Showing papers by "Elias Castanas published in 2021"

p-cymene impairs SARS-CoV-2 and Influenza A (H1N1) viral replication: In silico predicted interaction with SARS-CoV-2 nucleocapsid protein and H1N1 nucleoprotein.

Abstract: Therapeutic regimens for the COVID-19 pandemics remain unmet. In this line, repurposing of existing drugs against known or predicted SARS-CoV-2 protein actions have been advanced, while natural products have also been tested. Here, we propose that p-cymene, a natural monoterpene, can act as a potential novel agent for the treatment of SARS-CoV-2-induced COVID-19 and other RNA-virus-induced diseases (influenza, rabies, Ebola). We show by extensive molecular simulations that SARS-CoV-2 C-terminal structured domain contains a nuclear localization signal (NLS), like SARS-CoV, on which p-cymene binds with low micromolar affinity, impairing nuclear translocation of this protein and inhibiting viral replication, as verified by preliminary in vitro experiments. A similar mechanism may occur in other RNA-viruses (influenza, rabies and Ebola), also verified in vitro for influenza, by interaction of p-cymene with viral nucleoproteins, and structural modification of their NLS site, weakening its interaction with importin A. This common mechanism of action renders therefore p-cymene as a possible antiviral, alone, or in combination with other agents, in a broad spectrum of RNA viruses, from SARS-CoV-2 to influenza A infections.

Consumers' attitude toward dietary supplements and functional food: a prospective survey in a Greek population sample.

Abstract: The main objective of the present study was to investigate the attitudes among a sample of educated Greek consumers toward the use of dietary supplements (DS) and functional foods (FF) given that attitudes and behaviors as regards DS/FF have not been sufficiently evaluated in Southern Europe, where their penetration is lower as compared to northern countries. An online questionnaire was completed by 358 individuals (n = 358, 55.6% females, 44.4% males, and 82% of the total with higher education). Questionnaire reliability was assessed by Cronbach’s alpha coefficient while independence among qualitative variables was assayed by Pearson’s chi-squared test or Fisher’s exact test. The different groups of questions were analyzed by factor analysis, with principal component analysis and Varimax rotation, applied after a factor analysis and Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy test. Finally, a hierarchical cluster analysis based on Ward’s method, using the squared Euclidean distance as a measure, was performed in order to identify and classify cases. Our results revealed that the majority of responders were aware of the principles of healthy eating, considering DS/FF as valid additives conferring beneficial effects. A surprising finding is that consumers, independently of the use of DS/FF, tend to prepare food at home and to adhere strongly to the Mediterranean diet and its principles. In addition, they express a certain degree of wariness as to product labeling and health claims, following instead the recommendations of health professionals and scientific evidence. Finally, they prefer to purchase DS/FF from pharmacies. Our findings provide valuable data concerning active Greek consumers’ attitudes toward these relative new products, which could be extended to other Mediterranean and South European populations.

A mixture of essential oils from three Cretan Aromatic Plants (thyme, Greek sage and Cretan dittany, CAPeo) inhibits SASR-CoV-2 proliferation: in vitro evidence and a Proof-of-Concept intervention study in mild ambulatory COVID-19-positive patients

Abstract: The need for therapeutic regimens for the non-critically ill patients of the COVID-19 pandemic remains unmet. In this line, repurposing existing drugs, against known or predicted SARS-CoV-2 protein actions, has been advanced, while natural products have also been tested. Previous work has shown that a Cretan Aromatic Plant (Thymbra capitata (L.) Cav., Salvia fruticosa Mill. and Origanum dictamnus L.) essential oil mixture (CAPeo) has a remarkable in vitro antiviral activity against Influenza A & B and Rhinovirus 14 strains, decreasing the symptoms of upper respiratory tract infections, while proven safe in experimental animals and humans. Here, we tested CAPeo in VERO cells infected with SASR-CoV-2. We report that this mixture, at similar concentrations as those previously reported, exhibits a remarkable antiviral activity. Administration of 1 ml of a 1.5% CAPeo in olive oil, in a Proof-of-Concept intervention study in SARS-CoV-2-positive, exhibiting mild COVID-19 symptoms, humans resulted in a significant amelioration of general and local symptoms of the disease. We conclude that CAPeo may be a valuable addition for the prevention and/or treatment of mild COVID-19 ambulatory patients, pending a confirmation through a prospective randomized controlled trial in humans (NCT04705753).

Natural Polyphenols Inhibit the Dimerization of the SARS-CoV-2 Main Protease: The Case of Fortunellin and Its Structural Analogs.

