Influence of E-cadherin genetic variation in canine mammary tumour risk, clinicopathological features and prognosis

Establishment of stable expression of firefly luciferase and EGFP in a canine inflammatory mammary carcinoma cell line and tumor-bearing model in nude mice

Canine inflammatory mammary carcinoma (CIMC) is a type of canine malignant mammary tumor with a poor prognosis and high mortality. We transduced firefly luciferase and enhanced green fluorescent protein (EGFP) into CHMp, a CIMC cell line, and established CHMp-Luc-EGFP cells. We investigated the characteristics of this cell line in vitro and in vivo. CHMp-Luc-EGFP was passaged continuously 75 times, with stable expression of luciferase and EGFP. Compared with the wild-type, CHMp-Luc-EGFP had similar proliferation, metastasis, histopathology characteristics, and expression of E-cadherin, N-cadherin, and Ki-67. A tumor-bearing model was established by implantation of CHMp-Luc-EGFP cells, and the dynamic changes of tumors were visualized and quantified using the IVIS imaging system. In summary, the cell line we established could reflect the biological characteristics of CHMp cells, visualize the tumor progression in vivo, and provide a powerful tool for the study of CIMC.

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.

Single Nucleotide Polymorphism in Prolactin Gene Is Associated With Clinical Aggressiveness and Outcome of Canine Mammary Malignant Tumors

Prolactin (PRL) is a key hormone involved in canine mammary development and tumorigenesis. In this study, the influence of a single nucleotide polymorphism (SNP) in the PRL gene (rs23932236) on the clinicopathological parameters and survival of dogs with canine mammary tumors (CMTs) was investigated. A total of 206 female dogs with spontaneous mammary tumors were enrolled in this study and circulating blood cells were genotyped. This specific SNP was associated with larger size (>3 cm diameter) for malignant tumors (P = .036), tumors with infiltrative/invasive growth pattern (P = .010), vascular invasion (P = .006), and lymph node metastasis (P = .004). Carriers of the variant allele had a shorter overall survival compared to the wild-type population with an overall survival of 18.7 months and 22.7 months, respectively (P = .004). These findings suggest that SNP rs23932236 of canine PRL gene may be used as an indicator for the development of clinically aggressive forms of CMTs.

A Novel Canine Mammary Cancer Cell Line: Preliminary Identification and Utilization for Drug Screening Studies

Canine malignant mammary tumor is a dangerously fatal neoplastic disease with poor survival in female dogs. The aim of this study was to preliminary characterize a novel canine mammary cancer cell line, B-CMT, from canine primary mammary gland tumor, and to utilize it as a cell model for in vitro screening of possible therapeutic drugs. The successfully established cell line, B-CMT, was cultured over 50 passages. B-CMT has a fast proliferation rate, and a population doubling time (PDT) of 33.6 h. The B-CMT cell line lacked human epidermal growth factor receptor-2 (HER-2), estrogen receptors (ER) and progesterone receptors (PR) expression by qRT-PCR. Compared with MDCK cells, CDH1 expression of CMT cell line was significantly decreased or even absent, but GATA3 expression dramatically increased, while TGF-β expression was at a similar level. Interestingly, the B-CMT cell line from canine primary tumor also showed positive hypoxia inducible factor-1α (HIF-1α) results in immunofluorescence (IF), western blot, and qRT-PCR analysis. Ten days post inoculation with EGFP-B-CMT (B-CMT cells stably expressing EGFP), the experimental mice developed palpable soft tissue masses which histologically resembled the canine primary tumor, and was approved to be derived from B-CMT cell line through detection of EGFP by immunohistochemical (IHC) analysis. Moreover, we investigated the cytotoxicity of five drugs to B-CMT cells, and the results showed that rapamycin and imatinib significantly inhibited the proliferation of the cells in vitro within a certain range of concentration. They also induced cell cycle arrest of B-CMT cells at G1 and G2 phase, respectively. In summary, the results of this report showed that B-CMT cell line might serve as a tool for future studies on tumor microenvironment and drug resistance.

