resumo Existem no mundo cerca de 2.000 registros de ensaios clínicos para a investigação de medicamentos aprovados e outros candidatos para a Covid-19, incluindo moléculas pequenas e medicamentos biológicos, sem contar as vacinas. O reposicionamento de fármacos, estratégia mais explorada até o momento, não levou a qualquer novo tratamento antiviral contra a Covid-19. O remdesivir, apesar de sua aprovação emergencial pela agência reguladora norte-americana, apresentou somente resultados modestos em estudos clínicos. A dexametasona, que contribuiu para reduzir a mortalidade em pacientes graves recebendo ventilação mecânica invasiva ou oxigênio, é um corticoide que possui propriedades anti-inflamatórias e imunossupressoras. Os medicamentos biológicos, por sua vez, como anticorpos monoclonais, interferons, proteínas específicas e anticoagulantes estão sendo avaliados em diversas triagens clínicas para definir o seu papel na terapia da doença. A Organização Mundial da Saúde (OMS) alertou que o coronavírus poderá nunca desaparecer, mesmo com uma eventual vacina, evidenciando a urgência de pesquisas por novos fármacos inovadores. O cenário atual mais realista compreende o desenvolvimento de antivirais específicos contra o Sars-CoV-2 para o tratamento seguro e eficaz da doença.

abstract Approximately 2,000 clinical studies have been conducted in the world to investigate approved drugs and drug candidates for Covid-19, including small molecules and biologicals, not to mention vaccines. The repositioning of drugs, the most explored strategy, has not led to the identification of any new antiviral against Covid-19. Despite its approval for emergency use by the US regulatory agency, remdesivir has shown only modest results in clinical studies. Dexamethasone, which contributed to reduce mortality in critically ill patients receiving mechanical ventilation or oxygen, is a corticosteroid that has anti-inflammatory and immunosuppressive properties. Biological drugs, such as monoclonal antibodies, interferons, specific proteins, and anticoagulants are being evaluated in several clinical studies to assess their role in Covid-19 therapy. The World Health Organization (WHO) has warned that the coronavirus may never disappear even with the advent of an eventual vaccine, highlighting the urgency for the development of innovative drugs. The most realistic scenario involves the development of specific antivirals against Sars-CoV-2 for the safe and effective treatment of the disease.

Orbitides are a class of small naturally occurring cyclic peptides with structural and functional diversities. Their chemical properties make this class feasible to be obtained by solid phase peptide synthesis (SPPS). Therefore, this synthetic accessibility enables useful application and facilitates the identification of analogues, bioactivity studies, and thus, enables them to be applied to obtain peptide libraries. The aim of this work was to investigate the effects of orbitides and their linear synthetic analogues on the migration of neonatal human foreskin fibroblasts. The screening of linear peptide analogues, originally designed from natural orbitides isolated from Jatropha species, demonstrated that some molecules (linear pohlianin B and linear ribifolin) have the potential to induce fibroblast migration and collagen deposition and may thus contribute to accelerating the processes of wound healing and tissue repair. These results also demonstrate the significance of using peptides as an important tool for the discovery of simple and novel drug scaffolds.

Conjugated linoleic acid (CLA), a fatty acid found in ruminant food products, has been associated with anticarcinogenic activity. However, its effect on cancer metabolism is unclear. In this paper we evaluated the effects of cis-9, trans-11 CLA on the metabolic profile of MCF-7 and MDA-MB-231 breast cancer cells using high-resolution magic angle spinning (HR-MAS) nuclear magnetic resonance (NMR) spectroscopy. The NMR spectra showed that phosphocholine level, a cancer malignance biomarker, was reduced in both cells treated with CLA, but the reduction was more pronounced in MCF-7 cells. The NMR spectra also showed that CLA has opposite effect on MCF-7 and MDA-MB-231 acetone metabolism. Acetone signal has been observed in the spectra of MDA-MB-231 control cells, but not in the spectra of the cells treated with 50 and 100 µM CLA. Conversely, the acetone signal is very small or not observed in the NMR spectra of MCF-7 control cells and in cells treated with 50 µM of CLA, but is very strong in the spectra of the cells treated with 100 µM of CLA. Therefore, this CLA concentration is causing a ketosis in MCF-7 cells by inducing the use of fatty acids as an energy source or by reducing acetone catabolism. These results indicate that CLA interfere in the metabolism of both cells. However, the strongest effect has been observed on the metabolism of MCF-7 cells cultivated in the presence of 100 µM CLA. Therefore, CLA could be a potential anticarcinogenic drug, especially for cells with positive estrogen receptor, such as MCF-7.

