title: The combination of novel low molecular weight inhibitors of RAF (LBT613) and target of rapamycin (RAD001) decreases glioma proliferation and invasion.
abstract: Monotherapies have proven largely ineffective for the treatment of glioblastomas, suggesting that increased patient benefit may be achieved by combining therapies. Two protumorigenic pathways known to be active in glioblastoma include RAS/RAF/mitogen-activated protein kinase and phosphatidylinositol 3-kinase/AKT/target of rapamycin (TOR). We investigated the efficacy of a combination of novel low molecular weight inhibitors LBT613 and RAD001 (everolimus), which were designed to target RAF and TOR, respectively. LBT613 decreased phosphorylation of extracellular signal-regulated kinase 1 and 2, downstream effectors of RAF, in a human glioma cell line. RAD001 resulted in decreased phosphorylation of the TOR effector S6. To determine if targeting RAF and TOR activities could result in decreased protumorigenic glioma cellular behaviors, we evaluated the abilities of LBT613 and RAD001 to affect the proliferation, migration, and invasion of human glioma cells. Treatment with either LBT613 or RAD001 alone significantly decreased the proliferation of multiple human glioma cell lines. Furthermore, LBT613 and RAD001 in combination synergized to decrease glioma cell proliferation in association with G(1) cell cycle arrest. Glioma invasion is a critical contributor to tumor malignancy. The combination of LBT613 and RAD001 inhibited the invasion of human glioma cells through Matrigel to a greater degree than treatment with either drug alone. These data suggest that the combination of LBT613 and RAD001 reduces glioma cell proliferation and invasion and support examination of the combination of RAF and TOR inhibitors for the treatment of human glioblastoma patients.
authors.affiliation: Department of Surgery, Duke University Medical Center, P. O. Box 2900, Durham, NC 27710, USA.
authors.forename: Anita B
authors.initials: AB
authors.lastname: Hjelmeland
authors.forename: Kathryn P
authors.initials: KP
authors.lastname: Lattimore
authors.forename: Brian E
authors.initials: BE
authors.lastname: Fee
authors.forename: Qing
authors.initials: Q
authors.lastname: Shi
authors.forename: Sarah
authors.initials: S
authors.lastname: Wickman
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Keir
authors.forename: Mark D
authors.initials: MD
authors.lastname: Hjelmeland
authors.forename: David
authors.initials: D
authors.lastname: Batt
authors.forename: Darell D
authors.initials: DD
authors.lastname: Bigner
authors.forename: Henry S
authors.initials: HS
authors.lastname: Friedman
authors.forename: Jeremy N
authors.initials: JN
authors.lastname: Rich
mesh_terms: D017304:Annexin A5 / Q000378:metabolism; D015153:Blotting, Western; D045744:Cell Line, Tumor / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D003094:Collagen / Q000378:metabolism; D004261:DNA Replication / Q000187:drug effects; D004338:Drug Combinations; D004359:Drug Therapy, Combination; D000068338:Everolimus; D005434:Flow Cytometry; D005910:Glioma / Q000188:drug therapy / Q000473:pathology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D007546:Isoquinolines / Q000627:therapeutic use*; D007797:Laminin / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism; D011509:Proteoglycans / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D020123:Sirolimus / Q000031:analogs & derivatives* / Q000627:therapeutic use; D058570:TOR Serine-Threonine Kinases; D048490:raf Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D017304:Annexin A5; D004338:Drug Combinations; D007166:Immunosuppressive Agents; D007546:Isoquinolines; C514877:LBT 613; D007797:Laminin; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011509:Proteoglycans; C059485:matrigel; D003094:Collagen; D000068338:Everolimus; D011494:Protein Kinases; C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases; D048490:raf Kinases; D020928:Mitogen-Activated Protein Kinases; D020123:Sirolimus