Inhibitory effect of Polo-like kinase 1 depletion on mitosis and apoptosis of gastric cancer cells.
OBJECTIVE
Polo-like kinase 1 (PLK1) serine/threonine kinase plays a vital role in multiple phases of mitosis in gastric cancer cells. To investigate the effect of PLK1 depletion on mitosis and apoptosis of gastric cancer cells.


METHODS
PLK1 expression was blocked by small RNA interference(siRNA). The expression levels of PLK1, cdc2, cyclin B and caspase 3 were detected by Western blotting. Then, PLK1 depletion, cdc2 activity, cell proliferation, cell cycle phase distribution, mitotic spindle structure, and the rate of apoptosis of the PLK1 knockdown cells were observed.


RESULTS
PLK1 gene knockdown was associated with increased cyclin B expression, increased cdc2 activity (but not with the expression levels), accumulation of gastric cancer cells at G2/M, improper mitotic spindle formation, delayed chromosome separation and delayed or arrested cytokinesis. Moreover, PLK1 depletion in gastric cancer cells was associated with decreased proliferation, attenuated pro-caspase 3 levels and increased apoptosis.


CONCLUSIONS
Blockage of PLK1 expression may lead to decreased mitosis or even apoptosis in gastric cancer cells, indicating that PLK1 may be a valuable therapeutic target for gastric cancer.
Chen
Xue-Hua
XH
Department of Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, Medical School of Shanghai Jiao Tong University, Shanghai 200025 China.
Lan
Bin
B
Qu
Ying
Y
Zhang
Xiao-Qing
XQ
Cai
Qu
Q
Liu
Bing-Ya
BY
Zhu
Zheng-Gang
ZG
D017209:Apoptosis / Q000187:drug effects*; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D019926:Cyclin B / Q000032:analysis; D016195:G2 Phase / Q000187:drug effects; D006801:Humans; D008938:Mitosis / Q000187:drug effects*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D034741:RNA, Small Interfering / Q000494:pharmacology*; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000473:pathology*; D000097869:Polo-Like Kinase 1
D018797:Cell Cycle Proteins; D019926:Cyclin B; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; D000097869:Polo-Like Kinase 1