CellTiter-Glo Assay Research Articles

EXTH-41. COMBINATION TREATMENT WITH RAF/MEK AND FAK INHIBITION ENHANCES TUMOR GROWTH INHIBITION IN MENINGIOMA

Abstract BACKGROUND Patients with meningiomas who have progressed after multimodal treatments face a significant shortage of viable therapeutic options. Recent advancements in the molecular understanding of meningiomas have identified the FAK and RAF/MEK signaling pathways as potential promising targets for progressive meningiomas. METHODS In vitro, we tested two human meningioma cell lines, IOMM-Lee (NF2 wild-type and CDKN2A loss) and CH157-MN (NF2 mutant). The cells were plated in Matrigel-coated wells, treated with defactinib (FAK inhibitor), VS-6766 (RAF/MEK inhibitor, avutometinib) and the combination over a 7-day period and assessed for cell viability using the CellTiter-Glo 3D assay. In vivo, we tested the efficacy of the FAK inhibitor VS-4718 (possessing favorable pharmacokinetic properties in mice) and RAF/MEK inhibitor VS-6766, both given daily via oral gavage, in athymic nude mice bearing IOMM-Lee or CH157-MN tumors. RESULTS In the matrigel assay, VS-6766 suppressed IOMM-Lee and CH157-MN cells in a dose dependent manner. The drug combination was mostly additive in IOMM-Lee cells. However, CH157-MN cells showed a strong synergistic response across all drug concentrations tested. In the IOMM-Lee flank tumor model, VS-4718 alone had no effect, while VS-6766 alone or in combination significantly reduced tumor growth and extended median survival from 25 days to 47 days (p < 0.05). In the CH157 flank tumor model, VS-4718 monotherapy did not affect tumor growth or survival, but VS-6766 monotherapy slowed tumor growth and increased median survival from 10 days to 31 days (p < 0.001). Combining both drugs further reduced tumor growth and extended median survival to 42 days (p < 0.001). CONCLUSION Treatment with FAK and RAF/MEK inhibitors showed synergistic or combination effects in the NF2 mutant CH157-MN model in vitro and in vivo. RAF/MEK inhibitor monotherapy was effective for the IOMM-Lee model (NF2 wild-type), without clear benefit of combining with the FAK inhibitor. Investigations in intracranial tumor models are underway.

The cumulative effect of compound heterozygous variants in TRPV3 caused Olmsted syndrome

BackgroundOlmsted syndrome (OS) is a rare genodermatosis predominantly inherited in an autosomal dominant manner, typically arising from gain-of-function (GOF) variants in the transient receptor potential channel vanilloid 3 (TRPV3). ObjectiveThis study aims to investigate potential mechanisms underlying OS in two cases presenting with an autosomal recessive inheritance pattern. MethodsNext-generation sequencing panel was employed to identify TRPV3 variants. TRPV3 plasmids carrying specific point variations were generated and transiently transfected into HEK293T cells. Electrophysiological patch-clamp techniques were utilized to record voltage-activated and ligand-activated currents. Celltiter-Glo luminescent assay was employed to analyze the cell viabilities. ResultsCompound heterozygous variants, c.1563G>C (p.W521C) and c.1376C>T (p.S459L), as well as c.1773G>C (p.L591F) and c.2186G>A (p.R729Q), were identified in the two OS patients respectively. Electrophysiological analysis of ligand-induced activation of TRPV3 variants demonstrated the closest correlation with clinical manifestations. All four variants displayed GOF channel activity characterized by increased sensitivity. Notably, W521C and L591F exhibited both heightened sensitivity and lower EC50 values for the TRPV3 agonist. Co-transfection with wild-type TRPV3 plasmids significantly rescued these effects. Cells co-transfected with the corresponding compound heterozygous variants exhibited intermediate electrophysiological characteristics. ConclusionsIn this study, we present two cases of OS by autosomal-recessive inheritance of TPRV3 variants. This study presents a notable observation of compound heterozygous GOF variants in TRPV3, highlighting their cumulative impact on clinical manifestations. Additionally, we advocate for the use of ligand-dependent ion channel activity assays to assess the pathogenicity of TRPV3 variants in OS.

Alamar Blue assay optimization to minimize drug interference and inter assay viability

Alamar Blue (AB) has become an increasingly popular reagent of choice for cell viability assays. We chose AB over other reagents such as MTT and Cell-Titer Glo due to its cost effectiveness and its ability to be a nondestructive assay. While analyzing the effect of osimertinib, an EGFR inhibitor on the non-small cell lung cancer cell line, PC-9, we noticed unexpected right-shifts of dose response curves as compared to the curves obtained by Cell Titer Glo assay. Here, we describe our modified AB assay method to avoid that right shift in dose response curves.•Removal of the drug containing medium prior to AB addition eliminated the falsely increased readings, giving comparable dose response curves as determined by Cell Titer Glo assay.•Plate-to-plate variability can be minimized by adding an appropriate concentration of a common fluorescence calibration standard to the assay plates to calibrate fluorimeter sensitivity.•Alamar Blue can be used as a continuous longitudinal assay to monitor cell growth or recovery from drug toxicity over time.

