title: Stem cell properties and the side population cells as a target for interferon-alpha in adult T-cell leukemia/lymphoma.
abstract: The cancer stem cell theory suggests that chemoresistance and recurrence of tumors are often due to the similarity of stem cell properties between normal and cancer cells. Adult T-cell leukemia/lymphoma (ATLL) has poor prognosis, suggesting that ATLL cells possess common stem cell properties. We analyzed side population (SP), a characteristic stem cell phenotype, and CD markers in ATLL cell lines. We found that several lines contained SP with expressions of some hematopoietic stem cell markers. On the other hand, treatment with interferon (IFN)-alpha is sometimes effective in ATLL, particularly combined with other drugs. We examined its effect on ATLL cells and found that IFN-alpha significantly reduced the SP proportion. Moreover, CD25-positive cells and phosphorylation of STAT1/5 and ERK were upregulated during this process. These data suggest that their stem cell properties render ATLL cells therapy-resistant, and IFN-alpha exerts its clinical effect through a reduction of the SP cell population.
authors.affiliation: Division of Clinical Immunology, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kayo
authors.forename: Hiroto
authors.initials: H
authors.lastname: Yamazaki
authors.forename: Hiroko
authors.initials: H
authors.lastname: Nishida
authors.forename: Nam H
authors.initials: NH
authors.lastname: Dang
authors.forename: Chikao
authors.initials: C
authors.lastname: Morimoto
mesh_terms: D045744:Cell Line, Tumor; D016503:Drug Delivery Systems / Q000379:methods*; D006801:Humans; D016898:Interferon-alpha / Q000008:administration & dosage*; D015458:Leukemia, T-Cell / Q000378:metabolism* / Q000473:pathology*; D009363:Neoplasm Proteins / Q000378:metabolism*; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*
chemical_list: D016898:Interferon-alpha; D009363:Neoplasm Proteins