Highly effective decontamination in a hospital environment: An easy-to-operate, low-cost prototype.

Healthcare-associated infections (HAI) are illnesses acquired during healthcare and are often the most important adverse event during healthcare. With the aim of increasing the effectiveness of disinfection/decontamination processes in the health service with safe and not promote microbial resistance, we propose the development of portable equipment associated with type C ultraviolet light (UVC). The efficiency of the irradiance emitted by the equipment (at dosages 3.5, 5.0, and 60 mJ/cm2) was determined by the action exerted after exposure against four different bacterial (Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) and three different fungi (Candida albicans, C. parapsilosis, and Aspergillus section Fumigati). It was possible to observe that all treatments were capable of inactivating the bacterial species evaluated (p < 0.05), causing the irreversible death of these microorganisms. The most effective elimination of fungal agents was at a dose of 60 mJ/cm2 of UVC radiation, with a decrease in the fungal inoculum varying between 94% and 100% in relation to the control without exposure. Thus, our study showed that the application of the portable prototype with UVC light (254 nm) at a distance of 48 mm, allowed an average irradiance of 3.5 mW/cm2, with doses of 3.5 ≈ 60 mJ/cm2 (from 1 to 60 s of exposure), which can promote the total reduction of the bacteria evaluated and significantly reduce fungal growth. Therefore, this prototype could be used safely and effectively in the hospital environment, considerably reducing contamination and contributing to the reduction of healthcare-associated infection risk.

Bioactive C-phycocyanin exerts immunomodulatory and antitumor activity in mice with induced melanoma.

Melanoma is the most aggressive and deadly skin cancer. The difficulty in its treatment arises from its ability to suppress the immune system, making it crucial to find a substance that increases anti-tumor immunity. C-phycocyanin (C-PC) appears as a promising bioactive, with multifaceted effects against several cancers, but its efficacy against melanoma has only been tested in vitro. Therefore, we investigated C-PC's the anti-tumor and immunomodulatory action in a murine melanoma model. The tumor was subcutaneously induced in C57BL/6 mice by injecting B16F10 cells. The animals were injected subcutaneously with C-PC for three consecutive days. After euthanasia, the tumor was weighed and measured. The inguinal lymph node was removed, and the cells were stained with antibodies and analyzed by flow cytometry. The heart, brain and lung were analyzed by histopathology. C-PC increased the B cell population of the inguinal lymph node in percentage and absolute number. The absolute number of T lymphocytes and myeloid cells were also increased in the groups treated with C-PC. Thus, C-PC showed a positive immunomodulatory effect both animals with and without tumor. However, this effect was more pronounced in the presence of the tumor. Positive immune system modulation may be associated with a reduction in tumor growth in animals treated with C-PC. Administration of C-PC subcutaneously did not cause organ damage. Our findings demonstrate C-PC's immunomodulatory and anti-melanoma action, paving the way for clinical research with this bioactive.

Potential Therapeutic Targets of Quercetin in the Cutaneous Melanoma Model and Its Cellular Regulation Pathways: A Systematic Review.

Melanoma is a skin cancer with a high mortality rate due to its invasive characteristics. Currently, immunotherapy and targeted therapy increase patient survival but are ineffective in the advanced stages of the tumor. Quercetin (Que) is a natural compound that has demonstrated chemopreventive effects against different types of tumors. This review provides evidence for the therapeutic potential of Que in melanoma and identifies its main targets. The Scopus, Web of Science, and PubMed databases were searched, and studies that used free or encapsulated Que in melanoma models were included, excluding associations, analogs, and extracts. As a result, 73 articles were retrieved and their data extracted. Que has multiple cellular targets in melanoma models, and the main regulated pathways are cell death, redox metabolism, metastasis, and melanization. Que was also able to regulate important targets of signaling pathways, such as PKC, RIG-I, STAT, and P53. In murine models, treatment with Que reduced tumor growth and weight, and decreased metastatic nodules and angiogenic vasculature. Several studies have incorporated Que into carriers, demonstrating improved efficacy and delivery to tumors. Thus, Que is a promising therapeutic agent for the treatment of melanoma; however, further studies are needed to evaluate its effectiveness in clinical trials.

Effects of chemotherapeutic drugs on the antioxidant capacity of human erythroleukemia cells with MDR phenotype.

