Repurposing A549 Adenocarcinoma Cells: New Options for Drug Discovery

Molecular Dynamics-Guided Repositioning of FDA-Approved Drugs for PD-L1 Inhibition with In Vitro Anticancer Potential

Programmed death-ligand 1 (PD-L1) is a crucial immune checkpoint protein that tumors often exploit to evade immune surveillance. This study systematically screened a library of 1031 FDA-approved drugs using a high-throughput molecular dynamics approach to identify potential inhibitors targeting PD-L1. From this screening, five promising compounds-vorapaxar, delafloxacin, tenofovir disoproxil, pivmecillinam, and fursultiamine-showed significant binding affinities to PD-L1 and demonstrated cytotoxic activity against A549 lung tumor cells. These candidates were further evaluated through extended molecular dynamics simulations lasting up to 150 ns to assess their structural stability, residue fluctuations, and binding free energy. Among the identified compounds, pivmecillinam demonstrated the most favorable results, exhibiting stable binding interactions and a binding free energy of -18.01 kcal/mol, comparable to that of the known PD-L1 inhibitor BMS-1. These findings suggest that pivmecillinam has promising immunomodulatory potential and could serve as a candidate for further development in cancer immunotherapy. Overall, this study underscores the value of integrating high-throughput MD and experimental approaches for drug repositioning to identify novel therapeutic agents.

An Overview of the Bioactivity of Spontaneous Medicinal Plants Suitable for the Improvement of Lung Cancer Therapies

Lung cancer is the second cause of death in the world, being the most common type of cancer. Conventional therapies are not always recommended due to the particularities of patients. Thus, there is a need to develop new anticancer therapeutic agents. Medicinal plants constitute a source of bioactive compounds with therapeutic potential in lung cancer. The purpose of our narrative review is to evaluate and summarize the main studies on the cytotoxic effects of ten medicinal plants and their extracts, volatile oils, and bioactive compounds. We have also included studies that reported protective effects of these natural products against chemotherapy-induced toxicity. Studies were identified by assessing five databases using specific keywords. The investigated natural products possess cytotoxic effects on lung cancer cell cultures. Several mechanisms of action have been proposed including cell death by apoptosis, necrosis or autophagy, cell cycle arrest, the modulation of signaling pathways (PI3K/Akt and MAPK), the inhibition of migration, invasion and metastasis, antiangiogenesis, and targeting inflammation. Different bioactive compounds exhibit protective effects against chemotherapy-induced toxicity. Studies have shown promising results. To develop new therapeutic agents useful in treating lung cancer, the plants included in this review should be more deeply investigated to reveal their molecular mechanisms of action.

Necroptotic Suppression of Lung Cancer Cell Proliferation and Migration: A Comprehensive In Vitro and In Silico Study to Determine New Molecular Targets for Pexidartinib

In this study, the cytotoxic effects of pexidartinib (PLX), a tyrosine kinase inhibitor approved for tenosynovial giant cell tumor through inhibition of colony-stimulating factor 1 receptor (CSF1R), against A549 lung adenocarcinoma cells and Beas-2B healthy bronchial cells were investigated by in detailed in-vitro and in-silico studies. Through MTT assays, PLX demonstrated significant inhibition of A549 cell viability with IC50 values of 2.15 and 1.3 µM at 24 and 48 h, respectively, while having minimal effects on Beas-2B cells, with IC50 values of 36.2 and 9.3 µM. The high selectivity index indicates PLX's preferential action against cancerous cells. The mechanism of cell death induced by PLX was further explored using Annexin V/PI staining and flow cytometry, revealing that PLX primarily induces necrosis in A549 cells, with an increase in necrotic cell populations and reduced efficacy at higher concentrations. Western blot analysis showed an upregulation of necroptosis markers (RIP3 and pMLKL) in A549 cells, while apoptotic markers like Caspase-3 remained unchanged. In addition, wound healing assays demonstrated that PLX significantly inhibits A549 cell migration in a dose-dependent manner. Molecular docking studies identified key amino acids involved in PLX binding interactions with target proteins. RIPK1 showed the strongest binding affinity. MD simulations revealed that the PLX-VEGFR2 complex was the most stable. As conclusion, PLX, although approved for tenosynovial giant cell tumors, shows promising potential for lung adenocarcinoma treatment. It selectively inhibits cancer cell viability, induces necroptosis, and reduces cell migration. Its stronger binding to RIPK1 and VEGFR2 more than CSF1R.

