title: A combination of paclitaxel and siRNA-mediated silencing of Stathmin inhibits growth and promotes apoptosis of nasopharyngeal carcinoma cells.
abstract: BACKGROUND
  Stathmin, a microtubule associated protein (MAP), is an important molecular target for cancer therapy. Paclitaxel is one of the primary antitumor drugs targeting microtubules (MTs). We hypothesized that decreasing the expression level of Stathmin might improve the effectiveness of paclitaxel in the treatment of nasopharyngeal carcinoma (NPC).
  
  
  METHODS
  NPC cell lines, CNE1-LMP1 and HNE2, and a CNE1-LMP1 tumor xenograft mouse model were used to test both in vitro and in vivo our siRNA-based Stathmin silencing strategy. The effects of Stathmin silencing on cell proliferation, apoptosis, and viability were investigated using MTT, AO/EB staining, TUNEL, caspase protein detection, and FCM assays. Cell migration and invasion were assayed using a Transwell assay. The combined effects of Stathmin silencing and paclitaxel were investigated using MTT, FCM, Western blot and indirect immunofluorescence assays. The effect of paclitaxel on Stathmin expression in NPC cells and, in addition, A375, MGC and HeLa cells was determined by RT-PCR and Western blotting.
  
  
  RESULTS
  We found that siRNA-mediated silencing of Stathmin suppresses proliferation, induces apoptosis through the mitochondrial pathway, and causes G2/M-phase cell cycle arrest in the NPC cell lines CNE1-LMP1 and HNE2. Also, the migration and invasion of the respective NPC cells were found to be inhibited. In addition, we show that a combination of Stathmin silencing and paclitaxel is more effective than either agent alone in inhibiting proliferation and inducing apoptosis, cell cycle arrest, and MT polymerization. Furthermore, we found that Stathmin expression in the tumor cells is down-regulated by paclitaxel treatment.
  
  
  CONCLUSIONS
  siRNA-mediated silencing of Stathmin suppresses the proliferation, invasion and metastasis, and induces the apoptosis of NPC cells. Paclitaxel reduces the expression of Stathmin, and combining Stathmin silencing with paclitaxel treatment enhances MT polymerization. This combined strategy may provide a new approach for clinical NPC treatment.
authors.affiliation: Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, 410078, Hunan, People's Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Wu
authors.forename: Min
authors.initials: M
authors.lastname: Tang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wu
authors.forename: Xinxian
authors.initials: X
authors.lastname: Weng
authors.forename: Lifang
authors.initials: L
authors.lastname: Yang
authors.forename: Wen
authors.initials: W
authors.lastname: Xu
authors.forename: Wie
authors.initials: W
authors.lastname: Yi
authors.forename: Jinghe
authors.initials: J
authors.lastname: Gao
authors.forename: Ann M
authors.initials: AM
authors.lastname: Bode
authors.forename: Zigang
authors.initials: Z
authors.lastname: Dong
authors.forename: Ya
authors.initials: Y
authors.lastname: Cao
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D049109:Cell Proliferation / Q000187:drug effects*; D003131:Combined Modality Therapy; D005260:Female; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008856:Microscopy, Fluorescence; D009303:Nasopharyngeal Neoplasms / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D017239:Paclitaxel / Q000494:pharmacology*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050777:Stathmin / Q000235:genetics*; D047368:Tumor Burden / Q000187:drug effects / Q000235:genetics; D023041:Xenograft Model Antitumor Assays
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D034741:RNA, Small Interfering; D050777:Stathmin; D020169:Caspases; D017239:Paclitaxel