title: Effects of cisplatin on potassium currents in CT26 cells.
abstract: OBJECTIVE
  Cisplatin, a platinum-based drug, is an important weapon against many types of cancer. It is well-known that cisplatin induces apoptosis. Potassium channel plays very important role in several signaling pathways. To investigate the possibility that potassium channels also have a role in the cellular response to cisplatin, we examined the effect of cisplatin on the activity of potassium channels on CT26 cell, the colon carcinoma cell line.
  
  
  METHODS
  The cells were cultured in DMEM, supplemented with 10< heat-inactivated fetal bovine serum. At mid-log phase, cultures were harvested, washed twice in phosphate-buffered saline, and resuspended in culture medium before use. Cells were voltage-clamped using the whole-cell patch clamp technique. Membrane current data were collected and amplified.
  
  
  METHODS
  Differences between two groups were assessed by paired t-test and one sample t-test to compare the relative values. One-way ANOVA was used for all experiment with more than two groups.
  
  
  RESULTS
  Potassium currents were detected in CT26 cells and the currents were reduced by the application of tetraethylammonium (TEA) chloride, iberiotoxin, a big conductance calcium-activated potassium channel blocker and barium. The potassium currents were enhanced to 192< by the application of cisplatin (0.5 mM). Moreover, the increase of potassium currents by cisplatin was further inhibited by the application of TEA confirming the action of cisplatin on potassium channels. In addition, relative current induced by cisplatin in CT26 cells was bit larger than in normal IEC-6 cells.
  
  
  CONCLUSIONS
  Potassium currents were detected in CT26 cells and the currents were reduced by the application of tetraethylammonium (TEA) chloride, iberiotoxin, a big conductance calcium-activated potassium channel blocker and barium. The potassium currents were enhanced to 192< by the application of cisplatin (0.5 mM). Moreover, the increase of potassium currents by cisplatin was further inhibited by the application of TEA confirming the action of cisplatin on potassium channels. In addition, relative current induced by cisplatin in CT26 cells was bit larger than in normal IEC-6 cells.
authors.forename: Naveen
authors.initials: N
authors.lastname: Sharma
authors.forename: Janardhan Prasad
authors.initials: JP
authors.lastname: Bhattarai
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Pyoung Han
authors.initials: PH
authors.lastname: Hwang
authors.forename: Min Sun
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Department of Oral Physiology, School of Dentistry, Institute of Oral Bioscience, Chonbuk National University, Jeonju, South Korea.
authors.forename: Seong Kyu
authors.initials: SK
authors.lastname: Han
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002277:Carcinoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000008:administration & dosage*; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D006801:Humans; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000008:administration & dosage; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D010455:Peptides; D015221:Potassium Channels; C064719:iberiotoxin; D002945:Cisplatin; D011188:Potassium; D002118:Calcium