Corrigendum: HSA-nanobinders crafted from bioresponsive prodrugs for combined cancer chemoimmunotherapy-an in vitro exploration.

[This corrects the article DOI: 10.3389/fchem.2024.1378233.].

The novel SMYD3 inhibitor EM127 impairs DNA repair response to chemotherapy-induced DNA damage and reverses cancer chemoresistance.

BACKGROUND: SMYD3 has been found implicated in cancer progression. Its overexpression correlates with cancer growth and invasion, especially in gastrointestinal tumors. SMYD3 transactivates multiple oncogenic mechanisms, favoring cancer development. Moreover, it was recently shown that SMYD3 is required for DNA restoration by promoting homologous recombination (HR) repair. METHODS: In cellulo and in vivo models were employed to investigate the role of SMYD3 in cancer chemoresistance. Analyses of SMYD3-KO cells, drug-resistant cancer cell lines, patients' residual gastric or rectal tumors that were resected after neoadjuvant therapy and mice models were performed. In addition, the novel SMYD3 covalent inhibitor EM127 was used to evaluate the impact of manipulating SMYD3 activity on the sensitization of cancer cell lines, tumorspheres and cancer murine models to chemotherapeutics (CHTs). RESULTS: Here we report that SMYD3 mediates cancer cell sensitivity to CHTs. Indeed, cancer cells lacking SMYD3 functions showed increased responsiveness to CHTs, while restoring its expression promoted chemoresistance. Specifically, SMYD3 is essential for the repair of CHT-induced double-strand breaks as it methylates the upstream sensor ATM and allows HR cascade propagation through CHK2 and p53 phosphorylation, thereby promoting cancer cell survival. SMYD3 inhibition with the novel compound EM127 showed a synergistic effect with CHTs in colorectal, gastric, and breast cancer cells, tumorspheres, and preclinical colorectal cancer models. CONCLUSIONS: Overall, our results show that targeting SMYD3 may be an effective therapeutic strategy to overcome chemoresistance.

HSA-nanobinders crafted from bioresponsive prodrugs for combined cancer chemoimmunotherapy-an in vitro exploration.

Introduction: Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer still lacking effective treatment options. Chemotherapy in combination with immunotherapy can restrict tumor progression and repolarize the tumor microenvironment towards an anti-tumor milieu, improving clinical outcome in TNBC patients. The chemotherapeutic drug paclitaxel has been shown to induce immunogenic cell death (ICD), whereas inhibitors of the indoleamine 2,3- dioxygenase 1 (IDO1) enzyme, whose expression is shared in immune regulatory and tumor cells, have been revealed to enhance the anti-tumor immune response. However, poor bioavailability and pharmacokinetics, off-target effects and hurdles in achieving therapeutic drug concentrations at the target tissue often limit the effectiveness of combination therapies. Methods: This work describes the development of novel biomimetic and carrier-free nanobinders (NBs) loaded with both paclitaxel and the IDO1 inhibitor NLG919 in the form of bioresponsive and biomimetic prodrugs. A fine tuning of the preparation conditions allowed to identify NB@5 as the most suitable nanoformulation in terms of reproducibility, stability and in vitro effectiveness. Results and discussion: Our data show that NB@5 effectively binds to HSA in cell-free experiments, demonstrating its protective role in the controlled release of drugs and suggesting the potential to exploit the protein as the endogenous vehicle for targeted delivery to the tumor site. Our study successfully proves that the drugs encapsulated within the NBs are preferentially released under the altered redox conditions commonly found in the tumor microenvironment, thereby inducing cell death, promoting ICD, and inhibiting IDO1.

Association between Albumin Alterations and Renal Function in Patients with Type 2 Diabetes Mellitus.

