【作者】 刘芳；

【导师】 刘磊；

【作者基本信息】 四川大学 ， 肿瘤学（专业学位）， 2021， 博士

【摘要】 背景与目的:放疗是恶性肿瘤的主要治疗手段之一,但是部分肿瘤对放射线不敏感,或由于病灶周围正常组织最大耐受剂量的制约而影响了放疗剂量的提高,这些都限制了肿瘤放射治疗的效果。放射增敏剂与放疗同时应用时能提高放射线的生物效应,实现在相同的放疗剂量下获得更好的肿瘤控制,或者以更小的剂量保护正常组织的同时达到同样的治疗效果。放疗增敏是当前放射生物学的重要研究方向,然而能够在临床中达到预期治疗效果且安全性良好的放射增敏剂屈指可数,寻找新的安全有效的放射增敏剂具有重要意义。漆黄素是一种疏水的天然黄酮类化合物,具有抗炎、抗氧化、抗肿瘤等多重生物学活性。初步研究显示漆黄素具有辐射生物效应修饰作用,但其肿瘤放疗增敏作用及机制还有待进一步明确。此外,漆黄素在水中很难分散形成水基制剂也严重束缚了漆黄素的研究与应用,解决这个问题对于推进漆黄素的研究进程至关重要。在本研究中,我们将利用肿瘤学、生物材料学、纳米技术、分子生物学等多学科交叉,通过将漆黄素包载于纳米胶束中解决其在水中分散性差的应用问题,同时在体内外系统评价漆黄素纳米胶束的放疗增敏效果,并利用蛋白质组学技术深入探究其放疗增敏作用的分子机制,以期为临床提供更多的治疗选择。材料与方法:首先,我们制备了漆黄素纳米胶束并对其性能进行表征。利用开环聚合反应合成两亲性嵌段聚合物MPEG-P(CL-ran-TMC),继而采用薄膜分散法将漆黄素装载于MPEG-P(CL-ran-TMC)纳米胶束中。然后运用一系列手段对其性能进行表征,包括应用紫外-可见分光光度法测定漆黄素纳米胶束的包封率、载药量;马尔文激光粒度仪测定纳米胶束的粒径、电位、多分散指数;透射电镜观察其形貌;透析袋法评价漆黄素胶束的体外药物释放特性;以及应用激光共聚焦显微镜和流式细胞术分析肿瘤细胞对漆黄素胶束的摄取作用。第二章节,我们在体外探究了漆黄素纳米胶束的放疗增敏作用。以小鼠结肠癌细胞CT26、小鼠乳腺癌细胞4T1及小鼠正常细胞成纤维细胞L929为研究对象,采用噻唑兰比色法评价空白胶束及漆黄素胶束的细胞毒性,利用平板克隆形成试验拟合细胞存活曲线并计算放射增敏比以分析漆黄素胶束的放射增敏作用。进一步地,我们对漆黄素胶束放射增敏的主要作用途径进行探究。分别利用克隆形成实验评估分次放疗后细胞亚致死性损伤的修复能力;通过流式细胞术检测细胞内活性氧含量、细胞周期分布和细胞凋亡情况;并采用蛋白质免疫印迹实验分析放疗后细胞内损伤修复相关蛋白phospho-ATM,phospho-ATR,及细胞凋亡相关蛋白Bax,Bcl-2的表达水平。在第三章节的体内研究中,我们分别建立了小鼠CT26结肠癌和4T1乳腺癌皮下移植瘤模型,待肿瘤体积长到50 mm~3左右时将小鼠随机分为五组:空白对照组、空白胶束组、漆黄素胶束组、单纯放疗组、漆黄素胶束联合放疗组(第0天,每组6只小鼠)。自第0至10天每天对各组小鼠尾静脉注射给药:空白对照及放疗组注射生理盐水;空白胶束组注射MPEG-P(CL-ran-TMC)空白胶束溶液;漆黄素胶束及联合治疗组注射漆黄素胶束溶液。于治疗第2及第8天尾静脉给药后对放疗组及联合治疗组小鼠分别进行2 Gy放疗。自治疗始,隔日测量各组小鼠体重及肿瘤的长短径。治疗及观察结束后对各组小鼠取血并统一处死、取肿瘤及主要脏器,后续进行肿瘤组织TUNEL及Ki67免疫荧光染色、肿瘤和脏器组织苏木精-伊红染色(hematoxylin-eosin staining,H&E染色)。根据肿瘤体积或重量计算肿瘤生长抑制率,放疗增敏效果的判断采用金正均q值法:q=E(a+b)/Ea+Eb-Ea×Eb,Ea为单用放疗的效果,Eb为单用漆黄素胶束的效果,E(a+b)为联合治疗的效果,若q≥1.15认为两者有协同作用。在第四章节,进一步收集提取经单纯放疗、漆黄素胶束或漆黄素胶束联合放疗处理后的CT26细胞蛋白,利用TMT标记定量蛋白质组学技术,检索差异表达蛋白并进行基因本体注释和京都基因与基因组百科全书(kyoto encyclopedia of genes and genomes,KEGG)通路注释的富集分析、蛋白质相互作用分析,寻找关键差异表达蛋白并对其功能进行验证,以明确漆黄素胶束发挥放疗增敏作用的分子机制。结果:经核磁共振氢谱验证,成功合成MPEG-P(CL-ran-TMC)聚合物。利用薄膜分散法将漆黄素装载于MPEG-P(CL-ran-TMC)纳米胶束中,制备的漆黄素胶束具有粒径小(30±1 nm)、分布均匀(多分散指数0.14±0.02)、包封率高(92.49±0.62%)、缓释的特点,同时解决了漆黄素在水中分散性差的问题,形成静脉注射制剂。此外,与同浓度的游离漆黄素相比,漆黄素胶束在肿瘤细胞中有更多的摄取,生物利用度更高、对细胞活性的抑制作用更强。在体外研究中,平板克隆形成试验的结果证实了漆黄素胶束的放疗增敏作用。对于CT26、4T1及L929细胞,漆黄素胶束的放射增敏比分别是2.30、1.60和1.19。由此可见,漆黄素胶束可选择性增加肿瘤细胞(CT26和4T1细胞)的放射敏感性,且几乎不影响小鼠正常细胞(L929细胞)对放射线的敏感性。以CT26细胞为研究对象,进一步分析漆黄素胶束放疗增敏的主要作用途径。流式细胞术结果显示,漆黄素胶束可显著增加放疗后细胞内活性氧含量(95.48±1.00%vs.46.55±3.09%,P<0.001;平均荧光强度,263319.00±50697.05vs.61267.00±2259.32,P<0.01),加重细胞的放射损伤。将单次6 Gy放射剂量分为间隔数小时的两次(3/3 Gy)或三次(2/2/2 Gy)照射时,由于亚致死性损伤的修复,细胞的存活率增加(修复率分别为1.43和1.62)。而经漆黄素胶束预处理的细胞,分次放疗后细胞修复率明显下降(3/3 Gy放疗时修复率为1.00;2/2/2 Gy放疗时为1.11),即漆黄素胶束抑制了放疗后细胞亚致死性损伤的修复。而且,漆黄素胶束联合放疗组细胞内活化的DNA损伤修复相关蛋白phospho-ATM及phospho-ATR的表达水平均明显低于单纯放疗组,细胞修复DNA双链断裂的能力下降。此外,经过漆黄素胶束预处理,放疗后更多的细胞被阻滞在对放疗更敏感的G2/M期(如放疗后36 h时,两组G2/M期细胞比例为46.32±3.92%vs.26.44±2.61%,P<0.01)。同时,漆黄素胶束可上调放疗后细胞内促凋亡蛋白Bax、下调抗凋亡蛋白Bcl-2的表达水平,漆黄素胶束联合放疗组的细胞凋亡率显著高于单纯放疗组(33.46±3.33%vs.3.94±0.34%,P<0.001)。在建立的小鼠皮下移植瘤模型中,以漆黄素胶束联合放疗组的肿瘤控制效果最佳。在小鼠CT26结肠癌模型中,于治疗后第18天,空白对照、空白胶束、漆黄素胶束、单纯放疗及漆黄素胶束联合放疗组的肿瘤体积分别为1210.74±590.12 mm~3、1209.10±337.79 mm~3、902.75±269.21 mm~3、771.51±333.16mm~3及175.78±37.20 mm~3,漆黄素胶束、单纯放疗及联合治疗的平均肿瘤体积抑制率分别为25.44%、36.28%和85.48%,q值为1.63(q>1.15);空白对照、空白胶束、漆黄素胶束、单纯放疗及漆黄素胶束联合放疗组的瘤重分别为1.92±0.86 g、2.03±0.81 g、1.50±0.46 g、0.99±0.11 g及0.41±0.08 g,以瘤重计算肿瘤抑制率则漆黄素胶束、单纯放疗及联合治疗的平均抑瘤率分别为22.18%、48.47%和78.81%,q值为1.32(q>1.15)。