Proteomic Dynamics of Multidrug Resistance Mechanisms in Lucena 1 Cell Line.

The Lucena 1 cell line, derived from the human chronic myeloid leukemia cell line K562 under selective pressure of vincristine supplementation, exhibits multidrug resistance (MDR). This study aims to explore and elucidate the underlying mechanisms driving MDR in the Lucena 1 cell line. A proteomic analysis comparing K562 and Lucena 1 revealed qualitative differences, with a focus on the ATP-dependent efflux pump, Translocase ABCB1, a key contributor to drug resistance. Tubulin analysis identified two unique isoforms, Tubulin beta 8B and alpha chain-like 3, exclusive to Lucena 1, potentially influencing resistance mechanisms. Additionally, the association of Rap1A and Krit1 in cytoskeletal regulation and the presence of STAT1, linked to the urea cycle and tumor development, offered insights into Lucena 1's distinctive biology. The increased expression of carbonic anhydrase I suggested a role in pH regulation. The discovery of COP9, a tumor suppressor targeting p53, further highlighted the Lucena 1 complex molecular landscape. This study offers new insights into the MDR phenotype and its multifactorial consequences in cellular pathways. Thus, unraveling the mechanisms of MDR holds promise for innovating cancer models and antitumor targeted strategies, since inhibiting the P-glycoprotein (P-gp)/ABCB1 protein is not always an effective approach given the associated treatment toxicity.

FRAX486, a PAK inhibitor, overcomes ABCB1-mediated multidrug resistance in breast cancer cells.

The overexpression of P-glycoprotein (P-gp/ABCB1) is a leading cause of multidrug resistance (MDR). Hence, it is crucial to discover effective pharmaceuticals that counteract ABCB1-mediated multidrug resistance. FRAX486 is a p21-activated kinase (PAK) inhibitor. The objective of this study was to investigate whether FRAX486 can reverse ABCB1-mediated multidrug resistance, while also exploring its mechanism of action. The CCK8 assay demonstrated that FRAX486 significantly reversed ABCB1-mediated multidrug resistance. Furthermore, western blotting and immunofluorescence experiments revealed that FRAX486 had no impact on expression level and intracellular localization of ABCB1. Notably, FRAX486 was found to enhance intracellular drug accumulation and reduce efflux, resulting in the reversal of multidrug resistance. Docking analysis also indicated a strong affinity between FRAX486 and ABCB1. This study highlights the ability of FRAX486 to reverse ABCB1-mediated multidrug resistance and provides valuable insights for its clinical application.

Fostensavir trometamol 600 mg para o tratamento de indivíduos adultos vivendo com HIV multirresistentes aos antirretrovirais / Fostensavir trometamol 600 mg for the treatment of individuals adults living with multidrug-resistant HIV

