Spheroid Culture Model Research Articles

Metformin-loaded chitosan nanoparticles augment silver nanoparticle-induced radiosensitization in breast cancer cells during radiation therapy

Recent research has focused on enhancing tumor response to radiation therapy using radiosensitizers to increase radiation absorption by cancerous tissues. This study utilized silver nanoparticles (AgNPs) as radiation sensitizers and chitosan as a nanocarrier to deliver metformin to breast cancer cells. Metformin-loaded chitosan nanoparticles (Met NPs) and AgNPs were synthesized and characterized. MCF-7 breast cancer cells were pretreated with Met NPs, followed by treatment with AgNPs and irradiation with X-rays at 2, 4, and 8 Gy doses. Cellular cytotoxicity, apoptosis, DNA damage, and 3D spheroid formation were evaluated. The synthesized Met NPs and AgNPs had average diameters of 51.5 ± 9.4 nm and 3.02 ± 0.03 nm, respectively. Cellular cytotoxicity assessment revealed the highest cytotoxicity in MCF-7 cells pretreated with Met NPs, treated with AgNPs, and irradiated with 8 Gy. Flow cytometry analysis demonstrated a 67.58 % apoptosis rate in cells pretreated with Met NPs, compared to 30.42 % in cells pretreated with plain metformin. DAPI staining revealed a 1.8-fold increase in DNA damage in cells pretreated with Met NPs and Ag NPs upon exposure to radiation. The 3D spheroid culture model confirmed a 60 % enhancement in the radiosensitivity of breast cancer cells in the presence of Met NPs and Ag NPs. The combination of Met NPs and Ag NPs represents a promising strategy to improve the therapeutic efficacy of radiation therapy for breast cancer treatment. The delivery of metformin can potentiate the radiosensitizing effects of Ag NPs, offering a novel approach to enhance cancer cells' response to radiation.

A Facile, Transfection-Free Approach to siRNA Delivery in In Vitro 3D Spheroid Models.

Cell culture has long been essential for preclinical modeling of human development and disease. However, conventional two-dimensional (2D) cell culture fails to faithfully model the complexity found in vivo, and novel drug candidates that show promising results in 2D models often do not translate to the clinic. More recently, three-dimensional (3D) cell culture models have gained popularity owing to their greater physiological relevance to in vivo biology. In particular, 3D spheroid models are becoming widely used due to their ability to mimic solid tumors, both in architecture and gradation of nutrients distributed from the outer, proliferative layers into the inner, quiescent layers of cells. Similar to in vivo tumors, cell lines grown in 3D spheroid models tend to be more resistant to antitumor drug treatments than their 2D cultured counterparts, though distinct signaling pathways and gene targets conferring this resistance have yet to be fully explored. RNA interference (RNAi) is an effective tool to elucidate gene function and discover novel druggable targets in 2D models; however, only a few studies have successfully performed RNAi in complex 3D models to date. Here, we demonstrate efficient RNAi-mediated knockdown using "transfection-free" Dharmacon Accell siRNAs in three spheroid culture models, in the presence or absence of the extracellular matrix. This methodology has the potential to be scaled up for complex arrayed screening experiments, which may aid in the identification of novel druggable targets with greater clinical relevance than those identified in 2D experiments. © 2024 Dharmacon, Inc. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Generation of 3D spheroids in matrix-free ULA plates Alternate Protocol 1: Generation of Matrigel matrix-embedded 3D spheroids Alternate Protocol 2: Generation of GrowDex hydrogel-embedded 3D spheroids Basic Protocol 2: Delivery of siRNA and collection of matrix-free 3D spheroids Alternate Protocol 3: Delivery of siRNA and collection of matrix-embedded spheroids Basic Protocol 3: RNA and protein extraction from spheroids for characterization of gene knockdown.

