Effects of Ulinastatin on Proliferation and Apoptosis of Breast Cancer Cells by Inhibiting the ERK Signaling Pathway

PURPOSE: To explore the effects of ulinastatin on the proliferation and apoptosis of breast cancer cells and the relevant mechanism of action. METHODS: Breast cancer cells (MCF-7) were cultured and randomly divided into three groups, namely, control group, ulinastatin group, and ulinastatin+extracellular-regulated protein kinase (ERK) inhibitor group. Then, the Cell Counting Kit-8 (CCK-8) assay was carried out to detect the effect of ulinastatin on the viability of breast cancer cells. The effects of ulinastatin on the proliferation and apoptosis of breast cancer cells were determined via EdU staining and Hoechst 33258 staining assays, respectively. The messenger ribonucleic acid (mRNA) and protein expression levels of ERK and forkhead box O3 (FOXO3) in breast cancer cells were measured through reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. RESULTS: In comparison with the control group, the ulinastatin group displayed decreased viability of breast cancer cells, a decreased positive rate of 5-ethynyl-2′-deoxyuridine (EdU) staining, an increased positive rate of Hoechst 33258 staining, and reduced mRNA and protein levels of ERK and FOXO3 in breast cancer cells. Compared with those in the ulinastatin group, the viability of breast cancer cells was lowered, the positive rate of EdU staining was reduced, the positive rate of Hoechst 33258 staining was raised, and the mRNA and protein levels of ERK and FOXO3 in breast cancer cells clearly declined in the ulinastatin+ERK inhibitor group. CONCLUSION: Ulinastatin inhibits the proliferation and promotes the apoptosis of breast cancer cells. The possible mechanism of action is associated with the suppression of the ERK signaling pathway.