Abstract

Acridine and its derivatives are well known for their DNA binding properties. In this report, we present our findings on evaluating different binding parameters of the interaction of 9-phenylacridine (ACPH) with DNA. Absorption spectroscopic studies including standard and reverse titration, the effects of ionic strength and temperature on titration, and Job plot analysis were done to calculate the binding constant and determine the different thermodynamic parameters and stoichiometry of the binding. Spectrofluorimetry and circular dichroism (CD) spectral titration were also utilized to confirm these findings. The results indicated that ACPH binds to DNA reversibly through non-electrostatic interactions by hydrogen bonding and van der Waals interactions. The binding constant and the number of binding sites were of the order 10³ M^–1 and ≈2, respectively with a binding stoichiometry of 1:4. The binding of ACPH with DNA was spontaneous, exothermic and enthalpy-driven. The extent of uptake of ACPH in B16 melanoma cells was estimated. As this compound absorbs in the UVA region, the effect of treatment with ACPH prior to UVA exposure was assessed to evaluate its phototoxicity in these cells. Our results indicated that the binding to DNA enhanced damage to sensitize cells to killing through apoptosis. Our findings indicated its potential to act as a photosensitizer.

摘要

吖啶及其衍生物以其 DNA 结合特性而闻名。在本报告中，我们介绍了评估 9-苯基吖啶 (ACPH) 与 DNA 相互作用的不同结合参数的发现。吸收光谱研究包括标准滴定和反向滴定、离子强度和温度对滴定的影响以及工作图分析，以计算结合常数并确定结合的不同热力学参数和化学计量。荧光分光光度法和圆二色性 (CD) 光谱滴定也被用来证实这些发现。结果表明ACPH通过氢键和范德华相互作用通过非静电相互作用可逆地与DNA结合。结合常数和结合位点的数量为 10³  M ^–1和 ≈2，分别具有 1:4 的结合化学计量比。ACPH 与 DNA 的结合是自发的、放热的和焓驱动的。估计了 B16 黑色素瘤细胞对 ACPH 的摄取程度。由于该化合物在 UVA 区域吸收，因此评估了在 UVA 暴露之前用 ACPH 处理的效果，以评估其在这些细胞中的光毒性。我们的结果表明，与 DNA 的结合增强了损伤，使细胞对通过细胞凋亡的杀伤敏感。我们的研究结果表明它具有作为光敏剂的潜力。