Systematic screening of synthetic organochalcogen compounds with anticancer activity using human lung adenocarcinoma spheroids

Lung adenocarcinoma stands as a leading global cause of cancer-related fatalities, with current therapeutic approaches remaining unsatisfactory. Given the association between elevated oxidative markers and the aggressive nature of cancer cells (including multidrug resistance and metastatic potential) that can predict poor outcome of lung adenocarcinoma patients, any compounds that interfere with their aberrant redox biology should be rationally explored as innovative intervention strategies. This study was designed to screen potential anticancer activities within nine newly synthesized organochalcogen - compounds characterized by the presence of oxygen, sulfur, or selenium elements in their structure and exhibiting antioxidant activity - and systematically evaluated their performance against cisplatin, the cornerstone therapeutic agent for lung adenocarcinoma. Our methodology involved the establishment of optimal conditions for generating single tumor spheroids using A549 human lung adenocarcinoma cell line. The initiation interval for spheroid formation was determined to be four days in vitro (DIV), and these single spheroids demonstrated sustained growth over a period of 20 DIV. Toxic dose-response curves were subsequently performed for each compound after 24 and 48 h of incubation at the 12th DIV. Our findings reveal that at least two of the synthetic organochalcogen compounds exhibited noteworthy anticancer activity, surpassing cisplatin in key parameters such as lower LD (Lethal Dose) 50, larger drug activity area, and maximum amplitude of effect, and are promising drugs for futures studies in the treatment of lung adenocarcinomas. Physicochemical descriptors and prediction ADME (absorption, distribution, metabolism, and excretion) parameters of selected compounds were obtained using SwissADME computational tool; Molinspiration server was used to calculate a biological activity score, and possible molecule targets were evaluated by prediction with the SwissTargetPrediction server. This research not only sheds light on novel avenues for therapeutic exploration but also underscores the potential of synthetic organochalcogen compounds as agents with superior efficacy compared to established treatments.

Metabolic rewiring in melanoma drug-resistant cells

Several evidences indicate that melanoma, one of the deadliest types of cancer, presents the ability to transiently shift its phenotype under treatment or microenvironmental pressure to an invasive and treatment-resistant phenotype, which is characterized by cells with slow division cycle (also called slow-cycling cells) and high-OXPHOS metabolism. Many cellular marks have been proposed to track this phenotype, such as the expression levels of the master regulator of melanocyte differentiation (MITF) and the epigenetic factor JARID1B. It seems that the slow-cycling phenotype does not necessarily present a single gene expression signature. However, many lines of evidence lead to a common metabolic rewiring process in resistant cells that activates mitochondrial metabolism and changes the mitochondrial network morphology. Here, we propose that mitochondria-targeted drugs could increase not only the efficiency of target therapy, bypassing the dynamics between fast-cycling and slow-cycling, but also the sensitivity to immunotherapy by modulation of the melanoma microenvironment.

Cannabinoid-Based Therapies and Brain Development: Potential Harmful Effect of Early Modulation of the Endocannabinoid System

The endocannabinoid retrograde signaling pathway is widely expressed in the central nervous system, where it plays major roles in regulating synaptic plasticity (excitatory and inhibitory) through long-term potentiation and long-term depression. The endocannabinoid system (ECS) components-cannabinoid receptors, endocannabinoids and synthesis/degradation enzymes-are expressed and are functional from early developmental stages and throughout adolescent cortical development, regulating progenitor cell fate, neural differentiation, migration and survival. This may potentially confer increased vulnerability to adverse outcomes from early cannabinoid exposure. Cannabidiol (CBD) is one of the most studied exogenous cannabinoids, and CBD-enriched Cannabis extracts have been widely (and successfully) used as adjuvants to treat children with refractory epilepsy, and there is even a Food and Drug Administration (FDA)-approved drug with purified CBD derived from Cannabis. However, there is insufficient information on possible long-term changes in the central nervous system caused by cannabinoid treatments during early childhood. Like the majority of cannabinoids, CBD is able to exert its effects directly and indirectly through the ECS, which can perturb the regulatory processes mediated by this system. In addition, CBD has a large number of non-endocannabinoid targets, which can explain CBD's effects. Here, we review the current knowledge about CBD-based therapies-pure and CBD-enriched Cannabis extracts-in studies with pediatric patients, their side effects, and their mechanisms of action regarding the central nervous system and neurodevelopment aspects. Since Cannabis extracts contain Δ⁹-tetrahydrocannabinol (Δ⁹-THC), we consider that pure CBD is possibly safer for young patients. Nevertheless, CBD, as well as other natural and/or synthetic cannabinoids, should be studied in more detail as a therapeutic alternative to CBD-enriched Cannabis extracts for young patients.

