Correlated fluorescence microscopy and multi-ion beam secondary ion mass spectrometry imaging reveals phosphatidylethanolamine increases in the membrane of cancer cells over-expressing the molecular chaperone subunit CCTδ

Abstract

Changes in the membrane composition of sub-populations of cells can influence different properties with importance to tumour growth, metastasis and treatment efficacy. In this study, we use correlated fluorescence microscopy and ToF-SIMS with C60+ and (CO2)6k+ ion beams to identify and characterise sub-populations of cells based on successful transfection leading to over-expression of CCTδ, a component of the multi-subunit molecular chaperone named chaperonin-containing tailless complex polypeptide 1 (CCT). CCT has been linked to increased cell growth and proliferation and is known to affect cell morphology but corresponding changes in lipid composition of the membrane have not been measured until now. Multivariate analysis of the surface mass spectra from single cells, focused on the intact lipid ions, indicates an enrichment of phosphatidylethanolamine species in the transfected cells. While the lipid changes in this case are driven by the structural changes in the protein cytoskeleton, the consequence of phosphatidylethanolamine enrichment may have additional implications in cancer such as increased membrane fluidity, increased motility and an ability to adapt to a depletion of unsaturated lipids during cancer cell proliferation. This study demonstrates a successful fluorescence microscopy-guided cell by cell membrane lipid analysis with broad application to biological investigation. Graphical abstract

Cell and Tissue Imaging by TOF-SIMS and MALDI-TOF: An Overview for Biological and Pharmaceutical Analysis

“…Furthermore, Fletcher et al employed a TOF-SIMS J105 instrument equipped with 40 kV C 60 + and a CO 2 gas cluster ion beam (GCIB) to visualize, accurately, intact lipids from single cells. They proved that a change in chaperonin-containing tailless complex polypeptide (CCTδ), associated with cell growth and proliferation, implies morphological changes mainly in lipid composition, fluidity, and in amplifying membrane curving (Fletcher et al, 2021).…”

Fusing ToF‐SIMS Images for Spatial‐Spectral Resolution Enhancement using a Convolutional Neural Network

“…[ 16 ] Other groups have simply visualized complementary images as overlays and completed correlative analyses, also referring to these workflows as fusion methods. [ 17–19 ]…”

“…[16] Other groups have simply visualized complementary images as overlays and completed correlative analyses, also referring to these workflows as fusion methods. [17][18][19] While many of these approaches have proven useful, and have demonstrated enhanced ion image resolution, they are not suitable for the fusion of two hyperspectral ToF-SIMS imaging data sets. This is because the fusion of individual ion images will be ineffective when two or more high mass resolution peaks correspond to a single low mass resolution peak, the exact problem we are attempting to address in this work.…”

Successive High-Resolution (H2O)n-GCIB and C60-SIMS Imaging Integrates Multi-Omics in Different Cell Types in Breast Cancer Tissue

“…geneity at the single cell level. Several groups tackled this issue by integrating MSI with immunofluorescence imaging, 13,14 conventional histology, 15 and machine learning. Multiplexed ion-beam imaging SIMS has also been established to improve conventional histological approaches.…”

“…Although MSI has generated more detailed chemical maps of cancer tissue, there is still a dearth of information on the immune-landscape, phenotype, cell classification, and heterogeneity at the single cell level. Several groups tackled this issue by integrating MSI with immunofluorescence imaging, , conventional histology, and machine learning. Multiplexed ion-beam imaging SIMS has also been established to improve conventional histological approaches.…”