Diabetic kidney disease (DKD) is a major cause of morbidity and mortality in individuals with type 2 diabetes mellitus (T2DM). The aim of this study was to investigate whether albumin structural alterations correlate with DKD severity and evaluate whether native and reduced albumin concentrations could complement the diagnosis of DKD. To this end, one hundred and seventeen T2DM patients without (n = 42) and with (n = 75) DKD (DKD I-III upon KDIGO classification) were evaluated; the total albumin concentration (tHA) was quantified by a bromocresol green assay, while structural alterations were profiled via liquid chromatography-high-resolution mass spectrometry (LC-HRMS). The concentrations of native albumin (eHA, effective albumin) and reduced albumin (rHA) were subsequently assessed. The HRMS analyses revealed a reduced relative amount of native albumin in DKD patients along with an increased abundance of altered forms, especially those bearing oxidative modifications. Accordingly, both eHA and rHA values varied during the stages of progressive renal failure, and these alterations were dose-dependently correlated with renal dysfunction. A ROC curve analysis revealed a significantly greater sensitivity and specificity of eHA and rHA than of tHA for diagnosing DKD. Importantly, according to the multivariate logistic regression analysis, the eHA was identified as an independent predictor of DKD.

Quinolinetrione-tacrine hybrids as multi-target-directed ligands against Alzheimer's disease.

Multi-target drug discovery is one of the most active fields in the search for new drugs against Alzheimer's disease (AD). This is because the complexity of AD pathological network might be adequately tackled by multi-target-directed ligands (MTDLs) aimed at modulating simultaneously multiple targets of such a network. In a continuation of our efforts to develop MTDLs for AD, we have been focusing on the molecular hybridization of the acetylcholinesterase inhibitor tacrine with the aim of expanding its anti-AD profile. Herein, we manipulated the structure of a previously developed tacrine-quinone hybrid (1). We designed and synthesized a novel set of MTDLs (2-6) by replacing the naphthoquinone scaffold of 1 with that of 2,5,8-quinolinetrione. The most interesting hybrid 3 inhibited cholinesterase enzymes at nanomolar concentrations. In addition, 3 exerted antioxidant effects in menadione-induced oxidative stress of SH-SY5Y cells. Importantly, 3 also showed low hepatotoxicity and good anti-amyloid aggregation properties. Remarkably, we uncovered the potential of the quinolinetrione scaffold, as a novel anti-amyloid aggregation and antioxidant motif to be used in further anti-AD MTDL drug discovery endeavors.

Role of D(-)-Lactic Acid in Prevention of Chlamydia trachomatis Infection in an In Vitro Model of HeLa Cells.

A vaginal microbiota dominated by certain Lactobacillus species may have a protective effect against Chlamydia trachomatis infection. One of the key antimicrobial compounds produced is lactic acid, which is believed to play a central role in host defense. Lactobacillus strains producing the D(-)-lactic acid isomer are known to exert stronger protection. However, the molecular mechanisms underlying this antimicrobial action are not well understood. The aim of this study was to investigate the role of D(-)-lactic acid isomer in the prevention of C. trachomatis infection in an in vitro HeLa cell model. We selected two strains of lactobacilli belonging to different species: a vaginal isolate of Lactobacillus crispatus that releases both D(-) and L(+) isomers and a strain of Lactobacillus reuteri that produces only the L(+) isomer. Initially, we demonstrated that L. crispatus was significantly more effective than L. reuteri in reducing C. trachomatis infectivity. A different pattern of histone acetylation and lactylation was observed when HeLa cells were pretreated for 24 h with supernatants of Lactobacillus crispatus or L. reuteri, resulting in different transcription of genes such as CCND1, CDKN1A, ITAG5 and HER-1. Similarly, distinct transcription patterns were found in HeLa cells treated with 10 mM D(-)- or L(+)-lactic acid isomers. Our findings suggest that D(-) lactic acid significantly affects two non-exclusive mechanisms involved in C. trachomatis infection: regulation of the cell cycle and expression of EGFR and α5ß1-integrin.

Exopolysaccharides from vaginal lactobacilli modulate microbial biofilms.

