Standard Monolayer Culture Research Articles

Primary human hepatocytes-laden scaffolds for the treatment of acute liver failure

Cell-based liver therapies based on retrieving and steadying failed metabolic function(s) for acute and chronic diseases could be a valuable substitute for liver transplants, even though they are limited by the low engraftment capability and reduced functional quality of primary human hepatocytes (PHH). In this paper we propose the use of gelatin-hyaluronic acid (Gel-HA) scaffolds seeded with PHH for the treatment of liver failure. We first optimized the composition using Gel-HA hydrogels, looking for the mechanical properties closer to the human liver and determining HepG2 cells functionality. Gel-HA scaffolds with interconnected porosity (pore size 102 μm) were prepared and used for PHH culture and evaluation of key hepatic functions. PHH cultured in Gel-HA scaffolds exhibited increased albumin and urea secretion and metabolic capacity (CYP and UGT activity levels) compared to standard monolayer cultures. The transplant of the scaffold containing PHH led to an improvement in liver function (transaminase levels, necrosis) and ameliorated damage in a mouse model of acetaminophen (APAP)-induced liver failure. The study provided a mechanistic understanding of APAP-induced liver injury and the impact of transplantation by analyzing cytokine production and oxidative stress induction to find suitable biomarkers of cell therapy effectiveness.

High-Resolution In Situ High-Content Imaging of 3D-Bioprinted Single Breast Cancer Spheroids for Advanced Quantification of Benzo(a)pyrene Carcinogen-Induced Breast Cancer Stem Cells.

Cancer stem cells (CSCs), also known as tumor-initiating cells, are critically correlated with carcinogenesis and are strongly affected by the environmental factors. Environmental carcinogens, such as benzo(a)pyrene (BaP), are associated with the overproduction of CSCs in various types of cancers, including breast cancer. In this report, we present a sophisticated 3D breast cancer spheroid model for the direct identification and quantitative determination of CSCs induced by carcinogens within intact 3D spheroids. To this end, hydrogel microconstructs containing MCF-7 breast cancer cells were bioprinted within direct-made diminutive multi-well chambers, which were utilized for the mass cultivation of spheroids and in situ detection of CSCs. We found that the breast CSCs caused by BaP-induced mutations were higher in the biomimetic MCF-7 breast cancer spheroids than that in standard 2D monolayer cultures. Precisely controlled MCF-7 cancer spheroids could be generated by serially cultivating MCF-7 cells within the printed hydrogel microconstructs, which could be further utilized for high-resolution in situ high-content 3D imaging analysis to spatially identify the emergence of CSCs at the single spheroid level. Additionally, potential therapeutic agents specific to breast CSCs were successfully evaluated to verify the effectiveness of this model. This bioengineered 3D cancer spheroid system provides a novel approach to investigating the emergence of CSC induced by a carcinogen for environmental hazard assessment in a reproducible and scalable format.

142 The phenotype of dermal fibroblasts in young vs. aged human skin: Adaptation to dermal extracellular matrix deterioration and cell autonomous responses

The dermis is largely composed of collagen-rich fibrils that form a dense extracellular matrix (ECM). Dermal fibroblasts produce and are embedded within the dermal ECM. During aging, the ECM becomes fragmented. This fragmentation is associated with deleterious alterations of fibroblast function. We have investigated the degree to which these alterations stem from adaptation to dermal ECM deterioration versus cell-autonomous age-driven responses. Primary dermal fibroblasts from young (20-30 years old, 6 females, 6 males) and aged (>80 years old, 6 females, 6 males) individuals were placed in standard monolayer culture and either harvested at 70% confluence (P1) for telomere quantitation and RNAseq transcriptome analysis or cultured through multiple passages.

