The CAM Model-Q&A with Experts

Oncolytic virotherapy provides a potent therapy option for squamous bladder cancer

Prognosis for squamous cell carcinoma (SCC) of the bladder is limited mostly because of lack of effective treatment regimens. Oncolytic virotherapy represents a promising option for bladder cancer and received in 2024 FDA therapy designation for the treatment of non-invasive high-grade bladder cancer (BLCA). For muscle-invasive bladder cancer (MIBC), preclinical studies demonstrated high efficacy of the oncolytic adenovirus XVir-N-31 in urothelial carcinoma (UC). We analyzed the potency of XVir-N-31 virotherapy as a novel treatment option in SCC. Replication of XVir-N-31 has been described to be facilitated by high expression level of Y-Box binding protein 1 (YB-1). Increased YB-1-mRNA expression was detected in basal/squamous subtype in TCGA BLCA cohort compared to urothelial and luminal BLCA and correlated with patient outcomes. Furthermore, immunohistochemical staining of 89 SCC on a tissue microarray confirmed strong YB-1 expression in squamous BLCA (sq-BLCA). In vitro, XVir-N-31 showed in subtype-specific cell cultures high rates of infection, replication and cell-killing capacity. In a novel in ovo xenograft model, XVir-N-31 impaired growth of xenografts of patient-derived ex vivo cell lines (p-SCC, p-UC) with growth suppression rates of 39-49%. We provide preclinical evidence ex vivo and in ovo for high efficacy of XVir-N-31 based oncolytic virotherapy as novel SCC therapy.

The Chicken Embryo: An Alternative Animal Model in Development, Disease and Pharmacological Treatment

To examine various medications and substances, in vivo models such as rats and mice are routinely used. However, it is utterly desirable to reduce extensive amounts of animals for these experimental models, which are costly and time-consuming. Animals are frequently put through a variety of procedures that could cause them pain, distress, or even harm; therefore, it is important to think about the ethical ramifications of using them in research. Thus, by following the three R's of animal research: reduction, replacement, and refinement, living animals used in studies should be minimized. The embryo of Gallus gallus, the domestic chicken, is a great model to research many different diseases and conditions. Its efficient blood supply from the chorioallantoic membrane gives us a unique possibility to administer chemicals or cells to the embryo in a noninvasive manner. In this review, we evaluate some advantages and disadvantages of using the developing chicken as an alternative in vivo model for development, disease, and pharmacological treatment. We focus on the top two leading causes of death: neurological disorders and cancer. We present a number of studies that describe the use of the chicken embryo in neuroscience and neurodevelopment research, in cancer research, and pharmacodynamic and pharmacokinetic studies. These studies show that the chicken embryo is an inexpensive, readily available, self-sufficient model with a short incubation period, high accessibility, and ideal for drug screening, making it an appealing model that can provide insightful biological and pharmacological information.

Functionalized Cerium Oxide Nanoparticles Enhance Penetration into Melanoma Spheroids In Vivo through Angiogenesis

Angiogenesis is a crucial step in tumor progression, including melanoma, making anti-angiogenic strategies a widely explored treatment approach. However, both innate and acquired resistance to these therapies suggest that this approach may need re-evaluation. Nanoparticles have gained attention for their potential to enhance drug delivery and retention within tumors via the bloodstream. However, the in vitro screening of nanoparticles is limited by the inability of preclinical models to replicate the complex tumor microenvironment, especially the blood supply. Here, it is demonstrated that melanoma cells embedded in Matrigel spheroids can engraft in and be vascularized by the chorioallantoic membrane (CAM) of fertilized chicken eggs. This model allows for the assessment of nanoparticle toxicity and accumulation in tumor spheroids, as well as functional effects such as angiogenesis. Cerium oxide nanoparticles (nanoceria) and their surface functionalized derivatives are widely explored for biomedical applications due to their ability to modulate oxidative stress and angiogenesis. Here, it is observed that heparin functionalized nanoceria penetrate melanoma spheroids in the CAM and promote spheroid vascularization to a greater extent than nanoceria alone. This study aids in the development of preclinical cancer models for nanoparticle screening and provides new insight into the interplay between nanoparticle surface coatings and biological effects.

Evaluation of tumor-colonizing Salmonella strains using the chick chorioallantoic membrane model

