*4.9. F-Actin Cytoskeleton Immunofluorescence*

Following the same experimental protocol of treatment as described above, LCLs and DLBCLs cells were collected and washed with DPBS. After washing, they were fixed with 4% paraformaldehyde for 10 min at RT and washed with DPBS. Actin fibers were revealed using 405-Phalloidin-iFluor reagent (Abcam) as per the manufacturer's instructions.

Finally, after 30 min of phalloidin incubation, nuclei were stained with TOPRO-3 (1:1000—Fisher scientific) for 15 min at RT. Cells were visualized using a ZEISS LSM 900 confocal microscope (40 × oil lens). Images were constructed using the Fiji software. For actin quantification by flow cytometry, the same experimental protocol was followed. Intracellular actin fibers labeling (45 min of phalloidin staining) was performed after

permeabilization (IntraPrep Permeabilization Reagent kit–Beckman Coulter) according to the protocol recommended by the supplier. Acquisitions were performed on the Cytoflex cytometer (Beckman Coulter). Results were analyzed with Kaluza Analysis 2.1 Software. Fold change was calculated based on the mean fluorescence intensity ratio of phalloidin of the test normalized to the control.
