Cytotoxic Events Research Articles

Unleashing of cytotoxic effects of thymoquinone-bovine serum albumin nanoparticles on A549 lung cancer cells

Abstract This research examines the cytotoxic consequences of thymoquinone-loaded bovine serum albumin nanoparticles (TQ-BSA NPs) on the A549 lung cancer cell line. UV-visible (UV–Vis) spectroscopy, Fourier transform infrared spectrophotometer (FT-IR), scanning electron microscopy (SEM), and dynamic light scattering (DLS) were employed to verify the biogenic TQ-BSA NPs’ size, shape, and distribution. UV–Vis spectrophotometry indicated peaks at 200–300 nm, 500–600 nm, and a prominent peak at 700–800 nm, confirming the presence of TQ-BSA NPs. The polydispersity index, as confirmed by DLS, indicated a solvent distribution in water, accompanied by a zeta potential value of 126.2 ± 46.8 mV. The average size of TQ-BSA NPs was confirmed to be 187 ± 8 nm by SEM. TQ-BSA NPs reduce colony formation in the A549 lung cancer cell line in a dose-dependent manner relative to the control group. Protein expression analysis indicated that TQ-BSA NPs promoted programmed cell death by increasing pro-apoptotic levels and decreasing anti-apoptotic levels. TQ-BSA NPs demonstrated inhibition of cancer cell proliferation and promotion of apoptosis and exhibited significant efficacy against cancer cells at low concentrations. As a result, they have the makings of a promising chemotherapeutic agent for low-dose, long-term administration.

Ribosome Quality Control mitigates the cytotoxicity of ribosome collisions induced by 5-Fluorouracil.

Ribosome quality control (RQC) resolves collided ribosomes, thus preventing their cytotoxic effects. The chemotherapeutic agent 5-Fluorouracil (5FU) is best known for its misincorporation into DNA and inhibition of thymidylate synthase. However, while a major determinant of 5FU's anticancer activity is its misincorporation into RNAs, the mechanisms by which cancer cells overcome the RNA-dependent 5FU toxicity remain ill-defined. Here, we report a role for RQC in mitigating the cytotoxic effects of 5FU. We show that 5FU treatment results in rapid induction of the mTOR signalling pathway, enhanced rate of mRNA translation initiation, and increased ribosome collisions. Consistently, a defective RQC exacerbates the 5FU-induced cell death, which is mitigated by blocking mTOR pathway or mRNA translation initiation. Furthermore, 5FU treatment enhances the expression of the key RQC factors ZNF598 and GIGYF2 via an mTOR-dependent post-translational mechanism. This adaptation likely mitigates the cytotoxic consequences of increased ribosome collisions upon 5FU treatment.

S-allyl-cysteine triggers cytotoxic events in rat glioblastoma RG2 and C6 cells and improves the effect of temozolomide through the regulation of oxidative responses

Glioblastoma (GBM) is an aggressive form of cancer affecting the Central Nervous System (CNS) of thousands of people every year. Redox alterations have been shown to play a key role in the development and progression of these tumors as Reactive Oxygen Species (ROS) formation is involved in the modulation of several signaling pathways, transcription factors, and cytokine formation. The second-generation oral alkylating agent temozolomide (TMZ) is the first-line chemotherapeutic drug used to treat of GBM, though patients often develop primary and secondary resistance, reducing its efficacy. Antioxidants represent promising and potential coadjutant agents as they can reduce excessive ROS formation derived from chemo- and radiotherapy, while decreasing pharmacological resistance. S-allyl-cysteine (SAC) has been shown to inhibit the proliferation of several types of cancer cells, though its precise antiproliferative mechanisms remain poorly investigated. To date, SAC effects have been poorly explored in GBM cells. Here, we investigated the effects of SAC in vitro, either alone or in combination with TMZ, on several toxic and modulatory endpoints—including oxidative stress markers and transcriptional regulation—in two glioblastoma cell lines from rats, RG2 and C6, to elucidate some of the biochemical and cellular mechanisms underlying its antiproliferative properties. SAC (1–750 µM) decreased cell viability in both cell lines in a concentration-dependent manner, although C6 cells were more resistant to SAC at several of the tested concentrations. TMZ also produced a concentration-dependent effect, decreasing cell viability of both cell lines. In combination, SAC (1 µM or 100 µM) and TMZ (500 µM) enhanced the effects of each other. SAC also augmented the lipoperoxidative effect of TMZ and reduced cell antioxidant resistance in both cell lines by decreasing the TMZ-induced increase in the GSH/GSSG ratio. In RG2 and C6 cells, SAC per se had no effect on Nrf2/ARE binding activity, while in RG2 cells TMZ and the combination of SAC + TMZ decreased this activity. Our results demonstrate that SAC, alone or in combination with TMZ, exerts antitumor effects mediated by regulatory mechanisms of redox activity responses. SAC is also a safe drug for testing in other models as it produces non-toxic effects in primary astrocytes. Combined, these effects suggest that SAC affords antioxidant properties and potential antitumor efficacy against GBM.

