Search Results (456)

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

Radiation-induced keratoconjunctivitis sicca (KCS) is a significant late complication in dogs receiving radiation therapy for intranasal tumors, particularly with hypofractionated intensity-modulated radiation therapy (IMRT). This retrospective case-control study was performed to identify anatomical and dosimetric risk factors for KCS in 15 canine patients treated with IMRT delivered in 4–6 weekly fractions of 8 Gy. Orbital structures were retrospectively contoured, and dose–volume metrics (D50) were calculated. Receiver operating characteristic (ROC) curve analysis and odds ratios were used to evaluate the associations between radiation dose and KCS development. Six dogs (33%) developed KCS within three months post-treatment. Statistically significant dose differences were observed between affected and unaffected eyes for the eyeball, cornea, and retina. ROC analyses identified dose thresholds predictive of KCS: 13.8 Gy (eyeball), 14.9 Gy (cornea), and 17.0 Gy (retina), with the retina showing the highest odds ratio (28.33). To ensure clinical relevance, KCS was diagnosed based on decreased tear production combined with corneal damage to ensure clinical relevance. This study proposes dose thresholds for ocular structures that may guide treatment planning and reduce the risk of KCS in canine patients undergoing IMRT. Further prospective studies are warranted to validate these thresholds and explore mitigation strategies for high-risk cases. Full article

Lymphoma is the most common neoplasm of lymphoid tissues in dogs. Exportin 1 (XPO1) is an important major nuclear receptor for exporting proteins and RNA species. The XPO1 upregulation can eliminate some tumor suppressor proteins (TSPs) function upon their nuclear–cytoplasmic export. The XPO1 inhibitor, KPT-335, blocks the translocation of TSPs and restores their function to induce cell cycle arrest, apoptosis, and cell proliferation. This in vitro study aimed to evaluate the XPO1 mRNA and protein expression in canine lymphoma cell lines and confirm the relevance with KPT-335. XPO1 mRNA and protein levels were quantified, and the effect of KPT-335 was assessed by a cell proliferation assay. The results indicated that XPO1 mRNA and protein were highly expressed in 17-71, CLBL-1, CLC, CLGL-90, and UL-1, and were moderately expressed in GL-1, Ema, and Nody-1. All canine lymphoma cell lines showed dose-dependent growth inhibition and decreased cell viability in response to KPT-335, with IC₅₀ concentrations ranged from 89.8–418 nM. The expression levels of XPO1 mRNA and protein were related; however, no correlation was found between those expression levels and the efficacy of KPT-335. These findings suggest that XPO1 may represent a promising target for therapeutic intervention in canine lymphoma. 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

Background/objective: Mucosal melanoma (MM) is a poorly responsive, rare and aggressive subtype with few cases having targetable recurrent driver mutations, although Ras/MAPK and PI3K/AKT/mTOR signaling pathway activations are common. Eventual tumor evasion of targeted therapy continues to limit treatment success. Adequate models are necessary to address therapeutic resistance. The relatively greater incidence of naturally occurring MM in dogs, as well as its comparable clinical and pathological characteristics to human MM, represents an opportunity for study as a human MM patient surrogate. Resistance-promoting crosstalk between Ras/MAPK and PI3K/AKT/mTOR signaling under trametinib inhibition of MEK was studied in canine MM. Emphasis was placed on the suppressive effect of trametinib on cell cycle entry and its potential role in drug resistance. Methods: D-type cyclins were investigated following trametinib treatment of five MM cell lines exhibiting differential drug sensitivities. Signaling pathway activation, proliferation, survival, cell death, and cell cycle were analyzed in the context of D-type cyclin expression. Cyclin D2 expression was manipulated using siRNA knockdown or inducible recombinant overexpression. Results: Trametinib diminished cyclin D1 in all cell lines. While relatively trametinib-resistant MM cells exhibited capacity to upregulate cyclin D2, which promoted proliferation, sensitive MM cells lacked similar cyclin D2 compensation. Inhibition of the compensatory cyclin D2 in resistant cells conferred sensitivity. Induced cyclin D2 overexpression in otherwise trametinib-sensitive MM cells promoted survival. Upregulated PI3K/AKT/mTOR signaling under trametinib treatment was suppressed by mTORC1/2 inhibition, which similarly diminished cyclin D2 response. Conclusions: The compensatory switch from preferential reliance on cyclin D1 to D2 plays a role in MM resistance to MEK inhibition. Full article

