CHECKTWO

Projekt finansowany przez Narodowe Centrum Nauki w ramach konkursu „Opus – 21”.

Nowe czynniki regulujące punkty kontrolne cyklu komórkowego w odpowiedzi na uszkodzenia w DNA.

Nr projektu: UMO-2021/41/B/NZ1/03750
Wartość projektu: 1.954.440,00 PLN
Wartość dofinansowania: 1.954.440,00 PLN
Okres realizacji projektu: 01.03.2022 – 28.02.2025

Kierownik projektu: dr Michał Malewicz

Cellular DNA is under a constant threat of damage by a range of endogenous insults such as reactive oxygen species generated as by-products of oxidative metabolism or exogenous factors such as exposure to high-energy radiation. In order to preserve their genetic material cells have evolved a complex set of adaptive responses that are activated by DNA damage and collectively referred to as the DNA damage response (DDR). Activation of DDR involves coordinated initiation of DNA repair, changes to chromatin configuration, altered gene expression (at transcriptional, posttranscriptional and translational level), induction of programmed cell death and arrest in cell cycle progression (checkpoint induction). Dysregulation of any aspect of DDR is potentially catastrophic and it is well established that defective DDR is a strong driver of oncogenesis. Defects in cell cycle control after DNA damage are particularly problematic, as they can potentially lead to acute cell death or aneuploidy (when attempting mitosis with several double strand DNA breaks) thus threatening the genomic stability of the cell. There are several checkpoints that are induced at specific stages of the cell cycle in response to DNA damage: G1, intra-S and G2/M checkpoint. G1 checkpoint is of primary importance, as its function is to arrest the cell cycle in G1 preventing cells with damaged DNA from initiating replication. Thus, the G1 checkpoint, which functionally depends on p53 protein, prevents collisions between replication machinery and DNA lesions. Because p53 gene is inactivated in more than half of all human cancers these cells become dependent on other checkpoints to protect against genomic instability, primarily on G2/M checkpoint. Therefore, substantial effort had been devoted by pharmaceutical companies to develop effective and safe pharmacological G2/M checkpoint blockers by targeting various checkpoint effector proteins (mainly kinases). Importantly, identification of additional proteins and mechanisms governing G2/M checkpoint regulation would significantly improve our understanding of DDR and potentially open new opportunities for targeted treatments in oncology. We have recently identified two novel G2/M checkpoint regulatory proteins: LZIC and LYAR. Both factors are evolutionary conserved, however neither protein has a clearly assigned molecular function. Inactivation of LZIC in cultured cells leads to a leaky late G2/M checkpoint induction after irradiation, defective signal transduction from DNA damage to the cell cycle machinery and aneuploidy. Depletion of LYAR with siRNA results in normal execution of the late G2/M checkpoint but defective induction of the early ATM-dependent G2/M checkpoint. In this project proposal we aim to determine how LZIC and LYAR regulate the induction and maintenance of G2/M checkpoints at the molecular level. Furthermore, we will search for synthetic lethal interactions between LZIC/LYAR and other DDR pathways that can be utilised in oncology for development of new targeted therapies. Lastly, we will investigate the expression patterns of LZIC and LYAR in lung cancer, which is characterised by intrinsic genomic instability, assessing their usefulness as biomarkers in oncology. We anticipate that the experimental data obtained within this project will greatly expand our knowledge on mechanisms of physiological and pathological DDR as well as will aid in diagnostic and therapeutic efforts in oncology.