Photodynamic therapy combined to cisplatin potentiates cell death responses of cervical cancer cells.

BACKGROUND: Photodynamic therapy (PDT) has proven to be a promising alternative to current cancer treatments, especially if combined with conventional approaches. The technique is based on the administration of a non-toxic photosensitizing agent to the patient with subsequent localized exposure to a light source of a specific wavelength, resulting in a cytotoxic response to oxidative damage. The present study intended to evaluate in vitro the type of induced death and the genotoxic and mutagenic effects of PDT alone and associated with cisplatin. METHODS: We used the cell lines SiHa (ATCC® HTB35™), C-33 A (ATCC® HTB31™) and HaCaT cells, all available at Dr. Christiane Soares' Lab. Photosensitizers were Photogem (PGPDT) and methylene blue (MBPDT), alone or combined with cisplatin. Cell death was accessed through Hoechst and Propidium iodide staining and caspase-3 activity. Genotoxicity and mutagenicity were accessed via flow cytometry with anti-gama-H2AX and micronuclei assay, respectively. Data were analyzed by one-way ANOVA with Tukey's posthoc test. RESULTS: Both MBPDT and PGPDT induced caspase-independent death, but MBPDT induced the morphology of typical necrosis, while PGPDT induced morphological alterations most similar to apoptosis. Cisplatin predominantly induced apoptosis, and the combined therapy induced variable rates of apoptosis- or necrosis-like phenotypes according to the cell line, but the percentage of dead cells was always higher than with monotherapies. MBPDT, either as monotherapy or in combination with cisplatin, was the unique therapy to induce significant damage to DNA (double strand breaks) in the three cell lines evaluated. However, there was no mutagenic potential observed for the damage induced by MBPDT, since the few cells that survived the treatment have lost their clonogenic capacity. CONCLUSIONS: Our results elicit the potential of combined therapy in diminishing the toxicity of antineoplastic drugs. Ultimately, photodynamic therapy mediated by either methylene blue or Photogem as monotherapy or in combination with cisplatin has low mutagenic potential, which supports its safe use in clinical practice for the treatment of cervical cancer.

Photodynamic activity of Photogem® in Leishmania promastigotes and infected macrophages.

Objectives: This study aimed to evaluate the effect of photodynamic therapy (PDT) with Photogem® in promastigotes of Leishmania braziliensis and Leishmania major, and in infected macrophages. Materials & methods: The following parameters were analyzed: Photogem® internalization, mitochondrial activity, viability, tubulin marking and morphological alterations in promastigotes and viability in infected macrophages. Results: Photogem® accumulated in the cytosol and adhered to the flagellum. Changes were observed in the mitochondrial activity in groups maintained in the dark, with no viability alteration. After PDT, viability decreased up to 80%, and morphology was affected. Conclusion: The results point out that PDT with Photogem® can reduce parasite and macrophage viability.

Effect of vitamin A as a neoadjuvant agent in chemotherapy and photodynamic therapy of Rhabdomyosarcoma cells.

Combinational therapy is among the most used treatment modality's to increase cancer treatment efficacy. It may also reduce side effects, treatment time, and development of drug resistance. The effects of different analogues of vitamin A (VA) as neoadjuvant agent were observed in this study with chemotherapeutic drugs (doxorubicin and methotrexate) and photodynamic therapy (PDT) using 5-ALA and Photogem as photosensitizers in RD cells. The uptake time of photosensitizer was optimized by means of spectrophotometric measurements. Diode laser (λ = 635 nm ±â€¯1 nm) was used as an illumination source for PDT. Responses of administered drugs were assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. VA and its analogues exert prophylactic and therapeutic effects. Protective or antagonistic effects (CI > 1) were observed in each of the case. These results propose that the use of VA as a neoadjuvant agent in combinational therapeutic modalities may reduce the efficacy of cancer treatment protocols as well as the existing side effects. Thus, VA is not the successful drug for combinational therapies and under treatment cancer patients should try to avoid its use with oxidative stress induction therapies (e.g. PDT, Radiotherapy, chemotherapy).

Light-driven photosensitizer uptake increases Candida albicans photodynamic inactivation.

Photodynamic Inactivation (PDI) is based on the use of a photosensitizer (PS) and light that results mainly in the production of reactive oxygen species, aiming to produce microorganism cell death. PS incubation time and light dose are key protocol parameters that influence PDI response; the correct choice of them can increase the efficiency of inactivation. The results of this study show that a minor change in the PDI protocol, namely light-driven incubation leads to a higher photosensitizer and more uniform cell uptake inside the irradiated zone. Furthermore, as the uptake increases, the damage caused by PDI also increases. The proposed light-driven incubation prior to the inactivation illumination dose has advantages when compared to the traditional PDI treatments since it can be more selective and effective. Using a violet light as pre-illumination (light-driven incubation) source and a red-light system as PDI source, it was possible to demonstrate that when compared to the traditional protocol of dark incubation, the pre-illuminated cell culture showed an inactivation increase of 7 log units. These in vitro results performed in Candida albicans cells may result in the introduction of a new protocol for PDI.

Fast elimination of onychomycosis by hematoporphyrin derivative-photodynamic therapy.

Onychomycosis is a fungal nail disease and is one of the major onychopathy worldwide. Topical or oral antifungal therapies are used to treat this disease, but often they are inefficient and oral medications can even cause several side effects. Photodynamic therapy (PDT) is a well established technique and hence, may represent an alternative non invasive technique for the treatment of onychomycosis. In this work, we present a case of onychomycosis that was completely cured by using the porphyrin-photodynamic therapy. A 59-year-old patient, who had two nails with onychomycosis (the right and the left hallux, with more than thirty and ten years, respectively) caused by fungi was treated once a week for a period of six weeks. The nails were first treated and prepared by a specialist. An hour after the photosensitization, the nail was illuminated using a light source based on light emitting diodes (LEDs) in the red wavelength (630 nm, at a total dose of 54 J/cm(2)).

Photogem Induces Necrosis in Various Uterine Cervical Cancer Cell Lines by PDT.

PURPOSE: In order to elucidate the antitumor effect of photodynamic therapy (PDT), using a derivative of the photosensitizing agent hematoporphyrin (Photogem) and a diode laser, the cell death of uterine cancer cell lines (CaSki, HT3, HeLa, and SKOV-3), and mice transplanted with TC-1 lung cancer cells, were evaluated. MATERIALS AND METHODS: The morphological changes, MTT assay, flow cytometry, cytotoxicity and tumor growth inhibition study were evaluated at various time intervals after the PDT. RESULTS: The results showed that the survival rates of each cell line decreased with time and dose response after performing the PDT. Also, the PDT-induced damage of cancer cells was almost entirely confined to necrosis of the tumor cells in the early time courses. The irradiation of CaSki cells in the presence of Photogem induced plasma membrane disruption and cell shrinkage, indicating the plasma membrane as the main target for Photogem. In the in vivo experiment, significantly longer survival and a significantly smaller tumor size were seen over the time courses of the Photogem with irradiation compared to the untreated control groups; resorption of the tumor was also observed after the PDT treatment. CONCLUSION: Collectively, our results indicated that Photogem possesses anti-tumor effects, and necrosis-like death, with plasma membrane damage, was postulated to be the principal mechanism of the antitumor effect of the PDT using Photogem.