The chick embryo chorioallantoic membrane (CAM) tumor model is a valuable preclinical model for studying the tumor-colonizing process of Salmonella enterica serovar Typhimurium. It offers advantages such as cost-effectiveness, rapid turnaround, reduced engraftment issues, and ease of observation. In this study, we explored and validated the applicability of the partially immune-deficient CAM tumor model. Herein, we demonstrate that Salmonella preferentially colonizes tumors and directly causes tumor cell death. Bacterial migration, tumor colonization, and intra-tumor distribution did not require flagellar-mediated motility. The vast majority of Salmonella that colonized the CAM tumor were extracellular. Thus, tumor invasion was independent of both Salmonella pathogenicity island-1-encoded and Salmonella pathogenicity island-2-encoded type III secretion systems. Surprisingly, the extracellular residence of Salmonella on CAM tumors did not require biofilm formation. We evaluated our wild-type parental strain compared to the attenuated clinical strain VNP20009 and discovered a reduced tumor colonization capability of VNP20009. The inability to effectively colonize CAM tumors potentially explains the reduced anti-tumor efficacy of VNP20009. Our work establishes the xenograft CAM model as an informative and predictive screening platform for studying tumor-colonizing Salmonella.IMPORTANCECancer has a major impact on society, as it poses a significant health burden to human populations worldwide. Salmonella Typhimurium has demonstrated promise in cancer treatment by exerting direct tumoricidal effects and enhancing host-mediated anti-tumor immunity in xenograft mouse studies. A general understanding of its pathogenesis and the relative ease of genetic manipulation support the development of attenuated strains for therapeutic use. Alternative in ovo models, such as the chorioallantoic membrane tumor model, present a suitable screening platform to accelerate the development of therapeutic strains. It allows for rapid evaluation of Salmonella strains to assess their efficacy and potential as oncolytic agents. The present study establishes that the in ovo tumor model can be utilized as a preclinical tool for evaluating oncolytic Salmonella, bridging the gap between in vitro and in vivo screening.

Exploring the landscape of current in vitro and in vivo models and their relevance for targeted radionuclide theranostics

Cancer remains a leading cause of mortality globally, driving ongoing research into innovative treatment strategies. Preclinical research forms the base for developing these novel treatments, using both in vitro and in vivo model systems that are, ideally, as clinically representative as possible. Emerging as a promising approach for cancer management, targeted radionuclide theranostics (TRT) uses radiotracers to deliver (cytotoxic) radionuclides specifically to cancer cells. Since the field is relatively new, more advanced preclinical models are not yet regularly applied in TRT research. This narrative review examines the currently applied in vitro, ex vivo and in vivo models for oncological research, discusses if and how these models are now applied for TRT studies, and whether not yet applied models can be of benefit for the field. A selection of different models is discussed, ranging from in vitro two-dimensional (2D) and three-dimensional (3D) cell models, including spheroids, organoids and tissue slice cultures, to in vivo mouse cancer models, such as cellline-derived models, patient-derived xenograft models and humanized models. Each of the models has advantages and limitations for studying human cancer biology, radiopharmaceutical assessment and treatment efficacy. Overall, there is a need to apply more advanced models in TRT research that better address specific TRT phenomena, such as crossfire and abscopal effects, to enhance the clinical relevance and effectiveness of preclinical TRT evaluations.

Pharmacological effects of osimertinib on a chicken chorioallantoic membrane xenograft model with the EGFR exon-19-deleted advanced NSCLC mutation

Non-small cell lung cancer (NSCLC) affects 10-50% of patients with epidermal growth factor receptor (EGFR) mutations. Osimertinib is a third-generation EGFR tyrosine kinase inhibitor (TKI) that radically changes the outcome of patients with tumors bearing EGFR sensitizing or EGFR T790M resistance mutations. However, resistance usually occurs, and new therapeutic combinations need to be explored. The chorioallantoic membrane (CAM) xenograft model is ideal for studying aggressive tumor growth and the responses to complex therapeutic combinations due to its vascularization and complex microenvironment. This study aims to demonstrate the relevance of analyzing a complex therapeutic response to osimertinib treatment, especially through advanced transcriptomic analysis with the CAM model, which has been limited thus far. We engrafted HCC827 cells (EGFR p.E746_A750del) into the CAM model and treated them with various osimertinib doses for 7 days. The study involved supervised multivariate discrimination and ontology analysis of human transcriptional data. We found that CDX tumor growth inversely correlated with osimertinib dosage, with a notable 35% tumor weight reduction at 10 μm. Transcriptomic analysis revealed that osimertinib reduces EGFR pathway activity and its effectors, and dampens chemotaxis, immune recruitment and angiogenesis, indicating that effectiveness extends beyond cellular mechanisms to the tissue level. This was supported by a 15% reduction in blood vessels around the xenograft in osimertinib-treated cases. This study is the first to demonstrate that ontological analysis of transcriptomic data in the CAM model aligns with clinical observations, highlighting the relevance of this methodology for understanding and ameliorating the efficacy of targeted therapy in NSCLC.

