Abstract: Purpose: To analyze the spindle checkpoint function of BEP2D cells ant its malignant transformed cell lines induced by α-particles. Methods: Nocodazole, the inhibitor of spindle construction, was used to destroy the microtubule and initiate the spindle checkpoint mechanism to arrest the cells in the phase of mitosis, and mitotic index(MI) was counted under microscope. Results: BERP35T4 is a αparticles-induced transformed cell line with chromosome instability manifesting increased polyploids. After the treatment with nocodazole for 12～24 h, the mitotic index of BERP35T4 was significantly lower than that of the parental BEP2D cells and BERP35T1, another transformed cell line with relatively stable cytogenetic state. Conclusion: The spindle-checkpoint mechanism was deficient in BERP35T4 cells, and it could be related to the chromosome instability and the transformation of this cell line initiated by α particles exposure.

Key words: α-particles, spindle checkpoint, carcinogenesis