Molekulární prognostické a prediktivní markery u kolorektálního karcinomu

in English Colorectal cancer is currently one of the three major causes of cancer-related death. In order to help clinicians to treat colorectal cancer, it is necessary to introduce more effective tools that will improve not only early diagnosis, but also prediction of the most likely progression of the disease and response to chemotherapy. This thesis aims to describe the most accepted biomarkers among those proposed for use in CRC divided based on the clinical specimen that is examined (tissue, feces or blood) along with their restrictions. In relation to my research, the thesis will also focus on alternative splicing that has emerged as an important regulator and potential treatment target in CRC. Alterations in gene expression leading to colorectal carcinogenesis results in dysregulated levels of nucleic acids and proteins, which can be utilized for the identification of modern, minimally invasive molecular biomarkers. One of the alternative splicing factors are MBNL proteins. The goal of my work that will be presented here was to analyze gene expression of the MBNL family of regulators of alternative splicing in various stages of colorectal cancer development, together with the MBNL-target splicing events in FOXP1 and EPB41L3 genes and tumor-related CD44 variants. The study was done using...in Czech Kolorektální karcinom je v současné době jednou ze tří hlavních příčin úmrtí souvisejících s nádorovými onemocněními. Aby se klinickým lékařům pomohlo léčit kolorektální karcinom, je nutné zavést účinnější nástroje, které zlepší nejen včasnou diagnostiku, ale také predikci nejpravděpodobnější progrese onemocnění a reakce na chemoterapii. Tato práce si klade za cíl popsat nejpřijatelnější biomarkery mezi těmi, které jsou navrženy pro použití v CRC, rozdělené podle klinického vzorku, který je vyšetřován (tkáň, stolice nebo krev), spolu s jejich omezeními. Ve vztahu k mému výzkumu se práce zaměří také na alternativní sestřih, který se ukázal jako důležitý regulátor a potenciální cíl léčby v CRC. Změny v genové expresi vedoucí ke kolorektální karcinogenezi vedou k dysregulovaným hladinám nukleových kyselin a proteinů, které lze využít k identifikaci moderních, minimálně invazivních molekulárních biomarkerů. Jedním z alternativních spojovacích faktorů jsou MBNL proteiny. Cílem mé práce, která zde bude představena, byla analýza genové exprese rodiny MBNL regulátorů alternativního sestřihu v různých fázích vývoje kolorektálního karcinomu, spolu s událostmi sestřihu cíle MBNL v genech FOXP1 a EPB41L3 a CD44 souvisejícími s nádorem varianty. Studie byla provedena pomocí vzorků nádorové tkáně a...Ústav histologie a embryologieFaculty of Medicine in PilsenLékařská fakulta v Plzn

Molecular Prognostic and Predictive Markers in Colorectal Cancer

in English Colorectal cancer is currently one of the three major causes of cancer-related death. In order to help clinicians to treat colorectal cancer, it is necessary to introduce more effective tools that will improve not only early diagnosis, but also prediction of the most likely progression of the disease and response to chemotherapy. This thesis aims to describe the most accepted biomarkers among those proposed for use in CRC divided based on the clinical specimen that is examined (tissue, feces or blood) along with their restrictions. In relation to my research, the thesis will also focus on alternative splicing that has emerged as an important regulator and potential treatment target in CRC. Alterations in gene expression leading to colorectal carcinogenesis results in dysregulated levels of nucleic acids and proteins, which can be utilized for the identification of modern, minimally invasive molecular biomarkers. One of the alternative splicing factors are MBNL proteins. The goal of my work that will be presented here was to analyze gene expression of the MBNL family of regulators of alternative splicing in various stages of colorectal cancer development, together with the MBNL-target splicing events in FOXP1 and EPB41L3 genes and tumor-related CD44 variants. The study was done using..

Oxidative Damage in Sporadic Colorectal Cancer: Molecular Mapping of Base Excision Repair Glycosylases MUTYH and hOGG1 in Colorectal Cancer Patients

Oxidative stress, oxidative DNA damage and resulting mutations play a role in colorectal carcinogenesis. Impaired equilibrium between DNA damage formation, antioxidant status, and DNA repair capacity is responsible for the accumulation of genetic mutations and genomic instability. The lesion-specific DNA glycosylases, e.g., hOGG1 and MUTYH, initiate the repair of oxidative DNA damage. Hereditary syndromes (MUTYH-associated polyposis, NTHL1-associated tumor syndrome) with germline mutations causing a loss-of-function in base excision repair glycosylases, serve as straight forward evidence on the role of oxidative DNA damage and its repair. Altered or inhibited function of above glycosylases result in an accumulation of oxidative DNA damage and contribute to the adenoma-adenocarcinoma transition. Oxidative DNA damage, unless repaired, often gives rise G:C > T:A mutations in tumor suppressor genes and proto-oncogenes with subsequent occurrence of chromosomal copy-neutral loss of heterozygosity. For instance, G>T transversions in position c.34 of a KRAS gene serves as a pre-screening tool for MUTYH-associated polyposis diagnosis. Since sporadic colorectal cancer represents more complex and heterogenous disease, the situation is more complicated. In the present study we focused on the roles of base excision repair glycosylases (hOGG1, MUTYH) in colorectal cancer patients by investigating tumor and adjacent mucosa tissues. Although we found downregulation of both glycosylases and significantly lower expression of hOGG1 in tumor tissues, accompanied with G>T mutations in KRAS gene, oxidative DNA damage and its repair cannot solely explain the onset of sporadic colorectal cancer. In this respect, other factors (especially microenvironment) per se or in combination with oxidative DNA damage warrant further attention. Base excision repair characteristics determined in colorectal cancer tissues and their association with disease prognosis have been discussed as well