Abstract B041: Mimicking tumor acidic and hypoxic microenvironment in vitro towards generation of more predictive screening platform for solid tumors

Abstract The drug discovery process in oncology relies mainly on screening and preclinical validation platforms that use human cancer cells that are grown in standard monolayer (2D) cultures. However, 2D monolayer cell culture methods poorly reflect the tumor microenvironment (TME) and the transcriptome and epigenome attributes of the cancer cells in vivo, leading to inaccurate estimate of drug efficacy in clinic. The TME of solid tumors is complex yet it consist of generic hallmarks such as hypoxia and extracellular acidosis that are common across tumor types and directly modulate gene expression and epigenome. Here we hypothesized that in vitro culture systems that recapitulate the acidic and hypoxic features of the solid TME, more accurately reflect the gene expression profile of cells in in vivo tumors, and thus serve as improved drug screening platform that reliably determine drug efficacies. Here we surveyed systematically the impact on transcriptome and epigenome hallmarks of exposure to hypoxia and acidosis on 2D and 3D cultures of A549 lung adenocarcinoma cell line as a model for solid tumor. To recapitulate naturally occurring hypoxia in vitro, A549 cells were adapted over several passages to growth in 3D. Transcriptome data derived from cells adapted to 3D, when compared to 2D and patient tumor datasets suggested that time spent in 3D increased the concordance of transcriptome profile with tumors from patients. Furthermore adaptation to 3D revealed emergence of hypoxia hallmarks when compared to 2D. To model the combined effect of hypoxia and acidosis, the 3D adapted A549 spheroids were additionally exposed to low pH conditions (6.4) for a duration of 5 days. The additional exposure to low pH led to enhanced tumor progressive phenotypes as evidenced by enrichment in genes associated with hallmarks of inflammation, epithelial mesenchymal transition (EMT), cell invasion and drug resistance. To determine the impact of hypoxic and acidic TME on cytotoxic response to anti-cancer drugs, the 2D and 3D adapted spheroids with or without additional exposure to low pH were screened against a library consisting of 184 anti-cancer drugs. Additional exposure to low pH led to an overall increase in drug resistance. However the combined hypoxic and acidic conditions in 3D revealed novel susceptibilities for compounds that belong to the family of Aurora kinase inhibitors. These results provide indications that accurate modeling of hypoxic and acidic TME in vitro could reveal expected resistance mechanisms and specific drug susceptibilities. This study introduces a 3D screening platform that recapitulates the acidosis and hypoxia of solid TME and captures the transcriptomic profile in vitro that is highly concordant with tumors in patients. This model allows the study of resistance mechanisms and unravel novel susceptibilities that is otherwise undiscovered in standard 2D conditions and could result in the identification of anticancer drugs that are more clinically relevant. Citation Format: Nazanin Rohani Larijani, Marielle Huot, Anne Lenferink, Noël R. Raynal. Mimicking tumor acidic and hypoxic microenvironment in vitro towards generation of more predictive screening platform for solid tumors [abstract]. In: Proceedings of the AACR Special Conference on the Evolutionary Dynamics in Carcinogenesis and Response to Therapy; 2022 Mar 14-17. Philadelphia (PA): AACR; Cancer Res 2022;82(10 Suppl):Abstract nr B041.

Well-orchestrated physico-chemical and biological factors for enhanced secretion of osteogenic and angiogenic extracellular vesicles by mesenchymal stem cells in a 3D culture format.

The secretome of mesenchymal stem cells (MSCs) is being studied for its regenerative potential for the treatment of various disorders, including bone diseases. However, mimicking the physiological parameters of native bone could further improve MSCs' secretory profile. The proteomic analysis revealed that MSCs have a diverse secretory profile depending on the cell formats used to grow them, such as two-dimensional (2D) or three-dimensional (3D) microenvironments. Stem cells are given biochemical and biophysical stimuli in a 3D milieu that mimics in vivo situations. Compared to the gold standard monolayer culture, extracellular vesicles (EVs) released under 3D conditions improved the EV cargo numerically and qualitatively. The higher requirements of EVs in clinical trials with consistent therapeutic potential are challenging. This review discusses the impact of cell culture formats on the regenerative potential of MSCs, specifically in bone regeneration. The poor yield and heterogeneity issues have hampered the therapeutic usage of EVs. Therefore, this review further explores various engineering approaches that could enhance EVs' scalability from MSCs and their therapeutic effectiveness beyond their native utility in bone tissue regeneration. This review also highlights some of the upcoming 3D approaches/models that might be useful for the enhanced secretion of therapeutic EVs from stem cells. Finally, we discuss possible future directions and conclusions in this domain.

The Influence of Antitumor Unsymmetrical Bisacridines on 3D Cancer Spheroids Growth and Viability.

