title: [All-trans retinoic acid effectively inhibits breast cancer stem cells growth in vitro].
abstract: OBJECTIVE
  To detect the inhibitory effect of all-trans retinoic acid(ATRA) on breast cancer stem cells (CSCs).
  
  
  METHODS
  The inhibitory effect of ATRA on MCF-7 and SK-BR-3 cell lines was analyzed using a Cell Counting Kit-8 (CCK-8). The proportion of CD44(+)CD24(-) tumor cells of the two cell lines were measured before and after the ATRA treatment, and the role of ATRA in the regulation of CSC self-renewing ability was evaluated with a tumor sphere assay. The tumor spheres were grown in an adherent culture to evaluate the ATRA-induced differentiation of breast cancer stem cells.
  
  
  RESULTS
  ATRA effectively inhibited the unsorted cells and stem cells, but the CSCs were more sensitive to ATRA. At a concentration of 10(-6) mol/L, the inhibitory rate of MCF-7 unsorted cells and stem cells were (8.66 ± 1.06)% and (21.09 ± 3.25)%, respectively (P = 0.004). For SK-BR-3 cells, the rates were (39.19 ± 1.47)% and (51.22 ± 2.80)%, respectively (P = 0.005). The self-renewing ability of the CSCs was impaired by ATRA at a concentration of 10(-6) mol/L. The rate of MCF-7 and SK-BR-3 stem cells to form tumor sphere was 5.2% (5/96) and 13.5% (13/96), respectively. For the control group, it was 86.5% (83/96) and 93.8% (90/96), respectively (P < 0.001). ATRA also promoted the CD44(+)CD24(-) subpopulation to differentiate. SK-BR-3 stem cells were grown in an adherent culture. After using ATRA, the proportion of CD44(+)CD24(-) cells was (48.1 ± 2.5)% and that of the control group was (86.6 ± 2.5)% (P < 0.001).
  
  
  CONCLUSIONS
  ATRA effectively inhibits breast NCSCs and CSCs, but CSCs are more sensitive to ATRA. ATRA impairs the self-renewing ability of CSCs and promotes CSCs to differentiate.
authors.affiliation: Breast Cancer Center, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
authors.forename: Wei-gen
authors.initials: WG
authors.lastname: Zeng
authors.forename: Pan
authors.initials: P
authors.lastname: Hu
authors.forename: Jia-ni
authors.initials: JN
authors.lastname: Wang
authors.forename: Ren-bin
authors.initials: RB
authors.lastname: Liu
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D051927:CD24 Antigen / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D005260:Female; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000166:cytology* / Q000187:drug effects; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D051927:CD24 Antigen; D018960:Hyaluronan Receptors; D014212:Tretinoin