Figure 5. PXD101 treatment induces loss of Rb protein and Rb phosphorylation. (A and B) The cell lines shown were treated with PXD101 for up to 72 h. (A) Whole cell extracts were subjected to western blotting with antibodies against total Rb protein or α-tubulin. (B) Total RNA was extracted from cells and used to measure levels of Rb mRNA by RT-qPCR. (C and D) Whole cell extracts from PXD101-treated SUDHL4 (C) or SUDHL8 (D) cells were subjected to western blotting with antibodies against Rb phosphorylated at either Ser780 or Ser795, hypophosphorylated Rb, or α-tubulin. (E and F) Levels of total Rb, pRb Ser780, and pRb Ser795 were quantitated from non-saturated images and normalized to levels of α-tubulin for SUDHL4 (E) and SUDHL8 (F) cells. Normalized values from each timepoint of PXD101 treatment are expressed as fractions or multiples of the normalized value from untreated cells for each individual experiment. All of the results shown are representative of 2–4 independent experiments.