Abstract 3541: A method to visualize and quantify effects of immunotherapies in a physiologically relevant 3D TME model

INTRODUCTION: In vitro assays based on 3D co-cultures of cancer and immune cells present an opportunity to test diverse immunotherapies and understand their mechanisms of action in boosting anti-tumor immune responses in cancer patients. Incorporation of diverse cellular players, including cancer associated fibroblasts (CAFs) and suppressive myeloid cell populations, allows for faithful recapitulation of complex cellular interactions that occur in the tumor micro-environment (TME). The application of automation results in a high throughput platform which combines physiological relevance with assay robustness and reproducibility. Functional read-outs, such as migration of immune cells towards tumoroids, infiltration into the tumoroids and their killing are obtained by applying high content imaging, allowing for better understanding of the immune-modulatory profile of IO drugs. Here, we have applied image analysis to quantify the effects of different antibodies and small molecules targeting both the tumor and the T cells.

MATERIAL and METHODS: Tumoroids generated from breast and colon cancer organoids and cell lines were cultured in protein hydrogel. Partially HLA-matching T cells isolated from healthy PBMCs donors were added with or without activation to the 3D culture after incorporation of different suppressive populations, including CAFs and M2 macrophages. The capacity of effector T cells to infiltrate and subsequently kill tumor structures was visualized using high-content microscopy and quantified with morphometric image analysis software after reconstitution of 3D image stacks.

RESULTS and DISCUSSION: Automated 3D image and data analysis enabled discrimination of cellular interactions in a complex TME model. Depending on the activation status of T cells and the presence of suppressive cells in the environment, different levels of infiltration and tumor killing by effector T cells were measured. The suppression induced on the T cells by the environment was partially reversed by immune-modulators (e.g. CSF1R inhibitor) added to the co-culture, which was confirmed by increased IFNγ levels in culture supernatants. Two quantitative read outs that are strictly dependent on the 3D environment; T cell infiltration into tumor and decrease in tumor volume were combined to demonstrate immune suppression release induced by different immuno-modulators.

CONCLUSION: Our image-based platform described here allows for analysis of immunotherapy effects on cells that engage in a physiologically relevant spatial setting and in the presence of suppressive TME elements. Visualization and quantification of these complex cellular interactions within the TME empowers immunotherapy drug developers with a highly powerful tool to select the most promising candidates and better understand their mechanism of action, which ultimately will have an impact in the clinic.

Citation Format: Lidia Daszkiewicz, Gera Goverse, Nataliia Beztsinna, Saskia de Man, Tomas Veenendaal, Michelle Klop, Daniel Okkes, Ashgard Weterings, Kuan Yan, Leo Price. A method to visualize and quantify effects of immunotherapies in a physiologically relevant 3D TME model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3541.

Abstract 2059: Immunotherapy testing in 3D Ex vivo Patient Tissue Platform with preserved tumor microenvironment

Introduction Broad application of immunotherapy to treat cancer has been hampered by low response rates in the clinics (~20%) and high failure rates of clinical trials. The lack of translational preclinical models that accurately replicate human immunological complexity is one of the reasons leading to ineffective candidates in clinical trials. There is an urgent need of advanced preclinical models that can enhance clinical trial success rate and improve clinical impact of immunotherapies. We present a novel 3D Ex vivo Patient Tissue platform combining short-term 3D ex vivo tumor culture system with high content image (HCI)-based analysis. The platform preserves tumor heterogeneity and tumor immune context, including (exhausted) tumor infiltrating lymphocytes. We report a quantification of ex vivo tumor responses to a panel of immunotherapies, including checkpoint inhibitors, tested on patient tissues from various cancers.

Methods Patient tumor tissues were obtained from hospitals and tissue providers and processed within 24 hours to preserve the tumor microenvironment (TME). Tumor clusters from ovarian, cervical, breast, and non-small cell lung cancer patients were embedded in a protein-rich hydrogel and exposed to panels of immunomodulatory drugs in a 384-well format for 5-7 days. Phenotypic effects of the drugs on physiologically relevant morphological changes, such as tumor cell killing and immune cell proliferation, were measured using our proprietary automated HCI analysis platform. In addition, IHC and FACS analysis of primary samples as well as cytokine measurements were performed.

Results Responses of ex vivo tissues to immunotherapies targeting various pathways (e.g., ipilimumab, pembrolizumab and STING agonists), combination treatments and selected controls were evaluated by automated phenotypic analysis platform. Based on their sensitivity, patient tissues were classified as immunotherapy responders or non-responders. A deeper investigation of the responder tissues was performed with IHC and FACS to pinpoint the critical TME components necessary for immunotherapy sensitivity. In addition, cytokine profiling was done in supernatants from treated ex vivo cultures to confirm the functional HCI readouts. Accurate and reproducible response evaluation demonstrated the feasibility of preclinical immunotherapy drug testing on primary patient material using this platform.

Conclusion The 3D ex vivo patient tissue platform successfully combined drug testing protocols using fresh patient tumor tissue with preserved TME and advanced 3D HCI analysis. The platform offers a rapid, reliable and patient-relevant approach to test (clinical) immunotherapies for different solid tumours. It has the potential to significantly improve the preclinical evaluation of immunotherapies and support the decision-making process during progression of drug candidates to the clinic.

Citation Format: Nataliia Beztsinna, Niels Meesters, Lidia Daszkiewicz, Fanny Grillet, Donny van der Meer, Kuan Yan, Emma Spanjaard, Willemijn Vader, Leo Price. Immunotherapy testing in 3D Ex vivo Patient Tissue Platform with preserved tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2059.

