Generation of an Isogenic Cell Line Model to Test Novel Treatment Options for TP53-Mutant AML

Abstract

Acute myeloid leukemia (AML) is a clonal malignancy of cellular elements in the myeloid lineage and is characterized by aberrant proliferation of myeloid blasts in the peripheral blood, bone marrow, or both. Despite improvements in the rate of long-term survival, some patients have an especially dismal prognosis, which can often be attributed to mutations found in the TP53 gene. P53 is a protein that functions as a transcriptional activator that induces cellular processes such as cell cycle arrest and apoptosis, in response to oncogenic hyperproliferation, DNA damage, and other cellular stress signals. Due to its important role in suppressing tumor formation, TP53 is mutated in 50% of all human cancers. There are several TP53 hotspot missense mutations that account for 75% of cases and lead to acquired novel oncogenic properties. We used CRISPR/Cas9-mediated homology-directing repair (CRISPR-HDR) to introduce these recurrent hotspot TP53 missense mutations in this gene and generate TP53 isogenic AML cell lines with wild-type TP53 and specific missense TP53 mutations. Given the importance of p53, we posit that a number of the functional characteristics of these cells will be affected. This model allows us to functionally and phenotypically characterize the cells and to test a selection of chemotherapeutic agents for their activity against TP53mutant AML. Our use of isogenic cell lines will enable identification of lethal interaction in TP53-mutated AML, with an unprecedented sensitivity. This understanding holds promise for discovering potential drug targets that will improve targeted therapy, and consequently the prognosis, for patients with TP53 mutant AML.