A bioconvergence study on platinum-free concurrent chemoradiotherapy for the treatment of HPV-negative head and neck carcinoma

Locally advanced head and neck squamous cell carcinoma (LA-HNSCC) is characterized by high rate of recurrence, resulting in a poor survival. Standard treatments are associated with significant toxicities that impact the patient's quality of life, highlighting the urgent need for novel therapies to improve patient outcomes. On this regard, noble metal nanoparticles (NPs) are emerging as promising agents as both drug carriers and radiosensitizers. On the other hand, co-treatments based on NPs are still at the preclinical stage because of the associated metal-persistence.In this bioconvergence study, we introduce a novel strategy to exploit tumour chorioallantoic membrane models (CAMs) in radio-investigations within clinical equipment and evaluate the performance of non-persistent nanoarchitectures (NAs) in combination with radiotherapy with respect to the standard concurrent chemoradiotherapy for the treatment of HPV-negative HNSCCs. A comparable effect has been observed between the tested approaches, suggesting NAs as a potential platinum-free agent in concurrent chemoradiotherapy for HNSCCs. On a broader basis, our bioconvergence approach provides an advance for the translation of Pt-free radiosensitizer to the clinical practice, positively shifting the therapeutic vs. side effects equilibrium for the management of HNSCCs.

Synthesis and biological evaluation of novel 3,6- amide and thioamide substituted- 2,3,4,9-tetrahydro-1H-carbazoles for anti-cancer activity

Herein, we report the synthesis of new compounds with demonstrated anticancer properties based on the 2,3,4,9-tetrahydro-1H-carbazole scaffold. The Fischer indolization method was used to close the heterocyclic motif. The synthesis method's scope and limitations were thoroughly assessed through a series of experiments. Biological assays revealed that two thioamide compounds exhibited significant anticancer activity against MCF-7, HTC116, and A596 cell lines. Comprehensive in vitro profiling included evaluation of cell cytotoxicity, morphological alterations, colony formation and cell adhesion in 3D cultures, cell cycle analysis, DNA damage induction, impact on mitochondria, and apoptosis. Ex ovo studies further demonstrated these compounds' potential to inhibit angiogenic processes. Our results indicate that the newly developed compounds activate processes leading to DNA damage and disruption of mitochondrial function.

The Chick Embryo Chorioallantoic Membrane (CAM) Assay: A Novel Experimental Model in Dental Research

Animal experimental models are ruled out by respecting the 3Rs (Replacement, Reduction, Refinement) rules which governed the experimental research for decades with an increased tendency to minimize as much as it is possible any pain suffering or distress that the animals might feel. The chick embryo chorioallantoic membrane (CAM) model is an alternative to other experimental models due to its superior properties compared to other animal models. The CAM is painless by itself due to the lack of innervation and has no immune cells till the 11th day of incubation. Thus, it is extensively used for implanting malignant tumors and assessing them in relation to their metastatic and angiogenic potential. Also, various biomaterials from collagen to hard scaffolds can be implanted on the CAM surface and analyzed mainly related to their property of inducing inflammation. Dental research often uses mouse or rabbit models for experimental purposes. Different surgical techniques from experimentally induced periodontal disease to experimental dental implants may cause pain and suffering to animals. Due to all these arguments, the CAM model is a quick, cheap, and reliable alternative to other animal experimental models used in dental research. Despite its usefulness as an experimental model for different applications, ranging from inflammation studies to cancer research, the CAM model is insufficiently used in dental research. Currently, about 135 studies pertaining to this issue are available in PubMed, the majority of which focus on the reactivity of CAM vessels to various materials employed in dentistry. Limited data exist about the capacity of the CAM to promote osteogenic differentiation of dental stem cells or to enhance biomaterial integration into novel tissue architectures. The present review critically analyzed the use of the CAM model as an experimental tool in dental research. We selected from PubMed all the papers having as topic the CAM in dentistry by searching based on the following keywords: " chorioallantoic membrane, dentistry" or "chorioallantoic membrane, dental ". We focused on discussing the benefits and limitations of the CAM model in dental studies and its prospective role as a preclinical instrument for the assessment of dental tissues, biomaterials, or different dentistry-related substances prior to their use for various purposes in dental clinical practice. ​​​​​​The impact of the CAM model-derived preclinical findings on clinical practice will be also stated by mentioning "pros and cons" arguments. The last part of the present paper reviewed the perspective of CAM assay used in combination with other experimental techniques such as tooth organoids and also the strengths and weaknesses of other species CAM assays recently developed in ostrich and Nile crocodile CAMs.

An in vivo tumour organoid model based on the chick embryonic chorioallantoic membrane mimics key characteristics of the patient tissue: a proof-of-concept study

BACKGROUND

Patient-derived tumour organoids (PDOs) are highly advanced in vitro models for disease modelling, yet they lack vascularisation. To overcome this shortcoming, organoids can be inoculated onto the chorioallantoic membrane (CAM); the highly vascularised, not innervated extraembryonic membrane of fertilised chicken eggs. Therefore, we aimed to (1) establish a CAM patient-derived xenograft (PDX) model based on PDOs generated from the liver metastasis of a colorectal cancer (CRC) patient and (2) to evaluate the translational pipeline (patient - in vitro PDOs - in vivo CAM-PDX) regarding morphology, histopathology, expression of C-X-C chemokine receptor type 4 (CXCR4), and radiotracer uptake patterns.

