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The understanding of cancer immunity and antitumor factors generated by natural polysaccharides is not yet fully comprehended. Polysaccharides, like cashew gum (CG), can exhibit immunomodulatory action and may assist in the antitumor process and side effects relieve. This study aimed to determine the antitumor effect of CG alone or in combination with cyclophosphamide (CTX), and its interactions with immune cells, in a murine melanoma model, using the B16-F10 cell line. Tumor growth inhibition, hematological, histopathological, ELISA, flow cytometry, immunofluorescence, and qRT-PCR analyses were performed to elucidate the antitumor potential, involvement of immune cells, and potential toxic effects. CG showed significant tumor growth inhibition, reaching up to 42.9 % alone and 51.4 % in combination with CTX, with mild toxicity to organs. CG enhanced leukocyte count, even in the presence of CTX. Furthermore, CG influenced the activation of tumor-associated macrophages (TAM), characterized by an increase in Il4, as well as a reduction in Ifng, Il1b, Tgfb, and Il6 gene expression. Nevertheless, these effects did not compromise the antitumor activity of CG. In summary, the combination of CG with CTX is a promising approach for leukopenia, one of the most important side effects of cancer treatment and deserves further investigation.

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Purpose: Some first-line cytotoxic chemotherapics, e.g. doxorubicin, paclitaxel and oxaliplatin, induce activation of the immune system through immunogenic cell death (ICD). Tumor cells undergoing ICD function as a vaccine, releasing damage-associated molecular patterns (DAMPs), which act as adjuvants, and neoantigens of the tumor are recognized as antigens. ICD induction is rare, however it yields better and long-lasting antitumor responses to chemotherapy. Advanced metastatic melanoma (AMM) is incurable for more than half of patients. The discovery of ICD inducers against AMM is an interesting drug discovery strategy with high translational potential. Here we evaluated ICD induction of four highly cytotoxic chromomycins A (CA5-8). Methods: ICD features and DAMPs were evaluated using several in vitro techniques with metastatic melanoma cell line (B16-F10) exposed to chromomcins A5-8 such as flow cytometry, western blot, RT-PCR and luminescence. Additionally in vivo vaccination assays with CA5-treated cells in a syngeneic murine model (C57Bl/6) were performed to confirm ICD evaluating the immune cells activation and their antitumor activity. Results: B16-F10 treated with CA5-8 and doxorubicin exhibited ICD features such as autophagy and apoptosis, externalization of calreticulin, and releasing of HMGB1. However, CA5-treated cells had the best profile, also inducing ATP release, ERp57 externalization, phosphorylation of eIF2α and altering expression of transcription of genes related to autophagy, endoplasmic reticulum stress, and apoptosis. Bona fide ICD induction by CA5 was confirmed by vaccination of C57BL/6 mice with CA5-treated cells which activated antigen-presenting cells and T lymphocytes and stimulated antitumor activity. Conclusion: CA5 induces bona fide immunogenic cell death on melanoma.

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The chronification of ulcers or sores may result in a dramatic outcome such as amputation. Currently, the search for plant based treatments of various diseases/disorders, including complicated ones, is getting the attention of researchers worldwide. The soluble latex protein fraction (CpLP) obtained from Calotropis procera (Apocynaceae) was previously demonstrated to accelerate wound healing by topical application or when incorporated in a polyvinyl alcohol biomembrane (BioMemCpLP). Here, in vitro assays were performed to investigate and characterize the biocompatibility and bioactivity of latex proteins dressing. Macrophages (RAW 264.7), fibroblasts (L929) and keratinocytes (HaCaT) cell lines were used to evaluate the effect of CpLP. These cell lines were exposed to concentrations of CpLP comparable to those found in BioMemCpLP during 24-72 h. The cytotoxicity, proliferation, release of wound healing mediators (TGF-ß, VEGF, IL-10, IL-6, IL-1ß, TNF-α and NO) and migration of cells (E-cadherin and ß-catenin) incubated with CpLP was assessed and the cell adhesion to BioMemCpLP as well. The results showed that CpLP has no cytotoxic effects. It induced a suitable balance between pro- and anti-inflammatory mediators, enhanced proliferation and re-epithelialization in all cell lines, but the intensity of each effect was different at various doses in all cell strains. The BioMemCpLP stimulated cell adhesion to PVA substrate. The CpLP-PVA based biomembrane can be a good option for healing of different wounds.