Abstract P115: Novel patient avatar platform for oncology drug testing using 3D ex vivo models derived from fresh patient tumor tissues

Introduction The staggeringly high failure rate of clinical trials for oncology drugs can be attributed to many factors, including suboptimal in vitro and in vivo models that fail to recapitulate the complexity of the human tumor microenvironment (TME) or predict patient response. Translational human 3D cell culture models, such as patient-derived tumor organoids, have begun to bridge the gap between tissue culture systems and patients in the clinic. However, even in these advanced models, the endogenous cells of the TME, such as tumor infiltrating lymphocytes (TILs), fibroblasts, macrophages and other immune cells, are absent. These TME components have been shown to express important drug targets and play a critical role in both tumor progression and modulation of the response to drugs. Here we present a novel patient avatar platform that combines a short-term 3D ex vivo tumor culture system with high content image (HCI)-based analysis. Patient tumor tissues from pleural fluid, ascites, surgical resections or biopsy were tested ex vivo to preserve tumor heterogeneity and resident immune cells, removing the need for artificial co-culture systems. This study entailed a detailed quantification of tumor sensitivity to targeted therapies, standard of care, and novel (immune) drugs and drug combinations, tested on different cancer types. Methods Patient tumor tissues were obtained from ongoing clinical trials in the Netherlands as well as from commercial tissue providers, and processed within 24 hours to preserve the native tumor heterogeneity and TME. Freshly isolated tumor cells from ovarian, breast cancer and non small cell lung cancer (NSCLC) patients were embedded in a protein-rich hydrogel and exposed to panels of single and combination drug treatments at different concentrations in a 384-well format for 5-7 days. Effects of drugs and combination therapies on physiologically relevant morphological features, such as tumor cell killing, growth arrest, invasion and immune cell proliferation, were measured using our proprietary automated HCI analysis platform. Results Patient-specific drug sensitivity profiles were generated based on the response to a broad range of drugs including standard of care (e.g., platinum, paclitaxel, gemcitabine), targeted therapies (e.g., PARP and EGFR inhibitors), and activity of immunomodulatory drugs (e.g., ipilimumab, pembrolizumab and STING agonists). Accurate and reproducible response evaluation demonstrates the feasibility of preclinical drug testing on patient primary material within the platform. Conclusion Our platform successfully combined proven ex vivo drug testing protocols using fresh patient tumor tissue with preserved TME components and advanced 3D HCI analysis. Our approach offers a rapid, reliable and patient-relevant approach to test various candidate compounds (e.g., antibodies, antibody-drug conjugates and small molecules) for various cancer types. It has the potential to significantly improve the preclinical evaluation of drugs, and also to improve the success rate of clinical trials.

Citation Format: Nataliia Beztsinna, Fanny Grillet, Niels Meesters, Donny van der Meer, Lidia Daszkiewicz, Kuan Yan, Emma Spanjaard, Willemijn Vader, Leo Price. Novel patient avatar platform for oncology drug testing using 3D ex vivo models derived from fresh patient tumor tissues [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P115.

Abstract P113: Image-based quantification of immunotherapeutic effect on the tumor-immune interactions in 3D co-cultures

INTRODUCTION Despite the increasing number of immunotherapies available in preclinical cancer research and drug discovery pipelines, the number of patients benefiting from these immunotherapies remains extremely low. Moreover, the failure of immunotherapies in clinical trials remains very high to date. These high failure rates could be attributed to the lack of deep understanding the mechanism of action of drug candidates and to the absence of clinically relevant preclinical models that are suitable for drug screening purposes. To address these issues, we have developed an in vitro drug screening platform suitable for high-throughput testing in physiologically relevant 3D environment. Our preclinical drug testing platform is based on the co-culture of tumor cells with immune cells in 3D. Image analysis is applied to read out effects of drug candidates on immune cell migration, immune cell infiltration and tumoroid killing. MATERIALS AND METHODS 3D tumor cultures from human cancer cell lines (including breast, lung and colon cancer) or patient-derived colorectal organoids (from HUB Organoid Technology) were generated by embedding tumor cells in 3D ECM-like matrix constituted from protein hydrogel. Subsequently, different immune subsets, including PBMCs from healthy donors, T cells, NK cells or macrophages, were stained with cell tracker and added to the cultures. The cultures were treated with different immune-modulators (e.g. superantigens, activating antibodies, T cell engagers, CSFR1 inhibitor or STING agonist). The effect of immune-modulators on immune cell infiltration and their killing was assessed by high-content imaging and quantified after morphometric analysis with the proprietary Ominer® software. Immune cell-mediated killing was confirmed by measurement of IFNγ secretion in the culture supernatants. RESULTS Image-based analysis allowed for the dissection of complex tumor-immune cell interactions in the 3D cultures. Moreover, morphometric analysis revealed different levels of immune cell infiltration and tumoroid killing upon treatment with different immune-modulators. These effects could be reduced by inhibitory signals from the tumor microenvironment (TME) and were confirmed by the levels of IFNγ secreted by the immune cells. CONCLUSION Our in vitro platform allows quantitative image-based analysis of 3D tumor-immune cell co-cultures in a high-throughput manner, based on spatially resolved information in a more physiologically-relevant setting compared to traditional 2D cultures. This image-based analysis could be employed to dissect the effect of immunotherapy on different cell populations with the TME representing a promising tool to improve our understanding of the mechanism of action of novel treatments, treatment relapse and combination strategies, to eventually lead to a better clinical performance.

Citation Format: Lidia Daszkiewicz, Gera Goverse, Nataliia Beztsinna, Marjan van de Merbel, Benjamin Visser, Tomas Veenendaal, Emma Spanjaard, Kuan Yan, Leo Price. Image-based quantification of immunotherapeutic effect on the tumor-immune interactions in 3D co-cultures [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P113.

