Organoid Co-cultures Research Articles

Abstract IA001: Patient-derived tumor organoids to probe the cancer immune interface

Abstract The development of rational (combination) immunotherapies is limited by an incomplete understanding of what determines a tumor’s sensitivity to immune attack. Despite great heterogeneity in resistance mechanisms between patients, functional model systems to study cancer/immune cell interactions at the level of individual patients have been lacking. Here we highlight the potential of organoid/immune cell co-cultures as individualized models of anti-tumor immunity. First, we established a co-culture platform of autologous tumor organoids and peripheral blood lymphocytes from patients with mismatch-repair deficient colorectal cancer (dMMR-CRC) and non-small-cell lung cancer (NSCLC). This allows enriching tumor-reactive T cells from peripheral blood of individual patients, and creating personalized test systems to evaluate their capacity to kill matched tumor organoids. Second, subclonal immune escape is a major barrier to achieving complete responses to cancer immunotherapies. While most tumours consist of multiple genetically distinct clones, directly investigating the potential for immune escape at the clonal level has been impossible so far, due to challenges in isolating and propagating individual tumour subclones from human cancers for functional studies. By leveraging the multi-region TRACERx study, we established multi-region organoid libraries of >20 parallel sublines from patients with NSCLC. Co-cultures of each subline with autologous tumour infiltrating lymphocytes (TIL) reveal substantial heterogeneity in the capacity of individual clonal sublines to elicit a T-cell response. We show that subclonal immune escape can be mediated by antigen-dependent and -independent mechanisms. These results show (i) that tumour evolution can give rise to distinct cancer clones with intrinsic differences in immune evasion capacity and (ii) provide an approach to prospectively identify and isolate immune evading subclones from cancer patients. Third, analysis of a clinical cohort of patients treated with anti-PD1 therapy revealed that gamma delta T cells are critical mediators of the response in dMMR-CRC patients with genetic inactivation of beta-2-microglobulin (B2M). Co-cultures of organoids and gamma delta T cells provide direct evidence that loss of B2M increases reactivity of patient-derived gamma delta T cells towards tumor organoids. This highlights the need for functional models that move beyond conventional T cells. Future developments are directed towards establishment of complex co-culture systems to study how communication between organoids and immune cells is mediated by cell surface factors and secreted molecules, and how cellular crosstalk is altered in cancer. Citation Format: Krijn K Dijkstra. Patient-derived tumor organoids to probe the cancer immune interface [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr IA001.

CNSC-33. MOLECULAR AND FUNCTIONAL DRIVERS OF ACTIVITY DEPENDENT GLIOBLASTOMA PROLIFERATION

Abstract Glioblastoma, the most common primary brain tumor in adults, is a major cause of neurological morbidity and mortality with no effective therapies. Its proliferation and invasion are regulated by direct and paracrine-mediated neuronal activity. In this study, we uncover molecular targets and protein-protein signaling driving activity dependent proliferation. To identify candidate molecular pathways, we used high-density electrode arrays in vivo to record human local field potentials. Single-cell RNA sequencing identified Netrin-G1 (NTNG1) and thrombospondin-1 (TSP1) elevation in glioblastoma clonal population that proliferates in response to the presence of neurons. The amino acid sequence of NTNG1 and the TSR1 domain of TSP1 were utilized to predict the 3D interaction surface of NTNG1 and TSP1. Compared to structure predictions of NTNG1 and its known binding partner NGL1, NTNG1 and TSP1 complex predictions showed agreement between machine learning predicted models and lower predicted aligned error in interdomain regions of the complex, suggesting higher confidence in the relative position of NTNG1-TSP1 as compared to NTNG1-NGL1. We performed 45 protein structure predictions and two molecular dynamics simulations of mutant and WT TSP1 in complex with NTNG1. Each simulation box consisted of >263,000 atoms, each run for 50 million 2 femtosecond timesteps for a total simulation time of 200 ns. These calculations confirmed a stable complex in the WT condition and significant conformational change in the R46A condition, emphasizing the importance of this residue in mediating NTNG1-TSP1 binding. Computational affinity models between NTNG1 and TSP1 were validated by pull-down assays and immunofluorescence labelling using cerebral organoid and human glioma-neuronal coculture models. Finally, we design small molecule and fusion-protein inhibitors disrupting this interaction. Here we advance the development of targeted precision-medicine therapies to treat glioblastoma proliferation through activity-dependent mechanisms.