Safety and efficacy indicators of guarana and Brazil nut extract carried in nanoparticles of coenzyme Q10: Evidence from human blood cells and red earthworm experimental model

This study characterized a nanosupplement based on coenzyme Q10 containing guarana (Paullinia cupana) and Brazil nuts oil (Bertholetia excelsa) (G-Nut). Determined cytotoxic and oxi-immunomodulatory effects on human peripheral blood mononuclear cells (PBMCs) and its effect on mortality of red Californian earthworms (Eisenia fetida) and on the immune efficiency of its coelomocytes immune by in vitro exposure to yeast dead microorganism. The cytotoxic and immunomodulatory effects of G-Nut and the GN-Free extract (0.25–3 mg/mL) were determined in PBMC cultures. Apoptotic, oxidative, and inflammatory markers were determined using biochemical, immunological, and molecular protocols. The effects of G-Nut and GN-Free extracts on mortality and immune efficiency were investigated in earthworms. G-Nut and GN-Free did not induce cytotoxic events in PBMCs, triggering the decrease in apoptotic (caspases 3 and 8) gene expression, lipid and protein oxidation levels, or pro-inflammatory cytokine levels. G-Nut and GN-Free did not trigger earthworm mortality and improved coelomocyte immune efficiency by increasing Eisenia neutrophil extracellular DNA traps and brown body formation when exposed to dead yeasts. The G-Nut nanoformulation is safe and can be used as a new form of food supplement by oral or transdermal delivery.

Production of mono and bilayer devices for wound dressing by coupling of electrospinning and supercritical impregnation techniques

In this paper, electrospinning and supercritical impregnation were coupled to produce polyurethane fibrous membranes loaded with mesoglycan and lactoferrin. The proposed methodology allowed the production of three skin wound healing bilayer systems: a first system containing mesoglycan loaded through electrospinning and lactoferrin loaded by supercritical impregnation, a second system where the use of the two techniques was reversed, and a third sample where the drugs were both encapsulated through a one-step process. SEM analysis demonstrated the formation of microfibers with a homogeneous drug distribution. The highest loadings were 0.062 g/g for mesoglycan and 0.013 g/g for lactoferrin. Then, hydrophilicity and liquid retention analyses were carried out to evaluate the possibility of using the manufacturers as active patches. The kinetic profiles, obtained through in vitro tests conducted using a Franz diffusion cell, proved that the diffusion of the active drugs followed a double-step release before attaining the equilibrium after about 30 h. When the electrospun membranes were placed in contact with HUVEC, HaCaT, and BJ cell lines, as human endothelial cells, keratinocytes, and fibroblasts, respectively, no cytotoxic events were assessed. Finally, the capacity of the most promising system to promote the healing process was performed by carrying out scratch tests on HaCat cells.

