The human cervical HeLa and rat H9c2 myoblast cells were grown in Dulbecco's Modified Eagle's Medium (DMEM, PAN Biotech) with added 10 % fetal bovine serum (Sigma Aldrich) as well as 1% 10,000 U/mL penicillin and streptomycin. The medium of incubated cells was removed and cells were resuspended in Dulbecco's Phosphate Buffered Saline (DPBS, PAN Biotech). Next DPBS was removed, and adherent cells were detached with trypsin/EDTA (PAN Biotech) by incubating for 2 min at 37°C and 5% CO2. The cell suspension was diluted with DMEM and spun down (300 g, 5 min). Cell pellets were resuspended in DPBS counted in a hemocytometer to obtain 10 6 cell aliquots and were transferred into 2 mL homogenization tubes. After removing DPBS, cell pellets snap frozen in liquid nitrogen and kept at -80 °C till use.