由此可见,漆黄素纳米胶束与放疗协同发挥抗肿瘤作用,增强小鼠结肠癌的放射敏感性。肿瘤组织H&E染色及Ki67,TUNEL免疫荧光染色结果提示,漆黄素胶束联合放疗可更好的抑制肿瘤细胞增殖、诱导细胞凋亡、加剧肿瘤细胞坏死。在小鼠4T1乳腺癌皮下移植瘤模型中,同样观察到漆黄素胶束的放疗增敏效果。另外,小鼠体重变化、血常规及血生化指标、脏器组织H&E染色结果均提示治疗剂量的漆黄素胶束对小鼠无明显毒性作用。利用蛋白质组学技术探究漆黄素胶束放疗增敏作用的分子机制发现,漆黄素胶束联合放疗组中血小板衍生生长因子受体β(platelet-derived growth factor receptor-β,PDGFRβ)的蛋白表达丰度显著低于单纯放疗组(P<0.001),联合治疗组PDGFRβ相对表达量的平均值是单纯放疗组的0.69倍。既往多项研究提示,抑制PDGFRβ的表达和活化可提高肿瘤细胞的放射敏感性。因此,我们猜测漆黄素胶束的放射增敏作用与其对PDGFRβ的调控有关,并利用蛋白质免疫印迹实验分析PDGFRβ及相关信号通路。结果显示,放疗后CT26细胞内PDGFRβ/STAT1/STAT3/Bcl-2通路活化,PDGFRβ,phospho-PDGFRβ,phospho-STAT1及phospho-STAT3的表达上调,抗凋亡蛋白Bcl-2表达增加,而漆黄素胶束可抑制放疗后该通路的活化。为进一步明确PDGFRβ/STAT通路在漆黄素胶束发挥放疗增敏中的作用,我们利用蛋白质免疫印迹实验、克隆形成试验及细胞凋亡检测分析了选择性PDGFRβ抑制剂CP-673451及PDGFRβ的配体血小板衍生生长因子-BB(platelet-derived growth factor-BB,PDGF-BB)联合漆黄素胶束的放射修饰效应。结果表明,CP-673451可增强漆黄素胶束对放疗后PDGFRβ/STAT1/Bcl-2通路活性的抑制,促进细胞死亡,增强漆黄素胶束的放疗增敏作用。而PDGF-BB则削弱漆黄素胶束对放疗后PDGFRβ/STAT3/Bcl-2通路活性的抑制,促进细胞存活,削弱漆黄素胶束的放疗增敏效果。由上述可知,放疗后PDGFRβ/STAT1/STAT3/Bcl-2通路活化促进细胞存活,漆黄素胶束通过抑制该通路活化提高肿瘤细胞的放射敏感性。结论:在本研究中,我们成功制备了粒径小、分布均匀、高包封率、具有缓释作用的漆黄素纳米胶束,打破了漆黄素难溶于水的应用限制,同时漆黄素胶束具有增加细胞药物摄取的优势。体外研究的结果显示,漆黄素胶束通过增加放疗后细胞内活性氧含量、抑制细胞放射损伤修复、诱导细胞周期阻滞在对放疗更敏感的G2/M期、促进肿瘤细胞凋亡发挥放疗增敏作用。进一步分析后发现,放疗后细胞内PDGFRβ/STAT1/STAT3/Bcl-2通路活化,漆黄素胶束可抑制该通路活化促进细胞死亡,增加肿瘤细胞的放射敏感性。此外,在建立的小鼠CT26结肠癌和4T1乳腺癌皮下移植瘤模型中,漆黄素胶束同样表现出高效的放射增敏作用,与放疗协同抑制肿瘤进展,且治疗剂量的漆黄素胶束对小鼠无明显毒性作用。总之,漆黄素胶束是一种潜在可行的、高效低毒的放射增敏剂。更多还原

【Abstract】 Background and Purpose:Radiotherapy is one of the main methods for cancer therapy.But some tumors are insensitive to radiation,which is a major obstacle in the development of radiotherapy.Besides,due to the restriction of the maximum tolerated dose of normal tissues around lesions,radical radiotherapy is not feasible in some cases.All these issues affect the therapeutic effect of radiotherapy seriously.When used together with radiotherapy,radiosensitizers could improve the biological effect of radioactive rays to achieve better tumor control under the same radiation dose,or obtain the same therapeutic effect while protecting normal tissues with lower dose of radiation.Currently,radiosensitization is an important part of radiobiology.However,radiosensitizers that could achieve the desired treatment outcomes and have high safety in clinical practice are few and far between.Thus,it is of great significance to find safe and effective radiosensitizers.Fisetin is a hydrophobic plant extract,and belongs to the flavonoids compounds that exert numerous biological activities,including antiinflammatory,antioxidant,and antitumor effects.A primary investigation was made on the modification of radiation effect by fisetin,but its radiosensitization effect and related mechanisms still need to be clarified.Furthermore,fisetin with high hydrophobicity is difficult to dissolve in water,which severely limits its research and application.Solving this problem is critical to accelerate the study on fisetin.In this multi-interdisciplinary study,intersecting by oncology,biomaterials,nanotechnology and