This project is the result of a long-term collaboration between the principal investigator, a basic scientist, and physician scientists and is designed to identify determinants of treatment response in childhood acute lymphoblastic leukemia (ALL). The focus is on methotrexate (MTX) and 6-mercaptopurine (6-MP), antimetabolites that continue to be cornerstones of modern treatment protocols for ALL, and on critical unanswered questions relating to the effective clinical use of these agents. While major progress has been made in treating childhood ALL, this, in part, reflects subgroups comprising nearly 50% of patients with uniquely good prognoses. However, success in the treatment of other patients has lagged behind. We previously demonstrated: (a) a extraordinarily wide range (88-fold) of expression of the human reduced folate carrier (hRFC), the membrane transport system for MTX and tetrahydrofolates, in ALL lymphoblasts, and often disproportionate to levels of MTX transport (b) elevated hRFC expression in good prognosis ALL phenotypes, including hyperdiploidy and t(12;21); and (e) altered hRFC mRNA splice forms, gene sequence variants in the hRFC coding sequence, and a high frequency sequence deletion in a hRFC promoter. Studies were initiated to explore the contributions of (d) the high frequency C677T single nucleotide polymorphism in the methylene tetrahydrofolate reductase (MTHFR) gene and (e) the family of multidrug resistance proteins (MRPs) to chemotherapy response and resistance in pediatric ALLs. In this application, we propose to use primary ALL specimens and ALL xenografts engrafted in NOD-SCID mice to systematically establish: (i) the relationships between patterns of hRFC expression and MTX transport and sensitivities; (ii) the molecular mechanisms that result in the wide range of hRFC expression in primary specimens from the major hRFC-B promoter by in vitro and in vivo assays; (iii) the roles of gene and transcript sequence variants for hRFC and MTHFR as determinants of MTX response and resistance by high-throughput screening of ALL and non-ALL specimens and functional analysis in transfected cells; and (iv) the roles of the MRPs as determinants of MTX and 6-MP accumulations and sensitivities in ALL and transfected cells. Our results should foster the rational chemotherapy of childhood ALL by identifying patients most likely to respond to antimetabolite treatments, and/or who are likely to experience excessive toxicities. Our studies should also lead to new ALL therapies and be relevant to other malignant and non-malignant diseases treated with antifolate drugs. From the key role of hRFC in folate accumulations in mammalian cells and the potential contributions of folate deficiencies to chromosomal instability and malignant transformation, cardiovascular disease, and fetal abnormalities, our results should have far-reaching significance to human heath and disease.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA076641-10
Application #
7152491
Study Section
Experimental Therapeutics Subcommittee 1 (ET)
Program Officer
Merritt, William D
Project Start
1998-01-01
Project End
2008-12-31
Budget Start
2007-01-01
Budget End
2008-12-31
Support Year
10
Fiscal Year
2007
Total Cost
$247,760
Indirect Cost
Name
Wayne State University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
001962224
City
Detroit
State
MI
Country
United States
Zip Code
48202
Medyouf, Hind; Gao, Xiuhua; Armstrong, Florence et al. (2010) Acute T-cell leukemias remain dependent on Notch signaling despite PTEN and INK4A/ARF loss. Blood 115:1175-84
Larson Gedman, A; Chen, Q; Kugel Desmoulin, S et al. (2009) The impact of NOTCH1, FBW7 and PTEN mutations on prognosis and downstream signaling in pediatric T-cell acute lymphoblastic leukemia: a report from the Children's Oncology Group. Leukemia 23:1417-25
LaFiura, K M; Edwards, H; Taub, J W et al. (2008) Identification and characterization of novel AML1-ETO fusion transcripts in pediatric t(8;21) acute myeloid leukemia: a report from the Children's Oncology Group. Oncogene 27:4933-42
Matherly, Larry H; Hou, Zhanjun; Deng, Yijun (2007) Human reduced folate carrier: translation of basic biology to cancer etiology and therapy. Cancer Metastasis Rev 26:111-28
Ge, Yubin; Haska, Christina L; LaFiura, Katherine et al. (2007) Prognostic role of the reduced folate carrier, the major membrane transporter for methotrexate, in childhood acute lymphoblastic leukemia: a report from the Children's Oncology Group. Clin Cancer Res 13:451-7
Yang, L V; Wan, J; Ge, Y et al. (2006) The GATA site-dependent hemogen promoter is transcriptionally regulated by GATA1 in hematopoietic and leukemia cells. Leukemia 20:417-25
Liu, Mingjun; Ge, Yubin; Payton, Scott G et al. (2006) Transcriptional regulation of the human reduced folate carrier in childhood acute lymphoblastic leukemia cells. Clin Cancer Res 12:608-16
Flatley, Robin M; Payton, Scott G; Taub, Jeffrey W et al. (2004) Primary acute lymphoblastic leukemia cells use a novel promoter and 5'noncoding exon for the human reduced folate carrier that encodes a modified carrier translated from an upstream translational start. Clin Cancer Res 10:5111-22
Matherly, Larry H; Goldman, David I (2003) Membrane transport of folates. Vitam Horm 66:403-56
Zhang, L; Taub, J W; Williamson, M et al. (1998) Reduced folate carrier gene expression in childhood acute lymphoblastic leukemia: relationship to immunophenotype and ploidy. Clin Cancer Res 4:2169-77