The heat shock protein 70 (Hsp70) family of molecular chaperones are highly expressed in tumors. Inhibitors containing a pyridinium-modified benzothiazole, such as JG-98, bind to a conserved, allosteric site in Hsp70, showing promising anti-proliferative activity in cancer cells. When bound to Hsp70, the charged pyridinium makes favorable contacts; however, this moiety also increases the inhibitor's fluorescence, giving rise to undesirable interference in biochemical and cell-based assays. Here, we explore whether the pyridinium can be replaced with a neutral pyridine. We report that pyridine-modified benzothiazoles, such as compound 17h (JG2-38), have reduced fluorescence, yet retain promising anti-proliferative activity (EC50 values ~0.1 to 0.07 µM) in breast and prostate cancer cell lines. These chemical probes are expected to be useful in exploring the roles of Hsp70s in tumorigenesis and cell survival.

中文翻译：

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热激蛋白70（Hsp70）抑制剂JG-98的中性类似物。

分子伴侣的热激蛋白70（Hsp70）家族在肿瘤中高表达。含有吡啶鎓修饰的苯并噻唑的抑制剂（例如JG-98）与Hsp70中一个保守的变构位点结合，在癌细胞中显示出有希望的抗增殖活性。当与Hsp70结合时，带电的吡啶鎓会形成良好的接触。然而，该部分也增加了抑制剂的荧光，在生化和基于细胞的测定中引起了不希望的干扰。在这里，我们探讨了吡啶鎓是否可以被中性吡啶取代。我们报道吡啶修饰的苯并噻唑，例如化合物17h（JG2-38），具有降低的荧光，但在乳腺癌和前列腺癌细胞系中仍保留有希望的抗增殖活性（EC50值〜0.1至0.07 µM）。