THE EPIGENETIC REGULATORY PROTEIN CBX2 AS A NOVEL THERAPEUTIC TARGET FOR GLIOBLASTOMA

Abstract AIMS Glioblastoma (GBM) is the deadliest and most common form of brain tumour. The average length of survival for GBM patients remains low, in part, due to a lack of targeted therapeutics. Identification and validation of novel therapeutic targets is therefore crucial. Chomobox 2 (CBX2; a component of polycomb repressive complex 1 (PRC1)), represses gene expression and has a pro-oncogenic role in several aggressive cancer subtypes. CBX2 expression is elevated in GBM, however, very little is known about its role in this deadly disease. We aim to assess the phenotypic and gene expression effects of preventing CBX2-chromatin interaction in patient-derived GBM cell models, and to determine the functional mechanisms by which CBX2 promotes GBM progression; thereby determining its potential as a novel therapeutic target. METHOD Crucial to impactful target validation is the use of translationally relevant models, this study utilises a 3D spheroid model, using patient-derived cells, which more closely recapitulates the in vivo tumour microenvironment. GBM cell monolayers and spheroids were treated with SW2_152F, a selective CBX2 inhibitor. The phenotypic effects of CBX2 inhibition were assessed by cell count, CellTiter-Glo viability assays, fluorescence microscopy, and flow cytometry. Genes and biological pathways differentially regulated following CBX2 inhibition were assessed by RNA-sequencing and Gene Set Enrichment Analysis (GSEA). RESULTS Inhibition of CBX2 induced cell death and reduced cell viability in both 2D and 3D GBM cultures. RNA-seq and GSEA of SW2_152F-treated cells identified dysregulation of gene signatures involved in pro-oncogenic MYC and E2F signalling pathways, and dysregulation of genes associated with G2/M cell cycle progression. CONCLUSION Preventing CBX2-chromatin interaction induces GBM cell death. Further research will identify CBX2- chromatin binding sites to characterise the activity and direct regulatory role of CBX2 in GBM. Furthermore, we will assess the phenotypic and gene expression effects of CBX2 inhibition and depletion on ex vivo maintained GBM tissue biopsies.

Novel repurposing of sulfasalazine for the treatment of adrenocortical carcinomas, probably through the SLC7A11/xCT-hsa-miR-92a-3p-OIP5-AS1 network pathway

BackgroundRecent multigenomic analysis of adrenocortical carcinomas (ACCs) identified SLC7A11/xCT as a novel biomarker. The Food and Drug Administration–approved anti-inflammatory drug, sulfasalazine (SAS), induces ferroptosis by blocking SLC7A11 expression. We hypothesize that SAS could be repurposed to target ACC cells. MethodsExpression of SLC7A11 and its association with ACC survival was analyzed using Gene Expression Profiling Interactive Analysis (GEPIA). The validated ACC cell lines NCI-H295R, ACC1, and ACC2 were grown in 2D culture. In vitro studies included the CellTiter-Glo assay to calculate viability, Western blot (WB) analysis for apoptosis and other target protein changes, reverse transcriptase polymerase chain reaction for steroidogenic enzyme changes, C11BODIPY for lipid peroxidation, and mass spectrometry for changes in lipids. ResultsThe Cancer Genome Atlas Program database analysis in GEPIA showed that SLC7A11 and linked long noncoding RNA OAP5-AS1 are highly expressed in ACC tumors versus normal adrenals (n = 77 vs 128; P < .05). This was associated with poor overall and disease-free survival with hazard ratios of 4.3 and 5.2 for SLC7A11 and 4.8 and 2.7 for OAP5-AS1, respectively. ACC cell line half-inhibitory maximum concentration values after 72-hour SAS treatment ranged from 412 nM (ACC1) to 799 nM (ACC2), and all showed cleavage of poly (ADP-ribose) polymerase, upregulation of p-Akt and p-ERK, and downregulation of GPX4 and SLC7A11 (P < .05) by WB analysis. Sphere formation, migration, and invasion assay showed inhibition, and lipid peroxidation using C11BODIPY, increase in intracellular iron, induction of oxidative stress, and significant upregulation of oxidized polyunsaturated fatty acid phospholipids (P < .05 each) by mass spectrometry suggests induction of ferroptosis. ConclusionSAS downregulates tSLC7A11 in ACCs, targets the Akt/ERK pathway and lipid metabolism, and induces cell death in vitro, warranting additional translational studies to define its therapeutic potential in ACC.

CD64+ fibroblast-targeted vilanterol and a STING agonist augment CLDN18.2 BiTEs efficacy against pancreatic cancer by reducing desmoplasia and enriching stem-like CD8+ T cells

ObjectiveThe objective of this study is to improve the efficacy of CLDN18.2/CD3 bispecific T-cell engagers (BiTEs) as a promising immunotherapy against pancreatic ductal adenocarcinoma (PDAC).DesignHumanised hCD34+/hCD3e+, Trp53R172HKrasG12DPdx1-Cre (KPC), pancreas-specific Cldn18.2...

Hsp70 Negatively Regulates Autophagy via Governing AMPK Activation, and Dual Hsp70-Autophagy Inhibition Induces Synergetic Cell Death in NSCLC Cells.

