Streamlining preclinical in vivo treatment trials by multiplexing genetically labelled PDX models in a single mouse

Better treatment options are intensively needed for acute leukemias. Before application in clinical trials, novel therapies require preclinical testing which is resource intensive. We established a patient derived xenograft (PDX) mouse model of ALL and AML, which allow serial transplantation in immunodeficient NSG mice. Up to 5 ALL or AML PDX samples were labelled with an individual genetic barcode and fluorochrome, then multiplexed and aliquots were injected into groups of mice (n=4-6). PDX Cells were reisolated from murine bone marrow and spleen and determining fluorochrome composition allowed quantifying the proportion that each of the 5 samples contributed to the entire tumor load. In a study using the BCL-2 inhibitor Venetoclax, we were able to distinguish between sensitive and resistant PDX samples. While two samples showed a drastic decrease in tumor burden, three samples showed no or only a mild response. Taken together, we established a multiplex protocol for in vivo therapy trials that allows simultaneous testing of up to 5 PDX samples in competitive in vivo trials. The approach reduced the required number of experimental mice by a factor 5, in line with the 3R concept.

Publication History

Article published online:
17 May 2022