molecular biology,fisetin was encapsulated in polymeric micelles to solve the problem of its poor solubility,and the radiosensitization effect of prepared fisetin micelles was systematically evaluated in vivo and in vitro with the expectation of providing more clinical treatment options for patients.Additionally,the mechanisms of fisetin micelles radiosensitization were further analyzed based on proteomic technology.Materials and Methods:First of all,fisetin micelles were prepared and characterized.MPEG-P(CL-ran-TMC),an amphiphilic block copolymer,was synthesized by ring-opening polymerization.Fisetin was then loaded into the MPEG-P(CL-ran-TMC)micelles using a thin-film dispersion method.Subsequently,the properties of prepared fisetin micelles were characterized by a series of methods.Ultraviolet-visible spectrophotometry was applied to determine the encapsulation efficiency and drug loading.The zeta potential,particle size distribution and polydispersity index(PDI)were measured by dynamic light scattering.Transmission electron microscopy was utilized to observe the morphological characteristics.The drug release behavior of the prepared micelles was analyzed using the dialysis bag method in vitro.Moreover,confocal microscopy and flow cytometry were used to detect the uptake of fisetin micelles in cells.The radiosensitization effect of fisetin micelles was explored in vitro in the second section.Firstly,the cytotoxicities of MPEG-P(CL-ran-TMC)micelles and fisetin micelles on mouse colon carcinoma CT26 cells,mouse breast cancer 4T1 cells and L929 mouse healthy fibroblast cells were tested by MTT assay.Adopting the colony-forming assay,the radiosensitization effect of fisetin micelles was then explored by fitting cell survival curves and calculating sensitization enhancement ratios.Afterwards,the main ways functioned in radiation hypersensitivity were investigated.The colony-forming experiment was adopted to evaluate the ability to repair sublethal damage after fractional radiotherapy.Flow cytometric analysis was used to detect the intracellular levels of reactive oxygen species,cell cycle distribution and cell apoptosis.Besides,the expression levels of phospho-ATM,phospho-ATR,Bax and Bcl-2 after radiotherapy were analyzed by western blot assay.To evaluate the radiosensitization effect of fisetin micelles in vivo,mouse CT26and 4T1 cells were inoculated subcutaneously into BALB/c female mice to develop mouse models of colon cancer and breast cancer,respectively.The mice were divided into the control,blank micelles,fisetin micelles,radiotherapy alone and fisetin micelles combined with radiotherapy groups(6 mice per group)by chance as the tumor volume reached about 50 mm~3(day 0).Mice in the control and radiotherapy alone groups were intravenously injected with normal saline,mice in the blank micelles group were injected with blank micelles,those in the fisetin micelles and the combined treatment groups were injected with fisetin micelles daily from day 0 to day10.On days 2 and 8,mice of the radiotherapy and the combined treatment groups were treated