Expression of glyoxalase I and II in normal and breast cancer tissues

The present work aimed to study the activities of glyoxalase system enzymes , glyoxalase I (G I) and glyoxalase II (G II), as well as the expression of their genes in human breast carcinoma. Samples of tumoral tissue and norma l counterparts were drawn from several patients during surgery. They served either for preparing extracts to be used in enzyme activity evaluations or for RNA extraction and subsequent northern blot analysis. A far higher act ivity level of G I and G II occurs in the tumor compared with pair-matched normal tissue, as shown by both spectrophotometrical assay and electrophore tic pattern. Such increased activities of G I and G II likely result from a n enhanced enzyme synthesis as a consequence of increased expression of the respective genes in the tumoral tissue, as evidenced by northern blot. The present findings confirm a key-role of glyoxalase system to detoxify cytot oxic methylglyoxal and modulate S-D-lactoylglutathione levels in tumor cell s. Moreover, they suggest a possible employment of GI inhibitors as anti-ca ncer drugs.