Proteostasis mechanisms, such as proteotoxic-stress response and autophagy, are increasingly recognized for their roles in influencing various cancer hallmarks such as tumorigenesis, drug resistance, and recurrence. However, the precise mechanisms underlying their coordination remain not fully elucidated. The aim of this study is to investigate the molecular interplay between Hsp70 and autophagy in lung adenocarcinoma cells and elucidate its impact on the outcomes of anticancer therapies in vitro. For this purpose, we utilized the human lung adenocarcinoma A549 cell line and genetically modified it by knockdown of Hsp70 or HSF1, and the H1299 cell line with knockdown or overexpression of Hsp70. In addition, several treatments were employed, including treatment with Hsp70 inhibitors (VER-155008 and JG-98), HSF1 activator ML-346, or autophagy modulators (SAR405 and Rapamycin). Using immunoblotting, we found that Hsp70 negatively regulates autophagy by directly influencing AMPK activation, uncovering a novel regulatory mechanism of autophagy by Hsp70. Genetic or chemical Hsp70 overexpression was associated with the suppression of AMPK and autophagy. Conversely, the inhibition of Hsp70, genetically or chemically, resulted in the upregulation of AMPK-mediated autophagy. We further investigated whether Hsp70 suppression-mediated autophagy exhibits pro-survival- or pro-death-inducing effects via MTT test, colony formation, CellTiter-Glo 3D-Spheroid viability assay, and Annexin/PI apoptosis assay. Our results show that combined inhibition of Hsp70 and autophagy, along with cisplatin treatment, synergistically reduces tumor cell metabolic activity, growth, and viability in 2D and 3D tumor cell models. These cytotoxic effects were exerted by substantially potentiating apoptosis, while activating autophagy via rapamycin slightly rescued tumor cells from apoptosis. Therefore, our findings demonstrate that the combined inhibition of Hsp70 and autophagy represents a novel and promising therapeutic approach that may disrupt the capacity of refractory tumor cells to withstand conventional therapies in NSCLC.

Novel 1,3,4-trisubstituted Pyrazolopyrimidine Derivatives Show Potent Antiproliferative Activity in Mantle Cell Lymphoma

Background: Pyrazolopyrimidine scaffold is an important pharmacophore in drug discovery. This pharmacophore has been reported to produce numerous biological activities, of which anticancer is an important one. The development of novel pyrazolopyrimidine derivatives is of great importance for antitumor drug research. Objective: Compound 6, a pyrazolopyrimidine derivative reported by our group, showed weak antiproliferative activity with IC50 values of over 30 μM against mantle cell lymphoma (MCL) cell lines. In this study, we will further perform the structural optimization of compound 6 to screen highly active pyrazolopyrimidine derivatives. Methods: A novel series of 1,3,4-trisubstituted pyrazolopyrimidine derivatives were synthesized and their structures were elucidated by 1H-NMR, 13C-NMR, and HRMS. The antiproliferative activities of target compounds against MCL cell lines (Mino, Jeko-1, and Z138) were evaluated by the CellTiter-Glo luminescent cell viability assay. The effect of representative compounds to induce apoptosis was evaluated by Annexin V/Propidium Iodide (PI)-binding assay. Mitochondrial membrane potential and reactive oxygen species (ROS) levels in 15c-treated Z138 cells were tested by JC-1 and DCFH-DA probes, respectively. Results: Most compounds demonstrated improved antiproliferative activity against MCL cell lines compared to the lead compound 6, especially 15c, 15f, 15g, 15j, and 15o, with IC50 values at low micromolar levels. In addition, compound 15c could induce apoptosis in a dose-dependent manner in Z138 cells through reduction of mitochondrial membrane potential and enhancing reactive oxygen species production. Conclusion: The results showed that 1,3,4-trisubstituted pyrazolopyrimidine derivatives could be valuable lead compounds for the further development of anti-lymphoma agents.

Semen Cannabis and Oleum Hyperici: Antileishmanial activity against Leishmania tropica promastigotes and intracellular amastigotes

The exploration of alternative agents and novel drug candidates for the effective treatment of cutaneous leishmaniasis has garnered significant attention, driven by the high cost, toxic effects, and the emergence of drug resistance associated with current therapeutic options. Plant extracts derived from Semen Cannabis, the seeds of the Cannabis sativa L. (hemp) plant, and Oleum Hyperici, the oily macerate of Hypericum perforatum L. (St. John's Wort) plant, were prepared by using solvents of varying polarity (n-hexane, chloroform, ethanol, and 60% aqueous ethanol). The primary objective of this study was to research in vitro and ex vivo antileishmanial efficacy of Semen Cannabis and Oleum Hyperici plant extracts against Leishmania tropica promastigotes and intracellular amastigotes. The efficacy of plant extracts against promastigotes were assessed using the cell counting by hemocytometer and the CellTiter-Glo assay. Additionally, their impact on infected THP-1 macrophages and the quantity of intracelluler amastigotes were investigated. Cytotoxicity was evaluated in THP-1 macrophages. Among the tested plant extracts, chloroform extract of Oleum Hyperici demonstrated significant antileishmanial activity against promastigotes (SI: 12.6) and intracellular amastigotes (SI: 16.8) of L. tropica without inducing cytotoxic effects and hold promise for further investigation as potential antileishmanial agents.

Novel Piperazine Derivatives of Vindoline as Anticancer Agents.

