A "shotgun" lipidomics strategy consisting of sequential functional group selective chemical modification reactions coupled with high-resolution/accurate mass spectrometry and "targeted" tandem mass spectrometry (MS/MS) analysis has been developed and applied toward the comprehensive identification, characterization and quantitative analysis of changes in relative abundances of >600 individual
glycerophospholipid, glycerolipid,
sphingolipid and
sterol lipids between a primary
colorectal cancer (CRC) cell line, SW480, and its isogenic lymph node metastasized derivative, SW620. Selective chemical derivatization of
glycerophosphoethanolamine and
glycerophosphoserine lipids using a "fixed charge" sulfonium ion containing, d(6)-S,S'-dimethylthiobutanoylhydroxysuccinimide
ester (d(6)-DMBNHS)
reagent was used to eliminate the possibility of isobaric mass overlap of these species with the precursor
ions of all other
lipids in the
crude extracts, thereby enabling their unambiguous assignment, while subsequent selective mild
acid hydrolysis of plasmenyl (
vinyl-ether) containing
lipids using
formic acid enabled these species to be readily differentiated from isobaric mass plasmanyl (alkyl-
ether) containing
lipids. Using this approach, statistically significant differences in the abundances of numerous
lipid species previously identified as being associated with
cancer progression or that play known roles as mediators in a range of physiological and
pathological processes were observed between the SW480 and SW620 cells. Most notably, these included increased plasmanylcholine and
triglyceride lipid levels, decreased
plasmenylethanolamine lipids, decreased C-16 containing
sphingomyelin and
ceramide lipid levels, and a dramatic increase in the abundances of total
cholesterol ester and
triglyceride lipids in the SW620 cells compared to those in the SW480 cells.