with 2 Gy irradiation after tail vein administration.Since the start of treatment,tumor size and mouse weight were measured on alternate days.Whole blood was collected at the end for testing blood routine and biochemical indexes.Then the mice were sacrificed by cervical dislocation method,tumor and organ tissues of each group were harvested.The pathological changes of tumor and organ tissues were observed by hematoxylin-eosin(H&E)staining.Furthermore,the immunofluorescent TUNEL and Ki67 staining were performed on tumor tissues.More importantly,tumor growth inhibition rates were calculated based on tumor volume or tumor weight.Adopting a q-value method to judge the radiation sensitization effect of fisetin micelles:q=E(a+b)/Ea+Eb-Ea×Eb,Ea was the effect of using radiotherapy alone,Eb was the effect of using fisetin micelles alone,E(a+b)was the effect of the combined treatment.If q≥1.15,it was considered that fisetin micelles and radiotherapy had synergistic effect.In the fourth part,the molecular mechanisms of the radiosensitization effect of fisetin micelles were further explored using tandem mass tag(TMT)-based quantitative proteomics.After extracting and collecting proteins from CT26 cells treated with radiotherapy,fisetin micelles or the combined treatment,TMT-based quantitative proteomic analysis was employed to analyze the proteomic differences between different groups.Gene Ontology and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses were performed on the differentially expressed proteins to describe their functions.Afterwards,the interaction network of differentially gene-encoded proteins was constructed and the key differentially expressed proteins were identified.To further understand the possible molecular mechanisms,a series of function verification tests were carried out.Results:As ascertained by ~1H nuclear magnetic resonance spectra,MPEG-P(CL-ran-TMC)copolymer was successfully synthesized.Fisetin micelles were obtained by the thin-film dispersion method.The prepared fisetin micelles were characterized with small particle size(30±1 nm),uniform distribution(PDI 0.14±0.02),high encapsulation efficiency(92.49±0.62%),and sustained release.What is more,fisetin micelles had good dispersibility in water and could be injected intravenously.In addition,fisetin micelles had shown higher bioavailability.Comparing with free fisetin at the same concentration,fisetin micelles enhanced the cellular delivery and increased the inhibition of cellular activity.The radiosensitization effect of fisetin micelles was confirmed by colony-forming assay in vitro.For CT26,4T1 and L929 cells,the sensitization enhancement ratios of fisetin micelles were 2.30,1.60 and 1.19,respectively.It could be seen that fisetin micelles selectively increased the radiosensitivity of tumor cells(CT26 and4T1 cells)and hardly affected the sensitivity of mouse normal cells(L929 cells)to radiation.Taking CT26 cells as research subjects,the main ways functioned in radiation hypersensitivity were further investigated.The flow cytometry results showed that fisetin micelles could