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Saline environments are extreme habitats with a high diversity of microorganisms source of a myriad of biomolecules. These microorganisms are assigned as extremophiles recognized to be producers of new natural compounds, which can be synthesized by helping to survive under harshness and extreme conditions. In Brazil, in the saline and semi-arid region of Areia Branca (Caatinga biome), halotolerant bacteria (able to growth at high NaCl concentrations) were isolated from rhizosphere of native plants Blutaparon portulacoides and Spergularia sp. and their biopolymer production was studied. A total of 25 bacterial isolates were identified at genus level based on 16S rRNA gene sequence analysis. Isolates were mainly Gram-positive bacteria from Bacillaceae, Staphylococcaceae, Microbacteriaceae, and Bacillales XII incertae sedis families, affiliates to Bacillus, Staphylococcus, Curtobacterium, and Exiguobacterium genera, respectively. One of the Gram-negative isolates was identified as member of the Pseudomonadaceae family, genus Pseudomonas. All the identified strains were halotolerant bacteria with optimum growth at 0.6-2.0 M salt concentrations. Assays for biopolymer production showed that the halotolerant strains are a rich source of compounds as polyhydroxyalkanoates (PHA), biodegradable biopolymer, such as poly(3-hydroxybutyrate) (PHB) produced from low-cost substrates, and exopolysaccharides (EPS), such as hyaluronic acid (HA), metabolite of great interest to the cosmetic and pharmaceutical industry. Also, eight bacterial EPS extracts showed immunostimulatory activity, promising results that can be used in biomedical applications. Overall, our findings demonstrate that these biomolecules can be produced in culture medium with 0.6-2.0 M NaCl concentrations, relevant feature to avoid costly production processes. This is the first report of biopolymer-producing bacteria from a saline region of Caatinga biome that showed important biological activities.

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PURPOSE: Anticancer-drug efficacy seems to involve the direct interaction with host immune cells. Although topoisomerase I (Top I) inhibitors have been suggested to block LPS-evoked inflammation, the interaction between these drugs and toll-like receptor 4 (TLR4) is unaddressed. METHODS: SN-38, the active metabolite of the Top I inhibitor irinotecan, and TLR4 interaction was assessed using the in vitro luciferase nuclear factor-κB reporter assay, neutrophil migration to murine air-pouch, in silico simulation, and the thermal shift assay (TSA). Topotecan was used as a positive anti-inflammatory control. RESULTS: Non-cytotoxic concentrations of SN-38 attenuated LPS (a TLR4 agonist)-driven cell activation without affecting peptidoglycan (a TLR2 agonist)-activating response. Similarly, topotecan also prevented LPS-induced inflammation. Conversely, increasing concentrations of LPS reversed the SN-38 inhibitory effect. In addition, SN-38 abrogated LPS-dependent neutrophil migration and reduced TNF-α, IL-6, and keratinocyte chemoattractant levels in the air-pouch model, but failed to inhibit zymosan (a TLR2 agonist)-induced cell migration. A two-step molecular docking analysis indicated two potential binding sites for the SN-38 in the MD-2/TLR4 complex, the hydrophobic MD-2 pocket (binding energy of - 8.1 kcal/mol) and the rim of the same molecule (- 6.9 kcal/mol). The topotecan also bound to the MD-2 pocket. In addition, not only the lactone forms, but also the carboxylate conformations of both Top I inhibitors interacted with the MD-2 molecule. Furthermore, the TSA suggested the interaction of SN-38 with MD-2. CONCLUSIONS: Therefore, SN-38 inhibits acute inflammation by blocking LPS-driven TLR4 signaling. This mechanism seems to be shared by other Top I inhibitors.

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This review will discuss the contributions of marine natural molecules, a source only recently found to have pharmaceutical prospects, to the development of anticancer drugs. Of the seven clinically utilized compounds with a marine origin, four are used for the treatment of cancer. The development of these drugs has afforded valuable knowledge and crucial insights to meet the most common challenges in this endeavor, such as toxicity and supply. In this context, the development of these compounds will be discussed herein to illustrate, with successful examples provided by cytarabine, trabectedin, eribulin and brentuximab vedotin, the steps involved in this process as well as the scientific advances and technological innovation potential associated with developing a new drug from marine resources.