The culture of 3D spheroids is a promising tool in drug development and testing. Recently, we synthesized a new group of compounds, unsymmetrical bisacridines (UAs), which exhibit high cytotoxicity against various human cell lines and antitumor potency against several xenografts. Here, we describe the ability of four UAs—C-2028, C-2041, C-2045, and C-2053—to influence the growth of HCT116 and H460 spheres and the viability of HCT116 cells in 3D culture compared with that in 2D standard monolayer culture. Spheroids were generated using ultra-low-attachment plates. The morphology and diameters of the obtained spheroids and those treated with UAs were observed and measured under the microscope. The viability of cells exposed to UAs at different concentrations and for different incubation times in 2D and 3D cultures was assessed using 7-AAD staining. All UAs managed to significantly inhibit the growth of HCT116 and H460 spheroids. C-2045 and C-2053 caused the death of the largest population of HCT116 spheroid cells. Although C-2041 seemed to be the most effective in the 2D monolayer experiments, in 3D conditions, it turned out to be the weakest compound. The 3D spheroid culture seems to be a suitable method to examine the efficiency of new antitumor compounds, such as unsymmetrical bisacridines.

OTME-15. Physical Confinement Induces Diverse Transcriptomic Changes and Chemoresistance in Migrating Glioblastoma Cells

Glioblastoma multiforme (GBM) cells migrating in physically confined environments are affected by mechanical stress that potentially lead to transcriptomic changes. To simulate those stresses, microfluidic channels were made with micro-patterned polydimethylsiloxane (PDMS) replicating the physical microenvironment of white matter tracts by confining the cells in linear channels similar to the space between axons. We employed a combination of microarray transcriptomic profiling and single cell-sequencing analyses to investigate cells undergoing linear confined space migration (LCSM). GBM cells spontaneously migrate through confined spaces along 5x5 mm (height/width) microfluidic channels, 0.5 to 5 mm in length. Our previous studies demonstrated that cells migrating in LCSM are more resistant to treatment with temozolomide than the same cells growing in standard monolayer culture (SMC). Cells in confined migration evaluated by microarray-based transcriptomic profiling demonstrated that linear confined migration induces increased expression in pathways involving angiogenesis, cell adhesion, cell motility, DNA damage repair, extracellular matrix structure, HIF1α, and others. Single cell transcriptomic analysis could identify GBM cells in different migratory states (LCSM vs. SMC), and similar pathways were seen upregulated with additional changes in cholesterol biosynthesis pathways and cell cycle regulation pathways. Trajectory Inference aligned single cells according to changes in migration status and demonstrated transcript changes during LCSM were progressive but generally reversible on return to SMC. Pathway analyses showed alterations in the cholesterol biosynthesis pathway and cell cycle regulation in cell clusters of confined migrating cells. Molecular studies confirmed that cholesterol biosynthesis pathway regulatory genes (SQLE, MVD, and HMGCR) are upregulated during LCSM. Expression analysis demonstrated increased G1 phase delay in confined migrating cells (LCSM) confirmed by FUCCI expression analysis. We propose that migration in linear confined spaces like white matter structures produces significant transcriptome changes that produce chemoresistance as a new mechanism for treatment resistance of Glioblastoma.

Paracrine Signaling from a Three-Dimensional Model of Bladder Carcinoma and from Normal Bladder Switch the Phenotype of Stromal Fibroblasts.