In this work, we identified that different chemotherapeutic drugs may select cells with different antioxidant capacities. For this, we evaluated the sensitivity of two multidrug-resistant (MDR) erythroleukemia cell lines: Lucena (resistant to vincristine, VCR) and FEPS (resistant to daunorubicin, DNR) derived from the same sensitive cell K562 (non-MDR) to hydrogen peroxide. In addition, we evaluated how the cell lines respond to the oxidizing agent in the absence of VCR/DNR. In absence of VCR, Lucena drastically decreases cell viability when exposed to hydrogen peroxide, while FEPS is not affected even without DNR. To analyze whether selection by different chemotherapeutic agents may generate altered energetic demands, we analyzed the production of reactive oxygen species (ROS) and the relative expression of the glucose transporter 1 gene (glut1). We observed that the selection through DNR apparently generates a higher energy demand than VCR. High levels of transcription factors genes expression (nrf2, hif-1α, and oct4) were kept even when the DNR is withdrawn from the FEPS culture for one month. Together, these results indicate that DNR selects cells with greater ability to express the major transcription factors related to the antioxidant defense system and the main extrusion pump (ABCB1) related to the MDR phenotype. Taking into account that the antioxidant capacity of tumor cells is closely related to resistance to multiple drugs, it is evident that endogenous antioxidant molecules may be targets for the development of new anticancer drugs.

Morita-Baylis-Hillman adduct 2-(3-hydroxy-2-oxoindolin-3-yl)acrylonitrile (ISACN) modulates the inflammatory process during LPS-induced acute lung injury.

BACKGROUND: Despite its homeostatic role, inflammation is involved in several pathologies, such as acute lung injury. Morita-Ballys-Hilman adducts (MBHA) are a group of synthetic molecules and present a wide range of biological activities, including anti-inflammatory action. Thus, this study aimed to assess whether ISACN, an MBHA, modulates inflammation during acute lung injury induced by lipopolysaccharide (LPS). METHODS: BALB/c mice were intraperitoneally treated with 24 mg/kg ISACN and challenged with LPS (2.5 mg/kg). On bronchoalveolar lavage fluid (BALF), we assessed the total and differential leukocyte count and measurement of protein leakage, cytokines (IL-1ß, IL-6, and TNF-α), and chemokine (CXCL-1). Additionally, lung histopathology was also performed (H&E staining). In vitro studies were conducted with peritoneal macrophages to assess the possible mechanism of action. They were cultured in the presence of ISACN (5 and 10 µM) and stimulated by LPS (1 µg/mL). RESULTS: ISACN reduced neutrophil migration, protein leakage, and inflammatory cytokines (IL-1ß, IL-6, and TNF-α) without interfering with the production of CXCL1. In addition, ISACN caused a decrease in LPS-induced lung injury as evident from histopathological changes. In peritoneal macrophages, ISACN diminishes the nitric oxide and cytokine levels (IL-1ß, IL-6, and TNF-α). The treatment with ISACN (10 µM) also reduced LPS-induced TLR4, CD69, iNOS overexpression, and the LPS-induced ERK, JNK, and p38 phosphorylation. CONCLUSION: Thus, this work showed for the first time the immunomodulatory action of MBHA in LPS-induced acute lung injury and provided new evidence for the mechanisms related to the anti-inflammatory effect of ISACN.

C-phycocyanin decreases proliferation and migration of melanoma cells: In silico and in vitro evidences.

The incidence and number of deaths caused by melanoma have been increasing in recent years, and the pigment C-phycocyanin (C-PC) appears as a possible alternative to treat this disease. So, the objective of this study was to combine in silico and in vitro analysis to understand the main anti-melanoma pathways exerted by C-PC. We evaluated the ability of C-PC to bind to the main cellular targets related in the progression of melanoma through molecular docking, and the reflection of this bind in the biological effects in the B16F10 cell line through in vitro analysis. Our results showed that C-PC was able to bind BRAF and MEK, which are related to the signal transduction pathway for proliferation and survival. There was also an interaction between C-PC and cyclin-dependent kinase 4 and 6. In vitro analysis demonstrated that C-PC decreased B16F10 cell proliferation, as observed by cell viability and mitotic index assays. C-PC also interacted with matrix metalloproteinase 2 and 9 and N-cadherin, which may have caused the decrease in cell migration observed in vitro. Besides that, C-PC interacts with VEGF, a factor responsible for regulating the proliferation and cellular invasion pathways. Finally, C-PC did not alter the cell viability of the non-tumoral melanocytes. Therefore, C-PC is a strong anti-tumor candidate for the treatment of melanoma, since it acts in different cellular pathways of melanoma, without causing damage to non-tumoral cells.

