Study on liposomalization of zinc-coproporphyrin I as a novel drug in photodynamic therapy

Photodynamic therapy (PDT) with a photosensitizer and laser irradiation has been shown to have potential effects in cancer chemotherapy. However, the commercial drug clinically gave many problems due to the poor solubility of the photosensitizer in water and the photosensitivity as an adverse reaction of PDT. We have examined best condition on the liposomalization of Zn-complexed coproporphyrin I (ZnCPI) as novel photosensitizer. The difference of pH in buffer significantly changed the ZnCPI entrapped ratio. The entrapped ratio of ZnCPI in PBS(-) buffer was 10.8+/-0.3%, whereas, these levels in some lactate buffer (below pH 5.0) increased. The change between the molecular form<=>ionic form of ZnCPI was occurred due to the change of the pH of buffer, and the amount of ZnCPI in the liposomal membrane changed. The difference of this level was considered to be contributed by the change of zeta potentials. Next, we examined the effect of the different pH of the buffer in liposomal preparation on the ZnCPI distribution in each tissue after each liposome administration. At 2 and 6h post-injection of ZnCPI liposome (pH 4.6), the ZnCPI concentration in the plasma of Ehrlich ascites carcinoma bearing mice was shown to be higher compared to that in other groups. The ZnCPI concentrations in the tumor after 2 and 6h of ZnCPI liposome (pH 4.6) treatment were shown to be higher than that in other groups. In conclusion, it is considered that the ZnCPI liposome (pH 4.6) had the effective antitumor activity with laser irradiation without the adverse reactions.     

Photocytotoxicity of hypocrellin B (HB) was enhanced by liposomalization in vitro

Hypocrellin B (HB) was encapsulated into a phosphatidylcholine liposome. Encapsulation of HB into liposomes not only improved the delivery of this photosensitizer but also increased its photodynamic efficacy compared to free HB molecules. Liposomal HB showed a higher cellular uptake than free HB as measured by confocal microscopy and was internalized into cultured HeLa cells by caveolar endocytosis, which was lipid-raft-dependent. Cell viability measurements demonstrated that liposomal HB was more phototoxic to HeLa cells than free HB as a result of the higher concentration of intracellular HB delivered by the liposomal formulation. The encapsulation of HB influenced the cell death pathway by an increased rate of necrotic cells after irradiation versus free HB, and a Type II (singlet oxygen) mechanism was responsible for the photocytotoxicity.     

Inorganic nanoparticles for enhanced photodynamic cancer therapy

Photodynamic therapy (PDT) in cancer treatment uses photosensitizers to generate singlet oxygen followed by photoirradiation. The efficacy of PDT is greatly determined by the dosimetry of activation light and the photosensitizer (PS), modulating the photodynamic reaction at depth in diseased tissue. Development of nano-formulated photosensitizer has emerged as a promising field because of the biocompatibility and the accessibility for multi-functionalization of nanoparticles. In this review, we summarize the contemporary progress in use of inorganic nanoparticles for improvement of PDT in cancer therapeutics.     

Water-soluble, core-modified porphyrins as novel, longer-wavelength-absorbing sensitizers for photodynamic therapy

