title: Parthenolide induces apoptosis via TNFRSF10B and PMAIP1 pathways in human lung cancer cells.
abstract: BACKGROUND
  Parthenolide (PTL) is a sesquiterpene lactone which can induce apoptosis in cancer cells and eradicate cancer stem cells such as leukemia stem cells, prostate tumor-initiating cells and so on. However, the mechanism remains largely unclear.
  
  
  METHODS
  Lung cancer cells were treated with parthenolide and the cell lysates were prepared to detect the given proteins by Western Blot analysis, and the cell survival was assayed by SRB and MTT assay. Cell cycle was evaluated by DNA flow cytometry analysis. TNFRSF10B, PMAIP1, ATF4 and DDIT3 genes were knocked down by siRNA technique. Apoptosis was evaluated by using Annexin V-FITC/PI staining and flow cytometry analysis.
  
  
  RESULTS
  Parthenolide (PTL) induces apoptosis and cell cycle arrest in human lung cancer cells. Moreover, PTL treatment in NSCLC cells increases expression of TNFRSF10B/DR5 and PMAIP1/NOXA. Silencing of TNFRSF10B or PMAIP1 or overexpression of CFLAR /c-FLIP (long form) could protect cells from PTL-induced apoptosis. Furthermore, PTL could increase the levels of endoplasmic reticulum stress hallmarks such as ERN1, HSPA5, p-EIF2A, ATF4 and DDIT3. Knockdown of ATF4 and DDIT3 abrogated PTL-induced apoptosis, which suggested that PTL induced apoptosis in NSCLC cells through activation of endoplasmic reticulum stress pathway. More importantly, we found that ATF4, DDIT3, TNFRSF10B and PMAIP1 were up-regulated more intensively, while CFLAR and MCL1 were down-regulated more dramatically by PTL in A549/shCDH1 cells than that in control cells, suggesting that PTL preferred to kill cancer stem cell-like cells by activating more intensive ER stress response in cancer stem cell-like cells.
  
  
  CONCLUSIONS
  We showed that parthenolide not only triggered extrinsic apoptosis by up-regulating TNFRSF10B and down-regulating CFLAR, but also induced intrinsic apoptosis through increasing the expression of PMAIP1 and decreasing the level of MCL1 in NSCLC cells. In addition, parthenolide triggered stronger ER stress response in cancer stem cell-like cells which leads to its preference in apoptotic induction. In summary, PTL induces apoptosis in NSCLC cells by activating endoplasmic reticulum stress response.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Zhao
authors.forename: Xiangguo
authors.initials: X
authors.lastname: Liu
authors.affiliation: Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Room 103, South Building, 27 Shanda South RD, Jinan 250100, P,R, China. suling@sdu.edu.cn.
authors.forename: Ling
authors.initials: L
authors.lastname: Su
mesh_terms: D051701:Activating Transcription Factor 4 / Q000235:genetics / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D004354:Drug Screening Assays, Antitumor; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress; D015870:Gene Expression; D006801:Humans; D008175:Lung Neoplasms; D064549:Myeloid Cell Leukemia Sequence 1 Protein / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000235:genetics / Q000378:metabolism*; D012717:Sesquiterpenes / Q000494:pharmacology*; D051742:Transcription Factor CHOP / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
chemical_list: C497109:ATF4 protein, human; D000970:Antineoplastic Agents; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; C497249:DDIT3 protein, human; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; C579095:MCL1 protein, human; D064549:Myeloid Cell Leukemia Sequence 1 Protein; C498702:PMAIP1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D012717:Sesquiterpenes; C505639:TNFRSF10B protein, human; D051701:Activating Transcription Factor 4; D051742:Transcription Factor CHOP; C002669:parthenolide