Immunosenescence Induced by Plasma from Individuals with Obesity Caused Cell Signaling Dysfunction and Inflammation

OBJECTIVE

To evaluate the consequences of plasma from individuals with obesity on parameters associated with immunosenescence in unrelated healthy peripheral blood mononuclear cells (PBMC).

METHODS

Freshly isolated PBMC were incubated in media supplemented with 10% of plasma from individuals with obesity or control subjects for the first 4 hours of 24 to 120 hours of culture.

RESULTS

Plasma from individuals with obesity modulated the phenotype of healthy PBMC, leading to a higher rate of apoptosis, lower amounts of phospho-γH2AX and -p53, and mitochondrial dysfunction. After 120 hours, there was a higher secretion of inflammatory cytokines IL-1β and IL-8. CD8⁺ T lymphocytes presented decreased expression of CD28, which is associated with the immunosenescent phenotype. CD14⁺ macrophages showed increased expression of CD80 and CD206, suggesting a modulation in the activation of macrophages.

CONCLUSIONS

These results demonstrate that chronic systemic inflammation observed in obesity induces dysfunctional features in PBMC that are consistent with premature immunosenescence.

Mimicking Parkinson's Disease in a Dish: Merits and Pitfalls of the Most Commonly used Dopaminergic In Vitro Models

Parkinson's disease (PD) is the second most common neurodegenerative disorder and has both unknown etiology and non-curative therapeutic options. Patients begin to present the classic motor symptoms of PD-tremor at rest, bradykinesia and rigidity-once 50-70% of the dopaminergic neurons of the nigrostriatal pathway have degenerated. As a consequence of this, it is difficult to investigate the early-stage events of disease pathogenesis. In vitro experimental models are used extensively in PD research because they present a controlled environment that enables the direct investigation of the early molecular mechanisms that are potentially involved with dopaminergic degeneration, as well as for the screening of potential therapeutic drugs. However, the establishment of PD in vitro models is a controversial issue for neuroscience research not only because it is challenging to mimic, in isolated cell systems, the physiological neuronal environment, but also the pathophysiological conditions experienced by human dopaminergic cells in vivo during the progression of the disease. Since no previous work has attempted to systematically review the literature regarding the establishment of an optimal in vitro model, and/or the features presented by available models used in the PD field, this review aims to summarize the merits and limitations of the most widely used dopaminergic in vitro models in PD research, which may help the PD researcher to choose the most appropriate model for studies directed at the elucidation of the early-stage molecular events underlying PD onset and progression.

Phenylalanine induces oxidative stress and decreases the viability of rat astrocytes: possible relevance for the pathophysiology of neurodegeneration in phenylketonuria

The aim of this study was to investigate the effects of phenylalanine on oxidative stress and some metabolic parameters in astrocyte cultures from newborn Wistar rats. Astrocytes were cultured under four conditions: control (0.4 mM phenylalanine concentration in the Dulbecco's Modified Eagle Medium (DMEM) solution), Phe addition to achieve 0.5, 1.0 or 1.5 mM final phenylalanine concentrations. After 72 h the astrocytes were separated for the biochemical measurements. Overall measure of mitochondrial function by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and cell viability measured by lactate dehydrogenase (LDH) assays indicated that phenylalanine induced cell damage at the three concentrations tested. The alteration on the various parameters of oxidative stress indicated that phenylalanine was able to induce free radicals production. Therefore, our results strongly suggest that Phe at concentrations usually found in PKU induces oxidative stress and consequently cell death in astrocytes cultures. Considering the importance of the astrocytes for brain function, it is possible that these astrocytes alterations may contribute to the brain damage found in PKU patients.