Evaluation of expanded 2-aminobenzothiazole library as inhibitors of a model histidine kinase and virulence suppressors in Pseudomonas aeruginosa

Bacterial resistance to antibiotics is a rapidly increasing threat to human health. New strategies to combat resistant organisms are desperately needed. One potential avenue is targeting two-component systems, which are the main bacterial signal transduction pathways used to regulate development, metabolism, virulence, and antibiotic resistance. These systems consist of a homodimeric membrane-bound sensor histidine kinase, and a cognate effector, the response regulator. Histidine kinases play an essential role in the regulation of multiple virulence mechanisms including toxin production, immune evasion, and antibiotic resistance. Targeting virulence, as opposed to development of bactericidal compounds, could reduce evolutionary pressure for acquired resistance. Additionally, compounds targeting the highly conserved catalytic and adenosine triphosphate-binding (CA) domain have the potential to impair multiple two-component systems that regulate virulence in one or more pathogens. We conducted in vitro structure-activity relationship studies of 2-aminobenzothiazole-based inhibitors designed to target the CA domain. We found that these compounds, which inhibit the model histidine kinase, HK853 from Thermotoga maritima, have anti-virulence activities inPseudomonas aeruginosa, reducing motility phenotypes and toxin production associated with the pathogenic functions of this bacterium.

Standardized Protocol for Resazurin-Based Viability Assays on A549 Cell Line for Improving Cytotoxicity Data Reliability

The A549 cell line has become a cornerstone in biomedical research, particularly in cancer studies and serves as a critical tool in cytotoxicity studies and drug screening where it is used to evaluate the impact of pharmaceutical compounds on cellular viability. One of the most widely adopted methods for viability assessment, which is also used in evaluating drug cytotoxicity, is the resazurin-based assay. This assay exploits the ability of living cells to convert resazurin into fluorescent resorufin, providing a reliable indicator of metabolic activity. By measuring this conversion, cell viability can be estimated. Resazurin assay is extensively used for evaluating cytotoxic effects on various cell lines, including A549 cells, thereby bridging the gap between in vitro experimentation and drug development. However, frequent data inconsistencies in pre-clinical drug screening highlight the critical need for standardization to ensure reliability and reproducibility. This manuscript addresses these challenges by describing the optimization of resazurin-based viability assays for A549 cells in both 2D cultures and 3D fibrin gel models. By optimizing this test, the study aims to enhance the reliability of cytotoxicity results and introduces a new standard operating procedure, thus providing consistent results with minimal measurement uncertainty. This standardization is crucial for advancing drug screening and ensuring robust research findings.

Exploring hypoxia-induced ncRNAs as biomarkers and therapeutic targets in lung cancer

Lung cancer is a deadly disease, causing nearly 20 % of all cancer deaths globally. A key factor in lung cancer's development and resistance to treatment is hypoxia, a condition where tumor cells experience low oxygen levels. In this low-oxygen environment, special molecules called non-coding RNAs (ncRNAs) become critical players. NcRNAs, including lncRNAs, miRNAs, circRNAs, and siRNAs, control how genes function and how cells behave. Some ncRNAs, like HIF1A-AS2 and HOTAIR, are linked to the aggressive spread of lung cancer, making them potential targets for therapy. Others, like certain miRNAs, show promise as early detection tools due to their influence on tumor blood vessel formation and metabolism. This complex interplay between hypoxia and ncRNAs is crucial for understanding lung cancer. For example, circRNAs can control the activity of miRNAs, impacting how tumors respond to low oxygen. Additionally, siRNAs offer a potential strategy to overcome treatment resistance caused by hypoxia. By studying the intricate relationship between hypoxia and ncRNAs, scientists hope to uncover new biomarkers for lung cancer. This knowledge will pave the way for developing more effective and targeted treatments for this devastating disease.

