Correlation of defective mitotic checkpoint with aberrantly reduced expression of MAD2 protein in nasopharyngeal carcinoma cells.
Nasopharyngeal carcinoma (NPC) occurs with a high incidence in many countries in south-eastern Asia. Chromosomal abnormalities have been commonly found in NPC, but the underlying mechanism is not well understood. We determined mitotic indices, the staining pattern of nuclear DNA and cell cycle profiles of NPC cells in response to treatment with microtubule-disrupting agents, and found that the mitotic checkpoint was defective in two out of five (40%) of the tested NPC cell lines. We also observed that an aberrantly reduced expression of MAD2, one of the key components of mitotic checkpoint, correlated with the loss of checkpoint control. Our findings suggest that a defective mitotic checkpoint characterized by reduced expression of MAD2 contributes to chromosomal instability in NPC.
Wang
X
X
Department of Anatomy, Faculty of Medicine, University of Hong Kong, Pok Fu Lam Road, Hong Kong.
Jin
D Y
DY
Wong
Y C
YC
Cheung
A L
AL
Chun
A C
AC
Lo
A K
AK
Liu
Y
Y
Tsao
S W
SW
D001210:Asia, Southeastern / Q000453:epidemiology; D004273:DNA, Neoplasm / Q000032:analysis; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics*; D005434:Flow Cytometry; D006367:HeLa Cells; D006801:Humans; D015994:Incidence; D008938:Mitosis / Q000187:drug effects; D008940:Mitotic Index; D009303:Nasopharyngeal Neoplasms / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology*; D015739:Nocodazole / Q000494:pharmacology; D051899:Smad2 Protein; D015534:Trans-Activators / Q000032:analysis / Q000235:genetics*; D014407:Tumor Cells, Cultured
D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; C497782:SMAD2 protein, human; D051899:Smad2 Protein; D015534:Trans-Activators; D015739:Nocodazole