Department of Oncology, Sidney Kimmel Comprehensive Cancer Center (SKCCC), Johns Hopkins University, Baltimore, Maryland, USA.
Department of Pharmacology and Molecular Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Prostate. 2023 Nov;83(15):1470-1493. doi: 10.1002/pros.24606. Epub 2023 Aug 9.
The quinoline-3-carboxamide, Tasquinimod (TasQ), is orally active as a maintenance therapy with an on-target mechanism-of-action via allosteric binding to HDAC4. This prevents formation of the HDAC4/NCoR1/HDAC3 complex, disrupting HIF-1α transcriptional activation and repressing MEF-2 target genes needed for adaptive survival signaling in the compromised tumor micro environment. In phase 3 clinical testing against metastatic castration-resistant prostate cancer(mCRPC), TasQ (1 mg/day) increased time-to-progression, but not overall survival.
TasQ analogs were chemically synthesized and tested for activity compared to the parental compound. These included HDAC4 enzymatic assays, qRT-PCR and western blot analyses of gene and protein expression following treatment, in vitro and in vivo efficacy against multiple prostate cancer models including PDXs, pharmacokinetic analyses,AHR binding and agonist assays, SPR analyses of binding to HDAC4 and NCoR1, RNAseq analysis of in vivo tumors, 3D endothelial sprouting assays, and a targeted kinase screen. Genetic knockout or knockdown controls were used when appropriate.
Here, we document that, on this regimen (1 mg/day), TasQ blood levels are 10-fold lower than the optimal concentration (≥2 μM) needed for anticancer activity, suggesting higher daily doses are needed. Unfortunately, we also demonstrate that TasQ is an arylhydrocarbon receptor (AHR) agonist, which binds with an EC50 of 1 μM to produce unwanted off-target side effects. Therefore, we screened a library of TasQ analogsto maximize on-target versus off-target activity. Using this approach, we identified ESATA-20, which has ~10-fold lower AHR agonism and 5-fold greater potency against prostate cancer patient-derived xenografts.
This increased therapeuticindex nominates ESATA-20 as a lead candidate forclinical development as an orally active third generation quinoline-3-carboxamide analog thatretains its on-target ability to disrupt HDAC4/HIF-1α/MEF-2-dependent adaptive survival signaling in the compromisedtumor microenvironment found in mCRPC.
喹啉-3-甲酰胺，他昔莫芬（TasQ），通过变构结合 HDAC4 作为一种具有靶向作用的维持治疗药物具有口服活性。这可防止 HDAC4/NCoR1/HDAC3 复合物的形成，从而阻止 HIF-1α 的转录激活，并抑制适应不良的肿瘤微环境中存活信号所必需的 MEF-2 靶基因。在针对转移性去势抵抗性前列腺癌（mCRPC）的 3 期临床试验中，TasQ（1mg/天）增加了无进展时间，但未增加总生存期。
对 TasQ 类似物进行了化学合成，并与母体化合物进行了活性比较。这些包括 HDAC4 酶测定、qRT-PCR 和 Western blot 分析，以及针对多种前列腺癌模型（包括 PDX）的体外和体内疗效分析，包括药代动力学分析、AHR 结合和激动剂测定、SPR 分析与 HDAC4 和 NCoR1 的结合、体内肿瘤的 RNAseq 分析、3D 内皮发芽测定和靶向激酶筛选。在适当的情况下使用基因敲除或敲低对照。
在这里，我们证明在该方案（1mg/天）下，TasQ 的血液水平比抗癌活性所需的最佳浓度（≥2μM）低 10 倍，表明需要更高的每日剂量。不幸的是，我们还证明 TasQ 是一种芳基羟化酶受体（AHR）激动剂，其 EC50 为 1μM，可产生不必要的脱靶副作用。因此，我们筛选了 TasQ 类似物文库，以最大限度地提高靶标与脱靶活性。通过这种方法，我们确定了 ESATA-20，其 AHR 激动作用降低了约 10 倍，对前列腺癌患者来源的异种移植物的效力增加了 5 倍。
这种治疗指数的增加将 ESATA-20 作为候选药物，用于开发具有口服活性的第三代喹啉-3-甲酰胺类似物，该类似物保留其靶向能力，可破坏去势抵抗性前列腺癌中受损肿瘤微环境中 HDAC4/HIF-1α/MEF-2 依赖性适应不良的存活信号。
