miR-124靶向STAT3改善脑恶性胶质瘤细胞辐射敏感性

目的 研究miR-124在放射敏感及耐受的脑恶性胶质瘤细胞LN229和LN229R中的表达以及miR-124对细胞放射敏感性的影响,并深入探讨miR-124调控LN229R细胞放射敏感性的作用机制。方法 将miR-124模拟物（miR-124）及阴性对照（miR-NC）,STAT3过表达质粒（STAT3）及pcDNA3.1质粒（pcDNA）单独或共转染到放射抵抗的胶质瘤细胞LN229R中。qRT-PCR检测LN229和LN229R细胞中miR-124的表达;克隆形成实验分析不同放射剂量下LN229R细胞的生存率以及敏感性相关参数值;流式细胞术分析LN229R细胞的凋亡情况;生物信息学预测miR-124和STAT3的靶向关系,并利用双荧光素酶报告分析加以验证;Western blot分析STAT3的蛋白表达水平。结果 与LN229组（1.02±0.09）相比,miR-124在LN229R细胞中的表达水平（0.32±0.03）显著降低,差异有统计学意义（t=12.780,P<0.05）;与miR-NC组（0.95±0.06）相比,转染miR-124模拟物可促进LN229R细胞中miR-124的表达（4.02±0.39）（t=13.476,P<0.05）;8 Gy照射条件下,miR-124过表达组癌细胞的生存率（0.003±0.000 4）显著低于miR-NC组（0.033±0.005 0）（t=5.655,P<0.05）,细胞凋亡率（22.34±2.42）%显著高于miR-NC组（4.69±0.51）%（t=12.361,P<0.05）;STAT3是miR-124的靶基因;外源回补STAT3可逆转miR-124对LN229R细胞生存的抑制作用。结论 miR-124通过靶向STAT3改善LN229R细胞的放射敏感性。     

The effect of photodynamic therapy on head and neck squamous cell carcinoma cell lines using spirulina platensis with different laser energy densities

BackgroundConsidering the anti-cancer properties of spirulina platensis (S. platensis), we aimed to investigate the effectiveness of this algae as a novel natural photosensitizer for photodynamic therapy (PDT) against oral and hypopharyngeal cancer cells. The appropriate laser energy density to apply during PDT was also determined.Methods and MaterialsCAL-27, FaDu and HGF cell lines were exposed to S. platensis with concentrations of 0.3 g/l and 0.6 g/l and were irradiated with 635 nm diode laser using 2, 4, 12, and 24 J/cm² energy densities with constant power. MTT assay was performed to investigate cell viability and cytotoxicity after 24 h. The results were analyzed using two-way ANOVA and post hoc Tukey tests (P-value<0.05).Resultssurvival rate in CAL-27 (P-Value<0.001) and FaDu (P-Value<0.001) cell lines were significantly different following irradiation with various laser energy densities. Different concentrations of S. platensis had no significant effect on the viability of CAL-27 cells (P-Value=0.158) and FaDu cells (P-Value=0.072) and showed no significant cytotoxicity against HGF cells, with or without laser.ConclusionS. platensis could be considered as a novel safe and effective natural photosensitizer for cancer PDT with no cytotoxic effect on normal cells. When combined with laser using appropriate energy densities, it has the ability to induce death in oral and hypopharyngeal cancer cell lines.     

Intracellular glutathione levels affect the outcomes of verteporfin-mediated photodynamic therapy in esophageal cancer cells

Photodynamic therapy (PDT) induces cancer cell death by generating reactive oxygen species (ROS). In this process, photosensitizers accumulate in cancer cells irradiated by laser light of a specific wavelength, leading to ROS generation. Verteporfin (VP), a second-generation photosensitizer, is used in PDT for age-related macular degeneration. However, the antitumor effects of VP-PDT remain poorly defined. This study investigated the antitumor effects of VP-PDT on esophageal cancer (EC) cell lines in vitro. Two types of EC cell lines, the KYSE30 cell line, derived from highly differentiated esophageal carcinoma, and the KYSE170 cell line, derived from moderately differentiated carcinoma, were used in this study. VP-PDT exerted effective anticancer effects in both cell lines. Our results revealed that the low-density lipoprotein receptor, albumin receptor, and heme carrier protein-1 in VP uptake were not involved in VP uptake. However, cells rich in intracellular glutathione were resistant to VP-PDT. Our study outcomes suggest that lowering intracellular glutathione via a glutathione synthesis inhibitor or sulfasalazine can increase the effectiveness of VP-PDT-mediated anticancer effects.     

