title: Acquired expression of osteopontin selectively promotes enrichment of leukemia stem cells through AKT/mTOR/PTEN/β-catenin pathways in AML cells.
abstract: OBJECTIVE
  Acute myeloid leukemia (AML) initiation and progression have been attributed to subpopulations of self-renewing leukemia stem cells (LSCs), which contribute to progression, recurrence and therapeutic resistance in leukemia. Osteopontin (OPN) plays an important role in promoting survival and drug resistance in LSCs. The aim of this study was to explore OPN roles in modulating curcumin-mediated LSC enrichment and survival in AML cell lines and primary CD34+/CD38- bone-marrow-derived AML cells.
  
  
  METHODS
  The growth inhibitory effects of curcumin (CUR) were evaluated by MTT assay in U937 and CD34+ KG-1 AML cell lines as well as primary CD34+/CD38- bone-marrow derived AML cells isolated by MACS technique. The proportion of LSC markers (CD34, CD38 and CD123) were evaluated by flow cytometry. The expression levels of OPN, AKT, mTOR, PTEN, β-catenin and NF-κB were investigated by qRT-PCR. Short interfering RNA (siRNA) against OPN was used in AML cells incubated with or without CUR.
  
  
  RESULTS
  Proportions of CD34+/CD38-/CD123+ and CD34+/CD38+/CD123+ LSCs compartment co-expressing an increased level of OPN could be enriched in AML cell lines and in patient's primary cells by CUR treatment. The expression levels of AKT, mTOR, PTEN, and β-catenin and NF-κB1, were also significantly up-regulated concurrently with OPN in the enriched CD34+ AML cells.
  
  
  CONCLUSIONS
  The increased in CUR-mediated OPN level is involved in a complex interplay of various signaling pathways resulting in cytoprotection and enrichment of CD34+ LSC compartment in CUR-treated AML cells. AKT/mTOR/PTEN/β-catenin/NF-kB signaling pathways may play roles in modulating OPN-mediated LSC cell survival and enrichment.
authors.affiliation: Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran; Blood Transfusion Research Center, High Institute for research and education in Transfusion Medicine, Tehran, Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Mohammadi
authors.affiliation: Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: shghaffari200@yahoo.com.
authors.forename: Seyed H
authors.initials: SH
authors.lastname: Ghaffari
authors.affiliation: Blood Transfusion Research Center, High Institute for research and education in Transfusion Medicine, Tehran, Iran.
authors.forename: Mojgan
authors.initials: M
authors.lastname: Shaiegan
authors.affiliation: Blood Transfusion Research Center, High Institute for research and education in Transfusion Medicine, Tehran, Iran.
authors.forename: Mahin Nikougoftar
authors.initials: MN
authors.lastname: Zarif
authors.affiliation: Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Nikbakht
authors.affiliation: Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Shiva
authors.initials: S
authors.lastname: Akbari Birgani
authors.affiliation: Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Kamran
authors.initials: K
authors.lastname: Alimoghadam
authors.affiliation: Hematology, Oncology and Stem Cell Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ardeshir
authors.initials: A
authors.lastname: Ghavamzadeh
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000378:metabolism; D018952:Antigens, CD34 / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology; D001854:Bone Marrow Cells / Q000187:drug effects / Q000378:metabolism; D045744:Cell Line, Tumor; D003474:Curcumin / Q000494:pharmacology; D006801:Humans; D053650:Interleukin-3 Receptor alpha Subunit / Q000378:metabolism; D015470:Leukemia, Myeloid, Acute / Q000235:genetics*; D016328:NF-kappa B / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D051058:Oncogene Protein v-akt / Q000235:genetics / Q000378:metabolism*; D053495:Osteopontin / Q000096:biosynthesis* / Q000235:genetics; D051059:PTEN Phosphohydrolase / Q000096:biosynthesis* / Q000235:genetics; D034741:RNA, Small Interfering / Q000494:pharmacology; D015398:Signal Transduction / Q000235:genetics; D058570:TOR Serine-Threonine Kinases / Q000096:biosynthesis* / Q000235:genetics; D051176:beta Catenin / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D018952:Antigens, CD34; D000970:Antineoplastic Agents; C495270:CTNNB1 protein, human; D053650:Interleukin-3 Receptor alpha Subunit; D016328:NF-kappa B; D034741:RNA, Small Interfering; D051176:beta Catenin; D053495:Osteopontin; C546842:MTOR protein, human; D051058:Oncogene Protein v-akt; D058570:TOR Serine-Threonine Kinases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; D051997:ADP-ribosyl Cyclase 1; D003474:Curcumin
keywords: Acute myeloid leukemia (AML); Curcumin; KG-1; Leukemic Stem Cell; Osteopontin; U937 cells