Metformin alleviates benzo[a]pyrene-induced alveolar injury by inhibiting necroptosis and protecting AT2 cells

Exposure to benzo[a]pyrene (B[a]P) has been linked to lung injury and carcinogenesis. Airway epithelial cells express the B[a]P receptor AHR, so B[a]P is considered to mainly target airway epithelial cells, whereas its potential impact on alveolar cells remains inadequately explored. Metformin, a first-line drug for diabetes, has been shown to exert anti-inflammatory and tissue repair-promoting effects under various injurious conditions. Here, we explored the effect of chronic B[a]P exposure on alveolar cells and the impact of metformin on B[a]P-induced lung injury by examining the various parameters including lung histopathology, inflammation, fibrosis, and related signal pathway activation. MLKL knockout (Mlkl-/-) and AT2-lineage tracing mice (SftpcCre-ERT2;LSL-tdTomatoflox+/-) were used to delineate the role of necroptosis in B[a]P-induced alveolar epithelial injury and repair. Mice receiving weekly administration of B[a]P for 6 weeks developed a significant alveolar damaging phenotype associated with pulmonary inflammation, fibrosis, and activation of the necroptotic cell death pathway. These effects were significantly relieved in MLKL null mice. Furthermore, metformin treatment, which were found to promote AMPK phosphorylation and inhibit RIPK3, as well as MLKL phosphorylation, also significantly alleviated B[a]P-induced necroptosis and lung injury phenotype. However, the protective efficacy of metformin was rendered much less effective in Mlkl null mice or by blocking the necroptotic pathway with RIPK3 inhibitor. Our findings unravel a potential protective efficacy of metformin in mitigating the detrimental effects of B[a]P exposure on lung health by inhibiting necroptosis and protecting AT2 cells.

Hypoxia Modulates Radiosensitivity and Response to Different Radiation Qualities in A549 Non-Small Cell Lung Cancer (NSCLC) Cells

Hypoxia-induced radioresistance reduces the efficacy of radiotherapy for solid malignancies, including non-small cell lung cancer (NSCLC). Cellular hypoxia can confer radioresistance through cellular and tumor micro-environment adaptations. Until recently, studies evaluating radioresistance secondary to hypoxia were designed to maintain cellular hypoxia only before and during irradiation, while any handling of post-irradiated cells was carried out in standard oxic conditions due to the unavailability of hypoxia workstations. This limited the possibility of simulating in vivo or clinical conditions in vitro. The presence of molecular oxygen is more important for the radiotoxicity of low-linear energy transfer (LET) radiation (e.g., X-rays) than that of high-LET carbon (12C) ions. The mechanisms responsible for 12C ions' potential to overcome hypoxia-induced radioresistance are currently not fully understood. Therefore, the radioresistance of hypoxic A549 NSCLC cells following exposure to X-rays or 12C ions was investigated along with cell cycle progression and gene expression by maintaining hypoxia before, during and after irradiation. A549 cells were incubated under normoxia (20% O2) or hypoxia (1% O2) for 48 h and then irradiated with X-rays (200 kV) or 12C ions (35 MeV/n, LET ~75 keV/µm). Cell survival was evaluated using colony-forming ability (CFA) assays immediately or 24 h after irradiation (late plating). DNA double-strand breaks (DSBs) were analyzed using γH2AX immunofluorescence microscopy. Cell cycle progression was determined by flow cytometry of 4',6-diamidino-2-phenylindole-stained cells. The global transcription profile post-irradiation was evaluated by RNA sequencing. When hypoxia was maintained before, during and after irradiation, hypoxia-induced radioresistance was observed only in late plating CFA experiments. The killing efficiency of 12C ions was much higher than that of X-rays. Cell survival under hypoxia was affected more strongly by the timepoint of plating in the case of X-rays compared to 12C ions. Cell cycle arrest following irradiation under hypoxia was less pronounced but more prolonged. DSB induction and resolution following irradiation were not significantly different under normoxia and hypoxia. Gene expression response to irradiation primarily comprised cell cycle regulation for both radiation qualities and oxygen conditions. Several PI3K target genes involved in cell migration and cell motility were differentially upregulated in hypoxic cells. Hypoxia-induced radioresistance may be linked to altered cell cycle response to irradiation and PI3K-mediated changes in cell motility and migration in A549 cells rather than less DNA damage or faster repair.