ABSTRACT Scientific and technological breakthroughs have compelled the current players in drug discovery to increasingly incorporate knowledge-based approaches. This evolving paradigm, which has its roots attached to the recent advances in medicinal chemistry, molecular and structural biology, has unprecedentedly demanded the development of up-to-date computational approaches, such as bio- and chemo-informatics. These tools have been pivotal to catalyzing the ever-increasing amount of data generated by the molecular sciences, and to converting the data into insightful guidelines for use in the research pipeline. As a result, ligand- and structure-based drug design have emerged as key pathways to address the pharmaceutical industry’s striking demands for innovation. These approaches depend on a keen integration of experimental and molecular modeling methods to surmount the main challenges faced by drug candidates - in vivo efficacy, pharmacodynamics, metabolism, pharmacokinetics and safety. To that end, the Laboratório de Química Medicinal e Computacional (LQMC) of the Universidade de São Paulo has developed forefront research on highly prevalent and life-threatening neglected tropical diseases and cancer. By taking part in global initiatives for pharmaceutical innovation, the laboratory has contributed to the advance of these critical therapeutic areas through the use of cutting-edge strategies in medicinal chemistry.

ABSTRACT Cancer is one of the leading causes of death worldwide. With the increase in life expectancy, the number of cancer cases has reached unprecedented levels. In this scenario, the pharmaceutical industry has made significant investments in this therapeutic area. Despite these efforts, cancer drug research remains a remarkably challenging field, and therapeutic innovations have not yet achieved expected clinical results. However, the physiopathology of the disease is now better understood, and the discovery of novel molecular targets has refreshed the expectations of developing improved treatments. Several noteworthy advances have been made, among which the development of targeted therapies is the most significant. Monoclonal antibodies and antibody-small molecule conjugates have emerged as a worthwhile approach to improve drug selectivity and reduce adverse effects, which are the main challenges in cancer drug discovery. This review will examine the current panorama of drug research and development (R&D) with emphasis on some of the major advances brought to clinical trials and to the market in the past five years. Breakthrough discoveries will be highlighted along with the medicinal chemistry strategies used throughout the discovery process. In addition, this review will provide perspectives and updates on the discovery of novel molecular targets as well as drugs with innovative mechanisms of action.

Piperlongumine is a natural amide alkaloid isolated from several species of Piper and is described in the literature as selectively cytotoxic to several cancer cell lines. Inhibiting cell migration has gained considerable interest as an approach for discovering antimetastatic agents because this process is fundamental to metastasis. Piperlongumine, selected from cell-based assay screening of NuBBE Database, inhibited the migration of MDA-MB-231 breast cancer cells with an EC50 of 3.0 ± 1.0 µM by the Boyden chamber assay. A series of five analogous compounds based on the structure of piperlongumine were designed, synthesized and evaluated in cell migration and cytotoxicity assays. The analogue designed by molecular simplification ((E)-N-acryloyl-3-(3,4,5-trimethoxyphenyl)acrylamide) was the most active of the series, with an EC50 of 1.5 ± 1 µM. Additionally, this compound was selectively cytotoxic, with a selectivity index (SI) of 4.4.

A tripanossomíase africana, também conhecida como doença do sono, é responsável por um grande número de mortes na África. Até o presente, não há tratamento seguro e eficaz disponível. A enzima aldolase do parasita Trypanosoma brucei é um alvo atrativo e validado para o desenvolvimento de novos fármacos. Uma série de ésteres fosfóricos foi estudada com uma combinação de métodos de planejamento de fármacos. Modelos de relações quantitativas tridimensionais entre estrutura e atividade (3D QSAR) foram gerados empregando-se a análise comparativa de campos moleculares (CoMFA). Resultados significativos foram obtidos (r² = 0,95, coeficiente de correlação de validação não-cruzada, e q² = 0,80, coeficiente de correlação de validação cruzada), indicando a capacidade de predição do melhor modelo para novas moléculas. O modelo foi então utilizado para predizer valores das variáveis dependentes (pKi) de um conjunto teste de compostos, e os valores obtidos apresentaram boa concordância com os resultados experimentais. A integração de estudos de QSAR 3D, docagem molecular e dinâmica molecular forneceram informações úteis em relação às bases estruturais para a inibição seletiva da enzima alvo.

