Resistance of acute lymphoblastic leukemia (ALL) cells to chemotherapy, whether present at diagnosis or acquired during treatment, is a major cause of treatment failure. Primary ALL cells are accessible for drug sensitivity testing at the time of new diagnosis or at relapse, but there are major limitations with current methods for determining drug sensitivity ex vivo. Here, we describe a functional precision medicine method using a fluorescence imaging platform to test drug sensitivity profiles of primary ALL cells. Leukemia cells are co-cultured with mesenchymal stromal cells and tested with a panel of 40 anti-leukemia drugs to determine individual patterns of drug resistance and sensitivity (“pharmacotype”). This imaging-based pharmacotyping assay addresses the limitations of prior ex vivo drug sensitivity methods by automating data analysis to produce high-throughput data while requiring fewer cells and significantly decreasing the labor-intensive time required to conduct the assay. The integration of drug sensitivity data with genomic profiling provides a basis for rational genomics-guided precision medicine.
Key features
• Analysis of primary acute lymphoblastic leukemia (ALL) blasts obtained at diagnosis from bone marrow aspirate or peripheral blood.
• Experiments are performed ex vivo with mesenchymal stromal cell co-culture and require four days to complete.
• This fluorescence imaging–based protocol enhances previous ex vivo drug sensitivity assays and improves efficiency by requiring fewer primary cells while increasing the number of drugs tested to 40.
• It takes approximately 2–3 h for sample preparation and processing and a 1.5-hour imaging time.
Graphical overview
BM: bone marrow; PB: peripheral blood; ALL: acute lymphoblastic leukemia; MNCs: mononuclear cells, which include leukemia cells when present; MSCs: mesenchymal stromal cells; LC50: drug concentration that kills 50% of the leukemia cells