Abstract P158: Phenotypic analysis of myeloid cells in a 3D image-based repolarization assay with tumor spheroids

Background The immunosuppressive tumor microenvironment (TME) involves multiple cell types and a better understanding of the interplay between these cells could potentially unleash the full potential of many different types of immunotherapies. Tumor infiltrating myeloid cells have both cancer-restraining and cancer-promoting functions. Therefore, to further increase the biological relevance of in vitro platform, we incorporated the myeloid cell compartment into 3D co-cultures of tumor cells and T cells to measure the effects of immune-modulators. Using our proprietary image analysis software and machine learning, a set of morphological features was identified that allowed discrimination between undifferentiated monocytes, M1 and M2 macrophages, and dendritic cells. In addition, the phenotypic profiles of the myeloid cells could be analyzed in the presence of the tumor supernatants or in co-cultures with tumor cells. This assay allows a better understanding of the suppressive tumor microenvironment including multiple cell types and is suitable to test different cancer immunotherapies. Materials and Methods Different myeloid cell populations were generated from healthy PBMCs. Polarized M1 and M2 macrophages, DCs, and undifferentiated monocytes were then co-cultured with tumor conditioned media, spheroids derived from different cancer cell lines, or colorectal cancer organoids (CRC), growing in protein hydrogel in 384 well-plates for 1-7 days. In addition, purified T cells were also incorporated in these cultures. The cellular interactions were visualized using high-content microscopy and OMiner® software, which was trained to identify phenotypic profiles of different myeloid cell populations in 3D, was used to quantify their similarity to the defined subsets upon treatment. Results Myeloid cell populations were classified according to their phenotypic features identified by 3D image analysis, which verified the repolarization of M2 macrophages by their shift into phenotypic space of the M1 type macrophages upon treatment with CSF1r inhibitor or STING agonist. Repolarization was confirmed with an increased similarity score towards M1 macrophages upon treatment. This approach was further used to reveal the different effects of tumor cells and their immunosuppressive TME on myeloid cell phenotypes, showing that each tumor differently influenced the repolarization of the myeloid cells. In addition, triple co-cultures with T cells revealed the suppressive effect of tumor associated myeloid cells on the proliferation and infiltration of T cells. Conclusions The phenotypic analysis of different myeloid cells in 3D co-cultures could be visualized and quantified elucidating the bi-directional interplay between tumor and immune cells, and the functional reprograming of the suppressive tumor associated population towards an M1 phenotype induced by drug candidates. This advanced platform for testing cancer immunotherapies combines the ability to examine the complexity of the TME with the robustness of a high-throughput screening platform.

Citation Format: Gera Goverse, Nataliia Beztsinna, Benjamin Visser, Tomas Veenendaal, Marjan van de Merbel, Emma Spanjaard, Ashgard Weterings, Kuan Yan, Leo Price, Lidia Daszkiewicz. Phenotypic analysis of myeloid cells in a 3D image-based repolarization assay with tumor spheroids [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P158.

Abstract 4159: Ovarian cancer ex vivo 3D tumor cultures predict patient specific drug sensitivity

Introduction While systemic treatment has been quite static in the past decade in ovarian cancer, the challenge for the coming years is to stratify patients for optimal and new treatment strategies, such as targeting DNA damage response pathways, or immune modulation. Patient primary tumor from resections, biopsy or ascites can be cultured such that tumor heterogeneity and resident immune cells are preserved. These can be used to predict treatment response in patients or to test new cancer therapies. Here we present a high throughput short-term 3D ex-vivo culture platform combined with high content image-based analysis. This platform allows visualization and quantification of standard of care therapy and new drugs on fresh and cryopreserved patient derived ovarian cancer tumoroids.

Methods Patients with advanced primary or relapsing ovarian carcinoma are included in ongoing multi-center clinical trials in the Netherlands. Ovarian cancer derived tumoroids, freshly isolated or cryopreserved, are embedded in a protein-rich hydrogel and exposed to up to 20 drugs during a short term 3D culture. The automated high content imaging analysis platform measures a large panel of tumoroid morphological features, and responses such as tumor cell killing, growth arrest and local invasion are measured to define the response for each drug. In addition, clinical response data from the ongoing trials are collected to be correlated to clinical outcome of patients treated with systemic therapy.

Results We present results of drug sensitivity testing in patient-derived primary tumor cells of fresh and cryopreserved ascites and solid tumor. Patient-specific drug sensitivity is identified for up to 20 drugs including standard of care (e.g. carboplatin, paclitaxel) and novel treatment strategies (e.g. PARP inhibitors). Activity of immunomodulatory drugs were also monitored successfully in vitro. Accurate response evaluation demonstrates the feasibility of high-throughput drug screening on patient primary material within OcellO's platform. Our results show a high reproducibility in testing freshly isolated or cryopreserved material, highlighting the potential of a cryopreserved collection of patient derived primary material to test new drugs.

Conclusion OcellO's advanced 3D image analysis of patient primary material represents a rapid and biologically relevant approach to test various candidate compounds (e.g. antibodies, antibody-drug conjugates and small molecules) for ovarian cancer. The availability of drug response data combined with patient clinical data, including BRCA mutation and cytology/histology pathologist evaluation is expected to support drug discovery, improve the efficiency of clinical trials and establish predictive testing in the clinical setting.

Citation Format: Fanny Grillet, Abbas Jariani, Juul Overkamp, Lidia Daszkiewicz, Kuan Yan, Leo S. Price, Willemijn Vader. Ovarian cancer ex vivo 3D tumor cultures predict patient specific drug sensitivity [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 4159.

