TY - JOUR AB - Long non‑coding RNAs (lncRNAs) have attracted widespread attention as potential biological and pathological regulators. lncRNAs are involved in several biological processes in cancer. Triple negative breast cancer (TNBC) is characterized by strong heterogeneity and aggressiveness. At present, the implication of microRNAs (miRs) and lncRNAs in immunotherapy has been poorly studied. Nevertheless, the blockade of immune checkpoints, particularly that of the programmed cell‑death protein‑1/programmed cell‑death ligand‑1 (PD‑L1) axis, is considered as a principle approach in breast cancer (BC) therapy. The present study aimed to investigate the interaction between immune‑modulatory upstream signaling pathways of the PD‑L1 transcript that could enhance personalized targeted therapy. MDA‑MB‑231 cells were transfected with miR‑182‑5p mimics followed by RNA extraction and cDNA synthesis using a reverse transcription kit, and the expression levels of the target genes were assessed by reverse transcription‑quantitative PCR. Furthermore, the expression levels of target genes were measured in tissues derived from 41 patients with BC, including patients with luminal BC and TNBC, as well as their adjacent lymph nodes. The results revealed that the expression levels of miR‑182‑5p, PD‑L1 and metastasis‑associated lung adenocarcinoma transcript 1 (MALAT1) were upregulated in MDA‑MB‑231 cells and BC tissues. However, X‑inactive specific transcript (XIST) expression was downregulated in cancer tissues and TNBC cells. Following co‑transfection of cells with small interfering RNAs specific for each target gene and miR‑182‑5p antagomirs, the effect of miR‑182‑5p was abolished in the presence of lncRNAs. Therefore, the results of the present study indicated that although miR‑182‑5p exhibited an oncogenic effect, XIST exerted a dominant effect on the regulation of the PD‑L1 signaling pathway via the inhibition of the oncogenic function of MALAT1. AD - Molecular Pharmacology Research Group, Department of Pharmacology and Toxicology, German University in Cairo, Cairo 11835, Egypt Department of General Surgery, Ain Shams University, Cairo 11772, Egypt AU - Samir,Amany AU - Tawab,Reda,Abdel AU - El Tayebi,Hend,M. DA - 2021/08/01 DO - 10.3892/ol.2021.12854 IS - 2 JO - Oncol Lett KW - triple negative breast cancer immunotherapy long non‑coding RNAs programmed cell‑death ligand‑1 metastasis‑associated lung adenocarcinoma transcript 1 X‑inactive specific transcript PY - 2021 SN - 1792-1074 1792-1082 SP - 593 ST - Long non‑coding RNAs XIST and MALAT1 hijack the PD‑L1 regulatory signaling pathway in breast cancer subtypes T2 - Oncology Letters TI - Long non‑coding RNAs XIST and MALAT1 hijack the PD‑L1 regulatory signaling pathway in breast cancer subtypes UR - https://doi.org/10.3892/ol.2021.12854 VL - 22 ER -