RESULTS

The main liver metastasis of the CRC patient exhibited high 2-[18F]FDG uptake and moderate and focal [68Ga]Ga-Pentixafor accumulation in the peripheral part of the metastasis. Inoculation of PDOs derived from this region onto the CAM resulted in large, highly viable, and extensively vascularised xenografts, as demonstrated immunohistochemically and confirmed by high 2-[18F]FDG uptake. The xenografts showed striking histomorphological similarity to the patient's liver metastasis. The moderate expression of CXCR4 was maintained in ovo and was concordant with the expression levels of the patient's sample and in vitro PDOs. Following in vitro re-culturing of CAM-PDXs, growth, and [68Ga]Ga-Pentixafor uptake were unaltered compared to PDOs before transplantation onto the CAM. Although [68Ga]Ga-Pentixafor was taken up into CAM-PDXs, the uptake in the baseline and blocking group were comparable and there was only a trend towards blocking.

CONCLUSIONS

We successfully established an in vivo CAM-PDX model based on CRC PDOs. The histomorphological features and target protein expression of the original patient's tissue were mirrored in the in vitro PDOs, and particularly in the in vivo CAM-PDXs. The [68Ga]Ga-Pentixafor uptake patterns were comparable between in vitro, in ovo and clinical data and 2-[18F]FDG was avidly taken up in the patient's liver metastasis and CAM-PDXs. We thus propose the CAM-PDX model as an alternative in vivo model with promising translational value for CRC patients.

Liver cancer in ovo models for preclinical testing

Immunotherapies have significantly improved the prognosis of patients with advanced hepatocellular carcinoma (HCC), although more than 70% of patients still do not respond to this first-line treatment. Many new combination strategies are currently being explored, which drastically increases the need for preclinical models that would allow large-scale testing of new immunotherapies and their combinations. We developed several in ovo (in the egg) human liver cancer models, based on human tumor xenografts of different liver cancer cell lines on the chicken embryo's chorioallantoic membrane. We characterized the angiogenesis, as well as the collagen accumulation and tumor immune microenvironment, and tested atezolizumab (anti-PD-L1) plus bevacizumab (anti-VEGF) treatment. Our results show the involvement of chicken immune cells in tumor growth, reproducing a classical non-inflamed "cold" as well as inflamed "hot" tumor status, depending on the in ovo liver cancer model. The treatment by atezolizumab and bevacizumab was highly efficient in the "hot" tumor model PLC/PRF/5 in ovo with the reduction of tumor size by 76% (p ≤ .0001) compared with the control, whereas the efficacy was limited in the "cold" Hep3B in ovo tumor. The contribution of the anti-PD-L1 blockade to the anti-tumoral effect in the PLC/PRF/5 in ovo model was demonstrated by the efficacy of atezolizumab monotherapy (p = .0080, compared with the control). To conclude, our study provides a detailed characterization and rational arguments that could help to partially replace conventional laboratory animals with a more ethical model, suited to the current needs of preclinical research of new immunotherapies for liver cancer.

Preclinical Models of Hepatocellular Carcinoma: Current Utility, Limitations, and Challenges

Hepatocellular carcinoma (HCC), the predominant primary liver tumor, remains one of the most lethal cancers worldwide, despite the advances in therapy in recent years. In addition to the traditional chemically and dietary-induced HCC models, a broad spectrum of novel preclinical tools have been generated following the advent of transgenic, transposon, organoid, and in silico technologies to overcome this gloomy scenario. These models have become rapidly robust preclinical instruments to unravel the molecular pathogenesis of liver cancer and establish new therapeutic approaches against this deadly disease. The present review article aims to summarize and discuss the commonly used preclinical models for HCC, evaluating their strengths and weaknesses.

Pharmacological Characterization of SDX-7320/Evexomostat: A Novel Methionine Aminopeptidase Type 2 Inhibitor with Anti-tumor and Anti-metastatic Activity

Methionine aminopeptidase type 2 (METAP2) is a ubiquitous, evolutionarily conserved metalloprotease fundamental to protein biosynthesis which catalyzes removal of the N-terminal methionine residue from nascent polypeptides. METAP2 is an attractive target for cancer therapeutics based upon its over-expression in multiple human cancers, the importance of METAP2-specific substrates whose biological activity may be altered following METAP2 inhibition, and additionally, that METAP2 was identified as the target for the anti-angiogenic natural product, fumagillin. Irreversible inhibition of METAP2 using fumagillin analogues has established the anti-angiogenic and anti-tumor characteristics of these derivatives; however, their full clinical potential has not been realized due to a combination of poor drug-like properties and dose-limiting central nervous system (CNS) toxicity. This report describes the physicochemical and pharmacological characterization of SDX-7320 (evexomostat), a polymer-drug conjugate of the novel METAP2 inhibitor (METAP2i) SDX-7539. In vitro binding, enzyme, and cell-based assays demonstrated that SDX-7539 is a potent and selective METAP2 inhibitor. In utilizing a high molecular weight, water-soluble polymer to conjugate the novel fumagillol-derived, cathepsin-released, METAP2i SDX-7539, limitations observed with prior generation, small molecule fumagillol derivatives were ameliorated including reduced CNS exposure of the METAP2i, and prolonged half-life enabling convenient administration. Multiple xenograft and syngeneic cancer models were utilized to demonstrate the anti-tumor and anti-metastatic profile of SDX-7320. Unlike polymer-drug conjugates in general, reductions in small molecule-equivalent efficacious doses following polymer conjugation were observed. SDX-7320 has completed a phase I clinical safety study in patients with late-stage cancer and is currently being evaluated in multiple phase Ib/II clinical studies in patients with advanced solid tumors.