A series of novel vindoline-piperazine conjugates were synthesized by coupling 6 N-substituted piperazine pharmacophores at positions 10 and 17 of Vinca alkaloid monomer vindoline through different types of linkers. The in vitro antiproliferative activity of the 17 new conjugates was investigated on 60 human tumor cell lines (NCI60). Nine compounds presented significant antiproliferative effects. The most potent derivatives showed low micromolar growth inhibition (GI50) values against most of the cell lines. Among them, conjugates containing [4-(trifluoromethyl)benzyl]piperazine (23) and 1-bis(4-fluorophenyl)methyl piperazine (25) in position 17 of vindoline were outstanding. The first one was the most effective on the breast cancer MDA-MB-468 cell line (GI50 = 1.00 μM), while the second one was the most effective on the non-small cell lung cancer cell line HOP-92 (GI50 = 1.35 μM). The CellTiter-Glo Luminescent Cell Viability Assay was performed with conjugates 20, 23, and 25 on non-tumor Chinese hamster ovary (CHO) cells to determine the selectivity of the conjugates for cancer cells. These compounds exhibited promising selectivity with estimated half-maximal inhibitory concentration (IC50) values of 2.54 μM, 10.8 μM, and 6.64 μM, respectively. The obtained results may have an impact on the design of novel vindoline-based anticancer compounds.

P-266 Profiling redox effects induced by micro-nanoplastics in the female reproductive system: insights from human granulosa cells

Abstract Study question Are nano-microplastics (NMPs) taken up into human granulosa cells causing redox alterations? Summary answer NMPs enter into human granulosa cells and influence viability, energy production and antioxidant response. What is known already In recent decades, anthropogenic activities have increased the production of global plastic with millions of tons produced every year. Under the action of different physical, chemical or biological agents, plastic waste breaks down into (NMP) particles that propagate in the environment posing threats for human health. NMPs translocate from digestive tract to circulatory systems reaching organs and cells, including female gonads. Nevertheless, there is insufficient knowledge of their effects on reproductive functions in mammals to allow for an accurate risk assessment to be conducted and any risks managed in animal and human being contexts. Study design, size, duration Human ovarian granulosa cells (KGN cell line) were exposed to NMPs of different sizes (40 nm, 70 nm, 100 nm, and 200 nm) at concentrations ranging from 5 to 1000 μg/ml for 24 h and then processed for cellular and biochemical analyses Participants/materials, setting, methods NMPs uptake by granulosa cells was tested by the employment of fluorescent NMPs and observation under confocal laser scanning microscopy. Cell viability was assed by Cell Counting Kit8. The effects of NMPs on mitochondrial bioenergetics was evaluated by MitoStress kit (Seahorse Xfe96, Agilent). ATP production was evaluated by Cell Titer-Glo ATP assay kit (Promega). Key enzymes of antioxidant response were analysed at transcript and protein level by using real-time Taqman PCR and Western blotting, respectively. Main results and the role of chance We demonstrated that NMPs are taken up by granulosa cells at all tested concentrions along with significant decrease of cell vitality with all sizes and concentrations. Seahorse analysis revealed an altered bioenergetic profiles. ATP levels increase at 70, 100 and 200 nm (one way ANOVA p = 0.001) at all tested concentrations (one way ANOVA p &amp;lt; 0.001). The gene and protein expression of catalase (CAT) superoxide dismutase 1 (SOD1) and superoxide dismutase 2 (SOD2) increased at 5 and 100 µg/ml with all sizes except 100 nm, whereas the level of sirtuins (SIRT1 and SIRT3) transcripts and protein decreased. Reduced levels of phosphorylated NRF2, the transcription factor that activates antioxidant responsive elements (ARE)-mediated gene expression were observed. Limitations, reasons for caution The use of human cell lines requires careful consideration when transferring to human testing. Wider implications of the findings Our results contribute to understanding the effects of NMPs on mammalian fertility in order to find possible protective approaches. Considering that the level of susceptibility of mammalian female germ cells to NMPs is still unknown, present results contribute to evidence-based strategies allowing living and working in a health promoting environment. Trial registration number Effects of combined exposure to nano/microplastics and plastic additives on mammalian female fertility (CUP E53D2301100006)

DIPG-38. VAL-083 IN COMBINATION WITH AZD1775 FOR THE TREATMENT OF DIFFUSE MIDLINE GLIOMA

Abstract BACKGROUND Diffuse midline gliomas (DMGs) are malignant pediatric brain tumors characterized by H3K27M mutation and global genome hypomethylation. This results in enhanced transcription of MGMT, a DNA-repair enzyme, rendering alkylating chemotherapeutics ineffective. Therefore, we investigated the efficacy of a functionally different DNA damaging agent, Val-083, that induces double strand breaks and triggers S/G2 phase cell cycle arrest for homologous DNA repair. We further evaluated its combined efficacy with Wee1 (G2/M checkpoint) inhibitor, AZD1775, to override cell cycle arrest and propel cells with DNA damage into premature mitosis and apoptosis. METHODS DMG cells were treated with increasing concentration of Val-083 and/or AZD1775 and their viability was evaluated using CellTiter-Glo luminescent assay. Next, the drugs’ mechanisms of action were investigated by immunoblotting for biomarkers involved in DNA damage response and cell cycle arrest. Flow cytometry was used to investigate cell cycle profile and apoptosis. Additionally, in vivo tumor growth inhibition and survival benefit were evaluated using zebrafish and mouse xenograft DMG models. RESULTS The IC50 values of Val-083 range between 0.69 and 4.38 µM while the IC50 values of AZD1775 range between 0.22 to 0.98 µM. Combination of both drugs showed high areas of synergy on multiple DMG lines, DNA double strand breaks and significant increase in cell population at the S (p&amp;lt;0.01) and G2/M (p&amp;lt;0.05) phases. Importantly, on zebrafish xenograft tumor model, combination treatment significantly (p&amp;lt;0.001) inhibited tumor growth in comparison to control and single treatment groups. Furthermore, the combined treatment demonstrated significant (p&amp;lt;0.01) survival benefit (median survival (MS) = 62 days) on tumor-bearing nude mice models, in comparison to vehicle (MS= 44 days), Val-083 (MS= 54.5 days) and AZD1775 (MS= 47 days) treatment groups. CONCLUSION Val-083 in combination with AZD1775 demonstrate promising efficacy in DMG preclinical models, providing a strong rationale for positioning these arms for clinical testing.

