Comparison of mucin-1 in human breast cancer and canine mammary gland tumor: a review study

Mucin-1 (MUC-1) is a transmembrane glycoprotein, which bears many similarities between dogs and humans. Since the existence of animal models is essential to understand the significant factors involved in breast cancer mechanisms, canine mammary tumors (CMTs) could be used as a spontaneously occurring tumor model for human studies. Accordingly, this review assessed the comparison of canine and human MUC-1 based on their diagnostic and therapeutic aspects and showed how comparative oncology approaches could provide insights into translating pre-clinical trials from human to veterinary oncology and vice versa which could benefit both humans and dogs.

Prognostic impact of alterations in E-cadherin and P-cadherin expression in canine mammary tumors

Expression of cadherins has been correlated to the development and aggressiveness of epithelial neoplasms, however, in canine mammary tumors, their significance prognostic is uncertain. Due to this fact, the expression of the intracellular adhesion molecules E and P-cadherin and correlation with overall survival were analyzed in 25 canine mammary gland tumors. E-cadherin expression reduction was correlated with histological type, high histological grade, and overall survival rate. P-cadherin staining was higher in malignant tumors, unrelated to other clinicopathological features of aggressiveness. The results of this study suggest a relationship between lower expression of E and P-cadherin and worse prognostic in canine mammary tumors, including shorter overall survival.

VEGF-B, VEGF-A, FLT-1, KDR, ERBB2, EGFR, GRB2, RAC1, CDH1 and HYAL-1 Genes Expression Analysis in Canine Mammary Gland Tumors and the Association with Tumor ClinicoPathological Parameters and Dog Breed Assessment

Canine mammary gland tumors (CMTs) are one of the most prevalent cancers in dogs and a good model for human breast cancer (BC), however gene expression analysis of CMTs is scarce. Although divergence of genes expression has been found in BC of different human races, no such research of different dog’s breeds has been done. The purpose of this study was to investigate expression of the VEGF-B, VEGF-A, FLT-1, KDR, ERBB2, EGFR, GRB2, RAC1, CDH1 and HYAL-1 genes of canine mammary carcinomas, compare the expression levels with clinicopathological parameters and analyze expression disparities between different breeds. Carcinomas and adjacent tissues were collected from female dogs to perform routine histopathology, immunohistochemistry (IHC) and quantitative real-time polymerase chain reaction (qRT-PCR). We found that VEGF-B and EGFR genes were overexpressed in the mammary gland carcinomas compared to adjacent tissue. VEGF-B gene expression had associations with different parameters (tumor size, grade, and absence of metastasis). Furthermore, differences in VEGF-B, FLT1, ERBB2, GRB2, RAC1, CDH1 and HYAL-1 genes expression have been found in different breed dogs (German Shepherd, Yorkshire Terrier) and mixed-breed dogs indicating that a dog’s breed could determine a molecular difference, outcome of cancer and should be accounted as a confounding factor in the future gene expression research.

Sox4 Regulates the Sensitivity of Canine Mammary Gland Tumor Cells to Cisplatin via the Wnt/β-catenin Signaling Pathway

Background: The development of cisplatin resistance is one of the major causes of breast cancer treatment failure, and is associated with changes in Sox4 gene expression. In this study, a cisplatin-resistant cell line, CHMpCIS, was constructed from the cell line CHMp, which was isolated from the primary lesion of a malignant canine mammary gland tumor (CMGT). Sox4 expression was evaluated to assess its roles in cisplatin sensitivity, proliferation and apoptosis, epithelial-mesenchymal transition (EMT), cancer stem cell (CSC) features, and activation of the Wnt/β-catenin signaling pathway in CMGT cells.Results: CHMpCIS Cells exhibited changes in morphology, slower proliferation, and greater anti-apoptotic ability, EMT and CSC features, and the Wnt/β-catenin pathway was activated in CHMpCIS cells. In CMGT tissues, Sox4 expression was elevated. In CHMpCIS cells, silencing Sox4 inhibited cisplatin resistance, EMT and CSC features, and Wnt/β-catenin signaling activation. Then activating the Wnt/β-catenin signaling pathway increased Sox4 expression levels.Conclusions: Silencing Sox4 inhibited the above-mentioned cancer cell characteristics in CHMpCIS cells compared with CHMp cells. In addition, activating the Wnt/β-catenin signaling pathway increased Sox4 expression levels, as part of a positive feedback loop. These findings may provide new targets and therapeutic strategies for the clinical treatment of CMGT as well as a reference for human mammary gland tumor (HMGT) research.

