二氢卟吩e6及其对肿瘤的光动力疗法的研究进展

光动力疗法(photodynamic therapy， PDT)是一种利用光能及活性氧清除肿瘤组织的新兴无侵入性微创光生物活性治疗策略。特定波长的光、光敏剂和活性氧是 PDT 的基础，其中最关键的因素是光敏剂。由于吸光系数大，作用深，体内残留少及安全性高等优点，二氢卟吩类光敏剂受到医学领域的广泛认可。二氢卟吩 e6(chlorin e6， Ce6)作为其中的领军成员，尽管清除肿瘤效能高，但潜在的低靶向性及耐药性也阻碍着应用前景。因此，科研工作者们近年将精力投入到将功能性基团引入到 Ce6 结构中，或使用高新纳米技术，以求提高其肿瘤特异性与药物靶向性，并取得了良好的实验进展。本文就近年来光敏剂的发展史及重要光敏剂 Ce6 对肿瘤的光动力疗法的相关研究进展做一综述。     

叶绿素类光敏剂在光动力抗肿瘤中的研究进展

光动力疗法（PDT）是一种多学科交叉融合发展起来的肿瘤治疗方法,光敏剂（PS）是光动力疗法中的重要作用因素。其中,叶绿素类光敏剂包含叶绿素及其衍生物,具有优良的光物理性质,是一类很有临床应用前景的光敏剂,目前针对叶绿素类光敏剂的基础研究及临床应用研究也正在开展。本文拟就八大叶绿素类光敏剂的特征、临床应用及研究进展进行综述。     

光动力学疗法中光敏剂的研究和展望

光动力学疗法(photodynamic therapy,PDT)是一种独具特点的肿瘤治疗新技术,它是随着光敏剂的发现、发展而逐渐建立和完善的。第1代光敏剂血卟啉衍生物的出现奠定了光动力学疗法临床应用的基础。近年来,多种第2代光敏剂不断涌现,丰富了临床用药的选择,进一步扩展了适应症。国内光动力研究经历一段时间低迷后,也有新型光敏剂进入临床研究,预期国内会再次出现一个光敏剂研究和应用的高潮。本文对目前临床研究的主要光敏剂作一回顾分析和总结,并对未来光敏剂的研究方向进行展望。     

卟啉类化合物抗肿瘤活性研究

卟啉类化合物的光敏疗法具有安全、简便、选择性好、高效、低毒、副作用小等优点。主要的卟啉类光敏剂有血卟啉衍生物、脱镁叶绿酸α及其衍生物、酞菁类化合物。     

新型光敏剂δ-氨基酮戊酸

光动力治疗(Photodynamictherapy,PDT)是指给予药物之后,在一定波长的光照射下,才产生治疗作用的一种新兴的治疗方法。给予光敏感药物之后,肿瘤和癌前病变中富含卟啉,发生强烈的荧光,利用其发出不同强度荧光的方法来诊断肿瘤和癌前病变以及界定邻近正常组织,称为光动力诊断(Photodynamicdiagnosis,PDD)。在光化学反应中,有一类分子,它们只吸收光子并将能量传递给那些不能吸收光子的分子,促其发生化学反应,而本身则不参与化学反应,最终恢复到原先的状态,这类分子称为光敏剂(photosensitizer)。δ-氨基酮戊酸是一种新型的光敏剂,化学名称5…     

2,7,12,18-四甲基-3,8-二(1-甲氧乙基)-13,17-二(3-乙胺基丙基)卟啉衍生物的合成及其光敏活性

目的：寻求作用强、副作用轻的光敏剂。方法：以氯化血红素为原料。结果：合成了一种全新的含氮卟啉衍生物，并测定了在Ｄ２Ｏ中对ＮＡＤＰＨ光氧化力。结论：该化合物的光敏活性高于参比药物ＨＰＤ。提示该化合物为一种有发展前途的肿瘤光动力敏化剂。     

2,7,12,18-四甲基-3,8-二(1-甲氧乙基)-13,17-二(3-乙胺基丙基)卟啉衍生物的合成及其光敏活性

目的 寻求作用强、副作用轻的光敏剂。方法 以氯化血红素为原料。结果：合成了一种全新的含氮卟啉衍生物,并测定了在Ｄ２Ｏ中对ＮＡＤＰＨ光氧化力。结论：该化合物的光敏活性高于参比药物ＨＰＤ。提示该化合物为一种有发展前任的肿瘤光动力敏化剂。     

5氨基酮戊酸在非黑素皮肤肿瘤诊疗中的应用

5-氨基酮戊酸(ALA)作为卟啉类第二代光敏剂,因其分子量小、易于合成、用药易吸收、体内排泄快及光毒反应小等特点而受到国内外学者的广泛研究,为目前实验和临床最常使用的光敏剂.同时 ALA 光动力学疗法(ALA -PDT)和 ALA 光动力学诊断(ALA - PDD)更是由于其低毒性、高选择性、微创及可以重复治疗等特点在临床上得到了广泛的应用与研究.本文主要讨论 ALA 作为光敏剂用以诊断和治疗各种非黑素皮肤肿瘤的原理及应用情况.     