Plant-derived extracellular nanovesicles: a promising biomedical approach for effective targeting of triple negative breast cancer cells.

Introduction: Triple negative breast cancer (TNBC), a highly aggressive subtype accounting for 15-20% of all breast cancer cases, faces limited treatment options often accompanied by severe side effects. In recent years, natural extracellular nanovesicles derived from plants have emerged as promising candidates for cancer therapy, given their safety profile marked by non-immunogenicity and absence of inflammatory responses. Nevertheless, the potential anti-cancer effects of Citrus limon L.-derived extracellular nanovesicles (CLENs) for breast cancer treatment is still unexplored. Methods: In this study, we investigated the anti-cancer effects of CLENs on two TNBC cell lines (4T1 and HCC-1806 cells) under growth conditions in 2D and 3D culture environments. The cellular uptake efficiency of CLENs and their internalization mechanism were evaluated in both cells using confocal microscopy. Thereafter, we assessed the effect of different concentrations of CLENs on cell viability over time using a dual approach of Calcein-AM PI live-dead assay and CellTiter-Glo bioluminescence assay. We also examined the influence of CLENs on the migratory and evasion abilities of TNBC cells through wound healing and 3D Matrigel drop evasion assays. Furthermore, Western blot analysis was employed to investigate the effects of CLENs on the phosphorylation levels of phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), and extracellular signal- regulated kinase (ERK) expression. Results: We found that CLENs were internalized by the cells via endocytosis, leading to decreased cell viability, in a dose- and time-dependent manner. Additionally, the migration and evasion abilities of TNBC cells were significantly inhibited under exposed to 40 and 80μg/mL CLENs. Furthermore, down-regulated expression levels of phosphorylated phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), and extracellular signal-regulated kinase (ERK), suggesting that the inhibition of cancer cell proliferation, migration, and evasion is driven by the inhibition of the PI3K/AKT and MAPK/ERK signaling pathways. Discussion: Overall, our results demonstrate the anti-tumor efficiency of CLENs against TNBC cells, highlighting their potential as promising natural anti-cancer agents for clinical applications in cancer treatment.

Gene silencing in the aedine cell lines C6/36 and U4.4 using long double-stranded RNA

BackgroundRNA interference (RNAi) is a target-specific gene silencing method that can be used to determine gene functions and investigate host–pathogen interactions, as well as facilitating the development of ecofriendly pesticides. Commercially available transfection reagents (TRs) can improve the efficacy of RNAi. However, we currently lack a product and protocol for the transfection of insect cell lines with long double-stranded RNA (dsRNA).MethodsWe used agarose gel electrophoresis to determine the capacity of eight TRs to form complexes with long dsRNA. A CellTiter-Glo assay was then used to assess the cytotoxicity of the resulting lipoplexes. We also measured the cellular uptake of dsRNA by fluorescence microscopy using the fluorophore Cy3 as a label. Finally, we analyzed the TRs based on their transfection efficacy and compared the RNAi responses of Aedes albopictus C6/36 and U4.4 cells by knocking down an mCherry reporter Semliki Forest virus in both cell lines.ResultsThe TRs from Biontex (K4, Metafectene Pro, and Metafectene SI+) showed the best complexing capacity and the lowest dsRNA:TR ratio needed for complete complex formation. Only HiPerFect was unable to complex the dsRNA completely, even at a ratio of 1:9. Most of the complexes containing mCherry-dsRNA were nontoxic at 2 ng/µL, but Lipofectamine 2000 was toxic at 1 ng/µL in U4.4 cells and at 2 ng/µL in C6/36 cells. The transfection of U4.4 cells with mCherry-dsRNA/TR complexes achieved significant knockdown of the virus reporter. Comparison of the RNAi response in C6/36 and U4.4 cells suggested that C6/36 cells lack the antiviral RNAi response because there was no significant knockdown of the virus reporter in any of the treatments.ConclusionsC6/36 cells have an impaired RNAi response as previously reported. This investigation provides valuable information for future RNAi experiments by showing how to mitigate the adverse effects attributed to TRs. This will facilitate the judicious selection of TRs and transfection conditions conducive to RNAi research in mosquitoes.Graphical

Abstract B026: Screening non-small cell lung cancer patient-derived organoids with epigenetic probes reveals PRMT5 as an oncogenic target