INTRODUÇÃO: O HIV-1 é um vírus que apresenta em seu envelope viral a glicoproteína gp120, capaz de se ligar aos receptores CD4+ dos linfócitos T do hospedeiro, inviabilizando o funcionamento normal ou levando à destruição das células do sistema imune da pessoa vivendo com esse agente infeccioso. No contexto do tratamento contra o vírus, as quasispécies de HIV-1 podem sofrer uma ou mais mutações genéticas que afetam a atividade de um ou mais ARVs que já foram efetivos anteriormente, processo que é denominado resistência. Segundo a Organização Mundial de Saúde (OMS), observa-se em diversos países que a resistência atinge mais de 10% dos indivíduos em início ou reinício do tratamento contra o HIV. PERGUNTA: Fostensavir 600 mg é eficaz, custo-efetivo e seguro no tratamento de pessoas adultas vivendo com HIV-1 multirresistente aos ARVs? EVIDÊNCIAS CLÍNICAS: A partir da pergunta de pesquisa, foi desenvolvida estratégia de busca nas bases de dados MEDLINE via PubMed e EMBASE. A busca realizada resultou em 318 publicações. Foram inicialmente excluídas 72 por serem duplicatas. Posteriormente, foram excluídas outras 220 após triagem. Após leitura dos textos completos, chegou-se ao resultado de cinco publicações elegíveis, todas fruto do ensaio clínico randomizado de fase III, BRIGHTE. Foram relatados os desfechos de média de redução de carga viral, resposta virológica, falha virológica, variação média de linfócitos T CD4+, eventos adversos, morte, qualidade de vida e adesão ao tratamento. Em geral, o nível de certeza das evidências foi classificado como baixo, com risco de viés grave. AVALIAÇÃO ECONÔMICA: Utilizando um modelo de árvore de decisão, foi realizada uma análise para estimar a razão de custo-efetividade incremental (RCEI) do fostensavir 600 mg para pessoas vivendo com HIV-Aids, adultos e com multirresistência a pelo menos quatro classes terapêuticas de antirretrovirais desde que combinado a pelo menos um ARV totalmente ativo para um ano. O modelo comparou o fostensavir à terapia de base otimizada (TBO) apresentada no estudo pivotal BRIGHTE. ANÁLISE DE IMPACTO ORÇAMENTÁRIO: Foram projetados dois cenários de incorporação para a difusão do fostensavir: conservador e moderado. No cenário de difusão conservador (market share 10% ao ano), o impacto da incorporação do fostensavir em cinco anos variou entre R$ 10.975.053,60 e R$ 65.109.874,58, de 2024 a 2028 respectivamente. O impacto orçamentário acumulado em cinco anos no cenário conservador foi R$ 185.241.468,80. No cenário de difusão moderado (market share 20% ao ano), o impacto da incorporação em cinco anos variou entre R$ 10.975.053,60 e R$ 117.197.774,25, de 2024 a 2028. O impacto orçamentário acumulado em cinco anos no cenário de difusão moderado foi R$ 310.435.446,95. Monitoramento do horizonte tecnológico: Foram identificadas duas tecnologias para o tratamento de pessoas adultas convivendo com HIV multirresistente. Lenacapavir, que está registrado nas agências EMA e FDA, e ibalizumabe, com registro na FDA. PERSPECTIVA DO PACIENTE: A chamada pública nº 30/2023 ficou aberta entre 14 e 24 de agosto de 2023. Duas pessoas se inscreveram. O representante titular contou que tem 50 anos e há 25 vive com HIV. Acredita já ter usado todas as classes de medicamentos por conta da multirresistência do HIV aos ARV, chegando a ficar sem opção terapêutica por cinco ou seis anos. Atualmente utiliza a combinação maraviroque, dolutegravir, tenofovir, lamivudina, darunavir e ritonavir, com a qual consegue obter a supressão da carga viral. Ressaltou que quem vive com HIV há muito tempo corre o risco de ficar sem opção de medicamentos e que a incorporação de novas tecnologias pode beneficiar pessoas como ele. RECOMENDAÇÃO PRELIMINAR DA CONITEC: Os membros do Comitê de Medicamentos presentes na 125ª Reunião Ordinária, realizada no dia 6 de dezembro de 2023, deliberaram, por unanimidade, encaminhar o tema para consulta pública com recomendação preliminar favorável à incorporação do fostensavir trometamol 600 mg para o tratamento de pessoas vivendo com HIV-Aids multirresistentes a terapia antirretroviral. Considerou-se a oportunidade de uma opção terapêutica aos indivíduos multirresitentes, a capacidade das Câmaras Técnicas Estaduais e da área técnica do Ministério da Saúde no monitoramento dos benefícios clínicos e dos eventos adversos do fostensavir e a expectativa de uma nova proposta de preço encaminhada pela empresa durante a consulta pública. CONSULTA PÚBLICA: A consulta pública (CP) nº 69/2023 foi realizada entre os dias 29/12/2023 e 17/01/2024. Foram recebidas 11 contribuições, sendo sete pelo formulário para contribuições técnico-científico e quatro pelo formulário pra contribuições sobre experiência ou opinião de pacientes, familiares, amigos ou cuidadores de pacientes, profissionais de saúde ou pessoas interessadas no tema. Sobre as contribuições técnicas, todas foram favoráveis às recomendações preliminares da Conitec e uma possuía referencial teórico para a abordagem técnico-científica. Entretanto, não se identificou nenhuma evidência científica adicional que pudesse modificar o entendimento preliminar da Conitec. Nas contribuições de experiência ou opinião, todos os participantes manifestaram-se favoráveis à recomendação preliminar da tecnologia avaliada. Os argumentos relevantes foram classificados em "Sobrevida do paciente", uma vez que a abordagem foi especificamente quanto às falhas terapêuticas do uso de outros antirretrovirais e a evolução para complicações e óbito. Metade dos respondedores apontaram ter experiência com o fostensavir. No que diz respeito à experiência com outras tecnologias, um dos três respondentes, o paciente, mencionou o uso de medicamentos, como tenofovir, lamivudina, efavirenz e dolutegravir e apontou como evento negativo os seus efeitos colaterais. Além disso, destacaram o valor elevado da aquisição do fostensavir como uma das principais dificuldades para acesso a este tratamento. NOVA PROPOSTA COMERCIAL: Foi submetida ao DGITS/SECTICS/MS o valor de USD 38,67 por comprimido, com uma quantidade mínima de aquisição estabelecida em 360.000 (trezentos e sessenta mil) unidades. Considerando o novo valor proposto, o custo mensal do tratamento será de R$ 11.513,40, representando aproximadamente 65,59% de desconto em relação ao preço CMED PMVG 18% e uma redução de 1,66% em relação à proposta apresentada em 2023. Ainda com base no novo valor proposto, atualizou-se a avaliação econômica e a AIO. Os critérios considerados englobam os termos da recente proposta comercial e a taxa de câmbio do dólar no dia 15 de fevereiro de 2024, fixada em 1 USD = R$ 4,9624. A RCEI foi estimada em R$ 257.370,65, apresentando uma efetividade incremental de 0,54. No cenário conservador da nova AIO, levando em consideração uma participação de mercado de 10% ao ano, o impacto orçamentário incremental em cinco anos foi R$ 100.714.577,75. Já no cenário moderado, com um aumento de 20% após o primeiro ano, o impacto orçamentário acumulado em cinco anos foi R$ 247.300.234,85. RECOMENDAÇÃO FINAL DA CONITEC: Os membros do Comitê de Medicamentos presentes na 127ª Reunião Ordinária, realizada no dia 6 de março de 2024, deliberaram, por unanimidade, recomendar a incorporação do fostensavir trometamol 600 mg para o tratamento de indivíduos adultos vivendo com HIV multirresistentes aos antirretrovirais, conforme Protocolo Clínico do Ministério da Saúde. Considerou-se as expectativas da ampliação das opções terapêuticas e da redução da carga viral aos pacientes multirresistentes. Foi assinado o Registro de Deliberação nº 881/2024. DECISÃO: incorporar, no âmbito do Sistema Único de Saúde - SUS, o fostensavir trometamol 600 mg para o tratamento de indivíduos adultos vivendo com HIV multirresistente aos antirretrovirais, conforme Protocolo Clínico do Ministério da Saúde, publicada no Diário Oficial da União nº 77, seção 1, página 177, em 22 de abril de 2024.

