We are proposing to develop a new strategy to overcome radiation resistance in B- lineage acute lymphoblastic leukemia (ALL) using C-61, a novel SYK kinase substrate binding (P)-site inhibitor, for targeting and disrupting the anti-apoptotic SYK-STAT3 signaling network in leukemic B-cell precursors. It is our central working hypothesis that the treatment outcome of relapsed B-lineage ALL patients can be improved by inhibition of the SYK-STAT3 molecular target. This would be accomplished by using C-61 in combination with total body irradiation (TBI) in the context of HSCT.
Under Specific Aim 1, we will examine the effects of the SYK P-site inhibitor C-61 on in vitro radiation resistance of primary ALL cells from relapsed B-lineage ALL patients using quantitative flow cytometric apoptosis assays and clonogenic assays. We hypothesize that C- 61 will markedly enhance radiation-induced apoptosis of primary B-lineage ALL cells and augment radiation- induced death of their clonogenic fraction by increasing their radiation sensitivity and impairing their capacity to repair sublethal radiation damage.
Under Specific Aim 2, we will examine the effects of C-61 on in vivo radiation resistance of primary ALL cells from relapsed B-lineage ALL patients using SCID mouse xenograft models of relapsed B-lineage ALL and sublethal total body irradiation (TBI). Our hypothesis is that C-61 plus TBI regimens will be more effective than TBI alone in improving the event-free survival outcome of SCID mice challenged with primary B-lineage ALL cells.
Under Specific Aim 3, we will examine the association between the kinase expression profiles of primary ALL cells from relapsed B-lineage ALL patients and their in vitro as well as in vivo radiation resistance. In an effort aimed at identifying a composite biomarker profile that will help select patients most likely to benefit from C-61, we will correlate the kinase protein expression and activity levels of SYK, BTK, and JAK kinases of primary B-lineage ALL cells with their radiation resistance, sensitivity to C-61 induced radiosensitization in vitro, as well as C-61 induced potentiation of the anti-leukemic potency of sublethal TBI in vivo.
Under Specific Aim 4, we will study the efficacy and safety of C-61 containing single dose TBI regimens at both sublethal (2 Gy) as well as clinically applied (7 Gy) total radiation dose levels in a syngeneic murine HSCT model of radiation-resistant BCL-1 murine B-lineage leukemia. We will evaluate the efficacy and safety of TBI at doses ranging from 2-10 Gy in combination with C-61 in BALB/c mice inoculated with 1x106 BCL-1 cells in the context of syngeneic BMT. We hypothesize that the addition of C-61 will not increase the non-hematologic toxicity of TBI, while markedly potentiating its anti-leukemic efficacy. We anticipate that the incorporation of C-61 into the pre-HSCT TBI regimens of patients with relapsed B-lineage ALL will improve their treatment response and survival outcome. The proposed research has the potential provide the foundation for the development of paradigm-shifting HSCT strategies that employ C-61 containing novel TBI regimens.

Public Health Relevance

Currently, the major challenge in the treatment of childhood leukemia is to cure patients who experience a recurrence of their cancer despite intensive chemotherapy. The purpose of the proposed research is the development of an effective treatment program against chemotherapy- and radiation therapy-resistant childhood leukemia employing a new anti-leukemia drug candidate. The successful completion of this research project may provide the foundation for therapeutic innovation against childhood leukemia.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA154471-02
Application #
8250355
Study Section
Radiation Therapeutics and Biology Study Section (RTB)
Program Officer
Bernhard, Eric J
Project Start
2011-04-01
Project End
2016-03-31
Budget Start
2012-04-01
Budget End
2013-03-31
Support Year
2
Fiscal Year
2012
Total Cost
$332,000
Indirect Cost
$124,500
Name
Children's Hospital of Los Angeles
Department
Type
DUNS #
052277936
City
Los Angeles
State
CA
Country
United States
Zip Code
90027
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Myers, Dorothea E; Yiv, Seang; Qazi, Sanjive et al. (2014) CD19-antigen specific nanoscale liposomal formulation of a SYK P-site inhibitor causes apoptotic destruction of human B-precursor leukemia cells. Integr Biol (Camb) 6:766-80
Uckun, Fatih M; Qazi, Sanjive (2014) SYK as a New Therapeutic Target in B-Cell Precursor Acute Lymphoblastic Leukemia. J Cancer Ther 5:124-131
Ma, Hong; Qazi, Sanjive; Ozer, Zahide et al. (2013) Regulatory phosphorylation of Ikaros by Bruton's tyrosine kinase. PLoS One 8:e71302
Qazi, Sanjive; Uckun, Fatih M (2013) Incidence and biological significance of IKZF1/Ikaros gene deletions in pediatric Philadelphia chromosome negative and Philadelphia chromosome positive B-cell precursor acute lymphoblastic leukemia. Haematologica 98:e151-2
Uckun, Fatih M; Ma, Hong; Ishkhanian, Rita et al. (2013) Constitutive function of the Ikaros transcription factor in primary leukemia cells from pediatric newly diagnosed high-risk and relapsed B-precursor ALL patients. PLoS One 8:e80732
Uckun, Fatih M; Qazi, Sanjive; Cely, Ingrid et al. (2013) Nanoscale liposomal formulation of a SYK P-site inhibitor against B-precursor leukemia. Blood 121:4348-54
D'Cruz, Osmond J; Uckun, Fatih M (2013) Protein kinase inhibitors against malignant lymphoma. Expert Opin Pharmacother 14:707-21
Uckun, Fatih M; Qazi, Sanjive; Dibirdik, Ilker et al. (2013) Rational design of an immunoconjugate for selective knock-down of leukemia-specific E2A-PBX1 fusion gene expression in human Pre-B leukemia. Integr Biol (Camb) 5:122-32