Paliwal Kumudini, Haldar Paramita, Antharjanam P K Sudhadevi, Kumar Manjuri
Department of Chemical Engineering, Birla Institute of Technology and Science-Pilani, K. K. Birla Goa Campus, Zuarinagar, Goa 403726, India.
Sophisticated Analytical Instrument Facility, Indian Institute of Technology-Madras, Chennai 600 036, India.
ACS Omega. 2022 Jun 13;7(25):21961-21977. doi: 10.1021/acsomega.2c02354. eCollection 2022 Jun 28.
The isolated copper(II) complex [CuL(-phen)]·HO () [HL = -HO-CHC(H)=N-CH-SH-, -phen = 1,10-phenanthroline] was structurally characterized using single-crystal X-ray crystallography. in CHCN at liquid nitrogen temperature displayed a characteristic monomeric X-band electron paramagnetic resonance spectrum having a tetragonal character with = 2.1479 and = 2.0691 and ≈ 18.0 mT and ≤ 3.9 mT, respectively. showed a strong binding affinity toward calf thymus DNA as reflected from its intrinsic binding constant ( = 7.88 × 10 M), and its competitive displacement of ethidium bromide suggested an intercalative DNA-binding mode ( = 1.32 × 10 M). This was confirmed from the viscosity study that showed an increase in the viscosity of DNA with an increasing concentration of . Complex is highly efficient in promoting oxidative and hydrolytic DNA cleavage ( = 1.987 h). showed a strong binding affinity with the carrier protein human serum albumin (HSA) ( = 5.22 × 10 M). A high bimolecular quenching constant = 2.29 × 10 Ms indicated a static quenching mechanism involved in the fluorescence quenching of HSA by . Fluorescence resonance energy transfer theory suggested that the distance ( = 3.52 nm) between and HSA is very close. Molecular docking studies suggested that primarily binds to HSA in subdomain IIA. A protein-ligand interaction profiler was used to visualize hydrophobic, hydrogen bonds, and π-cation interactions between HSA and . A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay using HeLa and MDA-MB-231 cells showed a significant in vitro anticancer activity of (IC 2.63 and 2.68 μM, respectively). Nuclear staining assays suggested apoptotic cell death in HeLa cells treated with . The effect of on the cytoskeletal actin filaments visualized using phalloidin staining showed extensive destruction of actin filaments. Flow cytometric analysis indicated that inhibits the growth of HeLa cells through cell cycle arrest in the S phase. Western blot analysis showed upregulation in the expression of apoptotic marker proteins caspase 3, p53, and Bax. These results collectively indicate that induces apoptosis by promoting DNA damage and has a high potential to act as an anticancer agent.
通过单晶X射线晶体学对分离得到的铜（II）配合物[CuL(-phen)]·H₂O（）[HL = -HO-CH₂C(H)=N-CH₂-SH-，-phen = 1,10 - 菲咯啉]进行了结构表征。在液氮温度下于乙腈中的该配合物显示出特征性的单体X波段电子顺磁共振谱，具有四方特征，g₁ = 2.1479，g₂ = 2.0691，A₁ ≈ 18.0 mT，A₂ ≤ 3.9 mT。从其固有结合常数（K = 7.88 × 10⁵ M⁻¹）可以看出，该配合物对小牛胸腺DNA具有很强的结合亲和力，并且其对溴化乙锭的竞争性取代表明存在插入式DNA结合模式（K = 1.32 × 10⁵ M⁻¹）。粘度研究证实了这一点，该研究表明随着配合物浓度的增加，DNA的粘度增加。配合物在促进氧化和水解DNA裂解方面非常高效（k = 1.987 h⁻¹）。该配合物与载体蛋白人血清白蛋白（HSA）具有很强的结合亲和力（K = 5.22 × 10⁵ M⁻¹）。高的双分子猝灭常数kq = 2.29 × 10¹² M⁻¹s⁻¹表明在配合物对HSA的荧光猝灭中涉及静态猝灭机制。荧光共振能量转移理论表明配合物与HSA之间的距离（r = 3.52 nm）非常接近。分子对接研究表明配合物主要在亚结构域IIA中与HSA结合。使用蛋白质 - 配体相互作用分析器来可视化HSA与配合物之间的疏水、氢键和π - 阳离子相互作用。使用HeLa和MDA - MB - 231细胞进行的3 -（4,5 - 二甲基噻唑 - 2 - 基）- 2,5 - 二苯基四氮唑溴盐测定显示该配合物具有显著的体外抗癌活性（IC₅₀分别为2.63和2.68 μM）。核染色分析表明用该配合物处理的HeLa细胞发生凋亡性细胞死亡。使用鬼笔环肽染色观察到该配合物对细胞骨架肌动蛋白丝的影响表明肌动蛋白丝受到广泛破坏。流式细胞术分析表明该配合物通过使细胞周期停滞在S期来抑制HeLa细胞的生长。蛋白质印迹分析显示凋亡标记蛋白半胱天冬酶3、p53和Bax的表达上调。这些结果共同表明该配合物通过促进DNA损伤诱导细胞凋亡，并且具有作为抗癌剂的高潜力。
