Expression Levels of a Kinesin-13 Microtubule Depolymerase Modulates the Effectiveness of Anti-Microtubule AgentsReportar como inadecuado

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Chemotheraputic drugs often target the microtubule cytoskeleton as a means to disrupt cancer cell mitosis and proliferation. Anti-microtubule drugs inhibit microtubule dynamics, thereby triggering apoptosis when dividing cells activate the mitotic checkpoint. Microtubule dynamics are regulated by microtubule-associated proteins MAPs; however, we lack a comprehensive understanding about how anti-microtubule agents functionally interact with MAPs. In this report, we test the hypothesis that the cellular levels of microtubule depolymerases, in this case kinesin-13 s, modulate the effectiveness of the microtubule disrupting drug colchicine.

Methodology-Principal Findings

We used a combination of RNA interference RNAi, high-throughput microscopy, and time-lapse video microscopy in Drosophila S2 cells to identify a specific MAP, kinesin-like protein 10A KLP10A, that contributes to the efficacy of the anti-microtubule drug colchicine. KLP10A is an essential microtubule depolymerase throughout the cell cycle. We find that depletion of KLP10A in S2 cells confers resistance to colchicine-induced microtubule depolymerization to a much greater extent than depletion of several other destabilizing MAPs. Using image-based assays, we determined that control cells retained 58% ±2%SEM of microtubule polymer when after treatment with 2 µM colchicine for 1 hour, while cells depleted of KLP10A by RNAi retained 74% ±1%SEM. Likewise, overexpression of KLP10A-GFP results in increased susceptibility to microtubule depolymerization by colchicine.


Our results demonstrate that the efficacy of microtubule destabilization by a pharmacological agent is dependent upon the cellular expression of a microtubule depolymerase. These findings suggest that expression levels of Kif2A, the human kinesin-13 family member, may be an attractive biomarker to assess the effectiveness of anti-microtubule chemotherapies. Knowledge of how MAP expression levels affect the action of anti-microtubule drugs may prove useful for evaluating possible modes of cancer treatment.

Autor: Gregory V. Schimizzi, Joshua D. Currie, Stephen L. Rogers



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