title: Alpha2beta1 integrin regulates lineage commitment in multipotent human colorectal cancer cells.
abstract: The human colorectal epithelium is maintained by multipotent stem cells that give rise to absorptive, mucous, and endocrine lineages. Recent evidence suggests that human colorectal cancers are likewise maintained by a minority population of so-called cancer stem cells. We have previously established a human colorectal cancer cell line with multipotent characteristics (HRA-19) and developed a serum-free medium that induces endocrine, mucous and absorptive lineage commitment by HRA-19 cells in vitro. In this study, we investigate the role of the beta1 integrin family of cell surface extracellular matrix receptors in multilineage differentiation by these multipotent human colorectal cancer cells. We show that endocrine and mucous lineage commitment is blocked in the presence of function-blocking antibodies to beta1 integrin. Function-blocking antibodies to alpha2 integrin also blocked both HRA-19 endocrine lineage commitment and enterocytic differentiation by Caco-2 human colon cancer cells; both effects being abrogated by the MEK inhibitor, PD98059, suggesting a role for ERK signaling in alpha2-mediated regulation of colorectal cancer cell differentiation. To further explore the role of alpha2 integrin in multilineage differentiation, we established multipotent cells expressing high levels of wild-type alpha2 integrin or a non-signaling chimeric alpha2 integrin. Overexpression of wild-type alpha2 integrin in HRA-19 cells significantly enhanced endocrine and mucous lineage commitment, while cells expressing the non-signaling chimeric alpha2 integrin had negligible ability for either endocrine or mucous lineage commitment. This study indicates that the collagen receptor alpha2beta1 integrin is a regulator of cell fate in human multipotent colorectal cancer cells.
authors.affiliation: Department of Histopathology, Faculty of Medicine, Imperial College London, London W12 ONN, United Kingdom. Electronic address: s.kirkland@imperial.ac.uk.
authors.forename: Susan C
authors.initials: SC
authors.lastname: Kirkland
authors.affiliation: Department of Histopathology, Faculty of Medicine, Imperial College London, London W12 ONN, United Kingdom.
authors.forename: Huijun
authors.initials: H
authors.lastname: Ying
mesh_terms: D000912:Antibodies, Neoplasm / Q000494:pharmacology; D018938:Caco-2 Cells; D002454:Cell Differentiation / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D020895:Enterocytes / Q000378:metabolism / Q000473:pathology; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D038982:Integrin alpha2beta1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D039902:Multipotent Stem Cells / Q000378:metabolism* / Q000473:pathology; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology
chemical_list: D000912:Antibodies, Neoplasm; D005419:Flavonoids; D038982:Integrin alpha2beta1; D009363:Neoplasm Proteins; D047428:Protein Kinase Inhibitors; D020930:MAP Kinase Kinase Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one