Search Results (382)

In vitro culture systems have advanced cancer biology, particularly through 2D and 3D tumor cultures. These have answered numerous scientific inquiries and propelled human oncologic research, with growing recognition of their potential to improve cancer treatment in companion animals, specifically cats and dogs. These species develop cancer spontaneously, closely resembling specific human cancer subtypes. For example, canine and feline mammary tumors are especially valuable for studying tumor biology. In vitro models from these tumors therefore offer a unique opportunity for veterinary cancer research. Recent 3D cell culture advancements provide promising platforms for predicting therapeutic responses in human cancer and may be applied to mammary tumors in animals. However, while limitations in fully recapitulating in vivo conditions and predicting chemotherapy response have been observed in colorectal tumoroids, similar challenges are emerging in mammary and breast tumors. In particular, canine mammary tumors and human breast cancers share critical heterogeneity and microenvironmental factors usually inadequately modeled in vitro. This review critically examines the predictivity of 3D mammary tumoroids from humans and companion animals, highlighting challenges related to stromal and immune cell preservation, reproducibility, and the translational gap between in vitro findings and clinical outcomes. We propose future directions to optimize these models for both comparative oncology and veterinary-specific applications. Full article

The renin–angiotensin–aldosterone system (RAAS) plays a pivotal role in regulating cardiovascular function, fluid balance, and blood pressure. Recent research has revealed the RAAS’s influence extends beyond cardiovascular physiology, encompassing key roles in inflammation, fibrosis, immune regulation, cancer progression, and organ-specific disease mechanisms. This review provides a comprehensive overview of classical and alternative RAAS pathways, focusing on the dual roles of angiotensin II (Ang II) and angiotensin-(1–7) (Ang 1–7), mediated through AT1R, AT2R, MasR, and MrgD receptors. We discuss molecular signaling cascades, including mitochondrial, nuclear, and caveolae-mediated mechanisms, and explore the impact of RAAS modulation on hepatic fibrosis, vascular remodeling, and autoimmune inflammation. Genetic models and emerging pharmacologic strategies illustrate tissue-specific RAAS actions, emphasizing the therapeutic potential of enhancing the ACE2/Ang 1–7/Mas axis while inhibiting the deleterious ACE/Ang II/AT1R signaling. Furthermore, we highlight implications for veterinary medicine, particularly in canine chronic inflammatory enteropathies, where RAAS dysfunction may contribute to treatment resistance. Understanding RAAS complexity and inter-receptor crosstalk is essential for developing new therapeutic strategies targeting cardiovascular, hepatic, and inflammatory diseases in both human and veterinary contexts. Full article

Nuclear receptors are involved in multiple biological processes, among which RORγ can regulate the expression of inflammation-related genes and is thus frequently used as a therapeutic target for cancer. Canine mammary cancer is one of the most common tumor diseases in dogs, with a relative incidence rate of 46.71% for CMT in China over the past five years, severely threatening the life and health of dogs. Therefore, the search for novel drugs targeting canine mammary cancer is of great significance. This study aims to investigate how the RORγ inhibitors W6134 and XY018 affect the expression of inflammatory genes through histone modifications in CMT-N7 cells. These results show that W6134 and XY018 can upregulate signaling pathways related to inflammation and apoptosis and influence the expression of associated genes. The close link between RORγ and inflammation-related genes further confirms that RORγ may serve as a therapeutic target for canine cancer. Additionally, ChIP-qPCR was used to detect the enrichment of histone markers such as P300, H3K27ac, H3K4me1, H3K9la, and H3K9bhb at the target loci of CXCL10 and MECOM genes. Collectively, our findings provide molecular evidence for the protective role of RORγ in canine mammary cancer, potentially by regulating inflammatory pathways via histone modifications, offering new insights for improving the cure rate and survival of affected dogs. Full article