Abstract B137: Visualization and quantification of tumor-immune cell interactions in 3D cultures

Introduction: Despite the broad expansion of immunotherapies in cancer research field and drug discovery pipelines in the recent years, the actual number of patients who benefit from them is still extremely low and clinical trial failure rate is quite high. The main reason is that these treatments modalities enter the clinical space without proper understanding of mechanism of action and with a very weak rationale for combinations. However the progress in this direction is hampered by a lack of appropriate pre-clinical models, which remains one of the major bottlenecks in the immune-oncology research. Our goal is to address this issue by developing in vitro models that are both clinically relevant and suitable for routine screening of drug candidates. Experimental Procedures: To ensure the most accurate representation of the tumor biology, cancer cells are co-cultured with immune cells in a 3D setting. Tumor 3D cultures were generated from established cancer cell lines (e.g. breast, prostate) and colorectal cancer organoids (from HUB Organoid Technology) and seeded in 3D ECM-like matrix constituted from protein hydrogel. Different immune cells, such as PBMCs, purified T cells, dendritic cells or macrophages were added to the 3D tumor culture together with different immune-modulators and their effects on the infiltration of the immune cells into tumoroids and their killing was visualized using high-content imaging system. The quantification of these effects was achieved with morphometric analysis with proprietary OMinerTM software. Results: Multiparametric image-based analysis enabled the discrimination of complex immune-tumor cell interactions in 3D co-cultures. The effect of immune cell targeting on the tumor progression was clearly demonstrated by enhanced infiltration of T cells into the tumoroids and their increased killing in the presence of T cell engager. ADCC mechanism could be also depicted with this system. The reported here robust in vitro assay allows image based analysis of 3D cultures in a high-throughput manner. The 3D setting offers possibility to study active migration of immune cells towards tumoroids, infiltration of immune cells into the tumoroids and reduction of tumor volume; all of the functional read-ouds that are based on spatially resolved information. Conclusions: The developed image-based 3D platform allows for analysis of complex immunotherapy effects on different cell types that engage in a more physiologically relevant spatial setting compared to traditional 2D cultures. Preserving the third dimension also in the data analysis process provides a unique opportunity to measure spatially resolved information, not accessible by conventional monolayer cultures or biochemical assays. Visualization and quantification of tumor-immune cells interactions offer a highly powerful tool for cancer immunotherapy drug developers and brings a better understanding of the mechanism of action of novel treatments, which is ultimately translating to better clinical outcomes.

Citation Format: Lidia Daszkiewicz, Gera Goverse, Nataliia Beztsinna, Kuan Yan, Emma Spanjaard, Leo Price. Visualization and quantification of tumor-immune cell interactions in 3D cultures [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B137. doi:10.1158/1535-7163.TARG-19-B137

Abstract B139: Patient specific drug sensitivity to novel treatment approaches in ovarian cancer ex vivo 3D tumor cultures

Background: Many new drugs and treatment strategies are in development for ovarian cancer. While systemic treatment has been quite static in the past decade, the challenge for the coming years is to stratify ovarian cancer patients for optimal treatment strategies, like targeting DNA damage response pathways or immune modulatory approaches. Patient primary tumor material collection offers cryopreserved viable primary tumor cell clusters, containing the whole heterogeneity found in the patient ascites (including potential immune cells) to predict treatment response in patients or to test new cancer therapies. Here we present a high throughput short-term 3D ex-vivo culture platform combined with high content image-based analysis. This platform allows visualization and quantification of standard of care therapy and new drugs on fresh and cryopreserved patient derived ovarian cancer tumoroids. Methods: Patients with ovarian carcinoma are included in ongoing multi-center clinical trials in the Netherlands. Ovarian cancer derived primary tumoroids, freshly isolated or cryopreserved, are embedded in a protein-rich hydrogel and exposed to up to 20 drugs during a short term 3D culture. The automated high content imaging analysis platform measures a large panel of tumoroid morphological features, and responses such as tumor cell killing, growth arrest and local invasion are measured to define the response for each drug. In addition, clinical response data from the ongoing trials will be correlated to clinical outcome of patients treated with systemic therapy. Results:We present first results of drug sensitivity in patient-derived primary tumor cells of fresh and cryopreserved ascites. Patient-specific drug sensitivity is identified for up to 20 drugs including standard of care (e.g. carboplatin, paclitaxel) and novel treatment strategies (e.g. PARP inhibitors). Accurate response evaluation demonstrates the feasibility of high-throughput drug screening on patient primary material within OcellO’s platform. Our results show a high reproducibility in testing freshly isolated or cryopreserved material, highlighting the potential of a cryopreserved collection of patient derived primary material to test new drugs. Conclusion: OcellO’s advanced 3D image analysis of patient primary material represents a rapid and biologically relevant approach to test various candidate compounds (e.g. antibodies, antibody-drug conjugates and small molecules) for ovarian cancer. The availability of drug response data combined with patient clinical data, including BRCA mutation and cytology/histology pathologist evaluation is expected to support drug discovery, improve the efficiency of clinical trials and establish predictive testing in the clinical setting.