Simple SummaryThe aim of this work was to create a bladder carcinoma model to study the signals secreted by carcinoma cells in a in vivo-like context and how this molecular signaling can alter stromal fibroblasts. Our model is based on decellularized organ fragments (scaffolds) that aim to preserve the complexity of the native extracellular matrix of the bladder. Primary epithelial cells isolated from human bladder carcinoma were seeded on the scaffolds. We found that those cells showed a similar gene expression pattern when seeded on the scaffolds or on monolayer cultures. However, the secreted pattern of key growth factors was significantly different. Only the combination of factors secreted by carcinoma cells seeded on the scaffolds, but not the carcinoma cells seeded on plastic, was able to induce a pro-inflammatory or myofibroblast phenotype. This model allows one to decipher the paracrine pathways of bladder carcinoma in a defined in vitro system.We present a three-dimensional model based on acellular scaffolds to recreate bladder carcinoma in vitro that closely describes the in vivo behavior of carcinoma cells. The integrity of the basement membrane and protein composition of the bladder scaffolds were examined by Laminin immunostaining and LC–MS/MS. Human primary bladder carcinoma cells were then grown on standard monolayer cultures and also seeded on the bladder scaffolds. Apparently, carcinoma cells adhered to the scaffold basement membrane and created a contiguous one-layer epithelium (engineered micro-carcinomas (EMCs)). Surprisingly, the gene expression pattern displayed by EMCs was similar to the profile expressed by the carcinoma cells cultured on plastic. However, the pattern of secreted growth factors was significantly different, as VEGF, FGF, and PIGF were secreted at higher levels by EMCs. We found that only the combination of factors secreted by EMCs, but not the carcinoma cells grown on plastic dishes, was able to induce either the pro-inflammatory phenotype or the myofibroblast phenotype depending on the concentration of the secreted factors. We found that the pro-inflammatory phenotype could be reversed. We propose a unique platform that allows one to decipher the paracrine signaling of bladder carcinoma and how this molecular signaling can switch the phenotypes of fibroblasts.

Generation of Patient-Derived Colorectal Cancer Organoids for RAS Studies.

Human cell line models have been widely used for testing of novel anticancer compounds and for predicting clinical response to monotherapies and combinatorial therapies. For many years, standard monolayer culture conditions were used as gold standard, only surpassed by in vivo testing of mouse models. Recently, the incorporation of three-dimensional culture has been shown to further improve predictive compound testing. In view of the renewed interest in anti-RAS cancer therapy, we provide a protocol for establishing colorectal cancer organoids which are characterized by a high prevalence of KRAS mutations.

Differential Efficacy of Novel Antiviral Substances in 3D and Monolayer Cell Culture.

Repurposing of approved drugs that target host functions also important for virus replication promises to overcome the shortage of antiviral therapeutics. Mostly, virus biology including initial screening of antivirals is studied in conventional monolayer cells. The biology of these cells differs considerably from infected tissues. 3D culture models with characteristics of human tissues may reflect more realistically the in vivo events during infection. We screened first, second, and third generation epidermal growth factor receptor (EGFR)-inhibitors with different modes of action and the EGFR-blocking monoclonal antibody cetuximab in a 3D cell culture infection model with primary human keratinocytes and cowpox virus (CPXV) for antiviral activity. Antiviral activity of erlotinib and osimertinib was nearly unaffected by the cultivation method similar to the virus-directed antivirals tecovirimat and cidofovir. In contrast, the host-directed inhibitors afatinib and cetuximab were approx. 100-fold more efficient against CPXV in the 3D infection model, similar to previous results with gefitinib. In summary, inhibition of EGFR-signaling downregulates virus replication comparable to established virus-directed antivirals. However, in contrast to virus-directed inhibitors, in vitro efficacy of host-directed antivirals might be seriously affected by cell cultivation. Results obtained for afatinib and cetuximab suggest that screening of such drugs in standard monolayer culture might underestimate their potential as antivirals.

Characterization of primary mouse hepatocyte spheroids as a model system to support investigations of drug-induced liver injury

Primary mouse hepatocytes isolated from genetically defined and/or diverse lines and disease models are a valuable resource for studying the impact of genetic and environmental factors on drug response and disease. However, standard monolayer cultures result in a rapid decline in mouse hepatocyte viability and functionality. Therefore, we evaluated 3D spheroid methodology for long-term culture of primary mouse hepatocytes, initially to support investigations of drug-induced liver injury (DILI). Primary hepatocytes isolated from male and female C57BL/6J mice were used to generate spheroids by spontaneous self-aggregation in ultra-low attachment plates. Spheroids with well-defined perimeters were observed within 5 days after seeding and retained morphology, ATP, and albumin levels for an additional 2 weeks in culture. Global microarray profiling and quantitative targeted proteomics assessing 10 important drug metabolizing enzymes and transporters demonstrated maintenance of mRNA and protein levels in spheroids over time. Activities for 5 major P450 enzymes were also stable and comparable to activities previously reported for human hepatocyte spheroids. Time- and concentration-dependent decreases in ATP and albumin were observed in response to the DILI-causing drugs acetaminophen, fialuridine, AMG-009, and tolvaptan. Collectively, our results demonstrate successful long-term culture of mouse hepatocytes as spheroids and their utility to support investigations of DILI.

