Polyethylene glycol 400

Animal experiments were performed in accordance with a protocol approved
by the Institutional Animal Care and Use Committee at MD Anderson. PDX cells (2
× 10⁶) were injected via tail vein into 40 male (16–20
or 5–9 wk) NSGS mice (Jackson Laboratory, Bar Harbor, ME). Engraftment
was confirmed by flow cytometry measuring human CD45⁺ cells
(anti-human CD45 antibody, BD Biosciences) (average 1%) in mouse peripheral
blood (PB). The mice were treated with vehicle only, VS-4718 twice daily (75
mg/kg) (8 ), ABT-199 daily (100 or 50
mg/kg), or the combination via oral gavage (n = 10/group) for 29 or 27 d.
VS-4718 was suspended in 5% sucrose. ABT-199 was dissolved in 60% PHOSAL 50PG
(LIPOID, Germany), 30% polyethylene glycol 400 (Spectrum Chemical, Gardena, CA),
and 10% 200-proof ethyl alcohol (Pharmco-Aaper, Brookfield, CT).
The leukemia progression was monitored weekly by flow cytometric
measurement of human CD45⁺ cells in mouse PB. At the end of the
treatments, BM cells were collected from one of the PDX models (PDX1, Supplemental Table 1,
#14) (n = 3 per treatment group) for RNA-sequencing analysis and spleen were
harvested from both PDX models (n = 3/group). Mice were monitored daily and
survival was recorded.