NB compounds are potent and efficacious FOXM1 inhibitors in high-grade serous ovarian cancer cells

BackgroundGenetic studies implicate the oncogenic transcription factor Forkhead Box M1 (FOXM1) as a potential therapeutic target in high-grade serous ovarian cancer (HGSOC). We evaluated the activity of different FOXM1 inhibitors in HGSOC cell models.ResultsWe treated HGSOC and fallopian tube epithelial (FTE) cells with a panel of previously reported FOXM1 inhibitors. Based on drug potency, efficacy, and selectivity, determined through cell viability assays, we focused on two compounds, NB-73 and NB-115 (NB compounds), for further investigation. NB compounds potently and selectively inhibited FOXM1 with lesser effects on other FOX family members. NB compounds decreased FOXM1 expression via targeting the FOXM1 protein by promoting its proteasome-mediated degradation, and effectively suppressed FOXM1 gene targets at both the protein and mRNA level. At the cellular level, NB compounds promoted apoptotic cell death. Importantly, while inhibition of apoptosis using a pan-caspase inhibitor rescued HGSOC cells from NB compound-induced cell death, it did not rescue FOXM1 protein degradation, supporting that FOXM1 protein loss from NB compound treatment is specific and not a general consequence of cytotoxicity. Drug washout studies indicated that FOXM1 reduction was retained for at least 72 h post-treatment, suggesting that NB compounds exhibit long-lasting effects in HGSOC cells. NB compounds effectively suppressed both two-dimensional and three-dimensional HGSOC cell colony formation at sub-micromolar concentrations. Finally, NB compounds exhibited synergistic activity with carboplatin in HGSOC cells.ConclusionsNB compounds are potent, selective, and efficacious inhibitors of FOXM1 in HGSOC cells and are worthy of further investigation as HGSOC therapeutics.

Abstract 4718: Reclaiming a dirty drug: What is the context of vulnerability to arsenic trioxide in glioblastoma

Abstract Glioblastoma (GBM) is the most prevalent type of malignant tumor within the central nervous system. There is a growing demand to develop and adapt new therapeutic options in order to combat the five-year survival rate of 6.8% and improve patient quality of life. Arsenic trioxide (ATO) is the standard of care for myelodysplasia and relapsed or refractory acute promyelocytic leukemia. While currently being classified to have an idiopathic mechanism of action, two specific cytotoxic consequences of ATO have emerged: MNK1 activity and oxidative stress. Across six GBM PDX models a 20-fold difference in sensitivity manifests, indicative of underlying innate sensitivity or resistance to ATO. To correlate this to the proposed mechanisms of action, we observed ATO’s effect on MNK1 activity through eIF4E phosphorylation and glutathione (GSH) levels following treatment. A subset of GBM models exhibited a marked upregulation of eIF4E phosphorylation following treatment with 2 uM ATO. Of the six models, three were chosen to undergo further testing to observe whether this upregulation showed a consistent dose-dependent relationship across the models and correlated with vulnerability to ATO. Combination therapy with the MNK1 inhibitor, ETC-206, displayed mild to moderate synergy on overall cell viability and strong synergy when observing its effects on the glioma stem cell population. This preferential effect on the GSC populations suggests that MNK1i based combination strategies may show greater effectiveness in vivo than indicated by our previous in vitro studies. Nutraceuticals targeting GSH synthesis, Chrysin and Silibinin, displayed a 0.95 to 1.4-fold decrease in ATO IC50 values across all 6 models. To observe whether each nutraceutical impacted GSH levels consistently across all of the tested models, we measured GSH levels following treatment for each individual compound and their combination treatments. These findings further implicate MNK1 activity and cellular response to oxidative stress as markers of ATO sensitivity, however they are not the sole determinates of response. Understanding of the mechanism of action for idiopathic compounds may allow for the discovery of molecular signatures of sensitivity, improving patient selection for clinical trials and the development of new combination approaches to combat resistance in other tumor types. Citation Format: Charles Shaffer, Nanyun Tang, Yue Hao, Karen Fink, George Snipes, Bruce Mickey, Michael Berens. Reclaiming a dirty drug: What is the context of vulnerability to arsenic trioxide in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4718.

Combined use of multiparametric high-content-screening and in vitro circadian reporter assays in neurotoxicity evaluation.