BACKGROUND: Exopolysaccharides (EPS) secreted by beneficial lactobacilli exert a plethora of positive activities, but little is known about their effects on biofilms of opportunistic vaginal pathogens and especially on biofilms of lactobacilli themselves. Here, the EPS produced by six vaginal lactobacilli, belonging to Lactobacillus crispatus (BC1, BC4, BC5) and Lactobacillus gasseri (BC9, BC12, BC14) species were isolated from cultural supernatants and lyophilized. RESULTS: Lactobacillus EPS were chemically characterized in terms of monosaccharide composition by liquid chromatography (LC) analysis coupled to UV and mass spectrometry (MS) detection. Moreover, the ability of EPS (0.1, 0.5, 1 mg/mL) to stimulate the biofilm formation of lactobacilli and to inhibit the formation of pathogens' biofilms was evaluated by crystal violet (CV) staining and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Isolated EPS (yields 133-426 mg/L) were heteropolysaccharides mainly composed of D-mannose (40-52%) and D-glucose (11-30%). For the first time we demonstrated that Lactobacillus EPS were able to stimulate in a dose-dependent manner (p < 0.05) the formation of biofilms of ten strains belonging to L. crispatus, L. gasseri and Limosilactobacillus vaginalis species, in terms of cell viability (84-282% increase at 1 mg/mL) and especially biofilm biomass (40-195% increase at 1 mg/mL), quantified with MTT assay and CV staining, respectively. EPS released from L. crispatus and L. gasseri were found to better stimulate the biofilms of the same producer species rather than that of other species, including producing strains themselves and other strains. Conversely, the biofilm formation of bacterial (Escherichia coli, Staphylococcus spp., Enterococcus spp. and Streptococcus agalactiae) and fungal (Candida spp.) pathogens was inhibited. The anti-biofilm activity was dose-dependent and was more marked for L. gasseri-derived EPS (inhibition up to 86%, 70%, and 58% at 1 mg/mL, 0.5 mg/mL, and 0.1 mg/mL, respectively), whilst L. crispatus-derived EPS resulted overall less efficient (inhibition up to 58% at 1 mg/mL and 40% at 0.5 mg/mL) (p < 0.05). CONCLUSIONS: Lactobacilli-derived EPS favour the biofilm formation of lactobacilli preventing, at the same time, that of opportunistic pathogens. These results support the possible employment of EPS as postbiotics in medicine as a therapeutic/preventive strategy to counteract vaginal infections.

Inhibition of ß-Amyloid Aggregation in Alzheimer's Disease: The Key Role of (Pro)electrophilic Warheads.

Catechols have been largely investigated as antiaggregating agents toward ß-amyloid peptide. Herein, as a follow up of a previous series of hydroxycinnamic derivatives, we synthesized a small set of dihydroxy isomers for exploring the role of the reciprocal position of the two hydroxyl functions at a molecular level. Para- and ortho-derivatives effectively reduced amyloid fibrillization, while the meta-analogue was devoid of any activity in this respect. Electrochemical analyses showed that the antiaggregating potency correlates with the oxidation potential, hence indicating the proelectrophilic character as a prerequisite for activity. Interestingly, mass spectrometry studies and quantum mechanical calculations revealed different modes of action for active para- and ortho-derivatives, involving covalent or noncovalent interactions with ß-amyloid. The distinctive mode of action is also translated into a different cytotoxicity profile. This work clearly shows how apparently minimal structural modifications can completely change the compound behavior and generate alternative mechanisms of action of proelectrophilic chemical probes.

Discovery of the 4-aminopiperidine-based compound EM127 for the site-specific covalent inhibition of SMYD3.

Recent findings support the hypothesis that inhibition of SMYD3 methyltransferase may be a therapeutic avenue for some of the deadliest cancer types. Herein, active site-selective covalent SMYD3 inhibitors were designed by introducing an appropriate reactive cysteine trap into reversible first-generation SMYD3 inhibitors. The 4-aminopiperidine derivative EM127 (11C) bearing a 2-chloroethanoyl group as reactive warhead showed selectivity for Cys186, located in the substrate/histone binding pocket. Selectivity towards Cys186 was retained even at high inhibitor/enzyme ratio, as shown by mass spectrometry. The mode of interaction with the SMYD3 substrate/histone binding pocket was revealed by crystallographic studies. In enzymatic assays, 11C showed a stronger SMYD3 inhibitory effect compared to the reference inhibitor EPZ031686. Remarkably, 11C attenuated the proliferation of MDA-MB-231 breast cancer cell line at the same low micromolar range of concentrations that reduced SMYD3 mediated ERK signaling in HCT116 colorectal cancer and MDA-MB-231 breast cancer cells. Furthermore, 11C (5 µM) strongly decreased the steady-state mRNA levels of genes important for tumor biology such as cyclin dependent kinase 2, c-MET, N-cadherin and fibronectin 1, all known to be regulated, at least in part, by SMYD3. Thus, 11C is as a first example of second generation SMYD3 inhibitors; this agent represents a covalent and a site specific SMYD3 binder capable of potent and prolonged attenuation of methyltransferase activity.

