Heat shock protein 90 (Hsp90), a highly conserved and widely expressed molecular chaperone, is mainly responsible for maintaining the correct folding of client proteins and is closely related to the stability and activation of tumour-related proteins. Hsp90α, the major isoform of Hsp90, can promote tumour cell migration and metastasis, and is abundantly secreted in highly invasive tumours. To date, most pan-Hsp90 inhibitors have been limited in their applications due to high toxicity. Herein, we described the candidate compound X10g based on a proteolysis-targeting chimaera (PROTAC) strategy that potently and selectively degraded Hsp90α. The results showed that X10g inhibited tumours better with lower toxicity in vivo. These findings demonstrate that synthesized selective Hsp90α degrader X10g provides a new strategy for breast cancer therapy.

热休克蛋白90（Hsp90）是一种高度保守、广泛表达的分子伴侣，主要负责维持客户蛋白的正确折叠，与肿瘤相关蛋白的稳定性和激活密切相关。Hsp90α是Hsp90的主要亚型，可以促进肿瘤细胞迁移和转移，并且在高侵袭性肿瘤中大量分泌。迄今为止，大多数泛Hsp90抑制剂由于毒性较高而限制了其应用。在此，我们描述了基于蛋白水解靶向嵌合体 (PROTAC) 策略的候选化合物X10g ，该策略可有效且选择性地降解 Hsp90α。结果表明，X10g具有较好的抑制肿瘤作用，且体内毒性较低。这些发现表明，合成的选择性 Hsp90α 降解剂X10g为乳腺癌治疗提供了新策略。