低光参量肿瘤靶向光动力疗法的免疫效应及其机制

光动力疗法(photodynamic therapy, PDT)是治疗恶性肿瘤的一种有效手段,除了直接杀伤肿瘤细胞、破坏肿瘤血管外,它还可以诱导机体抗肿瘤免疫。增强PDT诱导的抗肿瘤免疫效应对于防止肿瘤复发、控制已转移肿瘤生长有着重要意义,也是近年来肿瘤靶向PDT的研究热点。肿瘤靶向PDT诱导的免疫效应的强弱与各种参数密切相关,如光功率密度、能量密度、光敏剂种类和剂量等。研究表明,低光参量PDT与常规光参量PDT相比可以诱导更强的抗肿瘤免疫效应,有望提高肿瘤靶向PDT的长期疗效。本文对PDT抗肿瘤免疫和低光参量PDT诱导的免疫效应及其机制做一总结,为进一步优化肿瘤靶向PDT治疗方案以提高其抗肿瘤免疫效应和长期疗效提供参考。     

光动力疗法抗肿瘤免疫的研究进展

光动力疗法(photodynamic Therapy,PDT)作为一种新的治疗手段用于人类肿瘤的治疗已有30多年的历史,目前有多国政府批准PDT应用于肿瘤的治疗。近年来,PDT的抗肿瘤免疫成为研究的焦点。笔者就PDT抗肿瘤免疫的研究进展进行综述。     

光动力学疗法诱导抗肿瘤免疫反应研究的进展

恶性肿瘤是以细胞异常增生为特征的常见疾病，早期诊断和及时治疗是降低肿瘤患者死亡率的关键。但恶性肿瘤的早期诊断和有效控制仍是医学界的棘手问题。手术治疗、放射治疗与药物治疗仍是目前治疗恶性肿瘤的常规手段。但这些传统的治疗手段常难以获得理想疗效，医学界仍在不断探索治疗恶性肿瘤的新方法。光动力学疗法（photodynamic therapy，PDT）是逐渐趋向成熟的治疗肿瘤和非肿瘤疾病的一种新手段。在临床上，光动力学疗法及其与传统治疗手段联合应用治疗恶性肿瘤的技术已逐渐被接受。为了有效控制和根治恶性肿瘤，光动力学疗法以及其他传统治疗手段往往在抗肿瘤免疫的参与下，才有可能达到抗局部原发肿瘤、抗转移肿瘤和防止肿瘤复发等理想效果。本文对光动力学疗法诱导抗肿瘤免疫的临床前期研究进展作一综述，并对光动力学疗法诱导的抗肿瘤免疫反应（anti-tumor immune responses）的机制及其作用和影响进行讨论。     

光动力学疗法对肿瘤细胞信号传导通路作用的研究进展

本文通过综述光动力作用对肿瘤细胞信号传导通路影响的研究成果，进一步分析光动力作用抗肿瘤治疗的可能作用机理，对光动力作用的多种可能作用机制深入进行探讨。     

光动力疗法治疗肝癌的进展

光动力疗法作为治疗肝癌的新方法,能直接杀死肝癌细胞,阻断肿瘤的血液供应,调节机体的抗肿瘤免疫机制,有创伤.小、副作用小、疗效显著等优点,尤其适用于患者一般情况尚可但不能手术切除的肝脏肿瘤,可延长患者的生存期,提高生存质量.多次光动力疗法治疗的效果显著优于单次治疗,可在临床推广应用.     

光动力疗法的免疫效应研究进展

光动力疗法(PDT)是治疗肿瘤和非肿瘤性疾病的一种新疗法。研究表明PDT可诱导肿瘤局部微环境变化使其更适于抗肿瘤免疫效应的形成;同时PDT可诱导多种免疫细胞快速浸润至肿瘤局部、活化补体系统以及促使多种细胞因子/化学因子的产生和释放,最终启动机体适应性免疫应答。利用PDT还可以制备肿瘤疫苗。近期基础实验证实PDT与免疫疗法联合可提高其抗肿瘤效果。     

光漂白对光动力疗法选择性的影响以及光漂白的机制

光漂白是光敏剂的重要性质,是光动力疗法治疗中的普遍现象,在光动力疗法治疗肿瘤和血管疾病中有利有弊.笔者总结了国内外文献对不同光敏剂光漂白机制和光漂白对光动力疗法选择性影响的论述.     

