PD-L1 ChIP-seq in MDA-MB-231 cells

Although membrane-anchored PD-L1 has been well-studied for its engagement with PD-1 on T cells to evade anti-tumor immunity, whether PD-L1 regulate oncogenic signaling pathways in tumor cells remains elusive. We found that a portion of PD-L1 could translocate to the nucleus and knockout of PD-L1 changed RNA profiles in MDA-MB-231 cells. To further explore potential role of PD-L1 in regulating gene expression in tumor cells, we performed ChIP-seq in HA tag-inserted (after the signal peptide) PD-L1 re-expressed MBA-MB-231cells (endogenous PD-L1 knockout background). Methods: HA-insert-PD-L1 was re-introduced into MDA-MB-231 PD-L1 knockout cells using lentivirus and then the infected cells were selected with puromycin to make stable subclones. ChIP experiments were performed using HA antibody (Abcam, ab9110). Conclusions: Our study indicates that nuclear PD-L1 has potential roles in regulating gene transcription. More efforts are needed to further dissect the exact working model. ChIP experiments were performed in two independent biological replicates using HA antibody (Abcam, ab9110). Sequecing data were respectively called for enriched peaks.