Four new pairs of canine mammary carcinoma cell lines derived from both primary and metastatic lesions were established. The cells were cultured in RPMI-1640 with 10% fetal bovine serum and they showed stable growth for more than 120 passages. Using these cell lines, the expression of E-cadherin was measured by flow cytometry and the function of E-cadherin was evaluated by cell aggregation assay and results from the primary and metastatic lesions were compared statistically. E-cadherin was strongly expressed in all of the cell lines, without a notable difference between cells of primary and metastatic origin. In the cell aggregation assay, the function of E-cadherin was significantly weaker in the cells of primary origin (p < 0.05), as compared with cells of metastatic origin. The present results suggest that a reduction in E-cadherin function may be implicated in the invasive and metastatic potential of canine mammary tumour cells; however, further study will be needed to clarify E-cadherin function in the context of the metastasis of canine mammary carcinoma.

ABSTRACT. Eight new feline mammary adenocarcinoma cell lines derived from either primary or metastatic lesions were established. The morphology of all the cell lines was epithelioid and round to spindle in shape, with cell growth occurring in a monolayer fashion. On immunohistochemistry, these cells reacted with anti-keratin and anti-vimentin antisera. The doubling time of these cells was between 19 and 54 hr. Tumor masses were developed in nude mice by subcutaneous inoculation of the cells that were histologically identical to their original mammary tumor lesions. Telomerase activities measured using the telomeric repeat amplification protocol assay revealed high telemetric activity in all of the cells. KEY WORDS: feline, mammary tumor cell line, primary and metastatic lesion.J. Vet. Med. Sci. 67(12): 1273-1276, 2005 Feline mammary cancer (FMC) is the third most common neoplasm following hematopoietic and skin tumors [1,6]. Most cases of FMC are histologically adenocarcinoma [3]. This tumor shows local infiltrative-destructive growth and frequently metastasizes to the regional lymph nodes, lung and pleura in the early stages of disease [6,15]. Establishment of cell lines from FMC has been conducted, however the number of established cells has been limited [2,8,10], suggesting that the establishment of FMC cell lines is difficult compared to those of other animal species. FMC has many features, including specific biological behaviors and histopathological appearance as well as poor prognosis, and may be an attractive model for research on human breast cancer [7,9,15]. We report herein the establishment and characterization of eight FMC cells derived from either primary or metastatic lesions of five cats with spontaneous FMC.Tissue samples were obtained from 13 cats with FMC admitted to the Veterinary Hospital at the University of Tokyo (Fig. 1). Tumor cells were collected from the surgical specimen or by thoracocentesis in the cats with thoracic metastasis. Tissue samples were placed in 50-ml tubes with phosphate buffer solution (PBS) supplemented with 0.2-mg/ ml gentamycin sulfate (Sigma Chemical Co., St. Louis, MO, U.S.A.) and kept overnight at 4°C. They were then minced into 1-to 2-mm 3 pieces and digested with collagenase mixed solution of DNase and pronase (Sigma Chemical Co.) for 1 hr at 37°C under constant stirring. The digested cells were then incubated in RPMI 1640 (Nissui Pharmaceutical Co., Tokyo, Japan) supplemented with 20% fetal bovine serum (FBS) (Equitech-Bio Inc., Ingram, TX, U.S.A.), 0.01 mg/ml L-glutamine (Nissui Pharmaceutical Co.), fungizone (Gibco BRL., Grand Island, N.Y., U.S.A.) and 5 mg/l gentamycin sulfate (Sigma Chemical Co.), and incubated at 37°C in a humidified atmosphere of 5% CO 2 . Cells collected from pleural effusion were centrifuged and washed with PBS, then cultured under the same conditions described above. After the 10th passages, when cell growth seemed to be stable, the concentrations of FBS in the culture medium were decreased from 20% to 10%.Eight feline mammary adenoca...

The expression of sialyl Lewis X (sLe(x)) in 93 canine and 15 feline mammary gland tumors (MGT) obtained by surgical resection at Veterinary Medical Center, the University of Tokyo was examined by immunohistochemistry. Their clinicopathological features and prognosis were also reviewed. Approximately 60% of MGT tissues showed sLe(x) positive expressions, while all normal mammary gland tissues were negative. However, its expression was not correlated with clinicopathological features and prognosis significantly. This study suggests that sLe(x) may be a tumor-associated antigen in canine and feline MGTs.

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ABSTRACT. Protein expression and subcellular localization of E-cadherin, α-catenin, and β-catenin in 8 feline mammary tumor cell lines were examined by western blot analysis and fluorescence immunocytochemistry. A low E-cadherin expression was observed in FNNm cells. Furthermore, compared to other cell lines, two E-cadherin bands existed in FMC-p1 cells and were localized in the perinuclear region; distinct radial lines were observed in the cytoplasm. A low α-catenin expression was observed in FON-m cells, but there were no apparent abnormalities in its localization. In contrast, similar levels of β-catenin expression and cytoplasmic localization were observed in all cell lines.KEY WORDS: α-and β-catenin, E-cadherin, feline mammary tumor.J. Vet. Med. Sci. 69(8): 831-834, 2007 Cellular adhesion molecules are important for maintaining tissue structure and cell polarity, and are involved in cell movement and proliferation [13]. E-cadherin associates with a group of intracellular proteins termed catenins. α-Catenin serves as a bridge between E-cadherin and β-catenin, both of which connect with the microfilament cytoskeleton [20]. Disruption of normal cell-cell adhesion by alterations in cadherin-catenin molecules may contribute to enhanced migration and proliferation of tumor cells, thereby leading to invasion and metastasis [13].In human and experimental animal models, loss of E-cadherin expression was reported to cause cell migration or metastasis of tumor cells in breast cancers [11], gastric cancers [2], colorectal cancers [9], and prostate cancers [4]. Along with abnormalities of E-cadherin, the relationship between the disruption of the cell adhesion system and α-and β-catenin expressions was also reported in these cancers [7,8,17]. In addition to cell adhesion, β-catenin plays a role in the Wnt signaling cascade that regulates many cellular processes, including cell fate decisions and cell proliferation In cats, mammary tumors are the third common neoplasms, following skin tumors and lymphomas, and account for 12% of all tumors and 17% of the tumors in queens [15]. More than 80% of feline mammary tumors showed considerable malignancy along with rapid progression and metastasis at an early stage [12]. Since feline mammary tumors have malignant properties, investigating their carcinogenesis, tumor progression mechanisms, and the expressions of tumor related molecules is extremely essential. The purpose of this study was to investigate the expression and subcellular localization of E-cadherin, α-catenin, and β-catenin in 8 feline mammary tumor cell lines in order to evaluate the abnormalities of these cell adhesion molecules.In the present study, we used 8 feline mammary tumor cell lines, FKN-p, FMC-p1, FMC-p2, FMC-m, . Of these, 5 were established from a primary lesion, and 3 were established from a metastatic lesion in feline patients bearing spontaneous mammary tumors. Capital letters such as "FKN" indicate identical patients, and small letters such as "p" and "m", indicate primary and metastatic lesions, ...