Methylene blue,curcumin and ion pairing nanoparticles effects on photodynamic therapy of MDA-MB-231 breast cancer cell

PurposeThe aim of current study was to use methylene blue-curcumin ion pair nanoparticles and single dyes as photosensitizer for comparison of photodynamic therapy (PDT) efficacy on MDA-MB-231 cancer cells, also various light sources effect on activation of photosensitizer (PS) was considered.MethodIon pair nanoparticles were synthesized using opposite charge ions precipitation and lyophilized. The PDT experiments were designed and the effect of PSs and light sources (Red LED (630 nm; power density: 30 mW cm⁻²) and blue LED (465 nm; power density: 34 mW cm⁻²)) on the human breast cancer cell line were examined. The effect of PS concentration (0–75 μg. mL⁻¹), incubation time, irradiation time and light sources, and priority in irradiation of blue or red lights were determined.ResultsThe results show that the ion pairing of methylene blue and curcumin enhance the photodynamic activity of both dyes and the cytotoxicity of ion pair nanoparticles on the MDA-231 breast cancer cell line. Blue and red LED light sources were used for photo activation of photosensitizers. The results demonstrated that both dyes can activate using red light LED better than blue light LED for singlet oxygen producing.ConclusionNano scale ion pair precipitating of methylene blue-curcumin enhanced the cell penetrating and subsequently cytotoxicity of both dyes together.     

Cytotoxicity of root canal irrigating solutions and photodynamic therapy using curcumin photosensitizer

BackgroundPhotodynamic therapy (PDT) has shown satisfactory antibacterial effects. However, little information regarding the cytotoxicity potential of PDT using curcumin as a photosensitizer (PS) on fibroblasts are found. The aim of this in vitro study was to evaluate the cytotoxicity of root canal irrigating solutions and photodynamic therapy with curcumin PS on the L-929 cell line.MethodsHealthy mouse skin fibroblast cells were distributed into the following 7 experimental groups: G1 – culture medium DMEM (control group); G2 – 0.9% sodium chloride; G3 – 2.5% sodium hypochlorite (NaOCl); G4 – 5% NaOCl; G5 – PDT with curcumin PS at 500 mg/L + blue LED; G6 – PDT with curcumin PS at 750 mg/L + blue LED; and G7 - PDT with curcumin PS at 1000 mg/L + blue LED. All experimental groups which underwent PDT action were submitted to blue LED for 4 min, with a wavelength of 480 nm and energy fluency of 75 J/cm². The cultures were maintained under standard cell culture conditions (37°C, 100% humidity, 5% CO₂). Cell viability analysis was performed using the colorimetric method to evaluate the periods of 6, 24, and 48 h. Data were subjected to the Kruskal–Wallis test, followed by the Dunn test to compare groups and Friedman test to compare periods (α = 0.05).ResultsWhen comparing the periods, no significant differences were observed for any of the experimental groups analyzed (p > 0.05), except for the NaOCl_2.5 group that exhibited higher cell viability at 6 h compared to the period of 48 h (p = 0.0489). In the comparisons of the experimental groups, there were no statistically significant differences between the control group compared to all disinfection protocols, regardless of the period evaluated (p > 0.05), except for the PDT + C₁₀₀₀ group that showed lower cell viability (P < 0.05).ConclusionsPDT with curcumin at 1000 mg/L was cytotoxic on L-929 fibroblast cell culture. However, laser-activated curcumin at a concentration of 500 mg/L presented no influence on L-929 fibroblast cell viability in in vitro conditions.     

