Figure 8. HOXA9 expression and sensitivity to DOT1L inhibition in MN1^hi AML patient samples.

(A) qPCR analysis of MN1 (left axis) and HOXA9 (right axis) in 25 primary patient AML samples. MN1 expression values are shown as fold-enrichment compared with normal CD33⁺ myeloid progenitors and plotted dichotomized at the median (median = 70-fold overexpression). HOXA9 values are plotted as fold-enrichment compared with AML25 (MLL-rearranged, with known high HOXA9 expression set to 1). Error bars represent ±SEM of 2–3 technical replicates. n.d., not detected. (B) MN1 and HOXA9 expression by genotype in Wouters Leukemia data set (Oncomine). Full legend: 0, not determined (90); 1, +8 (20); 2, -5/7(Q) (29); 3, -9q (6); 4, 11q23 (10); 5, complex (13); 6, failure (12); 7, MDS -7(Q) (2); 8, MDS -Y (1); 9, MDS complex (3); 10, normal (187); 11, other (53); 12, abn(3q) (2); 13, idv(16) (34); 14, t(15;17) (21); 15, t(6;9) (6); 16, t(8;21) (35); 17, t(9;22) (2). n = 526 AML samples. (C–F) Exposure of primary patient AML samples to the DOT1L inhibitor EPZ004777 at the indicated concentrations. AML12 (MLL-rearranged [MLL-r], positive control), AML38 (high MN1/HOXA9, complex karyotype with 5q-/7q-), AML 40 (high MN1/HOXA9, complex karyotype with 5q-), AML51 (inv[16], high MN1/no HOXA9), and AML24 (AML/ETO, intermediate high MN1/no HOXA9). Shown are fold-expansion over a 14-day culture period (serial cell counts and Trypan Blue staining; error bars represent duplicate counts) (C). Wright-Giemsa stain on cytospin of AML 40 (high MN1/HOXA9, complex karyotype with 5q-) treated with DMSO or EPZ004777 (D). HOXA9 expression in AML 38 and 40 (high MN1/HOXA9) treated with DMSO or EPZ004777. Error bars over technical replicates; *P < 0.05 (two-sided t test) (E). Summary of cell growth of 3 inv(16) AML patient samples treated with DMSO or EPZ004777 (F). n = 3; *P < 0.05 (two-sided t test).