Crosstalk between ROS-dependent apoptotic and autophagic signaling pathways in Zn(II) phthalocyanine photodynamic therapy of melanoma

Melanoma is the most aggressive type of skin cancer, highly resistant to conventional therapies. Photodynamic therapy (PDT) is a minimally invasive treatment modality that combines the use of a photosensitizer, visible light and molecular oxygen, leading to ROS generation in the specific site of irradiation. The cationic zinc(II) phthalocyanine Pc13 has shown to be a potent photosensitizer in different melanoma cell lines. In this study, we explored the intracellular signaling pathways triggered by Pc13 PDT and the role of these cascades in the phototoxic action of Pc13 in human melanoma A375 cells. ROS-dependent activation of MAPKs p38, ERK, JNK and PI3K-I/AKT was observed after treatment. Inhibition of p38 reduced Pc13 phototoxicity, whereas blockage of ERK did not affect this response. Conversely, JNK inhibition potentiated the effect of Pc13 PDT. Results obtained indicate that p38 is involved in the cleavage of PARP-1, an important mediator of apoptosis. On the other hand, Pc13 irradiation induced the activation of an autophagic program, as evidenced by enhanced levels of Beclin-1, LC3-II and GFP-LC3 punctate staining. We also demonstrated that this autophagic response is promoted by JNK and negatively regulated by PI3K-I/AKT pathway. The blockage of autophagy increased Pc13 phototoxicity and enhanced PARP-1 cleavage, revealing a protective role of this mechanism, which tends to prevent apoptotic cell death.Furthermore, reduced susceptibility to treatment and increased activation of autophagy were detected in A375 cells submitted to repeated cycles of Pc13 PDT, indicating that autophagy could represent a mechanism of resistance to PDT. The efficacy of Pc13 PDT and an improved phototoxic action in combination with chloroquine were also demonstrated in tumor spheroids. In conclusion, we showed the interplay between apoptotic and autophagic signaling pathways triggered by Pc13 PDT-induced oxidative stress. Thus, autophagy modulation represents a promising therapeutic strategy to potentiate the efficacy of PDT in melanoma.Fil: Valli, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Garcia Vior, María Cecilia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Roguin, Leonor Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Marino, Veronica Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentin

Zinc(II) phthalocyanines as photosensitizers for antitumor photodynamic therapy

Photodynamic therapy (PDT) is a highly specific and clinically approved method for cancer treatment in which a nontoxic drug known as photosensitizer (PS) is administered to a patient. After selective tumor irradiation, an almost complete eradication of the tumor can be reached as a consequence of reactive oxygen species (ROS) generation, which not only damage tumor cells, but also lead to tumor-associated vasculature occlusion and the induction of an immune response. Despite exhaustive investigation and encouraging results, zinc(II) phthalocyanines (ZnPcs) have not been approved as PSs for clinical use yet. This review presents an overview on the physicochemical properties of ZnPcs and biological results obtained both in vitro and in more complex models, such as 3D cell cultures, chicken chorioallantoic membranes and tumor-bearing mice. Cell death pathways induced after PDT treatment with ZnPcs are discussed in each case. Finally, combined therapeutic strategies including ZnPcs and the currently available clinical trials are mentioned.Fil: Roguin, Leonor Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Chiarante, Nicolás Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Garcia Vior, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Marino, Veronica Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Biológica; Argentin

Synergistic antitumor effect of a penicillin derivative combined with thapsigargin in melanoma cells

Purpose: To investigate the effect of TAP7f, a penicillin derivative previously characterized as a potent antitumor agent that promotes ER stress and apoptosis, in combination with thapsigargin, an ER stress inducer, on melanoma cells. Methods: The synergistic antiproliferative effect of TAP7f in combination with thapsigargin was studied in vitro in murine B16-F0 melanoma cells, and in human A375 and SB2 melanoma cells. In vivo assays were performed with C57BL/6J mice challenged with B16-F0 cells. Immunofluorescence and Western blot assays were carried out to characterize the induction of ER stress and apoptosis. Necrotic tumor areas and the potential toxicity of the combined therapy were examined by histological analysis of tissue sections after hematoxylin-eosin staining. Results: In vitro, the combination of TAP7f with thapsigargin synergistically inhibited the proliferation of murine B16-F0, and human A375 and SB2 melanoma cells. When non-inhibitory doses of each drug were simultaneously administered to C57BL/6J mice challenged with B16-F0 cells, a 50% reduction in tumor volumes was obtained in the combined group. An apoptotic response characterized by higher expression levels of Baxenhanced PARP-1 cleavage and the presence of active caspase 3 was observed in tumors from the combined treatment. In addition, higher expression levels of GADD153/CHOP and ATF4 were found in tumors of mice treated with both drugs with respect to each drug used alone, indicating the induction of an ER stress response. No signs of tissue toxicity were observed in histological sections of different organs extracted from mice receiving the combination. Conclusion: The synergistic and effective antitumor action of TAP7f in combination with thapsigargin could be considered as a potential therapeutic strategy for melanoma treatment.Fil: Bellizzi, Yanina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Cornier, Patricia Griselda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Delpiccolo, Carina Maria Lujan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Mata, Ernesto Gabino. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Blank, Viviana Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Roguin, Leonor Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentin

Lysosomal permeabilization and endoplasmic reticulum stress mediate the apoptotic response induced after photoactivation of a lipophilic zinc(II) phthalocyanine

We have previously reported that the phototoxic action of the lipophilic phthalocyanine Pc9 (2,9(10),16(17),23(24) tetrakis[(2-dimethylamino)ethylsulfanyl]phthalocyaninatozinc(II)) encapsulated into poloxamine micelles is related to the induction of an apoptotic response in murine colon CT26 carcinoma cells. In the present study, we explored the intracellular signals contributing to the resulting apoptotic death. We found that Pc9-T1107 arrests cell cycle progression immediately after irradiation promoting then an apoptotic response. Thus, 3 h after irradiation the percentage of hypodiploid cells increased from 5.9 ± 0.6% to 23.1 ± 0.1%; activation of caspases 8 and 9 was evident; the population of cells with loss of mitochondrial membrane potential increased from 1.1 ± 0.4% to 44.0 ± 9.3%; the full-length forms of Bid and PARP-1 were cleaved; and a 50% decrease of the expression levels of the anti-apoptotic proteins Bcl-2 and Bcl-X L was detected. We also found that the photosensitizer, mainly retained in lysosomes and endoplasmic reticulum (ER), promotes the permeabilization of lysosomal membranes and induces ER stress. Lysosomal membrane permeabilization was demonstrated by the reduction of acridine orange lysosome fluorescence, the release of Cathepsin D into the cytosol and ∼50% decrease of Hsp70, a chaperone recognized as a lysosomal stabilizer. Cathepsin D also contributed to Bid cleavage and caspase 8 activation. The oxidative damage to the ER induced an unfolded protein response characterized, 3 h after irradiation, by a 3-fold increase in cytosolic Ca 2+ levels and 3–4 times higher expression of ER chaperones GRP78/BIP, calnexin, Hsp90 and Hsp110. The cell death signaling promoted by cytosolic Ca 2+ , calpains and lysosomal proteases was partially abolished by the Ca 2+ chelator BAPTA-AM, the calpain inhibitor PD 150606 and proteases inhibitors. Furthermore, Bax down-regulation observed in Pc9-treated cells was undetectable in the presence of PD 150606, indicating that calpains contribute to Bax proteolytic damage. In summary, our results indicate that photoactivation of Pc9-T1107 led to lysosomal membrane permeabilization, induction of ER stress and activation of a caspase-dependent apoptotic cell death.Fil: Chiarante, Nicolás Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Garcia Vior, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Rey, Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; ArgentinaFil: Marino, Veronica Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Roguin, Leonor Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentin

Mechanism of action of a triazolyl peptidyl penicillin in melanoma cells and synergistic antitumor effect of its combination with thapsigargin

In a previous study, we demonstrated that TAP7f, a synthetic triazolylpeptidyl penicillin, induces an apoptotic response and behaves as an effective antitumor agent in murine melanoma cells. In this work, we comparatively examined its mechanism of action in murine B16-F0 and human A375 melanoma cells. We first studied the contribution of an endoplasmic reticulum (ER) stress response to the apoptotic effect induced by the derivative. To this end, the expression levels of different ER stress-related proteins were evaluated by Western blot assays in both melanoma cell lines. A significant increase in the amount of ATF4, GADD153/CHOP, calnexin and GRP78/BIP was observed after incubating B16-F0 cells for 3 h or 6 h with a 20 µM concentration of TAP7f. A similar effect was observed in A375 cells for some of these ER markers. It was also shown that TAP7f increased phosphorylation levels of p38, JNK and Akt in both melanoma cell lines. Based on the effectiveness of combined therapies for cancer treatment, we decided to investigate the in vitro antiproliferative effect of TAP7f with thapsigargin, a well-known ER stress activator. The simultaneous incubation of different concentrations of both compounds showed a higher inhibition of cell growth with respect to the effect of each individual agent both in B16-F0 and A375 melanoma cells. The quantitative analysis of dose-effect curves obtained by using the Compusyn software rendered combination indexes lower than 1 (0.48-0.62 for B16-F0 and 0,41-0.76 for A375), indicating synergism. In conclusion, we showed that induction of ER stress and activation of p38, JNK and PI3K-I/Akt pathways are involved in the antitumor effect induced by TAP7f in melanoma cells. The efficacy of the combination of TAP7f with thapsigargin suggested that this therapy could be considered an auspicious tool for melanoma treatment.Fil: Anselmi Relats, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Bellizzi, Yanina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Cornier, Patricia Griselda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Delpiccolo, Carina Maria Lujan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Mata, Ernesto Gabino. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Blank, Viviana Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Roguin, Leonor Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaLXVI Reunión anual de la Sociedad Argentina de Investigación Clínica; LXIX Reunión anual de la Sociedad Argentina de Inmunología; LIII Reunión Anual de la Asociación Argentina de Farmacología Experimental y XI Reunión Anual de la Asociación Argentina de NanomedicinasArgentinaSociedad Argentina de Investigación ClínicaSociedad Argentina de InmunologíaAsociación Argentina de Farmacología ExperimentalAsociación Argentina de Nanomedicina

