title: Heterogeneous glioblastoma cell cross-talk promotes phenotype alterations and enhanced drug resistance.
abstract: Glioblastoma multiforme is the most lethal of brain cancer, and it comprises a heterogeneous mixture of functionally distinct cancer cells that affect tumor progression. We examined the U87, U251, and U373 malignant cell lines as in vitro models to determine the impact of cellular cross-talk on their phenotypic alterations in co-cultures. These cells were also studied at the transcriptome level, to define the mechanisms of their observed mutually affected genomic stability, proliferation, invasion and resistance to temozolomide. This is the first direct demonstration of the neural and mesenchymal molecular fingerprints of U87 and U373 cells, respectively. U87-cell conditioned medium lowered the genomic stability of U373 (U251) cells, without affecting cell proliferation. In contrast, upon exposure of U87 cells to U373 (U251) conditioned medium, U87 cells showed increased genomic stability, decreased proliferation rates and increased invasion, due to a plethora of produced cytokines identified in the co-culture media. This cross talk altered the expression 264 genes in U87 cells that are associated with proliferation, inflammation, migration, and adhesion, and 221 genes in U373 cells that are associated with apoptosis, the cell cycle, cell differentiation and migration. Indirect and direct co-culturing of U87 and U373 cells showed mutually opposite effects on temozolomide resistance. In conclusion, definition of transcriptional alterations of distinct glioblastoma cells upon co-culturing provides better understanding of the mechanisms of glioblastoma heterogeneity, which will provide the basis for more informed glioma treatment in the future.
authors.affiliation: Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia.
authors.forename: Helena
authors.initials: H
authors.lastname: Motaln
authors.affiliation: Laboratory for Clinical Immunology and Molecular Genetics, University Clinic Golnik, Golnik, Slovenia.
authors.forename: Ana
authors.initials: A
authors.lastname: Koren
authors.affiliation: Department of Biotechnology and Systems Biology, National Institute of Biology, Ljubljana, Slovenia.
authors.forename: Kristina
authors.initials: K
authors.lastname: Gruden
authors.affiliation: Department of Biotechnology and Systems Biology, National Institute of Biology, Ljubljana, Slovenia.
authors.forename: Živa
authors.initials: Ž
authors.lastname: Ramšak
authors.affiliation: Department of Neurosurgery, Klinikum Großhadern, Ludwig-Maximilians-Universität, Munich, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Schichor
authors.affiliation: Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia.|Department of Biochemistry, Faculty of Chemistry and Chemical Engineering, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Tamara T
authors.initials: TT
authors.lastname: Lah
mesh_terms: D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D015153:Blotting, Western; D002448:Cell Adhesion / Q000187:drug effects / Q000235:genetics; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects / Q000235:genetics; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000378:metabolism / Q000494:pharmacology; D016207:Cytokines / Q000378:metabolism / Q000494:pharmacology; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D063990:Gene Ontology; D042822:Genomic Instability / Q000187:drug effects / Q000235:genetics; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008856:Microscopy, Fluorescence; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000077204:Temozolomide; D059467:Transcriptome / Q000187:drug effects*
chemical_list: D018906:Antineoplastic Agents, Alkylating; D017077:Culture Media, Conditioned; D016207:Cytokines; D003606:Dacarbazine; D000077204:Temozolomide
keywords: U87 cells; cellular cross-talk; glioblastoma heterogeneity; temozolomide resistance; transcriptomics