类黑色素纳米颗粒联合近红外光照射具有良好的抗卵巢癌作用

Natural melanin-based nanoparticles with photothermal/photodynamic activities induce ovarian cancer cell death

目的探讨类黑色素(PDA)纳米的制备、物化表征及其与光热治疗(PTT)/光动力治疗(PDT)协同抗肿瘤效率。方法采用透射电镜(TEM),水合粒径分析及Zeta电位分析分析PDA纳米的形貌、粒径大小,利用近红外激发光(NIR)探究其光热及光动力性能。将卵巢癌细胞分别用全培(Control组)、单纯PDA、PDA+NIR(0.7 W/cm2与1.0 W/cm2)进行处理,进一步采用流式细胞术、细胞毒性试验(CCK-8)、Transwell实验与单侧皮下荷瘤模型评估类黑色素纳米的PTT/PDT协同抗肿瘤作用。结果制备的PDA纳米为-20 mV及100 nm左右的圆球颗粒。在NIR(0.7 W/cm2与1.0 W/cm2)照射下其变化温度值(ΔT)分别约为15℃或30℃,同时可产生大量单线态氧,具有优良的PTT/PDT性能。流式细胞学结果表明:相比于空白组,PDA纳米不会引起卵巢癌细胞活性氧生成及线粒体膜电位变化,PDA联合NIR照射可诱导卵巢癌细胞内活性氧显著上升以及线粒体膜电位下降(P<0.001);且相比较于低功率NIR(0.7 W/cm2)光照组,高功率NIR(1.0 W/cm2)处理的细胞活性氧水平更高、线粒体膜电位下降越显著(P<0.01)。CCK8实验表明:相比于空白组,PDA对肿瘤细胞无明显毒性,PDA联合NIR照射对卵巢癌细胞具有显著杀伤作用(P<0.001),且相比较于低功率NIR(0.7 W/cm2)光照组,高功率NIR(1.0 W/cm2)处理的细胞存活率越低(P<0.001)。Transwell实验表明:相比于空白组,PDA不能抑制卵巢癌细胞的侵袭迁移能力,PDA联合NIR照射能显著抑制卵巢癌细胞的侵袭迁移能力(P<0.001),且相比较于低功率NIR(0.7 W/cm2)光照组,高功率NIR(1.0 W/cm2)处理的卵巢癌细胞侵袭迁移数目越少(P<0.001)。小鼠单侧皮下荷瘤模型表明:相比于生理盐水组和单独的PDA组,PDA联合NIR照射能发挥显著的体内抗肿瘤作用(P<0.001)。结论类黑色素联合近红外光照射具有良好的抗肿瘤效应,是卵巢癌治疗的一种潜在新方法。

Objective To investigate the physicochemical characteristics of natural melanin-like nanoparticles(PDA NPs)and their synergistic anti-tumor efficacy with photothermal and photodynamic(PTT/PDT)therapy.Methods The chemically synthesized PDA NPs were characterized using transmission electron microscope(TEM),dynamic light scattering(DLS)and Zeta potential analysis,and their photothermal and photodynamic properties were assessed with near-infrared excitation light(NIR).The antitumor efficacy of free PDA or PDA combined with NIR irradiation(0.7 and 1.0 W/cm2)was evaluated in ovarian cancer cells using flow cytometry,Cell Counting Kit-8(CCK-8),and Transwell assay and in a mouse model bearing subcutaneous ovarian cancer xenograft.Results The synthesized PDA NPs showed a spherical morphology with diameters around 100 nm and a zeta potential of-20 mV.Upon NIR irradiation at 0.7 and 1.0 W/cm2,the particles underwent temperature changes(ΔT)of about 15 and 30℃,respectively,and produced a large amount of singlet oxygen,demonstrating their excellent PTT/PDT properties.In ovarian cancer cells,treatment with PDA NPs alone did not induce obvious changes in reactive oxygen species(ROS)production or mitochondrial membrane potential(MTP),but when combined with NIR irradiation,these particles caused a significant increase of ROS and a reduction of MTP(P<0.001),and such changes were more prominent with high power NIR(P<0.01).PDA NPs alone showed no obvious cytotoxicity,but the combination of PDA with NIR irradiation produced potent killing effect on ovarian cancer cells(P<0.001),and the effect was much stronger with a high power irradiation(P<0.001).While PDA alone showed no inhibitory effect on tumor cell metastasis,the combined treatment with PDA and NIR irradiation,especially at a high power,significantly suppressed invasion and migration of ovarian cancer cells(P<0.001).In the tumor-bearing mouse model,the combined treatment,but not PDA alone,produced a significant inhibitory effect on tumor growth(P<0.001).Conclusion PDA NPs combined with NIR has a strong anti-tumor effect,suggesting a potential new therapeutic strategy for ovarian cancer.