Matrix calcification of cells treated with control, Pi (2.6 or 3.0 mM), and/or purified porcine ALP (1 unit/mL), as indicated, for 10 days in normal medium. B) Matrix calcification of cells cotreated with control, Fsk (25 µM), PPi (0.1 mM), probenecid (Prob, 1 mM) as indicated in osteogenic medium. C) RT-qPCR analysis of Enpp1 expression from cells treated with control or Fsk (25 µM), or probenecid (1 mM) for 12 days in osteogenic medium. *p < 0.05 compared to control; **p < 0.001 compared to control; #p < 0.0001 compared to Fsk-treated.