Cell Line-based Models Research Articles

Cell line-based in vitro models of normal and chronic bronchitis-like airway mucosa to study the toxic potential of aerosolized palladium nanoparticles.

Physiologically relevant cell line-based models of human airway mucosa are needed to assess nanoparticle-mediated pulmonary toxicity for any xenbiotics expsoure study. Palladium nanoparticles (Pd-NP) originating from catalytic converters in vehicles pose health risks. We aimed to develop in vitro airway models to assess the toxic potential of Pd-NP in normal (Non-CB) and chronic bronchitis-like (CB-like) mucosa models. Bronchial mucosa models were developed using Epithelial cells (16HBE: apical side) co-cultured with fibroblast (basal side) at an air-liquid interface. Furthermore, both Non-CB and CB-like (IL-13 treatment) models with increased numbers of goblet cells were used. The models were exposed to 3 different doses of aerosolized Pd-NP (0.2, 0.3, and 6 μg/cm2) using XposeALI® and clean air as a control. After 24 h of incubation, the expression of inflammatory (IL6, CXCL8, TNFα, and NFKB), oxidative stress (HMOX1, SOD3, GPx, and GSTA1), and tissue injury/repair (MMP9/TIMP1) markers was assessed using qRT-PCR. The secretion of CXCL-8 and the expression of a tissue injury/repair marker (MMP-9) were measured via ELISA. Significantly (p < 0.05) increased expressions of CXCL8, IL6, and NFKB were observed at the highest dose of Pd-NP in CB-like models. However, in Non-CB mucosa models, a maximum effect on TNFα and NFKB expression was observed at a medium Pd-NP dose. In Non-CB mucosa models, SOD3 showed a clear dose-dependent response to Pd-NP exposure, while GSTA1 expression was significantly increased (p < 0.05) only at the lowest dose of Pd-NP. The secretion of CXCL-8 increased in a dose-dependent manner in the Non-CB mucosa models following exposure to Pd-NP. In CB-like models, exposure to high concentrations of Pd-NP significantly increased the release of MMP-9 compared to that in other exposure groups. The combination of our Non-CB and CB-like mucosa models with the XposeALI® system for aerosolized nanoparticle exposure closely mimics in vivo lung environments and cell-particle interactions. Results from these models, utilizing accessible cell lines, will maximize the reliability of in vitro findings in human health risk assessment.

Evaluation of lipopolymer as therapeutic siRNA delivery agents in non-malignant and malignant primary cells.

e15189 Background: Targeting leukemia-driving oncogenes via short interfering RNA (siRNA) offers an alternative approach to leukemia treatment that can overcome the limitations of current therapies. Low molecular weight polyethyleneimine grafted with lipids (lipopolymers) have emerged as promising carriers for siRNA delivery to leukemia cells. Lipopolymers harboring select lipids were recently shown to downregulate target oncogene leading to significant anti-leukemic activity in both in vitro and in vivo cell line-based leukemia models. The goal of this study was to evaluate these lipopolymers in (i) PBMCs obtained from healthy donors to determine the potential impact on non-malignant cells, and (ii) primary leukemia patient cells to assess therapeutic efficacy. Methods: Target gene levels were determined by RT-qPCR and the effect of treatment on progenitor cells was assessed by measuring changes in colony forming ability. Results: At day 1 post-treatment, no changes in FLT3 mRNA levels were observed in all 6 PBMC samples with the 2 candidate lipopolymers (LeuFectB and LeuFectC) tested. Among 11 PBMC samples evaluated at day 2, only one sample showed a significant reduction in oncogene transcript levels on treatment with LeuFectB. The impact of lipopolymer/siRNA complex treatment on progenitor cells in the PBMC population was then assessed. Of the 7 PBMC samples tested, significant reduction in colony numbers was observed in one sample with LeuFectB and two samples with LeuFectC. On an average, the lipopolymer/siRNA complexes were well tolerated by normal healthy cells as changes observed in oncogene expression and colony forming ability were not consistent across the whole pool. Primary acute lymphoblastic leukemia (ALL) patient cells treated with complexes targeting STAT5A showed marked reduction in STAT5A transcript levels in 4 out of 7 samples with both the lipopolymers tested. The subsequent impact of STAT5A downregulation on the clonogenicity of leukemia stem cells was observed in the significant decrease in colony numbers seen in 3 samples (out of 8) with LeuFects. Additionally, combined downregulation of STAT5A and BCR-ABL genes in BCR-ABL+ ALL patient samples led to a notable decrease in cell proliferation and viability. Moreover,2 out of 3 acute myeloid leukemia (AML) patient samples harboring the FLT3-ITD mutation showed significant retardation in their colony forming ability on treatment with FLT3-targeting siRNA complexes. Collectively, the ALL and AML primary samples demonstrated promising preliminary results, suggesting a therapeutic effect on the stem cell population which is critical for mitigating relapse or prolonging remission. Conclusions: These findings provide further proof-of-concept for clinical translation of lipopolymer mediated siRNA therapy of leukemia, showing relative safety and selectivity of these lipopolymer/siRNA complexes.

