title: GCS overexpression is associated with multidrug resistance of human HCT-8 colon cancer cells.
abstract: OBJECTIVE
  Multidrug resistance is one of the main impediments to the successful treatment of colon cancer. Glucosylceramide synthase (GCS) which is related to multidrug resistance (MDR) can reduce the level of ceramide and can help cells escape from the ceramide-induced cell apoptosis. However, the underlying mechanism is still unclear.
  
  
  METHODS
  The cell proliferation and cell toxicity were measured with Cell Counting Kit-8 (CCK-8). The mRNA levels of GCS and MDR1 were detected by semiquantitative reverse transcription-PCR amplification, the protein levels of GCS, caspase-3 and P-gp proteins were indicated by Western blotting. The apoptosis rates of cells were measured with flow cytometry.
  
  
  RESULTS
  The relative mRNA levels of GCS in HCT-8, HCT-8/VCR, HCT-8/VCR- sh-mock and HCT-8/VCR-sh-GCS were 71.4 ± 1.1%, 95.1 ± 1.2%, 98.2 ± 1.5%, and 66.6 ± 2.1% respectively. The mRNA levels of MDR1 were respectively 61.3 ± 1.1%, 90.5 ± 1.4%, 97.6 ± 2.2% and 56.1 ± 1.2%. The IC50 of Cisplatin complexes were respectively 69.070 ± 0.253 μg/ml, 312.050 ± 1.46 μg/ml, 328.741 ± 5.648 μg/ml, 150.792 ± 0.967 μg/ml in HCT-8, HCT-8/VCR, HCT-8/VCR-sh-mock and HCT-8/VCR-sh-GCS. The protein levels of caspase-3 were 34.2 ± o.6%, 93.0 ± 0.7%, 109.09 ± 0.7%, 42.7 ± 1.3% respectively. The apoptosis rates of cells were 8.77 ± 0.14%, 12.75 ± 0.54%, 15.39 ± 0.41% and 8.49 ± 0.23% respectively.
  
  
  CONCLUSIONS
  In conclusion, our research indicated that suppression of GCS restores the sensitivity of multidrug resistance colon cancer cells to drug treatment.
authors.affiliation: Department of Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan, P.R. China.
authors.forename: Min
authors.initials: M
authors.lastname: Song
authors.forename: Weidong
authors.initials: W
authors.lastname: Zang
authors.forename: Baohua
authors.initials: B
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Cao
authors.forename: Guanrui
authors.initials: G
authors.lastname: Yang
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002945:Cisplatin / Q000494:pharmacology / Q000627:therapeutic use; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D018432:Drug Resistance, Multiple / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D015870:Gene Expression; D005964:Glucosyltransferases / Q000235:genetics*; D006801:Humans; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D014750:Vincristine / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D012333:RNA, Messenger; D014750:Vincristine; D005964:Glucosyltransferases; C023246:ceramide glucosyltransferase; D053148:Caspase 3; D002945:Cisplatin