Accumulation of single-stranded DNA in tumour cells as a result of replicative stress

Kunze, Meike

dc.contributor.advisor	Dobbelstein, Matthias Prof. Dr.
dc.contributor.author	Kunze, Meike
dc.date.accessioned	2018-01-15T08:57:31Z
dc.date.available	2018-02-06T23:50:47Z
dc.date.issued	2018-01-15
dc.identifier.uri	http://hdl.handle.net/11858/00-1735-0000-002E-E31E-B
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-6680
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-6680
dc.language.iso	eng	de
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject.ddc	610	de
dc.title	Accumulation of single-stranded DNA in tumour cells as a result of replicative stress	de
dc.type	doctoralThesis	de
dc.contributor.referee	Dobbelstein, Matthias Prof. Dr.
dc.date.examination	2018-01-30
dc.description.abstracteng	Cells are constantly subjected to DNA damaging agents like reactive oxygen species, UV light or, in the case of cancer cells, chemotherapeutic drugs. All these agents can lead to replicative stress, meaning that the most sensitive part of the cell cycle, namely S phase where cells replicate their DNA, is compromised. Cells developed several mechanisms to respond to replicative stress. One of the most prominent is the stalling of replication forks. Stalled forks can either be rapidly stabilised and eventually restarted or they collapse, leaving behind unfinished sites of replication that later on need to be dealt with. The stalling of forks leads to the exposure of stretches of single-stranded DNA (ssDNA). In this study we use a new DNA staining method to detect these stretches of ssDNA and refine it for use in a high-content, semi-automated setup. With this method we then conduct a mini-screen including proteins known to be involved in the DNA damage response and identify two candidates that are investigated further. Knockdown of G2E3, an E3 ubiquitin ligase, together with gemcitabine treatment leads to much higher levels of ssDNA as a read-out for stalled replication forks and γ-H2AX, a well established marker of DNA damage. We further provide evidence that G2E3 is a novel regulator of ATR/Chk1 signalling as it inhibits the phosphorylation and hence activation of Chk1, one of the key kinases of the DNA damage response. Based on these results, G2E3 is a potential new drug target for sensitising cancer cells for chemotherapy. The second protein investigated is MK2, a kinase known to be involved in signalling following DNA damage. We show that inhibition of MK2 rescues the normally observed induction of stalled forks and γ-H2AX accumulation upon gemcitabine treatment defining it as a regulator of replication fork stalling during replicative stress.	de
dc.contributor.coReferee	Hahn, Heidi Prof. Dr.
dc.subject.eng	Molecular Oncology	de
dc.subject.eng	Cancer	de
dc.subject.eng	Replicative stress	de
dc.subject.eng	Chemosensitisation	de
dc.subject.eng	G2E3	de
dc.subject.eng	MK2	de
dc.subject.eng	Gemcitabine	de
dc.subject.eng	Chemotherapy	de
dc.identifier.urn	urn:nbn:de:gbv:7-11858/00-1735-0000-002E-E31E-B-8
dc.affiliation.institute	Medizinische Fakultät	de
dc.subject.gokfull	Medizin (PPN619874732)	de
dc.subject.gokfull	Biochemie / Physiologische Chemie / Pathobiochemie - Allgemein- und Gesamtdarstellungen (PPN619875313)	de
dc.subject.gokfull	Biologie (PPN619875151)	de
dc.subject.gokfull	Methoden und Techniken in der Medizin (PPN619875143)	de
dc.description.embargoed	2018-02-06
dc.identifier.ppn	1010908782

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