Abstract 6902: Development of a stable luciferase expressing PDX-derived cell line for translational in vitro and in vivo testing

Abstract Despite much effort invested in developing novel cancer therapies, more than 90% of clinical studies fail due to toxicity or lack of efficacy in patients. This can mainly be ascribed to lack of relevant and translational preclinical models. A common model used in preclinical studies is the xenograft model using immortalized cancer cells. Cell line-based models are cost efficient and can be genetically manipulated but are often criticized for lacking translational value. A murine model with higher clinical relevance is the patient derived xenografts (PDX) model established by implanting patients’ tumor tissue onto immunodeficient mice. Knowledge of patient therapy response, mutational status and tumor heterogeneity makes it a relevant model. However, PDX models are costly, not applicable for in vitro assays or subjective to genetic manipulation. To more closely mimic in vivo tumors we have established a PDX-derived cell line (PDXc) and characterized it extensively in a head-to-head comparison to the parental PDX model. Cells were isolated from a subcutaneous (SC) glioblastoma (GBM) PDX tumor (ST146), processed into single cells and cultivated in vitro. Once the PDXc were stable over several passages the cells were re-implanted into mice. Tumor take and growth rate were evaluated against the parental PDX model and common characteristics of the model such as EFGR and Vimentin expression were determined by IHC. We furthermore generated a stable Luciferase expressing PDXc using 3rd generation lentiviral particles and implanted the cells in an intracranial (IC) model of GBM. Tumor growth was evaluated using bioluminescence imaging (BLI) and MRI. Upon multiple passages and freeze cycles the cell line (ST146c) exhibited a stable in vitro doubling time (2.6 ± 0.2 days) with a morphology like other GBM cell lines with formation of neurospheres. STR analysis confirmed a genetic identical profile to ST146. ST146c implanted into mice had similar tumor take and growth rates to the parental PDX when injected IC (&amp;gt;90%, Td=3 d) and SC (&amp;gt;75%, Td=6 d). We also showed that ST146c had more homogeneous tumor growth. Ex vivo analysis showed similar expressions of EGFR (-), Vimentin (+++) and Ki67 (++) between the models. The BLI signal obtained from luciferase expressing ST146c implanted orthotopically was correlated to tumor volume obtained by MRI. We developed a PDX cell line that preserved critical in vitro and in vivo characteristics of the PDX model such as doubling time, tumor take rate and marker expression making it feasible to use the PDXc model in future preclinical studies. This will allow in vitro screens with patient derived tumor cells. Furthermore, the expression of luciferase in the PDXc enables intracranial and metastatic implantation with tumor monitoring using BLI. This platform consisting of in vitro and in vivo PDX models could be used as a predictive translational platform for testing new cancer therapies. Citation Format: Sigrid Cold, Rikke N. Bøge, Emma Papin, Ida T. Michler, Lotte K. Kristensen, Trine B. Engel, Andreas Kjaer, Carsten H. Nielsen, Sebastian Gnosa. Development of a stable luciferase expressing PDX-derived cell line for translational in vitro and in vivo testing [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 6902.

Abstract 6991: Transcriptomic profiling of human and mouse models highlights YAP pathway hyperactivation as the underlying mechanism of the biological and clinical aggressiveness of Numb-defective bladder cancer

Abstract In this study, we identify a previously uncharacterized role for the tumor suppressor, Numb, in bladder tumorigenesis, defining new predictive biomarkers and potentially actionable targets for the treatment of non-muscle-invasive bladder cancers. We conducted a comprehensive IHC analysis of Numb expression leveraging two retrospective longitudinal cohorts comprising 356 post-cystectomy muscle-invasive bladder cancer (MIBC) patients and 77 high-grade non-muscle-invasive (NMIBC) patients with transurethral resections. We found that Numb expression is frequently deregulated in the tumor compared to the adjacent normal urothelium, with NumbLow status correlating with poorer prognosis both in MIBC, associated with advanced stage at diagnosis, vascular invasion, and worse overall survival, and in NMIBC, where a NumbLow status associates with a higher rate of progression to life-threatening MIBC disease. In a transgenic mouse model with targeted deletion of the Numb gene in the basal layer of the bladder mucosa, we observed that loss of Numb per se is sufficient to drive malignant transformation of the normal urothelium and accelerates tumorigenesis in carcinogen-induced models. Integrative transcriptomic analysis of human and mouse Numb-deficient BC models revealed consistent dysregulation of the YAP1/TAZ1 inhibitory Hippo pathway, identifying YAP1 transcriptional hyperactivation as the most distinguishing trait downstream of NUMB loss. Through genetic and pharmacological functional inhibition studies in relevant mouse and human BC cell line-based models, we provide proof-of-evidence that interfering with YAP pathway activation at multiple upstream levels of the Hippo cascade reverts the aggressive Numb loss-associated tumor phenotypes, in particular growth and invasive/migratory potential, thereby highlighting the YAP pathway as a potential therapeutical vulnerability for the treatment of clinically aggressive Numb-deficient human BC. We also identified a gene signature of early BC depending on loss of Numb that we extensively validated for its potential as a predictor of NMIBC to MIBC progression, arguing for its clinical application as a biomarker for NIMBC patient stratification for targeted anti-YAP signaling treatment to prevent MIBC transition. In summary, our study identifies a previously uncharacterized role of Numb in bladder cancer progression, highlighting its potential as a predictive biomarker of NMIBC to MIBC transition and response to targeted therapies, thereby advancing a framework for precision oncology for NMIBC patients at high risk of progression to life-threatening MIBC disease. Citation Format: Francesco Antonio Tucci, Rosa Pennisi, Maria Grazia Filippone, Roberta Bonfanti, Francesco Romeo, Damiano Rigiracciolo, Stefano Freddi, Francesca Sanguedolce, Giuseppe Renne, Giancarlo Pruneri, Gianluca Vago, Daniela Tosoni, Salvatore Pece. Transcriptomic profiling of human and mouse models highlights YAP pathway hyperactivation as the underlying mechanism of the biological and clinical aggressiveness of Numb-defective bladder cancer [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 6991.

