Related Experiment Videos
Drug resistance associated with loss of p53 involves extensive alterations in microtubule composition and dynamics
C M Galmarini1, K Kamath, A Vanier-Viornery
1INSERM 590-Laboratoire de Cytologie Analytique, Faculté de Médécine Rockefeller, Lyon 69373, France. fgalma@rockefeller.univ-lyon1.fr
Abstract:
In the present study, we compared the dynamics and composition of microtubules in cell lines derived from the human breast adenocarcinoma MCF-7 containing either the wild-type p53 (wt-p53; MN1) or a dominant-negative variant of p53 gene (mut-p53; MDD2). Mut-p53 cells were significantly resistant to the cytotoxicity of the microtubule-targeted drugs (vinca alkaloids and taxanes), as compared with wt-p53 cells. Studies by high-resolution time-lapse fluorescence microscopy in living cells indicated that the dynamics of microtubules of mut-p53 cells were altered in complex ways and were significantly increased as compared with microtubules in wt-p53 cells. The percentage of time microtubules spent in growing and shortening phases increased significantly, their catastrophe frequency increased, and their overall dynamicity increased by 33%. In contrast, their shortening rate and the mean length shortened decreased. Cells containing mut-p53 displayed increased polymerisation of tubulin, increased protein levels of the class IV beta-tubulin isotype, STOP and survivin, and reduced protein levels of class II beta-tubulin isotype, MAP4 and FHIT. We conclude that p53 protein may contribute to the regulation of microtubule composition and function, and that alterations in p53 function may generate complex microtubule-associated mechanisms of resistance to tubulin-binding agents.
Insights
Mutant p53 (mut-p53) breast cancer cells show resistance to microtubule drugs due to altered microtubule dynamics and composition. Wild-type p53 (wt-p53) cells are more sensitive.
Area of Science:
- Cell Biology
- Molecular Oncology
- Biochemistry
Background:
- The p53 protein is a critical tumor suppressor involved in cell cycle regulation and apoptosis.
- Microtubules are essential components of the cytoskeleton, playing key roles in cell division and intracellular transport.
- Drug resistance in cancer, particularly to microtubule-targeting agents, remains a significant clinical challenge.
Purpose of the Study:
- To investigate the impact of wild-type p53 (wt-p53) versus mutant p53 (mut-p53) on microtubule dynamics and composition.
- To compare the sensitivity of wt-p53 and mut-p53 breast cancer cells to microtubule-targeted drugs.
Main Methods:
- Utilized MCF-7 human breast adenocarcinoma cell lines expressing either wt-p53 or mut-p53.
- Employed high-resolution time-lapse fluorescence microscopy to analyze microtubule dynamics in living cells.
- Assessed protein levels of various tubulin isotypes and associated proteins using biochemical methods.
Main Results:
- Mut-p53 cells exhibited significant resistance to vinca alkaloids and taxanes compared to wt-p53 cells.
- Microtubule dynamics were significantly increased in mut-p53 cells, characterized by increased growing/shortening phases and catastrophe frequency.
- Mut-p53 cells showed altered protein expression, including increased tubulin polymerization, class IV beta-tubulin, STOP, and survivin, with decreased class II beta-tubulin, MAP4, and FHIT.
Conclusions:
- p53 protein plays a role in regulating microtubule composition and function.
- Altered p53 function can lead to complex microtubule-associated mechanisms conferring resistance to tubulin-binding agents.
- These findings suggest novel therapeutic strategies targeting microtubule dynamics in p53-mutated cancers.