Li et al. Mouse Model of ETV6-RUNX1 B-cell ALL, Supplemental Material

Supplemental Figure S1: TEL-AML1 expression does not impact survival.

Cohorts of mice expressing TEL-AML1 as a result of induction by Tie2-Cre were compared to mice carrying the TEL-AML1 transgene but lacking the Tie2-Cre transgene and to ZEG mice in which the control EGFP transgene was induced by Tie2-Cre. Cohorts of control (Cre-/TA1+) mice (n=61), Cre/ZEG mice (n=58), and Cre/TA1 mice (n=62) were followed for 14-25 months. Curves show equivalent survival for animals that became ill during the course of the study. Animals that were euthanized without signs of illness were censored at the time of death. Analysis of the cause of death in these cohorts revealed only sporadic tumors that did not cluster with genotype (4-6 malignancies/group).

Supplemental Figure S2: Gamma irradiation induces disease in TEL-AML1 mice.

Cohorts of irradiated Cre/ZEG mice (n=19) and irradiated Cre/TA1 mice (n=14) were followed for 15-22 months. Curves show a trend towards decreased survival of Cre/TA1 mice that became ill during the course of the study (median survival for Cre/TA1 vs. Cre/ZEG 338 vs. 675 days, p=.06). Animals that were euthanized without signs of illness were censored at the time of death. In the Cre/ZEG cohort of 19 irradiated mice, two mice developed a thymic lymphoma, two mice developed non-hematopoietic tumors (an adenocarcinoma was found in the abdomen of one animal and one mouse developed a lung tumor), 14 mice were euthanized without evidence of malignancy, and the cause of death in one animal could not be evaluated. In the Cre/TA1 cohort of 14 irradiated mice, two mice developed thymic lymphoma, four mice developed myeloid disease (three myeloid leukemias and one mouse developed disease compatible with a myelodysplastic syndrome), one mouse developed a limb tumor, four animals were euthanized without evidence of malignancy, and the cause of death in two animals could not be evaluated. These data suggest that, in the presence of Cdkn2a, following irradiation TEL-AML1 leads to decreased survival and to increased hematopoietic neoplasia, in particular myeloid disease.

Supplemental Figure S3. Representative B-cell lymphoma/leukemia in Cdkn2a null mice that express TEL-AML1.

A, C, E: Normal mouse. B, D, F: Representative of B-cell disease in Cre/TA1 Cdkn2a null mice. A, B: Marrow cytospin. Wright’s Giemsa stain. C, D: Liver, hematoxylin & eosin. E, F: Spleen, hematoxylin & eosin. Scale bar shown in panel A represent 8 microns for panels A&B, 30 microns for panels C&D, and 12 microns for panels E&F. Note undifferentiated cytology of marrow cells, marked infiltrate in liver, and replacement of normal mix of mature cells at boundary of splenic red and white pulp with monotonous lymphoid population of intermediate size with moderately open chromatin.

Supplemental Figure S4. Immunophenotype and transgene expression in TEL-AML1 B-cell lymphoblastic leukemia/lymphoma.

A: Splenocytes of a representative B-cell lymphoma/leukemia that arose in a Cre/TA1 Cdkn2a null mouse. Splenocytes expressing modest EGFP are gated and show an immature B-cell immunophenotype.

B: RNA was prepared from B-cell lymphoma/leukemia that arose in Cdkn2a null mice with (1414) or without (1609) TEL-AML1 and was converted to cDNA (RT) or not (no RT). Prominent band in 1414 RT lane shows expression of the TEL-AML1 transcript.

C: Cell lysates were prepared from B-cell lymphoma/leukemia that arose in Cdkn2a null mice without (1388) or with (959) TEL-AML1. 959shows modest expression of a 98KDa protein, corresponding to TEL-AML1. (We were also able to demonstrate TEL-AML1 expression in a mast cell neoplasm and a histiocytic sarcoma from Cre/TA1 Cdkn2a null mice, data not shown). HL60 cell line shows strong signal at 53 kDa corresponding to endogenous TEL protein. For the leukemic sample the band intensities for TEL-AML1 and endogenous TEL were similar, suggesting that the transgene was expressed at near physiologic levels.-actin was used as a loading control.