Abstract 2998: Linear confined space migration induces treatment resistance and gene expression changes in glioblastoma multiforme

Abstract Background: Glioblastoma Multiforme (GBM), an aggressive brain cancer, is known for its treatment resistant recurrence and lethality. The diffuse migration and invasion of GBM cells commonly occurs along brain white matter tracts in linear confined spaces between axons and has significant clinical implications as these cells survive initial therapies forming the main source of recurrent tumors resistant to therapies. In this context, this project aims to analyze the treatment resistance mechanism associated with linear confined space migrating cells (LCSM) to devise a better treatment strategy for GBM. Methods: We used a combination of microfluidic technology (5 µM wide channels in PDMS block) emulating linear white matter tracts in brain and standard molecular analysis (confocal microscopy, high content imaging, western blot, and flow cytometry) to investigate LCSM cells compared to Standard Monolayer Culture cells (SMCs) for the mechanism of drug resistance. Both established and patient derived GBM cell lines were used in the study. Results: LCSM cells were more resistant to chemo-drugs (Temozolomide and Doxorubicin) than SMCs as observed in cell viability assays. Enhanced drug efflux was observed in LCSM cells compared to SMC cells indicating the activation of drug efflux pumps. Protein expression analysis indicated that ABC drug efflux transporters (ABCB1, ABCC1, ABCG2) were activated or enhanced at varying levels in different LCSM cells compared to SMCs. Pharmacological inhibition of the prominently expressed ABCG2 protein using KO143 resulted in enhanced cell death by chemo drugs, suggesting that chemo resistance in LCSM, at least in part, is conferred by ABCG2 or other efflux transporters. In addition, CD133 (a marker of treatment resistant stem cell population in GBM) and AQP4 (Aquaporin 4; pro-migratory marker in GBM) were also enhanced in LCSM compared to SMC suggesting their possible roles in treatment resistance. Conclusion: Preliminary studies reveal that the enhanced expression ABC transporters, prominently ABCG2, might be responsible for enhanced drug efflux and low therapeutic sensitivity in GBM- LCSM cells. The over expression of AQP4 and CD133, and differential expression of other genes suggest that more complex mechanisms might be involved, which are currently under investigation. Citation Format: Anish Babu, Patrick McKernan, Xue Cai, James Battiste. Linear confined space migration induces treatment resistance and gene expression changes in glioblastoma multiforme [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2998.

The potential role of extracellular matrix in the activity of trabectedin.

e23542 Background: Soft tissue sarcomas (sts) represent a rare group of solid neoplasm of mesenchymal origin with a 1% incidence of all adult cancers. Liposarcoma and leiomyosarcoma (L-sarcoma) are the most common histotypes. The current first-line treatment for advanced/metastatic L-sarcomas is represented by anthracycline based-regimens. Second-line therapy options include trabectedin, eribulin, ifosfamide, gemcitabine and dacarbazine. In particular, the activity of trabectedin, a tetrahydroisoquinoline molecule, as well as its mechanism of action is not completely elucidated. Methods: The study involved six patient affected L-sarcoma. Patient-derived primary cultures were established after patient surgical treatment. Primary cells were cultured in standard monolayer culture and 3D collagen-based scaffolds. In order to gain inside into the mechanism of action of the drugs, genomic-, chemobiogram, proteomic-, cytometer and in silico analysis were performed. Results: The results confirmed the preservation of tumor gene expression in 3D culture model compared to standard monolayer culture. In particular 3D culture system was able to resemble the patient gene expression of TGFb, SLUG, SNAIL, MMP9 compared to 2D. In silico analysis showed an upregulation of COL1A1 gene, the extracellular matrix component of the present 3D model, in sts compared to other tumors. Pharmacological analysis displayed an increased sensitivity to trabectedin in all the 3D L-sarcoma primary culture compared to 2D culture system, while this was not observed with the other drugs. As previous preclinical evidences suggested that trabectedin mechanism of action include the impairing of ECM proteolytic degradation mediated by tumor cells, we think that its high observed sensitivity depend on the presence of collagen in our 3D- model. Conclusions: These results were suggestive of the losing credibility of monolayer standard culture for pharmacology studies and highlight the promising role of 3D patient-derived culture model for the study of sts biology. Moreover these results shed the light on the potential role of ECM in the mechanism of action of trabectedin in L-sarcomas. The work points out the role of this tumor microenvironment component in predicting response to trabectedin and provide the rationale for better stratifying patients which will be candidate for this drug. Further researches are needed to confirm these evidences.