Patulin inhibits LPS-induced nitric oxide production by suppressing MAPKs signaling pathway.

Patulin (PAT) is a natural product isolated from several species of fungi. Here, we evaluated the effect of PAT (62.5-4,000 ng/ml) in lipopolysaccharide (LPS)-activated murine peritoneal macrophages. Cell viability assay showed that PAT at concentrations up to 250 ng/ml did not affect macrophage viability. PAT (250 ng/ml) significantly reduced LPS-induced nitric oxide production (by 98.4%), inducible nitric oxide synthase (iNOS) expression (by 83.5%), and iNOS messenger ribonucleic acid expression (by 100.0%). Moreover, PAT significantly reduced LPS-induced interleukin-1ß (by 80.6%), cluster of differentiation (CD) 69 (by 63.1%), and Toll-like receptor (TLR) 4 (by 91.9%) protein expression. Finally, PAT significantly reduced LPS-triggered phosphorylation of all mitogen-activated protein kinases (MAPK) assessed: extracellular signal-regulated kinase (ERK; by 89.5%), c-Jun N-terminal kinase (JNK; by 77.5%), and p38 (by 72.3%). Taken together, these data suggest that PAT downregulates acute inflammatory response, inhibiting nitric oxide production by suppressing CD69-TLR4/ERK-JNK-p38 MAPKs/Nos2/iNOS signaling pathway.

Relation between ABCB1 overexpression and COX2 and ALOX5 genes in human erythroleukemia cell lines.

This study aimed to characterize the relationship between the COX2 and ALOX5 genes, as well as their link with the multidrug resistance (MDR) phenotype in sensitive (K562) and MDR (K562-Lucena and FEPS) erythroleukemia cells. For this, the inhibitors of 5-LOX (zileuton) and COX-2 (acetylsalicylic acid-ASA) and cells with the silenced ABCB1 gene were used. The treatment with ASA caused an increase in the gene expression of COX2 and ABCB1 in both MDR cell lines, and a decrease in the expression of ALOX5 in the FEPS cells. Silencing the ABCB1 gene induced a decrease in COX2 expression and an increase in the ALOX5 gene. Treatment with zileuton did not alter the expression of COX2 and ABCB1. Cytometry data showed that there was an increase in ABCB1 protein expression after exposure to ASA. In addition, the increased activity of ABCB1 in the K562-Lucena cell line indicates that ASA may be a substrate for this efflux pump, corroborating the molecular docking that showed that ASA can bind to ABCB1. Regardless of the genetic alteration in COX2 and ABCB1, the direct relationship between these genes and the inverse relationship with ALOX5 remained in the MDR cell lines. We assume that ABCB1 can play a regulatory role in COX2 and ALOX5 during the transformation of the parental cell line K562, explaining the increased gene expression of COX2 and decreased ALOX5 in the MDR cell lines.

Synthesis of pyrazoline fatty chain derivatives and its effects on melanoma cells.

Skin cancer is the most common type of cancer in Brazil, representing 30% of all cases. Among these, melanoma represents only 3% of malignant neoplasms; however, it is the most serious and has a high capacity for metastasis. For this reason, it is extremely important to identify more efficient compounds and treatments that stop or decrease the proliferation of melanoma, even in its more advanced stages. This work reports the synthesis and biological evaluation of two homologous series of pyrazoline fatty chain derivatives as potent antitumoral agents in the melanoma B16F10 cell line. Cells were treated with pyrazoline fatty chain compounds (3, 30, 300, and 3000 µM) for 0, 24, 48, and 72 h. Decreased cell viability was observed when using most compounds at different concentrations and times. The structure-activity relationship (SAR) between antitumoral activity and the number of carbons and lipophilicity, as well as the oxygen-sulfur bioisosteric exchange, was evaluated. Among the tested derivatives, the lipophilic compounds 5-hydroxy-5-(trifluoromethyl)-3-undecyl-4,5-dihydro-1H-pyrazole-1-carboxamide (2d) and 5-hydroxy-5-(trifluoromethyl)-3-undecyl-4,5-dihydro-1H-pyrazole-1-thiocarboxamide (3d) showed the best results in the B16F10 cell line, as they produced the best cell viability decrease effects. The presence of fatty unbranched undecyl chain in the molecular structure appears to be important for its antimelanoma properties.

