title: [Enhanced growth inhibition by combined two pathway inhibitors on K-ras mutated non-small cell lung cancer cells].
abstract: OBJECTIVE
  To evaluate the effect of combined targeting of MEK and PI3K signaling pathways on K-ras mutated non-small cell lung cancer cell line A549 cells and the relevant mechanisms.
  
  
  METHODS
  A549 cells were treated with different concentrations of two inhibitors. Growth inhibition was determined by MTT assay. According to the results of MTT test, the cells were divided into four groups: the control group, PI3K inhibitor group (GDC-0941,0.5 and 5.0 µmol/L), combination group I (0.5 µmol/L AZD6244+0.5 µmol/L GDC-0941) and combination group II (5.0 µmol/L AZD6244+5.0 µmol/L GDC-0941). The cell cycle and apoptosis were analyzed by flow cytometry. The expression of proteins related to apoptosis was tested with Western blot.
  
  
  RESULTS
  Both GDC-0941 and AZD6244 inhibited the cell proliferation. The combination group II led to a stronger growth inhibition. The combination group I showed an antagonistic effect and combination group II showed an additive or synergistic effect. Compared with the control group, the combination group I led to reduced apoptotic rate [(20.70 ± 0.99)% vs. (18.65 ± 0.92 )%, P > 0.05]; Combination group II exhibited enhanced apoptotic rate [(37.85 ± 3.18)% vs. (52.27 ± 4.36)%, P < 0.01]. In addition, in the combination group II, more A549 cells were arrested in G0/G1 phase and decreased S phase (P < 0.01), due to the reduced expressions of CyclinD1 and Cyclin B1, the increased cleaved PARP and the diminished ratio of Bcl-2/Bax.
  
  
  CONCLUSIONS
  For single K-ras mutated NSCLC cell line A549 cells, combination of RAS/MEK/ERK and PI3K/AKT/mTOR inhibition showed synergistic effects depending on the drug doses. Double pathways targeted therapy may be beneficial for these patients.
authors.affiliation: Cell Resource Center, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; School of Basic Medicine, Peking Union Medical College, Beijing 100005, China.
authors.forename: Zhenli
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Cell Resource Center, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; School of Basic Medicine, Peking Union Medical College, Beijing 100005, China.
authors.forename: Zhanwen
authors.initials: Z
authors.lastname: Li
authors.affiliation: Cell Resource Center, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; School of Basic Medicine, Peking Union Medical College, Beijing 100005, China.
authors.forename: Hailiang
authors.initials: H
authors.lastname: Feng
authors.affiliation: Cell Resource Center, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; School of Basic Medicine, Peking Union Medical College, Beijing 100005, China.
authors.forename: Xiaocui
authors.initials: X
authors.lastname: Bian
authors.affiliation: Cell Resource Center, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; School of Basic Medicine, Peking Union Medical College, Beijing 100005, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Cell Resource Center, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; School of Basic Medicine, Peking Union Medical College, Beijing 100005, China. Email: liuyuqin@public.bta.net.cn.
authors.forename: Yuqin
authors.initials: Y
authors.lastname: Liu
mesh_terms: D017209:Apoptosis; D001562:Benzimidazoles; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D056744:Cyclin B1; D004357:Drug Synergism; D004791:Enzyme Inhibitors; D006801:Humans; D019869:Phosphatidylinositol 3-Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D016283:Proto-Oncogene Proteins p21(ras); D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases; D018631:ras Proteins / Q000378:metabolism*
chemical_list: D001562:Benzimidazoles; D056744:Cyclin B1; D004791:Enzyme Inhibitors; D019869:Phosphatidylinositol 3-Kinases; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras); D058570:TOR Serine-Threonine Kinases; D018631:ras Proteins; C517975:AZD 6244; C117307:KRAS protein, human; C546842:MTOR protein, human