title: Comparative proteomics of colon cancer stem cells and differentiated tumor cells identifies BIRC6 as a potential therapeutic target.
abstract: Patients with liver metastases from colon carcinoma show highly variable responses to chemotherapy and tumor recurrence is frequently observed. Therapy-resistant cancer stem cells have been implicated in drug resistance and tumor recurrence. However, the factors determining therapy resistance and tumor recurrence are poorly understood. The aim of this study was to gain insight into these mechanisms by comparing the proteomes of patient-derived cancer stem cell cultures and their differentiated isogenic offspring. We established colonosphere cultures derived from resection specimens of liver metastases in patients with colon cancer. These colonospheres, enriched for colon cancer stem cells, were used to establish isogenic cultures of stably differentiated nontumorigenic progeny. Proteomics based on one-dimensional gel electrophoresis coupled to nano liquid chromatography tandem MS was used to identify proteome differences between three of these paired cultures. The resulting data were analyzed using Ingenuity Pathway Software. Out of a total data set of 3048 identified proteins, 32 proteins were at least twofold up-regulated in the colon cancer stem cells when compared with the differentiated cells. Pathway analysis showed that "cell death " regulation is strikingly different between the two cell types. Interestingly, one of the top-up-regulated proteins was BIRC6, which belongs to the class of Inhibitor of Apoptosis Proteins. Knockdown of BIRC6 sensitized colon cancer stem cells against the chemotherapeutic drugs oxaliplatin and cisplatin. This study reveals that differentiation of colon cancer stem cells is accompanied by altered regulation of cell death pathways. We identified BIRC6 as an important mediator of cancer stem cell resistance against cisplatin and oxaliplatin. Targeting BIRC6, or other Inhibitors of Apoptosis Proteins, may help eradicating colon cancer stem cells.
authors.affiliation: University Medical Center Utrecht, Department of Surgery, Utrecht, The Netherlands.
authors.forename: W J
authors.initials: WJ
authors.lastname: Van Houdt
authors.forename: B L
authors.initials: BL
authors.lastname: Emmink
authors.forename: T V
authors.initials: TV
authors.lastname: Pham
authors.forename: S R
authors.initials: SR
authors.lastname: Piersma
authors.forename: A
authors.initials: A
authors.lastname: Verheem
authors.forename: R G
authors.initials: RG
authors.lastname: Vries
authors.forename: S A
authors.initials: SA
authors.lastname: Fratantoni
authors.forename: A
authors.initials: A
authors.lastname: Pronk
authors.forename: H
authors.initials: H
authors.lastname: Clevers
authors.forename: I H M
authors.initials: IH
authors.lastname: Borel Rinkes
authors.forename: C R
authors.initials: CR
authors.lastname: Jimenez
authors.forename: O
authors.initials: O
authors.lastname: Kranenburg
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000556:secondary*; D000970:Antineoplastic Agents / Q000494:pharmacology; D002454:Cell Differentiation; D002945:Cisplatin / Q000494:pharmacology; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology*; D019008:Drug Resistance, Neoplasm; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics / Q000378:metabolism*; D008113:Liver Neoplasms / Q000378:metabolism / Q000556:secondary*; D058977:Molecular Sequence Annotation; D058990:Molecular Targeted Therapy; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism*; D009944:Organoplatinum Compounds / Q000494:pharmacology; D060066:Protein Interaction Maps; D040901:Proteomics; D011725:Pyridines / Q000494:pharmacology; D018874:Spheroids, Cellular; D053719:Tandem Mass Spectrometry; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
chemical_list: D000970:Antineoplastic Agents; C401541:BIRC6 protein, human; D051034:Inhibitor of Apoptosis Proteins; D009944:Organoplatinum Compounds; D011725:Pyridines; C431073:oxiplatin; D002945:Cisplatin