Photodynamic process induced by chloro-aluminum phthalocyanine nanoemulsion in glioblastoma

BackgroundGlioblastoma multiforme (GBM) is a tumor characterized by rapid cell proliferation and migration. GBM constitutes the most aggressive and deadly type of brain tumor and is classified into several subtypes that show high resistance to conventional therapies. There are currently no curative treatments for malignant glioma despite the numerous advances in surgical techniques, radiotherapy, and chemotherapy. Therefore, alternative approaches are required to improve GBM treatment.MethodsOur study proposes the use of photodynamic therapy (PDT) for GBM treatment, which uses chloro-aluminum phthalocyanine (AlClPc) encapsulated in a new drug delivery system (DDS) and designed as a nanoemulsion (AlClPc/NE). The optimal dark non-cytotoxic AlClPc/NE concentration for the U87 MG glioma cell model and the most suitable laser light intensity for irradiation were determined. Experimental U87 MG cancer cells were analyzed via MTT cell viability assay. Cellular localization of AlClPc, morphological changes, and cell death via the necrotic and apoptotic pathways were also evaluated.ResultsAlClPc remained in the cytoplasmic region at 24 h after administration. Additionally, treatment with 1.0 μmol/L AlClPc under light irradiation at doses lower than 140 mJ/cm resulted in morphological changes with 50 ± 6% cell death (p < 0.05). Moreover, 20 ± 2% of U87 MG cells underwent cell death via the necrotic pathway. Measurement of Caspase-9 and -3 activities also suggested that cells underwent apoptosis. Taken together, these results indicate that AlClPc/NE-PDT can be used in the treatment of glioblastoma by inducing necrotic and apoptotic cell death.ConclusionsOur findings suggest that AlClPc/NE-PDT induces cell death in U87 MG cells in a dose-dependent manner and could thus serve as an effective adjuvant treatment for malignant glioma. AlClPc/NE-PDT utilizes a low dose of visible light and can be used in combination with other classic GBM treatment approaches, such as a combination of chemotherapy and surgery.     

Tetrahydroporphyrin-tetratosylat (THPTS): A near-infrared photosensitizer for targeted and efficient photodynamic therapy (PDT) of human bladder carcinoma. An in vitro study

BackgroundEfficacy of PDT in muscle-invasive bladder cancer is hampered by low tissue penetration of most photosensitizers by short excitation wavelength. THPTS is excitable at near-infrared (760 nm) allowing tissue penetration up to 15 mm. We examined the cellular effects of THPTS-PDT in human bladder cancer cells.Material and methodsWe used four human transitional carcinoma cell lines, epithelial bladder progenitors (HBLAK) and bladder smooth muscle cells (HBSMC). We used flow cytometry to examine pharmacokinetics of THPTS, confocal laser scanning microscopy to analyze subcellular localization and production of reactive oxidative species (ROS), examined cytotoxicity and cell death pathways (qRT-PCR).ResultsTotal uptake varied between cell lines and was significantly high in HBLAK and HBSMC. Lysosomal localization was mainly seen in cancer cells and HBLAK, while THPTS was distributed throughout the cytoplasm in HBSMC. Significant ROS production was detected 30 min after THPTS-PDT. Growth arrest occurred within 4 h and resulted in apoptotic and necrotic cytotoxicity after 24 h. Cytotoxicity was dose-dependent and specifically high in cancer cells and HBLAK and significantly low in HBSMC.ConclusionTHPTS-PDT induces cellular mechanisms leading to cellular growth arrest, apoptosis and necrosis in human bladder cancer cells. These effects are only partly dependent on the total amount of THPTS uptake and rather dependent on its subcellular compartmentalization. HBSMC are hardly affected by THPTS-PDT confirming tumor specificity and safety. THPTS is a promising new photosensitizer with the unique advantage of deep tissue penetration allowing the treatment of solid tumors and warranting further animal studies.     

