title: Tetra-O-methyl nordihydroguaiaretic acid, an inhibitor of Sp1-mediated survivin transcription, induces apoptosis and acts synergistically with chemo-radiotherapy in glioblastoma cells.
abstract: Glioblastoma (GBM), one of the most malignant human neoplasias, responds poorly to current treatment modalities, with temozolomide (TMZ) being the drug most frequently used for its treatment. Tetra-O-methyl Nordihydroguaiaretic Acid (M4N) is a global transcriptional repressor of genes dependent on the Sp1 transcription factor, such as Survivin and Cdk1. In the present study we evaluated the gene expression of Survivin, its spliced variants and Cdk1 in GBM samples and cell lines. Moreover, we investigated the effects of M4N combined or not with TMZ and/or radiation on GBM primary cultures and cell lines. qRT-PCR assays were performed to determine the Survivin-spliced variants and Cdk1 gene mRNA expression in GBM tumor samples and cell lines. Cell proliferation was measured by XTT assay and cell cycle and apoptosis were determined by flow cytometry. Drug combination analyses using different schedules of administration (simultaneous and sequential) were performed on GBM cell lines and primary cultures based on the Chou-Talalay method. For clonogenic survival, doses of 2, 4, and 6 Gy of gamma radiation. were used. All Survivin-spliced variants and the Cdk1 gene were expressed in GBM samples (n = 16) and cell lines (n = 6), except the Survivin-2B variant that was only expressed in GBM cell lines. M4N treatment down regulated the expression of Cdk1, Survivin and the Survivin-ΔEx3 variant, while the Survivin-2B variant was up-regulated. M4N decreased the cell proliferation separately and synergistically with TMZ, and enhanced the effects of radiation, mainly when associated with TMZ. M4N also induced apoptotic cell death, decreased the mitotic index and arrested the cell cycle mainly in the G2/M phase. Our results suggest a potential clinical application of M4N in combination with TMZ and radiation for GB treatment.
authors.affiliation: Department of Genetics, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil. amcgen@gmail.com
authors.forename: Angel Mauricio
authors.initials: AM
authors.lastname: Castro-Gamero
authors.forename: Kleiton Silva
authors.initials: KS
authors.lastname: Borges
authors.forename: Daniel Antunes
authors.initials: DA
authors.lastname: Moreno
authors.forename: Veridiana Kill
authors.initials: VK
authors.lastname: Suazo
authors.forename: Mayara Missono
authors.initials: MM
authors.lastname: Fujinami
authors.forename: Rosane
authors.initials: R
authors.lastname: de Paula Gomes Queiroz
authors.forename: Harley Francisco
authors.initials: HF
authors.lastname: de Oliveira
authors.forename: Carlos Gilberto
authors.initials: CG
authors.lastname: Carlotti
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Scrideli
authors.forename: Luiz Gonzaga
authors.initials: LG
authors.lastname: Tone
mesh_terms: D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects; D001932:Brain Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology / Q000532:radiotherapy; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D003606:Dacarbazine / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000528:radiation effects; D005909:Glioblastoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics* / Q000378:metabolism; D020128:Inhibitory Concentration 50; D008297:Male; D009637:Masoprocol / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D008940:Mitotic Index; D012326:RNA Splicing / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology / Q000627:therapeutic use; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D000077022:Survivin; D000077204:Temozolomide; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D012333:RNA, Messenger; D011838:Radiation-Sensitizing Agents; D016329:Sp1 Transcription Factor; D000077022:Survivin; C076852:terameprocol; D009637:Masoprocol; D003606:Dacarbazine; D000077204:Temozolomide