Human African trypanosomiasis, also known as sleeping sickness, is a major cause of death in Africa, and for which there are no safe and effective treatments available. The enzyme aldolase from Trypanosoma brucei is an attractive, validated target for drug development. A series of alkyl-glycolamido and alkyl-monoglycolate derivatives was studied employing a combination of drug design approaches. Three-dimensional quantitative structure-activity relationships (3D QSAR) models were generated using the comparative molecular field analysis (CoMFA). Significant results were obtained for the best QSAR model (r² = 0.95, non-cross-validated correlation coefficient, and q² = 0.80, cross-validated correlation coefficient), indicating its predictive ability for untested compounds. The model was then used to predict values of the dependent variables (pKi) of an external test set, and the predicted values were in good agreement with the experimental results. The integration of 3D QSAR, molecular docking and molecular dynamics simulations provided further insight into the structural basis for selective inhibition of the target enzyme.

In an article recently published in Química Nova, entitled "Chemistry Without Borders" ("Química Sem Fronteiras") [Pinto, A. C.; Zucco, C.; Galembeck, F.; Andrade, J. B.; Vieira, P. C. Quim. Nova 2012, 35, 2092], the authors highlighted the important aspects of science and technology with special emphasis on the field of Chemistry and its contributions toward a more prosperous Brazil of future. As a second step in that direction, this article extends the discussion of a key issue for the country in the framework of the chemistry community through the so called position papers in strategic areas. This document is a part of the contribution of the Brazilian Chemical Society to the World Science Forum to be held in Rio de Janeiro in November 2013. In this context, the present paper provides a brief discussion on neglected tropical diseases (NTDs) with emphasis on the current challenges and opportunities towards the development and evolution of the field. NTDs leads to illness, long-term disability or death, and has severe social, economic and psychological consequences for millions of men, women, and children worldwide. In most cases, the available treatments are inadequate and extremely limited in terms of efficacy and safety, leading to an urgent demand for new drugs. In addition to the traditional challenges involved in any drug discovery process, it is widely recognized that there is an innovation gap and a lack of investment for research and development (R&D) in the area of NTDs. In the last few decades, methods toward combating, eradication, prevention, and treatment of NTDs have been repeatedly emphasized in the major international agendas. Developments in these strategies and alliances have continued to have an essential impact, particularly in the area of drug discovery, both in Brazil and globally and should be encouraged and supported. Several examples of international activities dedicated to the reduction of the devastating global impact of NTDs can be provided. Despite the beneficial developments in the past 30 years, NTDs continue to devastate poor communities in remote and vulnerable areas, in large part, due to market failures and public policies. Recent studies have shown that among 756 new drugs approved between 2000 and 2011, only four new chemical entities (NCEs) were identified for the treatment of malaria, while none were developed against NTDs or tuberculosis. Furthermore, only 1.4% of approximately 150,000 clinical trials were registered for neglected diseases, with a smaller number of trials for NCEs. Establishment and strengthening of global strategies involving the triad "government-academia-industry" is fundamental to the success in R&D of new drugs for NTDs. National and international public-private initiatives that aim to create, encourage, and invest in R&D projects have been implemented and therefore are of utmost importance to successfully integrate Brazil into this new paradigm. It is essential to lay the foundation for mechanisms that will intensify investments in infrastructure, training, and qualification of personnel with an ultimate strategic vision that foresees continuity. Our research group has made significant contributions to the development of this field with the goal of forging new frontiers while tackling both current and future challenges that include indispensable elements such as innovation and integration.

A permeabilidade da barreira hematoencefálica (BBB, do inglês blood-brain barrier) é uma propriedade fundamental no planejamento de fármacos que atuam no sistema nervoso central (CNS) no tratamento de doenças como a epilepsia, depressão, mal de Alzheimer, mal de Parkinson, esquizofrenia, entre outras. No presente trabalho, estudos das relações quantitativas entre a estrutura e propriedade (QSPR) foram conduzidos para o desenvolvimento e validação de modelos in silico para a predição da permeabilidade da BBB. O conjunto de dados utilizado possui significativa diversidade química e ampla distribuição dos valores da propriedade alvo. Os modelos de QSPR gerados apresentaram bons parâmetros estatísticos e foram empregados com sucesso na predição de um conjunto teste de 48 compostos. Os modelos desenvolvidos são úteis na identificação, seleção e planejamento de candidatos a novos fármacos com propriedades farmacocinéticas otimizadas.

Blood-brain barrier (BBB) permeation is an essential property for drugs that act in the central nervous system (CNS) for the treatment of human diseases, such as epilepsy, depression, Alzheimer's disease, Parkinson disease, schizophrenia, among others. In the present work, quantitative structure-property relationship (QSPR) studies were conducted for the development and validation of in silico models for the prediction of BBB permeation. The data set used has substantial chemical diversity and a relatively wide distribution of property values. The generated QSPR models showed good statistical parameters and were successfully employed for the prediction of a test set containing 48 compounds. The predictive models presented herein are useful in the identification, selection and design of new drug candidates having improved pharmacokinetic properties.