Sandomenico Annamaria, Di Rienzo Lorenzo, Calvanese Luisa, Iaccarino Emanuela, D'Auria Gabriella, Falcigno Lucia, Chambery Angela, Russo Rosita, Franzoso Guido, Tornatore Laura, D'Abramo Marco, Ruvo Menotti, Milanetti Edoardo, Raimondo Domenico
Institute of Biostructures and Bioimaging (IBB)-CNR, Via Mezzocannone 16, 80134 Naples, Italy.
Center for Life Nano Science@Sapienza, Italian Institute of Technology, Viale Regina Elena 291, 00161 Rome, Italy.
Biomedicines. 2020 Dec 30;9(1):20. doi: 10.3390/biomedicines9010020.
GADD45β/MKK7 complex is a non-redundant, cancer cell-restricted survival module downstream of the NF-kB survival pathway, and it has a pathogenically critical role in multiple myeloma, an incurable malignancy of plasma cells. The first-in-class GADD45β/MKK7 inhibitor DTP3 effectively kills MM cells expressing its molecular target, both in vitro and in vivo, by inducing MKK7/JNK-dependent apoptosis with no apparent toxicity to normal cells. DTP3 combines favorable drug-like properties, with on-target-specific pharmacology, resulting in a safe and cancer-selective therapeutic effect; however, its mode of action is only partially understood. In this work, we have investigated the molecular determinants underlying the MKK7 interaction with DTP3 by combining computational, NMR, and spectroscopic methods. Data gathered by fluorescence quenching and computational approaches consistently indicate that the N-terminal region of MKK7 is the optimal binding site explored by DTP3. These findings further the understanding of the selective mode of action of GADD45β/MKK7 inhibitors and inform potential mechanisms of drug resistance. Notably, upon validation of the safety and efficacy of DTP3 in human trials, our results could also facilitate the development of novel DTP3-like therapeutics with improved bioavailability or the capacity to bypass drug resistance.
GADD45β/MKK7复合物是NF-κB生存途径下游一种非冗余的、癌细胞特异性的生存模块，在多发性骨髓瘤（一种无法治愈的浆细胞恶性肿瘤）中具有致病关键作用。首个同类GADD45β/MKK7抑制剂DTP3在体外和体内均能通过诱导MKK7/JNK依赖性凋亡有效杀死表达其分子靶点的骨髓瘤细胞，且对正常细胞无明显毒性。DTP3兼具良好的类药性质和靶向特异性药理学特性，产生了安全且癌症选择性的治疗效果；然而，其作用模式仅得到部分理解。在这项工作中，我们通过结合计算、核磁共振和光谱方法研究了MKK7与DTP3相互作用的分子决定因素。通过荧光猝灭和计算方法收集的数据一致表明，MKK7的N端区域是DTP3探索的最佳结合位点。这些发现进一步加深了对GADD45β/MKK7抑制剂选择性作用模式的理解，并为耐药性的潜在机制提供了信息。值得注意的是，在人体试验中验证DTP3的安全性和有效性后，我们的结果还可促进开发具有更高生物利用度或能够绕过耐药性的新型DTP3类疗法。
