title: Cancer-associated adipocytes promotes breast tumor radioresistance.
abstract: Mature adipocytes are excellent candidates to influence tumor behavior through heterotypic signaling processes since these cells produce hormones, growth factors, cytokines and other molecules, a heterogeneous group of molecules named adipokines. Using a 2D coculture system, we demonstrate that breast tumor cells previously co-cultivated with mature adipocytes exhibit radioresistance and an earlier and higher increase in the effector kinase Chk1, a phenotype that was associated with decreased cell death as compared to tumor cells grown alone. Interestingly, the adipocytes-induced tumor changes taking place during the coculture time preceding the exposure to IR were sufficient to confer the radioresistant effect. Notorious among the changes brought by adipocytes was the significant increase of IL-6 expression in tumor cells, whose activity may well account for the observed tumor cell protection from IR toxicity. Indeed, our data confirmed the protective role of this cytokine as tumor cells incubated after irradiation with recombinant IL-6 exhibit an increased in Chk1 phosphorylation and a radioresistant phenotype, thus far recapitulating the effects observed in the presence of adipocytes. Our current study sheds light on a new role of tumor-surrounding adipocytes in fostering a radioresistant phenotype in breast tumors, a finding that might have important clinical implications in obese patients that frequently exhibit aggressive diseases.
authors.affiliation: Université de Toulouse, UPS, F-31077 Toulouse Cedex, France.
authors.forename: Ludivine
authors.initials: L
authors.lastname: Bochet
authors.forename: Aline
authors.initials: A
authors.lastname: Meulle
authors.forename: Sandrine
authors.initials: S
authors.lastname: Imbert
authors.forename: Bernard
authors.initials: B
authors.lastname: Salles
authors.forename: Philippe
authors.initials: P
authors.lastname: Valet
authors.forename: Catherine
authors.initials: C
authors.lastname: Muller
mesh_terms: D017667:Adipocytes / Q000473:pathology*; D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D002470:Cell Survival; D000071877:Checkpoint Kinase 1; D018920:Coculture Techniques; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis; D051379:Mice; D011494:Protein Kinases / Q000096:biosynthesis; D011836:Radiation Tolerance
chemical_list: D015850:Interleukin-6; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; C000605869:Chek1 protein, mouse