Accumulating evidence indicates that chronic circadian rhythm disruption is associated with the development of neurodegenerative diseases induced by exposure to neurotoxic chemicals. Herein, we examined the relationship between cellular circadian rhythm disruption and cytotoxicity in neural cells. Moreover, we evaluated the potential application of an in vitro cellular circadian rhythm assay in determining circadian rhythm disruption as a sensitive and early marker of neurotoxicant-induced adverse effects. To explore these objectives, we established an in vitro cellular circadian rhythm assay using human glioblastoma (U87 MG) cells stably transfected with a circadian reporter vector (PER2-dLuc) and determined the lowest-observed-adverse-effect levels (LOAELs) of several common neurotoxicants. Additionally, we determined the LOAEL of each compound on multiple cytotoxicity endpoints (nuclear size [NC], mitochondrial membrane potential [MMP], calcium ions, or lipid peroxidation) using a multiparametric high-content screening (HCS) assay using transfected U87 MG cells treated with the same neurotoxicants for 24 and 72h. Based on our findings, the LOAEL for cellular circadian rhythm disruption for most chemicals was slightly higher than that for most cytotoxicity indicators detected using HCS, and the LOAEL for MMP in the first 24h was the closest to that for cellular circadian rhythm disruption. Dietary antioxidants (methylselenocysteine and N-acetyl-l-cysteine) prevented or restored neurotoxicant-induced cellular circadian rhythm disruption. Our results suggest that cellular circadian rhythm disruption is as sensitive as cytotoxicity indicators and occurs early as much as cytotoxic events during disease development. Moreover, the in vitro cellular circadian rhythm assay warrants further evaluation as an early screening tool for neurotoxicants.

Diazoxide attenuates DOX-induced cardiotoxicity in cultured rat myocytes.

Doxorubicin (DOX)-induced cardiotoxicity is a well known clinical problem, and many investigations have been made of its possible amelioration. We have investigated whether diazoxide (DIA), an agonist at mitochondrial ATP-sensitive potassium channels (mitoKATP), could reverse DOX-induced apoptotic myocardial cell loss, in cultured rat cardiomyocytes. The role of certain proteins in this pathway was also studied. The rat cardiomyocyte cell line (H9c2) was treated with DOX, and also co-treated with DOX and DIA, for 24 h. Distribution of actin filaments, mitochondrial membrane potential, superoxide dismutase (SOD) activity, total oxidant and antioxidant status (TOS and TAS, respectively), and some protein expressions, were assessed. DOX significantly decreased SOD activity, increased ERK1/2 protein levels, and depolarised the mitochondrial membrane, while DIA co-treatment inhibited such changes. DIA co-treatment ameliorated DOX-induced cytoskeletal changes via F-actin distribution and mitoKATP structure. Co-treatment also decreased ERK1/2 and cytochrome c protein levels. Cardiomyocyte loss due to oxidative stress-mediated apoptosis is a key event in DOX-induced cytotoxicity. DIA had protective effects on DOX-induced cardiotoxicity, via mitoKATP integrity, especially with elevated SUR2A levels; but also by a cascade including SOD/AMPK/ERK1/2. Therefore, DIA may be considered a candidate agent for protecting cardiomyocytes against DOX chemotherapy.

Using Rapid Prototyping to Develop a Cell-Based Platform with Electrical Impedance Sensor Membranes for In Vitro RPMI2650 Nasal Nanotoxicology Monitoring.

Due to advances in additive manufacturing and prototyping, affordable and rapid microfluidic sensor-integrated assays can be fabricated using additive manufacturing, xurography and electrode shadow masking to create versatile platform technologies aimed toward qualitative assessment of acute cytotoxic or cytolytic events using stand-alone biochip platforms in the context of environmental risk assessment. In the current study, we established a nasal mucosa biosensing platform using RPMI2650 mucosa cells inside a membrane-integrated impedance-sensing biochip using exclusively rapid prototyping technologies. In a final proof-of-concept, we applied this biosensing platform to create human cell models of nasal mucosa for monitoring the acute cytotoxic effect of zinc oxide reference nanoparticles. Our data generated with the biochip platform successfully monitored the acute toxicity and cytolytic activity of 6 mM zinc oxide nanoparticles, which was non-invasively monitored as a negative impedance slope on nasal epithelial models, demonstrating the feasibility of rapid prototyping technologies such as additive manufacturing and xurography for cell-based platform development.