Anti-MDR Effects of Quercetin and its Nanoemulsion in Multidrug-Resistant Human Leukemia Cells.

BACKGROUND: Quercetin has potential against the Multidrug Resistance (MDR) phenotype, but with low bioavailability. The increase in the bioavailability can be obtained with nanostructures. OBJECTIVE: To analyze the effects of quercetin and its nanoemulsion on MDR and non-MDR cells. METHODS: We used high-pressure homogenization for nanoemulsion production; Trypan Blue for cytostatic/cytotoxicity assays; Epifluorescence microscope (with specific probes) for apoptosis and DNA damage; Real-Time PCR for gene expression; AutoDock Vina for docking and Flow Cytometry for efflux analysis. Quercetin exerted antiproliferative impact, induced apoptosis, necrosis and DNA damage on cells. RESULTS: Quercetin combined with vincristine showed an effect similar to verapamil (an ABCB1 inhibitor), and docking showed that it binds to ABCB1 in a similar region. Quercetin was also capable of altering ABCB1 gene expression. Quercetin in nanoemulsion maintained the cytotoxic and cytostatic effects of quercetin, which may increase bioavailability. Besides, the unloaded nanoemulsion was able to inhibit per se the efflux activity of ABCB1, demonstrating pharmacological action of this structure. CONCLUSION: Quercetin may be considered as a prospective drug to overcome resistance in cancer cells and its nanoemulsion can be an alternative for in vivo application.

Interaction Between Near-Infrared Radiation and Temozolomide in a Glioblastoma Multiform Cell Line: A Treatment Strategy?

Photodynamic therapy (PDT) is a potential therapeutic modality against cancer, resulting from the interaction of a photosensitizer (PS) and radiation that generates damage to tumor cells. The use of near-infrared radiation (IR-A) is relevant because presents recognized biological effects, such as antioxidant, neuroprotective and antitumor effects. Glioblastoma is the most aggressive central nervous system (CNS) neoplasm with high proliferation and tissue invasion capacity and is resistant to radio and chemotherapy. Here, we evaluated in vitro the possible interaction of temozolomide (TMZ) with IR-A in a glioblastoma cell line (C6) and in a human keratinocyte cell line (HaCat) how non-tumor cell model, in an attempt to search for a new treatment strategy. The effects of TMZ, IR-A and the interaction between TMZ and IR-A was evaluated by viability exclusion with trypan blue. To perform the interaction experiments, we have chosen 10 µM TMZ and 4.5 J/cm2 of IR-A. From this, we evaluated cytotoxicity, cell proliferation, intracellular reactive oxygen species levels (ROS), as well as the process of cell migration and the P-gp and MRP-1 activity. Cell death mainly due to apoptosis, followed by necrosis, decreased cell proliferation, increased ROS levels, decreased cell migration and decreased P-gp and MRP1 activity were observed only when there was interaction between TMZ and IR-A in the C6 cell line. The interaction between TMZ and IR-A was not able to affect cell proliferation in the HaCat non-tumor cell line. Our results suggest that this interaction could be a promising approach and that in the future may serve as an antitumor strategy for PDT application.

Cardioprotective effect of eicosapentaenoic acid during ischemia and reperfusion / Efeito cardioprotetor do ácido eicosapentaenóico durante a isquemia e reperfusão

Objective: In this work, rats isolated hearts were infused EPA before the ischemia period and during reperfusion for available get well in parameter relatives to redox reactions. Methods: The effect of EPA was tested on isolated hearts induced to ischemia and reperfusion, treatment occurred at different times (ischemia or reperfusion). Antioxidant capacity against peroxyl radicals, glutathione cysteine ligase activity, glutathione concentration, lactate dehydrogenase, and creatine kinase concentration was analyzed. Results: Hearts treated with eicosapentaenoic acid had the minor generation of species reactive oxygen and lipid damage after reperfusion. The GSH concentration was higher when the hearts were treated with eicosapentaenoic acid in the period of reperfusion. Conclusion: In conclusion, this study demonstrates that the dose of EPA (20µM) used before ischemia can act as a cardioprotective antioxidant molecule, prevented damage heart from ischemic and reperfusion injury