Resistencia antimicrobiana, una pandemia silenciosa / Antimicrobial resistance, a silent pandemic / Resistência antimicrobiana, uma pandemia silenciosa

Introducción: la resistencia a los antimicrobianos ha sido una problemática creciente a nivel global, la problemática afecta no solo la salud de personas, animales y el ambiente en general, sino que ha generado impactos de índole productivo y comercial. Una de las estrategias para abordar esta problemática es el enfoque de una salud. Este enfoque destaca la participación multidisciplinaria para combatir la resistencia antimicrobiana; y es así que cada profesión o actividad laboral genera unas responsabilidades innatas para la profesión veterinaria. Los veterinarios tienen un rol fundamental para este propósito, ya que son ellos quienes integran la aplicabilidad de estrategias de promoción y prevención a nivel agropecuario, y de consolidación e interlocución entre los diferentes componentes del enfoque (animal, humano, ambiente) desde el ámbito de la salud pública veterinaria. Materiales y Método: se realizó una búsqueda de la literatura en diferentes bases de datos, con el objetivo de realizar una revisión actualizada sobre la resistencia antimicrobiana. Resultados: dentro de las principales estrategias se debería fomentar un uso adecuado y bajo prescripción de antimicrobianos en la producción animal. Promover buenas prácticas de higiene, bioseguridad y vacunación, facilitando un correcto diagnóstico de enfermedades infecciosas en animales. Discusión: la adopción de normas internacionales para el uso responsable de los antibióticos y las directrices establecidas por la Organización Mundial de la Salud y Organización de las Naciones Unidas para la Alimentación y la Agricultura, a través del Codex Alimentarius y la Organización Mundial de Sanidad Animal, son fundamentales para hacer frente al desafío que representa el problema de la resistencia a los antimicrobianos.

Introduction: Antimicrobial resistance has been a growing problem at a global level, affecting not only the health of people, animals and the environment in general, but it has also generated impacts of a productive and commercial nature. One of the strategies to address this problem is the one-health approach. This approach emphasizes multidisciplinary participation to combat antimicrobial resistance; and thus, each profession or work activity generates innate responsibilities for the veterinary profession. Veterinarians have a fundamental role for this purpose, since they are the ones who integrate the applicability of promotion and prevention strategies at the agricultural level, and of consolidation and interlocution between the different components of the approach (animal, human, environment) from the field of veterinary public health. Materials and Method: a literature search was carried out in different databases, with the aim of carrying out an updated review on antimicrobial resistance. Results: one of the main strategies should be to promote an adequate use and under prescription of antimicrobials in animal production. Promote good hygiene, biosecurity and vaccination practices, facilitating a correct diagnosis of infectious diseases in animals. Discussion: the adoption of international standards for the responsible use of antibiotics and the guidelines established by the World Health Organization and the Food and Agriculture Organization of the United Nations, through Codex Alimentarius and the World Organization for Animal Health, are fundamental to face the challenge posed by the problem of antimicrobial resistance.