Abstract A069: Study of MUC16/ERBB axis in pancreatic cancer

Abstract Background: Pancreatic cancer is the third leading cause of cancer-related deaths due to its poor prognosis and highly malignant nature. The altered expression of glycans and glycoproteins is associated with malignancy. MUC16 (also known as CA125) is a member of mucin family of glycoproteins known to line epithelial cells for protection and lubrication and is overexpressed in several cancer types, including pancreatic cancer, often linked with enhanced disease progression, metastasis, and reduced patient survival. Significance: Circulating levels of MUC16/CA125 has been used as a biomarker to monitor adenocarcinoma for decades. However, the functional role of CA125/MUC16 is yet to be elucidated due to a lack of studies on its large, heavily glycosylated structure and unknown functional domains. We present evidence that in addition to serving as a biomarker, circulating MUC16 has pro-tumorigenic activities. Hypothesis: Based on recent findings, we hypothesize that isoforms of MUC16 have high avidity for ErbB receptor and integrin complexes, with concomitant activation of downstream signaling cascades that include Akt and FAK, respectively. These result in the increased tumorigenic potential of pancreatic cancer cells in an autocrine manner. Experimental Design: There are four members of ErbB receptors; where receptor dimerization is a function of ligand binding and results in distinct downstream oncogenic signaling cascades. We evaluated the binding of MUC16 to different ErbB receptors, and its capacity to activate downstream signaling pathways using pancreatic cell line models that have different combinations of knock out/down of each ErbB receptor. We evaluated the global changes in the phosphorylation of oncogenic signaling molecules due to MUC16 binding using Reverse Phase Protein Array (RPPA). Results: We found that MUC16 activates Erbb4 (Y1162) along with other members of ErbB receptor family, where glycosylation of MUC16 is crucial for its biological activity. MUC16 enhanced oncogenic signaling through the phosphorylation of various downstream molecules and activated PI3K, RTK, MAPK, and DNA repair pathways. Our future directions include elucidating the molecular mechanism by which MUC16 activates the oncogenic signaling cascades via binding to ErbB receptors using our pancreatic cell line-based models. Conclusions: Understanding the biological activity of MUC16 and its cleaved product will further help in investigating the role of MUC16 in tumor microenvironment and at distant organ sites to influence the metastatic niche. Citation Format: Amina Baniya, Michael A. (Tony) Hollingsworth. Study of MUC16/ERBB axis in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A069.

Abstract A043: CDK8/19-regulated transcriptional reprogramming: a druggable driver of castration-resistant prostate cancer

Abstract Androgen deprivation therapy (ADT) is the mainstay of prostate cancer (PCa) treatment. However, most patients with aggressive PCa become resistant to ADT and develop castration-resistant prostate cancer (CRPC). Newer androgen receptor (AR)-targeting CRPC treatments extend survival by only a few months, and metastatic CRPC (mCRPC) remains an incurable disease. Multiple mechanisms of ADT resistance have been identified, among which non-genetic (transcriptional) mechanisms are prominent, due to the high transcriptomic plasticity of PCa and the role of tumor microenvironment (TME) as a determinant of ADT resistance. PCa progression involves changes in the expression of CDK8 and CDK19, enzymatic components of the cyclin-dependent kinase module (CKM), associated with the transcriptional Mediator complex and implicated in transcriptional reprogramming and immune surveillance. We have investigated the roles of CDK8/19 Mediator kinases in CRPC, through bioinformatic analysis of primary PCa and mCRPC and by analyzing the effects of genetic and pharmacological inhibition of CDK8 and CDK19 on tumor growth and gene expression. CDK8 and CDK19 were found to be differentially regulated by androgen, which downregulates CDK8 and upregulates CDK19. Accordingly, CDK8 is decreased and CDK19 increased in primary PCa, where CDK19 is expressed higher than in any other tissues or tumors. However, both CDK19 and CDK8, as well as the other components of the CKM, are upregulated in mCRPC, concordantly with the changes in AR-mediated transcriptional signaling. Selective Mediator kinase inhibitors did not suppress PCa models driven by canonical AR signaling but inhibited in vivo growth of cell line-based and patient-derived xenograft (PDX) models of CRPC. Genetic inactivation of CDK8 and CDK19 suppressed 22Rv1 CRPC tumors in surgically or chemically castrated (but not intact) male NSG mice, whereas the expression of CDK19 or CDK8 reversed this phenotype. Transcriptomic analysis revealed that Mediator kinase inhibition exerted the strongest effects on gene expression in tumors growing in castrated mice, increasing the transcriptomic effects of castration on most of the genes regulated by CDK8/19, while decreasing its effects on some of the genes implicated in PCa progression. A gene signature reflecting Mediator kinase activity in CRPC xenografts correlated with shorter overall survival among mCRPC patients. Systemic treatment with a CDK8/19 inhibitor also affected stromal gene expression; many of these effects were reproduced by Mediator kinase mutagenesis in tumor cells alone, suggesting that Mediator kinases of tumor cells are involved in shaping the TME. Prolonged (up to 300 days) CDK8/19 inhibition induced not only growth inhibition but also shrinkage of CRPC tumors in nude mice (which contain NK cells that are stimulated by CDK8/19 inhibition) and even produced cures in 18-27% of animals. These results warrant the exploration of CDK8/19 Mediator kinase inhibitors for the treatment of the presently incurable CRPC. Citation Format: Jing Li, Thomas Hilimire, Yueying Liu, Lili Wang, Jiaxin Liang, Balazs Gyorffy, Vitali Sikitzhytski, Hao Ji, Li Zhang, Chen Cheng, Xiaokai Ding, Kendall Kerr, Charles Dowling, Gary Schools, Chang-Uk Lim, Eugenia Broude, George Wilding, Michael Lilly, Igor Roninson, Mengqian Chen. CDK8/19-regulated transcriptional reprogramming: a druggable driver of castration-resistant prostate cancer [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 A043.