Objetivo: Neste trabalho, corações isolados de ratos foram infundidos com EPA antes do período de isquemia e durante a reperfusão para obtenção de melhora em parâmetros relativos às reações redox. Métodos: O efeito do EPA foi testado em corações isolados induzidos a isquemia e reperfusão, o tratamento ocorreu em diferentes momentos (isquemia ou reperfusão). A capacidade antioxidante contra os radicais peroxil, atividade da glutationa cisteína ligase, concentração de glutationa, lactato desidrogenase e concentração de creatina quinase foi analisada. Resultados: Corações tratados com ácido eicosapentaenóico tiveram a menor geração de espécies reativas de oxigênio e danos lipídicos após a reperfusão. A concentração de GSH foi maior quando os corações foram tratados com ácido eicosapentaenóico no período de reperfusão. Conclusão: Em conclusão, este estudo demonstra que a dose de EPA (20µM) utilizada antes da isquemia pode atuar como uma molécula antioxidante cardioprotetora, prevenindo danos ao coração por isquemia e lesão de reperfusão.

New Mechanistic Insight on the PIM-1 Kinase Inhibitor AZD1208 Using Multidrug Resistant Human Erythroleukemia Cell Lines and Molecular Docking Simulations.

BACKGROUND: PIM-1 is a kinase which has been related to the oncogenic processes like cell survival, proliferation, and multidrug resistance (MDR). This kinase is known for its ability to phosphorylate the main extrusion pump (ABCB1) related to the MDR phenotype. OBJECTIVE: In the present work, we tested a new mechanistic insight on the AZD1208 (PIM-1 specific inhibitor) under interaction with chemotherapy agents such as Daunorubicin (DNR) and Vincristine (VCR). MATERIALS AND METHODS: In order to verify a potential cytotoxic effect based on pharmacological synergism, two MDR cell lines were used: Lucena (resistant to VCR) and FEPS (resistant to DNR), both derived from the K562 non-MDR cell line, by MTT analyses. The activity of Pgp was ascertained by measuring accumulation and the directional flux of Rh123. Furthermore, we performed a molecular docking simulation to delve into the molecular mechanism of PIM-1 alone, and combined with chemotherapeutic agents (VCR and DNR). RESULTS: Our in vitro results have shown that AZD1208 alone decreases cell viability of MDR cells. However, co-exposure of AZD1208 and DNR or VCR reverses this effect. When we analyzed the ABCB1 activity AZD1208 alone was not able to affect the pump extrusion. Differently, co-exposure of AZD1208 and DNR or VCR impaired ABCB1 activity, which could be explained by compensatory expression of abcb1 or other extrusion pumps not analyzed here. Docking analysis showed that AZD1208 is capable of performing hydrophobic interactions with PIM-1 ATP- binding-site residues with stronger interaction-based negative free energy (FEB, kcal/mol) than the ATP itself, mimicking an ATP-competitive inhibitory pattern of interaction. On the same way, VCR and DNR may theoretically interact at the same biophysical environment of AZD1208 and also compete with ATP by the PIM-1 active site. These evidences suggest that AZD1208 may induce pharmacodynamic interaction with VCR and DNR, weakening its cytotoxic potential in the ATP-binding site from PIM-1 observed in the in vitro experiments. CONCLUSION: Finally, the current results could have a pre-clinical relevance potential in the rational polypharmacology strategies to prevent multiple-drugs resistance in human leukemia cancer therapy.

Silencing the OCT4-PG1 pseudogene reduces OCT-4 protein levels and changes characteristics of the multidrug resistance phenotype in chronic myeloid leukemia.

Cancer stem cells show epigenetic plasticity and intrinsic resistance to anti-cancer therapy, rendering capable of initiating cancer relapse and progression. Transcription factor OCT-4 regulates various pathways in stem cells, but its expression can be regulated by pseudogenes. This work evaluated how OCT4-PG1 pseudogene can affect OCT-4 expression and mechanisms related to the multidrug resistance (MDR) phenotype in FEPS cells. Considering that OCT-4 protein is a transcription factor that regulates expression of ABC transporters, level of gene expression, activity of ABC proteins and cell sensitivity to chemotherapy were evaluated after OCT4-PG1 silencing. Besides we set up a STRING network. Results showed that after OCT4-PG1 silencing, cells expressed OCT-4 gene and protein to a lesser extent than mock cells. The gene and protein expression of ABCB1, as well as its activity were reduced. On the other hand, ALOX5 and ABCC1 genes was increased even as the activity of this transporter. Moreover, the silencing cells become sensitive to two chemotherapics tested. The network structure demonstrated that OCT4-PG1 protein interacts directly with OCT-4, SOX2, and NANOG and indirectly with ABC transporters. We conclude that OCT4-PG1 pseudogene plays a key role in the regulation OCT-4 transcription factor, which alters MDR phenotype in the FEPS cell line.