Water-soluble, core-modified 5,10,15, 20-tetrakis(4-sulfonatophenyl)-21,23-dithiaporphyrin (1) and 5,10,15, 20-tetrakis(4-sulfonatophenyl)-21,23-diselenaporphyrin (2) were prepared as the tetrasodium salts by the sulfonation of 5,10,15, 20-tetraphenyl-21,23-dithiaporphyrin (3) and -21, 23-diselenaporphyrin (4), respectively, with sulfuric acid. Compounds 3 and 4 were prepared by the condensation of pyrrole with either 2,5-bis(phenylhydroxymethyl)thiophene (5) or 2, 5-bis(phenylhydroxymethyl)selenophene (6) in propionic acid. The addition of benzaldehyde to 2,5-dilithiothiophene or 2, 5-dilithioselenophene gives 5 or 6, respectively, as a nearly equimolar mixture of meso- and d,l-diastereomers. Careful crystallization of 5 gives a single diastereomer by removing the crystalline product from the equilibrating mixture of diastereomers in solution. Photodynamic therapy (PDT) with 1 has an LD(50) of less than 25 microg/mL against Colo-26 cells in culture and exhibits a lethal dose for 90% or more at concentrations greater than 50 microg/mL. In contrast, PDT with 5,10,15, 20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS(4)) requires concentrations of greater than 100 microg/mL to achieve LD(50). Neither 1 nor TPPS(4) shows significant photoactivity against the murine T-cell line, MOLT-4, above the dark toxicity. Sensitizer 1 shows no toxicity or side effects in BALB/c mice observed for 30 days following a single intravenous injection of 10 mg (9.1 micromol)/kg. Distribution studies show that sensitizer 1 accumulates in the tumors of BALB/c mice bearing Colo-26 or EMT-6 tumors with sensitizer concentration roughly doubling as the dosage of 1 increased from 5 to 10 mg/kg. In vivo studies show that PDT with sensitizer 1 at both 3.25 and 10 mg/kg with 135 J cm(-2) of 694-nm light is effective against Colo-26 tumors in BALB/c mice.     

Alginate-based aerogels as wound dressings for efficient bacterial capture and enhanced antibacterial photodynamic therapy

The development of novel wound dressings, such as aerogels, with rapid hemostasis and bactericidal capacities for pre-hospital care is necessary. To prevent the occurrence of bacterial resistance, antibacterial photodynamic therapy (aPDT) with broad-spectrum antibacterial ability and negligible bacterial resistance has been intensively studied. However, photosensitizers often suffer from poor water solubility, short singlet oxygen (¹O₂) half-life and restricted ¹O₂ diffusion distance. Herein, sodium alginate was covalently modified by photosensitizers and phenylboronic acid, and cross-linked by Ca(II) ions to generate SA@TPAPP@PBA aerogel after lyophilization as an antibacterial photodynamic wound dressing. Afterwards, its photodynamic and bacterial capture activities were intensively evaluated. Furthermore, its hemostasis and bactericidal efficiency against Staphylococcus aureus were assessed via in vitro and in vivo assays. First, chemical immobilization of photosensitizers led to an enhancement of its solubility. Moreover, it showed an excellent hemostasis capacity. Due to the formation of reversible covalent bonds between phenylboronic acid and diol groups on bacterial cell surface, the aerogel could capture S. aureus tightly and dramatically enhance aPDT. To sum up, the prepared aerogel illustrated excellent hemostasis capacity and antibacterial ability against S. aureus. Therefore, they have great potential to be utilized as wound dressing in clinical trials.     

Polyacrylamide nanoparticles as a delivery system in photodynamic therapy

Nanoparticles can be targeted towards, and accumulate in, tumor tissue by the enhanced permeability and retention effect, if sequestration by the reticuloendothelial system (RES) is avoided. The application of nanoparticles in the field of drug delivery is thus an area of great interest, due to their potential for delivering high payloads of drugs site selectively. One area which may prove to be particularly attractive is photodynamic therapy, as the reactive oxygen species (ROS) which cause damage to the tumor tissue are not generated until the drug is activated with light, minimizing generalized toxicity and giving a high degree of spatial control over the clinical effect. In the present study, we have synthesized two types of nanoparticles loaded with photodynamic sensitizers: polylysine bound tetrasulfonato-aluminum phthalocyanine entrapped nanoparticles (PCNP) and polylysine bound tetrasulfonato-aluminum phthalocyanine entrapped nanoparticles coated with a second, porphyrin based, photosensitizer (PCNP-P) to enhance the capacity for ROS generation, and hence therapeutic potential. The mean sizes of these particles were 45 ± 10 nm and 95 ± 10 nm respectively. Uptake of the nanoparticles by human Caucasian colon adenocarcinoma cells (HT29) was determined by flow cytometry and confocal microscopy. Cell viability assays using PCNP-P and PCNP corresponding to the minimum uptake time (<5 min) and maximum uptake time (25 h) demonstrated that these cancer cells can be damaged by light activation of these photodynamic nanoparticles both in the external media and after internalization. The results suggest that, in order to induce photodynamic damage, the nanoparticles need only to be associated with the tumor cell closely enough to deliver singlet oxygen: their internalization within target cells may not be necessary. Clinically, this could be of great importance as it may help to combat the known ability of many cancer cells to actively expel conventional anticancer drugs.     