Human iPSC-derived liver co-culture spheroids to model liver fibrosis

The lack of adequate human in vitro models that recapitulate the cellular composition and response of the human liver to injury hampers the development of anti-fibrotic drugs. The goal of this study was to develop a human spheroid culture model to study liver fibrosis by using induced pluripotent stem cell (iPSC)-derived liver cells. iPSCs were independently differentiated towards hepatoblasts (iHepatoblasts), hepatic stellate cells (iHSCs), endothelial cells (iECs) and macrophages (iMΦ), before assembly into free floating spheroids by culturing cells in 96-well U-bottom plates and orbital shaking for up to 21 days to allow further maturation. Through transcriptome analysis, we show further maturation of iECs and iMΦ, the differentiation of the iHepatoblasts towards hepatocyte-like cells (iHeps) and the inactivation of the iHSCs by the end of the 3D culture. Moreover, these cultures display a similar expression of cell-specific marker genes (CYP3A4, PDGFRβ, CD31 and CD68) and sensitivity to hepatotoxicity as spheroids made using freshly isolated primary human liver cells. Furthermore, we show the functionality of the iHeps and the iHSCs by mimicking liver fibrosis through iHep-induced iHSC activation, using acetaminophen. In conclusion, we have established a reproducible human iPSC-derived liver culture model that can be used to mimic fibrosis in vitro as a replacement of primary human liver derived 3D models. The model can be used to investigate pathways involved in fibrosis development and to identify new targets for chronic liver disease therapy.

Dysfunctional natural killer cells can be reprogrammed to regain anti-tumor activity

Natural killer (NK) cells are critical to the innate immune system, as they recognize antigens without prior sensitization, and contribute to the control and clearance of viral infections and cancer. However, a significant proportion of NK cells in mice and humans do not express classical inhibitory receptors during their education process and are rendered naturally “anergic”, i.e., exhibiting reduced effector functions. The molecular events leading to NK cell anergy as well as their relation to those underlying NK cell exhaustion that arises from overstimulation in chronic conditions, remain unknown. Here, we characterize the “anergic” phenotype and demonstrate functional, transcriptional, and phenotypic similarities to the “exhausted” state in tumor-infiltrating NK cells. Furthermore, we identify zinc finger transcription factor Egr2 and diacylglycerol kinase DGKα as common negative regulators controlling NK cell dysfunction. Finally, experiments in a 3D organotypic spheroid culture model and an in vivo tumor model suggest that a nanoparticle-based delivery platform can reprogram these dysfunctional natural killer cell populations in their native microenvironment. This approach may become clinically relevant for the development of novel anti-tumor immunotherapeutic strategies.

Abstract 173: Studying the interaction between macrophages and solid stress in novel models of the tumor immune microenvironment

Abstract Glioblastoma (GBM) is one of the most aggressive forms of cancer, resisting conventional and immune-based therapies and typically killing patients within two years of diagnosis. This is largely due to the immunosuppressive GBM tumor microenvironment (TME), mediated in large part by tumor-resident macrophages. Macrophages’ role as immune regulators, as well as their sheer quantity in brain tumors, makes them attractive therapeutic targets. The GBM TME also features mechanical abnormalities. As a tumor grows, it expands into the surrounding brain, generating compressive solid stress. Macrophages can contribute to up to half of tumor mass and are known to respond to mechanical cues, allowing them to both contribute to and respond to solid stress, but this relationship has not yet been explored experimentally. To isolate the contribution of macrophages on solid stress, we incorporated RAW264.7 murine macrophages into agarose gels with varying stiffnesses. Over time, spheroids form as the cells proliferate. Because cells cannot alter agarose, cell aggregates must generate stress as they grow and displace the surrounding gel matrix. The resulting agarose-embedded spheroids were stained with calcein AM to observe spheroid viability and morphology. Using confocal microscopy and image processing, we obtained the final spheroid geometry and imported it into COMSOL to model the solid stress resulting from spheroid formation. Our initial experiments show that macrophages have distinct growth patterns dependent on the stiffness of their surrounding gel. At larger sizes, the spheroids adopt an ellipsoid shape and generate a distinct stress field compared to spheroidal shapes. To stimulate the solid stress that macrophages experience within a growing mass, we applied a custom weight to macrophages grown on a porous membrane. This applies 0.15 kPa of compressive solid stress, corresponding to the stress measured in murine glioma models. After 24 hours of compression, macrophages upregulate expression of both nitric oxide synthase and arginase-1, canonical M1 and M2 markers, respectively. This indicates that compression causes a more complex phenotype than can be described by the traditional M1/M2 axis, something that has been observed in tumor-associated macrophages. We also found an apparent difference in the fluorescence lifetime of compressed and uncompressed macrophages, indicating that compression alters macrophage metabolism. Both the spheroid and compression culture models are unique in the context of macrophages. This work will elucidate key pathways involved in myeloid “immunomechanics” and inform strategies to target the innate immune system in cancers such as GBM, as well as other immunological diseases. Citation Format: Alice Burchett, Saeed Siri, Hao Chen, Scott Howard, Meenal Datta. Studying the interaction between macrophages and solid stress in novel models of the tumor immune microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 173.

