Single-cell sphingosine kinase activity measurements in primary leukemia

Area of Science:

• Oncology
• Biochemistry
• Cell Biology

Background:

• Sphingosine kinase (SK) is a key enzyme in cancer, particularly leukemia.
• Traditional bulk analysis of SK activity masks critical cellular differences.
• Understanding SK heterogeneity is vital for effective cancer therapy.

Purpose of the Study:

• To measure SK activity at the single-cell level in various leukemia types.
• To characterize the heterogeneity of SK activity and sphingosine metabolism in leukemia cells.
• To evaluate the utility of single-cell analysis for studying oncogenic signaling in cancer.

Main Methods:

• Utilized a fluorescent sphingosine reporter for single-cell SK activity measurement.
• Employed automated capillary electrophoresis (CE) for rapid separation and quantification.
• Analyzed tissue-cultured K562 cells, primary PBMCs from leukemia patients, and enriched AML blasts.

Main Results:

• Observed significant intercellular heterogeneity in reporter phosphorylation (up to 10-fold differences).
• Quantified varying levels of reporter uptake and metabolite formation across single cells.
• Demonstrated persistent SK activity diversity even in highly purified leukemic blasts.

Conclusions:

• Single-cell analysis reveals substantial heterogeneity in SK activity within leukemia.
• This variability has implications for the efficacy of SK inhibitors in leukemia treatment.
• Single-cell approaches are essential for detailed characterization of cancer signaling pathways.