Construction and analysis of competing endogenous RNA network of MCF‑7 breast cancer cells based on the inhibitory effect of 6‑thioguanine on cell proliferation

Previous research has proven that 6‑thioguanine (6‑TG) inhibits the growth of MCF‑7 breast cancer cells. Accumulating evidence indicates that long non‑coding (lnc)RNAs are involved in the development of various cancer types as competitive endogenous (ce)RNA molecules. The present study was conducted to investigate the regulatory mechanism underlying the function of lncRNAs as ceRNA molecules in MCF‑7 cells and to identify more effective prognostic biomarkers for breast cancer treatment. The expression profiles of lncRNAs in untreated MCF‑7 cells and 6‑TG‑treated MCF‑7 cells were compared by RNA‑seq. The regulatory associations among lncRNAs, micro (mi)RNAs and mRNAs were analyzed and verified by the TargetScan, miRDB and miRTarBas databases. The ceRNA networks were constructed by Cytoscape. The expression levels of two lncRNAs and two miRNAs in the ceRNA network were measured by reverse transcription‑quantitative PCR. The OncoLnc and Kaplan‑Meier plotter network databases were utilized to determine the effects of lncRNA and miRNA expression on the survival of patients with breast cancer. A ceRNA network was constructed for MCF‑7 breast cancer cells treated with 6‑TG, and this network may provide valuable information for further research elucidating the molecular mechanism underlying the effects of 6‑TG on breast cancer. Moreover, LINC00324, MIR22HG, miR‑370‑3p and miR‑424‑5p were identified as potential prognostic and therapeutic biomarkers for breast cancer.