Mast cell tumours (MCT) are the most common cutaneous neoplasms in dogs, with variable behaviours and patient survival time. Both indolent and aggressive forms have been described, but much remains to be explored regarding prognosis and therapy. Evidence has highlighted the influence of microbiota on multiple health and disease processes, including certain types of cancer in humans. However, knowledge remains scarce regarding microbiota biology and its interactions in both humans and canine cancer patients. This study aimed to characterise the faecal microbiota of dogs with MCT and compare it with that of healthy individuals. Twenty-eight dogs diagnosed with MCT and twenty-eight healthy dogs were enrolled in the study. Faecal samples were collected and analysed by Illumina sequencing of 16S rRNA genes. Alpha diversity was significantly lower in dogs with cancer, and the species diversity InvSimpson Indexwas reduced (p = 0.019). Principal coordinate analysis showed significant differences in the bacterial profile of the two groups: there was a significant lower abundance of the genera Alloprevotella, Holdemanella, Erysipelotrichaceae_UCG-003, and Anaerobiospirillum and, conversely, a significant increase in the genera Escherichia-Shigella and Clostridium sensu stricto 1 in diseased dogs. At the phylum level, Bacteroidota was significantly reduced in diseased dogs (25% in controls vs. 19% in MCT dogs). In conclusion, sequencing analysis provided an overview of the bacterial profile and showed statistical differences in the microbial communities of dogs with MCT compared with healthy dogs, suggesting a link between the gut microbiota and MCT in this species. Full article

Background/Objectives: Mammary carcinoma is a common disease in female dogs. Cannabidiol (CBD) can inhibit cell proliferation and induce apoptosis in human cancer cells. However, its low solubility in aqueous media requires solvents such as ethanol or dimethylsulfoxide that limit their dosage. Incorporating CBD into oil-in-water nanoemulsions (Nem) can improve its aqueous dispersibility. This study aimed to develop a CBD-Nem formulation and evaluate its effects on canine mammary cancer cell lines (CF41.Mg and IPC366) and non-cancer cells (MDCK). Methods: CBD-Nem was prepared with Miglyol 812 oil and Epikuron 145 V as the surfactant, and was characterized by analyzing size, morphology, zeta potential, release profile, and uptake/internalization. Moreover, the antitumor effects of CBD-Nem were evaluated in cancer cells through viability, proliferation, cell cycle, and migration–invasion assays. Results: CBD-Nem exhibited a monodisperse nanometric population (~150 nm), spherical shape, and negative zeta potential (~−50 mV). The in vitro release kinetics showed slow and sustained delivery at both pH 5.5 and pH 7.4. Rhodamine-Nem, as a fluorescent model of CBD-Nem, was taken up and homogenously internalized in CF41.Mg cells. CBD-Nem decreased the viability of cancer cells with a maximum effect at 50 µM and showed a lower toxicity in MDCK cells. Long-term efficacy (20 days) was evidenced by CBD-Nem at inhibiting colony formation in cancer cells. Furthermore, CBD-Nem reduced the proportion of cells in the G2-M phase, induced apoptosis, and inhibited the migration and invasion of CF41.Mg cells. Conclusions: CBD-Nem exhibited an in vitro antitumor effect, which supports its study in dogs with mammary carcinoma. Full article

The tumor microenvironment (TME) plays a central role in cancer progression, with tumor-associated macrophages (TAMs) and extracellular matrix (ECM) components such as collagen being key modulators of invasiveness and immune regulation. Although macrophage infiltration and ECM remodeling are well-documented individually, their coordinated contribution to mammary carcinoma aggressiveness remains underexplored, particularly in comparative oncology models. This study analyzed 117 mammary carcinoma samples—59 from dogs and 58 from women—using immunohistochemistry, immunofluorescence, and second-harmonic-generation (SHG) microscopy. We quantified TAM density and phenotype (CD206, iNOS, and S100A8/A9), assessed collagen fiber organization, and examined correlations with clinical–pathological variables and overall survival. Increased TAM infiltration was associated with a higher histological grade, aggressive molecular subtypes, enhanced cell proliferation, and shortened survival in dogs. High TAM density also correlated with decreased collagen fiber length and increased alignment, suggesting active immune–matrix remodeling in aggressive tumors. Macrophage phenotyping revealed heterogeneous populations, with CD206⁺ cells predominating in high-grade tumors, while S100A8/A9⁺/iNOS⁺ phenotypes were enriched in less aggressive subtypes. The findings were consistent across species, reinforcing the relevance of canine models. Our results identify macrophage–collagen interactions as critical determinants of tumor aggressiveness in mammary carcinomas. This study bridges comparative oncology and translational research by proposing immune–ECM signatures as potential prognostic biomarkers and therapeutic targets. These insights contribute to the advancement of molecular oncology in Brazil by supporting innovative strategies that integrate immune modulation and matrix-targeted interventions in breast cancer. Full article