Abstract 4692: A novel ceramide synthase 2 agonist and its implication in triple-negative breast cancer therapy

Abstract Based on the biological/molecular markers, breast cancer can be classified into five subgroups: Luminal A (ER+/PR+/HER2-), Luminal B (ER+/PR-/HER2- or ER+/PR+/HER2+, triple-positive), ER-/PR-/HER2+, and ER-/PR-/HER2- (triple-negative). Significant progress has been made in treating hormone-responsive and HER2-expressing breast cancer. However, the targeted therapies are limited for triple-negative breast cancer (TNBC) due to lack of well-defined druggable targets. Additionally, all breast cancer subtypes can quickly develop resistance to current treatments. Thus, there is an urgent need for therapeutic strategies targeting pathways common to all subtypes, irrespective of receptor status. In this effort, we have synthesized a novel biisoquinoline-derivative, DH20931 (US Patent ID: US9914733B2) that induces cytotoxicity in breast cancer cells, including TNBC cells. The spatial molecular modeling and enzymatic assays show that DH20931 interacts with and stimulates ceramide synthase 2 (CerS2) activity, reduces the growth of hormone-responsive, HER2-expressing, and TNBC cells in monolayer and 3D spheroid culture models. DH20931 treatment increases the level of very long chain fatty acid (VLCFA) containing ceramides, induces lipotoxic endoplasmic reticulum (ER) stress, and ATF4/CHOP/PUMA pathway of apoptosis. Based on Swiss-ADME analysis, DH20931 possess all the properties of a druggable molecule and obeys the Lipinski-rule-of-five. Thus, DH20931 can be developed as a novel targeted therapeutic agent independent of ER, PR and HER2 status that potentially may reduce the morbidity and mortality for women with breast cancer. Citation Format: Hissah Alatawi, Nayeong Koo, Iqbal Mahmud, Haritha Nair, Amandeep Singh, Timothy J. Garrett, Arun K. Sharma, Sukwon Hong, Satya Narayan. A novel ceramide synthase 2 agonist and its implication in triple-negative breast cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4692.

Abstract 5287: Ex vivo pharmacologic inhibition of STAT3 effectively targets tumor and tumor associated suppressor cells in high-grade glioma 3D spheroids

Abstract Gliomas, a type of brain tumor originating from glial cells, comprise a heterogenous group of neoplasms. High-grade gliomas, in particular, present significant therapeutic challenges in the clinic. Unlike other solid tumors, the heterogenous glioma microenvironment is heavily enriched with tumor associated suppressor cells including myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs), which can account for 30-40% of the cellular composition1. These pro-tumorigenic myeloid cells are thought to contribute to the resistance of glioma to immunotherapy. Efforts to target the suppressive nature of these dominating cell types are in development to yield more therapeutic options for patients with these devastating diseases. Constitutive activation of STAT3 in gliomas has been associated with increased tumor progression and reduced immune response. We have observed in other cancer models that a phenotypic switch occurs from STAT3 pathway activation in 3D spheroid culture to STAT3 inactivation when cultured in 2D. Therefore, we sought to determine the role of STAT3 activation and its role in the interplay between glioma and their immune suppressive environment using a 3D spheroid model. We modified our commercially available test platform, 3D-Predict™ Glioma, such that it is conducive to monitoring immune cell function. Newly diagnosed treatment naive primary samples from HGG patients were dissociated and cryogenically preserved and banked. Samples were profiled for the abundance of tumor associated suppressive myeloid cells using flow cytometry. We determined that relative proportions of tumor suppressor cells were detectable and varied across HGG primary patient samples with TAMs being the predominate immune cell type identified. Pro-tumorigenic TAM markers including CD163 and CD206 were correlated with temozolomide response and were associated with poor patient prognosis. When we evaluated the role of p-STAT in HGG primary samples, p-STAT was detected at baseline and abundance was related back to the presence of tumor associated immune suppressor cells. The impact of STAT3 signaling blockade by the inhibitor WP1066 was determined ex vivo, and efficacy was related back to MGMT promotor methylation status and patient clinical outcome. We detected shifts in cytokine signatures following treatment of HGG 3D spheroid models with WP1066 which are known to target tumor associated suppressor cell functions. This work demonstrates the critical role suppressive immune cells play in HGG clinical response. Given p-STAT can be altered in 2D culture compared to 3D culture, ex vivo therapeutic response profiling of HGG samples is necessary using the more physiologically relevant spheroid culture model. 1.Hambardzumyan et al. The role of microglia and macrophages in glioma maintenance and progression. Nat. Neurosci. 19, 20-27 (2016). Citation Format: Katy A. Lassahn, Ashley K. Elrod, Teresa M. DesRochers, Kathryn M. Appleton. Ex vivo pharmacologic inhibition of STAT3 effectively targets tumor and tumor associated suppressor cells in high-grade glioma 3D spheroids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5287.