肿瘤光动力疗法——作用机制

肿瘤光动力疗法（Photodynamic therapy,PDT）是一种应用于实体肿瘤治疗的新方法。机体被施予光敏剂后,再用特定波长的光照射,光敏剂随之活化,与底物及氧分子作用产生单线态氧及其他活性氧物质,可以直接杀伤肿瘤细胞。此外,其他作用如血管损伤、诱发炎症反应、促进抗肿瘤免疫等亦可导致肿瘤细胞死亡。本文综述了光动力疗法在肿瘤治疗方面的作用及其机制。     

损伤相关分子模式介导ALA光动力增强皮肤鳞癌的免疫原性研究

正光动力疗法(PDT)在直接杀伤肿瘤细胞的同时,迅速募集免疫细胞在肿瘤治疗部位聚集,诱导宿主产生有效的抗肿瘤免疫反应。据悉,5-氨基酮戊酸光动力(5-amininolevilinic acid-photodynamic therapy,ALA-PDT)启动的抗肿瘤免疫应答可能与其促进某损伤相关分子模式(DAMPs)的暴露或释放有关。我们为研究ALA-PDT诱导肿瘤细胞产生的DAMPs对免疫细胞的影响,采用流式细胞术、ELISA观察DC的成熟     

肿瘤光动力杀伤效应与蒙特卡罗光学模拟对比研究

目的:基于光动力的三要素,大量研究通过模拟组织中光、光敏剂和氧的分布来预测光动力疗法对肿瘤的杀伤效应。然而这些模型与真实的肿瘤三维杀伤效应间的关系尚不明确,常用的肿瘤横截面的二维验证方法不足以建立两者间的联系。为此,建立光动力杀伤效应的空间分布数学模型对整个肿瘤进行组织病理学和生物化学进行分析。方法:对光动力治疗3 d后BALB/C裸鼠EMT-6皮下移植瘤(直径约1 cm)进行序列切片(5μm,约700片)。相邻切片分别进行HE、TUNEL和CD31染色以标记肿瘤坏死、凋亡和血管。全视野数字化图像提取后进行空间分布分析和三位重建。同时运用蒙特卡罗方法模拟肿瘤中的光分布,进行相互验证。结果:肿瘤坏死与组织距光源距离呈指数递减关系,而凋亡和新生血管的分布与光分布无明显相关性。凋亡主要分布在肿瘤的下层(3000～4000μm),新生血管主要分布在2 500～3 500μm深度范围内。结论:光分布模型虽然可以预测光动力疗法引起的肿瘤坏死,但不能有效预测其诱导的细胞凋亡和血管生长。提出的小鼠肿瘤光动力杀伤效应模型,对光动力效应进行了详细的组织病理学、生物化学和分子遗传学分析,将有助于优化治疗策略。     

Influence of photodynamic therapy on peripheral immune cell populations and cytokine concentrations in head and neck cancer

BackgroundPhotodynamic therapy (PDT) represents a palliative treatment option for a selected group of patients with head and neck squamous cell carcinoma (HNSCC). PDT induces a local inflammatory reaction with the potential to initiate antitumor immune responses. However, the systemic impact on peripheral immune cells has not been described so far.MethodsHNSCC patients (n = 9) were treated with PDT in a palliative setting. All patients had previously undergone several oncologic treatment regimens. Blood samples were taken before, during and after PDT. Age-matched healthy donors served as control group (NC, n = 15). The frequency and absolute number of T- and B-lymphocytes, CD4⁺CD39⁺ regulatory T-cells (Treg) and NK-cells were measured by 10-color flow cytometry. Serum concentrations of T cell related cytokine panel, including HMGB1, IL-6, IL-10 and perforin were measured by bead array and ELISA.ResultsIn heavily pretreated HNSCC patients, the number and frequency of Treg and NK-cells were increased as compared to NC. PDT induced a further increase of the frequency of Treg and NK-cells in the peripheral blood. Additionally, the serum concentrations of HMGB1, IL-6 and IL-10 showed a significant elevation after treatment with simultaneously decreased perforin levels.ConclusionAlthough PDT is a local treatment regimen, a systemic inflammatory response with altered peripheral immune cell populations and cytokine concentrations is visible. The increased Treg and NK cell numbers after PDT support the hypothesis that PDT may successfully be combined with NK cell or T cell activating immune checkpoint modulators in HNSCC patients to improve HNSCC specific immunity.     