Genetic vulnerability to Crohn's disease reveals a spatially resolved epithelial restitution program.

Effective tissue repair requires coordinated intercellular communication to sense damage, remodel the tissue, and restore function. Here, we dissected the healing response in the intestinal mucosa by mapping intercellular communication at single-cell resolution and integrating with spatial transcriptomics. We demonstrated that a risk variant for Crohn's disease, hepatocyte growth factor activator (HGFAC) Arg509His (R509H), disrupted a damage-sensing pathway connecting the coagulation cascade to growth factors that drive the differentiation of wound-associated epithelial (WAE) cells and production of a localized retinoic acid (RA) gradient to promote fibroblast-mediated tissue remodeling. Specifically, we showed that HGFAC R509H was activated by thrombin protease activity but exhibited impaired proteolytic activation of the growth factor macrophage-stimulating protein (MSP). In Hgfac R509H mice, reduced MSP activation in response to wounding of the colon resulted in impaired WAE cell induction and delayed healing. Through integration of single-cell transcriptomics and spatial transcriptomics, we demonstrated that WAE cells generated RA in a spatially restricted region of the wound site and that mucosal fibroblasts responded to this signal by producing extracellular matrix and growth factors. We further dissected this WAE cell-fibroblast signaling circuit in vitro using a genetically tractable organoid coculture model. Collectively, these studies exploited a genetic perturbation associated with human disease to disrupt a fundamental biological process and then reconstructed a spatially resolved mechanistic model of tissue healing.

Bioengineering Approaches for the Pancreatic Tumor Organoids Research and Application.

Pancreatic cancer is a highly lethal form of digestive malignancy that poses significant health risks to individuals worldwide. Chemotherapy-based comprehensive treatment is the primary therapeutic approach for midlife and late-life patients. Nevertheless, the heterogeneity of the tumor and individual genetic backgrounds result in substantial variations in drug sensitivity among patients, rendering a single treatment regimen unsuitable for all patients. Conventional pancreatic cancer tumor organoid models are capable of emulating the biological traits of pancreatic cancer and are utilized in drug development and screening. However, these tumor organoids can still not mimic the tumor microenvironment (TME) in vivo, and the poor controllability in the preparation process hinders translation from essential drug screening to clinical pharmacological therapy. In recent years, many engineering methods with remarkable results have been used to develop pancreatic cancer organoid models, including bio-hydrogel, co-culture, microfluidic, and gene editing. Here, this work summarizes and analyzes the recent developments in engineering pancreatic tumor organoid models. In addition, the future direction of improving engineered pancreatic cancer organoids is discussed for their application prospects in clinical treatment.

P02.05.A DISSECTING THE DIFFUSE MIDLINE GLIOMA TUMOUR MICROENVIRONMENT COMMUNICATIONS USING MULTI-OMICS APPROACHES

Abstract BACKGROUND Diffuse midline glioma (DMG) represents a highly aggressive pediatric brain tumour with no chance of survival. Treatment options are urgently needed, and efforts have been put towards the development of T cell immunotherapy. However, this should consider the unique tumour microenvironment (TME) of DMG, both in terms of anatomical location and developmental stage. MATERIAL AND METHODS To gain knowledge on this unique tumour niche, we implemented an immuno-competent, syngeneic mouse model based on in-utero electroporation (IUE) of the key driver-mutations to induce tumour formation at embryonic stage. By combining snRNAseq, Spatial Transcriptomics and state-of-the-art imaging, we characterized the spatial and molecular landscape of DMG. RESULTS AND CONCLUSION We observed a high intratumoral heterogeneity with spatially restricted cell populations. Importantly, their molecular profiles correlate with patient data, illustrating the clinical relevance of the IUE model. Analysis of cell-cell communications in the TME revealed a novel signalling between DMG and immunosuppressive myeloid cells, that could impact T-cell response. Using an advanced patient-derived DMG organoid co-culture model with macrophages and engineered T-cells, we are currently investigating the role of this pathway on T-cells mediated killing of DMG organoids. Thus, this project fills a critical need to delineate and overcome the immune-suppressive environment in DMG and potentiate T cell targeting.

