Abstract：
Kirsten rat sarcoma virus protein (KRAS) is a protein that plays a central role in signal transduction using extracellular signal regulated kinase (ERK) and mitogen activated protein kinase (MAPK) cellular signaling pathway. KRAS is a frequently mutated oncogene and plays a pivotal role in tumor initiation and progression. Hotspot mutations on codon 12, 13 and 61 in KRAS are well-known for their role in drug resistance and non-hotspot mutations also play a significant part in contributing to resistance mechanisms. The understanding of how these non-hotspot mutations might affect the signal transduction of KRAS and their contribution towards drug resistance is understudied. Here we provide structural insights into the interaction of non-hotspot KRAS mutants with GTP (the native ligand) using a molecular docking and molecular dynamics simulation approach. Extensive molecular docking and simulation studies suggest that non-hotspot mutations (E31D and E63K) show stable interaction with native ligand using all five trajectories, as evidenced by root mean square of distance (RMSD), root mean square of fluctuation (RMSF), radius of gyration (RoG), coulomb short-range energy and MMGBSA analysis. These results suggest that non-hotspot mutations do not undermine the oncogenic nature of KRAS. This observation is consistent with previous findings where overexpressing E31D and E63K mutations share phenotypic features with G12D and G13D transfected cells, including increased proliferative capacity, actin cytoskeleton organization, and migration rates. We further test whether FDA-approved KRAS inhibitors sotorasib and adagrasib successfully inhibit the E31D and E63K mutants. Results suggest that these two non-hotspot mutants can be inhibited by both drugs with following trend of structural stability (E31D > E63K > wild-KRAS > Q61H > G12C). Based on sharp coherence in trajectories between wild KRAS and non-hotspot mutants, it is suggested that these novel mutants do not contribute to drug resistance mechanism. Overall, we provide a comprehensive understanding of the impact of non-hotspot mutations on KRAS and their potential as targets for effective cancer therapies.Communicated by Ramaswamy H. Sarma.
摘要：
Kirsten大鼠肉瘤病毒蛋白（KRAS）是一种在使用细胞外信号调节激酶（ERK）和丝裂原活化蛋白激酶（MAPK）细胞信号传导途径的信号转导中起核心作用的蛋白。KRAS是一种经常突变的癌基因，在肿瘤发生和发展中起着关键作用。KRAS中密码子12、13和61上的热点突变因其在药物抗性中的作用而众所周知,并且非热点突变在促成抗性机制中也起重要作用。对这些非热点突变如何影响KRAS的信号转导及其对耐药性的贡献的理解尚未得到充分研究。在这里，我们使用分子对接和分子动力学模拟方法提供了非热点KRAS突变体与GTP（天然配体）相互作用的结构见解。广泛的分子对接和模拟研究表明，使用所有五个轨迹，非热点突变（E31D和E63K）显示与天然配体的稳定相互作用，如距离均方根(RMSD)所示，波动均方根(RMSF)，回转半径(RoG),库仑短程能量和MMGBSA分析。这些结果表明，非热点突变不会破坏KRAS的致癌性质。这一观察结果与之前的发现一致，其中过表达E31D和E63K突变与G12D和G13D转染的细胞共有表型特征。包括增加的增殖能力，肌动蛋白细胞骨架组织，和迁徙率。我们进一步测试FDA批准的KRAS抑制剂sotorasib和adagrasib是否成功抑制E31D和E63K突变体。结果表明，这两种药物都可以抑制这两种非热点突变体，其结构稳定性趋势如下（E31D>E63K>野生型KRAS>Q61H>G12C）。基于野生KRAS和非热点突变体之间轨迹的尖锐相干性，这表明，这些新的突变体不有助于耐药机制。总的来说,我们全面了解了非热点突变对KRAS的影响及其作为有效癌症治疗靶点的潜力.由RamaswamyH.Sarma沟通。
