[No Title Available]

Sibata, Cláudio H.; Colussi, Valdir C.; Oleinick, Nancy L.; Kinsella, T.

doi:10.1590/s0100-879x2000000800002

Cited by 148 publications

(45 citation statements)

References 52 publications

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“…This is surprising because porphyrin-mediated photosensitization has typically been attributed to their large yield for triplet state-sensitized singlet oxygen ( 1 O 2 ) or the formation of other ROS 22. These mechanisms are also commonly accepted as the major, if not the exclusive, contributors to the biomedical applications of porphyrins 17. However, our results suggest a new possibility for the mechanisms triggered by porphyrins interacting with biomolecules: an O 2 -independent, Type III photosensitization.…”

Section: Discussionmentioning

confidence: 77%

Photoinduced Unfolding of β-Lactoglobulin Mediated by a Water-Soluble Porphyrin

et al. 2009

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We investigated the effects that the irradiation of a tetra-anionic porphyrin (meso-tetrakis (sulfonatophenyl) porphyrin) non-covalently bound to β-lactoglobulin (BLG), produce on the conformation of the protein. Although BLG is not a potential target for the biomedical applications of porphyrins, it is a useful model for investigating the effects of photoactive ligands on small globular proteins. We show in this manuscript that irradiation causes a large unfolding of the protein and that the conformational change is not mediated by the formation of reactive oxygen species. Instead our data are consistent with an electron transfer mechanism that is capable of triggering structural changes in the protein and causes the Trp19 residue to undergo chemical modifications to form a derivative of kynurenine. This demonstrates that protein unfolding is prompted by a Type-III photosensitizing mechanisms. Type-III mechanisms have been suggested previously, but they have been largely neglected as useful mediators of biomolecular damage. Our study demonstrates that porphyrins can be used as mediators of localized protein conformational changes and that the biomedical applications as well as the mechanistic details of electron transfer between exogenous ligands and proteins merit further investigation.

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Section: Discussionmentioning

confidence: 77%

Photoinduced Unfolding of β-Lactoglobulin Mediated by a Water-Soluble Porphyrin

et al. 2009

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“…Over the last few decades, photosensitizer (PS)-mediated photodynamic therapy (PDT) has been introduced as a possible alternative non-invasive localized therapeutic modality for treating cancer as well as cardiovascular, ophthalmic, dermatological, and dental diseases [1,2,3,4,5,6,7]. PDT is a two-step procedure that involves the administration of a photosensitizing agent [8], followed by activation of the drug with non-thermal light of a specific wavelength [9].…”

Section: Introductionmentioning

confidence: 99%

Optimized Photodynamic Therapy with Multifunctional Cobalt Magnetic Nanoparticles

et al. 2017

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Photodynamic therapy (PDT) has been adopted as a minimally invasive approach for the localized treatment of superficial tumors, representing an improvement in the care of cancer patients. To improve the efficacy of PDT, it is important to first select an optimized nanocarrier and determine the influence of light parameters on the photosensitizing agent. In particular, much more knowledge concerning the importance of fluence and exposure time is required to gain a better understanding of the photodynamic efficacy. In the present study, we synthesized novel folic acid-(FA) and hematoporphyrin (HP)-conjugated multifunctional magnetic nanoparticles (CoFe2O4-HPs-FAs), which were characterized as effective anticancer reagents for PDT, and evaluated the influence of incubation time and light exposure time on the photodynamic anticancer activities of CoFe2O4-HPs-FAs in prostate cancer cells (PC-3 cells). The results indicated that the same fluence at different exposure times resulted in changes in the anticancer activities on PC-3 cells as well as in reactive oxygen species formation. In addition, an increase of the fluence showed an improvement for cell photo-inactivation. Therefore, we have established optimized conditions for new multifunctional magnetic nanoparticles with direct application for improving PDT for cancer patients.

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“…Among new therapies, photodynamic therapy (PDT) appears as a promising modality in cancer treatment with the lowest rates of side effects. Since the 1990s PDT has been investigated in basic research and showed to be more effective when nanostructured materials are used as the drug delivery system (DDS) for the active compounds [1-7]. Nowadays, interest in using PDT is increasing as a result of its recognition by the FDA (U.S. Food and Drug Administration) and other world agencies as an effective therapy for the treatment of several diseases, including cancer [8].…”

Section: Introductionmentioning

confidence: 99%

“…PDT is currently being used in the clinical phase for treatment of several types of tumors [9,10] around the world [11-14]. However, this therapy is particularly effective in the treatment of easily accessible lesions, such as non-melanoma skin cancers and lesions with well-defined borders [2], although it has been used outside oncology applications, including ophthalmology, dermatology, cardiology, virus inactivation, and blood purification [1]. …”

Section: Introductionmentioning

confidence: 99%

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Antitumor activity of photodynamic therapy performed with nanospheres containing zinc-phthalocyanine

et al. 2013

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BackgroundThe increasing incidence of cancer and the search for more effective therapies with minimal collateral effects have prompted studies to find alternative new treatments. Among these, photodynamic therapy (PDT) has been proposed as a very promising new modality in cancer treatment with the lowest rates of side effects, revealing itself to be particularly successful when the photosensitizer is associated with nanoscaled carriers. This study aimed to design and develop a new formulation based on albumin nanospheres containing zinc-phthalocyanine tetrasulfonate (ZnPcS4-AN) for use in the PDT protocol and to investigate its antitumor activity in Swiss albino mice using the Ehrlich solid tumor as an experimental model for breast cancer.MethodsEhrlich tumor’s volume, histopathology and morphometry were used to assess the efficacy of intratumoral injection of ZnPcS4-AN in containing tumor aggressiveness and promoting its regression, while the toxicity of possible treatments was assessed by animal weight, morphological analysis of the liver and kidneys, hemogram, and serum levels of total bilirubin, direct bilirubin, indirect bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transferase (GGT), alkaline phosphatase, creatinine and urea. In order to evaluate the efficacy of PDT, groups of animals treated with intratumoral injection of doxorubicin (Dox) were also investigated.ResultsIntratumoral injection of ZnPcS4-AN was found to be efficient in mediating PDT to refrain tumor aggressiveness and to induce its regression. Although tumor volume reduction was not significant, PDT induced a remarkable increase in the necrosis area seen in the tumor’s central region, as in other experimental groups, including tumor and Dox treated groups, but also in the tumor’s peripheral region. Further, PDT showed minimal adverse effects. Indeed, the use of ZnPcS4-AN in mediating PDT revealed anti-neoplastic activity similar to that obtained while using intratumoral Dox therapy.ConclusionsPDT mediated by the new formulation ZnPcS4-AN enhanced the inhibition of tumor growth while producing practically no adverse effects and thus emerges as a very promising nanotechnology-based strategy for solid cancer treatment.

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[No Title Available]

Cited by 148 publications

References 52 publications

Photoinduced Unfolding of β-Lactoglobulin Mediated by a Water-Soluble Porphyrin

Photoinduced Unfolding of β-Lactoglobulin Mediated by a Water-Soluble Porphyrin

Optimized Photodynamic Therapy with Multifunctional Cobalt Magnetic Nanoparticles

Antitumor activity of photodynamic therapy performed with nanospheres containing zinc-phthalocyanine

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