Comparison of Minced Cartilage Implantation with Autologous Chondrocyte Transplantation in an In Vitro Inflammation Model.

The current gold standard to treat large cartilage defects is autologous chondrocyte transplantation (ACT). As a new surgical method of cartilage regeneration, minced cartilage implantation (MCI) is increasingly coming into focus. The aim of this study is to investigate the influence of chondrogenesis between isolated and cultured chondrocytes compared to cartilage chips in a standardized inflammation model with the proinflammatory cytokine TNFα. Articular chondrocytes from bovine cartilage were cultured according to the ACT method to passage 3 and transferred to spheroid culture. At the same time, cartilage was fragmented (<1 mm3) to produce cartilage chips. TNFα (20 ng/mL) was supplemented to simulate an inflammatory process. TNFα had a stronger influence on the passaged chondrocytes compared to the non-passaged ones, affecting gene expression profiles differently between isolated chondrocytes and cartilage chips. MCI showed less susceptibility to TNFα, with reduced IL-6 release and less impact on inflammation markers. Biochemical and histological analyses supported these findings, showing a greater negative influence of TNFα on the passaged pellet cultures compared to the unpassaged cells and MCI constructs. This study demonstrated the negative influence of TNFα on chondrogenesis in a chondrocyte spheroid culture and cartilage fragment model. Passaged chondrocytes are more sensitive to cytokine influences compared to non-passaged cells and chondrons. This suggests that MCI may have superior regeneration potential in osteoarthritic conditions compared to ACT. Further investigations are necessary for the translation of these findings into clinical practice.

Kynurenine 3-monooxygenase limits de novo NAD+ synthesis through dietary tryptophan in renal proximal tubule epithelial cell models.

Nicotinamide adenine dinucleotide (NAD+) is a pivotal coenzyme, essential for cellular reactions, metabolism, and mitochondrial function. Depletion of kidney NAD+ levels and reduced de novo NAD+ synthesis through the tryptophan-kynurenine pathway are linked to acute kidney injury (AKI), whereas augmenting NAD+ shows promise in reducing AKI. We investigated de novo NAD+ biosynthesis using in vitro, ex vivo, and in vivo models to understand its role in AKI. Two-dimensional (2-D) cultures of human primary renal proximal tubule epithelial cells (RPTECs) and HK-2 cells showed limited de novo NAD+ synthesis, likely due to low pathway enzyme gene expression. Using three-dimensional (3-D) spheroid culture model improved the expression of tubular-specific markers and enzymes involved in de novo NAD+ synthesis. However, de novo NAD+ synthesis remained elusive in the 3-D spheroid culture, regardless of injury conditions. Further investigation revealed that 3-D cultured cells could not metabolize tryptophan (Trp) beyond kynurenine (KYN). Intriguingly, supplementation of 3-hydroxyanthranilic acid into RPTEC spheroids was readily incorporated into NAD+. In a human precision-cut kidney slice (PCKS) ex vivo model, de novo NAD+ synthesis was limited due to substantially downregulated kynurenine 3-monooxygenase (KMO), which is responsible for KYN to 3-hydroxykynurenine conversion. KMO overexpression in RPTEC 3-D spheroids successfully reinstated de novo NAD+ synthesis from Trp. In addition, in vivo study demonstrated that de novo NAD+ synthesis is intact in the kidney of the healthy adult mice. Our findings highlight disrupted tryptophan-kynurenine NAD+ synthesis in in vitro cellular models and an ex vivo kidney model, primarily attributed to KMO downregulation.NEW & NOTEWORTHY Nicotinamide adenine dinucleotide (NAD+) is essential in regulating mitochondrial function. Reduced NAD+ synthesis through the de novo pathway is associated with acute kidney injury (AKI). Our study reveals a disruption in de novo NAD+ synthesis in proximal tubular models, but not in vivo, attributed to downregulation of enzyme kynurenine 3-monooxygenase (KMO). These findings highlight a crucial role of KMO in governing de novo NAD+ biosynthesis within the kidney, shedding light on potential AKI interventions.