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This review will discuss the contributions of marine natural molecules, a source only recently found to have pharmaceutical prospects, to the development of anticancer drugs. Of the seven clinically utilized compounds with a marine origin, four are used for the treatment of cancer. The development of these drugs has afforded valuable knowledge and crucial insights to meet the most common challenges in this endeavor, such as toxicity and supply. In this context, the development of these compounds will be discussed herein to illustrate, with successful examples provided by cytarabine, trabectedin, eribulin and brentuximab vedotin, the steps involved in this process as well as the scientific advances and technological innovation potential associated with developing a new drug from marine resources.

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Las serpientes del género Crotalus ganaron espacio significativo en el campo científico desde el desarrollo de investigaciones con su veneno que involucran la actividad citotóxica. Crotalus durissus cascavella es la única subespecie grabadas del bioma de la Caatinga del nordeste de Brasil y los estudios carecen en sus propiedades del veneno. El presente estudio evaluó el veneno crudo de C. d. cascavella por su actividad citotóxica in vitro contra líneas celulares tumorales y las células normales. El mecanismo de la muerte celular inducida por este veneno también se investigó. C. d. cascavella mostró una alta citotoxicidad (valores de IC50 que oscila desde 2,7 hasta 6,9 g/mL) contra cinco líneas de células tumorales, entre las cuales: OVCAR - 8 y SKOV3 (carcinoma de ovario), PC-3M (carcinoma metastásico de próstata), MCF-7 (carcinoma de mama), SF - 268 (glioblastoma) y PBMC también. Las células tratadas con C. d. cascavella disparó la cascada apoptótica, según lo confirmado por diversos métodos que se muestran en este trabajo. Estos resultados refuerzan así el potencial biomédico y farmacológico de las toxinas del veneno de esta especie.

Snakes from the genus Crotalus gained significant space in the scientific field since the development of researches with their venom involving cytotoxic activity. Crotalus durissus cascavella is the only subspecies recorded of the Caatinga biome of Northeastern Brazil and its noticed a lack of studies on its venom properties. The present study evaluated the crude venom of C. d. cascavella for its cytotoxic activity in vitro against both tumor cell lines and normal cells. The mechanism of cell death induced by this venom was also investigated. C. d. cascavella venom presented high cytotoxicity (IC50 values ranging from 2.7 to 6.9 µg/mL) against five tumor cells lines: OVCAR-8 and SKOV3 (ovarian carcinomas), PC-3M (metastatic prostate carcinoma), MCF-7 (breast carcinoma), and SF-268 (glioblastoma) and PBMC as well. The cells treated with C. d. cascavella venom triggered the apoptotic pathway as confirmed by several methods. These results underline the biomedical potential of toxins from the venom from this species.

Serpentes do Gênero Crotalus ganhou espaço significativo no campo científico, desde o desenvolvimento de pesquisas com seu veneno envolvendo atividade citotóxica. A Crotalus durissus cascavella (C.d.cascavella) é uma subespécie característica da Caatinga do Nordeste do Brasil e faltam estudos sobre as propriedades de seu veneno. O presente estudo avaliou o veneno bruto de C. d. cascavella para a sua atividade citotóxica in vitro contra as linhagens de células tumorais e células normais. O mecanismo de morte celular induzida por este veneno também foi investigado. Observou-se alta citotoxicidade (valores de IC50 entre 2,7-6,9 µg/mL) contra cinco linhagens de células tumorais, dentre elas: OVCAR - 8 e SKOV3 (carcinoma ovariano), PC-3M (carcinoma metastático de próstata), MCF-7 (carcinoma mamário), SF - 268 (glioblastoma) e PBMC. As células tratadas dispararam a cascata apoptótica, como confirmado por vários métodos demonstrados neste trabalho. Esses resultados reforçam, assim, o potencial biomédico e farmacológico das toxinas do veneno dessa espécie.

