Chemoresistance‑related long non‑coding RNA expression profiles in human breast cancer cells.

Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer death in females worldwide. Chemoresistance has been a major reason for the drug therapy failure. The present study performed a microarray analysis between MCF‑7 and MCF‑7/adriamycin (ADR) cells, and intended to identify long non‑coding (lnc)RNA expression character in drug resistant breast cancer cells. MCF‑7/ADR cells were induced from MCF‑7 cells via pulse‑selection with doxorubicin for 4 weeks, and the resistance to doxorubicin of ADR cells was confirmed by MTT assay. Microarray analysis was performed between MCF‑7 and MCF‑7/ADR cells. Total RNA was extracted from the two cell lines respectively and was transcribed into cDNA. The results of the microarray were verified by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). Gene Ontology (GO) and pathways analysis were conducted to enrich the dysregulated lncRNAs presented in the microarray results. Compared to the MCF‑7 cells, 8,892 lncRNAs were differentially expressed in MCF/ADR cells (absolute fold‑change >2.0). A total of 32 lncRNAs were selected for RT‑qPCR by fold‑change filtering, standard Student's t‑test, and multiple hypothesis testing. Among the dysregulated lncRNAs, AX747207 was prominent because its associated gene RUNX3 was previously reported to be relative to malignant tumor chemoresistance. GO analysis results also indicated some biological processes and molecular functions linked to chemoresistance. The pathway enrichment results provided some potential pathways associated with chemoresistance. In the present study, the authors intended to identify lncRNA expression character in drug resistant cell line MCF‑7/ADR, corresponding to the parental MCF‑7 cell line. In addition, the study identified the lncRNA AX747207, and its potential targeted gene RUNX3, may be related to chemoresistance in breast cancer. These results may new insights into exploring the mechanisms of chemoresistance in breast cancer.