Tamoxifen-like metallocifens target thioredoxin system determining mitochondrial impairment leading to apoptosis in Jurkat cells

Tamoxifen-like metallocifens (TLMs) of the group-8 metals (Fe, Ru, and Os) show strong anti-proliferative activity on cancer cell lines resistant to apoptosis, owing to their unique redox properties. In contrast, the thioredoxin system, which is involved in cellular redox balance, is often overexpressed in cancer cells, especially in tumour types resistant to standard chemotherapies. Therefore, we investigated the effect of these three TLMs on the thioredoxin system and evaluated the input of the metallocene unit in comparison with structurally related organic tamoxifens. In vitro, all three TLMs became strong inhibitors of the cytosolic (TrxR1) and mitochondrial (TrxR2) isoforms of thioredoxin reductase after enzymatic oxidation with HRP/H2O2 while none of the organic analogues was effective. In Jurkat cells, TLMs inhibited mainly TrxR2, resulting in the accumulation of oxidized thioredoxin 2 and cell redox imbalance. Overproduction of ROS resulted in a strong decrease in the mitochondrial membrane potential, translocation of cytochrome c to the cytosol and activation of caspase 3, thus leading to apoptosis. None of these events occurred with organic tamoxifens. The mitochondrial fraction of cells exposed to TLMs contained a high amount of the corresponding metal, as quantified by ICP-OES. The lipophilic and cationic character associated with the singular redox properties of the TLMs could explain why they alter the mitochondrial function. These results provide new insights into the mechanism of action of tamoxifen-like metallocifens, underlying their prodrug behaviour and the pivotal role played by the metallocenic entity in their cytotoxic activity associated with the induction of apoptosis

Organometallic compounds of osmium for cancer therapy

Cis-platin and its derivatives are the most currently used for cancer treatment. Inspired by these metallodrugs, organometallic compounds (Ti, Ru, Fe, Rh, Au…) have been developed over the years as potential candidates for anticancer drugs, some of these have entered clinical trials. Jaouen and co-workers have developed novel therapeutic agents based on ferrocene compounds analogous to tamoxifen, which show high anti-proliferative effects against two types of breast cancer cells, namely the ER+ breast carcinoma (MCF-7) and the ER- breast carcinoma (MDA-MB-231). Similarly, Leong’s group has found a series of triosmium carbonyl clusters that shows anticancer activity against these two breast cancer cells. Thus, it would be interesting to study osmocene compounds analogous to tamoxifen. Cytotoxic activity of these tamoxifen analogues, as well as that of triosmium clusters, were studied. This work aims to study the relationship between structure and activity of triosmium cluster Os3(CO)10(NCMe)2 compound with cytotoxic properties. The results show that the presence of a vacant coordination site and good solubility are important to have a good cytotoxic activity. The second part of the study was devoted to osmocene analogues (osmocifens), especially in the comparative study between the cytotoxic activity of three metallocene series: ferrocifen, ruthenocifen and osmocen. For osmium and ruthenium complexes, only compounds containing the amino chain are active while the phenolic compounds are almost inactive.DOCTOR OF PHILOSOPHY (SPMS

New mechanistic insights into osmium-based tamoxifen derivatives

International audienceThe electrochemical behavior of osmociphenol (3, Oc-OH), an organometallic osmium-based anticancer drug candidate, has been investigated by cyclic voltammetry in the absence and presence of lutidine used as a base model. Osmociphenol exhibited spontaneous deprotonation of the phenol function upon oxidation of the osmocene moiety due to its high acidity. In the presence of lutidine, a base-dependent and different electrochemical behavior was observed at low scan rates indicating a second oxidation step leading to the corresponding cationic quinone methide precursor (3b +). However, compared to ruthenocene derivatives, the stability of 3b + prevented its conversion into quinone methide as the final and stable complex. Despite differences in their oxidative processes, osmociphenol and ruthenociphenol derivatives exhibit similar biological activities

Synthesis, Characterization, and Biological Properties of Osmium-Based Tamoxifen Derivatives - Comparison with Their Homologues in the Iron and Ruthenium Series: Osmium-Based Tamoxifen Derivatives

International audienceno abstrac

Osmocenyl-tamoxifen derivatives target the thioredoxin system leading to a redox imbalance in Jurkat cells