Introdução: A resistência antimicrobiana tem sido um problema crescente em todo o mundo, afetando não apenas a saúde dos seres humanos, dos animais e do meio ambiente em geral, mas também causando impactos na produção e no comércio. Uma das estratégias para lidar com esse problema é a abordagem One Health. Essa abordagem enfatiza o envolvimento multidisciplinar no combate à resistência antimicrobiana, com cada profissão ou atividade de trabalho gerando responsabilidades inatas à profissão veterinária. Os veterinários têm um papel fundamental nesse sentido, pois são eles que integram a aplicabilidade das estratégias de promoção e prevenção em nível agropecuário e de consolidação e interlocução entre os diferentes componentes da abordagem (animal, humano, ambiental) do campo da saúde pública veterinária. Materiais e Métodos: foi realizada uma pesquisa bibliográfica em diferentes bases de dados, com o objetivo de realizar uma revisão atualizada sobre a resistência antimicrobiana. Resultados: uma das principais estratégias deve ser a promoção do uso adequado e com baixa prescrição de antimicrobianos na produção animal. Promover boas práticas de higiene, biossegurança e vacinação, facilitando o diagnóstico correto de doenças infecciosas em animais. Discussão: A adoção de padrões internacionais para o uso responsável de antibióticos e as diretrizes estabelecidas pela Organização Mundial da Saúde e pela Organização das Nações Unidas para Agricultura e Alimentação, por meio do Codex Alimentarius e da Organização Mundial de Saúde Animal, são essenciais para enfrentar o desafio representado pelo problema da resistência antimicrobiana.

A new porphyrin as selective substrate-based inhibitor of breast cancer resistance protein (BCRP/ABCG2).

The ABCG2 transporter plays a pivotal role in multidrug resistance, however, no clinical trial using specific ABCG2 inhibitors have been successful. Although ABC transporters actively extrude a wide variety of substrates, photodynamic therapeutic agents with porphyrinic scaffolds are exclusively transported by ABCG2. In this work, we describe for the first time a porphyrin derivative (4B) inhibitor of ABCG2 and capable to overcome multidrug resistance in vitro. The inhibition was time-dependent and 4B was not itself transported by ABCG2. Independently of the substrate, the porphyrin 4B showed an IC50 value of 1.6 µM and a mixed type of inhibition. This compound inhibited the ATPase activity and increased the binding of the conformational-sensitive antibody 5D3. A thermostability assay confirmed allosteric protein changes triggered by the porphyrin. Long-timescale molecular dynamics simulations revealed a different behavior between the ABCG2 porphyrinic substrate pheophorbide a and the porphyrin 4B. Pheophorbide a was able to bind in three different protein sites but 4B showed one binding conformation with a strong ionic interaction with GLU446. The inhibition was selective toward ABCG2, since no inhibition was observed for P-glycoprotein and MRP1. Finally, this compound successfully chemosensitized cells that overexpress ABCG2. These findings reinforce that substrates may be a privileged source of chemical scaffolds for identification of new inhibitors of multidrug resistance-linked ABC transporters.

Structure activity relationships and the binding mode of quinolinone-pyrimidine hybrids as reversal agents of multidrug resistance mediated by P-gp.

P-gp-associated multidrug resistance is a major impediment to the success of chemotherapy. With the aim of finding non-toxic and effective P-gp inhibitors, we investigated a panel of quinolin-2-one-pyrimidine hybrids. Among the active compounds, two of them significantly increased intracellular doxorubicin and rhodamine 123 accumulation by inhibiting the efflux mediated by P-gp and restored doxorubicin toxicity at nanomolar range. Structure-activity relationships showed that the number of methoxy groups, an optimal length of the molecule in its extended conformation, and at least one flexible methylene group bridging the quinolinone to the moiety bearing the pyrimidine favored the inhibitory potency of P-gp. The best compounds showed a similar binding pattern and interactions to those of doxorubicin and tariquidar, as revealed by MD and hybrid QM/MM simulations performed with the recent experimental structure of P-gp co-crystallized with paclitaxel. Analysis of the molecular interactions stabilizing the different molecular complexes determined by MD and QTAIM showed that binding to key residues from TMH 4-7 and 12 is required for inhibition.

Inhibitors of Chemoresistance Pathways in Combination with Ara-C to Overcome Multidrug Resistance in AML. A Mini Review.

Acute myeloid leukemia (AML), the most common type of leukemia in older adults, is a heterogeneous disease that originates from the clonal expansion of undifferentiated hematopoietic progenitor cells. These cells present a remarkable variety of genes and proteins with altered expression and function. Despite significant advances in understanding the molecular panorama of AML and the development of therapies that target mutations, survival has not improved significantly, and the therapy standard is still based on highly toxic chemotherapy, which includes cytarabine (Ara-C) and allogeneic hematopoietic cell transplantation. Approximately 60% of AML patients respond favorably to these treatments and go into complete remission; however, most eventually relapse, develop refractory disease or chemoresistance, and do not survive for more than five years. Therefore, drug resistance that initially occurs in leukemic cells (primary resistance) or that develops during or after treatment (acquired resistance) has become the main obstacle to AML treatment. In this work, the main molecules responsible for generating chemoresistance to Ara-C in AML are discussed, as well as some of the newer strategies to overcome it, such as the inclusion of molecules that can induce synergistic cytotoxicity with Ara-C (MNKI-8e, emodin, metformin and niclosamide), subtoxic concentrations of chemotherapy (PD0332991), and potently antineoplastic treatments that do not damage nonmalignant cells (heteronemin or hydroxyurea + azidothymidine).

