Streptomycin mixture solution

HeLa cells were maintained in tissue culture polystyrene Petri dishes (Sarstedt, Germany) in a humidified incubator (37 °C, 5% CO₂) in Dulbecco’s modified Eagle’s medium supplemented with 10% fetal bovine serum (S13665S181H, Biowest SAS, France), 4 mM L-glutamine (G7513, Merck, Germany), 100 U/ml penicillin and 100 μg/ml streptomycin mixture solution (Merck, Germany).

HeLa Fucci cells (RCB2812, RIKEN BRC) were maintained in Dulbecco's Modified Eagle's Medium (DMEM, 31,885 Gibco) supplemented with 10% Fetal Bovine Serum (Biowest SAS, France), 100 U/ml penicillin, and 100 μg/ml streptomycin mixture solution (Merck, Germany), in a humidified incubator at 37 °C and 5% CO₂. Before the experiment cells were detached from a tissue culture Petri dish using standard protocol (0.05% (w/v) trypsin, 0.02% (w/v) EDTA solution). Cells were picked up in a 1 ml culture medium, and 50 µl of cell suspension containing ~ 1.5 × 10⁵ cells was transferred to each well of a 6-well tissue culture plate filled with a completed culture medium. The 6-well culture dish was placed into an incubator for 24 h to let HeLa Fucci cells adhere to the bottom of the dish. During measurements, only single cells were considered without contribution to large and dense clusters.

HeLa cells were cultured in tissue culture polystyrene Petri dishes (Sarstedt, Germany) in a humidified incubator (37 °C, 5% CO₂) in Dulbecco’s modified Eagle’s medium (DMEM), supplemented with 10% fetal bovine serum (Biowest SAS, France), 4 mM l-glutamine (Merck, Germany), 100 U/ml penicillin and 100 μg/ml streptomycin mixture solution (Merck, Germany). Cells were passaged by using 0.05% (w/v) trypsin and 0.02% (w/v) EDTA solution (Merck, Germany). (The protocols for the employed control cell lines can be found in the Supplementary Information (SI)).
Cell adhesion assay buffer was prepared by adding 20 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) to Hank’s balanced salt solution (HBSS). Cells were brought into suspension by using pre-warmed trypsin–EDTA solution. trypsin digestion was terminated by medium addition. Harvested cells were washed two times: centrifuged at 200×g for 5 min to remove the complete culture medium and cell pellet was re-suspended in 20 mM HEPES HBSS buffer. Cells were then counted in a hemocytometer and diluted to a final cell density of 8000 cells in 25 µl of HEPES HBSS solution.