Role of Cadherins in Cancer-A Review

Cadherins play an important role in tissue homeostasis, as they are responsible for cell-cell adhesion during embryogenesis, tissue morphogenesis, differentiation and carcinogenesis. Cadherins are inseparably connected with catenins, forming cadherin-catenin complexes, which are crucial for cell-to-cell adherence. Any dysfunction or destabilization of cadherin-catenin complex may result in tumor progression. Epithelial mesenchymal transition (EMT) is a mechanism in which epithelial cadherin (E-cadherin) expression is lost during tumor progression. However, during tumorigenesis, many processes take place, and downregulation of E-cadherin, nuclear β-catenin and p120 catenin (p120) signaling are among the most critical. Additional signaling pathways, such as Receptor tyrosine kinase (RTK), Rho GTPases, phosphoinositide 3-kinase (PI3K) and Hippo affect cadherin cell-cell adhesion and also contribute to tumor progression and metastasis. Many signaling pathways may be activated during tumorigenesis; thus, cadherin-targeting drugs seem to limit the progression of malignant tumor. This review discusses the role of cadherins in selected signaling mechanisms involved in tumor growth. The clinical importance of cadherin will be discussed in cases of human and animal cancers.

A modern look at the molecular-biological mechanisms of breast tumours in dogs

High morbidity and increase in the number of registrations of breast tumours in dogs, their wide application as biological models, discussion of numerous questions of oncogenesis, and the lack of a uniform/unified methodological approach to the study of molecular and biological mechanisms of treatment of cancer determine the relevance of the problem of cancer both in humans and in our domestic companions. The analysis of publications allowed us to establish the following patterns of carcinogenesis. The peculiarities of the biological behaviour of breast tumours depend on their pathomorphological structure. Genetic predisposition to breast cancer is characteristic only in the single breed aspect. Environmental factors are of critical relevance to carcinogenesis : chemical pollutants initiate oncogenesis indirectly – by altering the expression of several receptors, impaired endocrine balance and direct mutagenic effects. Reproductive status plays a key role in the initiation and progression of breast tumours by reducing the expression of estrogen, progesterone and prolactin receptor genes. The inflammatory response that accompanies the neoplasia process is characterized by increased production of cytokines, cyclooxygenase-2, interleukins (IL-1, IL-6, IL-8), vascular endothelial growth receptors, and impaired hemostatic status (oxidative stress), which promotes progression of disease. In breast cancer in dogs, genomic instability leads to genomic aberrations, and subsequently, mutations that support the proliferation, survival and dissemination of neoplastic cells. The initiation and progression of mammary gland tumours is provided by cancer stem cells by disrupting the regulation of precursor cell self-renewal, which also predispose to resistance to chemotherapeutic agents, radiation, and hormonal cancer therapy. The analysis of the publications revealed the major markers of carcinogenesis that could potentially be used as biological targets for the design of modern diagnostic strategies and high-performance therapeutic protocols.

BioDog, biomarker detection for improving identification power of breast cancer histologic grade in methylomics

Aim: Breast cancer histologic grade (HG) is a well-established prognostic factor. This study aimed to select methylomic biomarkers to predict breast cancer HGs. Materials & methods: The proposed algorithm BioDog firstly used correlation bias reduction strategy to eliminate redundant features. Then incremental feature selection was applied to find the features with a high HG prediction accuracy. The sequential backward feature elimination strategy was employed to further refine the biomarkers. A comparison with existing algorithms were conducted. The HG-specific somatic mutations were investigated. Results & conclusions: BioDog achieved accuracy 0.9973 using 92 methylomic biomarkers for predicting breast cancer HGs. Many of these biomarkers were within the genes and lncRNAs associated with the HG development in breast cancer or other cancer types.