Development of adrenal 3-dimensional spheroid cultures: potential for the treatment of adrenal insufficiency and neurodegenerative diseases

Aim: Regenerative and curative strategies would be desirable for neurodegenerative and adrenal diseases, and multipotent adrenal stem cells are considered as promising biological tools for this purpose. Stem-like cells with the potential to proliferate and differentiate in vivo and in vitro were discovered in both cortex and medulla of the adrenal gland. Previously, it was demonstrated that nestin-positive progenitors in the cortex and medulla, play an important role under stress. In the present study, the cultivation of these cells was optimized and their growth in vitro was characterized. Methods: Primary cells from the adrenal cortex and medulla from Nes-GFP mice were isolated and the in vitro culture conditions promoting the growth of stem and progenitor cells using different 3-dimensional (3D) spheroid culture models were optimized. Results: Both cortical and medullary cells could be cultured for at least one month under several different low-adherence conditions maintaining their viability and potential to differentiate. Medullary cells grew faster than cortical cells. Endothelin did not affect the cultures. Conclusions: Adrenomedullary and adrenocortical nestin-positive progenitor cells can be cultured long-term in 3D cultures maintaining their proliferation and differentiation capabilities. Such multidimensional models can potentially be used for drug screening to develop personalized medicines or for transplantation to treat neurodegenerative disorders or adrenal diseases, such as adrenal insufficiency.

Physicochemical and Biopharmaceutical Controllability of New Self-Assembled Fatty Acid Conjugated Leuprolide for the Enhanced Anticancer Activity.

Leuprolide (LEU), a synthetic nonapeptide analog of naturally occurring gonadotropin-releasing hormone (GnRH), could exert a direct inhibitory activity on the proliferation of prostate cancer cells. However, the short half-life in blood and the biopharmaceutical problem of LEU limit this anticancer activity. To improve its druggability for improving anticancer activity, the amine-group targeted LEU was conjugated with different chain lengths of saturated fatty acids (FAs). LEU-fatty acid conjugates (LFCs) were synthesized by exploiting N-hydroxysuccinimidyl (NHS) conjugation chemistry. The physicochemical properties and the self-assembled behaviors of the conjugates were extensively investigated. The in vitro anticancer activity of three LFCs was extensively studied in both 2D monolayer and 3D spheroid culture models of a prostate cancer cell line, PC3. Three LFCs could be readily self-assembled into nanoparticles (LFNs) with a small size of around 100 nm, positive charges, and exhibited greater permeability rates compared to the same concentration of LEU, excluding LSN. The chain length of FA in conjugate was positively related to the selectivity index between cancer cells and non-cancerous cell lines. All LFCs showed a superior direct antiproliferative effect on cancer cells in the following order: LSC (98.9%) > LPC (86.7%) > LLC (75.0%) > LEU (8.9%) after repeat daily of the same dose strength of LEU for 4 days. In addition, the 3D spheroid model study indicates that all LFCs with a one-time treatment performed a long-acting inhibitory effect on tumor growth as compared to LEU after 7 days. The conjugation of LEU with different chain lengths of FAs could provide a novel strategy to improve peptide stability and exert an additional superior direct inhibitory effect for the treatment of several hormone-responsive tumor systems using therapeutic peptides.

Fabrication of a Low-Cost Microfluidic Device for High-Throughput Drug Testing on Static and Dynamic Cancer Spheroid Culture Models

Drug development is a complex and expensive process from new drug discovery to product approval. Most drug screening and testing rely on in vitro 2D cell culture models; however, they generally lack in vivo tissue microarchitecture and physiological functionality. Therefore, many researchers have used engineering methods, such as microfluidic devices, to culture 3D cells in dynamic conditions. In this study, a simple and low-cost microfluidic device was fabricated using Poly Methyl Methacrylate (PMMA), a widely available material, and the total cost of the completed device was USD 17.75. Dynamic and static cell culture examinations were applied to monitor the growth of 3D cells. α-MG-loaded GA liposomes were used as the drug to test cell viability in 3D cancer spheroids. Two cell culture conditions (i.e., static and dynamic) were also used in drug testing to simulate the effect of flow on drug cytotoxicity. Results from all assays showed that with the velocity of 0.005 mL/min, cell viability was significantly impaired to nearly 30% after 72 h in a dynamic culture. This device is expected to improve in vitro testing models, reduce and eliminate unsuitable compounds, and select more accurate combinations for in vivo testing.

