Establishing multiplex in vivo assays in a xenograft mouse model of acute leukaemia to correlate preclinical treatment trials with molecular screens

Hunt, Katharina (2023): Establishing multiplex in vivo assays in a xenograft mouse model of acute leukaemia to correlate preclinical treatment trials with molecular screens. Dissertation, LMU München: Faculty of Veterinary Medicine

Abstract

Acute leukaemia is a rare disease, but the number of cases reported each year is steadily increasing. Standard therapy includes classical chemotherapy, which most patients respond to at the beginning. However, a major problem is relapse, which is associated with a poorer prognosis, so better treatment options are urgently needed. With advances in sequencing technology, more and more molecular features can be identified. As a result, patients benefit from more specific diagnostics and can be matched to potential specific treatment options. The number of targeted inhibitors has been increasing for years, and while there are many drugs existing, the biomarker to link the needed drug to the patient is not yet available. In the present study, the results of molecular dropout screens were used as a basis. The aim of the present study was to test the effect of selected targeted therapies against five PDX ALL models with different molecular alterations. Specific inhibitors were used to determine whether the molecular screen could predict a response to an inhibitor and results were correlated with the existing data from molecular screens. In order to preclinically test novel therapies, this work aimed to increase the efficiency of preclinical therapy trials. I was able to establish a multiplex protocol for in vivo treatment trials, allowing up to five ALL-PDX samples to be tested simultaneously in competitive in vivo trials. Flow cytometry was used to detect individual samples and investigate response towards targeting drugs. With this method, I was able to test three targeted therapies in vivo, while reducing the required number of mice by a factor of five, in line with the 3R concept. Detected dependencies in vivo were BCL2, MCL1 and XPO1. The correlation of in vivo therapy trials with the molecular functional results was high, with a positive correlation in three of five samples for all tested target / drug pairs, one sample with two positive correlations, and only one sample with no correlation between the two independent approaches. However, the PDX samples responded differently to the specific inhibitors, which highlights the concept of personalised medicine. Furthermore, the results state that the screen overestimates the efficacy of the drug.

• Item Type: Theses (Dissertation, LMU Munich)
• Subjects: 500 Natural sciences and mathematics; 500 Natural sciences and mathematics > 590 Zoological sciences
• Faculties: Faculty of Veterinary Medicine
• Language: English
• Date of oral examination: 22. July 2023
• 1. Referee: Wolf, Eckhard
• Signature of the printed copy: 0001/UMC 30649