| Summary: | 碩士 === 高雄醫學大學 === 醫學研究所 === 97 === The spindle checkpoint prevents the onset of anaphase and subsequent cell division until chromosomes are properly attached to the mitotic spindles. It has been reported that a deficiency in this mitotic spindle checkpoint causes chromosomal instability and aneuploidy in several human cancers. However, the mechanisms responsible for chromosomal instability in oral cancer are largely unknown. We analyzed the spindle checkpoint gene expression by real-time RT-PCR in oral cancer specimens. The results showed that Bub1, BubR1, Mad2 and Mps1 mRNA were all overexpressed. Arecoline, a major alkaloid of areca nut, may contribute to oral carcinogenesis through deregulating cell-cycle. To clarify the role of arecoline in abnormal cell-cycle progression, 293, KB and HEp-2 cells were used for studying the expression of the spindle checkpoint genes after arecoline treatment. We found that arecoline changed cell morphology and caused cell cycle arrest in G2/M phase. In arecoline-treated cells, chromosome alignment was disrupted and the Bub1, BubR1, Mad2 and Mps1 mRNA were also overexpressed. Western blot analysis revealed that arecoline induced Bub1, BubR1, Mad2 and Mps1 protein levels. We also found that the BubR1 expression was aberrant and arecoline could affect the structure integrity of α-tubulin in immunofluorescent experiments. Taken together, our results suggested that arecoline may deregulate the expression of the spindle checkpoint genes and contribute to oral cancer progression.
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