title: Microtubule-damaging agents enhance RASSF1A-induced cell death in lung cancer cell lines.
abstract: BACKGROUND
  Tumor suppressor gene product RASSF1A has been reported to induce mitotic arrest and apoptosis through its interaction with microtubule and binding to the Ras effector NORE1. Despite this promising antitumor action of microtubule-targeted drugs, clinical studies demonstrated that paclitaxel (TXL) and vincristine (VCS) have differential antitumor effects, depending on the status of microtubule-related genes in lung cancer patients. In this study, to provide effective chemotherapeutic treatment for lung cancer patients with the microtubule-targeted drugs, the authors investigated whether RASSF1A could enhance sensitivity to TXL and VCS, as an intrinsic microtubule modulator, in nonsmall cell lung cancer (NSCLC) cells.
  
  
  METHODS
  The growth inhibitory effects of TXL and VCS on RASSF1A-transfected cells were assessed using clonogenic and flow cytometry-based propidium iodide-labeled assay. The levels of mitosis-related proteins in RASSF1A-transfected cells after treatment with TXL or VCS were examined by Western blot analysis and in vitro kinase assay.
  
  
  RESULTS
  RASSF1A enhanced the growth inhibitory effect of TXL and VCS on NSCLC cells and bronchial epithelial transformed cells (BEAS-2B) by inducing cell cycle arrest at the G2/M-phase. Accumulation of cyclin B1, G2/M-phase-related protein, was observed when RASSF1A-transfected H1299 cells were treated with TXL or VCS, accompanied with an increase of cyclin A. Inhibition of the activity of cyclin B1/Cdc2 complex by RASSF1A and TXL or VCS was confirmed by kinase assay and knockdown of RASSF1A expression by using small interfering RNA.
  
  
  CONCLUSIONS
  RSAAF1A protein has a cooperative growth inhibitory effect with microtubule-targeted drugs through cyclin B1 accumulation on NSCLC cells, suggesting novel insights for the selection of chemotherapeutic agents.
authors.affiliation: Genomic Research Center for Lung and Breast/Ovarian Cancers, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
authors.forename: Young Mi
authors.initials: YM
authors.lastname: Whang
authors.forename: Kyong Hwa
authors.initials: KH
authors.lastname: Park
authors.forename: Hae-Yun
authors.initials: HY
authors.lastname: Jung
authors.forename: Uk Hyun
authors.initials: UH
authors.lastname: Jo
authors.forename: Yeul Hong
authors.initials: YH
authors.lastname: Kim
mesh_terms: D050256:Antimitotic Agents / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy* / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D016923:Cell Death; D045744:Cell Line, Tumor; D019926:Cyclin B / Q000378:metabolism; D056744:Cyclin B1; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism; D008870:Microtubules / Q000187:drug effects*; D017239:Paclitaxel / Q000627:therapeutic use; D034622:RNA Interference; D050257:Tubulin Modulators / Q000627:therapeutic use*; D025521:Tumor Suppressor Proteins / Q000037:antagonists & inhibitors / Q000627:therapeutic use*; D014750:Vincristine / Q000627:therapeutic use
chemical_list: D050256:Antimitotic Agents; C534699:CCNB1 protein, human; D019926:Cyclin B; D056744:Cyclin B1; C411762:RASSF1 protein, human; D050257:Tubulin Modulators; D025521:Tumor Suppressor Proteins; D014750:Vincristine; D017239:Paclitaxel