University College London Ear Institute, 332 Gray's Inn Road, London WC1X 8EE, UK.
J Cell Sci. 2023 Jul 15;136(14). doi: 10.1242/jcs.260590. Epub 2023 Jul 19.
Cisplatin is an effective platinum-based chemotherapeutic with several side effects, including ototoxicity. Cochlear cells have low rates of proliferation yet are highly susceptible to cisplatin. We hypothesised that cisplatin ototoxicity might be caused by cisplatin-protein interactions rather than cisplatin-DNA interactions. Two known cisplatin-binding proteins are involved in the stress granule (SG) response. SGs are a pro-survival mechanism involving formation of transient ribonucleoprotein complexes during stress. We examined the effects of cisplatin on SG dynamics and composition in cell lines derived from the cochlea and retinal pigment epithelium. Cisplatin-induced SGs are significantly diminished in size and quantity compared to arsenite-induced SGs and are persistent after 24 h recovery. Additionally, cisplatin pre-treated cells were unable to form a typical SG response to subsequent arsenite stress. Cisplatin-induced SGs had significant reductions in the sequestration of eIF4G and the proteins RACK1 and DDX3X. Live-cell imaging of Texas Red-conjugated cisplatin revealed its localisation to SGs and retention for at least 24 h. We show cisplatin-induced SGs have impaired assembly, altered composition and are persistent, providing evidence of an alternate mechanism for cisplatin-induced ototoxicity via an impaired SG response.
顺铂是一种有效的铂类化疗药物，具有多种副作用，包括耳毒性。耳蜗细胞的增殖率较低，但对顺铂高度敏感。我们假设顺铂耳毒性可能是由顺铂-蛋白相互作用而不是顺铂-DNA 相互作用引起的。有两种已知的顺铂结合蛋白参与应激颗粒（SG）反应。SG 是一种生存机制，涉及在应激过程中形成瞬时核糖核蛋白复合物。我们研究了顺铂对耳蜗和视网膜色素上皮细胞系中 SG 动力学和组成的影响。与亚砷酸盐诱导的 SG 相比，顺铂诱导的 SG 在大小和数量上明显减少，并且在 24 小时恢复后仍然持续存在。此外，顺铂预处理的细胞无法对随后的亚砷酸盐应激形成典型的 SG 反应。顺铂诱导的 SG 中 eIF4G 和 RACK1 和 DDX3X 蛋白的隔离显著减少。Texas Red 标记的顺铂的活细胞成像显示其定位于 SG 并至少保留 24 小时。我们表明，顺铂诱导的 SG 组装受损，组成改变且持续存在，这为顺铂诱导的耳毒性通过受损的 SG 反应提供了另一种机制的证据。
