title: A dual phosphoinositide-3-kinase alpha/mTOR inhibitor cooperates with blockade of epidermal growth factor receptor in PTEN-mutant glioma.
abstract: We have shown previously that blockade of epidermal growth factor receptor (EGFR) cooperates with a pan-selective inhibitor of phosphoinositide-3-kinase (PI3K) in EGFR-driven glioma. In this communication, we tested EGFR-driven glioma differing in PTEN status, treating with the EGFR inhibitor erlotinib and a novel dual inhibitor of PI3Kalpha and mTOR (PI-103). Erlotinib blocked proliferation only in PTEN(wt) cells expressing EGFR. Although erlotinib monotherapy showed little effect in PTEN(mt) glioma, PI-103 greatly augmented the antiproliferative efficacy of erlotinib in this setting. To address the importance of PI3K blockade, we showed in PTEN(mt) glioma that combining PI-103 and erlotinib was superior to either monotherapy or to therapy combining erlotinib with either rapamycin (an inhibitor of mTOR) or PIK-90 (an inhibitor of PI3Kalpha). These experiments show that a dual inhibitor of PI3Kalpha and mTOR augments the activity of EGFR blockade, offering a mechanistic rationale for targeting EGFR, PI3Kalpha, and mTOR in the treatment of EGFR-driven, PTEN-mutant glioma.
authors.affiliation: Department of Neurology and Brain Tumor Research Center, Comprehensive Cancer Center, Howard Hughes Medical Institute, University of California, San Francisco, CA 94143, USA. qiwen.fan@ucsf.edu
authors.forename: Qi-Wen
authors.initials: QW
authors.lastname: Fan
authors.forename: Christine K
authors.initials: CK
authors.lastname: Cheng
authors.forename: Theodore P
authors.initials: TP
authors.lastname: Nicolaides
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Hackett
authors.forename: Zachary A
authors.initials: ZA
authors.lastname: Knight
authors.forename: Kevan M
authors.initials: KM
authors.lastname: Shokat
authors.forename: William A
authors.initials: WA
authors.lastname: Weiss
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002453:Cell Cycle / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D004357:Drug Synergism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors*; D000069347:Erlotinib Hydrochloride; D005663:Furans / Q000008:administration & dosage / Q000494:pharmacology*; D005910:Glioma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D006801:Humans; D051059:PTEN Phosphohydrolase / Q000235:genetics*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011494:Protein Kinases / Q000187:drug effects*; D011725:Pyridines / Q000008:administration & dosage / Q000494:pharmacology*; D011743:Pyrimidines / Q000008:administration & dosage / Q000494:pharmacology*; D011799:Quinazolines / Q000008:administration & dosage / Q000494:pharmacology*; D058570:TOR Serine-Threonine Kinases; D016896:Treatment Outcome; D014407:Tumor Cells, Cultured