Synthesis and in vitro evaluation of benzo[b]thiophene-3-carboxylic acid 1,1-dioxide derivatives as anticancer agents targeting the RhoA/ROCK pathway

Rho family GTPases regulate cellular processes and promote tumour growth and metastasis; thus, RhoA is a potential target for tumour metastasis inhibition. However, limited progress has been made in the development of RhoA targeting anticancer drugs. Here, we synthesised benzo[<i>b</i>]thiophene-3-carboxylic acid 1,1-dioxide derivatives based on a covalent inhibitor of RhoA (DC-Rhoin), reported in our previous studies. The observed structure-activity relationship (contributed by carboxamide in C-3 and 1-methyl-1<i>H</i>-pyrazol in C-5) enhanced the anti-proliferative activity of the derivatives. Compound b19 significantly inhibited the proliferation, migration, and invasion of MDA-MB-231 cells and promoted their apoptosis. The suppression of myosin light chain phosphorylation and the formation of stress fibres confirmed the inhibitory activity of b19 via the RhoA/ROCK pathway. b19 exhibited a different binding pattern from DC-Rhoin, as observed in molecular docking analysis. This study provides a reference for the development of anticancer agents targeting the RhoA/ROCK pathway.

Rho家族GTP酶（Rho family GTPases）调控细胞生理过程，可促进肿瘤生长与转移，因此RhoA是肿瘤转移抑制的潜在靶点。然而当前靶向RhoA的抗癌药物开发进展有限。本研究基于我们此前报道的RhoA共价抑制剂DC-Rhoin，合成了苯并[b]噻吩-3-羧酸1,1-二氧化物衍生物。研究发现的构效关系（由C-3位的羧酰胺基与C-5位的1-甲基-1H-吡唑基团贡献）可增强该类衍生物的抗增殖活性。化合物b19可显著抑制MDA-MB-231细胞的增殖、迁移与侵袭，并促进其凋亡。肌球蛋白轻链磷酸化水平的下调以及应力纤维形成的抑制，证实了b19可通过RhoA/ROCK通路发挥抑制活性。分子对接分析显示，b19与DC-Rhoin的结合模式存在差异。本研究可为靶向RhoA/ROCK通路的抗癌药物开发提供参考。