Photodynamic therapy using a cytotoxic photosensitizer porphyrus envelope that targets the cell membrane

BackgroundSubcellular localization of a photosensitizer is known to determine the therapeutic efficacy of photodynamic therapy (PDT). Cell membrane is an optimal target that promises an effective treatment outcome.ObjectivesWe previously developed a novel photosensitizer named porphyrus envelope (PE) by combining hemagglutinating virus of Japan envelope (HVJ-E) with lipidated protoporphyrin IX (PpIX lipid). In the current study, the cellular localization of PE and its ability to induce multiple anti-tumor effect were characterized.Materials and MethodsThe localization and uptake of PpIX lipid in cells were evaluated with confocal laser scanning microscopy and a cell-based fluorescent assay, respectively. The ability of PE to suppress the migration and proliferation of cancer cells was assessed using a scratch-wound assay. The synergistic effect of PDT and HVJ-E treatment was evaluated using an in vitro experiment with PC-3 cells.ResultsPE localized along the cell membrane and PpIX lipid accumulated selectively in the prostate cancer cells within 10 min. Also, PE maintained the ability to undergo fusion and induce cancer cell death even after light irradiation at the dose for PDT. Incubation with PE resulted in delayed migratory and proliferative activity of PC-3 cells. PE-mediated PDT was twice as effective when cells were further incubated with PE following PDT.ConclusionsPE allows rapid drug delivery targeting the cell membrane. Because the cytotoxicity of HVJ-E was maintained, synergistic effect of HVJ-E and the photochemical reactions resulted in highly effective killing of prostate cancer cells in vitro and thus represents a promising treatment for prostate cancer.     

Identification and pharmacological modification of resistance mechanisms to protoporphyrin-mediated photodynamic therapy in human cutaneous squamous cell carcinoma cell lines

BackgroundPhotodynamic therapy (PDT) is clinically approved to treat neoplastic skin diseases such as precursors of cutaneous squamous cell carcinoma (cSCC). In PDT, 5-aminolevulinic acid (5-ALA) drives the selective formation of the endogenous photosensitizer protoporphyrin IX (PpIX). Although 5-ALA PDT is clinically highly effective, resistance might occur due to decreased accumulation of PpIX in certain tumors. Such resistance may be caused by any fundamental step of PpIX accumulation: 5-ALA uptake, PpIX synthesis and PpIX efflux.MethodsWe investigated PpIX accumulation and photodynamically induced cell death in PDT refractory SCC-13, PDT susceptible A431, and normal human epidermal keratinocytes (NHEK). Expression of genes associated with cellular PpIX kinetics was investigated on mRNA and protein level. PpIX accumulation and cell death upon illumination were pharmacologically manipulated using drugs targeting 5-ALA uptake, PpIX synthesis or efflux.ResultsThe experiments indicate that taurine transporter (SLC6A6) is the major pathway for 5-ALA uptake in cSCC cells, while being less important in NHEK. Downregulation of PpIX synthesis enzymes in SCC-13 was counteracted by methotrexate (MTX) treatment, which restored PpIX formation and cell death. PpIX efflux inhibitors targeting ABC transporters led to significantly increased PpIX accumulation in SCC-13, thereby fully overcoming resistance.ConclusionsThe results indicate a conserved threshold for PpIX accumulation with respect to PDT-resistance. Cells showed increased viability after PDT at PpIX concentrations below 1.5 nM. Selective uptake of 5-ALA via taurine transporter SLC6A6 in cutaneous tumor cells is novel but unrelated to resistance. MTX can partially abrogate resistance by PpIX synthesis enzyme induction, while efflux mechanisms via ABC transporters seem the main driving force and promising drug targets.     

