title: [Effect of inhibiting the expression of hSMG-1 on chemosensitivity of human non-small cell lung cancer H1299 cells].
abstract: OBJECTIVE
  To investigate the effect of inhibiting the expression of human suppressor of morphogenesis in genitalia-1 (hSMG-1) on chemosensitivity in human lung cancer H1299 cells.
  
  
  METHODS
  Specialized small interference RNAs (siRNAs) of hSMG-1 were transfected into H1299 cells. The knockdown effect was evaluated by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence. After the administration of anti-cancer drugs, the cell viable rate was determined by cell counting kit (CCK-8) and apoptotic rate was measured by Annexin V-FITC PI double staining on flow cytometry. The apoptotic related activated caspase 3 and caspase 9 were determined by colorimetric assay.
  
  
  RESULTS
  The expression of hSMG-1 mRNA was significantly inhibited by hSMG-1 siRNA. And the inhibition rate of (73.8 ± 10.3)% was obtained (P < 0.01). The knockdown effect was further confirmed by immunofluorescence. The inhibition of hSMG-1 enhanced the sensitivity of H1299 cells to gemcitabine and cisplatin. The survival rates significantly decreased when the hSMG-1 siRNA transfected cells were treated with 10.0 mg/L gemcitabine and 10.0 mg/L cisplatin for 48 h respectively (0.51 ± 0.02 vs 0.69 ± 0.01, P < 0.01 and 0.34 ± 0.03 vs 0.48 ± 0.01, P < 0.01;all compared with control siRNA group). Annexin V-FITC PI double staining showed that, under the treatment of anti-cancer drugs, the apoptotic rate of H1299 cells was significantly increased by hSMG-1 knockdown [gemcitabine, (20.9 ± 3.4)% vs (12.0 ± 2.7)%, P < 0.05; cisplatin, (10.2 ± 1.8)% vs (4.5 ± 2.0)%, P < 0.05; all compared with control siRNA group]. Further study showed the inhibition of hSMG-1 up-regulated the activated caspase 3 and caspase 9 in the treated H1299 cells (gemcitabine, 0.1 mg/L, 48 h, caspase 3: 14.4 ± 3.8 vs 2.3 ± 0.4, P < 0.01; caspase 9: 15.5 ± 2.4 vs 4.2 ± 0.9, P < 0.01; cisplatin, 1.0 mg/L, 48 h, caspase 3: 18.8 ± 3.0 vs 6.5 ± 1.5, P < 0.01; caspase 9: 20.3 ± 4.2 vs 8.1 ± 2.0, P < 0.05; all compared with control siRNA group).
  
  
  CONCLUSIONS
  The inhibition of hSMG-1 significantly enhances the sensitivity of human lung cancer H1299 cells to gemcitabine and cisplatin through an induction of more apoptotic cells. And the activation of mitochondrial apoptotic pathway is involved.
authors.affiliation: Department of Biochemistry and Molecular Biology, Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, China.
authors.forename: Qi-sheng
authors.initials: QS
authors.lastname: Xia
authors.forename: Yuan-zhen
authors.initials: YZ
authors.lastname: Li
authors.forename: Hong-yan
authors.initials: HY
authors.lastname: Li
authors.forename: Xuan
authors.initials: X
authors.lastname: Liu
authors.forename: Bo
authors.initials: B
authors.lastname: Xu
authors.forename: Qing
authors.initials: Q
authors.lastname: Xiang
authors.forename: Chang-yuan
authors.initials: CY
authors.lastname: Yu
authors.forename: Zhi-hua
authors.initials: ZH
authors.lastname: Chen
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D034741:RNA, Small Interfering; C514704:SMG1 protein, human