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Regulation of Gene Expression in Tumour Tissue
Kulda, Vlastimil ; Černý, Radim (advisor) ; Vachtenheim, Jiří (referee) ; Kleibl, Zdeněk (referee)
Deregulation of gene expression caused by genetic or epigenetic changes plays an important role in pathogenesis of cancer. The thesis is a commented collection of ten publications dealing with the molecular biology of tumours. The author has significantly contributed to all of them. All the articles contained in the thesis are linked to the topic of assessment of molecules involved in gene expression regulation (microRNAs) or DNA alterations that affect gene expression (promoter methylation, presence of a fusion gene). MicroRNAs are short single-stranded RNA molecules involved in posttranscriptional regulation of gene expression by triggering mRNA degradation or inhibiting translation. It is a basic mechanism with an impact on all cellular processes including the pathogenesis of various diseases. MicroRNAs can either act as oncogenes by decreasing the expression of tumour-suppressor genes or as tumour-suppressor genes by decreasing the expression of oncogenes. However, the network of microRNA - RNA interactions is much more complex. Our published results that are part of this thesis are focused on colorectal carcinoma (CRC), prostate cancer, head and neck squamous cell carcinoma (HNSCC), gastric cancer and non-small cell lung cancer (NSCLC). In patients with CRC, we demonstrated the prognostic...
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Regulation of Gene Expression in Tumour Tissue
Kulda, Vlastimil ; Černý, Radim (advisor) ; Vachtenheim, Jiří (referee) ; Kleibl, Zdeněk (referee)
Deregulation of gene expression caused by genetic or epigenetic changes plays an important role in pathogenesis of cancer. The thesis is a commented collection of ten publications dealing with the molecular biology of tumours. The author has significantly contributed to all of them. All the articles contained in the thesis are linked to the topic of assessment of molecules involved in gene expression regulation (microRNAs) or DNA alterations that affect gene expression (promoter methylation, presence of a fusion gene). MicroRNAs are short single-stranded RNA molecules involved in posttranscriptional regulation of gene expression by triggering mRNA degradation or inhibiting translation. It is a basic mechanism with an impact on all cellular processes including the pathogenesis of various diseases. MicroRNAs can either act as oncogenes by decreasing the expression of tumour-suppressor genes or as tumour-suppressor genes by decreasing the expression of oncogenes. However, the network of microRNA - RNA interactions is much more complex. Our published results that are part of this thesis are focused on colorectal carcinoma (CRC), prostate cancer, head and neck squamous cell carcinoma (HNSCC), gastric cancer and non-small cell lung cancer (NSCLC). In patients with CRC, we demonstrated the prognostic...
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Transcriptional regulation of differentiation of embryonal carcinoma and malignant melanoma cells: The Role of Proteins p21 (WAF1) and MITF
Šestáková, Blanka ; Vachtenheim, Jiří (advisor) ; Černý, Radim (referee) ; Pavel, Stan (referee)
Summary. F9 cells (embryonal carcinoma) can be induced to differentiate with retinoic acid and dibutyryl-cAMP into cells with a phenotype resembling parietal endoderm. We show that the levels of cyclin-dependent kinase inhibitor p21/WAF1/Cip1 (p21) protein and mRNA are dramatically elevated at the end of this differentiation. Clones of F9 cells stably expressing ectopic p21 revealed, upon differentiation, upregulated levels of mRNA for thrombomodulin, a parietal endoderm-specific marker. Furthermore, p21 activated the thrombomodulin promoter in transient reporter assays and the p21 mutant defective in binding to cyclin E was equally efficient in activation. The promoter activity in differentiated cells was reduced by cotransfection of p21-specific siRNA or antisense cDNA. Coexpression of p21 increased the activity of the GAL-p300(1-1303) fusion protein on the GAL sites-containing TM promoter, implying that p21 might act through a derepression of the p300 N-terminal-residing repression domain, thereby enhancing the p300 coactivator function. Whereas p21 was strictly nuclear in undifferentiated cells, a large proportion of differentiated cells had p21 localized also in the cytoplasm, a site associated with the antiapoptotic function of p21. As differentiation of F9 cells into parietal endoderm-like cells...
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