Continuous iontronic chemotherapy reduces brain tumor growth in embryonic avian in vivo models

Local and long-lasting administration of potent chemotherapeutics is a promising therapeutic intervention to increase the efficiency of chemotherapy of hard-to-treat tumors such as the most lethal brain tumors, glioblastomas (GBM). However, despite high toxicity for GBM cells, potent chemotherapeutics such as gemcitabine (Gem) cannot be widely implemented as they do not efficiently cross the blood brain barrier (BBB). As an alternative method for continuous administration of Gem, we here operate freestanding iontronic pumps - "GemIPs" - equipped with a custom-synthesized ion exchange membrane (IEM) to treat a GBM tumor in an avian embryonic in vivo system. We compare GemIP treatment effects with a topical metronomic treatment and observe that a remarkable growth inhibition was only achieved with steady dosing via GemIPs. Daily topical drug administration (at the maximum dosage that was not lethal for the embryonic host organism) did not decrease tumor sizes, while both treatment regimes caused S-phase cell cycle arrest and apoptosis. We hypothesize that the pharmacodynamic effects generate different intratumoral drug concentration profiles for each technique, which causes this difference in outcome. We created a digital model of the experiment, which proposes a fast decay in the local drug concentration for the topical daily treatment, but a long-lasting high local concentration of Gem close to the tumor area with GemIPs. Continuous chemotherapy with iontronic devices opens new possibilities in cancer treatment: the long-lasting and highly local dosing of clinically available, potent chemotherapeutics to greatly enhance treatment efficiency without systemic side-effects. SIGNIFICANCE STATEMENT: Iontronic pumps (GemIPs) provide continuous and localized administration of the chemotherapeutic gemcitabine (Gem) for treating glioblastoma in vivo. By generating high and constant drug concentrations near the vascularized growing tumor, GemIPs offer an efficient and less harmful alternative to systemic administration. Continuous GemIP dosing resulted in remarkable growth inhibition, superior to daily topical Gem application at higher doses. Our digital modelling shows the advantages of iontronic chemotherapy in overcoming limitations of burst release and transient concentration profiles, and providing precise control over dosing profiles and local distribution. This technology holds promise for future implants, could revolutionize treatment strategies, and offers a new platform for studying the influence of timing and dosing dependencies of already-established drugs in the fight against hard-to-treat tumors.

In vitro and in ovo photodynamic efficacy of nebulized curcumin-loaded tetraether lipid liposomes prepared by DC as stable drug delivery system

Lung cancer is one of the most common causes of high mortality worldwide. Current treatment strategies, e.g., surgery, radiotherapy, chemotherapy, and immunotherapy, insufficiently affect the overall outcome. In this study, we used curcumin as a natural photosensitizer in photodynamic therapy and encapsulated it in liposomes consisting of stabilizing tetraether lipids aiming for a pulmonary drug delivery system against lung cancer. The liposomes with either hydrolyzed glycerol-dialkyl-glycerol tetraether (hGDGT) in different ratios or hydrolyzed glycerol-dialkyl-nonitol tetraether (hGDNT) were prepared by dual centrifugation (DC), an innovative method for liposome preparation. The liposomes' physicochemical characteristics before and after nebulization and other nebulization characteristics confirmed their suitability. Morphological characterization using atomic force and transmission electron microscopy showed proper vesicular structures indicative of liposomes. Qualitative and quantitative uptake of the curcumin-loaded liposomes in lung adenocarcinoma (A549) cells was visualized and proven. Phototoxic effects of the liposomes were detected on A549 cells, showing decreased cell viability. The generation of reactive oxygen species required for PDT and disruption of mitochondrial membrane potential were confirmed. Moreover, the chorioallantoic membrane (CAM) model was used to further evaluate biocompatibility and photodynamic efficacy in a 3D cell culture context. Photodynamic efficacy was assessed by PET/CT after nebulization of the liposomes onto the xenografted tumors on the CAM with subsequent irradiation. The physicochemical properties and the efficacy of tetraether lipid liposomes encapsulating curcumin, especially liposomes containing hGDNT, in 2D and 3D cell cultures seem promising for future PDT usage against lung cancer.