Abstract Lung cancer is the leading cause of cancer-related mortality. Detection of drug actionable genetic alterations has made the standard systemic therapy to a more personalized one including targeted therapy and immune checkpoint blockade. Despite the initial response, majority of patients develop resistance to treatment. Therefore, understanding the mechanisms of resistance as well as discovering novel cancer targets is necessary. Resistance to therapies can be associated with an existing clone of tumor cells with genetic alteration, or the emergence of cells with epigenetic changes overcoming the treatment-induced stress. Therefore, investigating the epigenetic aberrations that occur in tumor cells may reveal novel targetable markers that can be of great clinical significance. Methods: Organoid models established from non-small cell lung cancer (NSCLC) patient surgical resections and pleural effusion were dissociated into single cells and plated in matrigel-coated 384-well plate. A panel of 32 NSCLC organoid models were treated with a library of 41 epigenetic probes (1uM) and a DMSO control over a period of 8 days. Cell titre glo assay was performed to measure cell survival. Results: Arginine methyl transferase protein 5 (PRMT5) inhibited the cell growth of large proportion of the NSCLC organoid models. LLY-283 showed the most significant effect, with 50% of all organoid models (16/32) treated with LLY283 showing ≥50% reduction in cell viability. Further testing with multiple concentrations of several PRMT5 inhibitors revealed models with differential responses to PRMT5 inhibition. To investigate the differential gene expression changes induced by PRMT5 inhibition, we performed RNA-sequencing on three PRMT5 inhibitor sensitive and three resistant organoid models. Ongoing analyses aim at identifying differentially expressed genes in sensitive and resistant models in response to PRMT5 inhibition, and pathway enrichment analysis to determine the differential mechanisms of response to PRMT5 inhibition. Conclusion: Epigenetic drug screening on a large cohort of NSCLC organoid models reveals PRMT5 as potential novel therapeutic target in NSCLC. Further correlative analysis with transcriptomic changes induced by the PRMT5 inhibitors may reveal biomarkers of response. Citation Format: Khadija Jafarova, Quan Li, Nikolina Radulovich, Geoffrey Liu, Ming S Tsao. Screening non-small cell lung cancer patient-derived organoids with epigenetic probes reveals PRMT5 as an oncogenic target [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr B026.

In silico design of novel multitarget small molecule inhibitors to treat PTEN-mutant endometrial carcinoma.

e15119 Background: Previously we described triple CDK4/6-CDK9 inhibitor, LCI133 for the treatment of endometrial carcinoma (EC). We used in silico modeling to optimize LCI133’s physicochemical properties to increase PI3K p110α potency/ADME to better target epithelial-derived cancers, resulting in nanomolar potent LCI139. We characterized LCI139’s in vitro potency, target specificity, activity in in vitro EC models, safety in normal cell lines. Methods: LCI139 + analogs were designed using computational chemistry based on X-ray crystal structures of each target protein + validated chemistry using nuclear magnetic resonance + high-resolution mass spectrometry. Specific target inhibition was assessed by cell-free kinase hotspot/lipid kinase assay + selectivity profile. LCI139 (0.001-10μM) was screened against EC cell lines AN3CA, RL95-2, Ishikawa, KLE, HEC-1-A and -B for 48 hours; IC50 values determined by CellTiter-Glo Assay. EC cells were treated with LCI139 or single agent control for 24 hours + stained with Annexin V/7-AAD to assess apoptosis. Representative PTEN wildtype (HEC-1A) + mutant (AN3CA) EC cell lines were chosen for mechanistic studies + treated 6 to 24 hours with multitarget or single agent inhibitor. Cells were stained with Vybrant DyeCycle Violet to determine cell cycle arrest by cytometer. Cellular lysates were prepared for Western blot (WB). Results: LCI139’s has a molecular weight of 502.57Da + is a highly potent PI3Kα-CDK4/6-CDK9 inhibitor by cell-free kinase assays: 0.070µM (PI3Kα), 0.461µM (PI3Kγ), 0.214µM (PI3Kδ), 0.0015µM (CDK4), 0.0036µM (CDK6), 0.000039µM (CDK9). KINOMEscan revealed a favorable S(35) selectivity score of 0.221 screened against 403 non-mutant kinases. PTEN mutant AN3CA (IC50 216.0nM), RL95-2 (IC50 22.8nM), Ishikawa (IC50 2.5nM) had nanomolar LCI139 IC50 values. PTEN-wild type cell lines were insensitive up to 10μM; confirmed by dose-dependent apoptosis + colony-forming assays. WB revealed LCI139 treatment ablated MCL-1 expression, decreased phosphorylation of AKT, Rb, Rpb1 (Ser2), induced significant amounts of cPARP in PTEN mutant AN3CA. In PTEN-wildtype HEC1A WB, dose-dependent expression of pAKT in PTEN siRNA was noted. LCI139 generated heterogenous cell line specific effects on cell cycle progression + arrest. LCI139 displayed favorable toxicity against normal human kidney cells (HEK-293) compared to single agent controls. Conclusions: Triple PI3K-CDK4/6-CDK9 inhibitor, LCI139, is nanomolar potent against PTEN mutant EC cell lines + displays decreased toxicity compared with CDK9 inhibitor reference compounds, AZD4573 + flavopiridol. Our results merit mechanistic dissection of PTEN interaction with PI3K + CDK9 signaling pathways, cell cycle machinery, CDK9-mediated transcriptional control. These data support extensive in vivo potency, toxicity, PK/PD studies to assess LCI139’s clinical utility in treating EC.

Effect of RGT-61159 on inhibition of oncogene c-MYB synthesis and tumor growth inhibition in a broad range of ACC PDX models, at well tolerated doses in rodents and non-human primates.