Novel hydro- and lipo-philic selenium zinc(II) phthalocyanines: Synthesis, photophysical properties and photodynamic effects on CT26 colon carcinoma cells

The synthesis and photochemical properties of two novel selenium zinc(II) phthalocyanines, a lipid-soluble 2,9(10),16(17),23(24)-tetrakis [(2-dimethylamino)ethylselanyl]phthalocyaninato zinc(II) (4) and its water-soluble quaternized derivative 2,9(10),16(17),23(24)-tetrakis [(2- trimethylammonium)ethylselanyl]phthalocyaninato zinc(II) tetraiodide (5), were investigated. Maximum absorption values were 689 nm and 684 nm for 4 and 5 in DMF, respectively. In addition, phthalocyanines were revealed to be very efficient singlet oxygen generators with high values of ΦΔ 0.74 and 0.84 for 4 and 5 in DMF, and they were photostable over the irradiation times studied. The photodynamic effect were evaluated on CT26 colon carcinoma cells. After light exposure, 4 and 5 were found to be cytotoxic, and IC50 values were 0.5 ± 0.1 μM and 2.3 ± 0.6 μM, respectively. The production of a greater amount of reactive oxygen species after phthalocyanines irradiation would be responsible for its potent phototoxic action on CT26 colon carcinoma cells.Fil: Ezquerra Riega, Sergio Dario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Orgánica; ArgentinaFil: Chiarante, Nicolás Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Valli, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Marino, Veronica Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Roguin, Leonor Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Awruch, Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Orgánica; ArgentinaFil: Garcia Vior, María Cecilia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Granulocyte colony-stimulating factor (G-CSF) upregulates β1 integrin and increases migration of human trophoblast Swan 71 cells via PI3K and MAPK activation

Multiple cytokines and growth factors expressed at the fetal-maternal interface are involved in the regulation of trophoblast functions and placental growth, but the role of G-CSF has not been completely established. Based on our previous study showing that G-CSF increases the activity of matrix metalloproteinase-2 and the release of vascular endothelial growth factor in Swan 71 human trophoblast cells, in this work we explore the possible contribution of G-CSF to cell migration and the G-CSF-triggered signaling pathway. We found that G-CSF induced morphological changes on actin cytoskeleton consistent with a migratory cell phenotype. G-CSF also up-regulated the expression levels of β1 integrin and promoted Swan 71 cell migration. By using selective pharmacological inhibitors and dominant negative mutants we showed that PI3K, Erk 1/2 and p38 pathways are required for promoting Swan 71 cell motility. It was also demonstrated that PI3K behaved as an upstream regulator of Erk 1/2 and p38 MAPK. In addition, the increase of β1 integrin expression was dependent on PI3K activation. In conclusion, our results indicate that G-CSF stimulates β1 integrin expression and Swan 71 cell migration by activating PI3K and MAPK signaling pathways, suggesting that G-CSF should be considered as an additional regulatory factor that contributes to a successful embryo implantation and to the placenta development.Fil: Furmento, Verónica Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; ArgentinaFil: Marino, Veronica Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; ArgentinaFil: Blank, Viviana Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; ArgentinaFil: Cayrol, Maria Florencia. Pontificia Universidad Católica Argentina ; ArgentinaFil: Cremaschi, Graciela Alicia. Pontificia Universidad Católica Argentina ; ArgentinaFil: Aguilar, Ruben Claudio. Purdue University; Estados UnidosFil: Roguin, Leonor Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentin

STAT1, STAT3 and p38MAPK are involved in the apoptotic effect induced by a chimeric cyclic interferon-α2b peptide

