RohitKumar Heggodu G, Asha Kittur R, Raghavan Sathees C, Advi Rao Gopal M
Department of Biochemistry, Davangere University, Davangere, Karnataka, India.
Cancer Chemother Pharmacol. 2015 Jun;75(6):1121-33. doi: 10.1007/s00280-015-2735-6. Epub 2015 Mar 29.
DNA intercalators are one of the interesting groups in cancer chemotherapy. The development of novel anticancer small molecule has gained remarkable interest over the last decade. In this study, we synthesized and investigated the ability of a tetracyclic-condensed quinoline compound, 4-butylaminopyrimido[4',5':4,5]thieno(2,3-b)quinoline (BPTQ), to interact with double-stranded DNA and inhibit cancer cell proliferation.
Circular dichroism, topological studies, molecular docking, absorbance, and fluorescence spectral titrations were employed to study the interaction of BPTQ with DNA. Cytotoxicity was studied by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assay. Further, cell cycle analysis by flow cytometry, annexin V staining, mitochondrial membrane potential assay, DNA fragmentation, and western blot analysis were used to elucidate the mechanism of action of BPTQ at the cellular level.
Spectral, topological, and docking studies confirmed that BPTQ is a typical intercalator of DNA. BPTQ induces dose-dependent inhibitory effect on the proliferation of cancer cells by arresting cells at S and G2/M phase. Further, BPTQ activates the mitochondria-mediated apoptosis pathway, as explicated by a decrease in mitochondrial membrane potential, increase in the Bax:Bcl-2 ratio, and activation of caspases.
These results confirmed that BPTQ is a DNA intercalative anticancer molecule, which could aid in the development of future cancer therapeutic agents.
DNA嵌入剂是癌症化疗中一个有趣的类别。在过去十年中，新型抗癌小分子的开发引起了极大的关注。在本研究中，我们合成并研究了一种四环稠合喹啉化合物4-丁基氨基嘧啶并[4',5':4,5]噻吩并(2,3-b)喹啉（BPTQ）与双链DNA相互作用并抑制癌细胞增殖的能力。
采用圆二色性、拓扑学研究、分子对接、吸光度和荧光光谱滴定法研究BPTQ与DNA的相互作用。通过进行3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）和乳酸脱氢酶（LDH）测定来研究细胞毒性。此外，通过流式细胞术进行细胞周期分析、膜联蛋白V染色、线粒体膜电位测定、DNA片段化和蛋白质印迹分析，以阐明BPTQ在细胞水平上的作用机制。
光谱、拓扑学和对接研究证实BPTQ是一种典型的DNA嵌入剂。BPTQ通过使细胞停滞在S期和G2/M期对癌细胞增殖产生剂量依赖性抑制作用。此外，BPTQ激活线粒体介导的凋亡途径，表现为线粒体膜电位降低、Bax:Bcl-2比值增加和半胱天冬酶激活。
这些结果证实BPTQ是一种DNA嵌入性抗癌分子，有助于未来癌症治疗药物的开发。
