Staff Scientist, II Becton, Dickinson and Company Milpitas, California, United States
Disclosure(s):
Cynthia Sakofsky, PhD: No financial relationships to disclose
Introduction/Rationale: Tumor tissue is highly heterogenous, containing varying cell types with multiple functions and characteristics. Unraveling the complexity of this tissue at a single-cell level can provide critical understanding of tumor microenvironments (TME), setting the foundation for informing disease states, targeted therapies and the discovery of drug targets and biomarkers. However, maintaining the integrity of the tumor from the time of collection to the time of analysis remains a major challenge. Necrosis, cell degradation, and undesired alterations of cellular states can profoundly impact the quality and validity of the data, therefore reliable tumor preservation is critical. Common preservation methods typically use cross-linking agents that can damage protein and nucleic acids and compromise data quality.
Methods: Here we highlight a novel long-term cryo-preservation buffer that does not contain cross-linking fixatives, that was used to preserve dissociated human lung cancer cells. The tumor was collected in BD®OMICS-Guard and stored for 24 h at 4oC, then processed to obtain single cells that were directly transferred into the novel cryo-preservation buffer for freezing. The samples were then shipped to a location where single-cell multiomic assays were conducted to simultaneously profile mRNA and protein of individual cells.
Results: Non-supervised clustering revealed 12 distinct cell clusters that included infiltrating lymphocytes (TILs), immune cells, and non-immune tumor cells. Differential gene and protein expression profiles were used to distinguish distinct subpopulations of macrophages., while T cell gene sets of naive, activation, and exhaustion states were used to identify the functional heterogeneity of TILs.
Conclusion: Together these data demonstrate the use of a novel cryopreservation buffer that enables flexible workflows while yielding high-quality data.