significantly increase intracellular levels of reactive oxygen species after radiotherapy(95.48±1.00%vs.46.55±3.09%,P<0.001;mean fluorescence intensity,263319.00±50697.05 vs.61267.00±2259.32,P<0.01)and aggravate radiation-induced damage.When a single radiation dose of 6 Gy split into two equal doses(3/3 Gy)or three equal doses(2/2/2 Gy)administered several hours apart,the survival rates increased due to the repair of sublethal damage(the repair rates were 1.43 and 1.62,respectively).For cells pretreated with fisetin micelles,the repair rates were significantly reduced after fractional radiotherapy(the repair rates were 1.00 and 1.11 after 3/3 Gy and 2/2/2 Gy radiotherapy,respectively).This meant that the fisetin micelles effectively inhibited the repair of sublethal damage after irradiation.The expression levels of phospho-ATM and phospho-ATR in cells treated with fisetin micelles and radiotherapy were significantly lower than those in the radiotherapy alone group.Accordingly,the ability to repair DNA double-strand breaks decreased in the combined treatment group.In addition,more cells in the combined treatment group were blocked in G2/M phase after radiotherapy(for example,the percentage of cells in G2/M phase was 46.32±3.92%in the combined treatment group and 26.44±2.61%in the radiotherapy alone group at 36 hours after radiotherapy).Besides,fisetin micelles could up-regulate the expression of Bax and down-regulate the expression of Bcl-2,and induce cell apoptosis after radiotherapy(33.46±3.33%vs.3.94±0.34%,P<0.001).In the two mouse tumor models,mice in the fisetin micelles combined with radiotherapy groups gained the best tumor control comparing with those in other groups.In the subcutaneous CT26 tumor model,the tumor volume of the control,blank micelles,fisetin micelles,radiotherapy alone and combined treatment groups on the 18th day after treatment was 1210.74±590.12 mm~3,1209.10±337.79 mm~3,902.75±269.21 mm~3,771.51±333.16 mm~3 and 175.78±37.20 mm~3,respectively.The tumor volume inhibition rates of fisetin micelles,radiotherapy alone and combined treatment were 25.44%,36.28%and 85.48%,respectively,and the q value was 1.63(q>1.15).From another perspective,the weight of tumors in the control,blank micelles,fisetin micelles,radiotherapy alone and the combined treatment groups was 1.92±0.86 g,2.03±0.81 g,1.50±0.46 g,0.99±0.11 g and 0.41±0.08g,respectively.The average tumor inhibition rates based on tumor weight of fisetin micelles,radiotherapy alone and combined treatment were 22.18%,48.47%and78.81%,respectively,and the q value was 1.32(q>1.15).These data all suggested a synergy between fisetin micelles and radiotherapy treatment to inhibit tumor growth.Furthermore,the H&E staining and Ki67,TUNEL immunofluorescence staining results of tumor tissues showed that the combination of fisetin micelles and radiotherapy could better inhibit tumor cell proliferation,induce apoptosis,and aggravate tumor cell necrosis.Similarly,the radiosensitization effect of fisetin micelles was also observed in the 4T1 tumor model.In addition,the H&E staining results