Network pharmacology and experimental verification reveal the mechanism of safranal against glioblastoma (GBM).

Safranal is an active component of the traditional Tibetan medicine (TTM) saffron, which has potential anticancer activity. Here, we studied the therapeutic effect and mechanism of safranal on GBM. CCK-8, GBM-brain organoid coculture experiments and 3D tumour spheroid invasion assays showed that safranal inhibited GBM cell proliferation and invasion in vitro. Network pharmacology, RNA-seq, molecular docking analysis, western blotting, apoptosis, and cell cycle assays predicted and verified that safranal could promote GBM cell apoptosis and G2/M phase arrest and inhibit the PI3K/AKT/mTOR axis. In vivo experiments showed that safranal could inhibit GBM cell growth alone and in combination with TMZ. This study revealed that safranal inhibits GBM cell growth in vivo and in vitro, promotes GBM cell apoptosis and G2/M phase arrest, inhibits the PI3K/AKT/mTOR axis and cooperate with TMZ.

Short-term PM2.5 exposure induces transient lung injury and repair

Exposure to fine atmospheric particulate matter (PM) is known to induce lung inflammation and injury; however, the way in which sophisticated endogenous lung repair and regenerative programs respond to this exposure remains unknown. In this study, we established a whole-body mouse exposure model to mimic real scenarios. Exposure to fine PM (PM with an aerodynamic diameter ≤ 2.5 µm [PM2.5]; mean 1.05 mg/m3) for 1-month elicited inflammatory infiltration and epithelial alterations in the lung, which were resolved 6 months after cessation of exposure. Immune cells that responded to PM2.5 exposure mainly included macrophages and neutrophils. During PM2.5 exposure, alveolar epithelial type 2 cells initiated rapid repair of alveolar epithelial mucosa through proliferation. However, the reparative capacity of airway progenitor cells (club cells) was impaired, which may have been related to the oxidative production of neutrophils or macrophages, as suggested in organoid co-cultures. These data suggested that the pulmonary toxic effects of short-term exposure to fine atmospheric PM at a certain dosage could be overcome through tissue reparative mechanisms.

Organoid co-culture model of the human endometrium in a fully synthetic extracellular matrix enables the study of epithelial-stromal crosstalk

The human endometrium undergoes recurring cycles of growth, differentiation, and breakdown in response to sex hormones. Dysregulation of epithelial-stromal communication during hormone-mediated signaling may be linked to myriad gynecological disorders for which treatments remain inadequate. Here, we describe a completely defined, synthetic extracellular matrix that enables co-culture of human endometrial epithelial and stromal cells in a manner that captures healthy and disease states across a simulated menstrual cycle. We parsed cycle-dependent endometrial integrin expression and matrix composition to define candidate cell-matrix interaction cues for inclusion in a polyethylene glycol (PEG)-based hydrogel crosslinked with matrix metalloproteinase-labile peptides. We semi-empirically screened a parameter space of biophysical and molecular features representative of the endometrium to define compositions suitable for hormone-driven expansion and differentiation of epithelial organoids, stromal cells, and co-cultures of the two cell types. Each cell type exhibited characteristic morphological and molecular responses to hormone changes when co-encapsulated in hydrogels tuned to a stiffness regime similar to the native tissue and functionalized with a collagen-derived adhesion peptide (GFOGER) and a fibronectin-derived peptide (PHSRN-K-RGD). Analysis of cell-cell crosstalk during interleukin 1B (IL1B)-induced inflammation revealed dysregulation of epithelial proliferation mediated by stromal cells. Altogether, we demonstrate the development of a fully synthetic matrix to sustain the dynamic changes of the endometrial microenvironment and support its applications to understand menstrual health and endometriotic diseases. This work was supported by The John and Karine Begg Foundation, the Manton Foundation, and NIH U01 (EB029132).