Evaluating the photodynamic efficacy of nebulized curcumin-loaded liposomes prepared by thin-film hydration and dual centrifugation: In vitro and in ovo studies

Lung cancer, one of the most common causes of high mortality worldwide, still lacks appropriate and convenient treatment options. Photodynamic therapy (PDT) has shown promising results against cancer, especially in recent years. However, pulmonary drug delivery of the predominantly hydrophobic photosensitizers still represents a significant obstacle. Nebulizing DPPC/Cholesterol liposomes loaded with the photosensitizer curcumin via a vibrating mesh nebulizer might overcome current restrictions. In this study, the liposomes were prepared by conventional thin-film hydration and two other methods based on dual centrifugation. The liposomes' physicochemical properties were determined before and after nebulization, showing that liposomes do not undergo any changes. However, morphological characterization of the differently prepared liposomes revealed structural differences between the methods in terms of lamellarity. Internalization of curcumin in lung adenocarcinoma (A549) cells was visualized and quantified. The generation of reactive oxygen species because of the photoreaction was also proven. The photodynamic efficacy of the liposomal formulations was tested against A549 cells. They revealed different phototoxic responses at different radiant exposures. Furthermore, the photodynamic efficacy was investigated after nebulizing curcumin-loaded liposomes onto xenografted tumors on the CAM, followed by irradiation, and evaluated using positron emission tomography/computed tomography and histological analysis. A decrease in tumor metabolism could be observed. Based on the efficacy of curcumin-loaded liposomes in 2D and 3D models, liposomes, especially with prior film formation, can be considered a promising approach for PDT against lung cancer.

The chicken chorioallantoic membrane assay revisited - A face-lifted approach for new perspectives in placenta research

The study of very early human placentation is largely limited due to ethical restrictions on the use of embryonic tissue and the fact that the placental anatomy of common laboratory animal models varies considerably from that of humans. In recent years several promising models, including trophoblast stem cell-derived organoids, have been developed that have also proven useful for the study of important trophoblast differentiation processes. However, the consideration of maternal blood flow in trophoblast invasion models currently appears to be limited to animal models. An almost forgotten model to study the invasive behavior of trophoblasts is to culture them in vitro on the chicken chorioallantoic membrane (CAM), showing an extraembryonic vascular network in its mesenchymal stroma that is continuously perfused by the chicken embryonic blood circulation. Here, we present an extension of the previously described ex ovo CAM assay and describe the use of cavity-bearing trophoblast spheroids obtained from the first trimester cell line ACH-3P. We demonstrate how spheroids penetrated the CAM and that erosion of CAM vessels by trophoblasts led to filling of the spheroid cavities with chicken blood, mimicking initial steps of intervillous space blood perfusion. Moreover, we prove that this model is useful for state-of-the-art techniques including immunofluorescence and in situ padlock probe hybridization, making it a versatile tool to study aspects of trophoblast invasion in presence of blood flow.

Prostaglandin 15d-PGJ2 inhibits proliferation of lung adenocarcinoma cells by inducing ROS production and activation of apoptosis via sirtuin-1

Lung adenocarcinoma (LUADC) belongs to the most prevalent and lethal cancer types. As 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) displays anti-oxidative, -inflammatory, and -cancer properties, we investigated whether this cyclopentenone PG, a stable degradation end-product of cyclooxygenase-generated PGD2, exerts beneficial effects in three LUADC cell lines (A549, H1299, H23). We here report that 15d-PGJ2 had substantial cytotoxic effects in all three LUADC cell lines by promoting early apoptosis and inhibiting the cell cycle, proliferation, and migration. As indicators of cell malignancy, scratch closure and colony formation were significantly inhibited by 15d-PGJ2. 15d-PGJ2 induced generation of ROS and subsequent activation of MAPKs. Expression of Nrf-2, a well-known tumor driver, was markedly diminished by 15d-PGJ2 treatment. Although PPARγ, DP1, and DP2 are expressed in LUADC cells, blocking these receptors with specific inhibitors (SR16832 and BW245C) did not reverse 15d-PGJ2-mediated cytotoxicity, suggesting receptor-independent effects. 15d-PGJ2 decreased SIRT1 expression in LUADC cells and the knockdown of SIRT1 diminished the cytotoxic effects of 15d-PGJ2. Importantly, 15d-PGJ2 significantly reduced tumor growth using the chorioallantoic membrane (CAM) assay. The structural analog of 15d- PGJ2, 9,10-dihydro-15d-PGJ2 (lacking the α,β-unsaturated ketone structural element), did not show any toxic effects in LUADC cells. Altogether, our findings suggest that 15d-PGJ2 led to significantly reduced tumor growth and cell proliferation in three LUADC cell lines. The CAM assay results suggest that 15d-PGJ2 is a suitable endogenous compound to interfere with LUADC tumor progression. We show that SIRT1 modulates the effects of 15d-PGJ2 and may be used as a therapeutic target for LUADC.