FF-10850, a Novel Liposomal Topotecan Achieves Superior Antitumor Activity via Macrophage- and Ammonia-Mediated Payload Release in the Tumor Microenvironment.

Topotecan, an approved treatment for refractory or recurrent ovarian cancer, has clinical limitations such as rapid clearance and hematologic toxicity. To overcome these limitations and maximize clinical benefit, we designed FF-10850, a dihydrosphingomyelin-based liposomal topotecan. FF-10850 demonstrated superior antitumor activity to topotecan in ovarian cancer cell line-based xenograft models, as well as in a clinically relevant DF181 platinum-refractory ovarian cancer patient-derived xenograft model. The safety profile was also improved with mitigation of hematologic toxicity. The improved antitumor activity and safety profile are achieved via its preferential accumulation and payload release triggered in the tumor microenvironment. Our data indicate that tumor-associated macrophages internalize FF-10850, resulting in complete payload release. The release mechanism also appears to be mediated by high ammonia concentration resulting from glutaminolysis, which is activated by tumor metabolic reprogramming. In ammonia-rich conditions, FF-10850 released payload more rapidly and to a greater extent than liposomal doxorubicin, a currently approved treatment for ovarian cancer. FF-10850 significantly enhanced antitumor activity in combination with carboplatin or PARP inhibitor without detrimental effects on body weight in murine xenograft models, and demonstrated synergistic antitumor activity combined with anti-PD-1 antibody with the development of tumor antigen-specific immunity. These results support phase I investigation of FF-10850 for the treatment of solid tumors including ovarian cancer (NCT04047251), and further evaluation in combination settings.

P10.23.A A PATIENT-DERIVED FUNCTIONAL GBM DRUG SCREEN OFFERS A TOOL TO PREDICT TMZ RESPONSE AND ASSESS SENSITIVITY TO CANDIDATE TREATMENTS ON A PER PATIENT BASIS

Abstract BACKGROUND Major obstacles that have impeded the development of effective new therapies for GBM include inter- and intratumoral heterogeneity, the blood-brain-barrier and use of sub-optimal cell line-based preclinical models. Taking these hurdles into account, we have set up a patient-derived GBM drug-screening platform. Molecular similarities and dissimilarities between tumors and derived cultures were investigated and the predictive power of our assay for patient response to TMZ was assessed. A large panel of GBM cells was screened for sensitivity to available oncological agents with the aim of deriving a set of drugs with favorable physicochemical properties for BBB crossing and potent activity in (a subset of) GBM cultures. Finally, we determined the success rate of performing a small-scale screen with 20 selected agents within 4 weeks post-surgery. MATERIAL AND METHODS Tissue samples as well as ultrasonic surgical aspirates (USA) were received from GBM surgeries and utilized to establish glioma stem cell (GSC) cultures. Correspondence of GSCs to parental tumors was assessed by DNA/RNA-sequencing. In vitro sensitivity to temozolomide was screened across 55 GSC cultures. Cell viability readouts were related to clinical parameters of corresponding patients. FDA-approved anticancer agents (n=107) were screened on 45 GBM cultures by dose-response testing and viability was assessed using Cell Titer-Glo. Twenty selected agents were screened on 24 fresh tumor samples within 4 weeks of receiving the tissue. RESULTS By combining both USA and tissue piece-derived dissociation protocols, culture success increased to 95%, ensuring representation of the near-complete spectrum of GBM subtypes. Tumor DNA and RNA sequences revealed strong similarities to corresponding GSC cultures although differences related to neuronal signaling, immune interactions, and cell cycle were observed. Tumor expression profiles of hallmark genes of GBM were faithfully retained in derived cell cultures. In vitro screening of TMZ on a large cohort identified 3 response categories (responders/intermediates/non-responders) for which Cox regression analysis revealed significantly different overall survival curves of corresponding patients. Screening of approved anticancer agents on 45 GBM cultures underscored the tremendous intertumoral heterogeneity in drug sensitivities. We identified 20 potent agents each effective at clinically-achievable concentrations in (a subset of) GBM cultures with favorable BBB penetration properties (CNS-MPO score). Screening of these agents on a per patient basis within 4 weeks of receiving tissue was successful in 18 out of 24 (75%) tested tumors. CONCLUSION Patient-derived functional drug screening offers a tool to predict TMZ response in GBM patients and assess tumor sensitivity to candidate treatments, either for GBM subsets or on a per patient basis.

