title: The bacterial protein toxin, cytotoxic necrotizing factor 1 (CNF1) provides long-term survival in a murine glioma model.
abstract: BACKGROUND
  Glioblastomas are largely unresponsive to all available treatments and there is therefore an urgent need for novel therapeutics. Here we have probed the antineoplastic effects of a bacterial protein toxin, the cytotoxic necrotizing factor 1 (CNF1), in the syngenic GL261 glioma cell model. CNF1 produces a long-lasting activation of Rho GTPases, with consequent blockade of cytodieresis in proliferating cells and promotion of neuron health and plasticity.
  
  
  METHODS
  We have tested the antiproliferative effects of CNF1 on GL261 cells and human glioma cells obtained from surgical specimens. For the in vivo experiments, we injected GL261 cells into the adult mouse visual cortex, and five days later we administered either a single intracerebral dose of CNF1 or vehicle. To compare CNF1 with a canonical antitumoral drug, we infused temozolomide (TMZ) via minipumps for 1 week in an additional animal group.
  
  
  RESULTS
  In culture, CNF1 was very effective in blocking proliferation of GL261 cells, leading them to multinucleation, senescence and death within 15 days. CNF1 had a similar cytotoxic effect in primary human glioma cells. CNF1 also inhibited motility of GL261 cells in a scratch-wound migration assay. Low dose (2 nM) CNF1 and continuous TMZ infusion significantly prolonged animal survival (median survival 35 days vs. 28 days in vehicle controls). Remarkably, increasing CNF1 concentration to 80 nM resulted in a dramatic enhancement of survival with no obvious toxicity. Indeed, 57% of the CNF1-treated animals survived up to 60 days following GL261 glioma cell transplant.
  
  
  CONCLUSIONS
  The activation of Rho GTPases by CNF1 represents a novel potential therapeutic strategy for the treatment of central nervous system tumors.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Vannini
authors.forename: Anna
authors.initials: A
authors.lastname: Panighini
authors.forename: Chiara
authors.initials: C
authors.lastname: Cerri
authors.forename: Alessia
authors.initials: A
authors.lastname: Fabbri
authors.forename: Simonetta
authors.initials: S
authors.lastname: Lisi
authors.forename: Enrico
authors.initials: E
authors.lastname: Pracucci
authors.forename: Nicola
authors.initials: N
authors.lastname: Benedetto
authors.forename: Riccardo
authors.initials: R
authors.lastname: Vannozzi
authors.forename: Carla
authors.initials: C
authors.lastname: Fiorentini
authors.affiliation: CNR Neuroscience Institute, Via Moruzzi 1, 56124 Pisa, Italy. caleo@in.cnr.it.
authors.forename: Matteo
authors.initials: M
authors.lastname: Caleo
authors.forename: Mario
authors.initials: M
authors.lastname: Costa
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000008:administration & dosage / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D016922:Cellular Senescence / Q000187:drug effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D029968:Escherichia coli Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D005910:Glioma / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D006801:Humans; D051379:Mice; D013997:Time Factors; D014410:Tumor Stem Cell Assay
chemical_list: D000970:Antineoplastic Agents; D001427:Bacterial Toxins; D029968:Escherichia coli Proteins; C060296:cytotoxic necrotizing factor type 1