Lipophilicity of bacteriochlorin-based photosensitizers as a determinant for PDT optimization through the modulation of the inflammatory mediators

Photodynamic therapy (PDT) augments the host antitumor immune response, but the role of the PDT effect on the tumor microenvironment in dependence on the type of photosensitizer and/or therapeutic protocols has not been clearly elucidated. We employed three bacteriochlorins (F2BOH, F2BMet and Cl2BHep) of different polarity that absorb near-infrared light (NIR) and generated a large amount of reactive oxygen species (ROS) to compare the PDT efficacy after various drug-to-light intervals: 15 min. (V-PDT), 3h (E-PDT) and 72h (C-PDT). We also performed the analysis of the molecular mechanisms of PDT crucial for the generation of the long-lasting antitumor immune response. PDT-induced damage affected the integrity of the host tissue and developed acute (protocol-dependent) local inflammation, which in turn led to the infiltration of neutrophils and macrophages. In order to further confirm this hypothesis, a number of proteins in the plasma of PDT-treated mice were identified. Among a wide range of cytokines (IL-6, IL-10, IL-13, IL-15, TNF-α, GM-CSF), chemokines (KC, MCP-1, MIP1α, MIP1β, MIP2) and growth factors (VEGF) released after PDT, an important role was assigned to IL-6. PDT protocols optimized for studied bacteriochlorins led to a significant increase in the survival rate of BALB/c mice bearing CT26 tumors, but each photosensitizer (PS) was more or less potent, depending on the applied DLI (15 min, 3 h or 72 h). Hydrophilic (F2BOH) and amphiphilic (F2BMet) PSs were equally effective in V-PDT (>80 cure rate). F2BMet was the most efficient in E-PDT (DLI = 3h), leading to a cure of 65 % of the animals. Finally, the most powerful PS in the C-PDT (DLI = 72 h) regimen turned out to be the most hydrophobic compound (Cl2BHep), allowing 100 % of treated animals to be cured at a light dose of only 45 J/cm2

Stratum corneum permeabilization with photoacoustic waves generated by piezophotonic materials

AbstractPhotoacoustic (PA) waves generated by short laser pulses absorbed by piezophotonic materials are shown to permeabilize the stratum corneum to large molecules and proteins. Two minutes of such PA waves at a laser pulse frequency of 20Hz increase the transepidermal water loss (TEWL) of healthy human skin by a factor of 2.5, and the skin relaxes to normal two minutes later. The intraepidermal delivery of Green Fluorescence Protein (GFP) in minipigs with this method does not lead to observable adverse effects. The distinctive features of the piezophotonic materials are the high light-to-pressure conversion efficiency and the generation of PA waves with the duration of the laser pulses. Such features combine to yield broadband pressure waves with steep pressure gradients that are capable of permeabilizing the stratum corneum

Tritolylporphyrin dimer as a new potent hydrophobic sensitizer for photodynamic therapy of melanoma

We report the synthesis, photochemical and photophysical properties and preliminary studies on biological effect of a new tritolylporphyrin dimer (T-D). Absorption and emission properties of T-D suggest its possible use in photodynamic therapy. T-D is capable of singlet oxygen production with 0.8 quantum yield. It also has a high photostability. The photodynamic properties of the dimer were examined following the growth of SKMEL 188 (human melanoma) cells irradiated with red light (cut off vs. non-irradiated cells) for an 81 J/cm2 dose. Our results suggest that tritolylporphyrine dimer T-D may be an interesting hydrophobic sensitizer for photodynamic therapy

Study of chemical sympathectomy in endotoxin-induced lethality and fibrin deposition

Study of chemical sympathectomy in endotoxin-induced lethality and fibrin deposition. Shock and the generalized Shwartzman reaction are well known features of endotoxin which have been shown to involve the sympathetic nervous system. The mechanism of sympathetic nervous system involvement with endotoxin injection was studied in rabbits chemically sympathectomized with 6-hydroxydopamine. Endotoxin, in doses producing a spectrum of morbidity and mortality in normal rabbits, was administered i.v. to chemically sympathectomized, normal, and unilateral renal surgically sympathectomized animals. Chemical sympathectomy produced a significant depletion of tissue norepinephrine which, in endotoxin recipient animals, was associated with a significantly lower mortality rate and greatly decreased fibrin deposition in the lungs and kidneys, despite intravascular coagulation. Unilateral renal sympathectomy afforded protection to the ipsilateral kidney, but data on mortality and systemic fibrin deposition were similar to those reported for normal rabbits given endotoxin. Six-hydroxydopamine prevents significant tissue injury secondary to endotoxin in this experimental model. In addition, the data provide direct evidence that an intact reactive sympathetic nervous system is essential for development of lethal toxicity and generalized Shwartzman reaction due to endotoxin.Etude de la sympathectomie chimique de la lethalité et des dépôts de fibrine chez animaux qui ont reçu l'endotoxine. Le choc et le phénomène de Schwartzman généralisé sont des conséquences bien connues de l'endotoxine et il a été montré que ces réactions impliquent le systéme nerveux sympathique. Le mécanisme de la mise en jeu du système nerveux sympathique par l'injection d'endotoxine a été étudié chez des lapins ayant subi une sympathectomie chimique par la 6-hydroxydopamine. L'endotoxine, aux doses qui déterminent une morbidité et une mortalité chez les lapins normaux, a été administrée par voie intraveineuse à des animaux normaux, ayant subi une sympathectomie chimique ou ayant subi une sympathectomie rénale, chirurgicale et unilatérale. La sympathectomie chimique a produit une déplétion significative de norépinéphrine tissulaire qui, chez les animaux qui ont reçu l'endotoxine, a été associée à une diminution significative de la mortalité et une diminution importante des dépôts de fibrine dans les poumons et les reins malgré la coagulation intravasculaire. La sympathectomie unilatérale a protégé le rein ipsilatéral mais la mortalité et les dépôts systémiques de fibrine ont été semblables à ceux observés chez les lapins normaux qui ont reçu l'endotoxine. La 6-hydroxydopamine diminue de façon significative les altérations tissulaires secondaires à l'endotoxine dans ce modèle expérimental. De surcroît, ces observations apportent la preuve directe de ce qu'un système nerveux sympathique intact et réactif est essentiel pour l'apparition de la léthalité et du phénomène de Schwartzman généralisé consécutifs à l'endotoxine