Abstract 4558: High-throughput, high content Imaging assay for assessing solid tumor phagocytosis in 3D spheroid model

Abstract Emerging studies have demonstrated that innate immune checkpoints, regulating Tumor-associated Macrophage (TAM) phagocytic activity, play a crucial role in immune escape and survival of cancer cells. CD47-SIRPα axis is the best studied example of the “don’t eat me” signal, frequently overexpressed on cancer cell. Targeting of CD47 protein has shown impressive results in clinical trials in hematologic malignancies but remained challenging for solid tumors therapy. Therefore, tools facilitating the development of novel innate immune checkpoint inhibitors are of great interest. To address that unmet need, we established a high-throughput, 384-well-format assay for efficacy assessment of compounds inducing macrophage phagocytosis. As a model of solid tumor, we employed 3D spheroids aggregated of human cancer cell lines (A375, HCT116, MCF7, SKOV3) expressing GFP or PDX material (LXFA1647 lung adenocarcinoma, MEXF2106 melanoma) and cancer associated fibroblasts, as well as Monocyte-Derived Macrophages (MDMs) which altogether were co-aggregated to form spheroids mimicking the tumor microenvironment and immune-competence. In parallel MDMs were co-cultured with matured spheroid to emulate tumor infiltration. Both models were cultured in automation and High Content imaging compatible Akura™ 384-well plate. To evaluate our system, we targeted CD47-SIRPα axis by treatment of 3D spheroid models with αCD47 antibody (H6D12) in combination with atezolizumab (αPD-L1 antibody). Tumor viability and growth were assessed by fluorescence measurements and ATP level. Phagocytosis of fluorescently labeled tumor cells was imaged by confocal microscopy and quantified by inhouse developed analysis pipeline. Immune cell activation was evaluated by a cytokine bead array. The treatment of cell line-based 3D models with αCD47 antibody resulted in an increased number of phagocytic macrophages followed by a decrease of fluorescence and size of tumor spheroids in a dose-dependent manner. Moreover, we observed an induced secretion of TNFα, IL-6, IL-10 and IL-RA after 48h. Similarly, in PDX-based models, we observed decreased spheroid size and ATP level at day 7. Notably, αCD47 antibody-induced level of cytokines was further increased in combination with atezolizumab. To conclude, we have developed a human disease relevant, high-throughput assay for the evaluation of novel therapeutic modalities targeting phagocytosis. Due to compatibility with microscopy and most of the biochemical assays, it represents a powerful tool for clinical candidate development. Citation Format: Michal Rudnik, Özlem Yavaş Grining, Nadezhda Rotankova, Silvan Strebel, Francesca Chiovaro, Olivier Frey, Irina Agarkova, Wolfgang Moritz. High-throughput, high content Imaging assay for assessing solid tumor phagocytosis in 3D spheroid model. [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 4558.

Investigating nanoplastics toxicity using advanced stem cell-based intestinal and lung in vitro models.

Plastic particles in the nanometer range-called nanoplastics-are environmental contaminants with growing public health concern. As plastic particles are present in water, soil, air and food, human exposure via intestine and lung is unavoidable, but possible health effects are still to be elucidated. To better understand the Mode of Action of plastic particles, it is key to use experimental models that best reflect human physiology. Novel assessment methods like advanced cell models and several alternative approaches are currently used and developed in the scientific community. So far, the use of cancer cell line-based models is the standard approach regarding in vitro nanotoxicology. However, among the many advantages of the use of cancer cell lines, there are also disadvantages that might favor other approaches. In this review, we compare cell line-based models with stem cell-based in vitro models of the human intestine and lung. In the context of nanoplastics research, we highlight the advantages that come with the use of stem cells. Further, the specific challenges of testing nanoplastics in vitro are discussed. Although the use of stem cell-based models can be demanding, we conclude that, depending on the research question, stem cells in combination with advanced exposure strategies might be a more suitable approach than cancer cell lines when it comes to toxicological investigation of nanoplastics.

From the Editor’s Desk...

From the Editor’s Desk...

Insect Cell-Based Models: Cell Line Establishment and Application in Insecticide Screening and Toxicology Research.

