title: Cancer Stem Cell-Based Models of Colorectal Cancer Reveal Molecular Determinants of Therapy Resistance.
abstract: Colorectal cancer (CRC) therapy mainly relies on the use of conventional chemotherapeutic drugs combined, in a subset of patients, with epidermal growth factor receptor [EGFR]-targeting agents. Although CRC is considered a prototype of a cancer stem cell (CSC)-driven tumor, the effects of both conventional and targeted therapies on the CSC compartment are largely unknown. We have optimized a protocol for colorectal CSC isolation that allowed us to obtain CSC-enriched cultures from primary tumor specimens, with high efficiency. CSC isolation was followed by in vitro and in vivo validation, genetic characterization, and drug sensitivity analysis, thus generating panels of CSC lines with defined patterns of genetic mutations and therapy sensitivity. Colorectal CSC lines were polyclonal and maintained intratumor heterogeneity in terms of somatically acquired mutations and differentiation state. Such CSC-enriched cultures were used to investigate the effects of both conventional and targeted therapies on the CSC compartment in vivo and to generate a proteomic picture of signaling pathways implicated in sensitivity/resistance to anti-EGFR agents. We propose CSC lines as a sound preclinical framework to test the effects of therapies in vitro and in vivo and to identify novel determinants of therapy resistance.
  
  
  CONCLUSIONS
  Colorectal cancer stem cells (CSCs) have been shown to be responsible for tumor propagation, metastatic dissemination, and relapse. However, molecular pathways present in CSCs, as well as mechanisms of therapy resistance, are mostly unknown. Taking advantage of genetically characterized CSC lines derived from colorectal tumors, this study provides an extensive analysis of CSC response to EGFR-targeted therapy in vivo and an overview of factors implicated in therapy response or resistance. Furthermore, the implementation of a biobank of molecularly annotated CSC lines provides an innovative resource for future investigations in colorectal cancer.
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Maria Laura
authors.initials: ML
authors.lastname: De Angelis
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Ann
authors.initials: A
authors.lastname: Zeuner
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy Department of Experimental Medicine, Università "La Sapienza," Rome, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Policicchio
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy Istituto Nazionale Tumori Regina Elena, Rome, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Russo
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bruselles
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Signore
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy Istituto Nazionale Tumori Regina Elena, Rome, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Vitale
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: De Luca
authors.affiliation: Department of Clinical and Molecular Medicine, Ospedale S. Andrea, Università "La Sapienza," Rome, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Pilozzi
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Boe
authors.affiliation: Department of Surgical and Oncological Sciences, Università di Palermo, Palermo, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Stassi
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Ricci-Vitiani
authors.affiliation: Istituto Nazionale Tumori Regina Elena, Rome, Italy.
authors.forename: Carla Azzurra
authors.initials: CA
authors.lastname: Amoreo
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Pagliuca
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy Istituto Nazionale Tumori Regina Elena, Rome, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Francescangeli
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy Ospedale Pediatrico Bambino Gesù, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Tartaglia
authors.affiliation: Istituto Nazionale Tumori Regina Elena, Rome, Italy marta.baiocchi@iss.it demaria@ifo.it.
authors.forename: Ruggero
authors.initials: R
authors.lastname: De Maria
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy marta.baiocchi@iss.it demaria@ifo.it.
authors.forename: Marta
authors.initials: M
authors.lastname: Baiocchi
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D008822:Mice, Transgenic; D046228:Microarray Analysis; D008954:Models, Biological; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D040901:Proteomics; D015398:Signal Transduction / Q000235:genetics
chemical_list: D047428:Protein Kinase Inhibitors
keywords: Anti-EGFR therapy; Cancer stem cells; Cetuximab; Colorectal cancer; Proteomic arrays