Galectins,
beta-galactoside binding proteins, expressed selectively in human
breast carcinoma are attractive targets to employ
lectin-aimed
therapeutics. We examined
beta-galactoside binding potency of neoplastic cells using
fluorescein-labelled synthetic
glycoconjugates as probes for flow cytometry. As a result, surface
beta-galactoside binding proteins/
galectins were discovered on mouse mammary
carcinoma cells in vitro and in vivo unlike non-malignant cells from the several tissues; and asialo-GM1
ganglioside carbohydrate part--containing probe was the most specific one. However, in liver and lung metastatic cells
galectins seem to be expressed within cytoplasm and/or nuclei.
Galectin expression correlated directly with aggressive tumour potential in the A/Sn transplantable model similar to findings in several human
breast carcinoma cell lines. However,
galectin expression was reduced during tumour progression in more aggressive forms of spontaneous BLRB mammary
carcinomas like it was shown for human
breast carcinoma specimens. Analysis of the histopathological data led, however, to the conclusion that
galectin expression hardly might be a suitable marker of aggressiveness of heterogeneous mammary
carcinomas as the observed level of
galectin expression is influenced by the amount of the stroma in a tumour sample and/or probably,
galectin expression inversely correlates with tumour aggressiveness during the initial and advanced steps of mammary tumour progression. We conclude that surface
beta-galactoside binding proteins/
galectins that are selectively expressed during mouse mammary
carcinoma progression, similarly to human
breast carcinomas, seem to be proper targets for asialo-GM1-vectored cytotoxics and our mouse model system might be a relevant instrument to further test novel modes of anti-
breast cancer therapy.