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TSLP-Induced Alterations of Multiple Signaling Pathways in Primary CRLF2 B-ALL Xenografts

  • Parveen Shiraz
  • , Olivia Francis
  • , Ineavely Delgado
  • , Shannalee R Martinez
  • , Jacqueline Coats
  • , Katherine Salcedo Conception
  • , Karina Mayagoitia
  • , Elizabeth Ginelli
  • , Terry-Ann Milford
  • , Ross Fisher
  • , Christopher L. Morris
  • , Xiao-bing Zhang
  • , Ruijun Su
  • , Sinisa Dovat
  • , Kimberly J Payne

Research output: Contribution to journalMeeting abstractpeer-review

Abstract

B-cell acute lymphoblastic leukemia (B-ALL) with genetic defects leading to overexpression of CRLF2 (CRLF2 B-ALL) is associated with a high relapse rate and poor prognosis. CRLF2 B-ALL comprises approximately half of the high risk B-ALL characterized by a gene expression profile that is similar to that of Philadelphia chromosome-positive ALL (Ph-like B-ALL). In pediatric patients, CRLF B-ALL occurs 5 times more frequently among children of Hispanic and Native American ethnicity and is a major contributor to health disparities in ALL. CRLF2 (cytokine related ligand factor 2) together with the IL-7 receptor alpha chain, forms a receptor complex that is activated by the cytokine, TSLP (Thymic Stromal Lymphopoietin). Activation of CRLF by TSLP leads to downstream JAK-STAT5 and mTOR pathway phosphorylation even in CRLF2 B-ALL harboring activating JAK mutations. We found that primary human marrow (BM) stromal cells express TSLP (RT-PCR and ELISA) and thus provide an in vivo source of TSLP to activate CRLF2 B-ALL cells. Our next step was to develop a xenograft model system to identify the in vivo CRLF2-mediated gene expression profile and disease mechanisms that might contribute to poor prognosis. Unlike most other cytokines, mouse TSLP is species-specific and thus does not activate the human CRLF2 receptor complex. We engineered immune-deficient NOD/SCID IL-2Rγ null (NSG) mice to express normal serum levels (~20 pg/ml) of human TSLP (hTSLP+ mice), as well as control mice that lack human TSLP (hTSLP– mice). Primary human CRLF2 B-ALL were injected into hTSLP+ and hTSLP– mice and expanded for 10 weeks in vivo. Whole genome microarray was performed on CRLF2 B-ALL cells isolated by magnetic separation from the BM of hTSLP+ and hTSLP- xenograft mice. Evaluation of microarray data by Gene Set Enrichment Analysis (GSEA) and Ingenuity Pathway Analysis showed that genes downstream of mTOR pathway activation were upregulated in hTSLP+ as compared to hTSLP- mice, confirming hTSLP activity in the hTSLP+ xenograft mice. Microarray identified 280 genes that are upregulated and 281 genes that are downregulated (> 1.7 fold; p
Original languageAmerican English
Pages (from-to)3783-3783
Number of pages1
JournalBlood
Volume124
Issue number21
DOIs
StatePublished - Dec 6 2014

Disciplines

  • Biology
  • Molecular Biology
  • Immunology and Infectious Disease

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