Citation Format: Fanny Grillet, Abbas Jariani, Juul Overkamp, Lidia Daszkiewicz, Kuan Yan, Leo Price, Willemijn Vader. Patient specific drug sensitivity to novel treatment approaches in ovarian cancer ex vivo 3D tumor cultures [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B139. doi:10.1158/1535-7163.TARG-19-B139

Abstract A065: Differential sensitivity of normal and tumor organoids to targeted therapies

Background: Advances in the culture of cells from human tissues have enabled the generation of normal and tumor organoid pairs derived from the same patient. These organoid cultures increase the scope for predicting responses to novel cancer therapeutics in patients. Here we present a high throughput 3D human intestinal organoid culture platform combined with high content image-based analysis. This platform allows visualization and quantification of responses beyond conventional cell viability measurements, including those associated with tumor killing, cell cycle arrest, toxicity and epithelial permeability and discriminates therapeutic and adverse responses in healthy tissue and tumor. Methods: Intestinal organoids, obtained from HUB Organoid Technology, cultured in natural extracellular matrix scaffolds show gene expression patterns, differentiation and functional characteristics that closely resemble the in vivo biology. To investigate the effect of standard-of-care (SoC) treatments, novel targeting antibodies and small molecules on tumor growth suppression and killing as well as function, formation and integrity of the gut epithelium, we tested a panel of normal and colorectal cancer organoids with a broad heterogeneity of mutations. 3D imaging and analysis was performed and responses in normal vs. tumor were compared. Results: High content 3D image analysis of the organoid enabled sensitive detection of treatment-induced and compound-specific morphological changes such as (inhibition of) growth, development, lumen formation, epithelial integrity and cell death. This enabled distinction between mechanisms of action and distinct effects and sensitivities in normal epithelium and tumor tissue from the same patient. Conclusion: 3D image analysis of in vitro cultured organoids represents a rapid and biologically relevant approach to test various anti-cancer-therapeutic modalities, including antibodies, antibody-drug conjugates and small molecules. Evaluating effects on healthy and tumor tissue from the same patient can give insight into potential toxicities and therapeutic window.

Citation Format: Mariusz Madej, Cinthya Del Angel Zuvirie, Jara García Mateos, Leo Price, Lidia Daszkiewicz, Kuan Yan, Bram Herpers. Differential sensitivity of normal and tumor organoids to targeted therapies [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A065. doi:10.1158/1535-7163.TARG-19-A065

Abstract 2083: Human normal and tumor colon organoids: a 3D high content screening platform for anticancer drug development

Background: Recent advances in establishing organoids from human specimens have enabled further development of advanced 3D cell culture models such as normal and tumor colon organoids derived from the same patient. These organoid cultures increase the scope for predicting treatment responses in patients, enabling the testing of cancer (immune)therapies, discriminating different drug responses and flagging off-target effects. Here we present a high throughput 3D human intestinal organoid culture platform combined with high content image-based analysis. This platform allows visualization and quantification of various treatment effects on healthy and diseased gut epithelium.

Methods: Intestinal organoids, obtained from HUB Organoid Technology, are cultured in natural extracellular matrix scaffolds and show gene expression patterns, differentiation and functional characteristics that closely resemble the in vivo biology. To investigate the effect of standard-of-care (SoC) treatments like 5-FU, Oxaliplatin and Irinotecan and/or (in combination with) novel targeting antibodies or other small molecules on the function, formation and integrity of the gut epithelium, we set up the following intestinal organoid test systems: 1. Colorectal cancer organoids with a broad heterogeneity of mutations for sensitive and high throughput phenotypic screening that enable accurate compound profiling and 2. Human normal vs. tumor organoid pair assays for off-target effect studies.

Results: High content 3D image analysis of the organoid models enables sensitive detection of treatment-induced and compound-specific morphological changes such as (inhibition of) growth, development, lumen formation, epithelial integrity and cell death. This enables distinction between mechanisms of action and determining compound synergy. The image-based measurements can be complemented with detection of secreted factors (e.g. cytokines, chemokines) or expressed genes in response to various therapeutic compounds.

Conclusion: OcellO’s advanced 3D image analysis of in vitro cultured organoids represents a rapid and biologically relevant approach to test various candidate compounds (e.g. antibodies, antibody-drug conjugates and small molecules) that can treat intestinal disorders such as Inflammatory Bowel Disease and colon cancer. This organoid technology also allows identifying potential adverse effects that can occur during in-vivo studies. Therefore, our intestinal organoid screening platform represents a significant advance on conventional in vitro models and helps bridge the translational gap between in vivo studies.

Note: This abstract was not presented at the meeting.

Citation Format: Mariusz Madej, Jara Garcia Mateos, Kuan Yan, Lidia Daszkiewicz, Bram Herpers, Leo S. Price. Human normal and tumor colon organoids: a 3D high content screening platform for anticancer drug development [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 2083.

Abstract LB-196: Image-based analysis of the interplay between myeloid cells and tumor cells in a 3D co-culture assay

BACKGROUND The myeloid cell compartment plays an important role in anti-tumor immune responses and represents a heterogeneous population with both cancer-promoting and cancer-restraining actions. Unleashing the full potential of cancer immunotherapies requires an understanding of the cellular mechanisms that govern these opposite actions. To date, high throughput relevant preclinical models for dissecting the interactions between different cellular players in the tumor microenvironment are lacking. Previously we have shown that a 3D image-based co-culture system allows assessing the efficacy of immune modulators that aim to enhance PBMC infiltration and tumoroid killing. Here, further improvements to the model are depicted. More specifically, we incorporated different myeloid cell populations to have a better representation of the human immune system in the tumor microenvironment (TME). In house developed software was trained on a set of features that enabled discrimination between undifferentiated monocytes, M1 and M2 macrophages and dendritic cells in 3D. Subsequently, these different myeloid subsets were co-cultured with tumoroids to analyze the complex cellular interactions that occur in the TME. This assay therefore offers the possibility to test cancer immunotherapies that target multiple cell types involved in anti-tumor immune responses and general modulation of suppressive tumor environment.

MATERIAL and METHODS Different myeloid populations were generated in 3D from monocytes derived from healthy donor PBMCs. Polarized M1 and M2 macrophages, DCs and undifferentiated monocytes were then co-cultured with spheroids derived from the SUM-149 breast cancer cell line, growing in protein hydrogel. The cellular interactions were visualized using high-content microscopy and quantified with multiparametric morphometric analysis with OMinerTM software.

