RARα2 upregulates and physically binds with iPS reprogramming genes and promotes colony formation in MM cell lines. (A-B) The expression of Oct4, Sox2, Nanog, and Lin28A genes was examined in OCI-MY5, ARP1, KMS11, and ARK MM cells over- or underexpressed RARα2 by RT-PCR. (C) Western blots exhibited Nanog expression in RARα2 OE and EV OCI-MY5 and ARP1 cells. (D) Total lysates were prepared from HEK-293 cells transiently transfected with the constructs indicated. Co-IP was performed with anti-Flag antibody (left) or anti-V5 antibody (right), followed by western blotting with the antibodies indicated. Control IgG was used as a negative control for the Co-IP. A total of 1% of the lysate used for Co-IP was used as input. Co-IP was repeated in both directions using OCI-MY5 cells to demonstrate interaction of RARα2 with Nanog in the presence of benzonase. (E) The clonogenic capacity was compared between RARα2-OE and EV cells of OCI-MY5 and ARP1 lines (magnification ×40).