Synthetic antimicrobial peptides: Characteristics, design, and potential as alternative molecules to overcome microbial resistance.

Recently, the dramatic emergence of antimicrobial resistance has received attention from World Health Organization. Synthetic antimicrobial peptides (SAMPs) are considered new weapons to fight against infections caused by multi-drug resistant pathogens. Here, the authors provide an overview of the current research on SAMPs. The focus is SAMPs, how to design them, which features must be considered during design, and comparison with natural peptides. This review also includes a discussion about the natural AMPs, mechanisms of action and applications as new drugs or even as adjuvants molecules to enhance commercial drugs activity. The advances in chemical synthesis have reduced the cost to produce synthetic peptides open ways to achieve new antimicrobial agents. Therefore, synthetic peptides are new promising molecules to safeguard human and animal health.

Selective Cytotoxicity of Piperine Over Multidrug Resistance Leukemic Cells.

Multidrug resistance (MDR) is the main challenge in the treatment of chronic myeloid leukemia (CML), and P-glycoprotein (P-gp) overexpression is an important mechanism involved in this resistance process. However, some compounds can selectively affect MDR cells, inducing collateral sensitivity (CS), which may be dependent on P-gp. The aim of this study was to investigate the effect of piperine, a phytochemical from black pepper, on CS induction in CML MDR cells, and the mechanisms involved. The results indicate that piperine induced CS, being more cytotoxic to K562-derived MDR cells (Lucena-1 and FEPS) than to K562, the parental CML cell. CS was confirmed by analysis of cell metabolic activity and viability, cell morphology and apoptosis. P-gp was partially required for CS induction. To investigate a P-gp independent mechanism, we analyzed the possibility that poly (ADP-ribose) polymerase-1 (PARP-1) could be involved in piperine cytotoxic effects. It was previously shown that only MDR FEPS cells present a high level of 24 kDa fragment of PARP-1, which could protect these cells against cell death. In the present study, piperine was able to decrease the 24 kDa fragment of PARP-1 in MDR FEPS cells. We conclude that piperine targets selectively MDR cells, inducing CS, through a mechanism that might be dependent or not on P-gp.

Recent advances in co-delivery nanosystems for synergistic action in cancer treatment.

Nanocarrier delivery systems have been widely studied to carry unique or dual chemical drugs. The major challenge of chemotherapies is to overcome the multidrug-resistance (MDR) of cells to antineoplastic medicines. In this context, nano-scale technology has allowed researchers to develop biocompatible nano-delivery systems to overcome the limitation of chemical agents. The development of nano-vehicles may also be directed to co-deliver different agents such as drugs and genetic materials. The delivery of nucleic acids targeting specific cells is based on gene therapy principles to replace the defective gene, correct genome errors or knock-down a particular gene. Co-delivery systems are attractive strategies due to the possibility of achieving synergistic therapeutic effects, which are more effective in overcoming the MDR of cancer cells. These combined therapies can provide better outcomes than separate delivery approaches carrying either siRNA, miRNA, pDNA, or drugs. This article reviews the main design features that need to be associated with nano-vehicles to co-deliver drugs, genes, and gene-drug combinations with efficacy. The advantages and disadvantages of co-administration approaches are also overviewed and compared with individual nanocarrier systems. Herein, future trends and perspectives in designing novel nano-scale platforms to co-deliver therapeutic agents are also discussed.

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.

Benzofuroxan Derivatives as Potent Agents against Multidrug-Resistant Mycobacterium tuberculosis.

Tuberculosis (TB) is currently the leading cause of death related to infectious diseases worldwide, as reported by the World Health Organization. Moreover, the increasing number of multidrug-resistant tuberculosis (MDR-TB) cases has alarmed health agencies, warranting extensive efforts to discover novel drugs that are effective and also safe. In this study, 23 new compounds were synthesized and evaluated in vitro against the drug-resistant strains of M. tuberculosis. The compound 6-((3-fluoro-4-thiomorpholinophenyl)carbamoyl)benzo[c][1,2,5]oxadiazole 1-N-oxide (5 b) was particularly remarkable in this regard as it demonstrated MIC90 values below 0.28 µM against all the MDR strains evaluated, thus suggesting that this compound might have a different mechanism of action. Benzofuroxans are an attractive new class of anti-TB agents, exemplified by compound 5 b, with excellent potency against the replicating and drug-resistant strains of M. tuberculosis.

Cell death and biomass reduction in biofilms of multidrug resistant extended spectrum ß-lactamase-producing uropathogenic Escherichia coli isolates by 1,8-cineole.

