Expression of Metallothionein and Vascular Endothelial Growth Factor Isoforms in Breast Cancer Cells

Metallothioneins (MTs) are low-molecular-weight and cysteine-rich proteins that bind heavy metal ions and oxygen-free radicals. MTs are commonly expressed in various tissues of mammals and are involved in regulation of cell proliferation and differentiation, and may be engaged in angiogenesis. Expression of MTs has been studied in many cancer types, especially breast cancer. The research results indicate that MTs may play important, although not yet fully known, roles in cancer angiogenesis. The aim of this study was to analyze the level of gene expression of selected MT isoforms induced with zinc ions in correlation with vascular endothelial growth factor (VEGF) isoforms in in vitro models of breast cancer.

The studies were carried out in three breast cancer cell lines (MCF-7, SK-BR-3, MDA-MB-231). An epithelial cell line derived from normal breast tissue (Me16c) was used as a control. The levels of expression of selected MT isoforms and selected genes involved in angiogenesis were studied with real-time PCR.

Expression of different MT isoforms was induced by zinc ions to differing degrees in individual breast cancer cell lines. An increase in the expression of some MT isoforms was associated with a slight increase in the level of expression of VEGFA.

The research results may indicate certain correlation between an increased expression of selected MT isoforms and a pro-angiogenic factor VEGF in specific types of breast cancer cells.