Design and biological activity of novel stealth polymeric lipid nanoparticles for enhanced delivery of hydrophobic photodynamic therapy drugs

Advances in in vivo stability and preferential tumor uptake of cancer nanomedicine are warranted for effective chemotherapy. Here, we describe a novel nanoformulation using an unconventional polymeric tubule-forming phospholipid, DC_8,9PC. We report that DC_8,9PC transitions to stable vesicles (LNPs) in the presence of PEGylated lipid (DSPE-PEG2000); the resulting DC_8,9PC:DSPE-PEG2000 LNPs efficiently included a hydrophobic PDT drug, HPPH. Remarkably, these LNPs incorporated unusually high DSPE-PEG2000 concentrations; LNP₁₀-HPPH and LNP₂₀-HPPH (10 & 20 mol% PEGylated lipid, respectively) exhibited >90% serum stability at 37?°C. Increased PEGylation in the LNPs correlated with enhanced tumor accumulation in intravenously injected HT29 tumor mouse xenographs. Colon-26 bearing BALB/c mice, intravenously injected with LNP₂₀-HPPH showed superior PDT efficacy and animal survival (no tumor recurrence up to 100 days) as compared to a formulation currently used in clinical trials. Taken together, we present a simple stealth binary lipid nanosystem with enhanced efficiency of tumor accumulation and superior therapeutic efficacy.     

卟啉类光敏药物的研究进展

综述了卟啉类光敏药物的研究进展，着重介绍了近年来在设计与合成具有分子识别功能光敏药物这一领域的研究概况，分别讨论了肽链、糖基及核苷等功能基团修饰的卟啉化合物的合成及其作为光敏药物的探索性研究结果。     

Porphyrin dimers as photosensitizers in photodynamic therapy

Porphyrin dimers 9 with either linkages and possible isomers bis[1-[6,7-bis[2-(methoxycarbonyl)ethyl]-1,3,5,8-tetramethyl-2- vinylporphin-4-yl]ethyl] ether (10) bis[1-[6,7-bis[2-(methoxycarbonyl)ethyl]-1,3,5,8-tetramethyl-4- vinylporphin-2-yl]ethyl] ether (11), and 1-[6,7-bis[2-(methoxycarbonyl)ethyl]-1,3,5,8-tetramethyl-2-vinylporph in- 4-yl]ethyl 1-[6,7-bis[2-(methoxycarbonyl)ethyl]-1,3,5,8-tetramethyl-4-vinylporph in- 2-yl]ethyl ether (12) were synthesized from the corresponding (1-hydroxyethyl)vinyldeuteroporphyrin IX dimethyl esters (Hvd). The pure Hvd isomers 2-(1-hydroxyethyl)-4-vinyldeuteroporphyrin IX dimethyl ester (7) and 4-(1-hydroxyethyl)-2-vinyldeuteroporphyrin IX dimethyl ester (8) were obtained from 2-acetyl-4-(1-hydroxyethyl) deuteroporphyrin IX dimethyl ester (3) and 4-acetyl-2-(1-hydroxyethyl)deuteroporphyrin IX dimethyl ester (4). Porphyrins 3 and 4 were prepared either by partial reduction of 2,4-diacetyldeuteroporphyrin IX dimethyl ester (2) or by oxidation of hematoporphyrin IX dimethyl ester (1) by using tetra-n-propylammonium perruthenate (Prn4N)(RuO4) with N-methylmorpholine N-oxide as an oxidizing agent. The in vivo photosensitizing ability and therapeutic ratios of dimers 9-12 were compared with that of Photofrin II in the SMT-F tumor growing subcutaneously in DBA/2 Ha mice. These dimers were found to have better tumoricidal activity than Photofrin II with reduced skin phototoxicity.     

