Electrorotation as a tool for the dielectric characterization of tumor plasma cells in multiple myeloma.

Multiple myeloma (MM) is a hematological malignancy characterized by the clonal expansion of tumor plasma cells. Genetic alterations, metabolic adaptations, stress-response pathway activation, and membrane remodeling promote clinical heterogeneity, which complicates treatment and contributes to variable therapeutic outcomes. Given the central role of the plasma membrane in the electrokinetic properties of cells, electrical parameters such as membrane capacitance (Cm) and electrical impedance have emerged as promising, biomarker-independent indicators for cell characterization. Here, we investigated the dielectric properties of three human MM cell lines (HMCLs) with distinct metabolic profiles and sensitivity to proteasome inhibitors. Using a custom electrorotation (ROT) platform, we were able to discriminate HMCLs with different metabolic profiles, stress-responsepathway activity, and sensitivity to proteasome inhibitors. Overall, this proof-of-concept study highlights the potential of ROT as a label-free biophysical approach that may provide a complementary layer for the functional characterization of MM cells.