Cancer cells rely on the chaperone heat shock protein 70 (Hsp70) for survival and proliferation. Recently, benzothiazole rhodacyanines have been shown to bind an allosteric site on Hsp70, interrupting its binding to nucleotide-exchange factors (NEFs) and promoting cell death in breast cancer cell lines. However, proof-of-concept molecules, such as JG-98, have relatively modest potency (EC₅₀ ≈ 0.7–0.4 μM) and are rapidly metabolized in animals. Here, we explored this chemical series through structure- and property-based design of ∼300 analogs, showing that the most potent had >10-fold improved EC₅₀ values (∼0.05 to 0.03 μM) against two breast cancer cells. Biomarkers and whole genome CRISPRi screens confirmed members of the Hsp70 family as cellular targets. On the basis of these results, JG-231 was found to reduce tumor burden in an MDA-MB-231 xenograft model (4 mg/kg, ip). Together, these studies support the hypothesis that Hsp70 may be a promising target for anticancer therapeutics.

中文翻译：

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探索苯并噻唑玫瑰花青作为蛋白质-蛋白质与热休克蛋白 70 (Hsp70) 相互作用的变构抑制剂。

癌细胞依靠伴侣热休克蛋白 70 (Hsp70) 来生存和增殖。最近，苯并噻唑罗丹青素已被证明与 Hsp70 上的变构位点结合，中断其与核苷酸交换因子 (NEF) 的结合并促进乳腺癌细胞系中的细胞死亡。然而，概念验证分子，如 JG-98，具有相对适中的效力（EC ₅₀ ≈ 0.7–0.4 μM），并且在动物中迅速代谢。在这里，我们通过~300 种类似物的基于结构和特性的设计探索了这个化学系列，表明最有效的 EC ₅₀提高了 10 倍以上值（~0.05 至 0.03 μM）对抗两种乳腺癌细胞。生物标志物和全基因组 CRISPRi 筛选证实 Hsp70 家族的成员是细胞靶点。基于这些结果，发现 JG-231 可减少 MDA-MB-231 异种移植模型（4 mg/kg，腹腔注射）中的肿瘤负荷。总之，这些研究支持 Hsp70 可能是抗癌治疗的有希望的靶点的假设。