Magnesium intracellular content and distribution map in drug-resistant and -sensitive whole cells

Magnesium (Mg) plays crucial structural and regulatory roles within cells. Despite the extensive amount of data about the biochemistry of Mg, a complete picture of its regulation and cellular homeostasis is lacking. Thanks to recent improvements in third generation synchrotron X-ray sources, X-ray fluorescence microscopy (XRFM) is becoming a highly sensitive method for mapping elemental distributions in cells. XRFM maps the element content but not the concentration, which is a relevant variable in a biological context. We tackled this issue by combining XRFM with atomic force microscopy that was used to obtain morphological information of the sample. The aim of the present study was to compare the content and the distribution of Mg in drug-resistant and -sensitive tumor cell lines. Our data has shown a massive increase of Mg in LoVo drug-resistant cells. Moreover, the map of intracellular Mg showed marked differences in the pattern distribution between sensitive and resistant cells.