Section 2: Generating acquired resistance to BH3 mimetics in AML PDX models

Timing: variable by PDX model and drug

Begin continuous treatment of leukemia-bearing mice with BH3 mimetics until leukemia blasts relapse, indicating acquired drug resistance.

Pause point: Time to develop acquired resistance depends on PDX model and individual drug. For BH3 mimetics, we typically observed resistance developing between 45–120 days on treatment, denoted by >70% circulating peripheral blast counts or signs of disease progression in the mice.

Repeat section 1 step 5 to perform leukemia transplantation with murine spleen cells (Passage 2).

Note: We utilized splenic cells to perform serial transplantation because the spleens typically yielded a higher number of cells compared to the bone marrow.

Bleed the mice weekly with section 1 steps 6 and 7 to assess for circulating peripheral blasts.

Continue to bleed the mice weekly to assess for circulating peripheral blasts. Troubleshooting 2

When FACS analysis reveals >70% circulating peripheral blasts, sacrifice the mice and harvest bones and spleen following section 1 steps 8a-c.

Proceed to dynamic BH3 profiling. Troubleshooting 3