[Effect of tunicamycin combined with cisplatin on proliferation and apoptosis of human nasopharyngeal carcinoma cells in vitro].
OBJECTIVE
To study the effects of tunicamycin (a glycosylation inhibitor) combined with cisplatin on the proliferation and apoptosis of human nasopharyngeal carcinoma cells and explore the molecular mechanism.


METHODS
Nasopharyngeal carcinoma CNE-1 and CNE-2 cells cultured in vitro were treated with different concentrations of tunicamycin with or without cisplatin. The inhibition of cell proliferation was examined using MTT assay and colony formation assay, and the cell apoptosis was analyzed using flow cytometry with propidium iodide staining. The expressions of Bax, Bcl-2, and GRP78 in cells treated with 3 µmol/L tunicamycin with or without 6.00 µmol/L cisplatin were measured with Western blotting.


RESULTS
Treatment with tunicamycin or cisplatin obviously inhibited the proliferation of CNE-1 and CNE-2 cells. Treatment with 3 µmol/L tunicamycin for 24, 36 and 48 h resulted in a viability of 72.13%, 51.97%, and 37.56% in CNE-1 cells and 85.61%, 56.95%, and 43.66% in CNE-2 cells, respectively, and the combined treatment with 6 µmol/L cisplatin lowered the cell viability to 67.97%, 47.76%, and 34.68% in CNE-1 cells and 56.89%, 37.05%, and 29.30% in CNE-2 cells, respectively. Tunicamycin at 0.3 µmol/L combined with 0.6 µmol/L cisplatin showed an obviously enhanced inhibitory effect on colony formation of CNE-1 and CNE-2 cells. Tunicamycin treatment (3 µmol/L) of CNE-1 and CNE-2 cells for 48 h induced an apoptosis rate of only 8.89% and 8.67%, but when combined with 6 µmol/L cisplatin, the cell apoptosis rate increased to 37.02% and 32.25%, significantly higher than that in cells with cisplatin treatment alone (7.25% and 6.36%, respectively). Compared with tunicamycin and cisplatin alone, the combined treatment significantly increased Bax expression and decreased Bcl-2 expression in the cells; tunicamycin up-regulated the expression of GRP-78 and enhanced the activity of caspase-3.


CONCLUSIONS
Tunicamycin can inhibit the proliferation of CNE-1 and CNE-2 cells and enhance cisplatin-induced cell death, the mechanism of which may involve excessive endoplasmic reticulum stress response and increased activity of caspase-3.
Department of Pharmacy, Bengbu Medical College, Bengbu, China. sll13965269838@163.com
Lele
L
Song
Linyan
L
Ma
Xudong
X
Zhang
Zhiwen
Z
Jiang
Hao
H
Liu
Chenchen
C
Jiang
D017209:Apoptosis / Q000187:drug effects*; D002277:Carcinoma; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002945:Cisplatin / Q000494:pharmacology*; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000378:metabolism / Q000473:pathology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein / Q000378:metabolism
C494826:BAX protein, human; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D014415:Tunicamycin; C505407:CASP3 protein, human; D053148:Caspase 3; D002945:Cisplatin