Targeted PDT,a novel way to induce immunoactivating properties and stimulate anti-tumoral immune response: Illustration in human Pancreatic Adenocarcinoma and Peritoneal Ovarian Cancer models

Otherwise, the use of Photodynamic Therapy (PDT), based on the use of a photosensitizer (PS) and a light with a specific wavelength, has already proved its worth and has prompted a growing interest in the field of oncology. The combination of these factors will generate cytotoxic reactive oxygen species capable of inducing cancer cell death and very importantly, to close the tumor-associated vasculature and trigger the host immune system. More specifically, the damage induced by the PDT generates various alarm signals that could be detected by effectors of innate and adaptative immunity. Nevertheless, the effect of PDT on the regulation of the immune system remains poorly investigated. Although PDT appears to be more selective than other cancer treatment procedures, cancers such as pancreatic adenocarcinoma (ADKP) and intraperitoneal ovarian cancers (OVC) are more problematic and, therefore, the PS used must be much more selective for these tumors. Our previous study described the specificity of a new patented PS coupled with folate receptor (FR) and capable of targeting specifically cancer cells which overexpresses FR. In this context, the aim of this study was (i) to evaluate in vitro and in vivo the efficacy of this new-patented photosensitizer on ADKP and ovarian cancer, which expressed FR in 100% of ADKP and OVC or over-expressed in almost 50% of cases and (ii) to analyze the consequences of this treatment on the regulation of the human immune cells (PBMC).For this purpose, we first evaluated the viability and proliferation rate of these two different human cancer cell lines after targeted PDT treatment. We have also evaluated the secretion of cancer cells subjected to PDT, in particular by analyzing the cytokines and the effects of extracellular vesicles (EVs) secreted by the treated cancer cells. We then examined the effect of this secretome on human peripheral blood mononuclear cells (PBMC) to define the profile of the induced immune response. Finally, we have evaluated in vivo the efficacy of this targeted PDT in a humanized SCID mice model of PDAC and OVC, without and with human PBMC reconstitution.We showed that this PS upon illumination could induce cell death of different ovarian tumor and ADKP cell lines. Furthermore, PDT using this new PS seems to favor an activation of the immune response by inducing the secretion of effective cytokines and inhibiting the pro-inflammatory and immunosuppressive ones, as well as releasing EVs prone to activate immune cells. We also showed that PDT can activate CD4+ and CD8+ T cells resulting in a potential immunostimulating process. All the results therefore indicate that PDT treatment with this new PS would not only be effective in rapidly and directly destroying target tumor cells, but would also promote the activation of effective immune response notably by EVs and promote the development of a protective long-term antitumor immune response. Finally, after fractionized PDT protocol, a significant decrease in the tumor volume was noticed in both in vivo models (PDAC and OVC-SCID mice). An induction in the anti-tumoral cytokine IFNγ chaperoned this decrease with a subsequent inhibition in the cytokine TGFβ. An immune response was activated resulting in an increase in NK, CD3 +T cells, and both helper and Cytotoxic T cells. Thereafter, an increase in the expression of the cytokines IFNγ and TNFα were noticed while an inhibition in TGFβ, IL8 and IL10 accompanied this immune response activation. Therefore, our work has shown for the first time that a fractionized PDT protocol using a folate-targeted PDT is effective for treatment of PDAC and Ovarian cancerThese data thus open up good prospects for the treatment of PDAC and micrometastases of intraperitoneal ovarian carcinosis that are currently inoperable.     

Photodynamic therapy,a promising treatment approach for cutaneous infectious granulomas

Cutaneous infectious granulomas are mainly caused by fungi and bacteria. Antibiotics are the primary therapeutic choices for these diseases, but drug-resistant pathogens have become increasingly prevalent. Thus, there is a need to explore novel approaches to treat cutaneous infectious granulomas. Photodynamic therapy (PDT) is widely used as a treatment for various kinds of skin diseases, and evidence has been accumulating that PDT is also effective for the treatment of cutaneous infectious granulomas. In this narrative review, we sought to summarize the recent literature concerning the applications and mechanisms of PDT in the treatment of cutaneous infectious granulomas. Clinical and basic research has demonstrated that PDT is an effective approach in treating fungal infections such as sporotrichosis and chromoblastomycosis. In addition, PDT is also used to treat atypical mycobacterial infections such as Mycobacterium marinum. PDT can significantly shorten the duration of antibiotics treatment, resulting in diminishment of adverse effects. The potential mechanisms of PDT are to kill the pathogens directly or elicit modulatory effects on the immune microenvironments. We conclude that PDT is a promising therapeutic choice for the treatment of cutaneous infectious granulomas.     