槟榔碱对细胞增殖、凋亡和炎症反应影响的研究进展

目的与方法综合整理并介绍槟榔碱及其衍生物对细胞增殖和凋亡影响的研究历程及新进展。结果与结论槟榔碱及其衍生物通过产生亚硝胺类和活性氧族的广泛作用,对细胞多个靶点的进攻最终产生系统毒性作用,进一步抑制细胞增殖、阻断细胞周期、诱导细胞的凋亡。通过调节多种具有重要作用的细胞因子的表达,影响机体免疫功能并导致炎症反应的发生。对其结构中的某些基团进行修饰可能导致其生物学效应发生改变,为抗肿瘤新药的开发提供新的思路和途径。     

新型水溶性卟啉类光敏剂A1光动力治疗黑色素瘤的实验研究

目的探讨新型水溶性卟啉类光敏剂A1光动力疗法对人黑色素瘤细胞系A375的体外及体内抑瘤效应及其相关机制,为临床应用提供理论依据。方法本研究分为空白对照组、单纯激光照射组、单纯光敏剂组及不同剂量光敏剂的光动力治疗组。MTT法检测光动力疗法对A375细胞增殖的影响。利用激光共聚焦显微镜检测A1在A375细胞中的亚细胞定位。利用Hoechst 33342染色和流式细胞术检测细胞凋亡及坏死情况。检测A1光动力治疗后,A375细胞中活性氧(reactive oxygen species,ROS)含量变化。建立黑色素瘤荷瘤小鼠模型,绘制肿瘤生长曲线,观察治疗效果。结果体外实验表明,单纯给药或光照对肿瘤细胞的生长无或很小影响,而A1-PDT治疗组能明显抑制A375肿瘤细胞增殖。Hoechst 33342染色和流式细胞术结果显示,与对照组比较,A1-PDT治疗组可以明显诱导A375细胞凋亡。与对照组比较,A1-PDT治疗组可以明显增加A375细胞中ROS含量。激光共聚焦显微镜显示化合物A1主要定位在肿瘤细胞的溶酶体中。体内实验显示,光动力疗法可以明显抑制小鼠黑色素瘤皮下移植瘤生长。结论光敏剂A1介导的光动力疗法对黑色素瘤细胞及移植瘤的生长抑制作用明显。光动力疗法以细胞凋亡为主,其机制可能与光敏剂A1定位在肿瘤细胞的溶酶体,增加A375细胞中ROS含量,降低谷胱甘肽(GSH)含量相关。     

Cell death and growth arrest in response to photodynamic therapy with membrane-bound photosensitizers

Photodynamic therapy (PDT) is a treatment for cancer and for certain benign conditions that is based on the use of a photosensitizer and light to produce reactive oxygen species in cells. Many of the photosensitizers currently used in PDT localize in different cell compartments such as mitochondria, lysosomes, endoplasmic reticulum and generate cell death by triggering necrosis and/or apoptosis. Efficient cell death is observed when light, oxygen and the photosensitizer are not limiting ("high dose PDT"). When one of these components is limiting ("low dose PDT"), most of the cells do not immediately undergo apoptosis or necrosis but are growth arrested with several transduction pathways activated. This commentary will review the mechanism of apoptosis and growth arrest mediated by two important PDT agents, i.e. pyropheophorbide and hypericin.     