Dual-responsive supramolecular photodynamic nanomedicine with activatable immunomodulation for enhanced antitumor therapy

A major challenge facing photodynamic therapy(PDT) is that the activity of the immuneinduced infiltrating CD8⁺T cells is subject to the regulatory T lymphocytes(Tregs), leaving the tumor at risk of recurrence and metastasis after the initial ablation. To augment the antitumor response and reprogram the immunosuppressive tumor microenvironment(TME), a supramolecular photodynamic nanoparticle(DACss) is constructed by the host-guest interaction between demethylcantharidin-conjugated β-cy...     

克服肿瘤乏氧的超分子纳米粒的制备及其增强光动力疗效

肿瘤乏氧的微环境使光动力治疗的疗效降低,抑制肿瘤细胞自身呼吸耗氧比增加氧供给更能有效地克服肿瘤乏氧,提高光动力治疗疗效.为了实现这一策略,本研究采用纳米沉淀法制备了装载光敏剂维替泊芬(verteporfin,VER)、耗氧抑制剂阿托伐醌(atovaquone,ATO)及稳定剂聚乙烯吡咯烷酮(PVP)-K30的超分子纳米...     

新型光敏剂光动力治疗耐药胃癌的实验研究

目的研究新型光敏剂DTP介导的光动力学治疗(PDT)对人长春新碱(vincristine,VCR)耐药胃癌细胞SGC7901/VCR的治疗作用,并揭示DTP-PDT与P-gp之间的关系及相关机制。方法 MTT法评价DTP-PDT对SGC7901/VCR细胞的杀伤作用及联合治疗作用;建立耐药细胞裸鼠模型,计算瘤体积,观察治疗效果;流式细胞术检测细胞凋亡及坏死情况;检测DTP-PDT后,细胞内单线态氧(~1O_2)产率;流式细胞术和qPCR技术分别检测MDR1 mRNA和P-gp表达。结果 DTP-PDT对SGC7901/VCR细胞及其裸鼠移植瘤均有明显杀伤作用,细胞死亡方式为凋亡;DTP-PDT后,细胞内~1O_2水平增加;DTP-PDT能够抑制耐药细胞MDR1 mRNA转录和P-gp表达,生育酚(α-tocopherol)可以减弱这种抑制;DTP-PDT与VCR合用对耐药细胞有协同治疗作用,生育酚可以减弱这种协同。结论 DTP-PDT产生的~1O_2可以抑制SGC7901/VCR生长,诱发细胞凋亡,而且能够抑制细胞表面P-gp的过表达,减少化疗药物外排,使DTP-PDT与VCR有协同治疗作用。     

Design and development of dendrimer photosensitizer-incorporated polymeric micelles for enhanced photodynamic therapy

Photodynamic therapy (PDT), which involves systemic administration of photosensitizers (PSs) followed by local photoillumination, is a promising method for the treatment of solid tumors and other diseases. Recently, considerable efforts have been devoted to the development of nanocarriers for the PS delivery with the aim of avoiding non-specific phototoxicity to normal tissues such as the skin. Here, we discuss the biological significance of the use of nanocarrier-encapsulated PSs in PDT. Also, we report our recent achievements on the development of dendrimer photosensitizer-loaded micelles as nanocarriers for PS delivery. We found that our nanocarriers greatly enhanced the PDT efficacy in vitro and in vivo, and also significantly reduced the skin phototoxicity. These results indicate the importance of a development strategy for nanocarriers and their great potential for clinical use. In addition, this review discusses the development of nanocarriers for emerging PDT-related technologies such as photodynamic diagnosis (PDD) and photochemical internalization (PCI).     

The chlorophyll catabolite pheophorbide a as a photosensitizer for the photodynamic therapy

Pheophorbide a is a clorophyll catabolite that recently has drawn the attention of several investigators for its potential in photodynamic therapy. In this review we summarize its photophysical properties, phototoxicity, cellular localization, biodistribution and PDT activity as a free or conjugated molecule.     

