Immunofluorescence staining from cells in 12-well plates was performed as previously described35 (link). Primary antibodies used included anti-MCT4 (19-mer peptide sequence CKAEPEKNGEVVHTPETSV-cooh affinity purified rabbit antibody; YenZym Antibodies), anti-GLB1 (ab96239; Abcam), anti-HMGB1 (NB100–2322; Novus Biologicals), and anti-MCT1 (19-mer peptide sequence CSPDQKDTEGGPKEEESPV-cooh affinity purified rabbit antibody; YenZym). Anti-rabbit AlexaFluor 568 (A11036; Invitrogen) secondary antibody was used. Nuclear counterstaining was performed with DAPI. Images were collected with a 40x objective and 1.5 or 2x zoom, when indicated, using a Nikon A1R confocal microscope.