title: High LET radiation enhances nocodazole Induced cell death in HeLa cells through mitotic catastrophe and apoptosis.
abstract: To understand how human tumor cells respond to the combined treatment with nocodazole and high LET radiation, alterations in cell cycle, mitotic disturbances and cell death were investigated in the present study. Human cervix carcinoma HeLa cells were exposed to nocodazole for 18 h immediately followed by high LET iron ion irradiation and displayed a sequence of events leading to DNA damages, mitotic aberrations, interphase restitution and endocycle as well as cell death. A prolonged mitotic arrest more than 10 h was observed following nocodazole exposure, no matter the irradiation was present or not. The occurrence of mitotic slippage following the mitotic arrest was only drug-dependent and the irradiation did not accelerate it. The amount of polyploidy cells was increased following mitotic slippage. No detectable G(2) or G(1) arrest was observed in cells upon the combined treatment and the cells reentered the cell cycle still harboring unrepaired cellular damages. This premature entry caused an increase of multipolar mitotic spindles and amplification of centrosomes, which gave rise to lagging chromosomal material, failure of cytokinesis and polyploidization. These mitotic disturbances and their outcomes confirmed the incidence of mitotic catastrophe and delayed apoptotic features displayed by TUNEL method after the combined treatment. These results suggest that the addition of high-LET iron ion irradiation to nocodazole enhanced mitotic catastrophe and delayed apoptosis in HeLa cells. These might be important cell death mechanisms involved in tumor cells in response to the treatment of antimitotic drug combined with high LET radiation.
authors.affiliation: Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, People’s Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Libin
authors.initials: L
authors.lastname: Zhou
authors.forename: Zhongying
authors.initials: Z
authors.lastname: Dai
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Jin
authors.forename: Xinguo
authors.initials: X
authors.lastname: Liu
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Furusawa
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000528:radiation effects*; D002453:Cell Cycle; D016923:Cell Death; D045744:Cell Line, Tumor; D004249:DNA Damage; D006367:HeLa Cells / Q000528:radiation effects*; D006801:Humans; D020287:In Situ Nick-End Labeling; D018499:Linear Energy Transfer; D008938:Mitosis / Q000528:radiation effects*; D015739:Nocodazole / Q000494:pharmacology*; D011123:Polyploidy; D008941:Spindle Apparatus; D014404:Tubulin / Q000737:chemistry
chemical_list: D000970:Antineoplastic Agents; D014404:Tubulin; D015739:Nocodazole