Effects of photodynamic therapy with talaporfin sodium on squamous cell carcinoma and sarcoma cells

BackgroundPhotodynamic therapy (PDT) uses a photosensitizer and light to destroy abnormal cells. Talaporfin sodium (NPe6) is a second-generation photosensitizer.MethodsWe evaluated the toxic effects of different combinations of laser and NPe6 doses on squamous cell carcinoma (KLN205) and sarcoma (Meth A) cell lines. The cells were incubated with 0, 5, 10, or 30 μg/mL NPe6 for 24 h. The cells were then irradiated with 0, 5, 15, or 30 mW/cm² of laser power, and 0, 1, 5, 10, or 20 J/cm² of laser energy. Cell viability was evaluated after 24 h. We also evaluated the cytotoxic effects of continuous wave or square-wave modulated laser irradiations (2, 5, or 10 Hz, 50% duty) on Meth A cells.ResultsThe median lethal doses of NPe6 against the KLN205 and Meth A cells after treatment at a fluence rate of 15 mW/cm² and a light dose of 20 J/cm² were 18.6 and 5.0 μg/mL, respectively. Meth A cells were more sensitive to PDT than KLN205 cells. There was no significant difference between the effects of continuous wave and square-wave modulated lasers on Meth A cell viability.ConclusionsNPe6 PDT induced cell death in a dose-dependent manner in KLN205 and Meth A cells. More work is required to evaluate the cytotoxic effects of square-wave modulated laser therapy at low light doses.     

Phototoxicity in a laryngeal cancer cell line enhanced by a targeting amphiphilic chlorin photosensitizer

BackgroundPhotodynamic therapy (PDT) has been established in several countries as an alternative therapy for the treatment of various malignancies. This therapy involves the incorporation of a photosensitizer (PS) that is activated by visible light and form reactive oxygen species leading to target cell death by apoptosis or necrosis. Previously, our group has demonstrated that CHL-T (semi-synthesized from chlorophyll a and containing a linked solubilizing group TRISMA^®) presented a pronounced potential to induce death in HeLa cell line after PDT. In the present study, besides confirm the high cytotoxicity in another cell line, we have further investigated the cell death mechanisms caused by CHL-T as a photosensitizer in laryngeal carcinoma cells.MethodsCells were exposed to different concentrations of three photosensitizers, namely, hypericin (HY), unmodified chlorin (CHL) and a synthesized amphiphilic chlorin derivative (CHL-T). PSs accumulation and localization were accessed by fluorescence assays. Photosensitization was induced at 6 J cm⁻² using red LEDs (630 ± 10 nm). Viability was assessed by mitochondrial function (MTT); whereas apoptosis/necrosis was evaluated by fluorescence microscopy and flow cytometry. Expression of pro-apoptotic p53 protein was studied by Western blot.Results and conclusionsAll PS showed similar localization profile in the HEp-2 cells. The use of CHL-T increased the percentage of apoptotic cells and also p53 expression in comparison with the use of HY and CHL as photosensitizers. This study shows a significant effect of CHLT associated with red light (630 ± 10 nm and 18 mW cm⁻²) irradiation on a cancer cell line, indicating the potential of this amphiphilic chlorin in enhancing the therapeutic effectiveness of Photodynamic Therapy (PDT).     

抗VCAM-1单克隆抗体联合光动力疗法治疗大鼠C6脑胶质瘤的研究

目的探讨抗VCAM-1单克隆抗体联合光动力疗法（PDT）对大鼠脑C6胶质瘤生长的抑制作用。方法建立C6脑胶质瘤模型,成瘤动物分4组,即PDT＋VCAM-1抗体组、PDT组、VCAM-1抗体组和对照组。观察各组VCAM-1表达、凋亡指数、大鼠生存时间、肿瘤体积、计算抑瘤率。结果 PDT组和VCAM-1抗体组均能抑制肿瘤生长,PDT＋VCAM-1抗体组的抑制作用更显著。PDT组VCAM-1表达增高明显。抗体组VCAM-1表达受到明显抑制。结论 PDT治疗后给予抗VCAM-1单克隆抗体既抑制VCAM-1表达增加,又抑制新血管生成,从而更有效地抑制胶质瘤生长,延长生存时间。     

Effect of SWEEPS and PIPS techniques on dye extrusion in photodynamic therapy procedure after root canal preparation