6107 Background: RGT-61159 is a first in-class oral inhibitor of the oncogenic transcription factor c-MYB via selective alteration of its RNA splicing machinery. RGT-61159 selectively induces the inclusion of the cryptic “poison” exon into the c-MYB RNA transcripts, resulting in the robust elimination of c-MYB canonical mRNA transcript and consequently of its protein in cells. Overactivation of the c-MYB oncogene, primarily due to chromosome rearrangements, is a hallmark of adenoid cystic carcinoma. (ACC). ACC is a rare and aggressive type of cancer for which effective treatment does not exist. By inhibiting oncogenic MYB protein production, RGT-61159 has the potential to efficiently and selectively inhibit proliferation or induce cell death of cancer cells overexpressing MYB protein. Methods: RGT-61159 cell killing activity was measured against a broad panel of cancer cell lines in a CellTiter-Glo assay. MYB RNA and MYB protein levels were assessed after drug treatment by RT-qPCR and JESS assay respectively. Anti-tumor activity of RGT-61159 as single agent or in combination was evaluated in a panel of ACC PDX mouse models harboring different molecular alterations in c-MYB, including ACCX6, ACCX11, ACCx5M1 and ST105B2. Results: Here, we showed that RGT-61159 has potent cancer cell killing activity (EC50 – 100nM -200nM) against a large panel of cancer cell lines overexpressing c-MYB, while sparing normal cells. Robust c-MYB RNA and c-MYB protein depletion (&gt;80%) was observed in treated cells confirming RGT-61159 on-target cell killing effect. In addition, RGT-61159 single agent showed a remarkable anti-tumor activity (up to 90% TGI) at tolerated doses in the four ACC PDX models evaluated: ACCX6, ACCx11, ACCx5M1 and STB105B2. Importantly, we confirmed that RGT-61159 anti-tumor activity correlated with c-MYB target modulation. RGT-61159 efficacious doses reduced c-MYB transcript and c-MYB protein levels (by &gt;80%) in all ACC PDx models evaluated. In addition, RNAseq analysis of ACC tumor after treatment showed that RGT-61159 drug treatment reversed the published ACC overexpression gene signature. Notably, the optimal RGT-61159 regimen was well tolerated, as assessed by changes in animal body weight and clinical signs in rodents and non-human primate. Finally, we showed that the combination of RGT-M001, an analog of RGT-61159, with the NOTCH Inhibitor AL-101 resulted in significant tumor regression at well tolerated doses. Conclusions: Altogether, these data demonstrated that RGT-61159 efficiently and safely targets the undruggable oncogenic transcription factor c-MYB. Down-regulation of c-MYB by the RGT-61159 RNA-targeting small molecule is a very promising therapeutic strategy to treat ACC and other cancers driven by c-MYB dysregulation.

Tumor-matched and unmatched cancer associated fibroblasts exhibit differential effect on proliferation and FMOD and MMP9 gene expression in head and neck squamous cell carcinoma cells when cocultured in spheroids

BackgroundCancer-associated fibroblasts (CAFs) are the major cellular component of the tumor microenvironment and are known to affect tumor growth and response to various treatments. This study was undertaken to investigate the crosstalk between tumor-matched or unmatched CAFs and head and neck squamous cell carcinoma (HNSCC) cells regarding tumor growth and treatment response.MethodsThree HNSCC cell lines (LK0412, LK0902 and LK0923), were cocultured in 2D or in 3D with their tumor-matched CAFs, site matched CAFs from other tumors or normal oral fibroblasts (NOFs). Cell proliferation was assessed as the amount of Ki67 positive cells/ spheroid area in formalin-fixed- paraffin-embedded 3D spheroids stained with Ki67 antibody. Viability after seven days of cisplatin treatment was measured with CellTiter-Glo 3D Viability Assay. The mRNA expression of CAF-associated markers (ACTA2, COL1A2, FAP, PDGFRα, PDGFRβ, PDPN, POSTN and S100A4) in CAFs before and after coculture with tumor cells as well as mRNA expression of CAF-induced genes (MMP1, MMP9 and FMOD) in tumor cells separated from CAFs after co-culture was measured with RT-qPCR. The expression of selected protein biomarkers was validated with immunohistochemistry based on previous mRNA expression results.ResultsThe proliferation of the LK0412 and LK0902 tumor spheroids varied significantly when cocultured with different CAFs and NOFs as shown by Ki-67 positive cells. RT‒qPCR analysis revealed different molecular profile of the analyzed HNSCC-derived CAFs concerning the expression of CAF-associated markers. The interaction between CAFs and HNSCC cells was more pronounced after coculture with unmatched CAFs as shown by changes in mRNA expression pattern of CAF-specific markers. Additionally, the unmatched CAFs significantly upregulated the mRNA expression of MMP1, MMP9 and FMOD in tumor cells compared to tumor-matched CAFs.ConclusionOur results indicate that tumor-matched CAFs are unique for each tumor and affect the proliferation and the gene/protein expression of tumor cells in a distinct manner. The interaction between tumor unmatched CAFs and HNSCC cells in the tumor spheroids is associated with significant changes in the mRNA expression of CAF-specific markers and significant increases in FMOD and MMP9 in tumor cells compared to when cocultured with tumor-matched CAFs. Taken together, our results show how important the selection of CAFs is to get a reliable in vitro model that mimics the patients’ tumor.

Efficacy and Safety of Asparagusic Acid against Echinococcus multilocularis In Vitro and in a Murine Infection Model.