Sertraline reduces glutamate uptake in human platelets

Mitochondrial damage and declines in ATP levels have been recently attributed to sertraline. The effects of sertraline on different parameters were investigated in washed platelets from 18 healthy male volunteers, after 24h of drug exposure. Sertraline toxicity was observed only at the highest concentrations, 30 and 100 μM, which significantly reduced platelet viability to 76 ± 3% and 20 ± 2%, respectively. The same concentrations significantly decreased total ATP to 73 ± 3% and 13 ± 2%, respectively. Basal values of glycogen were not significantly affected by sertraline treatment. Glutamate uptake was significantly reduced after treatment with 3, 30 and 100 μM, by 28 ± 6%, 32 ± 5% and 54 ± 4%, respectively. Our data showed that sertraline at therapeutic concentrations does not compromise platelet viability and ATP levels, but they suggest that in a situation where extracellular glutamate levels are potentially increased, sertraline might aggravate an excitotoxic condition.

Cofilin/actin rod formation by dysregulation of cofilin-1 activity as a central initial step in neurodegeneration

Cofilin-1 protein, which main function is to regulate actin cytoskeleton dynamics, appears to be involved with many steps in the neurotoxicity processes found in neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD). As the dynamics of actin filaments play a major role in several cellular processes, the primary involvement of cofilin-1 dysfunctions in the pathophysiology of these disorders may be related to a cytoskeleton stress. However, recently cofilin-1 has also been related to other biological processes such as cell death by apoptosis. In both cases, ATP depletion associated with the presence of reactive species and other stressors regulate cofilin-1 by inducing the formation of aggregates composed primarily by actin and cofilin-1, known as cofilin/actin rods. These structures seem to be formed initially as a neuroprotective response to mitochondrial damage; but once the stressor persists they are thought to act as inducers of further impairments and loss of neuronal functions. Therefore, here we provide a brief overview of the current knowledge about the central role of cofilin/actin rods formation, where its dysregulation and malfunction might be the trigger to neurodegeneration.

Effects of 47C allele (rs4880) of the SOD2 gene in the production of intracellular reactive species in peripheral blood mononuclear cells with and without lipopolysaccharides induction

Challenging of peripheral blood mononuclear cells (PBMCs) with lipopolysaccharides (LPS) has been shown to activate monocytes and macrophages, leading to the production of pro-inflammatory cytokines and reactive oxygen species (ROS). Manganese superoxide dismutase (MnSOD) is an important enzyme that may play a central role in the response to oxidative stress. 47C> T SNP of the SOD2 gene, the -9Val MnSOD is less efficient than the -9Ala version. We have previously characterized the cellular redox status of human PBMCs expressing either -9Ala (CC) or -9Val (TT) SOD2 and analyzed the responses of these cells to oxidative stress induced by LPS. Due to the observed alterations in the activities of these antioxidant enzymes, we decided to investigate their immunocontent and analyze the production of intracellular oxidants, as well as any resulting DNA damage. PBMCs were isolated from the blood of 30 healthy human volunteers (15 volunteers per allele). We then analyzed levels of nitrite, DNA damage by comet assay, TNF-α, carboxymethyl lysine and nitrotyrosine and assessed production of intracellular reactive species by the DCFH-DA-based assay and western blots were used to analyze protein levels. Our results show that there occurs an increase in nitric oxide production in both allele groups after challenge with LPS. A significant increase in DNA damage was observed in PBMCs after an 8-h LPS challenge. Cells expressing the SOD2 47C allele quickly adapt to a more intense metabolism by upregulating cellular detoxification mechanisms. However, when these cells are stressed over a long period, they accumulate a large quantity of toxic metabolic byproducts.

Effects of chronic caloric restriction on kidney and heart redox status and antioxidant enzyme activities in Wistar rats

Caloric restriction (CR) has been associated with health benefits and these effects have been attributed, in part, to modulation of oxidative status by CR; however, data are still controversial. Here, we investigate the effects of seventeen weeks of chronic CR on parameters of oxidative damage/modification of proteins and on antioxidant enzyme activities in cardiac and kidney tissues. Our results demonstrate that CR induced an increase in protein carbonylation in the heart without changing the content of sulfhydryl groups or the activities of superoxide dismutase and catalase (CAT). Moreover, CR caused an increase in CAT activity in kidney, without changing other parameters. Protein carbonylation has been associated with oxidative damage and functional impairment; however, we cannot exclude the possibility that, under our conditions, this alteration indicates a different functional meaning in the heart tissue. In addition, we reinforce the idea that CR can increase CAT activity in the kidney. [BMB Reports 2012; 45(11): 671-676]