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Las serpientes del género Crotalus ganaron espacio significativo en el campo científico desde el desarrollo de investigaciones con su veneno que involucran la actividad citotóxica. Crotalus durissus cascavella es la única subespecie grabadas del bioma de la Caatinga del nordeste de Brasil y los estudios carecen en sus propiedades del veneno. El presente estudio evaluó el veneno crudo de C. d. cascavella por su actividad citotóxica in vitro contra líneas celulares tumorales y las células normales. El mecanismo de la muerte celular inducida por este veneno también se investigó. C. d. cascavella mostró una alta citotoxicidad (valores de IC50 que oscila desde 2,7 hasta 6,9 g/mL) contra cinco líneas de células tumorales, entre las cuales: OVCAR - 8 y SKOV3 (carcinoma de ovario), PC-3M (carcinoma metastásico de próstata), MCF-7 (carcinoma de mama), SF - 268 (glioblastoma) y PBMC también. Las células tratadas con C. d. cascavella disparó la cascada apoptótica, según lo confirmado por diversos métodos que se muestran en este trabajo. Estos resultados refuerzan así el potencial biomédico y farmacológico de las toxinas del veneno de esta especie.(AU)

Snakes from the genus Crotalus gained significant space in the scientific field since the development of researches with their venom involving cytotoxic activity. Crotalus durissus cascavella is the only subspecies recorded of the Caatinga biome of Northeastern Brazil and its noticed a lack of studies on its venom properties. The present study evaluated the crude venom of C. d. cascavella for its cytotoxic activity in vitro against both tumor cell lines and normal cells. The mechanism of cell death induced by this venom was also investigated. C. d. cascavella venom presented high cytotoxicity (IC50 values ranging from 2.7 to 6.9 µg/mL) against five tumor cells lines: OVCAR-8 and SKOV3 (ovarian carcinomas), PC-3M (metastatic prostate carcinoma), MCF-7 (breast carcinoma), and SF-268 (glioblastoma) and PBMC as well. The cells treated with C. d. cascavella venom triggered the apoptotic pathway as confirmed by several methods. These results underline the biomedical potential of toxins from the venom from this species.(AU)

Serpentes do Gênero Crotalus ganhou espaço significativo no campo científico, desde o desenvolvimento de pesquisas com seu veneno envolvendo atividade citotóxica. A Crotalus durissus cascavella (C.d.cascavella) é uma subespécie característica da Caatinga do Nordeste do Brasil e faltam estudos sobre as propriedades de seu veneno. O presente estudo avaliou o veneno bruto de C. d. cascavella para a sua atividade citotóxica in vitro contra as linhagens de células tumorais e células normais. O mecanismo de morte celular induzida por este veneno também foi investigado. Observou-se alta citotoxicidade (valores de IC50 entre 2,7-6,9 µg/mL) contra cinco linhagens de células tumorais, dentre elas: OVCAR - 8 e SKOV3 (carcinoma ovariano), PC-3M (carcinoma metastático de próstata), MCF-7 (carcinoma mamário), SF - 268 (glioblastoma) e PBMC. As células tratadas dispararam a cascata apoptótica, como confirmado por vários métodos demonstrados neste trabalho. Esses resultados reforçam, assim, o potencial biomédico e farmacológico das toxinas do veneno dessa espécie.(AU)

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The present study highlights the biological effects of chromomycin A2 toward metastatic melanoma cells in culture. Besides chromomycin A2, chromomycin A3 and demethylchromomycin A2 were also identified from the extract derived from Streptomyces sp., recovered from Paracuru Beach, located in the northeast region of Brazil. The cytotoxic activity of chromomycin A2 was evaluated across a panel of human tumor cell lines, which found IC50 values in the nM-range for exposures of 48 and 72 h. MALME-3M, a metastatic melanoma cell line, showed the highest sensitivity to chromomycin A2 after 48h incubation, and was chosen as a model to investigate this potent cytotoxic effect. Treatment with chromomycin A2 at 30 nM reduced cell proliferation, but had no significant effect upon cell viability. Additionally, chromomycin A2 induced accumulation of cells in G0/G1 phase of the cell cycle, with consequent reduction of S and G2/M and unbalanced expression of cyclins. Chromomycin A2 treated cells depicted several cellular fragments resembling autophagosomes and increased expression of proteins LC3-A and LC3-B. Moreover, exposure to chromomycin A2 also induced the appearance of acidic vacuolar organelles in treated cells. These features combined are suggestive of the induction of autophagy promoted by chromomycin A2, a feature not previously described for chromomycins.

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