Escherichia coli is the most frequent agent of urinary tract infections in humans. The emergence of uropathogenic multidrug-resistant (MDR) E. coli strains that produce extended spectrum ß-lactamases (ESBL) has created additional problems in providing adequate treatment of urinary tract infections. We have previously reported the antimicrobial activity of 1,8-cineole, one of the main components of Rosmarinus officinalis volatile oil, against Gram negative bacteria during planktonic growth. Here, we evaluated the antibiofilm activity of 1,8-cineole against pre-formed mature biofilms of MDR ESBL-producing uropathogenic E. coli clinical strains by carrying out different technical approaches such as counting of viable cells, determination of biofilm biomass by crystal violet staining, and live/dead stain for confocal microscopy and flow cytometric analyses. The plant compound showed a concentration- and time-dependent antibiofilm activity over pre-formed biofilms. After a 1 h treatment with 1% (v/v) 1,8-cineole, a significant decrease in viable biofilm cell numbers (3-log reduction) was observed. Biofilms of antibiotic-sensitive and MDR ESBL-producing E. coli isolates were sensitive to 1,8-cineole exposure. The phytochemical treatment diminished the biofilm biomass by 48-65% for all four E. coli strain tested. Noteworthy, a significant cell death in the remaining biofilm was confirmed by confocal laser scanning microscopy after live/dead staining. In addition, the majority of the biofilm-detached cells after 1,8-cineole treatment were dead, as shown by flow cytometric assessment of live/dead-stained bacteria. Moreover, phytochemical-treated biofilms did not fully recover growth after 24 h in fresh medium. Altogether, our results support the efficacy of 1,8-cineole as a potential antimicrobial agent for the treatment of E. coli biofilm-associated infections.

Perfil de resistencia del Mycobacterium tuberculosis a fármacos antituberculosos de primera línea y sus combinaciones / Resistance profile of Mycobacterium tuberculosis to first-line antituberculosis drugs and their combinations

Introducción: En Colombia el control de la tuberculosis se ha visto amenazado por la resistencia a los fármacos antituberculosos y especialmente la tuberculosis multidrogorresistente. Objetivo: Determinar la resistencia global y perfiles de resistencia del Mycobacterium tuberculosis a fármacos antituberculosos de primera línea y combinaciones. Métodos: Estudio descriptivo, transversal, en el que se evaluaron 2 701 pacientes con tuberculosis en el Departamento del Atlántico (Colombia), durante los años 2011 a 2016. Se valoraron aspectos sociodemográficos, clínicos y condiciones de riesgo. Se realizó análisis de frecuencias relativas y absolutas, diferencia de proporciones ((2) y razón de prevalencias. Resultados: El 66,5 por ciento de los pacientes eran hombres, el 53 por ciento tenían entre 15 y 44 años de edad. El 47,34 por ciento con pérdida en el seguimiento y el 11,62 por ciento monorresistentes a isoniacida. La resistencia en casos nuevos fue 7,30 por ciento (IC95 por ciento: 6,3-8,5), para este grupo la multidrogorresistencia fue de 1,1 por ciento; mientras que en los previamente tratados la resistencia fue de 18,27 por ciento (IC95 por ciento: 15,6- 22,4) y la multidrogorresistencia de 5,7 por ciento. Los factores asociados a resistencia fueron presencia de VIH/TB (RP= 2,6; p= 0,000), otros factores inmunosupresores (RP= 3,5; p= 0,009), contacto de paciente con tuberculosis multidrogorresistente (RP= 16; p= 0,000) y caso previamente tratado (RP= 2,24; p= 0,00). Conclusiones: Se evidencia un descenso en la resistencia global a rifampicina e isoniacida, así como en la prevalencia multidrogorresistente tanto en casos nuevos como en previamente tratados en la población estudiada; lo que genera una línea base para la toma de decisiones que permita continuar mejorando la vigilancia y control de la resistencia del M. tuberculosis a fármacos de primera línea, debido a los nuevos retos que este microorganismo representa para la salud pública(AU)

Introduction: Tuberculosis control in Colombia has been hampered by resistance to antituberculosis drugs and particularly by multi-drug resistant tuberculosis. Objective: Determine the overall resistance and resistance profiles of Mycobacterium tuberculosis to first-line antituberculosis drugs and their combinations. Methods: A descriptive cross-sectional study was conducted of 2 701 tuberculosis patients from Atlántico Department in Colombia in the period 2011-2016. The evaluation included sociodemographic aspects, clinical characteristics and risk conditions. Data analysis was based on relative and absolute frequencies, proportion difference (x2) and prevalence ratio. Results: Of the total sample, 66.5 percent were men and 53 percent were aged 15-44 years. 47.34 percent were lost to follow-up and 11.62 percent were monoresistant to isoniazid. In new cases resistance was 7.30 percent (CI 95 percent: 6.3-8.5) and multi-drug resistance was 1.1 percent, whereas in previously treated cases resistance was 18.27 percent (CI 95 percent: 15.6-22.4) and multi-drug resistance was 5.7 percent. The factors associated to resistance were the presence of HIV/TB (AR= 2.6; p= 0.000), other immunosuppressive factors (AR= 3.5; p= 0.009), contact with multi-drug resistant tuberculosis patient (AR= 16; p= 0.000) and previously treated case (AR= 2.24; p= 0.00). Conclusions: A reduction is observed in overall resistance to rifampicin and isoniazid, as well as in the prevalence of multi-drug resistance, both in new cases and in previously treated cases, which creates a baseline for the taking of decisions aimed at the continuing improvement of the surveillance and control of M. tuberculosis resistance to first-line drugs, due to the new challenges posed by this microorganism to public health(AU)

