title: GRP78 upregulation-induced increase in cisplatin sensitivity of SPCA1 lung cancer cells.
abstract: BACKGROUND
  Glucose regulated protein 78 (GRP78), an endoplasmic reticulum (ER) chaperone, plays a critical role in chemotherapy resistance in a variety of cancers. In this study, we investigated the up-regulation of GRP78 induced by A23187 and its association with the chemotherapeutical sensibility to cisplatin in human lung cancer cell line SPCA1.
  
  
  METHODS
  SPCA1 cells were pretreated with A23187 at different concentrations. The expression of GRP78 at the mRNA level was analyzed by RT-PCR; the expression of GRP78 at the protein level was determined by Western blotting and immunofluorescence assay. Cell survival was determined by MTT assay. Cell apoptosis was analyzed by flow cytometry.
  
  
  RESULTS
  The expression of GRP78 at both the mRNA and protein levels was obviously induced by A23187 in SPCA1 cells, with an elevation of GRP78 by 2.1-fold at the mRNA level and by 3.8-fold at the protein level compared to the control. There was a dose-dependent response. Survival curve analysis demonstrated that A23187 induction caused a significant reduction of survival for the cells subjected to cisplatin treatment (P < 0.05). After treatment by cisplatin, the percentage of apoptotic cells in the A23187 pretreated group increased about three fold compared with the control group ((27.53 ± 4.32)% vs. (9.25 ± 3.64)%, P < 0.05).
  
  
  CONCLUSIONS
  A23187 treatment was fairly effective for the induction of GRP78 in SPCA1 cells at both the mRNA and protein levels. To a certain extent, GRP78 up-regulation by A23187 was associated with the enhancement of drug sensitivity to cisplatin in human lung cancer cell line SPCA1.
authors.affiliation: Department of Respiratory Medicine, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning 116001, China.
authors.forename: Li-Chuan
authors.initials: LC
authors.lastname: Zhang
authors.forename: Jia-Rui
authors.initials: JR
authors.lastname: Wang
authors.forename: Long
authors.initials: L
authors.lastname: Zhao
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.forename: Su-Fang
authors.initials: SF
authors.lastname: Fan
authors.forename: Li-Xia
authors.initials: LX
authors.lastname: Chen
authors.forename: Shu-Juan
authors.initials: SJ
authors.lastname: Shao
authors.forename: Joseph
authors.initials: J
authors.lastname: Molnár
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D000001:Calcimycin / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D000091342:Endoplasmic Reticulum Chaperone BiP; D005434:Flow Cytometry; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000970:Antineoplastic Agents; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D000001:Calcimycin; D002945:Cisplatin