*3.8. Cytotoxicity Assay*

The in vitro cytotoxicity of individual substances was evaluated using the MTT assay, which was performed as previously described [23]. Docetaxel was used as a control.

### *3.9. Colony Formation Assay*

The colony formation assay was performed as described before with slight modifications [22]. 22Rv1 cells were treated with the testing compounds for 48 h and then were trypsinized. The number of alive cells was counted with the trypan blue exclusion assay as described before [24]. In total, 100 viable cells were plated into each well of six-well plates in complete fresh medium (3 mL/well) and were incubated for 14 days. Then, the medium was aspirated, and the surviving colonies were fixed with 100% MeOH, followed by washing with PBS, and air-drying at RT. Next, the cells were incubated with a Giemsa staining solution was for 25 min at RT, the staining solution was aspirated, and the wells were rinsed with dH2O and air-dried. The number of cell colonies was counted by naked eye.