Kalanchoe brasiliensis Cambess., a Promising Natural Source of Antioxidant and Antibiotic Agents against Multidrug-Resistant Pathogens for the Treatment of Salmonella Gastroenteritis.

Kalanchoe brasiliensis Cambess. is a native Brazilian plant popularly known as "saião", and the juice of its fresh leaves is traditionally used to treat several disorders, including inflammatory and infectious processes such as dysentery. The goals of this study were to characterize the phytochemical composition and investigate the antioxidant activity, the antibiotic effect, and the mode of action against Salmonella of the hydroethanolic extracts from K. brasiliensis leaves collected in the summer and spring Brazilian seasons. These extracts had their chemical composition established by high-performance liquid chromatography with diode-array detection. Total phenolic and flavonoid contents were spectrophotometrically determined. 2,2-Diphenyl-1-picryl-hydrazyl radical scavenging, phosphomolybdenum reducing power and ß-carotene bleaching assays were carried out to evaluate the antioxidant capacity. Antibiotic potential was assessed by minimal inhibitory concentration against 8 bacterial ATCC® and 5 methicillin-resistant Staphylococcus aureus and 5 Salmonella clinical strains. The mode of action was investigated by time-kill, bacterial cell viability, and leakage of compounds absorbing at 280 nm assays against Salmonella. Chromatographic profile and UV spectrum analyses suggested the significant presence of flavonoid type patuletin and eupafolin derivatives, and no difference between both periods of collection was noted. Significant amounts of total phenolic and flavonoid contents and a promising antioxidant capacity were observed. Hydroethanolic extracts (70%, summer and spring) were the most active against the tested Gram-positive and Gram-negative bacterial strains, showing the bacteriostatic action of 5000 µg/mL. Time-kill data demonstrated that these extracts were able to reduce the Salmonella growth rate. Cell number was reduced with release of the bacterial content. Together, these results suggest that K. brasiliensis is a natural source of antioxidant and antibacterial agents that can be applied in the research and development of new antibiotics for the treatment of Salmonella gastroenteritis because they are able to interfere in the Salmonella growth, probably due to cell membrane damage.

F127 poloxamer effect on cytotoxicity induction of tumour cell cultures treated with doxorubicin.

INTRODUCTION: Hepatocellular carcinoma is the most common liver malignancy and the third leading cause of cancer death worldwide. One crucial limitation in the pharmacotherapy for this tumour is its chemotherapy-resistant nature produced by the overexpression of several members of the ATP-binding cassette protein family that efflux drugs out of cells, as observed with the breast cancer resistant protein (BCRP). OBJECTIVES: This study aimed to assess the ability of Pluronic® F127 to reverse the multidrug resistance phenotype in two human hepatocellular cell lines. METHODS: PLC/PRF/5 and SKHep1 cells were exposed to Pluronic® F127 at several concentrations. The effect of F127 on BCRP expression (mRNA and protein), mitochondrial transmembrane potential and cell hypodiploidy was assessed. Finally, the effect of this copolymer on cytotoxicity of doxorubicin in both hepatoma cell lines was investigated, as expressed by its reverse resistance index. KEY FINDINGS: It was demonstrated that F127 in both cell lines contributes to chemosensitization, as shown by BCRP down-regulation, an altered mitochondrial transmembrane potential and hypodiploidy and reverse resistance index values. A remarkable dependence of these effects significantly correlated with the copolymer concentration. CONCLUSIONS: These findings further uncover the potential usefulness of this copolymer as multidrug resistance reversal agent, increasing the efficacy of cancer therapies.

Chemo-sensitizing activity of natural cadinanes from Heterotheca inuloides in human uterine sarcoma cells and their in silico interaction with ABC transporters.