Canine histiocytic sarcoma (HS) is a rare tumor with a poor prognosis. Rapid tumor growth often causes central hypoxia and starvation, impacting tumor progression. In the present study, HS cells were cultured under hypoxia and starvation for 1 and 3 days, simulating intermediate and central tumor zones, respectively. Cells were counted at each time point, followed by RNAseq analysis. Only hypoxia significantly reduced the cell number (p < 0.05). Short-term hypoxia altered 1645 differentially expressed genes (DEGs). Upregulated genes belonged to vasculature development, and downregulated genes to cell cycle processes. Short-term starvation affected 157 genes, mainly involving responses to stimuli. Prolonged hypoxia and starvation induced 1301 and 836 DEGs, respectively. Prolonged hypoxia upregulated genes mainly involved in immune responses, response to stimulus, adhesion, and angiogenesis. Prolonged starvation upregulated genes associated with signaling, adhesion, circulatory system development, and response to stimulus. Lipid metabolism and cell cycle pathways were downregulated under prolonged hypoxia and starvation, respectively. KEGG “pathways in cancer” were enriched under all conditions (adjusted p-values < 0.05). These findings indicate that hypoxia and starvation significantly alter the expression of genes involved in tumor progression. Further studies, namely post-translational analyses, are needed to elucidate the functional impact of these changes and identify potential therapeutic targets. Full article

A single domain antibody (SDAb) targeting canine PD-1 was developed as a potential immunotherapeutic for canine cancer. An alpaca was immunized with canine PD-1 protein, and a phage-display library was constructed using mRNA isolated from peripheral lymphocytes. Screening of the library yielded multiple SDAb candidates capable of nanomolar binding to canine PD-1. Among these, clone STX-1b5 demonstrated high expression in a yeast-based recombinant system and was selected for further characterization. Binding and competition assays using ELISA confirmed its ability to bind canine PD-1 and block PDL-1 interaction. In silico structural modeling supported the interaction of STX-1b5 with key PD-1 residues implicated in ligand binding. These findings support the feasibility of using SDAbs and cost-effective yeast expression systems to generate immunotherapeutics for veterinary use, with STX-1b5 representing a promising lead candidate for future clinical development. Full article

Mammary tumors are the most common neoplasms diagnosed in female dogs and have been considered excellent models for studying human breast cancer. Establishing cell lines from primary cultures of canine mammary tumors provides an in vitro model to better understand the disease and develop new treatments. This study aimed to establish and characterize canine mammary tumor cell lines. Ten cell cultures were generated from tumor tissue obtained from affected dogs, including seven from primary mammary tumors and three from metastatic sites. Characterization included molecular marker expression (ER, PR, HER2, cytokeratin 5/6 (CK5/6), vimentin, and the marker of cell proliferation Ki67) and in vitro tumorigenic capacity assessment. Additionally, the susceptibility of five cell lines to DOX, 5-FU, paclitaxel, colchicine, and carboplatin was evaluated using the MTT assay. ICC analysis revealed negative expression of hormonal receptors (ER and PR) in five cell lines, while only one cell line was positive for both. Six cell lines were HER2-negative and positive for vimentin. Five cell lines exhibited in vitro tumorigenic capacity, forming colonies in soft agar. DOX showed the highest growth-inhibitory effect (DOX > Paclitaxel > Colchicine > 5-FU > Carboplatin). Two cell lines had a minimal concentration for 50% inhibition in vitro (IC₅₀) < 0.63 µM and 4.37 ± 0.40 µM for DOX, while one was sensitive to colchicine and paclitaxel (IC₅₀ 0.19 µM and 0.04 µM, respectively). All tested cell lines were resistant to carboplatin and 5-FU. These cell lines provide a valuable model for studying breast cancer in humans and dogs and evaluating new potential therapeutic strategies. Full article

