The study of the factors affecting colorectal cancer chemotherapy

Application of cytotoxic chemotherapy still remains the essential treatment strategy in advanced colorectal cancer. The intrinsic and acquired drug resistance represents one of the reasons that may even lead to failure of cancer therapy. The DNA damage response pathways have been shown to play an important role in the development of chemoresistance. There is sufficient evidence showing the high-frequency deregulated expression of many DNA repair genes across multiple cancer types. An example of such gene in colorectal cancer is MRE11, which encodes protein known as a sensor of DNA double-strand breaks. In year 2016, there was a substantial study published by our group at The Department of Molecular Biology of Cancer (IEM CAS, Prague), the study analysed the association of polymorphisms in predicted microRNA target sites of double-strand breaks (DSBs) repair genes, including MRE11, and clinical outcome and efficacy of chemotherapy in colorectal cancer. Our hypothesis, based on the mentioned study, is that specifically and exactly defined microRNAs with ability to regulate certain DNA repair proteins may not only affect the survival of colorectal cancer cells, but also the sensitivity to chemotherapy. In practical part of the submitted thesis we have identified miR-140 as a potential regulator of..

Faktory ovlivňující odpověď kolorektálního karcinomu na chemoterapeutickou léčbu

Aplikace cytotoxické chemoterapie nadále představuje základní strategii v léčbě pokročilých stádiích kolorektálního karcinomu. Přirozená či získaná rezistence nádoru představuje častou komplikaci chemoterapie nebo vede dokonce k jejímu selhání. Ukazuje se, že úlohu v terapeutické rezistenci nádorů sehrávají kromě jiného i dráhy zodpovědné za opravu poškozené DNA. Pozorování u řady nádorů odhalily vysokou frekvenci deregulované exprese u mnoha genů, které kódují DNA reparační proteiny. Příkladem takového proteinu u kolorektálního karcinomu je MRE11, senzorický protein dvouřetězcových zlomů DNA. Na Oddělení molekulární biologie nádorů (ÚEM AV ČR, v. v. i.) byla roku 2016 publikována studie, která pojednává o vztahu genetických polymorfismů v místech vazby microRNA na mRNA reparačních proteinů, mezi nimi i MRE11, klinickým výstupem a úspěšností chemoterapie. Na základě těchto výsledků byla vypracována hypotéza, že konkrétně definované microRNA, které budou asociovat s mRNA reparačních proteinů, umožní nejen ovlivnit přežívání kolorektálních nádorových buněk, ale i citlivost vůči aplikované chemoterapii. V praktické části předložené práce jsme pomocí in silico analýzy identifikovali miR-140 jako potencionální regulátor proteinu MRE11. Následně byl v in vitro funkčních analýzách testovaný vliv miR-140...Application of cytotoxic chemotherapy still remains the essential treatment strategy in advanced colorectal cancer. The intrinsic and acquired drug resistance represents one of the reasons that may even lead to failure of cancer therapy. The DNA damage response pathways have been shown to play an important role in the development of chemoresistance. There is sufficient evidence showing the high-frequency deregulated expression of many DNA repair genes across multiple cancer types. An example of such gene in colorectal cancer is MRE11, which encodes protein known as a sensor of DNA double-strand breaks. In year 2016, there was a substantial study published by our group at The Department of Molecular Biology of Cancer (IEM CAS, Prague), the study analysed the association of polymorphisms in predicted microRNA target sites of double-strand breaks (DSBs) repair genes, including MRE11, and clinical outcome and efficacy of chemotherapy in colorectal cancer. Our hypothesis, based on the mentioned study, is that specifically and exactly defined microRNAs with ability to regulate certain DNA repair proteins may not only affect the survival of colorectal cancer cells, but also the sensitivity to chemotherapy. In practical part of the submitted thesis we have identified miR-140 as a potential regulator of...Department of Genetics and MicrobiologyKatedra genetiky a mikrobiologiePřírodovědecká fakultaFaculty of Scienc

Synthesis and Structural Optimization of 2,7,9-Trisubstituted purin-8-ones as FLT3-ITD Inhibitors

Therapy of FLT3-positive acute myeloid leukemia still remains complicated, despite the availability of newly approved kinase inhibitors. Various strategies to avoid the reduced efficacy of therapy have been explored, including the development of dual targeting compounds, which inhibit FLT3 and another kinase necessary for the survival and proliferation of AML cells. We have designed new 2,7,9-trisubstituted 8-oxopurines as FLT3 inhibitors and report here the structure-activity relationship studies. We demonstrated that substituents at positions 7 and 9 modulate activity between CDK4 and FLT3 kinase, and the isopropyl group at position 7 substantially increased the selectivity toward FLT3 kinase, which led to the discovery of compound 15a (9-cyclopentyl-7-isopropyl-2-((4-(piperazin-1-yl)phenyl)amino)-7,9-dihydro-8H-purin-8-one). Cellular analyses in MV4-11 cells revealed inhibition of autophosphorylation of FLT3 kinase in nanomolar doses, including the suppression of downstream STAT5 and ERK1/2 phosphorylation. We also describe mechanistic studies in cell lines and activity in a mouse xenograft model in vivo