Multidrug resistance phenotype: Relation between phenotype induction and its characteristics in erythroleukemia cells.

Chemotherapy may be followed by multiple drug resistance (MDR). This is an obstacle in the treatment of cancer. It is therefore essential to understand the mechanisms underlying tumor resistance, especially those involved in the cell target/MDR relationship. To investigate this, the effects of exposing cells to UVB (to target DNA), UVA, and H2 O2 (to target the cell membrane) were observed in K562 (non MDR) and FEPS (MDR) cell lines. The K562 cells were more sensitive to UVA than the FEPS cells. The FEPS cell line was more resistant to H2 O2 than K562, only presenting cytotoxicity 72 h after being exposed to 40 mM, with no ROS increase until 48 h. Both cell lines were sensitive to UVB, presenting cytotoxicity after 24 h, mainly by apoptosis, and showed an increase in ROS levels. Our results indicate that agents acting on DNA may be able to overcome the MDR phenotype.

Combination of ω-3 fatty acids and cisplatin as a potential alternative strategy for personalized therapy of metastatic melanoma: an in-vitro study.

The recently developed therapeutic strategies have led to unprecedented improvements in the control of metastatic melanoma and in the survival of specific subgroups of patients. However, drug resistance, low response rates, and undesired side effects make these treatments not suitable or tolerable for all the patients, and chemotherapeutic treatments appear still indispensable, at least for subgroups of patients. New combinatory strategies are also under investigation as tailored treatments or salvage therapies, including combined treatments of immunotherapy with conventional chemotherapy. On this basis, and in consideration of the antineoplastic properties of ω-3 polyunsaturated fatty acids, we have here investigated the potential of these bioactive dietary factors to revert the resistance frequently exhibited by this form of cancer to cisplatin (CDDP, cis-diamminedichloroplatinum). We demonstrated that docosahexenoic acid (DHA, 22:6ω-3) sensitizes the cells to the CDDP-induced inhibition of cell growth and migration by reverting CDDP effects on DNA damage and ERCC1 expression, as well as on the DUSP6 and p-ERK expressions, which regulate ERCC1 activation upwardly. In line, DUSP6 gene silencing prevented the effect of DHA, confirming that DHA acted on the DUSP6/p-ERK/ERCC1 repair pathways to sensitize melanoma cells to the anticancer effect of CDDP. Similar effects were obtained also with eicosapentaenoic acid (20:5ω-3). Overall, our findings suggest that the combination of CDDP treatment with a dietary supplementation with ω-3 polyunsaturated fatty acids could potentially represent a new therapeutic strategy for overcoming CDDP resistance in metastatic melanoma.

C-Phycocyanin: Cellular targets, mechanisms of action and multi drug resistance in cancer.

C-Phycocyanin (C-PC) has been shown to be promising in cancer treatment; however, although several articles detailing this have been published, its main mechanisms of action and its cellular targets have not yet been defined, nor has a detailed exploration been conducted of its role in the resistance of cancer cells to chemotherapy, rendering clinical use impossible. From our extensive examination of the literature, we have determined as our main hypothesis that C-PC has no one specific target, but rather acts on the membrane, cytoplasm, and nucleus with diverse mechanisms of action. We highlight the cell targets with which C-PC interacts (the MDR1 gene, cytoskeleton proteins, and COX-2 enzyme) that make it capable of killing cells resistant to chemotherapy. We also propose future analyses of the interaction between C-PC and drug extrusion proteins, such as ABCB1 and ABCC1, using in silico and in vitro studies.

Cytoprotection of lipoic acid against toxicity induced by saxitoxin in hippocampal cell line HT-22 through in silico modeling and in vitro assays.