Studies worldwide report cutaneous neoplasms in dogs; however, data in the arid regions of Mexico remain scarce. Here we report the main malignant cutaneous neoplasms diagnosed by fine needle aspiration cytology (FNAC), and describe the associations with age, sex and breed in Mexicali. Neoplastic lesions accounted for 25.52% (698/2735) of the cases, of which 56.59% (395/698) were malignant. The highest prevalence was observed in dogs aged 9–12 years (n = 193), intact males (n = 162), and mixed-breed dogs (n = 247). Round cell neoplasms (n = 309), including lymphoma, transmissible venereal tumors (TVT), and mast cell tumors (MCT), were the most common cell lineage. Using dogs aged 0–4 years as the reference group, dogs aged 9–12 years had 0.241 times the odds of developing malignant neoplasms (95% CI: 0.141–0.415, p = 0.0025). Using neutered males as the reference group, intact females showed 2.499 times the odds of developing malignant neoplasms (95% CI: 1.462–4.271, p = 0.0042). Compared to mixed-breed dogs, Schnauzers (OR = 0.161) showed significantly lower odds of malignancy (95% CI: 0.082–0.317, p = 0.0004), while Pitbull Terriers had 1.748 times more chance of present malignant neoplasia (95% CI: 1.014–3.013, p < 0.0001). This study provides significant epidemiological evidence on canine cutaneous neoplasms in an arid region of Mexico, identifying key risk factors and distribution patterns that can guide preventive, diagnostic, and therapeutic strategies tailored to regional characteristics. 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

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

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

Urothelial carcinoma (UC) is one of the most frequent tumors in dogs. Besides cytology, histology, and testing for a BRAF mutation, non-invasive biomarkers would benefit the early detection and therapy of UC. This study aimed to compare the detectability of miRNAs in urine sediment and supernatant and to assess their potential as biomarkers for UC. The study involved two phases with 47 canine samples in total; in a pilot trial, ten different miRNAs (miR-16, 21, 103b, 106b, 146, 155, 182, 221, 222, and 375) were isolated from the urine sediments and supernatants from seven healthy control dogs and seven dogs with UC. In a further step, eight miRNAs were isolated from urine sediments from 18 healthy dogs, 11 dogs with purulent cystitis, and 18 dogs with UC. The detectability of miRNAs was improved when isolated from the urine sediment compared with the supernatant. MiR-16 was not deregulated, and miR-106b showed significantly lower expression in cystitis compared with the control. Lower copy numbers were seen for miR-21, 182, 221, and 222 in cystitis cases compared with the controls and UC, respectively. Deregulation was observed for miR-155 and miR-375 between all three groups. A panel including miR-182, 221, 222, 155, and 375 has the potential to discriminate among all three groups in a two-step approach. 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

Canine mammary tumors (CMTs) are the common tumors in female dogs, and approximately 50% of CMTs are malignant tumors, with abnormal regulation of non-coding RNAs being a critical factor in disease progression. Currently, research on long non-coding RNAs (lncRNAs) regulating CMT development remains limited. This study identified a novel lncRNA, aiming to explore the role of lncRNA LOC610012 in CMTs. In this study, immunofluorescence and Western blot analyses were employed to detect protein expression. LncRNA LOC610012 is downregulated in CMT tissues and cells. Stable cells of LOC610012 were constructed by the lentivirus technique. Through a variety of experimental methods, LOC610012 inhibited the proliferation, invasion, and metastasis of CMT cells in in vitro and in vivo experiments conducted using cell culture and mouse models. Mechanistically, LOC610012 regulated the expression of EP3 and GSK-3β by targeting PTGS2, resulting in excessive production of reactive oxygen species (ROS), which inhibited cell viability. Similarly, through transmission electron microscopy, mitochondrial damage caused by LOC610012 was observed in CMT cells, which was manifested as mitochondrial swelling, membrane rupture, and mitochondrial ridge disappearance. PTGS2 could partially restore the inhibition of LOC610012 on cell activity. LOC610012 acts as a tumor suppressor gene in CMTs and as a potential biomarker for the disease. Full article

Background: Canine oral melanoma (COM) is an aggressive and often fatal neoplasm in dogs, with clinical and molecular similarities to human melanoma. Despite its relevance as a comparative oncology model, the molecular mechanisms underlying COM remain poorly understood. This study aimed to characterize gene expression profiles in COM to identify differentially expressed genes (DEGs), potential biomarkers, and therapeutic targets. Methods: In this pilot study, we performed RNA sequencing (RNA-seq) on tumor and healthy oral tissue samples from dogs. Two independent analytical pipelines—Bowtie2-DESeq2 and HISAT-StringTie-Ballgown—were used to ensure robustness in DEG detection. We also conducted pathway enrichment and isoform-level analyses to investigate biological processes and alternative splicing events. Results: Both approaches identified a core set of 929 common DEGs. Key oncogenic pathways, including MAPK/ERK and cell cycle regulation, were significantly affected, with notable upregulation of BRAF, NRAS, CDK4, and MITF (log2FC = 2.86, p < 0.001). The transcription factor SOX10 and the cytokine IL-33, both previously implicated in melanoma progression, were consistently overexpressed. Additionally, NF1, a known RAS pathway inhibitor, was also upregulated. Isoform analysis revealed novel transcript variants, suggesting a complex layer of post-transcriptional regulation in COM. Many DEGs remained uncharacterized, and chromosomal distribution analysis highlighted potential genomic influences. Conclusions: Our findings provide new insights into the molecular landscape of COM, reinforcing its utility as a model for human melanoma. The identification of conserved oncogenic pathways and novel transcript variants opens avenues for further functional studies and the development of targeted therapies in both veterinary and human oncology. Full article