title: A novel all-trans retinoid acid derivative induces apoptosis in MDA-MB-231 breast cancer cells.
abstract: OBJECTIVE
  To explore the effect and probable mechanism of a synthetic retinoid 4-amino-2-tri-fluoromethyl- phenyl ester (ATPR) on apoptosis of MDA-MB-231 breast cancer cells.
  
  
  METHODS
  MTT assays were performed to measure the proliferation of MDA-MB-231 cells treated with different concentrations of all- trans retinoic acid (ATRA) and ATPR. Morphologic changes were observed by microscopy. The apoptosis rates and cell cycling of MDA-MB-231 cells treated with ATRA or ATPR were assessed using flow cytometry analysis. Expression of retinoic acid receptor and phosphorylation of ERK, JNK, p38 proteins were detected by Western blotting.
  
  
  RESULTS
  Treatment of the cells with the addition of 15 μmol/L ATPR for 48 h clearly demonstrated reduced cell numbers and deformed cells, whereas no changes in the number and morphology were observed after treatment with ATRA. The apoptosis rate was 33.2% after breast cancer MDA-MB-231 cells were treated by ATPR (15 μmol/L) whereas ATRA (15 μmol/L) had no apoptotic effect. ATPR inhibited the phosphorylation of ERK, JNK, and p38 while ATRA had no significant effect. ATPR inhibited the expression of BiP and increased the expression of Chop at the protein level compared with control groups, ATRA and ATPR both decreased the protein expression of RXR α, ATPR reduced the protein expression of RARβ and RXRβ while ATRA did not decrease RARβ or RXRβ.
  
  
  CONCLUSIONS
  ATPR could induce apoptosis of breast cancer MDA-MB-231 cells, possible mechanisms being binding to RARβ/RXRβ heterodimers, then activation of ER stress involving the MAPK pathway.
authors.affiliation: Department of Pathology and Pathophysiology, medical School, Southeast University, Nanjing, Jiangsu, China E-mail : xuewuhenwang@126.com, wangyuan@ahmu.edu.cn.
authors.forename: Bei
authors.initials: B
authors.lastname: Wang
authors.forename: Yun-Wen
authors.initials: YW
authors.lastname: Yan
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhou
authors.forename: Shu-Yu
authors.initials: SY
authors.lastname: Gui
authors.forename: Fei-Hu
authors.initials: FH
authors.lastname: Chen
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D010766:Phosphorylation / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D014212:Tretinoin / Q000737:chemistry* / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D014212:Tretinoin