Porphycenes: facts and prospects in photodynamic therapy of cancer

The photodynamic process induces cell damage and death by the combined effect of a photosensitizer (PS), visible light, and molecular oxygen, which generate singlet oxygen ((1)O(2)) and other reactive oxygen species that are responsible for cytotoxicity. The most important application of this process with increasing biomedical interest is the photodynamic therapy (PDT) of cancer. In addition to hematoporphyrin-based drugs, 2nd generation PSs with better photochemical properties are now studied using cell cultures, experimental tumors and clinical trials. Porphycene is a structural isomer of porphyrin and constitutes an interesting new class of PS. Porphycene derivatives show higher absorption than porphyrins in the red spectral region (lambda > 600 nm, epsilon > 50000 M-(1)cm(-1)) owing to the lower molecular symmetry. Photophysical and photobiological properties of porphycenes make them excellent candidates as PSs, showing fast uptake and diverse subcellular localizations (mainly membranous organelles). Several tetraalkylporphycenes and the tetraphenyl derivative (TPPo) induce photodamage and cell death in vitro. Photodynamic treatments of cultured tumor cells with TPPo and its palladium(II) complex induce cytoskeletal changes, mitotic blockage, and dose-dependent apoptotic or necrotic cell death. Some pharmacokinetic and phototherapeutic studies on experimental tumors after intravenous or topical application of lipophilic alkyl-substituted porphycene derivatives are known. Taking into account all these features, porphycene PSs should be very useful for PDT of cancer and other biomedical applications.     

Comparison of sensitizers by detecting reactive oxygen species after photodynamic reaction in vitro.

The production of reactive oxygen species (ROS) has a crucial effect on the result of photodynamic therapy (PDT). Because of this fact, we examined the ROS formation by means of three porphyrin sensitizers (TPPS(4), ZnTPPS(4) and PdTPPS(4)) and compared their effectivity for induction of cell death in the G361 (human melanoma) cell line. The porphyrins used are very efficient water-soluble aromatic dyes with a potential application in photomedicine and have a high tendency to accumulate in the membranes of intracellular organelles such as lysosomes and mitochondria. Interaction between the triplet excited state of the sensitizer and molecular oxygen leads to the production singlet oxygen and other reactive oxygen species to induce cell death. Production of ROS was investigated by molecular probe CM-H(2)DCFDA. Our results demonstrated that ZnTPPS(4) induces the highest ROS production in the cell line compared to TPPS(4) and PdTPPS(4) at concentrations of 1, 10, and 100 microM and light dose of 1 J cm(-2). We also observed a consequence between ROS production and cell survival. In conclusion, these results demonstrate that photodynamic effect depends on sensitizer type, its concentration and light dose.     

Surfactant-polymer nanoparticles enhance the effectiveness of anticancer photodynamic therapy

Photodynamic therapy (PDT) is a promising treatment modality for cancer. PDT is based on the concept that photosensitizers, when exposed to light of specific wavelength, generate cytotoxic reactive oxygen species (ROS) capable of killing tumor cells. The effectiveness of PDT has been limited in part by the lack of photosensitizers that accumulate sufficiently in tumor cells and poor yield of ROS from existing photosensitizers. In this report, we investigated whether aerosol OT-alginate nanoparticles can be used as a carrier to enhance the therapeutic efficacy of a model photosensitizer, methylene blue. Methylene blue loaded nanoparticles were evaluated for PDT effectiveness in two cancer cell lines, MCF-7 and 4T1. Encapsulation of methylene blue in nanoparticles significantly enhanced intracellular ROS production, and the overall cytotoxicity following PDT. It also resulted in higher incidence of necrosis. Greater effectiveness of nanoparticles could be correlated with higher yield of ROS with nanoparticle-encapsulated methylene blue. Further, treatment of tumor cells with nanoparticle-encapsulated methylene blue resulted in significant nuclear localization of methylene blue while free drug treatment resulted in its accumulation mainly in the endolysosomal vesicles. In conclusion, encapsulation of methylene blue in aerosol OT-alginate nanoparticles enhanced its anticancer photodynamic efficacy in vitro. Increased ROS production and favorable alteration in the subcellular distribution contribute to the enhanced PDT efficacy of nanoparticle-encapsulated photosensitizer.     

Meso-tetrakis(p-sulfonatophenyl)N-confused porphyrin tetrasodium salt: a potential sensitizer for photodynamic therapy

A water-soluble derivative of N-confused porphyrin (NCP) was synthesized, and the photodynamic therapeutic (PDT) application was investigated by photophysical and in vitro studies. High singlet oxygen quantum yield in water at longer wavelength and promising IC(50) values in a panel of cancer cell lines ensure the potential candidacy of the sensitizer as a PDT drug. Reactive oxygen species (ROS) generation on PDT in MDA-MB 231 cells and the apoptotic pathway of cell death was illustrated using different techniques.     