The synthesis and the biological effects of two ferrocifen analogs in the osmium series, namely the monophenolic complex 1, the tamoxifen-like complex 2 and their oxidized quinone methide (QM) derivatives, 1-QM and 2-QM, are reported. Inhibition of purified thioredoxin reductase (TrxR) is observed with 1 and 2 only after their enzymatic oxidation by the hydrogen peroxide/horseradish peroxidase (H2O2/HRP) system with IC50 of 2.4 and 1.2\u3bcM respectively. However, this inhibition is larger than that obtained with the corresponding quinone methides (IC50=5.4\u3bcM for 1-QM and 3.6\u3bcM for 2-QM). The UV-Vis spectra of 1 or 2 incubated in the presence of H2O2/HRP show that the species generated is not a quinone methide, but probably the corresponding cation. In Jurkat cells, 2 shows high toxicity (IC50=7.4\u3bcM), while 1 is less effective (IC50=42\u3bcM). Interestingly, a significant inhibition of TrxR activity is observed in cells incubated with 2 (about 70% inhibition with 15\u3bcM) while the inhibition induced by 1 is much weaker (about 30% inhibition with 50\u3bcM). This strong inhibition of TrxR by 2 leads to accumulation of thioredoxin and peroxiredoxin 3 in oxidized form and to a decrease of the mitochondrial membrane potential (MMP). These results show that cytotoxicity of the osmocifens depends on their oxidation within the cell and that inhibition of thioredoxin reductase by oxidized species is a key factor in rationalizing the cytotoxicity of these complexes on Jurkat cells

Synchrotron Radiation X-Ray Fluorescence Nanoimaging Reveal the Intracellular Localization of Potent Anticancer Drug Osmocenyl-Tamoxifen Derivative

International audienc

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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Efficacy and safety of two neutralising monoclonal antibody therapies, sotrovimab and BRII-196 plus BRII-198, for adults hospitalised with COVID-19 (TICO): a randomised controlled trial

We aimed to assess the efficacy and safety of two neutralising monoclonal antibody therapies (sotrovimab [Vir Biotechnology and GlaxoSmithKline] and BRII-196 plus BRII-198 [Brii Biosciences]) for adults admitted to hospital for COVID-19 (hereafter referred to as hospitalised) with COVID-19. In this multinational, double-blind, randomised, placebo-controlled, clinical trial (Therapeutics for Inpatients with COVID-19 [TICO]), adults (aged ≥18 years) hospitalised with COVID-19 at 43 hospitals in the USA, Denmark, Switzerland, and Poland were recruited. Patients were eligible if they had laboratory-confirmed SARS-CoV-2 infection and COVID-19 symptoms for up to 12 days. Using a web-based application, participants were randomly assigned (2:1:2:1), stratified by trial site pharmacy, to sotrovimab 500 mg, matching placebo for sotrovimab, BRII-196 1000 mg plus BRII-198 1000 mg, or matching placebo for BRII-196 plus BRII-198, in addition to standard of care. Each study product was administered as a single dose given intravenously over 60 min. The concurrent placebo groups were pooled for analyses. The primary outcome was time to sustained clinical recovery, defined as discharge from the hospital to home and remaining at home for 14 consecutive days, up to day 90 after randomisation. Interim futility analyses were based on two seven-category ordinal outcome scales on day 5 that measured pulmonary status and extrapulmonary complications of COVID-19. The safety outcome was a composite of death, serious adverse events, incident organ failure, and serious coinfection up to day 90 after randomisation. Efficacy and safety outcomes were assessed in the modified intention-to-treat population, defined as all patients randomly assigned to treatment who started the study infusion. This study is registered with ClinicalTrials.gov, NCT04501978. Between Dec 16, 2020, and March 1, 2021, 546 patients were enrolled and randomly assigned to sotrovimab (n=184), BRII-196 plus BRII-198 (n=183), or placebo (n=179), of whom 536 received part or all of their assigned study drug (sotrovimab n=182, BRII-196 plus BRII-198 n=176, or placebo n=178; median age of 60 years [IQR 50–72], 228 [43%] patients were female and 308 [57%] were male). At this point, enrolment was halted on the basis of the interim futility analysis. At day 5, neither the sotrovimab group nor the BRII-196 plus BRII-198 group had significantly higher odds of more favourable outcomes than the placebo group on either the pulmonary scale (adjusted odds ratio sotrovimab 1·07 [95% CI 0·74–1·56]; BRII-196 plus BRII-198 0·98 [95% CI 0·67–1·43]) or the pulmonary-plus complications scale (sotrovimab 1·08 [0·74–1·58]; BRII-196 plus BRII-198 1·00 [0·68–1·46]). By day 90, sustained clinical recovery was seen in 151 (85%) patients in the placebo group compared with 160 (88%) in the sotrovimab group (adjusted rate ratio 1·12 [95% CI 0·91–1·37]) and 155 (88%) in the BRII-196 plus BRII-198 group (1·08 [0·88–1·32]). The composite safety outcome up to day 90 was met by 48 (27%) patients in the placebo group, 42 (23%) in the sotrovimab group, and 45 (26%) in the BRII-196 plus BRII-198 group. 13 (7%) patients in the placebo group, 14 (8%) in the sotrovimab group, and 15 (9%) in the BRII-196 plus BRII-198 group died up to day 90. Neither sotrovimab nor BRII-196 plus BRII-198 showed efficacy for improving clinical outcomes among adults hospitalised with COVID-19. US National Institutes of Health and Operation Warp Spee