Abstract LB_B18: Rapid and reproducible scaffold free organoid formation for personalized medicine: Multiomic analysis of in-vitro cancer patient model

Abstract We have established a single cell derived 3D organoid culture platform, Rapid, Reproducible, Rare Cell 3D Expansion (R3CE), and demonstrated its ability to generate 3D organoids of solid tumors, normal tissues from surgical tissues and needle biopsies in one week. The successful banking of at least two passages with over 10^6 cells is over 90% (breast cancer ( n=7, stages I to IV), colorectal cancer (n = 9 stages I to III), hepatoma cancer (n = 2, stage IV), and ovarian cancer (n =2, stage IV)). The quick formation of patient derived organoids have been consistently passed over 20 passages, and their H&E staining, WES, and protein markers have shown their high fidelity from the original tissues and passages over 11th generation. The normal and tumor organoid pairs were recently tested for direct cytotoxic events by co-culturing with various immunotherapy, including CAR-T and autologous NK testing. This is the first 3D organoid system that does not require aggregation, or 3D scaffold such as matrigel system. Hence, it opens up the possibility for drug assays, from small molecules, large molecules to cell regiments. Citation Format: Ying-Chih Chang. Rapid and reproducible scaffold free organoid formation for personalized medicine: Multiomic analysis of in-vitro cancer patient model [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_B18.

Elevated Levels of Cytotoxicity, Cytokines, and Anti-SARS-CoV-2 Antibodies in Mild Cases of COVID-19.

Current evidence shows higher production of cytokines and antibodies against severe acute respiratory coronavirus 2 (SARS-CoV-2) in severe and critical cases of Coronavirus Disease 2019 (COVID-19) in comparison with patients with moderate or mild disease. A recent hypothesis proposes an important role of genotoxicity and cytotoxicity in the induction of the cytokine storm observed in some patients at later stages of the disease. Interestingly, in this study, we report significantly higher levels of interleukin (IL)-1β, IL-6, MCP-1, and IL-4 cytokines in mild COVID-19 patients versus severe cases, as well as a high frequency of karyorrhexis (median [Me] = 364 vs. 20 cells) and karyolysis (Me = 266 vs. 52 cells) in the mucosal epithelial cells of both groups of patients compared with uninfected individuals. Although we observed higher levels of anti-SARS-CoV-2 IgM and IgG antibodies in COVID-19 patients, IgM antibodies were significantly higher only in mild cases, for the N and the S viral antigens. High levels of IgG antibodies were observed in both mild and severe cases. Our results showed elevated concentrations of proinflammatory and anti-inflammatory cytokines in mild cases, which may reflect an active innate immune response and could be related to the higher IgM and IgG antibody levels found in those patients. In addition, we found that SARS-CoV-2 infection induces cytotoxic damage in the oral mucosa, highlighting the importance of studying the genotoxic and cytotoxic events induced by infection and its role in the pathophysiology of COVID-19.

Firing of Replication Origins Is Disturbed by a CDK4/6 Inhibitor in a pRb-Independent Manner.

Over the last decade, CDK4/6 inhibitors (palbociclib, ribociclib and abemaciclib) have emerged as promising anticancer drugs. Numerous studies have demonstrated that CDK4/6 inhibitors efficiently block the pRb-E2F pathway and induce cell cycle arrest in pRb-proficient cells. Based on these studies, the inhibitors have been approved by the FDA for treatment of advanced hormonal receptor (HR) positive breast cancers in combination with hormonal therapy. However, some evidence has recently shown unexpected effects of the inhibitors, underlining a need to characterize the effects of CDK4/6 inhibitors beyond pRb. Our study demonstrates how palbociclib impairs origin firing in the DNA replication process in pRb-deficient cell lines. Strikingly, despite the absence of pRb, cells treated with palbociclib synthesize less DNA while showing no cell cycle arrest. Furthermore, this CDK4/6 inhibitor treatment disturbs the temporal program of DNA replication and reduces the density of replication forks. Cells treated with palbociclib show a defect in the loading of the Pre-initiation complex (Pre-IC) proteins on chromatin, indicating a reduced initiation of DNA replication. Our findings highlight hidden effects of palbociclib on the dynamics of DNA replication and of its cytotoxic consequences on cell viability in the absence of pRb. This study provides a potential therapeutic application of palbociclib in combination with other drugs to target genomic instability in pRB-deficient cancers.