A semiconductor 96-microplate platform for electrical-imaging based high-throughput phenotypic screening

High-content imaging for compound and genetic profiling is popular for drug discovery but limited to endpoint images of fixed cells. Conversely, electronic-based devices offer label-free, live cell functional information but suffer from limited spatial resolution or throughput. Here, we introduce a semiconductor 96-microplate platform for high-resolution, real-time impedance imaging. Each well features 4096 electrodes at 25 µm spatial resolution and a miniaturized data interface allows 8× parallel plate operation (768 total wells) for increased throughput. Electric field impedance measurements capture >20 parameter images including cell barrier, attachment, flatness, and motility every 15 min during experiments. We apply this technology to characterize 16 cell types, from primary epithelial to suspension cells, and quantify heterogeneity in mixed co-cultures. Screening 904 compounds across 13 semiconductor microplates reveals 25 distinct responses, demonstrating the platform's potential for mechanism of action profiling. The scalability and translatability of this semiconductor platform expands high-throughput mechanism of action profiling and phenotypic drug discovery applications.

TNF-α and MMPs mediated mucus hypersecretion induced by cigarette smoke: An in vitro study

Cigarette smoke is one of the leading causes of oxidative stress due to high levels of free radicals, which in turn leads to the degradation of alveolar cell walls and development of emphysema. Cigarette smoking has been linked to chronic bronchitis, Chronic Obstructive Pulmonary Disease (COPD) and lung cancer as well. The aim of the present study was to observe the effect of cigarette smoke extract (CSE) on TNF-α and MMPs mediated mucus hypersecretion in A549 cell line. The MTT experiments showed that CSE caused a dose-dependent decline in the level of viability of A549 cells. In addition, AO/PI and Mitotracker Red staining assays demonstrated that CSE caused the A549 cells to undergo apoptosis. This was determined by observing the reduction in mitochondrial membrane potential. CSE was found to be responsible for the formation of intracellular ROS, which was observed by DCFDA staining through fluorescence microscopy. Approximately 65% migration rate was decreased in 20% CSE exposed cells. CSE exposure led to the significantly increased mRNA levels of TNF-α, MMP-7, and MMP-12, in comparison to the control cells. Additionally, the expression of MUC5AC and MUC5B was provoked by CSE as well. Human epithelial cells are stimulated by TNF-α and MMPs secreted mucus, as shown by expression of MUC5AC and MUC5B. CSE could induce mucus in lungs through TNF-α and MMPs mediated pathways.

A semiconductor 96-microplate platform for electrical-imaging based high-throughput phenotypic screening

Profiling compounds and genetic perturbations via high-content imaging has become increasingly popular for drug discovery, but the technique is limited to endpoint images of fixed cells. In contrast, electronic-based devices offer label-free, functional information of live cells, yet current approaches suffer from low-spatial resolution or single-well throughput. Here, we report a semiconductor 96-microplate platform designed for high-resolution real-time impedance "imaging" at scale. Each well features 4,096 electrodes at 25 µm spatial resolution while a miniaturized data interface allows 8× parallel plate operation (768 total wells) within each incubator for enhanced throughputs. New electric field-based, multi-frequency measurement techniques capture >20 parameter images including tissue barrier, cell-surface attachment, cell flatness, and motility every 15 min throughout experiments. Using these real-time readouts, we characterized 16 cell types, ranging from primary epithelial to suspension, and quantified heterogeneity in mixed epithelial and mesenchymal co-cultures. A proof-of-concept screen of 904 diverse compounds using 13 semiconductor microplates demonstrates the platform's capability for mechanism of action (MOA) profiling with 25 distinct responses identified. The scalability of the semiconductor platform combined with the translatability of the high dimensional live-cell functional parameters expands high-throughput MOA profiling and phenotypic drug discovery applications.