AimThe aim of this study is to measure and compare the amount of apical extrusion of the methylene blue as photosensitizer using Laser-activated irrigation(LAI) techniques (SWEEPS, PIPS) and photodynamic therapy (PDT).Materials and methods40 single-rooted premolar teeth were selected and their root canals were cleaned and prepared. The photosensitizer, Methylene blue (MB), was used as dye which applied inside the root canals and the access cavities. Then the teeth were randomly allocated to 4 groups. Different techniques (SWEEPS, PIPS, PDT) were used in 3 groups. One group received no activation. Data related to the concentration of the extruded methylene blue was measured using ultraviolet and visible (UV–Vis) absorption spectroscopy. Absorption peak intensity of MB in the wavelength of 668 nm was considered as the concentration index according to Beer Lambert law. Taking into account the normal distribution of this data, one-way ANOVA analysis was used to evaluate the effects of the independent variables on the amount of apical extrusion of the irrigant.ResultsBased on the results of ANOVA analysis, there was no significant difference between the amounts of apical extrusion of MB between different groups (p = 0.628)ConclusionUsing SWEEPS and PIPS techniques, despite diffusion of the photosensitizer, didn't lead to any difference in the amount of apical extrusion. Therefore, these LAI techniques can be used safely for root canal irrigation.     

Sub-additive effects of photodynamic therapy combined with erlotinib for the treatment of epidermoid carcinoma: An in vitro study

BackgroundPhotodynamic therapy (PDT) is an antitumour treatment that employs the combination of a photosensitive compound, oxygen and visible light. To improve the antitumour activity of PDT, the present study used the strategy of combining PDT with erlotinib (ERL), a drug frequently used in the treatment of epidermoid carcinoma.MethodsAn MTT cell viability assay was used to evaluate the cytotoxicity of PDT combined with ERL on A431 epidermoid carcinoma cells in vitro. This study evaluated the cytotoxicity of the following treatments: red laser irradiation (660 nm) at different power densities (1.25–180 J/cm²), the photosensitizer methylene blue (MB) at concentrations of 0.39–100 μM, PDT (12.5 μM MB and laser power densities from 1.25 to 180 J/cm²), and PDT (12.5 μM MB and a laser density of 120 J/cm²) plus ERL (1 μM).ResultsThe laser power densities that were tested showed no cytotoxicity in A431 cells. MB showed a dose-dependent cytotoxicity. In PDT, an increase in the dose of light resulted in an increase in the cytotoxicity of MB. In addition, there was a sub-additive effect between PDT and ERL compared to the effect of each therapy alone.ConclusionsThe sub-additive effect between PDT and ERL suggests that their combination may be an important strategy in the treatment of epidermoid carcinoma.     

Skin fluorescence following photodynamic therapy with NPe6 photosensitizer

BackgroundThe second-generation photosensitizer NPe6 has strong anti-tumor effects with a much shorter photosensitive period than the first-generation photosensitizer Photofrin. Although photosensitive period has been reduced, skin photosensitivity is still a major side effect of photodynamic therapy (PDT). Therefore, we conducted a prospective study to investigate whether the NPe6 fluorescence intensity in skin after PDT could be measured effectively in human patients to improve the management of a patient's photosensitive period.MethodsThe NPe6 fluorescence measurements using a constructed fluorescence sensing system at the inside of the arm were acquired prior to and 5 and 10 min after NPe6 administration as well as at the time of PDT (4–5 h after administration), at discharge (2 or 3 days after PDT), and at 1 or 2 weeks after PDT. Participants were interviewed as to whether they had any complications at 2 weeks after PDT.ResultsNine male patients and one female patient entered this study. Nine patients were inpatients and one patient was an outpatient. All of the measurements of NPe6 fluorescence in the skin could be obtained without any complications. The spectral peak was detected at the time of discharge (2–3 days after administration) in most cases and it decreased at 1 or 2 weeks after PDT.ConclusionsThe fluorescence of NPe6 in the skin could be detected feasibly using the fluorescence sensing system in human patients. Measuring the relative concentration of NPe6 in the skin indirectly by measuring fluorescence intensity might be useful to predict the period of skin photosensitivity after PDT.     