RESULTS Using 3D image analysis different myeloid cells were distinguished from each other based on phenotypic measurements. In addition, our analysis enabled the discrimination of immune-tumor cell interactions and revealed the different effects of myeloid cells on tumor growth in co-culture. On the other hand, this approach also analyzes the tumor-driven mechanisms that can regulate myeloid cell differentiation and contribute to the immunosuppressive microenvironment, and can be used to study drug candidates targeting myeloid cells to promote tumor killing.

CONCLUSIONS The 3D assay presented here enables visualization and quantification of effects of immunotherapies on myeloid cells using morphological measurements. This co-culture system provides means to elucidate the bi-directional interplay between tumor and immune cells, allowing for analysis of functional reprograming of the suppressive population towards a M1 phenotype induced by drug candidates. This advanced platform for testing cancer immunotherapies also combines the complexity of the TME with the robustness of a high throughput screening platform.

Citation Format: Gera Goverse, Nataliia Beztsinna, Kuan Yan, Lars Guelen, Paul Vink, Leo Price, Lidia Daszkiewicz. Image-based analysis of the interplay between myeloid cells and tumor cells in a 3D co-culture assay [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 LB-196.

Abstract 1178: Image-based quantification of tumor-immune cell interactions in 3D cultures

INTRODUCTION Increasing numbers of cancer patients that benefit from immunotherapies and maintain durable response requires understanding of cellular mechanisms that govern anti-tumor immune responses. However, the mechanisms of action of these treatment modalities are not fully understood and the progress in this direction is hampered by a lack of appropriate pre-clinical testing models that are both clinically relevant and suitable for routine screening of drug candidates. Therefore, we developed a robust in vitro assay that allows image based analysis of 3D cultures in a high-throughput set-up. Here, immune cells are co-cultured with cancer cells in a 3D environment which recapitulates the tumor micro-environment and its complex cellular interactions. Functional read-outs, such as active migration of immune cells towards tumoroids, infiltration of immune cells into the tumoroids and their killing lead to a better understanding of the immune-modulatory profile of different immunotherapies.

MATERIAL and METHOD Tumoroids generated from cancer cell lines (e.g. breast, prostate) and colorectal cancer organoids (from HUB Organoid Technology) were cultured in protein hydrogel. Different immune cells, such as PBMCs, T cells, dendritic cells or macrophages, with and without activation were added to the 3D culture and their infiltration into tumoroids and subsequent killing was visualized using high-content microscopy. Quantification of immune cell effects was achieved with morphometric analysis with OMinerTM software.

RESULTS and DISCUSSION Image-based analysis enabled the discrimination of immune-tumor cell interactions in 3D cultures. These results demonstrated the effect of immune cell targeting on the tumor progression. Different levels of immune cells infiltration and killing of tumoroids and organoids were measured depending on the activation status of immune cells. The 3D environment, both for the cell culture and image analysis, allows for measurement of spatially resolved information, not accessible by monolayer cultures or biochemical assays.

CONCLUSION Our image-based platform described here allows for analysis of immunotherapy effects on different cell types that engage in a more physiologically relevant spatial setting than when culturing them in traditional 2D cultures. Visualization and quantification of these tumor-immune cells interactions offer a highly powerful tool for cancer immunotherapy drug developers to understand the mechanism of action of their treatments and ultimately translating to a better clinical performance.

Citation Format: Gera Goverse, Nataliia Beztsinna, Kuan Yan, Leo Price, Lidia Daszkiewicz. Image-based quantification of tumor-immune cell interactions in 3D cultures [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 1178.

Abstract 5562: A 3D image-based quantification of T cell-mediated killing of CRC organoids in the presence of immuno-modulators

BACKGROUND

Cancer immunotherapy has already yielded promising clinical results but most patients still do not respond. The mechanisms of action of these treatment modalities are also not fully understood and the progress in this direction is hampered by a lack of appropriate pre-clinical testing models. To investigate the role of novel therapeutics targeting the immune cell compartment to kill tumor cells, we developed an in vitro assay based on 3D cultures and image based analysis in a 384-wells plate format. Immune cells are added to recapitulate the tumor micro-environment and its complex interactions between different cellular players. Specifically, infiltration of immune cells into the tumoroids and their killing are visualized and measured, enabling a better understanding of the immune-modulatory profile of different treatments.

METHODS

Autologous patient derived colon organoids from normal and tumor tissue from several patients were cultured in a 3D environment. HLA-matched PBMCs with and without activation were added and immune-cell infiltration and killing of the CRC organoids was visualized in 3D using automated microscopy. Quantification of immune cell effects was achieved with morphometric analysis with OMinerTM software.

RESULTS

3D image data analysis enabled the discrimination of immune-tumor cell interactions and revealed a higher immune cell infiltration and tumoroid killing upon activation. In addition, we were able to compare both normal and tumor colon tissue from the same patient and compare between patients, demonstrating patient related differences and elucidating the effect of immune cell targeting on normal colon tissue.

CONCLUSIONS

The 3D assay presented here allows the analysis of different cell types that engage in a more realistic setting than when culturing them in traditional 2D cultures. Using image-based analysis, immune-tumor interactions can be visualized and quantified. The 3D environment, both for the cell culture and image analysis, allows for measurement of spatially resolved information, not accessible by monolayer cultures or biochemical assays. This new and innovative platform can empower immunotherapy drug developers to select the most promising candidates and better understand their mechanism of action.

Citation Format: Gera Goverse, Lidia Daszkiewicz, Kuan Yan, Mohamed Tleis, Mariusz Madej, Lucia Salinaro, Leo Price. A 3D image-based quantification of T cell-mediated killing of CRC organoids in the presence of immuno-modulators [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5562.

