title: Multicellular tumor spheroid model to evaluate spatio-temporal dynamics effect of chemotherapeutics: application to the gemcitabine/CHK1 inhibitor combination in pancreatic cancer.
abstract: BACKGROUND
  The multicellular tumor spheroid (MCTS) is an in vitro model associating malignant-cell microenvironment and 3D organization as currently observed in avascular tumors.
  
  
  METHODS
  In order to evaluate the relevance of this model for pre-clinical studies of drug combinations, we analyzed the effect of gemcitabine alone and in combination with the CHIR-124 CHK1 inhibitor in a Capan-2 pancreatic cell MCTS model.
  
  
  RESULTS
  Compared to monolayer cultures, Capan-2 MCTS exhibited resistance to gemcitabine cytotoxic effect. This resistance was amplified in EGF-deprived quiescent spheroid suggesting that quiescent cells are playing a role in gemcitabine multicellular resistance. After a prolonged incubation with gemcitabine, DNA damages and massive apoptosis were observed throughout the spheroid while cell cycle arrest was restricted to the outer cell layer, indicating that gemcitabine-induced apoptosis is directly correlated to DNA damages. The combination of gemcitabine and CHIR-124 in this MCTS model, enhanced the sensitivity to the gemcitabine antiproliferative effect in correlation with an increase in DNA damage and apoptosis.
  
  
  CONCLUSIONS
  These results demonstrate that our pancreatic MCTS model, suitable for both screening and imaging analysis, is a valuable advanced tool for evaluating the spatio-temporal effect of drugs and drug combinations in a chemoresistant and microenvironment-depending tumor model.
authors.affiliation: USR 3388 CNRS/Pierre Fabre, Centre de Recherche et Développement Pierre Fabre, Toulouse, France. isabelle.dufau@etac.cnrs.fr
authors.forename: Isabelle
authors.initials: I
authors.lastname: Dufau
authors.forename: Céline
authors.initials: C
authors.lastname: Frongia
authors.forename: Flavie
authors.initials: F
authors.lastname: Sicard
authors.forename: Laure
authors.initials: L
authors.lastname: Dedieu
authors.forename: Pierre
authors.initials: P
authors.lastname: Cordelier
authors.forename: Frédéric
authors.initials: F
authors.lastname: Ausseil
authors.forename: Bernard
authors.initials: B
authors.lastname: Ducommun
authors.forename: Annie
authors.initials: A
authors.lastname: Valette
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D021441:Carcinoma, Pancreatic Ductal / Q000188:drug therapy* / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000502:physiology; D006801:Humans; D008954:Models, Biological; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011804:Quinolines / Q000494:pharmacology*; D011812:Quinuclidines / Q000494:pharmacology*; D018874:Spheroids, Cellular / Q000187:drug effects; D014407:Tumor Cells, Cultured; D059016:Tumor Microenvironment; D000093542:Gemcitabine
chemical_list: D000970:Antineoplastic Agents; C518919:CHIR-124; D047428:Protein Kinase Inhibitors; D011804:Quinolines; D011812:Quinuclidines; D003841:Deoxycytidine; D000093542:Gemcitabine