1 research outputs found
MALDI-TOF MS Imaging of Metabolites with a <i>N</i>‑(1-Naphthyl) Ethylenediamine Dihydrochloride Matrix and Its Application to Colorectal Cancer Liver Metastasis
Matrix-assisted
laser desorption/ionization mass spectrometry imaging (MALDI MSI)
is a label-free technique for identifying multiplex metabolites and
determining both their distribution and relative abundance in situ.
Our previous study showed that <i>N</i>-(1-naphthyl) ethylenediamine
dihydrochloride (NEDC) could act as a matrix for laser desorption/ionization
time-of-flight mass spectrometry (LDI-TOF MS) detection of oligosaccharides
in solution. In the present study, NEDC-assisted LDI-TOF MSI yielded
many more endogenous compound peaks between <i>m</i>/<i>z</i> 60 and <i>m</i>/<i>z</i> 1600 than
9-aminoacridine (9-AA). Our results show that NEDC-assisted LDI-TOF
MSI is especially well-suited for examining distributions of glycerophospholipids
(GPs) in addition to low molecular weight metabolites below <i>m</i>/<i>z</i> 400. Particularly, NEDC matrix allowed
the LDI-TOF MSI of glucose in animal tissue. Furthermore, NEDC-assisted
LDI-TOF MSI was applied to a mouse model of colorectal cancer liver
metastasis. We revealed the distinct spatio-molecular signatures of
many detected compounds in tumor or tumor-bearing liver, and we found
that taurine, glucose, and some GPs decreased in tumor-bearing liver
as the tumor developed in liver. Importantly, we also found a glucose
gradient in metastatic tumor foci for the first time, which further
confirms the energy competition between tumors and liver remnant due
to the Warburg effect. Our results suggest that NEDC-assisted LDI
MSI provides an in situ label-free analysis of multiple glycerophospholipids
and low molecular weight metabolites (including glucose) with abundant
peaks and high spatial resolution. This will allow future application
to in situ definition of biomarkers, signaling pathways, and disease
mechanisms