On How Fas Apoptosis-Independent Pathways Drive T Cell Hyperproliferation and Lymphadenopathy in lpr Mice

Fas induces massive apoptosis in T cells after repeated in vitro T cell receptor (TCR) stimulation and is critical for lymphocyte homeostasis in Fas-deficient (lpr) mice. Although the in vitro Fas apoptotic mechanism has been defined, there is a large conceptual gap between this in vitro phenomenon and the pathway that leads to in vivo development of lymphadenopathy and autoimmunity. A striking abnormality in lpr mice is the excessive proliferation of CD4⁺ and CD8⁺ T cells, and more so of the double-negative TCR⁺CD4⁻CD8⁻B220⁺ T cells. The basis of lpr T cell hyperproliferation remains elusive, as it cannot be explained by Fas-deficient apoptosis. T cell-directed p21 overexpression reduces hyperactivation/hyperproliferation of all lpr T cell subtypes and lymphadenopathy in lpr mice. p21 controls expansion of repeatedly stimulated T cells without affecting apoptosis. These results confirm a direct link between hyperactivation/hyperproliferation, autoreactivity, and lymphadenopathy in lpr mice and, with earlier studies, suggest that Fas apoptosis-independent pathways control lpr T cell hyperproliferation. lpr T cell hyperproliferation could be an indirect result of the defective apoptosis of repeatedly stimulated lpr T cells. Nonetheless, in this perspective, we argue for an alternative setting, in which lack of Fas would directly cause lpr T cell hyperactivation/hyperproliferation in vivo. We propose that Fas/Fas ligand (FasL) acts as an activation inhibitor of recurrently stimulated T cells, and that its disruption causes overexpansion of T cells in lpr mice. Research to define the underlying mechanism of this Fas/FasL effect could resolve the phenotype of lpr mice and lead to therapeutics for related human syndromes.

A 3D image-based quantification of immune cell-tumor spheroid interactions in the presence of checkpoint inhibition

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Background: Delivering on the promises of cancer immunotherapy is hampered by a lack of in vitro testing platforms that enable the early selection of promising drugs candidates. While quantification of the number of cytotoxic T cells and IFNγ secretion can give an indication of the drug effect, it is often critical to assess the functional cytotoxicity and infiltration capacity. In addition, immunomodulatory effects of drug combinations need to be carefully assessed before these treatment modalities reach patients. However there are unlimited possibilities of new combinations, especially in the view of synergy effects observed with double checkpoint inhibition blockade and combination with standard of care drugs. To specifically address the needs of immunotherapy cancer drug developers, we developed robust assays that incorporate the human immune system into tumor spheroid cultures, with functional read-outs in a high throughput (384well plate) format. Methods: Breast cancer cells were grown in a hydrogel to form 3D tumoroids. HLA-matched PBMCs with and without pre-activation/exhaustion were added and the infiltration of T cells and subsequent tumoroid killing was quantified. The effect of immune checkpoint blockade was also assessed with the addition of pembrolizumab. Quantification of effects of stimulators and checkpoint inhibition was achieved with 3D imaging and morphometric analysis with OMiner software. Results: Automated 3D image and data analysis enabled discrimination of immune-tumour cell interactions depending on activation status of T cells. Activated T cells more efficiently infiltrated and killed tumoroids than non-activated ones. Cytotoxic activity of overactivated/exhausted T cells was supressed but this could be reversed by the presence of checkpoint inhibitor in the coculture. Conclusions: A 3D environment allows the different cell types to engage in a more realistic setting than when cells are grow in a monolayer. Using image-based analysis, immune-tumor interactions can be dissected. This represents a new, highly powerful tool for cancer immunotherapy drug developers to select the most promising compounds, allowing faster progression towards the clinic.

Intralymphatic mRNA vaccine induces CD8 T-cell responses that inhibit the growth of mucosally located tumours

The lack of appropriate mouse models is likely one of the reasons of a limited translational success rate of therapeutic vaccines against cervical cancer, as rapidly growing ectopic tumours are commonly used for preclinical studies. In this work, we demonstrate that the tumour microenvironment of TC-1 tumours differs significantly depending on the anatomical location of tumour lesions (i.e. subcutaneously, in the lungs and in the genital tract). Our data demonstrate that E7-TriMix mRNA vaccine-induced CD8⁺ T lymphocytes migrate into the tumour nest and control tumour growth, although they do not express mucosa-associated markers such as CD103 or CD49a. We additionally show that despite the presence of the antigen-specific T cells in the tumour lesions, the therapeutic outcomes in the genital tract model remain limited. Here, we report that such a hostile tumour microenvironment can be reversed by cisplatin treatment, leading to a complete regression of clinically relevant tumours when combined with mRNA immunization. We thereby demonstrate the necessity of utilizing clinically relevant models for preclinical evaluation of anticancer therapies and the importance of a simultaneous combination of anticancer immune response induction with targeting of tumour environment.

Intratumoral administration of mRNA encoding a fusokine consisting of IFN-β and the ectodomain of the TGF-β receptor II potentiates antitumor immunity

It is generally accepted that the success of immunotherapy depends on the presence of tumor-specific CD8⁺ cytotoxic T cells and the modulation of the tumor environment. In this study, we validated mRNA encoding soluble factors as a tool to modulate the tumor microenvironment to potentiate infiltration of tumor-specific T cells. Intratumoral delivery of mRNA encoding a fusion protein consisting of interferon-β and the ectodomain of the transforming growth factor-β receptor II, referred to as Fβ², showed therapeutic potential. The treatment efficacy was dependent on CD8⁺ T cells and could be improved through blockade of PD-1/PD-L1 interactions. In vitro studies revealed that administration of Fβ² to tumor cells resulted in a reduced proliferation and increased expression of MHC I but also PD-L1. Importantly, Fβ² enhanced the antigen presenting capacity of dendritic cells, whilst reducing the suppressive activity of myeloid-derived suppressor cells. In conclusion, these data suggest that intratumoral delivery of mRNA encoding soluble proteins, such as Fβ², can modulate the tumor microenvironment, leading to effective antitumor T cell responses, which can be further potentiated through combination therapy.