Crosstalks Among Cancer Stem Cells and Histopathologic Features in Determining Prognosis in Canine Mammary Gland Carcinomas

The purpose of the present work was the evaluation of the prognostic potential of histopathologic features, cancer stem cells (CSCs), and epthelial-mesenchymal transition (EMT) in relation to lymph node status and lymphovascular invasion (LVI) in canine mammary gland carcinomas (CMGCs). CSCs are proposed as the main cause of tumorigenesis, therapy failure, and recurrence which form a small fraction of tumor bulk. We evaluated presence of micropapillary growth pattern (MGP), infiltration into surrounding tissues (IST), and vasculogenic mimicry (VM) in H&E stained slides of 26 paraffin-embedded tumor samples. Lymph nodes of all cases were assessed. Additionally, they were examined immunohistochemically in terms of vimentin expression as an indicator of EMT which is a well-known mechanism for metastasis, and CD44, CD24, and ALDH1 for CSCs detection. Data analyses showed significant relationships between MGP and CSCs (P = 0.037), VM and CSCs (P = 0.013), lymph node status and CSCs (P = 0.0001), lymph node status and EMT (P = 0.003), IST and LVI (P = 0.05), VM and LVI (P = 0.01), VM and lymph node status (P = 0.007), and LVI and lymph node status (P = 0.04). Results indicated the prognostic value of MGP, VM, and CSCs with respect to confirmed prognostic markers, including LVI and lymph node involvement, in CMGCs.

Scorpion Venom Peptide Effects on Inhibiting Proliferation and Inducing Apoptosis in Canine Mammary Gland Tumor Cell Lines

The most common neoplasms in intact female dogs are CMGTs. BmKn-2, an antimicrobial peptide, is derived from scorpion venom and has published anticancer effects in oral and colon human cancer cell lines. Thus, it is highly likely that BmKn-2 could inhibit CMGT cell lines which has not been previously reported. This study investigated the proliferation and apoptotic properties of BmKn-2 via Bax and Bcl-2 relative gene expression in two CMGT cell lines, metastatic (CHMp-5b) and non-metastatic (CHMp-13a). The results showed that BmKn-2 inhibited proliferation and induced apoptosis in the CMGT cell lines. The cell morphology clearly changed and increased apoptosis in a dose dependent of manner. The half maximum inhibitory concentration (IC50) was 30 µg/mL for CHMp-5b cell line and 54 µg/mL for CHMp-13a cell line. The induction of apoptosis was mediated through Bcl-2 and Bax expression after BmKn-2 treatment. In conclusion, BmKn-2 inhibited proliferation and induced apoptosis in both CHMp-5b and CHMp-13a cell lines via down-regulation of Bcl-2 and up-regulation of Bax relative mRNA expression. Therefore, BmKn-2 could be feasible as candidate treatment for CMGTs.

The establishment of primary cell culture from canine mammary gland tumor

BACKGROUND: In dogs, an insufficient variety of cell lines commercially available or difficulties in obtaining the existing cell lines developed from various studies results in a limited number of cytotoxicity and related molecular studies integrated with clinical practice. Hence, the doses of many drugs or supportive treatments used in canine tumor cases are adjusted based on studies in humans. OBJECTIVE: A cell line was established from a benign mixed tumor of the canine mammary gland. METHODS: Following surgical removal of the tumor, mechanical dissociation, and PBS washing, a culture process of the tumor cells was performed, including the passaging, freezing, and thawing stages. After several passages, the morphological characteristics of the cells at the logarithmic growth phase were observed under a phase-contrast microscope. RESULTS: The microscopy of the cells cultured on plastic dishes revealed monolayer colonies. The average passage time, which was 5–6 days in the first three passages, decreased to 2–3 days after the third passage. Microscopic examination of tumor cells revealed an adherent, stellated, and spindle-shaped structure. CONCLUSIONS: No difference was observed in the viability and morphology of the cells thawed even after the long period of freezing (∼18 months). The different canine cell lines can provide promising molecular applications that can be adapted into practical clinics in veterinary science.