During the past decades, research on insect cell culture has grown tremendously. Thousands of lines have been established from different species of insect orders, originating from several tissue sources. These cell lines have often been employed in insect science research. In particular, they have played important roles in pest management, where they have been used as tools to evaluate the activity and explore the toxic mechanisms of insecticide candidate compounds. This review intends to first briefly summarize the progression of insect cell line establishment. Then, several recent studies based on insect cell lines coupled with advanced technologies are introduced. These investigations revealed that insect cell lines can be exploited as novel models with unique advantages such as increased efficiency and reduced cost compared with traditional insecticide research. Most notably, the insect cell line-based models provide a global and in-depth perspective to study the toxicology mechanisms of insecticides. However, challenges and limitations still exist, especially in the connection between in vitro activity and in vivo effectiveness. Despite all this, recent advances have suggested that insect cell line-based models promote the progress and sensible application of insecticides, which benefits pest management.

DDDR-27. A PATIENT-DERIVED DRUG SCREENING PLATFORM PREDICTS RESPONSE TO TEMOZOLOMIDE AND IDENTIFIES POTENTIAL NEW TREATMENTS FOR GLIOBLASTOMA

Abstract BACKGROUND Major obstacles that have impeded the development of effective new therapies for GBM include inter- and intratumoral heterogeneity, the blood-brain-barrier and use of sub-optimal cell line-based preclinical models. Taking these hurdles into account, we have set up a patient-derived GBM drug-screening platform. We optimized protocols to improve cell culture success rate and retrospectively assessed the predictive power of our assay for patient response to TMZ. A large panel of GBM cells was screened for sensitivity to available oncological agents. Drugs of interest were selected based on favorable physicochemical properties for BBB crossing and potent activity in (a subset of) GBM cultures. Finally, we determined the success rate of performing a small-scale screen with 20 selected agents within 4 weeks of receiving tumor tissue. RESULTS By combining both CUSA and tissue piece-derived dissociation protocols, culture success increased to 95%, ensuring representation of the near-complete spectrum of GBM subtypes. Single-cell sequencing studies confirmed heterogeneity in our low-passage cell cultures. In vitro screening of TMZ on a large cohort (n = 55) identified 3 response categories (responders/intermediates/non-responders) for which Cox regression analysis revealed significantly different overall survival curves of corresponding patients. Screening of 107 FDA-approved anticancer agents on 45 GBM cultures underscored the tremendous intertumoral heterogeneity in drug sensitivities. We identified 20 potent agents each effective at clinically-achievable concentrations in (a subset of) GBM cultures and having favorable BBB penetration properties (CNS-MPO score). Screening of these agents on a per patient basis within 4 weeks of receiving tissue was successful in 18 out of 24 (75%) tested tumors. In the remaining cases the tumor cells grew very slowly and longer culture times were required. CONCLUSION Our drug screening platform offers a tool to predict TMZ response and assess sensitivity to candidate treatments, either for GBM subsets or on a per patient basis.

Bile components affect the functions and transcriptome of the rainbow trout intestinal epithelial cell line RTgutGC

The concomitant increase in cultivation of fish and decrease in supply of marine ingredients, have greatly increased the demand for new nutrient sources. This also regards so-called functional ingredients which may benefit health and welfare of the fish. In vitro cell line-based intestinal epithelial barrier models may serve as tools for narrowing down the broad range of ingredient options, to identify the most promising candidates before in vivo feeding trials are run. In vivo, differentiation of the various epithelial cells in the fish intestine, from the multipotent stem cells, takes place in the presence of a variety of substances from dietary and endogenous origin. Among these, bile salts have recently received attention as regulators of epithelial function in health and disease but have not, until now, been included in the medium when culturing fish gut epithelial cells in vitro. As bile salts are present at high levels in the chyme of the fish intestine, in particular in salmon and rainbow trout, mostly as taurocholate (>90%), their role for effects of diet ingredients on the in vitro gut cell model should be understood.With this study, we wanted to investigate whether inclusion of bile from rainbow trout or pure taurocholate in the culture media would modulate functions of the RTgutGC epithelial cells. Here, we demonstrated that the rainbow trout intestinal epithelial cell line RTgutGC responded significantly to the presence of bile components. Treatment with rainbow trout bile taken from the gall bladder (RTbile) or pure taurocholate (TC) at taurocholate concentrations of ≤0.5 mg/mL retained normal cell morphology, cell viability as in cell oxidation-reduction metabolic activity and membrane integrity, and barrier features, while high concentrations of bile salts (≥1 mg/mL) were cytotoxic to the cells. After long-term (4 days) bile treatment, transcriptome responses showed how bile salts play important roles in intestinal epithelial cell metabolism. qPCR data demonstrated that barrier function genes, brush border enzyme genes and immune genes were significantly affected. Although similar trends were seen, treatment with bile salt as a component of rainbow trout bile or pure taurocholate, induced somewhat different effects. In conclusion, this study clearly indicates that bile salts should be included in the cell medium when running in vitro studies of gut cell functions, not at least immune functions, preferably at the level of ∼0.5 mg/mL supplemented as pure taurocholate to ensure reproducibility.

