Dulbecco’s modified Eagle’s medium, sodium bicarbonate, antibiotics, dimethyl sulfoxide, and other chemicals, unless otherwise stated, were obtained from Sigma (St. Louis, MO, USA). Fetal bovine serum and trypsin-EDTA were obtained from Fisher Scientific (Waltham, MA, USA). The fluorogenic substrate Z-Gly-Pro-Arg-AMC was purchased from Bachem (King of Prussia, PA, USA). CA074 was purchased from Peptides International (Louisville, KY, USA) and CK inhibitor L-873724 (Compound 1) was obtained from (Merck-Frosst, Canada) (Gauthier et al., 2008 (link)) Compounds 2 (Palmer et al., 2005 (link)), 3 (Yamashita et al., 1997 ), 4 (Altmann et al., 2006 (link)) and 5 (Respondek et al., 2014 (link)) were synthesized using literature protocols. DQ- collagen I substrate was from Life Technologies (Carlsbad, CA, USA) and Cultrex ™ (reconstituted basement membrane; rBM) was from Trevigen (Gaithersburg, MD, USA). Rabbit anti-human CK antibodies were purchased from Abcam (Cambridge, MA, USA) and anti-DDK antibodies were from OriGene (Rockville, MD, USA). Horseradish peroxidase-labeled goat anti-rabbit IgG was from Pierce (Rockford, IL, USA).