Climate change effects on bread wheat phenology and grain quality: A case study in the north of Italy.

Increasing temperatures, heat waves, and reduction of annual precipitation are all the expressions of climate change (CC), strongly affecting bread wheat (Triticum aestivum L.) grain yield in Southern Europe. Being temperature the major driving force of plants' phenological development, these variations also have effects on wheat phenology, with possible consequences on grain quality, and gluten protein accumulation. Here, through a case study in the Bolognese Plain (North of Italy), we assessed the effects of CC in the area, the impacts on bread wheat phenological development, and the consequences on grain gluten quality. The increasing trend in mean annual air temperature in the area since 1952 was significant, with a breakpoint identified in 1989, rising from 12.7 to 14.1°C, accompanied by the signals of increasing aridity, i.e., increase in water table depth. Bread wheat phenological development was compared in two 15-year periods before and after the breakpoint, i.e., 1952-1966 (past period), and 2006-2020 (present period), the latest characterized by aridity and increased temperatures. A significant shortening of the chronological time necessary to reach the main phenological phases was observed for the present period compared to the past period, finally shortening the whole life cycle. This reduction, as well as the higher temperature regime, affected gluten accumulation during the grain-filling process, as emerged analyzing gluten composition in grain samples of the same variety harvested in the area both before and after the breakpoint in temperature. In particular, the proportion of gluten polymers (i.e., gliadins, high and low molecular weight glutenins, and their ratio) showed a strong and significant correlation with cumulative growing degree days (CGDDs) accumulated during the grain filling. Higher CGDD values during the period, typical of CC in Southern Europe, accounting for higher temperature and faster grain filling, correlated with gliadins, high molecular weight glutenins, and their proportion with low molecular weight glutenins. In summary, herein reported, data might contribute to assessing the effects of CC on wheat phenology and quality, representing a tool for both predictive purposes and decision supporting systems for farmers, as well as can guide future breeding choices for varietal innovation.

Discovery and In Vivo Proof of Concept of a Highly Potent Dual Inhibitor of Soluble Epoxide Hydrolase and Acetylcholinesterase for the Treatment of Alzheimer's Disease.

With innumerable clinical failures of target-specific drug candidates for multifactorial diseases, such as Alzheimer's disease (AD), which remains inefficiently treated, the advent of multitarget drug discovery has brought a new breath of hope. Here, we disclose a class of 6-chlorotacrine (huprine)-TPPU hybrids as dual inhibitors of the enzymes soluble epoxide hydrolase (sEH) and acetylcholinesterase (AChE), a multitarget profile to provide cumulative effects against neuroinflammation and memory impairment. Computational studies confirmed the gorge-wide occupancy of both enzymes, from the main site to a secondary site, including a so far non-described AChE cryptic pocket. The lead compound displayed in vitro dual nanomolar potencies, adequate brain permeability, aqueous solubility, human microsomal stability, lack of neurotoxicity, and it rescued memory, synaptic plasticity, and neuroinflammation in an AD mouse model, after low dose chronic oral administration.

HSA-Binding Prodrugs-Based Nanoparticles Endowed with Chemo and Photo-Toxicity against Breast Cancer.

