IJUP08 - Universidade do Porto

In vitro and in vivo studies of the expression of carbohydrates in
a canine mammary carcinoma cell line
J. Gomes 1 , C. Lopes 2 , E. Hellmén 3 , C. Reis 1,4 and F. Gärtner 1,2
1 Institute of Molecular Pathology and Immunology of the University of Porto, Portugal;
2 Instituto de Ciências Biomédicas Abel Salazar, University of Porto, Portugal;
3 Department of Anatomy, Physiology and Biochemistry, Uppsala, Sweden;
4 Medical Faculty of Porto, Porto, Portugal.
Spontaneous mammary tumours are the most common neoplasia in the female dog and
have a high biological and histomorphological heterogeneity. Approximately one-half of
all mammary tumours in dogs are malignant and have a great potential to metastasize to
the regional lymph nodes or other organs such as the lungs [1]. Malignant transformation is
associated with abnormal glycosylation, resulting in the synthesis and expression of altered
carbohydrates determinants. Although the majority of cancer research in humans is
conducted using established cell lines, the interaction between the tumour and the host
organism must be taken in consideration, so the results need to be confirmed using animal
models. In order to study the biology of canine mammary tumours we used a previously
established canine mammary cell line [2] and compared the information with an in vivo
model.
The CMT-U27 cell line, derived from a ductular carcinoma, was cultured and kept at 37ºC
in 5% CO2 atmosphere. Cells were stained for expression of carbohydrates by
immunoflurescence. In vivo experiments were performed using mice 6 weeks old of
N:NIH(s)II-nu/nu strain. Tumours and organs which had been removed from these mice
were fixed in 10% neutral-buffered formalin and embedded in paraffin for histopathology
and immunohistochemistry studies.
The CMT-U27 cells adhered to the bottom of the flask in single or paired cells as a
compact thin monolayer. Immunoflurescence for carbohydrates showed reaction for anti-
SLe x , anti-Le x and anti-Le a antisera. The CMT-U27 cells grew when inoculated
subcutaneously in the fat mammary pad of female nude mice. Tumour masses were
histologically identical to the primary mammary tumour lesions, and when
heterotransplanted tumours were re-cultured, the expression of carbohydrates was not
altered. To look for metastatic targets tissues we performed an intravenous injection in the
tail vein of the mice. These cells metastasised to lymph nodes, lungs, heart, spleen, kidney
and liver.
The pattern of expression of carbohydrates in the canine mammary carcinoma cell line
suggests that these antigens could be useful as a prognostic tumour marker in canine
mammary tumours. The aberrant expression of carbohydrates may also play a fundamental
role in the molecular mechanisms of metastization to distant organs and facilitate positive
interactions within the target organ.
References:
[1] Moulton, J.E. (1990), Tumors of the mammary gland. In Tumors in Domestic Animals, 3rd edn.
Ed J.E. Moulton. Berkeley, University of California Press, 518-552.
[2] Hellmén, E. (1992), Characterization of four in vitro established canine mammary carcinoma
and one atypical benign mixed tumor cell lines. In Vitro Cell Dev Biol, 28A, 309-19.
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