Medizinische Universität Graz - Research portal
Selected Publication:
Neuboeck, S.
Establishing and Characterizing Isogenic AML Cell Lines to Study the Role of TP53 Dysfunction in Therapeutic Resistance.
[ Diplomarbeit/Master Thesis (UNI) ] Technische Universität Graz; 2021. pp.104.
FullText
- Authors Med Uni Graz:
- Advisor:
- Dutta Sayantanee
- Sill Heinz
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- Abstract:
- Transcription factor p53 is encoded by tumor suppressor gene TP53 which is involved in cellular response to pathogenic stimuli like oxidative stress, DNA damage by controlling cell cycle and apoptosis. In about 50% of human malignancies disruption, dysfunction, or loss of TP53 gene is encountered. Germline mutations in TP53 gene causes Li-Fraumeni syndrome predisposing individuals to higher chances of developing several malignancies like breast cancer, sarcoma, lymphoma and leukemia. TP53 is one of the most frequently mutated genes in premalignant hematopoietic progenitors of healthy individuals with clonal hematopoiesis of indeterminate potential (CHIP). In contrast to solid tumors, TP53 mutations occur only in 8-20% of the cases of newly diagnosed acute myeloid leukemia (AML), however disruption or loss of TP53 is an independent risk factor for poor outcome in AML. Resistance to chemotherapeutic agents occurs with a higher incidence in AML patients with TP53 dysfunctions or mutations, therefore deciphering the role of TP53 in chemotherapeutic resistance remains a great demand for novel and alternative treatment strategies in AML. Based on the fundamental knowledge on physiology and pathology of TP53 we propose, that the loss of TP53 function can offer cancer cells, mechanisms to avoid apoptosis and cell cycle arrest while becoming more resistant to DNA damage, ending in the development of cells that can resist chemotherapy. To prove our hypothesis, we generated isogenic TP53 deficient AML cell lines in OCI AML5 cells by utilizing a CRISPR-Cas9 mediated genome engineering. We retrieved heterozygous and homozygous TP53 knockout cell lines and TP53 dysfunctional cell lines that expressed a non-functional protein. We have evaluated the impact of cytostatic stress on viability and apoptosis of TP53 aberrant cells under the treatment of two drugs that are used routinely as conventional chemotherapy treatment for AML, Daunorubicin (DNR) and Cytarabine (AraC). We could see a higher viability and lower apoptosis of the TP53 deficient cell lines under drug treatment in comparison to the native OCI AML5 cell line with wild type TP53 status (TP53+/+). These results confirm experimentally that loss or dysfunction of TP53 can lead to chemoresistance. Here, we have successfully established a drug-resistant isogenic AML cell line model of TP53 loss and dysfunction which can be used to decipher the mode by which TP53 confers drug resistance.