PACC1 and autosomal dominant polycystic kidney disease: The antiproliferative effect of 1 nM PAC and 10 nM ATRA treatment on ADPKD cells was comparable to that of 10 or 100 nM PAC treatment alone, indicating that ATRA could reduce the concentration of PAC by 10 to 100 times to achieve similar antiproliferative effects.