migration was monitored as wound healing assay on a Zeiss Cell Observer
HS widefield microscope with a 10× objective. A total of 9 ×
105 cells mL–1 of the respective HEK293
stable cell lines were seeded into fibronectin-coated plates (Corning)
and allowed to settle for 20 h in the presence of tetracycline. The
plates were manually equipped with migration inserts for self-insertion
(Ibidi) by placing the insert with sterile tweezers and gently pressing
it onto the plate. Cell culture dishes and matrix component-precoated
plates were used according to the information in the text. On the
day of experimentation, new growth medium was added containing 7.5%
(v/v) FBS (Sigma), and the inserts were gently removed with sterile
tweezers. Dishes were kept at 37 °C, and pictures of the wound
gap were taken at 0 and 1.5 h time points, using Zeiss ZEN software.
All pictures were analyzed with Fiji software according to length
(unit) difference of the remaining wound gap and presented as speed
of migration (unit/h). Independent experiments were performed at least
in triplicate.