Abstract 3200: Non-engineered T cells with specific anticancer effects in KRAS-mutated colorectal cancer

Abstract Cytokine-induced killer (CIK) cell therapy is known as a useful treatment for cancer immunotherapy due to its anticancer activity and safety. However, its clinical efficacy is limited due to its lack of antigen specificity and low in vivo persistence. KRAS mutations play an important role in promoting tumorigenesis in cancer. But, its clinical application as a biomarker for cancer treatment is still difficult. Non-engineered T cell therapy approaches could be a promising strategy for treating KRAS-mutated cancer. Herein we developed non-engineered T cells empowered with specific anticancer effects in KRAS-mutated colorectal cancer (CRC), and investigated its properties and anticancer effects compared to CIK cells. A recombinant overlapping peptide was designed to overlap the KRAS protein by 15 amino acids linked by a cathepsin S cleavage site (LRMK). It contained KRASG12D, KRASG12V, KRASG13D, and KRASWT epitope peptides and other KRAS protein regions. Peripheral blood mononuclear cells (PBMCs) from CRC patients with KRAS mutations were stimulated with the recombinant overlapping peptides in vitro for two days in the presence of interleukin (IL)-4, granulocyte-macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor (TNF)-α, IL-1β, and prostaglandin 2, and expanded using the 12-day CIK cell expansion method in the presence of IL-2 (200 IU/mL). To verify the enrichment of KRAS mutant-specific T cells, the expanded T cells were restimulated by pulsed monocyte-derived dendritic cells with KRAS mutant antigen for two days and the frequency of KRAS mutation-specific T cells was determined using the interferon (INF)-γ capture assay. Red fluorescent protein (RFP)-expressing HLA-matched cell lines and cell line-derived spheroids T3M10 (KRASG12D) and MCF-7 (KRASWT) were used for the Incucyte immune cell killing assay. T-cell phenotypes were determined by flow cytometry. The expanded non-engineered T cells stimulated with KRAS mutant antigen showed skewed CD4 T cell differentiation and increased central memory T cells compared to CIK cells, suggesting that they may have more long-term immunity and functionality than CIK cells. The KRASG12D-specific T cells were enriched 12-13% (9.4-fold) by in vitro stimulation compared to 1.3% in CIK cells. Anticancer activity in a 2D-culture model was significantly higher in KRASG12D-specific enriched T cells (82.5%) than in CIK cells (64.9%) co-cultured with T3M10 cells for 48 h. In a 3D spheroid-culture model, increased cytotoxicity was also detectable in the KRASG12D-specific enriched T cells (13.2% at 72 h and 14.1% at 142 h) compared to CIK cells. These results demonstrated that non-engineered T cells with KRAS mutated-specific anticancer activity are an ideal candidate for KRAS mutant cancer-targeted immunotherapy. Further studies are necessary to verify the anticancer effects in vivo. Citation Format: Sunki Lim, Yujeong Gho, Seoyoung Kim, Min Ki Kim, Jong Seob Park, Wang Jun Lee, Young-Kwan Lee, Hyoun Jong Moon, Excelsisbio.Inc, Goyang, Korea. Non-engineered T cells with specific anticancer effects in KRAS-mutated colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3200.

Evaluation of Anticancer Activity of Zhubech, a New 5-FU Analog Liposomal Formulation, against Pancreatic Cancer.

Pancreatic cancer is projected to be the second leading cause of cancer-related death by 2030 in the US. The benefits of the most common systemic therapy for various pancreatic cancers have been masked by high drug toxicities, adverse reactions, and resistance. The use of nanocarriers such as liposomes to overcome these unwanted effects has become very popular. This study aims to formulate 1,3-bistertrahydrofuran-2yl-5FU (MFU)-loaded liposomal nanoparticles (Zhubech) and to evaluate itsstability, release kinetics, in vitro and in vivo anticancer activities, and biodistribution in different tissues. Particle size and zeta potential were determined using a particle size analyzer, while cellular uptake of rhodamine-entrapped liposomal nanoparticles (Rho-LnPs) was determined by confocal microscopy. Gadolinium hexanoate (Gd-Hex) was synthesized and entrapped into the liposomal nanoparticle (LnP) (Gd-Hex-LnP), as a model contrast agent, to evaluate gadolinium biodistribution and accumulation by LnPs in vivo using inductively coupled plasma mass spectrometry (ICP-MS). The mean hydrodynamic diameters of blank LnPs and Zhubech were 90.0 ± 0.65 nm and 124.9 ± 3.2 nm, respectively. The hydrodynamic diameter of Zhubech was found to be highly stable at 4 °C and 25 °C for 30 days in solution. In vitro drug release of MFU from Zhubech formulation exhibited the Higuchi model (R2 value = 0.95). Both Miapaca-2 and Panc-1 treated with Zhubech showed reduced viability, two- or four-fold lower than that of MFU-treated cells in 3D spheroid (IC50Zhubech = 3.4 ± 1.0 μM vs. IC50MFU = 6.8 ± 1.1 μM) and organoid (IC50Zhubech = 9.8 ± 1.4 μM vs. IC50MFU = 42.3 ± 1.0 μM) culture models. Confocal imaging confirmed a high uptake of rhodamine-entrapped LnP by Panc-1 cells in a time-dependent manner. Tumor-efficacy studies in a PDX bearing mouse model revealed a more than 9-fold decrease in mean tumor volumes in Zhubech-treated (108 ± 13.5 mm3) compared to 5-FU-treated (1107 ± 116.2 mm3) animals, respectively. This study demonstrates that Zhubech may be a potential candidate for delivering drugs for pancreatic cancer treatment.