Imaging the Cell Morphological Response to 3D Topography and Curvature in Engineered Intestinal Tissues.

While conventional cell culture methodologies have relied on flat, two-dimensional cell monolayers, three-dimensional engineered tissues are becoming increasingly popular. Often, engineered tissues can mimic the complex architecture of native tissues, leading to advancements in reproducing physiological functional properties. In particular, engineered intestinal tissues often use hydrogels to mimic villi structures. These finger-like protrusions of a few hundred microns in height have a well-defined topography and curvature. Here, we examined the cell morphological response to these villus-like microstructures at single-cell resolution using a novel embedding method that allows for the histological processing of these delicate hydrogel structures. We demonstrated that by using photopolymerisable poly(ethylene) glycol as an embedding medium, the villus-like microstructures were successfully preserved after sectioning with vibratome or cryotome. Moreover, high-resolution imaging of these sections revealed that cell morphology, nuclei orientation, and the expression of epithelial polarization markers were spatially encoded along the vertical axis of the villus-like microstructures and that this cell morphological response was dramatically affected by the substrate curvature. These findings, which are in good agreement with the data reported for in vivo experiments on the native tissue, are likely to be the origin of more physiologically relevant barrier properties of engineered intestinal tissues when compared with standard monolayer cultures. By showcasing this example, we anticipate that the novel histological embedding procedure will have a positive impact on the study of epithelial cell behavior on three-dimensional substrates in both physiological and pathological situations.

Multiomics characterization of mesenchymal stromal cells cultured in monolayer and as aggregates.

Mesenchymal stromal cells (MSCs) have failed to consistently demonstrate their therapeutic efficacy in clinical trials, due in part to variability in culture conditions used for their production. Of various culture conditions used for MSC production, aggregate culture has been shown to improve secretory capacity (a putative mechanism of action in vivo) compared with standard monolayer culture. The purpose of this study was to perform multiomics characterization of MSCs cultured in monolayer and as aggregates to identify aspects of cell physiology that differ between these culture conditions to begin to understand cellular-level changes that might be related to secretory capacity. Targeted secretome characterization was performed on multiple batches of MSC-conditioned media, while nontargeted proteome and metabolome characterization was performed and integrated to identify cellular processes differentially regulated between culture conditions. Secretome characterization revealed a reduction in MSC batch variability when cultured as aggregates. Proteome and metabolome characterization showed upregulation of multiple protein and lipid metabolic pathways, downregulation of several cytoskeletal processes, and differential regulation of extracellular matrix synthesis. Integration of proteome and metabolome characterization revealed individual lipid metabolites and vesicle-trafficking proteins as key features for discriminating between culture conditions. Overall, this study identifies several aspects of MSC physiology that are altered by aggregate culture. Further exploration of these processes and pathways is needed to determine their potential role in regulating cell secretory capacity.

Abstract P6-06-14: Analysis of secreted proteome in an in vivo like human 3D model of breast cancer