Abstract: 3CL-Pro is the SARS-CoV-2 main protease (MPro). It acts as a homodimer to cleave the large polyprotein 1ab transcript into proteins that are necessary for viral growth and replication. 3CL-Pro has been one of the most studied SARS-CoV-2 proteins and a main target of therapeutics. A number of drug candidates have been reported, including natural products. Here, we employ elaborate computational methods to explore the dimerization of the 3CL-Pro protein, and we formulate a computational context to identify potential inhibitors of this process. We report that fortunellin (acacetin 7-O-neohesperidoside), a natural flavonoid O-glycoside, and its structural analogs are potent inhibitors of 3CL-Pro dimerization, inhibiting viral plaque formation in vitro. We thus propose a novel basis for the search of pharmaceuticals as well as dietary supplements in the fight against SARS-CoV-2 and COVID-19.

ERα36-GPER1 Collaboration Inhibits TLR4/NFκB-Induced Pro-Inflammatory Activity in Breast Cancer Cells.

Abstract: Inflammation is important for the initiation and progression of breast cancer. We have previously reported that in monocytes, estrogen regulates TLR4/NFκB-mediated inflammation via the interaction of the Erα isoform ERα36 with GPER1. We therefore investigated whether a similar mechanism is present in breast cancer epithelial cells, and the effect of ERα36 expression on the classic 66 kD ERα isoform (ERα66) functions. We report that estrogen inhibits LPS-induced NFκB activity and the expression of downstream molecules TNFα and IL-6. In the absence of ERα66, ERα36 and GPER1 are both indispensable for this effect. In the presence of ERα66, ERα36 or GPER1 knock-down partially inhibits NFκB-mediated inflammation. In both cases, ERα36 overexpression enhances the inhibitory effect of estrogen on inflammation. We also verify that ERα36 and GPER1 physically interact, especially after LPS treatment, and that GPER1 interacts directly with NFκB. When both ERα66 and ERα36 are expressed, the latter acts as an inhibitor of ERα66 via its binding to estrogen response elements. We also report that the activation of ERα36 leads to the inhibition of breast cancer cell proliferation. Our data support that ERα36 is an inhibitory estrogen receptor that, in collaboration with GPER1, inhibits NFκB-mediated inflammation and ERα66 actions in breast cancer cells.

New Antagonists of the Membrane Androgen Receptor OXER1 from the ZINC Natural Product Database.

Abstract: OXER1 (oxoeicosanoid receptor 1) was deorphanized in 1993 and found to be the specific receptor for the arachidonic acid metabolite 5-oxo-ETE. Recently, we have reported that androgen binds to this receptor also, being a membrane androgen receptor, triggering a number of its membrane-mediated actions (cell migration, apoptosis, cell proliferation, Ca2+ movements). In addition, our previous work suggested that a number of natural monomeric and oligomeric polyphenols interact with OXER1, acting similar to testosterone. Here, we interrogated the natural product chemical space and identified nine polyphenolic molecules with interesting in silico pharmacological activities as putative OXER1 antagonists. The molecule with the best pharmacokinetic-pharmacodynamic properties (ZINC15959779) was purchased and tested on OXER1, in prostate cancer cell cultures. It showed that it has actions similar to those of testosterone in inhibiting cAMP, while it had no action in intracellular Ca2+ mobilization or actin cytoskeleton rearrangement/migration. These results are discussed under the prism of structure-activity relationships and in silico models of the OXER1 binding groove. We suggest that these compounds, together with the previously reported (poly)phenolic compounds, can be lead structures for the exploration of the anti-inflammatory and antiproliferative effects of OXER1 antagonists.

Glycosylation Modulates Plasma Membrane Trafficking of CD24 in Breast Cancer Cells.

Abstract: In breast cancer, expression of Cluster of Differentiation 24 (CD24), a small GPI-anchored glycoprotein at the cell periphery, is associated with metastasis and immune escape, while its absence is associated with tumor-initiating capacity. Since the mechanism of CD24 sorting is unknown, we investigated the role of glycosylation in the subcellular localization of CD24. Expression and localization of wild type N36- and/or N52-mutated CD24 were analyzed using immunofluorescence in luminal (MCF-7) and basal B (MDA-MB-231 and Hs578T) breast cancer cells lines, as well as HEK293T cells. Endogenous and exogenously expressed wild type and mutated CD24 were found localized at the plasma membrane and the cytoplasm, but not the nucleoplasm. The cell lines showed different kinetics for the sorting of CD24 through the secretory/endocytic pathway. N-glycosylation, especially at N52, and its processing in the Golgi were critical for the sorting and expression of CD24 at the plasma membrane of HEK293T and basal B type cells, but not of MCF-7 cells. In conclusion, our study highlights the contribution of N-glycosylation for the subcellular localization of CD24. Aberrant N-glycosylation at N52 of CD24 could account for the lack of CD24 expression at the cell surface of basal B breast cancer cells.