BMV109 Pan Cathepsin probe (Vergent Bioscience) and DQ red BSA (Invitrogen) were added to each well at a final concentration of 1µM and 10µG/mL, respectively, and cells were incubated at

37°C for 1-hour.

Cells were washed 3 x DPBS +/+ and fixed for 10 minutes at room temperature in Invitrogen^TM eBioscience^TM Intracellular Fixation buffer.

Cells were washed 3 x DPBS+/+ and incubated in 1 μg/ml DAPI (Life Technologies) for 10 minutes at room temperature in DPBS+/+.

Cells were imaged using an EVOS^TM M7000 (Invitrogen) at 20 x magnification. Image analysis was performed using Cellprofiler 4.2.5.