Photodynamic therapy in dermatology: Dundee clinical and research experience

Topical photodynamic therapy (PDT) is increasingly accepted and used as a highly effective treatment for superficial non-melanoma skin cancer and dysplasia. We describe the developments in topical PDT for the treatment of skin diseases in our own PDT Centre in Dundee, both clinically and from a research base. Improvements in PDT could be achieved by optimisation of photosensitiser and light delivery, and these goals underpin the aims of our centre. We hope to facilitate the dissemination of use of PDT in dermatology throughout Scotland and outline some of the progress in these areas.     

钙在血卟啉单甲醚-光动力学疗法处理后HeLa细胞中的变化及作用

目的 了解钙离子在血卟啉单甲醚-光动力学疗法(HMME-PDT)处理后HeLa细胞中的变化和作用。方法 Fura-2／AM孵育荧光分光光度计检测细胞质游离钙浓度[Ca^2 】i的变化，MTT法分析PDT及钙离子对HeLa细胞存活率的影响，Western印迹法分析HMME-PDT后HeLa细胞的肌浆／内质网钙泵(SERCA2)蛋白的降解情况。结果 HMME-PDT处理后即刻HeLa细胞内【Ca^2 】i就开始增高，且与PDT剂量成正相关用，BAPTA／AM拮抗【Ca^2 】i的升高可增加HeLa细胞的存活率。同时HMME-PDT可引起SERCA2蛋白的降解。结论 HMME-PDT处理后HeLa细胞内【Ca^2 】i可迅速增高，【Ca^2 】i，升高可能与SERCA2蛋白的降解相关，并可促进HeLa细胞的死亡。     

光动力疗法与热损伤对正常大鼠胃损伤的研究

为了初步探讨ＰＤＴ与热损伤对正常胃损伤作用机制的差异，本实验以血卟啉衍生物及氩离子泵染料激光器为光敏剂及光源，观察了大鼠胃壁在单纯氩离子激光照射和ＰＤＴ时，照射部位的温度及组织学在照射后７２小时和二周的改变。结果：氩离子激光照射组和ＰＤＴ组胃壁温度均高于对照组（Ｐ＜０．０１），但ＰＤＴ组温度均低于３７℃。氩离子激光照射后的胃壁组织在７２小时各层组织均明显出血，炎细胞浸润，组织凝固坏死。电镜下见胶原纤维肿胀，排列紊乱，甚至溶解吸收。二周后损伤部位以纤维瘢痕组织修复。ＰＤＴ组在７２小时胃壁组织也有充血和炎细胞浸润，但仅有轻度组织坏死，损伤深度未超过粘膜下层。电镜下见胶原纤维结构基本正常。二周后损伤部位以组织再生修复，未留瘢痕。结论：ＰＤＴ与氩离子激光组织损伤及修复方式不同，ＰＤＴ不损伤胃粘膜下胶原纤维。     

Enhancing the efficiency of 5-aminolevulinic acid-mediated photodynamic therapy using 5-fluorouracil on human melanoma cells

Background5-Aminolevulinic acid-mediated photodynamic therapy (ALA–PDT) is an effective and noninvasive modality for treatment of several types of non-melanoma skin cancers. This in-vitro study attempted to know whether the killing effect of ALA–PDT on the human melanoma cells (Mel-Rm cell line) could be increased by the presence of 5-fluorouracil (5-FU).MethodsTo evaluate the effect of ALA–PDT in combination with 5-FU on viability of human melanoma Mel-Rm cells, the cells incubated with 5-ALA and 5-FU for 3 h in nontoxic concentrations, and subsequently illuminated with a 630 nm light-emitting diode array. The cells viability and cytotoxicity determined by mitochondrial activity and lactate dehydrogenase assays.ResultsCombination of ALA–PDT and 5-FU (FU–ALA–PDT) showed a considerable growth inhibition according to the results of MTT assay compared to ALA–PDT. The results of LDH assay also showed a cytotoxicity effect in ALA–PDT; however, the FU–ALA–PDT showed no significantly enhancement in cytotoxicity compared to ALA–PDT using LDH assay.ConclusionThe Mel-Rm cells incubation with 5-FU before PDT enhances the efficiency of 5-Aminolevulinic acid-mediated photodynamic therapy.