Figure 6.
Noxa plays a critical role in TSA- and PS-341-induced apoptosis in HNSCC cells. A, Knock-down of Noxa in UMSCC1 and UMSCC23 cells. SCC cells were transfected with Noxa siRNA or control luciferase siRNA using fugene. Cell lysates were probed with anti-Noxa antibodies. α-Tubulin was utilized as an internal control. B, Knock-down of Noxa inhibited PS-341 and TSA-induced apoptosis. Cells were transfected with siRNA as described in A. 48 h after transfection, cells were treated with PS-341 alone or PS-341 and TSA together for 16 h. Cell viability was determined by Trypan blue exclusion assay. The results are average values from three independent experiments (** P < 0.01).