Biomolecular Interactions and Anticancer Mechanisms of Ru(II)-Arene Complexes of Cinnamaldehyde-Derived Thiosemicarbazone Ligands: Analysis Combining In Silico and In Vitro Approaches

Our
study focuses on synthesizing and exploring the potential of
three N-(4) substituted thiosemicarbazones derived from cinnamic aldehyde,
alongside their Ru(II)-(η6 -p-cymene)/(η6-benzene) complexes. The synthesized compounds were comprehensively
characterized using a range of analytical techniques, including FT-IR,
UV–visible spectroscopy, NMR (1H, 13C),
and HRMS. We investigated their electronic and physicochemical properties
via density functional theory (DFT). X-ray crystal structures validated
structural differences identified by DFT. Molecular docking predicted
promising bioactivities, supported by experimental observations. Notably,
docking with EGFR suggested an inhibitory potential against this cancer-related
protein. Spectroscopic titrations revealed significant DNA/BSA binding
affinities, particularly with DNA intercalation and BSA hydrophobic
interactions. RuPCAM displayed the strongest binding
affinity with DNA (Kb = 6.23 × 107 M–1) and BSA (Kb = 9.75 × 105 M–1). Assessed the cytotoxicity of the complexes
on cervical cancer cells (HeLa), and breast cancer cells (MCF-7 and
MDA-MB 231), revealing remarkable potency. Additionally, selectivity
was assessed by examining MCF-10a normal cell lines. The active complexes
were found to trigger apoptosis, a vital cellular process crucial
for evaluating their potential as anticancer agents utilizing staining
assays and flow cytometry analysis. Intriguingly, complexation with
Ru(II)-arene precursors significantly amplified the bioactivity of
thiosemicarbazones, unveiling promising avenues toward the creation
of powerful anticancer agents.

本研究聚焦于合成三类源自肉桂醛的N-(4)取代氨基硫脲类化合物，并探究其对应的钌(II)-(η6-对伞花烃)/(η6-苯)配合物的应用潜力。所合成的化合物通过一系列分析技术完成全面表征，涵盖傅里叶变换红外光谱（FT-IR）、紫外-可见分光光度法、核磁共振氢谱/碳谱（1H、13C）以及高分辨质谱（HRMS）。我们借助密度泛函理论（DFT）对该类化合物的电子结构与理化性质展开研究，X射线晶体结构验证了DFT分析所揭示的结构差异。分子对接实验预测其具备良好的生物活性，该结果得到后续实验观测的佐证；值得注意的是，针对表皮生长因子受体（EGFR）的对接结果显示，此类化合物对该癌症相关蛋白具有抑制潜力。光谱滴定实验表明，该类化合物与DNA、牛血清白蛋白（BSA）具有显著的结合亲和力，其中尤以DNA嵌入作用与BSA疏水相互作用最为突出。其中配合物RuPCAM与DNA的结合亲和力最强（结合常数Kb=6.23×10^7 M^–1），与BSA的结合常数为Kb=9.75×10^5 M^–1。我们评估了该系列配合物对宫颈癌细胞（HeLa）、乳腺癌细胞（MCF-7与MDA-MB 231）的细胞毒性，结果显示其具备优异的抗肿瘤活性。此外，通过检测MCF-10A正常细胞系，我们对该类配合物的细胞选择性进行了评估。研究发现，活性配合物可诱导细胞凋亡——这是评估其作为抗肿瘤药物潜力的关键细胞过程——该结论通过染色实验与流式细胞术分析得以证实。有趣的是，与钌(II)-芳烃前驱体配位后，氨基硫脲类化合物的生物活性得到显著增强，为开发高效抗肿瘤药物开辟了极具前景的路径。