Testing the effects of photobiomodulation on angiogenesis in a newly established CAM burn wound model

Burn wounds are a common challenge for medical professionals. Current burn wound models hold several limitations, including a lack of comparability due to the heterogeneity of wounds and differences in individual wound healing. Hence, there is a need for reproducible in vivo models. In this study, we established a new burn wound model using the chorioallantoic membrane assay (CAM) as a surrogate model for animal experiments. The new experimental setup was tested by investigating the effects of the auspicious biophysical therapy, photobiomodulation (PBM), on the wound healing of an induced CAM burn wound with a metal stamp. PBM has been shown to positively influence wound healing through vascular proliferative effects and the increased secretion of chemotactic substances. The easily accessible burn wounds can be treated with various therapies. The model enables the analysis of ingrowing blood vessels (angiogenesis) and diameter and area of the wounds. The established model was used to test the effects of PBM on burn wound healing. PBM promoted angiogenesis in burn wounds on day 4 (p = 0.005). Furthermore, there was a not significant trend toward a higher number of vessels for day 6 (p = 0.065) in the irradiated group. Changes in diameter (p = 0.129) and the burn area (p = 0.131) were not significant. Our results suggest that CAM can be a suitable model for studying burn wounds. The novel experimental design enables reproducible and comparable studies on burn wound treatment.

Facilitated Transport across Glycocalyceal Barriers in the Chick Chorioallantoic Membrane

Targeted drug delivery to visceral organs offers the possibility of not only limiting the required dose, but also minimizing drug toxicity; however, there is no reliable method for delivering drugs to the surface of visceral organs. Here, we used six color tracers and the chick chorioallantoic membrane (CAM) model to investigate the use of the heteropolysaccharide pectin to facilitate tracer diffusion across the glycocalyceal charge barrier. The color tracers included brilliant blue, Congo red, crystal violet, indocyanine green, methylene blue, and methyl green. The direct application of the tracers to the CAM surface or embedding tracers into linear-chain nanocellulose fiber films resulted in no significant diffusion into the CAM. In contrast, when the tracers were actively loaded into branched-chain pectin films, there was significant detectable diffusion of the tracers into the CAM. The facilitated diffusion was observed in the three cationic tracers but was limited in the three anionic tracers. Diffusion appeared to be dependent on ionic charge, but independent of tracer size or molecular mass. We conclude that dye-loaded pectin films facilitated the diffusion of color tracers across the glycocalyceal charge barrier and may provide a therapeutic path for drug delivery to the surface of visceral organs.

Dataset of chicken-embryo blood cells exposed to quercetin, methyl methanesulfonate, or cadmium chloride

Toxicological analysis of the effects of natural compounds is frequently mandated to assess their safety. In addition to more simple in vitro cellular systems, more complex biological systems can be used to evaluate toxicity. This dataset is comprised of bright-field microscopy images of chicken-embryo blood cells, a complex biological model that recapitulates several features found in human organisms, including circulation in blood stream and biodistribution to different organs. In the presented collection of blood smear images, cells were exposed to the flavonoid quercetin, and the two mutagens methyl methanesulfonate (MMS) and cadmium chloride (CdCl2). In ovo models offer a unique opportunity to investigate the effects of various substances, pathogens, or cancer treatments on developing embryos, providing valuable insights into potential risks and therapeutic strategies. In toxicology, in ovo models allow for early detection of harmful compounds and their impact on embryonic development, aiding in the assessment of environmental hazards. In immunology, these models offer a controlled system to explore the developing immune responses and the interaction between pathogens and host defenses. Additionally, in ovo models are instrumental in oncology research as they enable the study of tumor development and response to therapies in a dynamic, rapidly developing environment. Thus, these versatile models play a crucial role in advancing our understanding of complex biological processes and guiding the development of safer therapeutics and interventions. The data presented here can aid in understanding the potential toxic effects of these substances on hematopoiesis and the overall health of the developing organism. Moreover, the large dataset of blood smear images can serve as a resource for training machine learning algorithms to automatically detect and classify blood cells, provided that specific optimized conditions such as image magnification and background light are maintained for comparison. This can lead to the development of automated tools for blood cell analysis, which can be useful in research. Moreover, the data is amenable to the use as teaching and learning resource for histology and developmental biology.

CAM Model: Intriguing Natural Bioreactor for Sustainable Research and Reliable/Versatile Testing

We are witnessing the revival of the CAM model, which has already used been in the past by several researchers studying angiogenesis and anti-cancer drugs and now offers a refined model to fill, in the translational meaning, the gap between in vitro and in vivo studies. It can be used for a wide range of purposes, from testing cytotoxicity, pharmacokinetics, tumorigenesis, and invasion to the action mechanisms of molecules and validation of new materials from tissue engineering research. The CAM model is easy to use, with a fast outcome, and makes experimental research more sustainable since it allows us to replace, reduce, and refine pre-clinical experimentation ("3Rs" rules). This review aims to highlight some unique potential that the CAM-assay presents; in particular, the authors intend to use the CAM model in the future to verify, in a microenvironment comparable to in vivo conditions, albeit simplified, the angiogenic ability of functionalized 3D constructs to be used in regenerative medicine strategies in the recovery of skeletal injuries of critical size (CSD) that do not repair spontaneously. For this purpose, organotypic cultures will be planned on several CAMs set up in temporal sequences, and a sort of organ model for assessing CSD will be utilized in the CAM bioreactor rather than in vivo.