Exploiting the tumor environment features (EPR effect, elevated glutathione, reactive oxygen species levels) might allow attaining a selective and responsive carrier capable of improving the therapeutic outcome. To this purpose, the in situ covalent binding of drugs and nanoparticles to circulating human serum albumin (HSA) might represent a pioneering approach to achieve an effective strategy. This study describes the synthesis, in vitro and in vivo evaluation of bioresponsive HSA-binding nanoparticles (MAL-PTX2S@Pba), co-delivering two different paclitaxel (PTX) prodrugs and the photosensitizer pheophorbide a (Pba), for the combined photo- and chemo-treatment of breast cancer. Stable and reproducible MAL-PTX2S@Pba nanoparticles with an average diameter of 82 nm and a PTX/Pba molar ratio of 2.5 were obtained by nanoprecipitation. The in vitro 2D combination experiments revealed that MAL-PTX2S@Pba treatment induces a strong inhibition of cell viability of MDA-MB-231, MCF7 and 4T1 cell lines, whereas 3D experiments displayed different trends: while MAL-PTX2S@Pba effectiveness was confirmed against MDA-MB-231 spheroids, the 4T1 model exhibited marked resistance. Lastly, despite using a low PTX-PDT regimen (e.g., 8.16 mg/Kg PTX and 2.34 mg/Kg Pba), our formulation showed to foster primary tumor reduction and curb lung metastases growth in 4T1 tumor-bearing mice, thus setting the basis for further preclinical validations.

Discovery of sustainable drugs for Alzheimer's disease: cardanol-derived cholinesterase inhibitors with antioxidant and anti-amyloid properties.

As part of our efforts to develop sustainable drugs for Alzheimer's disease (AD), we have been focusing on the inexpensive and largely available cashew nut shell liquid (CNSL) as a starting material for the identification of new acetylcholinesterase (AChE) inhibitors. Herein, we decided to investigate whether cardanol, a phenolic CNSL component, could serve as a scaffold for improved compounds with concomitant anti-amyloid and antioxidant activities. Ten new derivatives, carrying the intact phenolic function and an aminomethyl functionality, were synthesized and first tested for their inhibitory potencies towards AChE and butyrylcholinesterase (BChE). 5 and 11 were found to inhibit human BChE at a single-digit micromolar concentration. Transmission electron microscopy revealed the potential of five derivatives to modulate Aß aggregation, including 5 and 11. In HORAC assays, 5 and 11 performed similarly to standard antioxidant ferulic acid as hydroxyl scavenging agents. Furthermore, in in vitro studies in neuronal cell cultures, 5 and 11 were found to effectively inhibit reactive oxygen species production at a 10 µM concentration. They also showed a favorable initial ADME/Tox profile. Overall, these results suggest that CNSL is a promising raw material for the development of potential disease-modifying treatments for AD.

From virtual screening hits targeting a cryptic pocket in BACE-1 to a nontoxic brain permeable multitarget anti-Alzheimer lead with disease-modifying and cognition-enhancing effects.

Starting from six potential hits identified in a virtual screening campaign directed to a cryptic pocket of BACE-1, at the edge of the catalytic cleft, we have synthesized and evaluated six hybrid compounds, designed to simultaneously reach BACE-1 secondary and catalytic sites and to exert additional activities of interest for Alzheimer's disease (AD). We have identified a lead compound with potent in vitro activity towards human BACE-1 and cholinesterases, moderate Aß42 and tau antiaggregating activity, and brain permeability, which is nontoxic in neuronal cells and zebrafish embryos at concentrations above those required for the in vitro activities. This compound completely restored short- and long-term memory in a mouse model of AD (SAMP8) relative to healthy control strain SAMR1, shifted APP processing towards the non-amyloidogenic pathway, reduced tau phosphorylation, and increased the levels of synaptic proteins PSD95 and synaptophysin, thereby emerging as a promising disease-modifying, cognition-enhancing anti-AD lead.

Bio-Guided Fractionation of Stem Bark Extracts from Phyllanthus muellarianus: Identification of Phytocomponents with Anti-Cholinesterase Activity.