Random forest selected transcripts from multiple neurodegenerative diseases reveal common affected cellular processes

AbstractBackgroundNeurodegenerative diseases such as Alzheimer’s disease are associated with changes in specific molecular pathways involving metabolomic and biological processes active in both the central nervous system and vascular peripheral system. Each disease results in neurodegeneration in vulnerable regions and cell types specific to that disease and are expressed in whole blood as disease progresses. Machine learning can be applied to the entire blood transcriptome of neurodegenerative diseases providing information for a pathophysiological relationship and gives us the advantage of using the vast knowledge of gene expression to analyze pathways affected thereby guiding insight into possible treatment strategies. We applied our unique machine learning algorithm to public data sets for selection of transcripts that guide our discovery of affected pathways.MethodsWe used large public blood microarray mRNA expression datasets, with platforms of more than 30,000 probes covering 10,000 genes, to discover disease transcripts using a novel Random Forest algorithm which selected supervised predictors for six different neurodegenerative diseases including Alzheimer’s disease (AD), Parkinson’s disease (PD), behavioral variant frontotemporal dementia (FTD), amyotrophic lateral sclerosis (ALS), Huntington’s disease (HD), and Friedreich’s ataxia (FRDA).ResultsOur machine learning selection of transcript disease classifiers reveals that neurodegenerative diseases have common themes as well as unique individual differences. Molecular components which overlap across diseases might be considered neurodegeneration generalities or a result of mixed pathology, while differential components identified by selected feature transcripts may represent unique dysfunctions.ConclusionOur Random Forest algorithm selected important features hidden in mRNA expression values from blood of affected individuals of six neurodegenerative diseases compared to healthy controls. For each of the six diseases studied here, the selected features were categorized by pathway analysis into eight main functional groups. The dysfunction of any or multiple functional groups combined can lead to synapse and cell loss in these neurodegenerative diseases each with specific vulnerabilities in particular tissue and cell types. Vulnerability is usually associated with those cells vulnerable to the disease pathology and are often first to exhibit cell death from cytotoxic events such as neuroinflammation, mitochondrial dysfunction, transcription alterations, apoptosis, protein synthesis dysfunction, cytoskeletal changes, and ubiquitylation/proteasome stalls.

Study on Cellular Localization of Bin Toxin and its Apoptosis-inducing Effect on Human Nasopharyngeal Carcinoma Cells.

Bacterial pore-forming toxins, BinA and BinB together known as the binary toxin are potent insecticidal proteins, that share structural homology with antitumor bacterial parasporin-2 protein. The underlying molecular mechanism of Bin toxin-induced cancer cell cytotoxicity requires more knowledge to understand whether the toxin induced human cytotoxic effects occur in the same way as that of parasporin-2 or not. In this study, anticancer properties of Lysinibacillus sphaericus derived Bin toxin on HK1 were evaluated through MTT assay, morphological analysis and lactate dehydrogenase efflux assay. Induction of apoptosis was determined from RT-qPCR, caspase activity and cytochrome c release assay. Internalization pattern of Bin toxin in HK1 cells was studied by confocal laser-scanning microscopic analysis. Activated Bin toxin had strong cytocidal activity to HK1 cancer cell line at 24 h postinoculation. Both BinA and BinB treated HK1 cells showed significant inhibition of cell viability at 12 μM. Induction of apoptotic mediators from RT-qPCR and caspase activity analyses indicated the activation of programmed cell death in HK1 cells in response to Bin toxin treatment. Internalization pattern of Bin toxin studied by using confocal microscopy indicated the localization of BinA on cell surface and internalization of BinB in the cytoplasm of cancer cells as well as colocalization of BinA with BinB. Evaluation of cytochrome c release also showed the association of BinB and BinA+BinB with mitochondria. Bin toxin is a cytotoxic protein that induces cytotoxic and apoptotic events in HK1 cells, and may have high therapeutic potential as an anti-cancer agent.