In the search of mimetic peptides of the interferon-α2b molecule (IFN-α2b), we have previously designed and synthesized a chimeric cyclic peptide of the IFN-α2b that inhibits WISH cell proliferation by inducing an apoptotic response. Here, we first studied the ability of this peptide to activate intracellular signaling pathways and then evaluated the participation of some signals in the induction of apoptosis. Stimulation of WISH cells with the cyclic peptide showed tyrosine phosphorylation of Jak1 and Tyk2 kinases, tyrosine and serine phosphorylation of STAT1 and STAT3 transcription factors and activation of p38 MAPK pathway, although phosphorylation levels or kinetics were in some conditions different to those obtained under IFN-α2b stimulus. JNK and p44/42 pathways were not activated by the peptide in WISH cells. We also showed that STAT1 and STAT3 downregulation by RNA interference decreased the antiproliferative activity and the amount of apoptotic cells induced by the peptide. Pharmacological inhibition of p38 MAPK also reduced the peptide growth inhibitory activity and the apoptotic effect. Thus, we demonstrated that the cyclic peptide regulates WISH cell proliferation through the activation of Jak/STAT signaling pathway. In addition, our results indicate that p38 MAPK may also be involved in cell growth regulation. This study suggests that STAT1, STAT3 and p38 MAPK would be mediating the antitumor and apoptotic response triggered by the cyclic peptide in WISH cells.Fil: Blank, Viviana Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Peña, Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Roguin, Leonor Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentin

Un nuevo rol para un conocido factor hematopoyético. Mecanismo de acción del G-CSF en células trofoblásticas humanas

El factor estimulante de colonias de granulocitos (G-CSF) esuna citoquina hematopoyética ampliamente conocida por sus efectos biológicos encélulas granulocíticas. En la clínica, esta proteína es comúnmente utilizadapara el tratamiento de neutropenias. A pesar de sus accionestejido-específicas, los recpetores para G-CSF (G-CSFR) han sido detectados endiferentes tejidos y tipos celulares. En el caso particular de la placenta, lapresencia de G-CSF y su receptor, así como la efectividad del tratamiento enmujeres con abortos recurrentes, sugirieron un posible rol funcional para esta citoquinas.En este trabajo, por primera vez, se describen las acciones biológicasdesencadenadas por la interacción de G-CSF:G-CSFR en una línea de célulastrofoblásticas humanas y se investigan las señales intracelulares que medianesas funciones. Nuestros resultados indican que el G-CSF contribuye, junto conotras hormonas y citoquinas, al desarrollo de la placenta, y abren una nueva perspectivapara el tratamiento de algunas patologías gestacionales que actualmente carecende tratamiento.Fil: Furmento, Verónica Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Marino, Veronica Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Roguin, Leonor Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentin

Oxidative stress generated by irradiation of a zinc(II) phthalocyanine induces a dual apoptotic and necrotic response in melanoma cells

Melanoma is an aggressive form of skin carcinoma, highly resistant to traditional therapies. Photodynamic therapy (PDT) is a non-invasive therapeutic procedure that can exert a selective cytotoxic activity toward malignant cells. In this work we evaluated the effect of a cationic zinc(II) phthalocyanine (Pc13) as photosensitizer on a panel of melanoma cells. Incubation with Pc13 and irradiation induced a concentration and light dose-dependent phototoxicity. In order to study the mechanism underlying Pc13-related cell death and to compare the effect of different doses of PDT, the most sensitive melanoma B16F0 cells were employed. By confocal imaging we showed that Pc13 targeted lysosomes and mitochondria. After irradiation, a marked increase in intracellular reactive oxygen species was observed and a complete protection from Pc13 phototoxicity was reached in the presence of the antioxidant trolox. Acridine orange/ethidium bromide staining showed morphological changes indicative of both apoptosis and necrosis. Biochemical hallmarks of apoptosis, including a significant decrease in the expression levels of Bcl-2, Bcl-xL and Bid and mitochondrial membrane permeabilization, were observed at short times post irradiation. The consequent release of cytochrome c to cytosol and caspase-3 activation led to PARP-1 cleavage and DNA fragmentation. Simultaneously, a dose dependent increase of lactate dehydrogenase in the extracellular compartment of treated cells revealed plasma membrane damage characteristic of necrosis. Taken together, these results indicate that a dual apoptotic and necrotic response is triggered by Pc13 PDT-induced oxidative stress, suggesting that combined mechanisms of cell death could result in a potent alternative for melanoma treatment.Fil: Valli, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Garcia Vior, María Cecilia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Roguin, Leonor Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Marino, Veronica Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentin