title: [The effect of Ixabepilone on NSCLC cells radio-sensitivity under quiescent or hypoxic condition].
abstract: OBJECTIVE
  To evaluate the effect of Ixabepilone on quiescent or hypoxic cells response to ionizing radiation.
  
  
  METHODS
  NCI-H460 and A549, two human NSCLC cell lines, were employed in this experiment. Quiescent cells (QC) or hypoxic cells (HC) were induced as mentioned previously and untreated cells as control. A colony forming assay was applied to compare cellular radio-sensitivity with or without Ixabepilone. Flow cytometry and Western blot analysis were used to detect cell cycle distribution and apoptosis.
  
  
  RESULTS
  Along with an increased population of G1 cell (NCI-H46 P=0.001 3; A549 P=0.006), both HC and QC were exhibited radio-resistance compared to untreated cells (survival fraction: NCI-H460 P=0.003; A549 P=0.000 1). Moreover, it was found that Ixabepilone, which induced apoptosis in both IR-treated or untreated NSCLC cells, significantly enhanced cells death under hypoxia (decrease of survival fraction: NCI-H460 P=0.000 2; A549 P<0.01).
  
  
  CONCLUSIONS
  The existence of quiescent or hypoxic cells in solid tumors poses a critical therapeutic problem since they were resistant to IR. Ixabepilone, which induces apoptosis in NSCLC, showed great radio-sensitization effect on hypoxic cells. Following work will focus on whether Ixabepilone could increase hypoxic tumor cells radio-sensitivity in vivo, which could provide useful data for the application of Ixabepilone in clinical practice.
authors.affiliation: Department of Radiotherapy of Huadong Hospital, Shanghai 200040, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Yao
authors.affiliation: the Institute of Radiation Medicine, Fudan University, Shanghai 200032, China; Email: kongzhaolu@fudan.edu.cn.
authors.forename: Zhaolu
authors.initials: Z
authors.lastname: Kong
mesh_terms: D017209:Apoptosis; D002289:Carcinoma, Non-Small-Cell Lung; D002453:Cell Cycle; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D034261:Epothilones; D006801:Humans; D008175:Lung Neoplasms; D011836:Radiation Tolerance; D011839:Radiation, Ionizing
chemical_list: D034261:Epothilones; C430592:ixabepilone