Treatment of HCC with claudin-1-specific antibodies suppresses carcinogenic signaling and reprograms the tumor microenvironment

Despite recent approvals, the response to treatment and prognosis of patients with advanced hepatocellular carcinoma (HCC) remain poor. Claudin-1 (CLDN1) is a membrane protein that is expressed at tight junctions, but it can also be exposed non-junctionally, such as on the basolateral membrane of the human hepatocyte. While CLDN1 within tight junctions is well characterized, the role of non-junctional CLDN1 and its role as a therapeutic target in HCC remains unexplored. Using humanized monoclonal antibodies (mAbs) specifically targeting the extracellular loop of human non-junctional CLDN1 and a large series of patient-derived cell-based and animal model systems we aimed to investigate the role of CLDN1 as a therapeutic target for HCC. Targeting non-junctional CLDN1 markedly suppressed tumor growth and invasion in cell line-based models of HCC and patient-derived 3D exvivo models. Moreover, the robust effect on tumor growth was confirmed invivo in a large series of cell line-derived xenograft and patient-derived xenograft mouse models. Mechanistic studies, including single-cell RNA sequencing of multicellular patient HCC tumorspheres, suggested that CLDN1 regulates tumor stemness, metabolism, oncogenic signaling and perturbs the tumor immune microenvironment. Our results provide the rationale for targeting CLDN1 in HCC and pave the way for the clinical development of CLDN1-specific mAbs for the treatment of advanced HCC. Hepatocellular carcinoma (HCC) is associated with high mortality and unsatisfactory treatment options. Herein, we identified the cell surface protein Claudin-1 as a treatment target for advanced HCC. Monoclonal antibodies targeting Claudin-1 inhibit tumor growth in patient-derived exvivo and invivo models by modulating signaling, cell stemness and the tumor immune microenvironment. Given the differentiated mechanism of action, the identification of Claudin-1 as a novel therapeutic target for HCC provides an opportunity to break the plateau of limited treatment response. The results of this preclinical study pave the way for the clinical development of Claudin-1-specific antibodies for the treatment of advanced HCC. It is therefore of key impact for physicians, scientists and drug developers in the field of liver cancer and gastrointestinal oncology.

Syngeneic Mouse Orthotopic Allografts to Model Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a very complex disease characterized by a heterogeneous tumor microenvironment made up of a diverse stroma, immune cells, vessels, nerves, and extracellular matrix components. Over the years, different mouse models of PDAC have been developed to address the challenges posed by its progression, metastatic potential, and phenotypic heterogeneity. Immunocompetent mouse orthotopic allografts of PDAC have shown good promise owing to their fast and reproducible tumor progression in comparison to genetically engineered mouse models. Moreover, combined with their ability to mimic the biological features observed in autochthonous PDAC, cell line-based orthotopic allograft mouse models enable large-scale in vivo experiments. Thus, these models are widely used in preclinical studies for rapid genotype-phenotype and drug-response analyses. The aim of this protocol is to provide a reproducible and robust approach to successfully inject primary mouse PDAC cell cultures into the pancreas of syngeneic recipient mice. In addition to the technical details, important information is given that must be considered before performing these experiments.

Modulatory Contribution of Oxygenating Hydrogels and Polyhexamethylene Biguanide on the Antimicrobial Potency of Neutrophil-like Cells.

Neutrophils are a first line of host defense against infection and utilize a series of oxygen-dependent processes to eliminate pathogens. Research suggests that oxygen availability can improve anti-infective mechanisms by promoting the formation of reactive oxygen species. Also, oxygen can synergistically upregulate the antibacterial properties of certain antibiotics against bacteria by altering their metabolism and causing an increase in the antibiotic uptake of bacteria. Therefore, understanding the effects of oxygen availability, as provided via a biomaterial treatment alone or along with potent antibacterial agents, on neutrophil functions can lead us to the development of new anti-inflammatory and anti-infective approaches. However, the study of neutrophil functions in vitro is often limited by their short life span and nonreproducibility, which suggests the need for cell line-based models as a substitute for primary neutrophils. Here, we took advantage of the differentiated human leukemia-60 cell line (HL-60), as an in vitro neutrophil model, to test the effects of local oxygen and antibacterial delivery by fluorinated methacrylamide chitosan (MACF) hydrogels incorporated with polyhexamethylene biguanide (PHMB) antibacterial agent. Considering the natural modes of neutrophil actions to combat bacteria, we studied the impact of our dual functioning oxygenating-antibacterial platforms on neutrophil phagocytosis and antibacterial properties as well as the formation of neutrophil extracellular traps (NETs) and reactive oxygen species (ROS). Our results demonstrated that supplemental oxygen and antibacterial delivery from MACF-PHMB hydrogel platforms upregulated neutrophil antibacterial properties and ROS production. NET formation by neutrophils upon treatment with MACF and PHMB varied when chemical and biological stimuli were used. Overall, this study presents a model to study immune responses in vitro and lays the foundation for future studies to investigate if similar responses also occur in vivo.

Patient-Derived Xenografts of High-Grade Serous Ovarian Cancer Subtype as a Powerful Tool in Pre-Clinical Research.

