*2.5. Crystal Violet Assay*

Crystal violet assay was performed as previously described [11]. Briefly, cells were grown in a 96-well plate and left under basal condition or stimulated as mentioned before. Cells were fixed with 4% paraformaldehyde for 20 min and then stained with a solution

containing 0.1% crystal violet for 20 min. After washing, cells were lysed with 10% acetic acid. The optical density at 595 nm (DO595) of each well was measured with a Microplate Reader (Bio-Rad Laboratories, Inc., Hercules, CA, USA) and was used as a measurement of cell viability.

#### *2.6. Reactive Oxygen Species (ROS) Detection*

ROS were detected as already shown [11]. After treatments, cells were incubated with dihydrorhodamine-123 (10 μM) for 30 min at 37 ◦C with 5% CO2 and recovered in complete medium for 30 min. Cells were lysed in RIPA buffer containing 150 mM NaCl, 10 mM Tris-HCl pH 7.2, 0.1% SDS, 1.0% Triton X-100, 1% sodium deoxycholate and 5 mM EDTA. Samples were centrifuged at 12,000× *g* for 10 min at 4 ◦C and the supernatants were used for ROS detection. As a positive control, cells were treated with tert-Butyl hydroperoxide (tBHP, 2 mM for 30 min). The fluorescence emission signal was recorded using a fluorimeter (RF-5301PC, Shimadzu Corporation, Kyoto, Japan) at excitation and emission wavelengths of 508 and 529 nm, respectively.
