title: Triptolide inhibits the proliferation of cells from lymphocytic leukemic cell lines in association with downregulation of NF-κB activity and miR-16-1*.
abstract: OBJECTIVE
  To examine the effects of triptolide (TPL) on T-cell leukemia cells and identify their underlying mechanisms.
  
  
  METHODS
  The cytotoxicity of TPL was assessed by MTT assay. Cell apoptosis was determined using annexin V and DAPI staining and analyzed by flow cytometry or fluorescence microscopy. The activation of caspase pathways and the expression of nuclear factor κB (NF-κB) p65 were examined by Western blotting. Differences in microRNA (miRNA) expression in Molt-4 and Jurkat cells before and after TPL treatment were identified using microarrays and real-time RT-PCR, respectively.
  
  
  RESULTS
  TPL 20-160 nmol/L treatment potently inhibited cell growth and induced apoptosis in T-cell lymphocytic leukemia cell lines. Molt-4 and Jurkat cells, however, were more sensitive to TPL than L428 and Raji cells. After 24 h of treatment, bortezomib abrogated the growth of Molt-4 and Jurkat cells with an IC(50) of 15.25 and 24.68 nmol/L, respectively. Using Molt-4 cells, we demonstrated that treatment 20-80 nmol/L inhibited the translocation of NF-κB p65 from the cytoplasm to the nucleus and that phosphorylated NF-κB p65 in nuclear extracts was down-regulated in a dose-dependent manner. Similar results were also seen in Jurkat cells but not in L428 cells, as these cells are resistant to TPL and bortezomib (a NF-κB inhibitor). Twenty-three miRNAs were differentially expressed after TPL treatment. Functional analysis revealed that TPL treatment could inhibit expression of miR-16-1* and that transfection of miR-16-1* led to significantly decreased apoptosis induced by TPL.
  
  
  CONCLUSIONS
  Our in vitro studies suggest that TPL might be an effective therapeutic agent for treatment of T-cell lymphocytic leukemia and that its cytotoxic effects could be associated with inhibition of NF-κB and down-regulation of miR-16-1*.
authors: Institute of Hematology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
authors: Hai-tao
authors: HT
authors: Meng
authors: Li
authors: L
authors: Zhu
authors: Wan-mao
authors: WM
authors: Ni
authors: Liang-shun
authors: LS
authors: You
authors: Jie
authors: J
authors: Jin
authors: Wen-bin
authors: WB
authors: Qian
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D004224:Diterpenes / Q000494:pharmacology*; D015536:Down-Regulation / Q000187:drug effects*; D004852:Epoxy Compounds / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D010616:Phenanthrenes / Q000494:pharmacology*
chemical_list: D004224:Diterpenes; D004852:Epoxy Compounds; C505362:MIRN16 microRNA, human; D035683:MicroRNAs; D016328:NF-kappa B; D010616:Phenanthrenes; C001899:triptolide