Circulating tumor cell-derived preclinical models: current status and future perspectives

Despite the advancements made in the diagnosis and treatment of cancer, the stages associated with metastasis remain largely incurable and represent the primary cause of cancer-related deaths. The dissemination of cancer is facilitated by circulating tumor cells (CTCs), which originate from the primary tumor or metastatic sites and enter the bloodstream, subsequently spreading to distant parts of the body. CTCs have garnered significant attention in research due to their accessibility in peripheral blood, despite their low abundance. They are being extensively studied to gain a deeper understanding of the mechanisms underlying cancer dissemination and to identify effective therapeutic strategies for advanced stages of the disease. Therefore, substantial efforts have been directed towards establishing and characterizing relevant experimental models derived from CTCs, aiming to provide relevant tools for research. In this review, we provide an overview of recent progress in the establishment of preclinical CTC-derived models, such as CTC-derived xenografts (CDX) and cell cultures, which show promise for the study of CTCs. We discuss the advantages and limitations of these models and conclude by summarizing the potential future use of CTCs and CTC-derived models in cancer treatment decisions and their utility as precision medicine tools.

Danthron, an Anthraquinone Isolated from a Marine Fungus, Is a New Inhibitor of Angiogenesis Exhibiting Interesting Antitumor and Antioxidant Properties

The role played by a sustained angiogenesis in cancer and other diseases stimulates the interest in the search for new antiangiogenic drugs. In this manuscript, we provide evidence that 1,8- dihydroxy-9,10-anthraquinone (danthron), isolated from the fermentation broth of the marine fungus Chromolaenicola sp. (HL-114-33-R04), is a new inhibitor of angiogenesis. The results obtained with the in vivo CAM assay indicate that danthron is a potent antiangiogenic compound. In vitro studies with human umbilical endothelial cells (HUVEC) reveal that this anthraquinone inhibits certain key functions of activated endothelial cells, including proliferation, proteolytic and invasive capabilities and tube formation. In vitro studies with human breast carcinoma MDA-MB231 and fibrosarcoma HT1080 cell lines suggest a moderate antitumor and antimetastatic activity of this compound. Antioxidant properties of danthron are evidenced by the observation that it reduces the intracellular reactive oxygen species production and increases the amount of intracellular sulfhydryl groups in endothelial and tumor cells. These results support a putative role of danthron as a new antiangiogenic drug with potential application in the treatment and angioprevention of cancer and other angiogenesis-dependent diseases.

A Novel Breast Cancer Xenograft Model Using the Ostrich Chorioallantoic Membrane-A Proof of Concept

The avian chorioallantoic membrane (CAM) assay has attracted scientific attention in cancer research as an alternative or complementary method for in vivo animal models. Here, we present a xenograft model based on the ostrich (struthio camelus) CAM assay for the first time. The engraftment of 2 × 10⁶ breast cancer carcinoma MDA-MB-231 cells successfully lead to tumor formation. Tumor growth monitoring was evaluated in eight fertilized eggs after xenotransplantation. Cancer cells were injected directly onto the CAM surface, close to a well-vascularized area. Histological analysis confirmed the epithelial origin of tumors. The CAM of ostrich embryos provides a large experimental surface for the xenograft, while the comparably long developmental period allows for a long experimental window for tumor growth and treatment. These advantages could make the ostrich CAM assay an attractive alternative to the well-established chick embryo model. Additionally, the large size of ostrich embryos compared to mice and rats could help overcome the limitations of small animal models. The suggested ostrich model is promising for future applications, for example, in radiopharmaceutical research, the size of the embryonal organs may compensate for the loss in image resolution caused by physical limitations in small animal positron emission tomography (PET) imaging.

The Chorioallantoic Membrane Xenograft Assay as a Reliable Model for Investigating the Biology of Breast Cancer

The chorioallantoic membrane (CAM) assay is an alternative in vivo model that allows for minimally invasive research of cancer biology. Using the CAM assay, we investigated phenotypical and functional characteristics (tumor grade, mitosis rate, tumor budding, hormone receptor (HR) and HER2 status, Ki-67 proliferation index) of two breast cancer cell lines, MCF-7 and MDA-MB-231, which resemble the HR+ (luminal) and triple-negative breast cancer (TNBC) subgroups, respectively. Moreover, the CAM results were directly compared with murine MCF-7- and MDA-MB-231-derived xenografts and human patient TNBC tissue. Known phenotypical and biological features of the aggressive triple-negative breast cancer cell line (MDA-MB-231) were confirmed in the CAM assay, and mouse xenografts. Furthermore, the histomorphological and immunohistochemical variables assessed in the CAM model were similar to those in human patient tumor tissue. Given the confirmation of the classical biological and growth properties of breast cancer cell lines in the CAM model, we suggest this in vivo model to be a reliable alternative test system for breast cancer research to reduce murine animal experiments.