Cutaneous neoplasia is among the most common illnesses in dogs and can pose significant risks. Accurate morphological diagnosis of these conditions is vital for effective treatment and management. In this retrospective study, a total of 3746 canine skin biopsies were submitted to a veterinary reference diagnostic laboratory and evaluated using histopathology. The variables assessed included age, sex, breed, lesion, location, and histopathological diagnosis. Non-neoplastic lesions accounted for 61% of all analyzed samples, while neoplastic tumors accounted for 39%. When looking at age, dogs ranging 3–6 years and 7–9 years had at least six times higher risk of developing malignant neoplasia compared to those aged 0–2 years. Among the malignant neoplasms, mast cell tumors, hemangiosarcoma, and squamous cell carcinoma were the most observed, representing 30%, 18%, and 12% of cases, respectively. The breeds most frequently affected by malignant neoplasms included Pit Bull Terriers, Boxers, and mixed breeds, all of which comprised the majority of mast cell tumor cases at 50.54%. These findings are novel in this field and may assist small animal veterinarians in making preliminary diagnoses, while also helping pet owners understand the importance of skin cancer and its early detection. Full article

High-Z nanoparticles (NPs) have the potential to revolutionize cancer radiotherapy by radiosensitising tumours. This is particularly important for radioresistant cancers such as glioblastoma. A newer NP candidate in this area is thulium oxide nanoparticles (TmNPs). However, prior to clinical assessment, ideal NP characteristics, including biocompatibility, biosafety, and preferential uptake in cancer, should be assessed. This in vitro study compares the effects of TmNP treatment, without radiation, on 9L gliosarcoma (9LGS), a well-established glioblastoma cell model, with exposure to Madin Darby Canine Kidney (MDCK) cells, a widely used non-cancerous cell model. The findings demonstrated selective uptake of TmNPs in 9LGS over MDCK following treatment. A biological assessment of toxicity confirmed minimal long-term effects on MDCK, whilst TmNPs were observed to induce some notable cell death in 9LGS. Excessive TmNP uptake in 9LGS over time was observed to induce cell vacuolisation, which resulted in cell death via necrosis. It was concluded that this was the explanation for the underlying mechanisms of TmNP toxicity in cancer cells. This study was therefore able to demonstrate not only that TmNPs are a biocompatible, cancer-selective candidate for radiosensitiser usage, but further provided a theory to explain its mechanisms of cancer cell toxicity. Full article

Ten dogs with oral malignant melanoma were evaluated and treated with surgery, of which four dogs were diagnosed with melanotic melanoma and six were diagnosed with amelanotic melanoma. Serum samples from oral malignant melanoma (OMM) were collected at baseline, the day of the surgery, and every 3–4 months, during which time a clinical examination and chest X-rays were performed. Concentrations of GM-CSF, IFN-γ, IL-2, IL-6, IL-7, IL-8, IL-10, IL-15, IL-18, IP-10, KC-like, MCP-1, and TNFα were quantified. Follow-up samples indicated that after the removal of malignant melanoma, the serum levels of GM-CSF, IFN-γ, MCP-1, IL-18, and IL-2 increased significantly. In contrast, when comparing samples from dogs with OMM to those of patients in remission, the concentrations of IL-7 and MCP-1 were significantly higher in the remission samples than in the OMM samples. Furthermore, when comparing the serum concentrations between the OMM-metastasis samples and those patients in remission, elevated levels of MCP-1 were associated with poorer overall survival due to the development of OMM metastasis. Finally, a comparison of cytokines in the melanotic OMM and amelanotic OMM samples revealed that the amelanotic OMM samples exhibited higher concentrations of IL-6, IL-10, and IL-15 compared to the melanotic OMM samples. Full article

The mammalian immune system, including key components such as toll-like receptors (TLRs), lymphocytes, and cytokines, plays a vital role in defending against diseases. In dogs, genetic polymorphisms and epigenetic regulation of immune-related genes contribute to breed-specific differences in susceptibility or resistance to infectious, autoimmune, and inflammatory diseases. Cytokines, essential for immune cell differentiation and activation, exhibit variable expression among breeds due to genetic factors like single-nucleotide polymorphisms (SNPs) and miRNA regulation. This variability influences immune responses not only to infections but also to chronic inflammatory conditions and cancer, providing insights for improved diagnosis, treatment, and breeding. Selective breeding has further shaped diverse immune phenotypes across breeds, especially through genetic variations in the major histocompatibility complex (MHC) region, which affect vulnerability to immune-mediated and immunodeficiency disorders. Recent studies emphasize the role of specific miRNAs in modulating immune responses during parasitic and viral infections, opening new avenues for precision veterinary medicine and immunotherapy. This review highlights the genetic and epigenetic regulation of immune genes in dogs and explores their potential applications in advancing veterinary diagnostics, therapeutics, and breeding strategies to enhance canine health. Full article