Abstract Background: Breast cancer is the most common form of cancer amongst women and affects millions worldwide each year. The tumor micro environment plays a key role in cancer progression and disease outcome of which a highly important factor is the secreted proteome which includes cytokines, chemokines and other proteins. Cancer cells influence neighboring cells by both autocrine and paracrine secretion which affects cancer cell characteristics such as stem-like properties, proliferation and metastatic capacity. Due to the importance of cancer cell signaling and cell to cell communication, when studying the cancer cell secretome in a three-dimensional environment new signaling pathways and new possible drug targets can be investigated. Methods: To understand the complexity of breast cancer cell secretion, the human in vivo like system patient derived scaffolds (PDS) was used as a modeling system whereby patient specific extracellular matrix mediated cellular secretion in both ERα+ and ERα- cell lines were investigated. 54 human breast cancer tumors were decellularized and the PDS were repopulated with either MCF7 or MDA-MB-231 cells. Cell lines were grown on scaffolds for 21 days. At day 16 cell media was changed and at day 21 conditioned media was collected for secretome analysis. Multiplex Proximity Extension Assay (OLINK, Uppsala Sweden) was performed on conditioned media and 184 proteins were analyzed for each sample. Results: The secretome from cells grown in PDS culture differs distinctly from the secretome from cells cultured in standard monolayer cultures, both in numbers and amount of secreted proteins. Secreted proteins from cells grown in PDS cultures were also shown to increase the cancer stem cell population compared to secretome from cells cultivated in monolayer culture. By comparing secretomic profiles from MCF7 cells grown in 54 PDSs, three clusters were created with an unsupervised clustering method. When these three clusters were correlated to clinical information about the specific tumors in each cluster, patients in one of the clusters were found to have a significantly lower chance of relapse-free survival and a higher frequency of high-grade tumors. Further, cells grown in PDS from this cluster also showed a different genetic profile with increased expression of markers related to epithelial-mesenchymal transition. Conclusion: Breast cancer cells grown in a three-dimensional in vivo-like model have a distinct different secretomic profile compare to monolayer cultured cells and the secretion can be related to the original characteristics of the breast tumor. This highlights the importance of the tumor microenvironment induced secretion and the possibility to target secreted proteins as a therapeutic strategy. Citation Format: Emma Persson, Pernilla Gregersson, Paul Fitzpatrick, Anna Gustafsson, Anders Ståhlberg, Göran Landberg. Analysis of secreted proteome in an in vivo like human 3D model of breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-06-14.

ESGCT 27th Annual Congress In collaboration with SETGyc Barcelona, Spain October 22–25, 2019 Abstracts

Xenotransplantation of transgenic porcine pancreatic islets offers a promising alternative source to circumvent current limitations posed by the scarcity of allogeneic donors. We have investigated the feasibility to generate tissue engineered SLA silenced islet cell clusters (ICC) to decrease xenogeneic immune responses Pancreatic islets single cell suspensions were generated by enzymatic digestion of porcine ICCs. Single cells were silenced for SLA expression by lentiviral vectors encoding for Nanoluciferase as reporter gene and for short hairpin RNAs targeting beta2-microglobulin or class II transactivator, respectively. SLA transcripts were evaluated by real-time PCR and protein levels by flow cytometry and fluorescence microscopy analyses. The effect of SLA silencing was evaluated in human T and NK cell cytotoxicity assays. SLA-silenced pancreatic beta-cells were then reassembled into ICCs in stirred bioreactors. SLA class I silencing reached a level of up to 84% and class II by up to 50% on pancreatic islet cell. Silencing SLA expression did not affect cell viability and the insulin-producing beta-cell phenotype. Xenogeneic T-cell immune responses (p < 0.05) as well as antibody-mediated cellular-dependent immune responses (p < 0.01) were significantly decreased. Silencing SLA class I expression did not increase susceptibility to NK-cell cytotoxicity. In stirred bioreactors, tissue engineered islets showing the typical 3D-structure and morphology of ICC were assembled from SLA-silenced pancreatic cell suspensions. These data shows the feasibility to generate low immunogenic porcine ICC from transgenic pigs after single cell engineering and post-transduction islet reassembling that might serve as a robust alternative to allogeneic pancreatic islet cell transplantation.

Three-Dimensional Leukemia Co-Culture System for In Vitro High-Content Metabolomics Screening

Metabolomics is increasingly applied to investigate different individuals and time-dependent responses to environmental stimuli. Rapid data acquisition and improved detection limits of direct infusion mass spectrometry (DIMS) are paving the way for applications of metabolomics in preclinical screening, opening new opportunities in drug discovery and personalized medicine. Three-dimensional (3D) cell culture systems, which mimic the in vivo cell microenvironment, are well recognized as tissue and organ substitutes.Here, we investigated cell viability and induction of reactive oxygen species (ROS) in stromal cells cultured in various 3D systems as well as the standard monolayer culture to evaluate which system provides the most favorable growing conditions. The selected 3D system was then tested for use in 3D co-culture of leukemia and stromal cells for DIMS-based high-throughput/high-content metabolic drug screens.The NanobioMatrix–poly(ε-caprolactone) (NBM–PCL) scaffold resulted in the lowest ROS production, supported rapid cell proliferation, and was suitable for the 96- and 384-well plate formats. Doxorubicin treatment in leukemia co-cultured with stromal cells induced some unique metabolic responses that drastically differed from those observed in leukemia cells alone. The DIMS results also showed that the drug-induced metabolic modulations in both normal and cancer cells were weakened by co-culturing even at high treatment doses, thereby demonstrating the value of the 3D co-culture high-content metabolic drug screen. In conclusion, we optimized a high sample throughput method for 3D co-culture with a DIMS-based high-content metabolic drug screen and drug development.

