title: Inhibition of Nucleotide Synthesis Targets Brain Tumor Stem Cells in a Subset of Glioblastoma.
abstract: Inhibition of both the de novo (DNP) and salvage (NSP) pathways of nucleoside synthesis has been demonstrated to impair leukemia cells. We endeavored to determine whether this approach would be efficacious in glioblastoma. To diminish nucleoside biosynthesis, we utilized compound DI-39, which selectively targets NSP, in combination with thymidine (dT), which selectively targets DNP. We employed in vitro and ex vivo models to determine the effects of pretreatment with dT + DI-39 on brain tumor stem cells (BTSC). Here, we demonstrate that this combinatorial therapy elicits a differential response across a spectrum of human patient-derived glioblastoma cultures. As determined by apoptotic markers, most cultures were relatively resistant to treatment, although a subset was highly sensitive. Sensitivity was unrelated to S-phase delay and to DNA damage induced by treatment. Bioinformatics analysis indicated that response across cultures was associated with the transcription factor PAX3 (associated with resistance) and with canonical pathways, including the nucleotide excision repair pathway, PTEN (associated with resistance), PI3K/AKT (associated with sensitivity), and ErbB2-ErbB3. Our in vitro assays demonstrated that, in sensitive cultures, clonal sphere formation was reduced upon removal from pretreatment. In contrast, in a resistant culture, clonal sphere formation was slightly increased upon removal from pretreatment. Moreover, in an intracranial xenograft model, pretreatment of a sensitive culture caused significantly smaller and fewer tumors. In a resistant culture, tumors were equivalent irrespective of pretreatment. These results indicate that, in the subset of sensitive glioblastoma, BTSCs are targeted by inhibition of pyrimidine synthesis. Mol Cancer Ther; 15(6); 1271-8. ©2016 AACR.
authors.affiliation: Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California. Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California.
authors.forename: Dan R
authors.initials: DR
authors.lastname: Laks
authors.affiliation: Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, California.
authors.forename: Lisa
authors.initials: L
authors.lastname: Ta
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Crisman
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California.
authors.forename: Fuying
authors.initials: F
authors.lastname: Gao
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Coppola
authors.affiliation: Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, California. hkornblum@mednet.ucla.edu cradu@icloud.com DNathanson@mednet.ucla.edu.
authors.forename: Caius G
authors.initials: CG
authors.lastname: Radu
authors.affiliation: Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, California. hkornblum@mednet.ucla.edu cradu@icloud.com DNathanson@mednet.ucla.edu.
authors.forename: David A
authors.initials: DA
authors.lastname: Nathanson
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, California. Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, California. Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, California. The Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, California. hkornblum@mednet.ucla.edu cradu@icloud.com DNathanson@mednet.ucla.edu.
authors.forename: Harley I
authors.initials: HI
authors.lastname: Kornblum
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003842:Deoxycytidine Kinase / Q000037:antagonists & inhibitors*; D019008:Drug Resistance, Neoplasm; D004791:Enzyme Inhibitors / Q000008:administration & dosage* / Q000494:pharmacology; D005909:Glioblastoma / Q000188:drug therapy* / Q000378:metabolism; D006801:Humans; D051379:Mice; D014411:Neoplastic Stem Cells / Q000187:drug effects*; D000072041:PAX3 Transcription Factor / Q000378:metabolism; D051059:PTEN Phosphohydrolase / Q000378:metabolism; D011743:Pyrimidines / Q000008:administration & dosage* / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000008:administration & dosage* / Q000494:pharmacology; D013936:Thymidine / Q000008:administration & dosage* / Q000494:pharmacology; D023041:Xenograft Model Antitumor Assays
chemical_list: C000620842:DI-39 compound; D004791:Enzyme Inhibitors; D000072041:PAX3 Transcription Factor; C489409:PAX3 protein, human; D011743:Pyrimidines; D013449:Sulfonamides; D003842:Deoxycytidine Kinase; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; D013936:Thymidine