Immune-Checkpoint Induced Skin Toxicity Masked as Squamous Cell Carcinoma: Case Report on Mimickers of Dermatological Toxicity with PD-1 Inhibition

Immune checkpoint inhibitors (ICI) are increasingly the mainstay of oncology treatment. Immune-related adverse events (irAEs) from ICI therapy differ from cytotoxic adverse events. Cutaneous irAEs are one of the most common irAEs and require careful attention to optimize the quality of life for oncology patients. These are two cases of patients with advanced solid-tumour malignancies treated with PD-1 inhibitor therapy. Both patients developed multiple pruritic hyperkeratotic lesions, which were initially diagnosed as squamous cell carcinoma from skin biopsies. The presentation as squamous cell carcinoma was atypical and, upon further pathology review, the lesions were more in keeping with a lichenoid immune reaction stemming from the immune checkpoint blockade. With the use of oral or topical steroids and immunomodulators, the lesions resolved. These cases emphasize that patients on PD-1 inhibitor therapy who develop lesions resembling squamous cell carcinoma on initial pathology may require an additional pathology review to assess for immune-mediated reactions, allowing appropriate immunosuppressive therapy to be initiated.

Changes in metabolic landscapes shape divergent but distinct mutational signatures and cytotoxic consequences of redox stress.

Mutational signatures discerned in cancer genomes, in aging tissues and in cells exposed to toxic agents, reflect complex processes underlying transformation of cells from normal to dysfunctional. Due to its ubiquitous and chronic nature, redox stress contributions to cellular makeover remain equivocal. The deciphering of a new mutational signature of an environmentally-relevant oxidizing agent, potassium bromate, in yeast single strand DNA uncovered a surprising heterogeneity in the mutational signatures of oxidizing agents. NMR-based analysis of molecular outcomes of redox stress revealed profound dissimilarities in metabolic landscapes following exposure to hydrogen peroxide versus potassium bromate. The predominance of G to T substitutions in the mutational spectra distinguished potassium bromate from hydrogen peroxide and paraquat and mirrored the observed metabolic changes. We attributed these changes to the generation of uncommon oxidizing species in a reaction with thiol-containing antioxidants; a nearly total depletion of intracellular glutathione and a paradoxical augmentation of potassium bromate mutagenicity and toxicity by antioxidants. Our study provides the framework for understanding multidimensional processes triggered by agents collectively known as oxidants. Detection of increased mutational loads associated with potassium bromate-related mutational motifs in human tumors may be clinically relevant as a biomarker of this distinct type of redox stress.

Abstract 4147: Activated pyroptosis prior to treatment marks a potential response to immunotherapy in cancers

