HSP70 and melanoma

 描述(申请人提供)：恶性黑色素瘤是一种破坏性的肿瘤，需要新的治疗方案。尽管BRAF和MEK抑制剂的治疗取得了成功，但对这些化合物的耐药性是一个主要障碍。同样，免疫阻断疗法是有效的，但只在一小部分人群中有效；因此，加强免疫监测疗法成功的方法是一个重大的未得到满足的临床需求。热休克蛋白的抑制一直是黑色素瘤研究的热点，尤其是因为热休克蛋白的抑制可以通过多个独立的途径靶向肿瘤，而与癌基因无关(S)。HSP70抑制剂代表了一类新的令人兴奋的化合物，已显示出治疗黑色素瘤的重要临床前前景。未转化的黑素细胞几乎不表达HSP70，而肿瘤细胞表达高达100倍的水平，从而为这些抑制剂的使用提供了一个独特的治疗窗口。这份续订申请旨在扩展维斯塔尔研究所的墨菲实验室和宾夕法尼亚大学佩雷尔曼医学院的乔治实验室对这两个实验室联合发现的一系列新型HSP70抑制剂的分析。在过去的资助期发表的16篇手稿中，我们展示了我们的一系列HSP70抑制剂通过抑制溶酶体和蛋白酶体来靶向癌细胞，并通过导致错误折叠的客户蛋白在不可溶的聚集体中积累而诱导细胞死亡，从而导致蛋白抑制毒性。我们使用蛋白质组学鉴定了十几个新的HSP70客户蛋白，其中包括三个与黑色素瘤高度相关的蛋白：FAK、STAT3和突变的BRAF。我们还表明，HSP70抑制剂还导致HSP90客户蛋白的不溶性、聚集和失活，这是因为HSP70是HSP90的专有辅助伴侣。我们发表了第一个与HSP70细菌同源物DNAK的底物结合结构域结合的HSP70抑制剂的晶体结构。最后，我们揭示了我们的抑制剂的一个全新的作用机制：它们与HSP70中一个新的变构口袋结合，并抑制该蛋白在开放(ATP结合)和闭合(底物结合)构象之间的构象循环，从而抑制HSP70的功能。在这次修订的更新中，墨菲和乔治实验室与一位黑色素瘤专家(Weeraratna)一起评估了HSP70抑制对黑色素瘤生长、转移的疗效，以及与其他黑色素瘤疗法(BRAF抑制剂和免疫检查点抑制剂)的合作。我们要求这个富有成效和协作的团队为我们的新型HSP70抑制剂系列提供6-10年的支持。

 DESCRIPTION (provided by applicant): Malignant melanoma is a devastating tumor for which new therapeutic options are needed. Despite therapeutic successes with BRAF and MEK inhibitors, resistance to these compounds is a major hurdle. Similarly, immune blockade therapies are effective, but only in a subset of populations; therefore, ways to enhance the success of immune surveillance therapies is a significant unmet clinical need. Inhibition of heat shock proteins has been an attractive avenue for melanoma, in particular because the inhibition of heat shock proteins can target cancer through multiple independent pathways, regardless of the driver oncogene(s). HSP70 inhibitors represent a new and exciting class of compounds that have shown significant pre-clinical promise for melanoma. Non-transformed melanocytes express little to no HSP70, while tumor cells express up to 100-fold higher levels, thereby providing a unique therapeutic window for the use of these inhibitors. This renewal application seeks to extend the analysis by the Murphy laboratory at The Wistar Institute with the George laboratory at the Perelman School of Medicine at the University of Pennsylvania on a novel series of HSP70 inhibitors that were discovered jointly by these laboratories. In the sixteen manuscripts published in the past funding period we showed that our series of HSP70 inhibitors target cancer cells by inhibiting the lysosome and proteasome, and that they induce cell death by causing misfolded client proteins to accumulate in insoluble aggregates, leading to proteostatic toxicity. We used proteomics to identify a dozen new HSP70 client proteins, including three with high relevance to melanoma: FAK, STAT3 and mutant BRAF. We also showed that HSP70 inhibitors also cause insolubility, aggregation and inactivation of HSP90 client proteins, due to the fact that HSP70 is an obligate co-chaperone for HSP90. We published the first crystal structure of an HSP70 inhibitor bound to substrate-binding domain of the bacterial orthologue of HSP70, DnaK. Finally, we uncovered a completely novel mechanism of action of our inhibitors: they bind to a novel allosteric pocket in HSP70, and inhibit the conformational cycles of this protein between open (ATP bound) and closed (substrate-bound) conformations, thereby inhibiting HSP70 function. In this revised renewal, the Murphy and George laboratories are joined by an expert in melanoma (Weeraratna) to assess the efficacy of HSP70 inhibition on melanoma growth, metastasis and cooperation with other melanoma therapies (BRAF inhibitors and immune checkpoint inhibitors). Support is requested for years 6-10 from this productive and collaborative team, on our novel series of HSP70 inhibitors.