(1) Background. PDX models have become the preferred tool in research laboratories seeking to improve development and pre-clinical testing of new drugs. PDXs have been shown to capture the cellular and molecular characteristics of human tumors better than simpler cell line-based models. More recently, however, hints that PDXs may change their characteristics over time have begun to emerge, emphasizing the need for comprehensive analysis of PDX evolution. (2) Methods. We established a panel of high-grade serous ovarian carcinoma (HGSOC) PDXs and developed and validated a 300-SNP signature that can be successfully utilized to assess genetic drift across PDX passages and detect PDX contamination with lymphoproliferative tissues. In addition, we performed a detailed histological characterization and functional assessment of multiple PDX passages. (3) Results. Our data show that the PDXs remain largely stable throughout propagation, with marginal genetic drift at the time of PDX initiation and adaptation to mouse host. Importantly, our PDX lines retained the major histological characteristics of the original patients' tumors even after multiple passages in mice, demonstrating a strong concordance with the clinical responses of their corresponding patients. (4) Conclusions. Our data underline the value of defined HGSOC PDXs as a pre-clinical tumor model.

The novel indomethacin derivative CZ-212-3 exerts antitumor effects on castration-resistant prostate cancer by degrading androgen receptor and its variants.

Androgen receptor (AR) serves as a main therapeutic target for prostate cancer (PCa). However, resistance to anti-androgen therapy (SAT) inevitably occurs. Indomethacin is a nonsteroidal anti-inflammatory drug that exhibits activity against prostate cancer. Recently, we designed and synthesized a series of new indomethacin derivatives (CZ compounds) via Pd (II)-catalyzed synthesis of substituted N-benzoylindole. In this study, we evaluated the antitumor effect of these novel indomethacin derivatives in castration-resistant prostate cancer (CRPC). Upon employing CCK-8 cell viability assays and colony formation assays, we found that these derivatives had high efficacy against CRPC tumor growth in vitro. Among these derivatives, CZ-212-3 exhibited the most potent efficacy against CRPC cell survival and on apoptosis induction. Mechanistically, CZ-212-3 significantly suppressed the expression of AR target gene networks by degrading AR and its variants. Consistently, CZ-212-3 significantly inhibited tumor growth in CRPC cell line-based xenograft and PDX models in vivo. Taken together, the data show that the indomethacin derivative CZ-212-3 significantly inhibited CRPC tumor growth by degrading AR and its variants and could be a promising agent for CRPC therapy.

Towards the Next Generation CAR T Cells with TEGs: In Vivo Efficacy — Toxicity Profile in Xenografts of Primary Human AML Disease and Healthy Bone Marrow

T.S. and I.J.G. contributed equally</spanBackgroundγδT cells mediate essential cancer immune surveillance by sensing transformation-dependent metabolic changes through their γδT cell receptors (TCRs). This process is independent ofMHC-restricted antigen presentation, making these innate-like receptors valuable additions to current treatment strategies. The γδTCR alone is instrumental to distinguish between healthy and leukemic stem cells. This concept led to the development of next generation CAR T cells, so-called TEGs: αβT cells Engineered to express a defined γδTCR. A particular γ9δ2TCR, isolated from “clone 5”, has been selected as the candidate for clinical testing (TEG001). A purification strategy was introduced that combined maximal interference of γδTCR chains with endogenous TCR chains with a GMP-grade anti-αβTCR-bead-based depletion strategy to obtain a pure population of engineered immune cells (Straetemans et al. Clin Can Res 2015). TEG001 cells showed a strong and broad recognition of hematological malignancies against both cell lines and primary AML in vitro and limited the tumor outgrowth in cell line-based mouse xenograft models (Marcu-Malina et al. Blood 2011, Gruender et al. Blood 2012). To further prepare clinical implementation of this novel strategy we here investigated the in vivo efficacy and toxicity profile against primary leukemic blasts and healthy hematopoietic cells, respectively.ResultsIn order to evaluate the biodistribution and safety profile of TEGs we developed patient derived xenograft (PD-X) in vivo models by establishing primary malignant AML blasts, which tested positive in an in vitro assay for recognition by TEGs, in NSG mice. In addition, healthy stem cells from human cord-blood were in parallel engrafted in a separate set of NSG mice. This allowed us to study the homing capacity, tumor-targeting efficacy and off-target toxicity of TEGs by following the outgrowth of malignant and healthy human cell fractions in the peripheral blood. Healthy hematological cellular compartments remained unharmed by TEGs, in spite of effector cell persistence for over 50 days. In contrast, AML blasts could be eliminated as measured by frequencies of blasts in peripheral blood.ConclusionWithin the limitations of humanized PD-X models, TEGs target acute myeloid leukemia but do neither interfere with engraftment of hematopoietic progenitors nor harm matured subsets of the hematopoiesis. In addition, no additional signs of off-target toxicity were observed in mice. TEGs are a promising addition to the currently available immune therapeutic strategies as they target cancer as a metabolic disorder. A GMP-compliant production procedure has now been established in order to evaluate TEG001 in a phase I open label dose escalation study to assess the safety of TEGs in patients with primary refractory or relapsed acute myeloid leukemia as well as patients with multiple myeloma. DisclosuresSebestyen:University Medical Center Utrecht: Patents & Royalties: inventor on the recognition mechanism of clone 5. Kuball:Gadeta (www.gadeta.nl): Consultancy, Equity Ownership, Patents & Royalties: on gdT cells and receptors and isolation strategies , Research Funding; Miltenyi: Research Funding.