American Association for Cancer Research
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Supplementary Methods, Figures S1-S8, Tables S1-S7 from Effective Targeting of the P53–MDM2 Axis in Preclinical Models of Infant MLL-Rearranged Acute Lymphoblastic Leukemia

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journal contribution
posted on 2023-03-31, 18:41 authored by Jennifer Richmond, Hernan Carol, Kathryn Evans, Laura High, Agnes Mendomo, Alissa Robbins, Claus Meyer, Nicola C. Venn, Rolf Marschalek, Michelle Henderson, Rosemary Sutton, Raushan T. Kurmasheva, Ursula R. Kees, Peter J. Houghton, Malcolm A. Smith, Richard B. Lock

This file contains Supplementary Methods describing the Pediatric Preclinical Testing Program (PPTP) scoring method. Supplementary Figure S1: Engraftment rates and organ infiltration of MLL-ALL xenografts. Supplementary Figure S2: Comparison of expression of specific genes between MLL-ALL and BCP-ALL xenografts. Supplementary Figure S3: Comparison of HOXA gene expression between MLL-ALL and BCP-ALL xenografts. Supplementary Figure S4: RG7112 induces caspase-dependent cell death in RS4;11 cells. Supplementary Figure S5: In vivo efficacy of RG7112 against MLL-ALL xenografts. Supplementary Figure S6: Effects of RG7112 on mouse weight and haematological parameters. Supplementary Figure S7: Immunoblots of spleen-derived cells from replicate mice showing the effects of RG7112 on MLL-14 xenograft cells. Supplementary Figure S8: Relationships between TP53 and MDM2 gene expression and in vivo responses of ALL xenografts to RG7112. Supplementary Table S1: Rates of serial engraftment of MLL-ALL xenografts. Supplementary Table S2: The top 100 genes that distinguish MLL-rearranged ALL xenografts from BCP-ALL xenografts. Supplementary Table S3: Statistical analysis of genes identified by Armstrong et al (2002) between MLL-ALL and BCP-ALL xenografts. Supplementary Table S4: Details of individual mouse responses to in vivo treatment with RG7112. Supplementary Table S5: In vitro Combination Indices of RG7112 with established drugs used to treat ALL. Supplementary Table S6: In vivo efficacy of RG7112 in combination with a VXL induction-type regimen. Supplementary Table S7: Details of individual mouse responses to in vivo treatment with RG7112 combined with VXL against MLL-ALL xenografts.



Purpose: Although the overall cure rate for pediatric acute lymphoblastic leukemia (ALL) approaches 90%, infants with ALL harboring translocations in the mixed-lineage leukemia (MLL) oncogene (infant MLL-ALL) experience shorter remission duration and lower survival rates (∼50%). Mutations in the p53 tumor-suppressor gene are uncommon in infant MLL-ALL, and drugs that release p53 from inhibitory mechanisms may be beneficial. The purpose of this study was to assess the efficacy of the orally available nutlin, RG7112, against patient-derived MLL-ALL xenografts.Experimental Design: Eight MLL-ALL patient-derived xenografts were established in immune-deficient mice, and their molecular features compared with B-lineage ALL and T-ALL xenografts. The sensitivity of MLL-ALL xenografts to RG7112 was assessed in vitro and in vivo, and the ability of RG7112 to induce p53, cell-cycle arrest, and apoptosis in vivo was evaluated.Results: Gene-expression analysis revealed that MLL-ALL, B-lineage ALL, and T-ALL xenografts clustered according to subtype. Moreover, genes previously reported to be overexpressed in MLL-ALL, including MEIS1, CCNA1, and members of the HOXA family, were significantly upregulated in MLL-ALL xenografts, confirming their ability to recapitulate the clinical disease. Exposure of MLL-ALL xenografts to RG7112 in vivo caused p53 upregulation, cell-cycle arrest, and apoptosis. RG7112 as a single agent induced significant regressions in infant MLL-ALL xenografts. Therapeutic enhancement was observed when RG7112 was assessed using combination treatment with an induction-type regimen (vincristine/dexamethasone/L-asparaginase) against an MLL-ALL xenograft.Conclusions: The utility of targeting the p53–MDM2 axis in combination with established drugs for the management of infant MLL-ALL warrants further investigation. Clin Cancer Res; 21(6); 1395–405. ©2015 AACR.