DNA Repair Deficincies as a Biomarker for Treatment Response in Acute Myeloid Leukaemia

  • Clare Crean

Student thesis: Doctoral ThesisDoctor of Philosophy

Abstract

Acute Myeloid Leukemia is most commonly seen in people over the age of 65. Globally, there is an increasingly elderly population so the rate of incidence of AML is set to increase. The therapy landscape for AML has changed little over the past four decades. Cytarabine, first approved in 1969, is still the standard of care therapy for AML. There has only been modest improvements in surviavl rates during this time and there is currently no method of determining which patients will or will not respond to Cytarabine treatment. An assay, developed in 2014, used microarray data to determine which breast cancer patients had a DDRD and therefore would be more responsive to DNA damaging agents. This project hass assessed the potential of using the DDRD assay for AML patients. The assay was applied to publicly available microarray data of >600 AML patients who were classed as DDRD negative or DDRD positive. The assay was also applied to microarray data of a panel of myeloid cell lines to be used as in vitro models. Clonogenic assays, flow cytometry and immunofluorescence was used to assess the repair efficiency of the in vitro models. A pooled CRISPR screen and single cell sequencing ascertained which mutations may be driving the DDRD phenotype in patients. Kaplan Meier analysis showed the DDRD positive patienst survived significantly worse than the DDRD negative cohort. Whole exome sequencing identified mutations which were common in DDRD postive patients. CRISPR screening detected multiple genes which may be driving DDRD positivity. Immunofluorescent staining of DNA repair genes showed a clear repair deficiency in the DDRD positive cell lines, as the assay had predicted. Responses of the model cell lines to a range of chemotherapeutic agents in clonogenic assays can also be segregated based on DDRD score. These results together validate the accuracy of the DDRD score at assessing DNA damage repair deficiencies. Furthermore, they demonstrate the benefit of using the DDRD score to predict the response to chemotherapeutic agent prior to patient administration.
Date of AwardJul 2020
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SponsorsLeukaemia & Lymphoma NI
SupervisorKen Mills (Supervisor), Christopher Scott (Supervisor) & Kevin Prise (Supervisor)

Keywords

  • Acute Myeloid Leukaemia (AML)
  • biomarkers
  • cancer
  • DNA damage repair

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