Abstract 58: High throughput 3D tumor model drug screening technology

Abstract Two-dimensional (2D) cancer cell cultures, or monolayers, remain the standard for testing cancer drugs prior to animal studies due to their simplicity and compatibility with standard plates and commercially available robotic tools. However, monolayer cell assays often fail to predict the efficacy of cancer drug candidates resulting in 80% of cancer drugs failing in animal drug studies and contributing to the extremely high costs of cancer drug discovery. Unlike solid tumors, the standard 2D cell cultures allow cancer cells unrestricted access to nutrients and oxygen and lack intercellular communications that result in inaccurate drug efficacy data. Three-dimensional (3D) tumor models are biologically relevant cell cultures that reproduce key properties such as diffusion limitations and cellular network of solid tumors that influence cancer drug efficacy. To promote the use of 3D cancer cell cultures in oncology drug discovery, OncoSolutions has engineered a novel technology to generate biologically relevant 3D tumor models that uniquely meets the needs of the pharmaceutical industry. OncoSolutions’ technology is highly robust and reliable for drug screening and available in high throughput format (1536 microplate) to accommodate the large drug libraries of the pharmaceutical industry. Importantly, the technology utilizes standard microplates that are compatible with commercially available automated liquid handling and analysis tools to reduce associated costs and increase speed for formation and analyses. OncoSolutions’ groundbreaking 3D culture technology is based on the immiscibility of highly aqueous solutions of polyethylene glycol (PEG) and dextran (DEX) to form a stable two-phase system. Cancer cells are mixed with the denser aqueous DEX phase solution and robotically dispensed as a nanodrop into a well of a standard microwell plate containing the immersion aqueous PEG phase. Cells remain entrapped in the nanodrop to autonomously form a single, compact 3D culture per well of the microplate within 24 hours. Unlike existing techniques, our technology quickly and reliably forms highly reproducible 3D cancer cell cultures with a standard deviation of less than 10% of the average 3D culture diameter within microplates. OncoSolutions’ technology has been used for biologically relevant standard chemotherapeutic testing and displayed superior robustness through Z-factor measurement (a statistical robustness measurement). In addition to evaluating the viability response of 3D cancer cell cultures generated with OncoSolutions’ technology, an assay for determining the apoptotic effects on 3D cancer cell cultures following drug treatment was optimized. Importantly, tumor models grown with OncoSolutions’ technology have provided more predictive models of animal drug responses than standard monolayer cultures and can reduce the time and costs associated with the high failure rate of cancer drugs in animal studies. Citation Format: Stephanie L. Ham, Emily Mulvany, Hossein Tavana. High throughput 3D tumor model drug screening technology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 58.

An in vivo Like Micro-Carcinoma Model.

We here present a novel micro-system which allows to reconstitute an in vivo lung carcinoma where the various constituting epithelial and/or stromal structural and/or cellular components can be incorporated at will. In contrast to various “organs on a chip” the model is based on the observation that in nature, epithelial cells are always supported by a connective tissue or stroma. The model is based on acellular micro-scaffolds of microscopic dimensions which enable seeded cells to obtain gases and nutrients through diffusion thus avoiding the need for vascularization. As a proof of concept, we show that in this model, Calu-3 cells can form a well-organized, continuous, polarized, one-layer epithelium lining the stromal derived alveolar cavities, and express a different pattern of tumor-related genes than when grown as standard monolayer cultures on plastic culture dishes. To our knowledge, this model, introduces for the first time a system where the function of carcinogenic cells can be tested in vitro in an environment that closely mimics the natural in vivo situation.