*3.2. Cell Culture*

Human colorectal carcinoma HT-29 (ATCC® no. HTB-38™) and HCT 116 (ATCC® CCL-247™) were cultured in McCoy's 5A medium, supplemented with 10% FBS and 1% penicillin-streptomycin solution; breast cancer MCF-7 (ATCC® no. HTB-22™) or melanoma SK-MEL-28 (ATCC® no. HTB-72™) cells were maintained in MEM medium with 10% FBS and 1% penicillin-streptomycin solution. The cell cultures were maintained at 37 ◦C in humidified atmosphere containing 5% CO2. Every 3–4 days, the cells were detached with 0.25% trypsin/0.05 M EDTA for 1–3 min and 10–20% of the harvested cells were transferred to a new flask containing fresh complete culture media.
