Foxa1 antibody

Immunohistochemistry was performed on paraformaldehyde-fixed paraffin sections. Paraffin embedded samples were cut into 4 μm-thick sections, which were baked at 60 °C for at least 6 hours. Paraffin sections were then deparaffinized in xylene and re-hydrated through graded ethanol. Antigen retrieval was performed in sodium citrate buffer for 2 minutes in a pressure cooker, and then these slices were quenched for endogenous peroxidase activity in 3% hydrogen peroxide for 10 min. They were blocked with goat plasma at 37 °C for 30 minutes and incubated with FOXA1 antibody (1:100, #5089, Abcam, Cambridge, MA) or Ki-67 antibody (1:100, #9027, Cell Signaling, Danvers, MA, USA) at 4 °C overnight. The biotinylated secondary antibody (ZSGB-Bio, Beijing, China) was used to detect the primary antibody. Then sections were incubated with diaminobenzidine before being counterstained with hematoxylin. At last, they were dehydrated in graded ethanol and transparentized in xylene. The percentage of positive tumor cells or hepatocytes was graded as per the following criteria: 0, less than10%; 1, 10–30%; 2, 31–50%; 3, more than 50%.

Chromatin immunoprecipitation (ChIP) was performed as described previously 35 (link). Cells were fixed with 1% formaldehyde, and nuclei were extracted. Chromatin/DNA complex was sheared in a sonicator. Sonicated lysates were cleared and incubated overnight at 4°C with magnetic beads coupled with one of the following antibodies: H3K27ac antibody (Abcam, ab4729), FOXA1 antibody (Abcam, ab23738), YBX1 antibody (Abcam, ab76149) or ERα antibody (Santa Cruz, sc-543). DNA was eluted and analyzed by qPCR. The ChIP-qPCR primers are listed in Table S1.