Saxitoxins (STXs) are potent neurotoxins that block voltage-gated channels in neurons and induce cytotoxicity. These toxins not only can generate reactive oxygen species but also can alter antioxidant levels, promoting oxidative stress. Under this pro-oxidant situation, the use of the antioxidant lipoic acid (LA) can represent a chemoprotective alternative to minimize the deleterious effects induced by neurotoxins as STXs. P-glycoprotein (P-gp) is a well-known ATP-binding cassette (ABC) transporter that plays a crucial role in the extrusion of toxic substances, decreasing their accumulation and potential intracellular effects in virtue of its broad substrate specificity, its expression in many excretory tissues and its large efflux capacity. The interaction of STXs with LA was evaluated by ab initio simulation, molecular docking and bioassays using the cell line HT-22. The interaction of STXs with LA occurs by physisorption. Molecular docking indicated that STXs can be a substrate of P-gp and, estimating the Free Energy of Binding (FEB), LA has lower amino acids residues binding sites, similar to verapamil, while STX and STX+LA_1 have similar amino acids residues and binding sites with similar FEB between this ligands.Cells were exposed to STXs and LA for 30min and 24h. LA treatment minimizes STX cytotoxicity, evaluated by trypan blue and MTT assay and both STX and STX-LA treatments were efficient to induce P-gp activity measured by rhodamine 123 dye extrusion. LA and STX+LA treatments induced low reactive oxygen species levels and low oxygen consumption. Based on our results, it can be concluded that LA was able to induce cytoprotection, including induction of cellular glutathione levels, and that STX+LA interaction reduced toxicity effects induced by STX. Overall, the in vitro results corroborated the semi-empirical evidences found using density functional theory ab initio simulation and molecular docking.

Fatty-monastrol derivatives and its cytotoxic effect against melanoma cell growth.

Melanoma is the most dangerous type of skin cancer due to the occurrence of metastases. This work is aimed at studying the effects of the insertion of palmitic and oleic acid chain into monastrol in the melanoma cell line, B16F10. Cells were treated with monastrol, palmitic-monastrol or oleic-monastrol for periods of 0, 24, 48 and 72 h, and the cytotoxic effect was observed for palmitic-monastrol and oleic-monastrol after 24 h. For monastrol the effects were observed in 48 h on B16F10 cells, and in 24 h for a non-tumour cell line, melan-a. In this cell line, fatty-monastrol derivatives were cytotoxic after 24 h of exposure in the same concentrations as B16F10. However, oleic-monastrol inhibited cell growth at 20µM only after 72 h, in contrast to the B16F10 cell line, in which oleic-monastrol inhibited cell growth at 48 h, showing that at least in this structural modification, melan-a was less sensitive than B16F10. The ability of compounds to induce apoptosis and/or necrosis was measured, and it was observed that monastrol induces apoptosis within 24 h. However, the cells treated with fatty-monastrol derivatives did not remain adhered on the well plate after 3 h of treatment. At this time point, these cells still emitted fluorescence indicating viable cells, suggesting a possible effect of palmitic- and oleic-monastrol in the adhesion proteins found on the cell membrane.

Protective role of the novel hybrid 3,5-dipalmitoyl-nifedipine in a cardiomyoblast culture subjected to simulated ischemia/reperfusion.

This work investigated the acute effects of the calcium channel blocker nifedipine and its new fatty hybrid derived from palmitic acid, 3,5-dipalmitoyl-nifedipine, compared to endocannabinoid anandamide during the process of inducing ischemia and reperfusion in cardiomyoblast H9c2 heart cells. The cardiomyoblasts were treated in 24 or 96-well plates (according to the test being performed) and maintaining the treatment until the end of hypoxia induction. The molecules were tested at concentrations of 10 and 100µM, cells were treated 24h after assembling the experimental plates and immediately before the I/R. Cell viability, apoptosis and necrosis, and generation of reactive oxygen species were evaluated. Nifedipine and 3,5-dipalmitoyl-nifedipine were used to assess radical scavenging potential and metal chelation. All tested molecules managed to reduce the levels of reactive oxygen species compared to the starvation+vehicle group. In in vitro assays, 3,5-dipalmitoyl-nifedipine showed more antioxidant activity than nifedipine. These results indicate the ability of this molecule to act as a powerful ROS scavenger. Cell viability was highest when cells were induced to I/R by both concentrations of anandamide and the higher concentration of DPN. These treatments also reduced cell death. Therefore, it was demonstrated that the process of hybridization of nifedipine with two palmitic acid chains assigns a greater cardioprotective effect to this molecule, thereby reducing the damage caused by hypoxia and reoxygenation in cardiomyoblast cultures.