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Investigating the Mechanism of Action of DNA Damage Response Inhibitors

Pasetto, Martina (2023) MOBM02 20231
Degree Projects in Molecular Biology
Popular Abstract
Investigating the Mechanism of Action of DNA Damage Response Inhibitors

Cancer is a complex, heterogenous, systemic disease. It is considered to be a leading cause of death worldwide. Currently, there is limited treatment for this disease and the field of oncology presents the highest percentage of failed trials (32%) for drugs in phase II and phase III, mainly due to lack of efficacy or safety. The high complexity and heterogeneity of cancer are suspected to compromise treatment responses, causing patients with the same tumor to respond differently to the same treatments. Consequently, novel biomarkers to predict which patients will most likely benefit from specific treatments are needed. Even though genetics has been the main focus to... (More)
Investigating the Mechanism of Action of DNA Damage Response Inhibitors

Cancer is a complex, heterogenous, systemic disease. It is considered to be a leading cause of death worldwide. Currently, there is limited treatment for this disease and the field of oncology presents the highest percentage of failed trials (32%) for drugs in phase II and phase III, mainly due to lack of efficacy or safety. The high complexity and heterogeneity of cancer are suspected to compromise treatment responses, causing patients with the same tumor to respond differently to the same treatments. Consequently, novel biomarkers to predict which patients will most likely benefit from specific treatments are needed. Even though genetics has been the main focus to investigate predictive biomarkers, only for a few cancer types, genomic biomarkers have been found to be useful in the clinic. Therefore, novel approaches focused on protein signaling could be used to improve drug response, since many tumor cells are highly dependent on DNA damage response (DDR) pathways. This study aims to investigate the mechanism of action of DDR inhibitors. The dual CHK1 and CHK2 inhibitor, the PKMYT1 inhibitor and the Wee1 inhibitor were chosen as drugs.

The effect of the dual CHK1 and CHK2 inhibitor on cell cycle was investigated in both ovarian sensitive and resistant cell lines. While the drug did not show any effect on the cell cycle of non-sensitive cells, cell cycle arrest in intra-S phase together with an increased apoptosis could be observed in sensitive cells. These findings reflected the increase in frequency of replication forks collapse during the replicative phase of the cell cycle, which causes unregulated cell cycle progression, premature entry of cells with under-replicated genome into mitosis and cell death. Drug sensitivity studies showed PKMYT1 inhibitor to be highly potent in brain cancer. Furthermore, target engagement and a downregulation of the inhibitory T14 phosphorylation on CDK1 was verified via western blotting. The mechanism of action of the Wee1 inhibitor was investigated using drug sensitivity testing, western blotting and the EdU proliferative assay. Renal adenocarcinoma cells were found to be highly sensitive to the Wee1 inhibitor, whereas breast cancer cells were found to be resistant. The drug was found to remove the inhibitory Y15 phosphorylation from CDK1, while increasing DNA damage and causing cell cycle progression. These results suggested that the Wee1 inhibitor causes premature entry of cells into mitosis and mitotic catastrophe.

Overall, the ability of unstable cancer cells to avoid mitotic catastrophe is believed to promote uncontrollable cell growth. Consequently, using the dual CHK1 and CHK2 inhibitor, PKMYT1 inhibitor and Wee1 inhibitor to induce mitotic catastrophe could be promising to improve treatment outcomes.

Master’s Degree Project in Molecular Biology, 30 credits, 2023
Department of Biology, Lund University

Advisors: Valentina Siino, Uthira Muralitharan, Olivier Van Aken
Acrivon Therapeutics (Less)
Please use this url to cite or link to this publication:
author
Pasetto, Martina
supervisor
organization
course
MOBM02 20231
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
9136016
date added to LUP
2023-09-01 14:39:10
date last changed
2023-09-01 14:39:10
@misc{9136016,
  author       = {{Pasetto, Martina}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Investigating the Mechanism of Action of DNA Damage Response Inhibitors}},
  year         = {{2023}},
}