Background/Objectives: Colorectal cancer (CRC) remains a major global health burden, marked by complex tumor–microenvironment interactions, genetic heterogeneity, and varied treatment responses. Effective preclinical models are essential for dissecting CRC biology and guiding personalized therapeutic strategies. This review aims to critically evaluate current experimental CRC models, assessing their translational relevance, limitations, and potential for integration into precision oncology. Methods: A systematic literature search was conducted across PubMed, Scopus, and Web of Science, focusing on studies employing defined in vitro, in vivo, and emerging integrative CRC models. Studies were included based on experimental rigor and relevance to therapeutic or mechanistic investigation. Models were compared based on molecular fidelity, tumorigenic capacity, immune interactions, and predictive utility. Results: CRC models were classified into in vitro (2D cell lines, spheroids, patient-derived organoids), in vivo (murine, zebrafish, porcine, canine), and integrative platforms (tumor-on-chip systems, humanized mice, AI-augmented simulations). Traditional models offer accessibility and mechanistic insight, while advanced systems better mimic human tumor complexity, immune landscapes, and treatment response. Tumor-on-chip and AI-driven models show promise in simulating dynamic tumor behavior and predicting clinical outcomes. Cross-platform integration enhances translational validity and enables iterative model refinement. Conclusions: Strategic deployment of complementary CRC models is critical for advancing translational research. This review provides a roadmap for aligning model capabilities with specific research goals, advocating for integrated, patient-relevant systems to improve therapeutic development. Enhancing model fidelity and interoperability is key to accelerating the bench-to-bedside translation in colorectal cancer care. Full article

Osteosarcoma (OSA) is the most common primary bone malignancy in dogs, characterized by aggressive growth and high metastatic potential. Despite advances in treatment, the prognosis for affected animals remains poor, mainly due to metastatic disease. Metastasis is a complex process that involves forming new blood vessels in the primary tumor (angiogenesis), intravasation, the transport of cancer cells to other locations, extravasation, and the growth of cancer cells in the secondary site. Gold nanoparticles (AuNPs), due to their unique physicochemical properties, are considered promising tools in cancer therapy, both as drug delivery systems and potential anti-metastatic agents. Previously, it has been demonstrated that 500 µg/mL glutathione-stabilized gold nanoparticles (Au-GSH NPs) inhibit cancer cell extravasation—one of the steps of the metastatic cascade. This study aimed to evaluate the anti-metastatic properties of Au-GSH NPs through their influence on OSA cell migration, proliferation, and colony formation in vitro, as well as their antiangiogenic properties on the chick embryo chorioallantoic (CAM) model. Additionally, we investigated whether these effects are associated with changes in alpha-2-macroglobulin (A2M) expression, as it was previously demonstrated to play an essential role in the metastatic cascade. Au-GSH NPs significantly inhibited migration and colony formation in canine osteosarcoma cells (from OSCA-8, OSCA-32, and D-17 cell lines) at 200 µg/mL concentrations. Interestingly, at 500 µg/mL, Au-GSH NPs inhibited angiogenesis on the CAM model and cancer cell migration, but fewer colonies were formed. These results may be directly related to the higher efficiency of Au-GSH NPs uptake by OSA cells at the dose of 200 μg/mL than at the dose of 500 μg/mL, as demonstrated using Microwave Plasma Atomic Emission Spectroscopy (MP-AES). Moreover, this is the first study that demonstrates a significant increase in A2M expression in cancer cells after Au-GSH NPs treatment. This study provides new insight into the potential use of Au-GSH NPs as anti-metastatic agents in canine osteosarcoma, indicating that their anti-metastatic properties may be related to A2M. However, further in vitro and in vivo studies are needed to explore the molecular mechanism underlying these effects and to evaluate the clinical relevance of AuNPs in veterinary oncology. Full article