Photodynamic therapy using methylene blue in lung adenocarcinoma xenograft and hamster cheek pouch induced squamous cell carcinoma

BackgroundPhotodynamic therapy (PDT) is used to treat early proximal bronchial cancer during a flexible bronchoscopy. The technique relies on the excitation of a photosensitizer by an appropriate wavelength, which is delivered into the bronchus in close contact with the tumor.ObjectiveTo assess methylene blue (MB) as a PDT agent for the treatment of respiratory tract cancer in animal models.MethodsMB-induced PDT was performed on 7 subcutaneous NCI-H460 lung adenocarcinoma xenografts in nude mice and 9 induced squamous cell cancer in the hamster cheek pouch model. In mice, PDT was carried out on right-sided tumors after intratumoral injection of methylene blue 1% (w/v) and illumination at 630 nm at 200 J/cm (Diomed PDT 630), with the left tumor used as control (illumination alone or MB alone). The tumoral volume was assessed before and 15 days after PDT.ResultsFourteen xenografts were treated in mice, including seven treated with MB-PDT, producing a 52% mean tumor volume regression (1568 mm³ vs. 544 mm³) compared to seven control cases in which tumor volume increased (p = 0.007; Mann-Whitney test). Nine cheek pouch induced carcinomas were treated in the hamster group, with a mean volume decrease of 85.8% (from 44.8% to 100%) (initial mean volume = 210 mm³ vs. post PDT mean volume = 97 mm³). Histology analysis showed 4/9 complete responses.ConclusionIntratumoral MB appears efficient as PDT agent for cancer treatment in animal models. Further studies are needed to assess the safety and efficacy of MB-associated PDT for the treatment of lung cancer in humans.     

Photodynamic therapy using Photofrin and excimer dye laser treatment for superficial oral squamous cell carcinomas with long-term follow up

ObjectivesPhotodynamic therapy (PDT) is a very effective treatment for superficial malignancies that does not result in loss of normal tissue. Here, we report successful PDT treatment of superficial oral cancers and its clinical outcome with long-term follow up.Materials and methodsThirty-four superficial oral squamous cell carcinomas were treated with PDT, and the effects were evaluated. Each patient received Photofrin (2 mg/kg) intravenously 48 h prior to light irradiation. Photoradiation was performed at doses of 100–150 J/cm² using a 630-nm wavelength excimer dye laser.ResultsSix months after PDT, 30 patients (88.2%) showed complete responses while 9 patients (26.5%) had local relapses during long-term follow-up. The 5-year overall survival, disease-specific survival, and disease-free survival rates were 76.5%, 84.6%, and 63.3%, respectively. Lesions with red patches had a significantly higher recurrence rate than lesions with white patches. Accurate evaluation of the extent of lesions and appropriate photoradiation were important in improving outcomes. Adverse events observed included sunburn and sequestrum formation of alveolar bone. No abnormal laboratory values or systemic complications were observed.ConclusionPDT using Photofrin as the photosensitizer is an effective treatment modality for superficial oral carcinomas, with excellent healing and minimal side effects.     

Synthesis and characterization of photosensitive gelatin-based hydrogels for photodynamic therapy in HeLa-CCL2 cell line

BackgroundHydrogel systems are increasingly gaining visibility involving biomedicine, tissue engineering, environmental treatments, and drug delivery systems. These systems have a three-dimensional network composition and high-water absorption capacity, are biocompatible, allowing them to become an option as photosensitizer carriers (PS) for applications in Photodynamic Therapy (PDT) protocols.MethodsA nanohydrogel system (NAHI), encapsulated with chloroaluminium phthalocyanine (ClAlPc) was synthesized for drug delivery.. NAHI was synthesized using gelatin as based polymer by the chemical cross-linking technique. The drug was encapsulated by immersing the hydrogel in a 1.0 mg.mL⁻¹ ClAlPc solution. The external morphology of NAHI was examined by scanning electron microscopy (SEM). The degree of swelling of the synthesized system was evaluated to determine the water absorption potential. The produced nanohydrogel system was characterized by photochemical, photophysical and photobiologial studies.ResultsThe images from the SEM analysis showed the presence of three-dimensional networks in the formulation. The swelling test demonstrated that the nanohydrogel freeze-drying process increases its water holding capacity. All spectroscopic results showed excellent photophysical parameters of the drug studied when served in the NAHI system. The incorporation efficiency was 70%. The results of trypan blue exclusion test have shown significant reduction (p < 0.05) in the cell viability for all groups treated with PDT, in all concentrations tested. In HeLa cells, PDT mediated by 0,5 mg.mL⁻¹ ClAlPc encapsulated in NAHI showed a decrease in survival close to 95%. In the internalization cell study was possible to observe the internalization of phthalocyanine after one hour of incubation, at 37 °C, with the the accumulation of PS in the cytoplasm and inside the nucleus at both concentrations tested.ConclusionsGiven the peculiar performance of the selected system, the resulting nanohydrogel is a versatile platform and display potential applications as controlled delivery systems of photosensitizer for photodynamic therapy application.     