Alveolar echinococcosis (AE) stands as a perilous zoonotic affliction caused by the larvae of Echinococcus multilocularis. There is an imperative need to explore novel therapeutic agents or lead compounds for the treatment of AE. Asparagusic acid, characterized by its low toxicity and possessing antimicrobial, antioxidant, and anti-parasitic attributes, emerges as a promising candidate. The aim of this study was to investigate the in vivo and in vitro efficacy of asparagusic acid against E. multilocularis. Morphological observations, scanning electron microscopy, ROS assays, mitochondrial membrane potential assays, and Western blot were used to evaluate the in vitro effects of asparagusic acid on protoscoleces. The effects of asparagusic acid on vesicles were assessed via PGI release, γ-GGT release, and transmission electron microscopy observations. CellTiter-Glo assays, Caspase3 activity assays, flow cytometry, and Western blot were used for an evaluation of the effect of asparaginic acid on the proliferation and apoptosis of germinal cells. The in vivo efficacy of asparagusic acid was evaluated in a murine AE model. Asparagusic acid exhibited a pronounced killing effect on the protoscoleces post-treatment. Following an intervention with asparagusic acid, there was an increase in ROS levels and a decline in mitochondrial membrane potential in the protoscolex. Moreover, asparagusic acid treatment resulted in the upregulation of PGI and γ-GGT release in metacestode vesicles, concomitant with the inhibition of germinal cell viability. Furthermore, asparagusic acid led to an enhanced relative expression of Caspase3 in the culture supernatant of both the protoscoleces and germinal cells, accompanied by an increase in the proportion of apoptotic germinal cells. Notably, asparagusic acid induced an augmentation in Bax and Caspase3 protein expression while reducing Bcl2 protein expression in both the protoscoleces and germinal cells. In vitro cytotoxicity assessments demonstrated the low toxicity of asparagusic acid towards normal human hepatocytes and HFF cells. Additionally, in vivo experiments revealed that asparagusic acid administration at doses of 10 mg/kg and 40 mg/kg significantly reduced metacestode wet weight. A histopathological analysis displayed the disruption of the germinal layer structure within lesions post-asparagusic acid treatment, alongside the preservation of laminated layer structures. Transmission electron microscopy further revealed mitochondrial swelling and heightened cell necrosis subsequent to the asparagusic acid treatment. Furthermore, asparagusic acid promoted Caspase3 and Bax protein expression while decreasing Bcl2 protein expression in perilesional tissues. Subsequently, it inhibited the expression of Ki67, MMP2, and MMP9 proteins in the perilesional tissues and curbed the activation of the PI3K/Akt signaling pathway within the lesion-host microenvironmental tissues. Asparagusic acid demonstrated a pronounced killing effect on E. multilocularis, suggesting its potential as a promising therapeutic agent for the management of AE.

The role of PPP1R3G in promoting necroptosis in ischemia reperfusion induced acute kidney injury

Recent discoveries have revealed necroptosis as a major contributor to the pathogenesis of acute kidney injury (AKI). Protein phosphatase 1 regulatory subunit 3G (PPP1R3G) has been linked to the essentiality of RIPK1-dependent apoptosis and type I necroptosis. Nonetheless, the involvement of PPP1R3G in the regulation of necroptosis during ischemia reperfusion-induced acute kidney injury (IR-AKI) has yet to be elucidated. Here, we investigated the role of PPP1R3G in the regulation of necroptosis in IR using an in vitro cellular I/R model and in vivo IRI-AKI mouse model. Primary proximal tubular cells (PTCs) from C57BL/6 and Ppp1r3g−/− mice were cultured and cell I/R was induced through hypoxia/reoxygenation. Cell viability and necroptosis were analyzed using CellTiter-Glo assay and Annexin V-Cy3/ SYTOX green staining, respectively. The expression levels of necroptosis, oxidative stress, and inflammation factors were determined by real-time PCR, western blotting, immunofluorescence staining, and ELISA. In the in vivo IRI-AKI model, bilateral renal pedicles clamping was conducted in both C57BL/6 and Ppp1r3g−/− mice. The kidney injury and function were evaluated by plasma creatine, BUN, and KIM-1 levels and GFR values, respectively. Kidney morphological evidence of injury was assessed by PAS staining and cell death by immunofluorescent staining. We found that knockout of PPP1R3G in the primary tubular cells significantly preserved cell viability and attenuated tubular cell death. This protective effect was associated with the reduced expression and phosphorylation of necroptosis factors (RIP1, RIP3, and MLKL), and inflammatory factors (IL-6, IL-10 and TNF-α) in I/R injury cells. Deletion of PPP1R3G attenuated the I/R induced kidney injury indicated by 54% decrease in the plasma creatine (2.28±0.12mg/dL vs. 1.09±0.07mg/dL, p&lt;0.0001, n=7) and 45% higher GFR values than WT mice at day 3 after reperfusion. Histology showed less diffuse renal tubular necrosis and casts comprising necrotic cells and debris in Ppp1r3g−/− mice, as well as 60% less cell death compared to WT mice. Moreover, the application of chemical compounds to prevent inhibitory phosphorylation of RIPK1 significantly reinstated cell death in Ppp1r3g−/− cells. In conclusion, our findings demonstrate, for the first time, that Ppp1r3g-mediated necroptosis significantly promotes IRI-AKI. Therefore, targeting Ppp1r3g to reduce necroptosis in the kidney holds promising potential for significant clinical benefits. National Institutes of Health Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, FL. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.