of organ tissues,as well as blood routine and biochemical examination results indicated that therapeutic dose of fisetin micelles had no obvious toxicity to mice.According to the proteomics technology results,the expression level of platelet-derived growth factor receptor-β(PDGFRβ)in the fisetin micelles combined with radiotherapy group was evidently lower than in radiotherapy alone group,the average abundance of which was 0.69 times that of the radiotherapy alone group(P<0.001).Previous studies had shown that the inhibition of PDGFRβexpression could enhance tumor radiosensitivity.From this,we surmised that fisetin micelles radiosensitization was associated with altered expression of PDGFRβ.Further western blot assays of PDGFRβ-related signaling pathways showed that PDGFRβ/STAT1/STAT3/Bcl-2pathway was activated after radiotherapy,the expression levels of PDGFRβ,phospho-PDGFRβ,phospho-STAT1,phospho-STAT3,as well as Bcl-2 were up-regulated,whereas fisetin micelles suppressed this pathway activity.To clarify the role of PDGFRβ/STAT pathway in the radiosensitization effect of fisetin micelles,the modification of radiation effect by CP-673451(a selective PDGFRβinhibitor)and platelet-derived growth factor-BB(PDGF-BB,a PDGFRβligand)was further evaluated,using western blot assay,colony-forming experiment and flow cytometry.The results indicated that CP-673451 could intensify the inhibitory effect of fisetin micelles on PDGFRβ/STAT1/Bcl-2 pathway activity after radiotherapy,promote cell death and enhance the radiosensitization effect of fisetin micelles.But PDGF-BB could weaken the inhibitory effect of fisetin micelles on PDGFRβ/STAT3/Bcl-2pathway activity after radiotherapy,suppress cell death and weaken the radiosensitization effect of fisetin micelles.That is,the activation of PDGFRβ/STAT1/STAT3/Bcl-2 pathway promoted tumor cell survival after radiotherapy,and fisetin micelles played the role of radiotherapy sensitization by inhibiting this pathway.Conclusion:In this study,we successfully prepared fisetin micelles with features of small particle size,uniform distribution,high encapsulation efficiency,good dispersibility in water,and sustained release,which enhanced cellular delivery of fisetin and made its clinical application possible.The experimental results demonstrated that fisetin micelles could exert radiosensitization effect by increasing intracellular levels of reactive oxygen species,inhibiting radiation damage repair,inducing cell cycle arrest and tumor cell apoptosis.On further analysis,it was noticed that PDGFRβ/STAT1/STAT3/Bcl-2 pathway was activated after radiotherapy,while fisetin micelles could suppress this pathway activity to promote tumor cell death and increase anti-tumor effect.Besides,in the mouse models of colon cancer and breast cancer,fisetin micelles showed efficient radiosensitization effect and therapeutic dose of fisetin micelles had no obvious toxicity.In brief,fisetin micelles was a potentially feasible,high-efficiency and low-toxicity radiosensitizer,which played a radiosensitization effect in vitro and in vivo.更多还原