Experimental in vitro, exvivo and in vivo models in prostate cancer research.

Androgen deprivation therapy has a central role in the treatment of advanced prostate cancer, often causing initial tumour remission before increasing independence from signal transduction mechanisms of the androgen receptor and then eventual disease progression. Novel treatment approaches are urgently needed, but only a fraction of promising drug candidates from the laboratory will eventually reach clinical approval, highlighting the demand for critical assessment of current preclinical models. Such models include standard, genetically modified and patient-derived cell lines, spheroid and organoid culture models, scaffold and hydrogel cultures, tissue slices, tumour xenograft models, patient-derived xenograft and circulating tumour cell eXplant models as well as transgenic and knockout mouse models. These models need to account for inter-patient and intra-patient heterogeneity, the acquisition of primary or secondary resistance, the interaction of tumour cells with their microenvironment, which make crucial contributions to tumour progression and resistance, as well as the effects of the 3D tissue network on drug penetration, bioavailability and efficacy.

38P Hormonal modulation of photodynamic therapy efficacy in breast cancer 3D spheroid culture model

Most preclinical cancer treatment studies focus on the investigation on monolayer cancer cells. However, there are significant differences in cell characteristics between monolayer cells and solid tumors, thus limiting the potential efficacy of in vitro Photodynamic Therapy (PDT) studies. Hence, PDT studies on 3D spheroids might provide insights in hormonal microenvironment. This study aims to elucidate the efficacy of hexyl-aminolaevulinic acid (H-ALA) mediated PDT on 3D spheroids in hormonal simulated microenvironment.

Physiological Mineralization during In Vitro Osteogenesis in a Biomimetic Spheroid Culture Model.

Bone health-targeting drug development strategies still largely rely on inferior 2D in vitro screenings. We aimed at developing a scaffold-free progenitor cell-based 3D biomineralization model for more physiological high-throughput screenings. MC3T3-E1 pre-osteoblasts were cultured in α-MEM with 10% FCS, at 37 °C and 5% CO2 for up to 28 days, in non-adherent V-shaped plates to form uniformly sized 3D spheroids. Osteogenic differentiation was induced by 10 mM β-glycerophosphate and 50 µg/mL ascorbic acid. Mineralization stages were assessed through studying expression of marker genes, alkaline phosphatase activity, and calcium deposition by histochemistry. Mineralization quality was evaluated by Fourier transformed infrared (FTIR) and scanning electron microscopic (SEM) analyses and quantified by micro-CT analyses. Expression profiles of selected early- and late-stage osteoblast differentiation markers indicated a well-developed 3D biomineralization process with strongly upregulated Col1a1, Bglap and Alpl mRNA levels and type I collagen- and osteocalcin-positive immunohistochemistry (IHC). A dynamic biomineralization process with increasing mineral densities was observed during the second half of the culture period. SEM–Energy-Dispersive X-ray analyses (EDX) and FTIR ultimately confirmed a native bone-like hydroxyapatite mineral deposition ex vivo. We thus established a robust and versatile biomimetic, and high-throughput compatible, cost-efficient spheroid culture model with a native bone-like mineralization for improved pharmacological ex vivo screenings.