Sensitizing activities exerted by 3,4-dihydro-7-hydroxycadalene (1), rac-3,7-dihydroxy-3(4H)-isocadalen-4-one (4) and (1R,4R)-4H-1,2,3,4-tetrahydro-1-hydroxycadalen-15-oic acid (9), the major cadinanes isolated from Heterotheca inuloides, towards multidrug-resistant MES-SA/MX2 and parental MES-SA epithelial human uterine sarcoma cell lines were evaluated. We also evaluated the in silico interactions (expressed as ΔGbinding in kcal/mol) of cadinanes 1, 4 and 9 in an in vitro assay, and also tested several structurally related natural compounds with the multidrug resistance protein (MDR1, P-glycoprotein), human multidrug resistance protein 1 (MRP1), and breast cancer resistance protein (BCRP) structures as pharmacological targets using AutoDock and AutoDock Vina. Compound 1 potentiated the cytotoxicity of doxorubicin and mitoxantrone drugs in resistant MES-SA/MX2 cells, compared to cells treated with each drug alone. Compound 1 could reverse the resistance to doxorubicin 12.44 fold at a concentration of 5 µM. It also re-sensitized cells to mitoxantrone 3.94 fold. Hence, compound 1 may be considered as a potential chemosensitizing agent to overcome multidrug resistance in cancer. The docking analysis suggested that there are interactions between cadinanes from H. inuloides and MDR1, MRP1, and BCRP proteins mainly through π-π interactions and hydrogen bonds.

Effects of the Natural Peptide Crotamine from a South American Rattlesnake on Candida auris, an Emergent Multidrug Antifungal Resistant Human Pathogen.

Invasive Candida infections are an important growing medical concern and treatment options are limited to a few antifungal drug classes, with limited efficacies depending on the infecting organism. In this scenario, invasive infections caused by multiresistant Candida auris are emerging in several places around the world as important healthcare-associated infections. As antimicrobial peptides (AMPs) exert their activities primarily through mechanisms involving membrane disruption, they have a lower chance of inducing drug resistance than general chemical antimicrobials. Interestingly, we previously described the potent candicidal effect of a rattlesnake AMP, crotamine, against standard and treatment-resistant clinical isolates, with no hemolytic activity. We evaluated the antifungal susceptibility of several Candida spp. strains cultured from different patients by using the Clinical and Laboratory Standards Institute (CLSI) microdilution assay, and the antifungal activity of native crotamine was evaluated by a microbial growth inhibition microdilution assay. Although all Candida isolates evaluated here showed resistance to amphotericin B and fluconazole, crotamine (40-80 µM) exhibited in vitro activity against most isolates tested. We suggest that this native polypeptide from the South American rattlesnake Crotalus durissus terrificus has potential as a structural model for the generation of a new class of antimicrobial compounds with the power to fight against multiresistant Candida spp.

TNF-α Modulates P-Glycoprotein Expression and Contributes to Cellular Proliferation via Extracellular Vesicles.

P-glycoprotein (Pgp/ABCB1) overexpression is associated with multidrug resistance (MDR) phenotype and, consequently, failure in cancer chemotherapy. However, molecules involved in cell death deregulation may also support MDR. Tumor necrosis factor-alpha (TNF-α) is an important cytokine that may trigger either death or tumor growth. Here, we examined the role of cancer cells in self-maintenance and promotion of cellular malignancy through the transport of Pgp and TNF-α molecules by extracellular vesicles (membrane microparticles (MP)). By using a classical MDR model in vitro, we identified a positive correlation between endogenous TNF-α and Pgp, which possibly favored a non-cytotoxic effect of recombinant TNF-α (rTNF-α). We also found a positive feedback involving rTNF-α incubation and TNF-α regulation. On the other hand, rTNF-α induced a reduction in Pgp expression levels and contributed to a reduced Pgp efflux function. Our results also showed that parental and MDR cells spontaneously released MP containing endogenous TNF-α and Pgp. However, these MP were unable to transfer their content to non-cancer recipient cells. Nevertheless, MP released from parental and MDR cells elevated the proliferation index of non-tumor cells. Collectively, our results suggest that Pgp and endogenous TNF-α positively regulate cancer cell malignancy and contribute to changes in normal cell behavior through MP.

The Diversified O-Superfamily in Californiconus californicus Presents a Conotoxin with Antimycobacterial Activity.

Californiconus californicus, previously named Conus californicus, has always been considered a unique species within cone snails, because of its molecular, toxicological and morphological singularities; including the wide range of its diet, since it is capable of preying indifferently on fish, snails, octopus, shrimps, and worms. We report here a new cysteine pattern conotoxin assigned to the O1-superfamily capable of inhibiting the growth of Mycobacterium tuberculosis (Mtb). The conotoxin was tested on a pathogen reference strain (H37Rv) and multidrug-resistant strains, having an inhibition effect on growth with a minimal inhibitory concentration (MIC) range of 3.52⁻0.22 µM, similar concentrations to drugs used in clinics. The peptide was purified from the venom using reverse phase high-performance liquid chromatography (RP-HPLC), a partial sequence was constructed by Edman degradation, completed by RACE and confirmed with venom gland transcriptome. The 32-mer peptide containing eight cysteine residues was named O1_cal29b, according to the current nomenclature for this type of molecule. Moreover, transcriptomic analysis of O-superfamily toxins present in the venom gland of the snail allowed us to assign several signal peptides to O2 and O3 superfamilies not described before in C. californicus, with new conotoxins frameworks.