Abstract Purpose: Immune checkpoint inhibitors (ICIs) have achieved remarkable survival improvement in multiple cancers by exerting anti-tumor effects through augmenting adaptive immunity. However, 60%-70% of patients showed primary resistance to ICIs, and the underlying mechanisms remained unclear. Pyroptosis is a programmed cell death accompanied by a robust inflammatory response with the secretion of pro-inflammatory molecules, and thus it has the potential to be a promising biomarker for immunotherapy. Methods: A dataset with the clinical and transcriptomic profiles was derived from 16 randomized controlled trials and studies on ICIs treatment in multiple solid tumors, including melanoma, urothelial cancer, non-small cell lung cancer, renal cell cancer, breast cancer, and esophageal cancer. The responder was defined as patients achieving complete or partial response, while the non-responder was defined as patients with stable or progressive disease. According to previous studies, we generated a cytotoxic pyroptosis-related gene set, including CASP1, CASP3, CASP4, CASP5, CASP8, GSDMB, GSMDC, GSDMD, GSDME, GZMA, GZMB, to explore the association of cytotoxic pyroptosis with response to ICIs. In addition, the previously defined gene set from the Gene Ontology working group that contains a pyroptosis-related gene set was also included to represent the level of total pyroptosis. Single sample Gene Set Enrichment Analysis (ssGSEA) was performed, and the fold-changes and p-values of gene sets were merged with the R package “MetaVolcanoR”. Patients in each subset were split by the median of the ssGSEA score of pyroptosis-related genes and identified as with relatively activated and inhibited pyroptosis, respectively. A P-value < 0.05 was considered significant. Results: A total of 1,407 patients were analyzed, including 475 responders and 932 non-responders. The ssGSEA revealed that both the pyroptosis and the cytotoxic pyroptosis gene sets were enriched in responders, while the cytotoxic pyroptosis-related gene set was one of the top five ones among the 545 enriched in responders. Moreover, the survival analysis showed that in urothelial and non-small cell lung cancer, patients with activated pyroptosis prior to treatment had better progression-free survival and overall survival after ICIs therapies. These results suggested that an activated status of pyroptosis, especially the pyroptotic process related to cytotoxic events, is a marker for better response to ICIs. Conclusions: The transcriptomic analysis of universal immunotherapy biomarkers identifies an pre-existing activated status of pyroptosis within the tumor microenvironment was associated with a better ICIs response across different cancer types, and thus these pyroptosis-related genes may serve as valuable immunotherapy markers and in silico fundamental tool for exploring pyroptosis in tumor immunity. Citation Format: Yumo Xie, Xiaolin Wang, Meijin Huang, Yanxin Luo, Huichuan Yu. Activated pyroptosis prior to treatment marks a potential response to immunotherapy in cancers. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4147.

The toxicity of nanoparticles and their interaction with cells: an in vitro metabolomic perspective.

Nowadays, nanomaterials (NMs) are widely present in daily life due to their significant benefits, as demonstrated by their application in many fields such as biomedicine, engineering, food, cosmetics, sensing, and energy. However, the increasing production of NMs multiplies the chances of their release into the surrounding environment, making human exposure to NMs inevitable. Currently, nanotoxicology is a crucial field, which focuses on studying the toxicity of NMs. The toxicity or effects of nanoparticles (NPs) on the environment and humans can be preliminary assessed in vitro using cell models. However, the conventional cytotoxicity assays, such as the MTT assay, have some drawbacks including the possibility of interference with the studied NPs. Therefore, it is necessary to employ more advanced techniques that provide high throughput analysis and avoid interferences. In this case, metabolomics is one of the most powerful bioanalytical strategies to assess the toxicity of different materials. By measuring the metabolic change upon the introduction of a stimulus, this technique can reveal the molecular information of the toxicity induced by NPs. This provides the opportunity to design novel and efficient nanodrugs and minimizes the risks of NPs used in industry and other fields. Initially, this review summarizes the ways that NPs and cells interact and the NP parameters that play a role in this interaction, and then the assessment of these interactions using conventional assays and the challenges encountered are discussed. Subsequently, in the main part, we introduce the recent studies employing metabolomics for the assessment of these interactions in vitro.

MXene‐Based Nanomaterials for Biomedical Applications: Healthier Substitute Materials for the Future

MXene‐based nanomaterial is a revolution 2D material achieving outstanding scientific attention owing to its universal characteristics for different applications (such as electronic appliances, power production, sensors, drug transfer, and biomedical). Although, the cytotoxic consequences of MXene have a considerable circumstance. Thus, rigorous investigation of the biocompatibility of MXene is a crucial prerequisite, formerly the preface to the human biological approach. Literature reveals functional outcomes wherever MXenes are used in vitro and in vivo cancer representatives. It affects drug transfer methods, sensoring electrodes, and assisting mechanisms for photothermal treatment and hyperthermy techniques. In this review, the synthesis process (such as top‐down and bottom‐up approaches) and properties (such as mechanical, electrical, optical, oxidative/thermal stability, and magnetic) of MXene‐based nanomaterials (NMs) are discussed. In addition, the different applications (such as tissue engineering, cancer theranostic, and other biomedical [such as drug delivery biosensors and surface‐enhanced Raman spectroscopy substrates for biomedical applications], antiviral, and immunomodulatory properties against SARS‐CoV‐2) of MXene‐based NMs are discussed in detail. Finally, the conclusion, existing challenges, and future outlooks are highlighted for more scope in this field.