Phthalocyanines covalently bound to biomolecules for a targeted photodynamic therapy

Photodynamic therapy (PDT) is a relatively new cytotoxic treatment, predominantly used in anticancer approaches, that depends on the retention of photosensitizers in tumor and their activation after light exposure. This technology is based on the light excitation of a photosensitizer which induces very localized oxidative damages within the cells by formation of highly reactive oxygen species, the most important being singlet oxygen. Many photo-activable molecules have been synthesized such as porphyrins, chlorins and more recently phthalocyanines which present a strong light absorption at wavelengths around 670 nm and are therefore well-adapted to the optical window required for PDT application. However, the lack of selective accumulation of these photo-activable molecules within tumor tissue is a major problem in PDT, and one research area of importance is developing targeted photosensitizers. Indeed, targeted photodynamic therapy offers the advantage to enhance photodynamic efficiency by directly targeting diseased cells or tissues. Many attempts have been made to either increase the uptake of the dye by the target cells and tissues or to improve subcellular localization so as to deliver the dye to photosensitive sites within the cells. The aim of this review is to present the actual state of the development of phthalocyanines covalently conjugated with biomolecules that possess a marked selectivity towards cancer cells; for some of them their photophysical properties and photodynamic activity will be presented.     

Chain-dependent photocytotoxicity of tricationic porphyrin conjugates and related mechanisms of cell death in proliferating human skin keratinocytes

Photodynamic therapy (PDT) is a poor treatment option for nodular basal cell carcinomas and squamous cell carcinomas. As a result, the search for new photosensitizers with better effectiveness is of current interest. The photocytotoxicity of conjugates (P-R) of a water-soluble tri-cationic porphyrin (P-H) having similar efficiency of production of singlet oxygen, the PDT cytotoxin, has been assessed in vitro. Links between uptake, intracellular localization, photooxidative stress, photocytotoxicity and ability to induce programmed cell death are established. Conjugates bearing methyl (P-Me), Di-O-isopropylidene-(-d-galactopyranosyl (P-OGal) or N,N′-dicyclohexylureidooxycarbonyl (P-DDC) chains are efficiently taken-up by proliferating NCTC 2544 keratinocytes. The relative order of photocytotoxicity is P-OGal >P-DDC = P-Me ? P-H. The photocytotoxic potential of P-Me, P-OGal and P-DDC equals that of endogenous protoporphyrin IX induced by δ-aminolevulinic acid or its esters, the pro-drugs currently employed for PDT of skin lesions. Microfluorometry shows that P-Me, P-OGal, and P-DDC localize in endocytotic or pinocytotic vesicles but not in mitochondria or nucleus. Absence of annexin V binding, caspase activation or chromatin condensation suggests that cell photosensitization by P-R does not induce apoptosis. On the other hand, P-OGal photocytotoxicity correlates with appearance of multiple vesicles that have hallmarks of autophagy compartments, being decorated with the marker LC3 in cells transfected with an expression vector encoding GFP-LC3. p38 and JNK phosphorylation and inhibition of ERK1/2 phosphorylation suggest close relationship between mortality of NCTC 2544 keratinocytes and MAPK pathway impairment. Given their potentially easy formulation, water-soluble P-R are promising powerful photosensitizers for PDT of skin lesions.     

Phototoxic effect of TPPS4 and MgTPPS4 on DNA fragmentation of HeLa cells

Photodynamic therapy (PDT) is an alternative method of tumour treatment. It is based on a photochemical reaction of a photosensitizer, irradiation, and O₂ which converts to cytotoxic ¹O₂ and other forms of reactive oxygen species (ROS). The comet assay (also called single-cell gel electrophoresis, SCGE) is a sensitive, simple and quantitative technique for detection of DNA damage. In our study we investigated the phototoxicity of the two porphyrin photosensitizers, TPPS4 and MgTPPS4, on HeLa cells. Three different radiation doses and six different concentrations of the photosensitizers were used. Our results show that the DNA of the cells treated with the TPPS₄ and MgTPPS₄ at the concentrations higher than 5 μM was highly fragmented indicating a strong phototoxic effect resulting in a cell apoptosis. On the base of our results we can hypothesize that even the irradiation dose of 1 J cm⁻² is sufficient enough to provoke the DNA fragmentation.     

Improvement of tumor localization of photosensitizers for photodynamic therapy and its application for tumor diagnosis

Photodynamic therapy (PDT) and photodynamic diagnosis of cancer are widely used in clinical fields. These are performed using photosensitizers. Many metalloporphyrin-related compounds have been developed as photosensitizers for use in PDT, and these tumor localization ability have been improved in recent research. Moreover, the precursor of porphyrin 5-aminolevulinic acid is used in fluorescence diagnosis using its tumor localization ability. In this review, these applications of photosensitizers in cancer therapy and diagnosis are summarized.