A combination of flash chromatography, solid phase extraction, high-performance liquid chromatography, and in vitro bioassays was used to isolate phytocomponents endowed with anticholinesterase activity in extract from Phyllanthus muellarianus. Phytocomponents responsible for the anti-cholinesterase activity of subfractions PMF1 and PMF4 were identified and re-assayed to confirm their activity. Magnoflorine was identified as an active phytocomponent from PMF1 while nitidine was isolated from PMF4. Magnoflorine was shown to be a selective inhibitor of human butyrylcholinesterase-hBChE (IC50 = 131 ± 9 µM and IC50 = 1120 ± 83 µM, for hBuChE and human acetylcholinesterase-hAChE, respectively), while nitidine showed comparable inhibitory potencies against both enzymes (IC50 = 6.68 ± 0.13 µM and IC50 = 5.31 ± 0.50 µM, for hBChE and hAChE, respectively). When compared with the commercial anti-Alzheimer drug galanthamine, nitidine was as potent as galanthamine against hAChE and one order of magnitude more potent against hBuChE. Furthermore, nitidine also showed significant, although weak, antiaggregating activity towards amyloid-ß self-aggregation.

New Coumarin Derivatives as Cholinergic and Cannabinoid System Modulators.

In the last years, the connection between the endocannabinoid system (eCS) and neuroprotection has been discovered, and evidence indicates that eCS signaling is involved in the regulation of cognitive processes and in the pathophysiology of Alzheimer's disease (AD). Accordingly, pharmacotherapy targeting eCS could represent a valuable contribution in fighting a multifaceted disease such as AD, opening a new perspective for the development of active agents with multitarget potential. In this paper, a series of coumarin-based carbamic and amide derivatives were designed and synthesized as multipotent compounds acting on cholinergic system and eCS-related targets. Indeed, they were tested with appropriate enzymatic assays on acetyl and butyryl-cholinesterases and on fatty acid amide hydrolase (FAAH), and also evaluated as cannabinoid receptor (CB1 and CB2) ligands. Moreover, their ability to reduce the self-aggregation of beta amyloid protein (Aß42) was assessed. Compounds 2 and 3, bearing a carbamate function, emerged as promising inhibitors of hAChE, hBuChE, FAAH and Aß42 self-aggregation, albeit with moderate potencies, while the amide 6 also appears a promising CB1/CB2 receptors ligand. These data prove for the new compounds an encouraging multitarget profile, deserving further evaluation.

Determination of Effective Albumin in Patients With Decompensated Cirrhosis: Clinical and Prognostic Implications.

BACKGROUND AND AIMS: Circulating albumin in cirrhosis can be dysfunctional because of accumulating structural damages, leading to the concept of effective albumin concentration (eAlb), referring to the albumin portion presenting structural and functional integrity. We aimed to estimate eAlb in patients with decompensated cirrhosis and analyze its relationships with albumin function and clinical outcomes as compared to total albumin concentration (tAlb). APPROACH AND RESULTS: We evaluated 319 patients with cirrhosis hospitalized for acute decompensation (AD) with and without acute-on-chronic liver failure (ACLF) and 18 age- and sex-comparable outpatients with compensated cirrhosis. tAlb was quantified by standard assay, whereas eAlb was estimated combining liquid chromatography/electrospray ionization/mass spectrometry and standard methods. Albumin binding and detoxification efficiency were evaluated by electron paramagnetic resonance analysis. Circulating albumin in patients with decompensated cirrhosis displayed multiple structural abnormalities, with reversible oxidation and glycation being the most frequent. As a result, eAlb progressively declined with the worsening of cirrhosis and was superior to tAlb in stratifying patients between compensated cirrhosis, AD, and ACLF, as well as patients with and without complications. Moreover, eAlb, but not tAlb, was closely associated with binding capacities in ACLF. Finally, eAlb at admission predicted the occurrence of ACLF within 30 days and mortality at 90 days better than tAlb. CONCLUSIONS: This large, observational study provides the evidence in patients with decompensated cirrhosis that eAlb can be quantified and differentiated from tAlb routinely measured in clinical practice. As compared to tAlb, eAlb is more closely associated with disease severity and albumin dysfunction and carries a greater prognostic power. These results prompt future research assessing eAlb as a biomarker for predicting prognosis and treatment response.

