Apoptosis is accompanied by distinct morphological changes at the plasma and organelle membrane level. Involvement of certain lipids in apoptosis has been established; however, we have limited understanding of the specific lipid structures that participate in this process. We used untargeted comparative lipidomics to study the changes in lipid composition during staurosporine-induced apoptosis in HCT-116. Our results revealed that ceramides, dihydroceramides, and sphingomyelins, with defined acyl chains, constitute the majority of changes in the lipidome. Expression levels and activities of enzymes responsible for the biosynthesis of lipids that change suggest that de novo synthesis causes these specific changes. Further analysis of the lipidome during apoptosis in other cancer and non-cancer cell lines suggested that accumulation of ceramides and dihydroceramides is specific to cancer cells. Taken together, our data propose that these molecules are regulated at the lipid-specific level during apoptosis and that this regulation differs between cancer and non-cancer cells.
Time-of-flight mass spectrometry (TOFMS) is one of the simplest and most powerful approaches for mass spectrometry. Realization of the advantages inherent in TOFMS requires innovation in the theory and practice of the technique. Instrumental developments, in turn, create new capabilities that enable applications in chemical measurement. This review focuses on the recent advances in TOFMS instrumentation. New strategies for ion acceleration, multiplexed detection, miniaturized TOFMS instruments, approaches to extend the length of ion flight, and novel ion detection technologies are reviewed. Techniques that change the basic paradigm of TOFMS by measuring m/z based on ion flight distance are considered, as are applications at the frontiers of instrumental performance.
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