In-vitro model to mimic T cell subset change in human PDAC organoid co-culture

PurposeImmunotherapies have largely failed as treatment options for pancreatic ductal adenocarcinoma (PDAC). In this field, clinical translational studies into personalized treatment are of fundamental importance. In our study, we model tumor-cell immune-cell interactions in a co-culture of primary human PDAC organoids and matched peripheral blood mononuclear cells (PBMCs).MethodsUsing flow cytometry, we evaluated changes in T cell subtypes upon co-culture of patient-derived PDAC organoids and matched PBMCs.ResultsAfter co-culturing PDAC organoids with PBMCs, we observed changes in CD4+, CD8+ and Treg cell populations. We observed favorable clinical outcome in patients whose PBMCs reacted to the co-culture with organoids.ConclusionThis experimental model allows to investigate interactions between patient derived PDAC organoids and their PBMCs. This co-culture system could serve as a preclinical platform to guide personalized therapeutic strategies in the future.

Validation of a Novel EUS-FNB-Derived Organoid Co-Culture System for Drug Screening in Patients with Pancreatic Cancer.

Cancer-associated fibroblasts (CAFs) have been shown to impact the chemosensitivity of patient-derived tumor organoids (PDTOs). However, the published literature comparing PDTO response to clinical outcome does not include CAFs in the models. Here, a co-culture model was created using PDTOs and CAFs derived from endoscopic ultrasound-guided fine-needle biopsies (EUS-FNBs) for potential use in drug screening applications. Co-cultures were established, and growth was compared to monocultures using image metrics and a commercially available assay. We were able to establish and expand validated malignant PDTOs from 19.2% of adenocarcinomas from EUS-FNBs. CAFs could be established from 25% of the samples. The viability of PDTOs in the mixed cell co-culture could be isolated using image metrics. The addition of CAFs promoted PDTO growth in half of the established co-cultures. These results show that co-cultures can be established from tiny amounts of tissue provided by EUS-FNB. An increased growth of PDTOs was shown in co-cultures, suggesting that the present setup successfully models CAF-PDTO interaction. Furthermore, we demonstrated that standard validation techniques may be insufficient to detect contamination with normal cells in PDTO cultures established from primary tumor core biopsies.

EXPLORING THE INTERPLAY BETWEEN BRAIN TUMOUR INITIATING CELLS AND THE TUMOUR MICROENVIRONMENT: POTENTIAL TARGETING STRATEGIES FOR GLIOBLASTOMA

Abstract The aggressive biology and poor response to therapy resulting in relapse of patients with GBM is attributed to the existence of Brain Tumour Initiating Cells (BTICs) with stem cell properties. Targeting BTICs in isolation of their surrounding tumour microenvironment (TME) has proven ineffective. Determining the molecular effects of the TME on BTICs is an evolving area that requires more focus. OUR APPROACH: Using innovative patient-derived organoid co-culture models paired with an in vivo zebrafish xenograft system our multidisciplinary team is exploring the biology of BTICs in the context of their microenvironment in search for novel therapeutic options that will benefit GBM patients. RESULTS: Our data supports an important role for activated cancer associated fibroblasts and endothelial cells in driving BTIC expansion and resistance to therapy. We further show that these effects, at least in part, are attributed to changes in the composition of the TME. Using semi-conducting conjugated polymer nanoparticles designed to selectively disrupt microenvironment interactions with BTICs, we show a reduction in anti-apoptotic and proliferation markers and a decreased self-renewal in functional assays. In vitro and in vivo drug response assays reveal this combined approach sensitizes to standard of care Temozolomide. CONCLUSIONS: Our data reveals novel aspects of the TME that play an essential role in the biology of GBM and in resistance to therapy. We propose that this offers unique opportunities for drug targeting that may improve patient outcomes for this aggressive disease.

