title: Synergistic effects of combined Wnt/KRAS inhibition in colorectal cancer cells.
abstract: Activation of Wnt signalling due to inability to degrade β-catenin is found in >85% of colorectal cancers. Approximately half of colon cancers express a constitutively active KRAS protein. A significant fraction of patients show both abnormalities. We previously reported that simultaneous down-regulation of both β-catenin and KRAS was necessary to induce significant cell death and tumor growth inhibition of colorectal cancer cells. Although attractive, an RNAi-based therapeutic approach is still far from being employed in the clinical setting. Therefore, we sought to recapitulate our previous findings by the use of small-molecule inhibitors of β-catenin and KRAS. We show here that the β-catenin inhibitors PKF115-584 and pyrvinium pamoate block β-catenin-dependent transcriptional activity and synergize with the KRAS inhibitor S-trans, trans-farnesylthiosalicylic acid (FTS, salirasib) in colon cancer cells driven by Wnt and KRAS oncogenic signals, but not in cells carrying BRAF mutations. The combined use of these compounds was superior to the use of any drug alone in inducing cell growth arrest, cell death, MYC and survivin down-modulation, and inhibition of anchorage-independent growth. Expression analysis of selected cancer-relevant genes revealed down-regulation of CD44 as a common response to the combined treatments. These data provide a proof of principle for a combination therapeutic strategy in colorectal cancer.
authors.affiliation: Department of Health Sciences, University of Milano-Bicocca, Monza, Italy. luca.mologni@unimib.it
authors.forename: Luca
authors.initials: L
authors.lastname: Mologni
authors.forename: Stefania
authors.initials: S
authors.lastname: Brussolo
authors.forename: Monica
authors.initials: M
authors.lastname: Ceccon
authors.forename: Carlo
authors.initials: C
authors.lastname: Gambacorti-Passerini
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism*; D004357:Drug Synergism; D005204:Farnesol / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D051379:Mice; D010569:Perylene / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras); D011774:Pyrvinium Compounds / Q000737:chemistry / Q000494:pharmacology; D012459:Salicylates / Q000737:chemistry / Q000494:pharmacology; D051153:Wnt Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D018631:ras Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: C117307:KRAS protein, human; C538949:PKF115-584; D011518:Proto-Oncogene Proteins; D011774:Pyrvinium Compounds; D012459:Salicylates; D051153:Wnt Proteins; C093323:farnesylthiosalicylic acid; D005204:Farnesol; D010569:Perylene; C024631:pyrvinium; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins