation of H19 gene
The H19 gene encodes a 2.3-kb non-coding mRNA which is strongly expressed during embryogenesis. The maternally expression of H19 is an untranslated RNA that serves as a ribonuclear and it is accumulated in epithelial cells in almost 10 percent of breast cancers. This gene belongs to an imprinted cluster,conserved on mouse chromosome 7 and human chromosome 11p15.
Figure 1: Schematic representation of the H19 gene. The position of H19 ICR, number of CpG nucleotides analyzed for methylation status and position of primer set used for expression analysis are indicated. For methylation analysis of H19 ICR, two regions were studied: ICRCTCF 1–2 (574 bp) and ICRCTCF 3–4 (660 bp). The positions of theCpGs analyzed in each sequence are shown by lollipops (19 CpGs in ICRCTCF 1–2 and 23 CpGs in ICRCTCF 3–4, respectively). The four CTCF binding sites are depicted as grey boxes within the ICRCTCF 1–2 and ICRCTCF 3–4. For proximal part of H19 promoter (white box with PP), 8 CpGs were analyzed. For expression analysis, real time quantitative RT-PCR was performed using the Taqman technology with twoprimers (black arrows) chosen to encompass an intron (wedge indicates the exon-exon splice junctions) and a universal probe (white box).
H19 is maternally expressed and the neighboring Igf2 gene is transcribed from the paternal allele. These two genes are co-expressed in endoderm- and mesoderm-derived tissues during embryonic development, which suggests a common mechanism of regulation. Theregulatory elements (imprinted control region, CTCF insulation, different enhancer sequences, promoters of the two genes, matrix attachment regions) confer a differential chromatin architecture to the two parental alleles leading to reciprocal expression.
Figure 2: Silencers around Igf2 and H19. The Igf2 gene is expressed from the paternal and the H19 gene from the maternal chromosome. Bothgenes share enhancers located downstream of H19, with the mesoderm (M) enhancers further downstream than the endoderm (E) enhancers. On the paternal chromosome (a), Igf2 uses the enhancers and H19 is switched off, whereas on the maternal chromosome (b), H19 uses the enhancers and Igf2 is switched off. (Transcription from Igf2 and H19 is shown by arrows.) Two differentially methylated regions are...