From Combinations to Single-Molecule Polypharmacology-Cromolyn-Ibuprofen Conjugates for Alzheimer's Disease.

Despite Alzheimer's disease (AD) incidence being projected to increase worldwide, the drugs currently on the market can only mitigate symptoms. Considering the failures of the classical paradigm "one target-one drug-one disease" in delivering effective medications for AD, polypharmacology appears to be a most viable therapeutic strategy. Polypharmacology can involve combinations of multiple drugs and/or single chemical entities modulating multiple targets. Taking inspiration from an ongoing clinical trial, this work aims to convert a promising cromolyn-ibuprofen drug combination into single-molecule "codrugs." Such codrugs should be able to similarly modulate neuroinflammatory and amyloid pathways, while showing peculiar pros and cons. By exploiting a linking strategy, we designed and synthesized a small set of cromolyn-ibuprofen conjugates (4-6). Preliminary plasma stability and neurotoxicity assays allowed us to select diamide 5 and ethanolamide 6 as promising compounds for further studies. We investigated their immunomodulatory profile in immortalized microglia cells, in vitro anti-aggregating activity towards Aß42-amyloid self-aggregation, and their cellular neuroprotective effect against Aß42-induced neurotoxicity. The fact that 6 effectively reduced Aß-induced neuronal death, prompted its investigation into an in vivo model. Notably, 6 was demonstrated to significantly increase the longevity of Aß42-expressing Drosophila and to improve fly locomotor performance.

Discovery of an Allosteric Ligand Binding Site in SMYD3 Lysine Methyltransferase.

SMYD3 is a multifunctional epigenetic enzyme with lysine methyltransferase activity and various interaction partners. It is implicated in the pathophysiology of cancers but with an unclear mechanism. To discover tool compounds for clarifying its biochemistry and potential as a therapeutic target, a set of drug-like compounds was screened in a biosensor-based competition assay. Diperodon was identified as an allosteric ligand; its R and S enantiomers were isolated, and their affinities to SMYD3 were determined (KD =42 and 84 µM, respectively). Co-crystallization revealed that both enantiomers bind to a previously unidentified allosteric site in the C-terminal protein binding domain, consistent with its weak inhibitory effect. No competition between diperodon and HSP90 (a known SMYD3 interaction partner) was observed although SMYD3-HSP90 binding was confirmed (KD =13 µM). Diperodon clearly represents a novel starting point for the design of tool compounds interacting with a druggable allosteric site, suitable for the exploration of noncatalytic SMYD3 functions and therapeutics with new mechanisms of action.

Indole Derivative Interacts with Estrogen Receptor Beta and Inhibits Human Ovarian Cancer Cell Growth.

Ovarian cancer remains the leading cause of mortality among gynecological tumors. Estrogen receptor beta (ERß) expression has been suggested to act as a tumor suppressor in epithelial ovarian cancer by reducing both tumor growth and metastasis. ERß expression abnormalities represent a critical step in the development and progression of ovarian cancer: for these reasons, its re-expression by genetic engineering, as well as the use of targeted ERß therapies, still constitute an important therapeutic approach. 3-{[2-chloro-1-(4-chlorobenzyl)-5-methoxy-6-methyl-1H-indol-3-yl]methylene}-5-hydroxy-6-methyl-1,3-dihydro-2H-indol-2-one, referred to here as compound 3, has been shown to have cytostatic as well cytotoxic effects on various hormone-dependent cancer cell lines. However, the mechanism of its anti-carcinogenic activity is not well understood. Here, we offer a possible explanation of such an effect in the human ovarian cancer cell line IGROV1. Chromatin binding protein assay and liquid chromatography mass spectrometry were exploited to localize and quantify compound 3 in cells. Molecular docking was used to prove compound 3 binding to ERß. Mass spectrometry-based approaches were used to analyze histone post-translational modifications. Finally, gene expression analyses revealed a set of genes regulated by the ERß/3 complex, namely CCND1, MYC, CDKN2A, and ESR2, providing possible molecular mechanisms that underline the observed antiproliferative effects.