Combination of Droplet Extraction and Pico-ESI-MS Allows the Identification of Metabolites from Single Cancer Cells

Abstract

We have combined droplet extraction and a pulsed direct current electrospray ionization mass spectrometry method (Pico-ESI-MS) to obtain information-rich metabolite profiling from single cells. We studied normal human astrocyte cells and glioblastoma cancer cells. Over 600 tandem mass spectra (MS) of metabolites from a single cell were recorded, allowing the successful identification of more than 300 phospholipids. We found the ratios of unsaturated phosphatidylcholines (PCs) to saturated PCs were significantly higher in glioblastoma cells compared to normal cells. In addition, both isomeric PC (17:1) and (phosphatidylethanolamine) PE (20:1) were found in glioblastoma cells, whereas only PC (17:1) was observed in astrocyte cells. Our method paves the way to characterize the chemical contents of single cells, providing rich metabolome information. We suggest that this technique is general and can be applied to other life science studies such as differentiation and drug resistance of individual cells.

Single-cell lipidomics with high structural specificity by mass spectrometry

“…Among those omics, the proteome and metabolome respond to external stimuli more rapidly and usually are harder to be detected or identified due to their complex structures and low biomarker abundances in a single cell 11 . Mass spectrometry (MS) has become a method of choice for single-cell metabolome analysis in consideration of its high sensitivity and high structural identification capabilities [12][13][14][15][16][17][18][19][20] .…”

Advances in mass spectrometry based single-cell metabolomics

“…A subsequent study employed pulsed direct current ESI-MS liquid microextraction to allow more spectra to be recorded from each cell. 21 Using this approach, the authors were able to acquire over 600 MS/ MS spectra from a single cell. It was found that the number of unsaturated phospholipids increased in glioblastoma cells compared to normal astrocyte cells.…”

“…It was found that the number of unsaturated phospholipids increased in glioblastoma cells compared to normal astrocyte cells. 22 A different route for desorbing material from single cells on a surface is to use laser desorption. In laser desorption/ionization droplet delivery (LDIDD) MS a focused UV laser is directed towards the cell surface to desorb/ionize the cell components.…”

New mass spectrometry technologies contributing towards comprehensive and high throughput omics analyses of single cells

“…Zhang and coworkers recently described a combined droplet extraction and a pulsed direct current ESI-MS method to record over 600 tandem mass spectra from a single human astrocyte cell and identified over 300 phospholipids. 143 Yin et al extracted picoliter volumes of material from live Allium cepa cells using electroosmotic extraction and a hydrophobic MS compatible electrolyte followed by nano-ESI analysis to identify more than 50 metabolites. 144 Efficient partitioning of hydrophilic and hydrophobic analytes was observed into the aqueous and hydrophobic electrolyte phase respectively providing additional insight on the molecular properties.…”