Cytotoxic effect of metformin on butyrate-resistant PMF-K014 colorectal cancer spheroid cells

Three-dimensional (3D) cell culture models are used in cancer research because they mimic physiological responses in vivo compared with two-dimensional (2D) culture systems. Recently, cross-resistance of butyrate-resistant (BR) cells and chemoresistance in colorectal cancer (CRC) cells have been reported; however, effective treatments for BR cells have not been identified. In this study, we investigated the cytotoxicity of metformin (MET), an anti-diabetic drug, on BR CRC cells in a 3D spheroid culture model. The results demonstrate that MET decreases spheroid size, migration, and spheroid viability, while it increases spheroid death. The molecular mechanism revealed that AMP-activated protein kinase (AMPK) and Akt serine/threonine kinase 1(Akt) were significantly upregulated, whereas the acetyl-CoA-carboxylase (ACC) and mammalian target of rapamycin (mTOR) were downregulated, which led to caspase activation and apoptosis. Our findings show the potential cytotoxicity of MET on CRC-BR cells. The combination of MET and conventional chemotherapeutic drugs should be addressed in further studies to reduce the side effects of standard chemotherapy for CRC.

Spheroid culture models adequately imitate distinctive features of the renal cancer or melanoma microenvironment.

Tumor development studies should adapt to cancer cells' specific mechanisms in connection with their microenvironment. Standard two-dimensional cultures and gas composition are not relevant to the real cancer environment. Existing three-dimensional models are often requiring sophisticated conditions. Here, we propose and characterize, in two cancer models, melanoma (B16F10) and kidney cancer (RenCa), a three-dimensional culture method, reporting the presence of hypoxia-related genes/proteins and aggressiveness mechanisms (epithelial mesenchymal transition and cancer stem cells). We validate the designed three-dimensional method by comparing it with in vivo growing tumors. The developed method brings simplicity and data reproducibility. Melanoma spheroid-growing cells reached a cell cycle arrest at the G0/G1 phase and showed induction of hypoxia. Spheroid-recovered RenCa cells were enriched in proliferating cells and displayed delayed hypoxia. Moreover, the responses to hypoxia observed in spheroids were validated by in vivo tumor studies for both lines. Three-dimensional shapes induced cancer stem cells in renal cancer, whereas epithelial to mesenchymal transition occurred in the melanoma model. Such distinction in the use of different aggressiveness-leading pathways was observed in in vivo melanoma vs kidney tumors. Thus, this 3D culture model approach is adequate to uncover crucial molecular pathways using distinct mechanisms to reach aggressiveness; i.e., B16F10 cells perform epithelial to mesenchymal transition while RenCa cells dedifferentiate into cancer stem cells. Such three-dimensional models help mimic the in vivo tumor features, i.e., hypoxia and aggressiveness mechanisms as validated here by next-generation sequencing analysis, and are proposed for further alternative methods to in vivo studies.

Short-term tetrabromobisphenol A exposure promotes fibrosis of human uterine fibroid cells in a 3D culture system through TGF-beta signaling.

Tetrabromobisphenol A (TBBPA), a derivative of BPA, is a ubiquitous environmental contaminant with weak estrogenic properties. In women, uterine fibroids are highly prevalent estrogen‐responsive tumors often with excessive accumulation of extracellular matrix (ECM) and may be the target of environmental estrogens. We have found that BPA has profibrotic effects in vitro, in addition to previous reports of the in vivo fibrotic effects of BPA in mouse uterus. However, the role of TBBPA in fibrosis is unclear. To investigate the effects of TBBPA on uterine fibrosis, we developed a 3D human uterine leiomyoma (ht‐UtLM) spheroid culture model. Cell proliferation was evaluated in 3D ht‐UtLM spheroids following TBBPA (10−6–200 µM) administration at 48 h. Fibrosis was assessed using a Masson's Trichrome stain and light microscopy at 7 days of TBBPA (10−3 µM) treatment. Differential expression of ECM and fibrosis genes were determined using RT² Profiler™ PCR arrays. Network and pathway analyses were conducted using Ingenuity Pathway Analysis. The activation of pathway proteins was analyzed by a transforming growth factor‐beta (TGFB) protein array. We found that TBBPA increased cell proliferation and promoted fibrosis in 3D ht‐UtLM spheroids with increased deposition of collagens. TBBPA upregulated the expression of profibrotic genes and corresponding proteins associated with the TGFB pathway. TBBPA activated TGFB signaling through phosphorylation of TGFBR1 and downstream effectors—small mothers against decapentaplegic ‐2 and ‐3 proteins (SMAD2 and SMAD3). The 3D ht‐UtLM spheroid model is an effective system for studying environmental agents on human uterine fibrosis. TBBPA can promote fibrosis in uterine fibroid through TGFB/SMAD signaling.