title: Oligopeptides impairing the Myc-Max heterodimerization inhibit lung cancer cell proliferation by reducing Myc transcriptional activity.
abstract: Deregulated CMYC gene causes cell transformation and is often correlated with tumor progression and a worse clinical outcome of cancer patients. The transcription factor Myc functions by heterodimerizing with its partner, Max. As a strategy to inhibit Myc activity, we have synthesized three small peptides corresponding to segments of the leucine zipper (LZ) region of Max. The purpose of these peptides is to occupy the site of recognition between Myc and Max located in the LZ and inhibit-specific heterodimerization between these proteins. We have used the synthesized oligopeptides in two lung cancer cell lines with different levels of Myc expression. Results demonstrate that: (i) the three peptides resulted equally effective in competing the interaction between Myc and Max in vitro; (ii) they were efficiently internalized into the cells and significantly inhibited cell growth in the cells showing the highest Myc expression; (iii) one specific peptide, only nine aminoacids long, efficiently impaired the transcriptional activity of Myc in vivo, showing a more stable interaction with this protein. Our results are relevant to the development of novel anti-tumoral therapeutic strategies, directed to Myc-overexpressing tumors.
authors.affiliation: CNR, Istituto di Tecnologie Biomediche, Segrate-Milano, Italy. igea.dagnano@inmm.cnr.it
authors.forename: Igea
authors.initials: I
authors.lastname: D'Agnano
authors.forename: Alessandra
authors.initials: A
authors.lastname: Valentini
authors.forename: Giuliana
authors.initials: G
authors.lastname: Gatti
authors.forename: Alberto
authors.initials: A
authors.lastname: Chersi
authors.forename: Armando
authors.initials: A
authors.lastname: Felsani
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000494:pharmacology*; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D004273:DNA, Neoplasm / Q000378:metabolism; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D017930:Genes, Reporter; D006801:Humans; D049409:Luciferases, Firefly; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D009842:Oligopeptides / Q000138:chemical synthesis / Q000494:pharmacology*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D019098:Telomerase / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects*; D014162:Transfection
chemical_list: D000970:Antineoplastic Agents; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D004273:DNA, Neoplasm; C079439:MXD1 protein, human; C489427:MYC protein, human; D009842:Oligopeptides; D016271:Proto-Oncogene Proteins c-myc; D012097:Repressor Proteins; D049409:Luciferases, Firefly; C509186:TERT protein, human; D019098:Telomerase