DIPG-11. DISSECTING THE DIFFUSE MIDLINE GLIOMA TUMOR MICROENVIRONMENT COMMUNICATIONS USING MULTI-OMICS APPROACHES

Abstract Diffuse midline glioma (DMG) represents a highly aggressive pediatric brain tumor with no chance of survival. Treatment options are urgently needed, and efforts have been put towards developing T-cell immunotherapy. However, this should consider DMG’s unique tumor microenvironment (TME), both in terms of anatomical location and developmental stage. To gain knowledge on this unique tumor niche, we implemented an immuno-competent, syngeneic mouse model based on in-utero electroporation (IUE) of the key driver mutations to induce tumor formation at an embryonic stage. We characterized DMG’s spatial and molecular landscape by combining snRNAseq, spatial transcriptomics, and state-of-the-art imaging. We observed a high intratumoral heterogeneity with spatially restricted cell populations. Importantly, their molecular profiles correlate with patient data, illustrating the clinical relevance of the IUE model. Analysis of cell-cell communications in the TME revealed novel signaling between DMG and immunosuppressive myeloid cells that could impact T-cell response. Using an advanced patient-derived DMG organoid co-culture model with macrophages and engineered T-cells, we are currently investigating the role of this pathway on T-cells mediated killing of DMG organoids. Thus, this project fills a critical need to delineate and overcome the immune-suppressive environment in DMG and potentiate T cell targeting.

Equine endometrial organoids treated with embryo-derived mesenchymal stem cell-secreted extracellular vesicles as a treatment for endometritis

A healthy uterine environment is essential for normal mare fertility and is critical for ensuring a positive financial return on breeding in the equine industry. Approximately 20% of Thoroughbred mares undergo persistent breeding-induced endometritis (PBIE), creating a uterine environment that is unfavorable for pregnancy. Despite extensive in vivo studies, the exact mechanisms causing endometritis and the most efficacious strategies for preventing or resolving PBIE are unknown. Organoids are physiologically-relevant 3D cell cultures that allow disease processes to be studied at the cellular level and eliminate confounding factors present in vivo. A potential therapeutic for PBIE is extracellular vesicles (EVs) secreted by embryo-derived mesenchymal stem cells (EDMSCs). EVs are lipid-bound nanoparticles containing proteins, mRNAs, and miRNAs that are naturally secreted by cells for intercellular communication. We hypothesized that EVs secreted by EDMSCs have anti-inflammatory properties to prevent PBIE. Our objectives were i) to assess EVs produced by EDMSCs for the presence of anti-inflammatory miRNAs via PCR and ii) to assess transfer of the anti-inflammatory miRNAs from EVs to endometrial organoids stimulated for inflammationwith frozen-killed sperm (FKS) or lipopolysaccharide (LPS). Results demonstrated the presence of reported anti-inflammatory miRNAs miR-10a, miR-21, miR-24, miR-145, and miR-146a in EVs secreted by three different EDMSC cell lines. Then, endometrial organoids (n=3 mares) were co-cultured with EDMSC EVs or PBS (control) for 24 h and subsequently exposed to two inflammatory stimuli (FKS or LPS). After 12h of exposure to inflammatory stimuli, organoids were washed and assessed for the presence of anti-inflammatory miRNAs by PCR (data was normalized using U6 snRNA). MiR-10a and miR-24 trended to be increased in organoids treated with EDMSC EVs compared to PBS controls in groups stimulated with either FKS or LPS. Furthermore, uptake of EVs by the organoids was corroborated by the co-culture of organoids with fluorescently-labelled (PKH26) EVs. EV uptake was confirmed by presence of a fluorescence signal in recipient organoid cells. While studies are ongoing, data suggests that EDMSC EVs contain anti-inflammatory miRNAs that may be delivered to endometrial cells to prevent PBIE in mares. Funding was provided by the Grayson-Jockey Club Research Foundation.

FRI-408 - Characterization of fibrogenesis in severe alcohol-related hepatitis using a 3D model of coculture of organoids and fibroblasts from patients

FRI-408 - Characterization of fibrogenesis in severe alcohol-related hepatitis using a 3D model of coculture of organoids and fibroblasts from patients

THU-252 - Human cytomegalovirus (HCMV) infection of macrophages induced abnormal development of cholangiocytes in an organoid co-culture model for biliary atresia

THU-252 - Human cytomegalovirus (HCMV) infection of macrophages induced abnormal development of cholangiocytes in an organoid co-culture model for biliary atresia

Modeling human ectopic pregnancies with trophoblast and vascular organoids

Ruptured ectopic pregnancy (REP), a pregnancy complication caused by aberrant implantation, deep invasion, and overgrowth of embryos in fallopian tubes, could lead to rupture of fallopian tubes and accounts for 4%-10% of pregnancy-related deaths. The lack of ectopic pregnancy phenotypes in rodents hampers our understanding of its pathological mechanisms. Here, we employed cell culture and organoid models to investigate the crosstalk between human trophoblast development and intravillous vascularization in the REP condition. Compared with abortive ectopic pregnancy (AEP), the size of REP placental villi and the depth of trophoblast invasion are correlated with the extent of intravillous vascularization. We identified a key pro-angiogenic factor secreted by trophoblasts, WNT2B, that promotes villous vasculogenesis, angiogenesis, and vascular network expansion in the REP condition. Our results reveal the important role of WNT-mediated angiogenesis and an organoid co-culture model for investigating intricate communications between trophoblasts and endothelial/endothelial progenitor cells.