Targeting the tumor microenvironment to enhance antitumor immune responses

The identification of tumor-specific antigens and the immune responses directed against them has instigated the development of therapies to enhance antitumor immune responses. Most of these cancer immunotherapies are administered systemically rather than directly to tumors. Nonetheless, numerous studies have demonstrated that intratumoral therapy is an attractive approach, both for immunization and immunomodulation purposes. Injection, recruitment and/or activation of antigen-presenting cells in the tumor nest have been extensively studied as strategies to cross-prime immune responses. Moreover, delivery of stimulatory cytokines, blockade of inhibitory cytokines and immune checkpoint blockade have been explored to restore immunological fitness at the tumor site. These tumor-targeted therapies have the potential to induce systemic immunity without the toxicity that is often associated with systemic treatments. We review the most promising intratumoral immunotherapies, how these affect systemic antitumor immunity such that disseminated tumor cells are eliminated, and which approaches have been proven successful in animal models and patients.

Distinct p21 requirements for regulating normal and self-reactive T cells through IFN-γ production

Self/non-self discrimination characterizes immunity and allows responses against pathogens but not self-antigens. Understanding the principles that govern this process is essential for designing autoimmunity treatments. p21 is thought to attenuate autoreactivity by limiting T cell expansion. Here, we provide direct evidence for a p21 role in controlling autoimmune T cell autoreactivity without affecting normal T cell responses. We studied C57BL/6, C57BL/6/lpr and MRL/lpr mice overexpressing p21 in T cells, and showed reduced autoreactivity and lymphadenopathy in C57BL/6/lpr, and reduced mortality in MRL/lpr mice. p21 inhibited effector/memory CD4(+) CD8(+) and CD4(-)CD8(-) lpr T cell accumulation without altering defective lpr apoptosis. This was mediated by a previously non-described p21 function in limiting T cell overactivation and overproduction of IFN-γ, a key lupus cytokine. p21 did not affect normal T cell responses, revealing differential p21 requirements for autoreactive and normal T cell activity regulation. The underlying concept of these findings suggests potential treatments for lupus and autoimmune lymphoproliferative syndrome, without compromising normal immunity.

p21 selectively regulates the activation of autoimmune of lpr memory T cells and attenuates autoimmunity (60.5)

Fas drives activated T cell apoptosis in vitro, but lymphadenopathy and lupus in Fas-deficient (lpr) mice cannot be explained only on the basis of the lpr T cell apoptotic defect. Unexplained also remains the hyperproliferation of T cells in lpr mice, including CD4+, CD8+ and CD4-CD8-TCR+ cells. We investigate these questions by generating T cell-specific p21-transgenic and p21-/- BL/6 lpr mice. p21, a cell cycle inhibitor and a lupus-like autoimmunity suppressor, regulates memory T cell but not naïve T cell expansion. p21 overexpression in lpr T cells did not affect primary T cell responses, but profoundly diminished lpr T cell expansion upon repeated activation, without affecting the apoptosis defect of lpr T cells. Importantly, p21 overexpression restrains lpr T cell memory expansion and IFN-gamma and IL-17 production, resulting in reduced autoantibody production, glomerulonephritis and lymphadenopathy in lpr mice. In p21-/- lpr mice, lack of p21 enhanced the activation and accumulation of memory T cells, which produced higher levels of IFN-gamma and IL-17. Lack of p21 led to severe glomerulonephritis and death in BL/6 lpr mice, which normally develop non-lethal mild autoimmunity. Overall, we conclude that independently of their lpr apoptotic defect, T cell hyperactivation and autoimmunity development can be controlled by p21. Thus, analysis of the role of p21 in T cell immunity may be of therapeutic value for both Lupus and the Autoimmune Lymphoproliferative Syndrome.

Fas and p21 suppress autoimmunity by regulating cell cycle progression of effector/memory T cells (167.19)

Fas drives activated T cell apoptosis in vitro, but lymphadenopathy and lupus development in Fas-deficient (lpr) mice cannot be explained only on the basis of the lpr T cell apoptotic defect. Unexplained also remains the in vivo hyperproliferation of T cells in lpr mice, including CD4+, CD8+ and CD4-CD8-TCR+ cells. To date, the effect of lpr T cell-hyperproliferation in both lymphadenopathy and lupus autoimmunity is not known. We investigate this point by generating T cell-specific p21-trangenic -lpr mice. p21, a cell cycle inhibitor and a lupus-like autoimmunity suppressor, regulates the expansion of memory but not of naïve T cells. p21 overexpression in lpr T cells did not affect primary T cell responses, but profoundly diminished lpr T cell proliferation after secondary activation, without affecting the compromised apoptotic cell death of lpr T cells. Importantly, in vivo, p21 overexpression restrains lpr T cell memory expansion, and results in reduced autoantibody production, glomerulonephritis and lymphadenopathy in lpr mice. p21 overexpression did not affect T cell memory in wt mice, pointing to a specialized role for p21 in hyperproliferating T cells. Overall we conclude that lpr T cell hyperproliferation is essential for the increased T cell memory, the autoimmunity and the lymphadenopathy development in lpr mice. Thus, decreasing the hyperproliferation of pathogenic T cells may be of therapeutic value for both Lupus and the Autoimmune Lymphoproliferative Syndrome.