Kawashima Daisuke, Asai Midori, Katagiri Kiyoe, Takeuchi Rika, Ohtsuka Kenzo
Department of Environmental Biology, Laboratory of Cell & Stress Biology, Chubu University, Kasugai, Aichi 487-8501, Japan.
Cell Stress Chaperones. 2009 Sep;14(5):535-43. doi: 10.1007/s12192-009-0106-0. Epub 2009 Mar 31.
Carbenoxolone (CBX) is a semisynthetic derivative of the licorice root substance glycyrrhizinic acid and has been previously reported to induce only heat shock protein 70 [Hsp70, HSPA1A (the systematic name of heat shock protein is given in the parenthesis after each HSP, according to the recent nomenclature guidelines, Kampinga et al., Cell Stress Chaperones, 14:105-111, 2008) but not other heat shock proteins (HSPs) (Nagayama et al., Life Sci. 69:2867-2873, 2001). In this study, we reinvestigated the effect of CBX on the induction of HSPs in HeLa and human neuroblastoma (A-172) cells. CBX clearly induced not only Hsp70 but also Hsp90 (HSPC1), Hsp40 (DNAJB1), and Hsp27 (HSPB1) at concentrations of 10 to 800 microM for 16 h incubation. At higher concentrations (more than 400 microM), however, CBX appeared to be toxic. Treatment of cells with CBX resulted in enhanced phosphorylation and acquisition of DNA-binding ability of heat shock transcription factor 1 (HSF1). Furthermore, characteristic HSF1 granules were formed in the nucleus, suggesting that the induction of HSPs by CBX is mediated by the activation of HSF1. Furthermore, thermotolerance was induced by CBX treatment, as determined by clonogenic survival. Although the precise target of CBX is not known at present, these results indicate that CBX is one of the molecular chaperone inducers and suggest that some pharmacological activities of CBX might be ascribable in part to its molecular chaperone-inducing property.
甘草次酸（CBX）是甘草根物质甘草酸的半合成衍生物，此前有报道称它仅能诱导热休克蛋白70 [Hsp70，HSPA1A（根据最近的命名指南，在每个热休克蛋白后的括号中给出热休克蛋白的系统名称，Kampinga等人，《细胞应激伴侣》，14:105 - 111，2008年）]，但不能诱导其他热休克蛋白（HSPs）（Nagayama等人，《生命科学》，69:2867 - 2873，2001年）。在本研究中，我们重新研究了CBX对HeLa细胞和人神经母细胞瘤（A - 172）细胞中热休克蛋白诱导的影响。在10至800微摩尔浓度下孵育16小时，CBX不仅能明显诱导Hsp70，还能诱导Hsp90（HSPC1）、Hsp40（DNAJB1）和Hsp27（HSPB1）。然而，在较高浓度（超过400微摩尔）时，CBX似乎具有毒性。用CBX处理细胞导致热休克转录因子1（HSF1）的磷酸化增强并获得DNA结合能力。此外，在细胞核中形成了特征性的HSF1颗粒，这表明CBX对热休克蛋白的诱导是由HSF1的激活介导的。此外，通过克隆存活测定发现，CBX处理可诱导耐热性。尽管目前尚不清楚CBX的确切靶点，但这些结果表明CBX是分子伴侣诱导剂之一，并提示CBX的某些药理活性可能部分归因于其分子伴侣诱导特性。