Cytokine signaling converging on IL11 in ILD fibroblasts provokes aberrant epithelial differentiation signatures.

Interstitial lung disease (ILD) is a heterogenous group of lung disorders where destruction and incomplete regeneration of the lung parenchyma often results in persistent architectural distortion of the pulmonary scaffold. Continuous mesenchyme-centered, disease-relevant signaling likely initiates and perpetuates the fibrotic remodeling process, specifically targeting the epithelial cell compartment, thereby destroying the gas exchange area. With the aim of identifying functional mediators of the lung mesenchymal-epithelial crosstalk with potential as new targets for therapeutic strategies, we developed a 3D organoid co-culture model based on human induced pluripotent stem cell-derived alveolar epithelial type 2 cells that form alveolar organoids in presence of lung fibroblasts from fibrotic-ILD patients, in our study referring to cases of pulmonary fibrosis, as well as control cell line (IMR-90). While organoid formation capacity and size was comparable in the presence of fibrotic-ILD or control lung fibroblasts, metabolic activity was significantly increased in fibrotic-ILD co-cultures. Alveolar organoids cultured with fibrotic-ILD fibroblasts further demonstrated reduced stem cell function as reflected by reduced Surfactant Protein C gene expression together with an aberrant basaloid-prone differentiation program indicated by elevated Cadherin 2, Bone Morphogenic Protein 4 and Vimentin transcription. To screen for key mediators of the misguided mesenchymal-to-epithelial crosstalk with a focus on disease-relevant inflammatory processes, we used mass spectrometry and characterized the secretome of end stage fibrotic-ILD lung fibroblasts in comparison to non-chronic lung disease (CLD) patient fibroblasts. Out of the over 2000 proteins detected by this experimental approach, 47 proteins were differentially abundant comparing fibrotic-ILD and non-CLD fibroblast secretome. The fibrotic-ILD secretome profile was dominated by chemokines, including CXCL1, CXCL3, and CXCL8, interfering with growth factor signaling orchestrated by Interleukin 11 (IL11), steering fibrogenic cell-cell communication, and proteins regulating extracellular matrix remodeling including epithelial-to-mesenchymal transition. When in turn treating alveolar organoids with IL11, we recapitulated the co-culture results obtained with primary fibrotic-ILD fibroblasts including changes in metabolic activity. We identified mediators likely contributing to the disease-perpetuating mesenchymal-to-epithelial crosstalk in ILD. In our alveolar organoid co-cultures, we were able to highlight the importance of fibroblast-initiated aberrant epithelial differentiation and confirmed IL11 as a key player in fibrotic-ILD pathogenesis by unbiased fibroblast secretome analysis.

Co-cultures of colon cancer cells and cancer-associated fibroblasts recapitulate the aggressive features of mesenchymal-like colon cancer.

