BIX-01294-induced autophagy regulates elongation of primary cilia.

Previously, we showed that BIX-01294 treatment strongly activates autophagy. Although, the interplay between autophagy and ciliogenesis has been suggested, the role of autophagy in ciliogenesis is controversial and largely unknown. In this study, we investigated the effects of autophagy induced by BIX-01294 on the formation of primary cilia in human retinal pigmented epithelial (RPE) cells. Treatment of RPE cells with BIX-01294 caused strong elongation of the primary cilium and increased the number of ciliated cells, as well as autophagy activation. The elongated cilia in serum starved cultured cells were gradually decreased by re-feeding the cells with normal growth medium. However, the disassembly of cilia was blocked in the BIX-01294-treated cells. In addition, both genetic and chemical inhibition of autophagy suppressed BIX-01294-mediated ciliogenesis in RPE cells. Taken together, these results suggest that autophagy induced by BIX-01294 positively regulates the elongation of primary cilium.