Fig. 4

TSA inhibits cell invasion through inactivating Arf1 in HNSCC cells. a The effect of TSA on Arf1 activation measured by GST-VHS-GAT pulldown assays. b Arf1 protein levels and activity in various HNSCC cells determined by Western blotting. c The effects of expression of Arf1DN and Arf1CA on Arf1 activation measured by GST-VHS-GAT pulldown assays. d The effect of expression of Arf1DN and Arf1CA on HNSCC cell invasion measured by Borden chambers pre-coated with Matrigel. e, f The effect of expression of Arf1CA on HNSCC cell proliferation (e) and invasion (f) in the presence or absence of 5 μM TSA. Cell proliferation was measured by MTS within 72 h after drug treatment, and cell invasion was determined by Borden chambers pre-coated with Matrigel. EV: empty vector; Arf1CA: the constitutively active mutant of Arf1; Arf1DN: the dominant negative mutant of Arf1; **p < 0.01