Poor prognosis in colon cancer is associated with a high content of cancer-associated fibroblasts (CAFs) and an immunosuppressive tumor microenvironment. The relationship between these two features is incompletely understood. Here, we aimed to generate a model system for studying the interaction between cancer cells and CAFs and their effect on immune-related cytokines and T cell proliferation. CAFs were isolated from colon cancer liver metastases and were immortalized to prolong lifespan and improve robustness and reproducibility. Established medium and matrix compositions that support the growth of patient-derived organoids were adapted to also support CAF growth. Changes in growth pattern and cellular re-organization were assessed by confocal microscopy, live cell imaging, and immunofluorescence. Single cell RNA sequencing was used to study CAF/organoid co-culture-induced phenotypic changes in both cell types. Conditioned media were used to quantify the production of immunosuppressive factors and to assess their effect on T cell proliferation. We developed a co-culture system in which colon cancer organoids and CAFs spontaneously organize into superstructures with a high capacity to contract and stiffen the extracellular matrix (ECM). CAF-produced collagen IV provided a basement membrane supporting cancer cell organization into glandular structures, reminiscent of human cancer histology. Single cell RNA sequencing analysis showed that CAFs induced a partial epithelial-to-mesenchymal-transition in a subpopulation of cancer cells, similar to what is observed in the mesenchymal-like consensus molecular subtype 4 (CMS4) colon cancer. CAFs in co-culture were characterized by high expression of ECM components, ECM-remodeling enzymes, glycolysis, hypoxia, and genes involved in immunosuppression. An expression signature derived from CAFs in co-culture identified a subpopulation of glycolytic myofibroblasts specifically residing in CMS1 and CMS4 colon cancer. Medium conditioned by co-cultures contained high levels of the immunosuppressive factors TGFβ1, VEGFA and lactate, and potently inhibited T cell proliferation. Co-cultures of organoids and immortalized CAFs recapitulate the histological, biophysical, and immunosuppressive features of aggressive mesenchymal-like human CRC. The model can be used to study the mechanisms of immunosuppression and to test therapeutic strategies targeting the cross-talk between CAFs and cancer cells. It can be further modified to represent distinct colon cancer subtypes and (organ-specific) microenvironments.

Novel model of cortical–meningeal organoid co-culture system improves human cortical brain organoid cytoarchitecture

Human cortical organoids (hCOs), derived from human induced pluripotent stem cells (iPSCs), provide a platform to interrogate mechanisms of human brain development and diseases in complex three- dimensional tissues. However, current hCO development methods lack important non-neural tissues, such as the surrounding meningeal layer, that have been shown to be essential for normal corticogenesis and brain development. Here, we first generated hCOs from a single rosette to create more homogenous organoids with consistent size around 250 µm by day 5. We then took advantage of a 3D co-culture system to encapsulate brain organoids with a thin layer of meningeal cells from the very early stages of cortical development. Immunostaining analysis was performed to display different cortical layer markers during different stages of development. Real-time monitoring of organoid development using IncuCyte displayed enhanced morphology and increased growth rate over time. We found that meningeal-encapsulated organoids illustrated better laminar organization by exhibiting higher expression of REELIN by Cajal–Retzius neurons. Presence of meningeal cells resulted in a greater expansion of TBR2 intermediate progenitor cells (IPCs), the deep cortical layer (CTIP2) and upper cortical layer (BRN2). Finally, meningeal-encapsulated organoids enhanced outer radial glial and astrocyte formation illustrated by stronger expression of HOPX and GFAP markers, respectively. This study presents a novel 3D co-culture platform to more closely mimic the in vivo cortical brain structure and enable us to better investigating mechanisms underlying the neurodevelopmental disorders during embryonic development.

Cryoablation inhibits the recurrence and progression of bladder cancer by enhancing tumour‐specific immunity

Recurrence and metastasis of bladder cancer are major factors affecting patient prognosis. Endoscopic cryoablation achieved a better clinical outcome among clinical patients and could be synergistic with ICIs. Thus, this study aimed to evaluate the immunological mechanism of cryoablation for bladder cancer to reveal the therapeutic mechanism. We systematically reviewed the clinical prognosis of patients underwent cryoablation at Huashan Hospital in these first-in-human studies (ChiCTR-INR-17013060). Murine models were constructed to explore cryoablation-induced tumour-specific immunity, which was further confirmed by primary bladder tumour organoids and autologous lymphocytes cocultured system. Cryoablation improved progression-free survival and recurrence-free survival respectively. Assessment of murine models after cryoablation confirmed microenvironment remodelling and tumour-specific T cells expansion. Enhanced antitumour effects were found after coculture of organoids with autologous lymphocytes collected from post-cryoablation. We also demonstrated cryoablation-induced tumour elimination required IFNGR expression on tumour cells. In addition, a long-lasting antitumour memory response is achieved by cryoablation and could be enhanced after combination with ICIs. This study revealed endoscopic cryoablation is an efficient and safe therapy for bladder tumour treatment. The tumour-specific immune responses induced by cryoablation could reduce tumour recurrence and metastasis.