Hyperfluidization-coupled membrane microdomain reorganization is linked to activation of the heat shock response in a murine melanoma cell line
Hyperfluidization-coupled membrane microdomain reorganization is linked to activation of the heat shock response in a murine melanoma cell line
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DOI：
10.1073/pnas.0702557104
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发表时间：
2007-05-08
影响因子：
11.1
通讯作者：
Vigh, Laszlo
中科院分区：
文献类型：
--
作者：
Nagy, Eniko;Balogi, Zsolt;Vigh, Laszlo
靶向肿瘤细胞中的Hsp功能目前被评估为潜在的抗癌疗法。提高对触发或减弱应激蛋白反应的分子信号的理解对于在这一领域取得进展至关重要。本研究提供的证据表明，膜流化剂苯甲醇（BA），一个记录的非变性剂，作为一个伴侣诱导剂在B16（F10）黑色素瘤细胞。已经证明这种作用基本上依赖于热休克转录因子1（HSF 1）的激活。在测试的条件下，BA诱导的HSP反应涉及HSP基因的子集的上调。研究表明，用非常类似的苯乙醇（PhA）获得的相同水平的膜流化（在核心膜区域估计）不会产生应激蛋白信号。BA，在激活热休克基因的浓度下，在体外对筏状胆固醇-鞘磷脂结构域的熔化产生深远的影响，而PhA，在膜流化中与BA等效的浓度下，没有这种影响。此外，通过在体内标记的黑色素瘤细胞与荧光素标记的探针，插入到富含胆固醇的膜域[荧光素酯的聚乙二醇衍生的胆固醇（fPEG-ChoI）]，我们发现，类似于热应激本身，BA，但不是苯丙氨酸，启动质膜微区结构的深刻改变。我们认为，除了在深层疏水区膜超流化，一个独特的重组富含胆固醇的微区也可能需要的压力信号的产生和传输，以激活热休克蛋白基因。
Targeting of the Hsp function in tumor cells is currently being assessed as potential anticancer therapy. An improved understanding of the molecular signals that trigger or attenuate the stress protein response is essential for advances to be made in this field. The present study provides evidence that the membrane fluidizer benzyl alcohol (BA), a documented nondenaturant, acts as a chaperone inducer in B16(F10) melanoma cells. it is demonstrated that this effect relies basically on heat shock transcription factor 1 (HSF1) activation. Under the conditions tested, the BA-induced Hsp response involves the up-regulation of a subset of hsp genes. it is shown that the same level of membrane fluidization (estimated in the core membrane region) attained with the closely analogous phenethyl alcohol (PhA) does not generate a stress protein signal. BA, at a concentration that activates heat shock genes, exerts a profound effect on the melting of raft-like cholesterol-sphingomyelin domains in vitro, whereas PhA, at a concentration equipotent with BA in membrane fluidization, has no such effect. Furthermore, through the in vivo labeling of melanoma cells with a fluorescein labeled probe that inserts into the cholesterol-rich membrane domains [fluorescein ester of polyethylene glycol-derivatized cholesterol (fPEG-ChoI)], we found that, similarly to heat stress per se, BA, but not PhA, initiates profound alterations in the plasma membrane microdomain structure. We suggest that, apart from membrane hyperfluidization in the deep hydrophobic region, a distinct reorganization of cholesterol-rich microdomains may also be required for the generation and transmission of stress signals to activate hsp genes.