Cytochalasin D as a potential MAPK family inhibitor for treating triple-negative breast cancer

Cytochalasin D, a potent fungal metabolite, has garnered considerable attention due to its diverse biological activities and potential pharmacological applications. Renowned for its ability to disrupt actin polymerisation, it has been extensively used to elucidate cytoskeletal mechanisms. Alongside, it has also earned interest as a cytotoxic agent in cancer therapy. In the current study, we have employed network pharmacology to identify the specific molecular targets in TNBC. Protein targets of cytochalasin D and related drugs (&gt;0.5 similarity score) were obtained from multiple databases. An intricate network was constructed using Cytoscape software highlighting the extensive interplay between the drugs and protein targets. Further analysis of the network revealed six proteins with high significance in cancer cell progression. Molecular docking and MD simulation data showed stable complexes of cytochalasin D when paired with the members of MAPK family. The findings were confirmed <i>in vitro</i> by western blot analysis. A reduction in protein expression was observed in case of all the four MAPKs making it safe to say that cytochalasin D is very likely an inhibitor of the MAPK family proteins, hence giving an insight about the molecular mechanism of the drug as a chemotherapeutic agent.

细胞松弛素D（Cytochalasin D）是一种强效真菌代谢产物，因其多样的生物学活性与潜在药理应用而受到广泛关注。该物质因能够阻断肌动蛋白聚合而闻名，被广泛用于阐明细胞骨架的作用机制。此外，其作为癌症治疗中的细胞毒剂也备受学界关注。本研究采用网络药理学方法，筛选三阴性乳腺癌（Triple-Negative Breast Cancer, TNBC）中的特异性分子靶点：从多个数据库中获取细胞松弛素D及其相似性评分＞0.5的相关药物的蛋白靶点，并使用Cytoscape软件构建复杂相互作用网络，以展示药物与蛋白靶点间的广泛交互作用。对该网络的进一步分析筛选出6个在癌细胞进展中具有关键意义的蛋白。分子对接与分子动力学（Molecular Dynamics, MD）模拟结果显示，细胞松弛素D与丝裂原活化蛋白激酶（Mitogen-Activated Protein Kinase, MAPK）家族成员可形成稳定复合物。本研究通过体外蛋白质免疫印迹（Western Blot）实验验证了上述发现：4种MAPK家族蛋白的表达水平均出现下调，由此可推断细胞松弛素D极有可能是MAPK家族蛋白的抑制剂，从而揭示了该药物作为化疗药物的分子作用机制。