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。     

Cationic porphycenes as potential photosensitizers for antimicrobial photodynamic therapy

Structures of typical photosensitizers used in antimicrobial photodynamic therapy are based on porphyrins, phthalocyanines, and phenothiazinium salts, with cationic charges at physiological pH values. However, derivatives of the porphycene macrocycle (a structural isomer of porphyrin) have barely been investigated as antimicrobial agents. Therefore, we report the synthesis of the first tricationic water-soluble porphycene and its basic photochemical properties. We successfully tested it for in vitro photoinactivation of different Gram-positive and Gram-negative bacteria, as well as a fungal species (Candida) in a drug-dose and light-dose dependent manner. We also used the cationic porphycene in vivo to treat an infection model comprising mouse third degree burns infected with a bioluminescent methicillin-resistant Staphylococcus aureus strain. There was a 2.6-log(10) reduction (p < 0.001) of the bacterial bioluminescence for the PDT-treated group after irradiation with 180 J·cm(-2) of red light.     

Phthalocyanine-polyamine conjugates as highly efficient photosensitizers for photodynamic therapy

A series of silicon(IV) phthalocyanines substituted axially with different polyamine moieties have been prepared. Their fluorescence quantum yields (Φ(F) = 0.03-0.08) in N,N-dimethylformamide are low because of reductive quenching by the amino moieties. The values are significantly increased in aqueous media (Φ(F) = 0.12-0.21) as a result of protonation of the amino substituents. All the compounds are highly photocytotoxic against human colon adenocarcinoma HT29 cells and Chinese hamster ovary cells with IC(50) values as low as 1.1 nM. Flow cytometric studies of two selected compounds (2 and 5) against HT29 cells have shown that they induce apoptosis extensively. As shown by confocal microscopy, these two compounds also show high affinity toward the lysosomes, but not the mitochondria, of the cells. Their in vivo photodynamic activity has also been investigated using HT29 tumor bearing nude mice. Both of them can effectively inhibit the growth of the tumor without causing apparent injury to the liver of the mice.     

Initiation of apoptosis by photodynamic therapy using a novel positively charged and water-soluble near infra-red photosensitizer and white light irradiation

Our aim was to investigate the photophysical and photodynamic properties of a new, water-soluble positively charged and chemically stable photosensitizer: tetrahydroporphyrin tetratosylat (THPTS). Absorption, fluorescence and (1)H NMR spectra and the intracellular distribution of THPTS were measured. The apoptosis in choroidal melanoma cells was measured using cell death detection ELISA and caspase-8 activity assay. THPTS-PDT efficiency was studied in Balb/c mice bearing C26 colon carcinoma. Subcutaneously located tumors were irradiated with a white light source at a fluence rate of 100 mW/cm(2). THPTS was administrated 3 h before illumination. The tumoricidal effect was examined 24 h after THPTS-PDT by vital staining with 0.4-ml 1% Evans blue solution, intraperitoneally injected to each mouse. THPTS showed a strong absorption band at 760 nm. Its purity, measured by (1)H NMR, is better than 99%. At 24-h incubation period, CLSM revealed THPTS fluorescence in mitochondria and cell nucleus. THPTS possesses no toxic effect in preincubated CM cells without irradiation, and THPTS-PDT causes efficient apoptosis. THPTS-PDT using white light irradiation at a dose of 480 J/cm(2) caused necrosis with a depth of 8 mm in subcutaneously located C26 colon carcinoma in Balb/c-mice. In accordance with the present results, the THPTS seems to be of interest for further in vivo investigations with broad-band white light sources.     

Exocytosis as a possible mechanism for the secretion of coproporphyrin from a chloroquine-treated yeast

Chloroquine, which is known to be concentrated in intracellular acid vesicles, stimulates the release of porphyrins from yeast. Experiments with normal baker's yeast Saccharomyces cerevisiae and the sec-1 mutant, with suppressed exocytosis, showed that the release of porphyrins was stimulated more in normal yeast than it was in the mutant. It is suggested that chloroquine stimulates the exocytosis of porphyrins.