Induced Expression of N-Glycolylneuraminic Acid in B16 Melanoma Cells, Modulates Caveolin-1 and Integrin 5 Expression and Promotes Mesenchymal-Like Morphology

SEGATORI VALERIA INÉS; ALBETÓ, MARINA; GOMEZ, DANIEL; ALONSO DANIEL F; GABRI MARIANO R

Distrito Federal

Congreso; Congreso Latinoamericano de Glicobiología; 2013

Sociedad Latinoamericana de Glicobiología

Caveolin-1 was recently proposed as an antimetastatic marker in melanoma since it is downregulated in malignant phenotypes. In addition, its overexpression reduces the presence of integrin in the highly metastatic B16F10 melanoma cell line. Participation of glycosphingolipids seems to be important in caveolin-1 signaling complex function. In mammalian cells, most prominent sialic acids are N-Acetylneuraminic acid (NAc) and N-Glycolylneuraminic acid (NGc), usually found as terminal constituents of different membrane glycoconjugates such as the GM3 ganglioside (NacGM3 or NGcGM3). Since NGcGM3 is overexpressed in several malignant cancers, we evaluated the participation of GM3 gangliosides in the development of the malignant phenotype. In this regard, we have cloned and transfected B16F0 -low metastatic melanoma cell line- with the mRNA sequence of the cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH), the enzyme that catalyzes NGc synthesis. The resulting cell line was designated B16-H. In these cells, we observed a dramatic down-regulation of the plasma membrane expression of NacGM3 -highly expressed in B16F0 cells- and an increase in the expression of NGcGM3. The presence of NGcGM3 in B16-H cells promotes in vitro cell proliferation and adhesion. We observed that B16-H cells present reduced levels of caveolin-1 in plasma membrane and a positive regulation of Integrin 5. Also, in vitro cultured B16-H cells showed substantial morphological changes from parental B16F0 cells, presenting a spindle type morphology and a decrease in membrane protrusion number. Our results suggest that GM3 ganglioside variants participate in the balance between caveolin and integrin cell membrane expression in the development of malignant phenotype.