In vitro effects of photodynamic therapy induced by chloroaluminum phthalocyanine nanoemulsion

BackgroundThe photodynamic therapy (PDT) has been used to treat cancer mainly by inducing oxidative stress. Our aim was to evaluate the effect of PDT and its combination with methoxyamine (MX), a blocker of base excision repair (BER), in cells expressing high levels of the APE1 protein, which is involved in cell oxidative damage response.MethodsThe HeLa and A549 cells were treated for 3 h with chloroaluminum phthalocyanine incorporated into a well-designed nanoemulsion (ClAlPc/NE); and then irradiated by visible light (@670 nm) with doses of 0.1, 0.5 and 1.0 J/cm². A simultaneous combination of MX + ClAlPc/NE was performed and then irradiated with the selected dose of 0.5 J/cm². The treatments were evaluated in terms of viability, clonogenicity, DNA fragmentation, and cell death mechanism by apoptosis and/or necrosis.ResultsThe APE1 protein expression observed was higher in HeLa than in A549. Both cell lines exhibited substantial differences in cell cytotoxicity. The PDT decreased the clonogenicity of HeLa by inducing apoptosis (sub-G1 and annexin detection). Additionaly, the MX potentiates the PDT-effects in HeLa. Otherwise, low cytotoxicity was observed in A549 cells.ConclusionThe PDT induced apoptosis in high APE1 expressive HeLa cells, and the blockage of BER by MX increased its effects.     

Photodynamic therapy during second surgery for recurrent gliomas improves survival

BackgroundGlioma accounts for most central nervous system tumors, and the degree of invasion and malignancy are higher in the recurrent glioma. Photodynamic therapy (PDT) is an effective strategy in glioma. This study aimed to explore the risk factors for re-recurrence after a second glioma surgery and the effects of PDT on re-recurrence.MethodsThis was a retrospective study in the Second Affiliated Hospital of Harbin Medical University in China, and 43 patients that received the secondary surgery for recurrent glioma were included. The Kaplan-Meier test and Cox proportional hazard method were used to analyze.ResultsThe total re-recurrence rate after the second surgery for recurrent glioma was 48.84%. When the age increased by 1, the risk of re-recurrence increased 1.065 times (95% CI 1.000–1.134, P = 0.049). High matrix metalloproteinase (MMP) 2 expression was associated with a significantly higher risk of re-recurrence than low MMP2 expression (HR = 25.550, 95% CI 3.190–204.650, P = 0.002). Pathological grades IV and III were associated with a significantly higher risk of re-recurrence than pathological grade II (HR = 17.121, 95% CI 2.345–124.986, P = 0.005; HR = 2863.470, 95% CI 100.697–81,427.197, P < 0.001). PDT decreased the risk of re-recurrence (HR = 25.550, 95% CI 3.190–204.650, P = 0.002) and increased survival time (HR = 3.611, 95% CI 1.012–12.888, P = 0.048).ConclusionThe age, MMP2 expression, and pathological grade are independent risk factors for re-recurrence after a second surgery for recurrent glioma. PDT during the second surgery decreased the risk of re-recurrence and increased survival time.