OBJECTIVETo observe the effect of polo-like kinase 1 (PLK1) gene depletion on mitosis phenotype and elucidate its vital role in gastric cancer cell line (MKN45) mitosis.

METHODSThe PLK1 expression in MKN45 cells was blocked by RNA interference (RNAi), the expression level of PLK1 mRNA and protein were measured by real-time quantitative PCR and Western blot, respectively. The morphological change of microtubules and mitosis phenotype in MKN45 cells were observed by immunofluorescence staining and laser confocal microscopy, the morphological changes of cells were observed by reverse microscopy, the variation of cell cycle distribution was detected by flow-cytometry.

RESULTSAfter RNAi targeting PLK1, PLK1 mRNA and protein level decreased obviously, the cell microtubules became obscure and lost cohesiveness, the mitosis phenotype also varied substantially (P < 0.05), more gastric cancer cells became rounded and showed G(2) phase cell DNA content (P < 0.05).

CONCLUSIONPLK1 gene plays a key role in mitosis and its inhibition can lead to mitosis arrest in MKN45 cells.