PDGF-C promotes cell proliferation partially via downregulating BOP1

Platelet-derived growth factor C (PDGF-C) is a member of PDGF/VEGF family, which is well-known for important functions in the vascular system. It is widely reported that PDGF-C is able to modulate cell proliferation. However, it is still not very clear about this cell modulating mechanism at the molecular level. In a screening of factors regulated by PDGF-C protein, we fished out a factor called block of proliferation 1 (BOP1), which is a pivotal regulator of ribosome biogenesis and cell proliferation. In this study, we investigated the regulation of BOP1 by PDGF-C and its role in modulating cell proliferation. We found that BOP1 was downregulated at both mRNA and protein levels in cells treated with PDGF-C-containing conditioned medium. On the other hand, BOP1 was upregulated in PDGF-C deficient mice. Furthermore, we confirmed that overexpression of BOP1 inhibited HEK293A cell proliferation, whereas knockdown of BOP1 promoted cell proliferation. The mitogenic effect of PDGF-C could be attenuated by downregulation of BOP1. Our results demonstrate a clear PDGF-C-BOP1 signaling that modulates cell proliferation.