Anticancer potential of Thevetia peruviana fruit methanolic extract

Abstract Background: Thevetia peruviana (Pers.) K. Schum or Cascabela peruviana (L.) Lippold (commonly known as ayoyote, codo de fraile, lucky nut, or yellow oleander), native to Mexico and Central America, is a medicinal plant used traditionally to cure diseases like ulcers, scabies, hemorrhoids and dissolve tumors. The purpose of this study was to evaluate the cytotoxic, antiproliferative and apoptotic activity of methanolic extract of T. peruviana fruits on human cancer cell lines. Methods: The cytotoxic activity of T. peruviana methanolic extract was carried out on human breast, colorectal, prostate and lung cancer cell lines and non-tumorigenic control cells (fibroblast and Vero), using the MTT assay. For proliferation and motility, clonogenic and wound-healing assays were performed. Morphological alterations were monitored by trypan blue exclusion, as well as DNA fragmentation and AO/EB double staining was performed to evaluate apoptosis. The extract was separated using flash chromatography, and the resulting fractions were evaluated on colorectal cancer cells for their cytotoxic activity. The active fractions were further analyzed through mass spectrometry. Results: The T. peruviana methanolic extract exhibited cytotoxic activity on four human cancer cell lines: prostate, breast, colorectal and lung, with values of IC50 1.91 ± 0.76, 5.78 ± 2.12, 6.30 ± 4.45 and 12.04 ± 3.43 μg/mL, respectively. The extract caused a significant reduction of cell motility and colony formation on all evaluated cancer cell lines. In addition, morphological examination displayed cell size reduction, membrane blebbing and detachment of cells, compared to non-treated cancer cell lines. The T. peruviana extract induced apoptotic cell death, which was confirmed by DNA fragmentation and AO/EB double staining. Fractions 4 and 5 showed the most effective cytotoxic activity and their MS analysis revealed the presence of the secondary metabolites: thevetiaflavone and cardiac glycosides. Conclusion: T. peruviana extract has potential as natural anti-cancer product with critical effects in the proliferation, motility, and adhesion of human breast and colorectal cancer cells, and apoptosis induction in human prostate and lung cancer cell lines, with minimal effects on non-tumorigenic cell lines. Keywords: Cytotoxic activity, Anti-proliferative activity, Motility, Apoptosis, Human cancer cells, Flavonoid, Cardiac glycoside

Intersecting-state model calculations on fast and ultrafast excited-state proton transfers in naphthols and substituted naphthols

The intersecting-state model (ISM) is applied to the calculation of absolute rate constants for proton-transfer reactions of naphthols and substituted naphthols in the first singlet state and for ground states. ISM incorporates quantum-mechanical tunnelling, zero-point energy corrections and an electrophilicity parameter to account for the lowering of the binding energy of transition states. Good agreement with experimental rates is observed over 12 orders of magnitude. The lower reactivity of the photoacids in alcohols when compared to the behaviour in water can be accounted for the differences in the potential energy curves of the OH bonds. Patterns of reactivity with respect to free-energy relations and kinetic isotope effects are also discussed.http://www.sciencedirect.com/science/article/B6TGY-475RGSM-1/1/9e04c4b3aa962e371b9e858fc1575f1

Design of Pluronic-based formulation for enhanced redaporfin-photodynamic therapy against pigmented melanoma

The therapeutic outcome of photodynamic therapy (PDT) with redaporfin (a fluorinated sulfonamide bacteriochlorin, F₂BMet or LUZ11) was improved using Pluronic-based (P123, F127) formulations. Neither redaporfin encapsulated in Pluronic nor micelles alone exhibited cytotoxicity in a broad concentration range. Comprehensive in vitro studies against B16F10 melanoma cells showed that redaporfin-P123 micelles enhanced cellular uptake and increased oxidative stress compared with redaporfin-F127 or photosensitizer alone after short incubation times. ROS-sensitive fluorescent probes showed that the increased oxidative stress is due, at least in part, to a more efficient formation of hydroxyl radicals, and causes strong light-dose dependent apoptosis and necrosis. Tissue distribution and pharmacokinetic studies in tumor-bearing mice show that the Pluronic P123 formulation of redaporfin increases its bioavailability as well as the tumor-to-muscle and tumor-to-skin ratios, in comparison with Cremophor EL and Pluronic F127 formulations. Redaporfin in P123 was most successful in the PDT of C57BL/6J mice bearing subcutaneously implanted B16F10 melanoma tumors. Vascular-targeted PDT combining 1.5 mg kg^–1 redaporfin in P123 with a light dose of 74 J cm^–2 led to 100% complete cures (i.e., no tumor regrowth over one year post-treatment). This remarkable result reveals that modification of redaporfin with Pluronic block copolymers overcomes the resistance of melanoma cells to PDT possibly via increased tumor selectivity and enhanced ROS generation