RESUMO
@# Objective: To study the miR-28-3p expression in triple negative breast cancer (TNBC) tissues and cell lines, and explore its effect on the malignant biological behaviors of MDA-MB-468 cells. Methods： ：Tumor tissues and matched para-cancerous tissues were collected from 83 TNBC patients, who underwent tumor resection and pathological confirmation in the Fourth Hospital of Hebei Medical University between Jan. 2013 and Jan. 2014. TNBC cell lines (MDA-MB-468, HCC-1937, MDA-MB-231, MDA-MB436, MDA-MB-453) and human normal breast epithelial cell line MCF10A were also used in this study. qPCR was used to detect the expression of miR-28-3p in above mentioned tissues and cell lines. The correlation between miR-28-3p expression and clinical parameters was analyzed.After transfection with miR-28-3p inhibitor, the proliferation, apoptosis, invasion and migration ability of MDA-MB468 cells were detected with CCK-8, Flow cytometry, Transwell and Wound-healing experiment, respectively. And Western blotting was used to examine the protein expression of bridging integrator-1 (BIN1) in MDA-MB-468 cells. Bioinformatics BIN1 tool waere used to predict the target gene of miR-28-3p. Luciferase reporter gene assay was performed to validate the regulatory effect of miR-28-3p on BIN1. Results: The expression of miR-28-3p in TNBC tissues and cell lines was higher than that in matched paracancerous tissues and MCF10Acells (all P<0.01), respectively.Among the total 83 TNBC tissues, 56 (67.47%) showed high miR-28-3p expression. High expressionofmiR-28-3pwascloselycorrelated with the Ki-67 expression, tumor size and TNM stage (all P<0.05 or P<0.01). Compared with miR-NC group, transfection of miR-28-3p inhibitor significantly decreased the proliferation, invasion and migration of MDA-MB-468 cells while increased the apoptosis rate (all P<0.05 or P<0.01). Luciferase reporter gene assay confirmed that BIN1 was a target gene of miR-28-3p, and miR-28-3p inhibitor could up-regulate BIN1 expression in MDA-MB-468 cells (P<0.05). Conclusion: miR-28-3p is highly expressed in TNBC tissues and cell lines. miR-28-3p inhibitor up-regulates the expression of BIN1 to inhibit the proliferation, invasion and migration ability while promote the apoptosis of MDA-MB-468 cells.
RESUMO
@# Objective：To investigate the role and mechanism of chromosomal region maintenance 1 (CRM1) inhibitor sulforaphene (LFS-01) in killing triple negative breast cancer (TNBC) cells by inhibiting signal transducer and activator of transcription 3 (STAT3) signaling pathways. Methods: Whether LFS-01 could combine with the NES pocket of CRM1 was verified by molecular dynamics simulation techniques. The killing activity of LFS-01 on four different breast cancer cell lines was detected by CCK-8 method. TNBC MDA-MB-468 and MDA-MB-231 cells were treated with different concentrations of LFS-01, and the intracellular localization of CRM1 cargo protein STAT3 and protein with NES sequence was detected by immunofluorescence; WB was used to detect the effect of LFS-01 on the expression of STAT-3 signaling pathway and its downstream proteins; WB, cellular immunofluorescence and transmission electron microscopy were adopted to detect the occurrence of autophagy; the effect of LFS-01 on cell cycle and apoptosis was detected by flow cytometry. Results: Molecular dynamics simulations showed that LFS-01 can bind to the NES pocket of CRM1, indicating that it may structurally affect the latter's protein transport function. LFS-01 could specifically kill TNBC MDA-MB-468 and MDA-MB-231 cells. STAT3 and NES-tagged proteins were mainly blocked in the nucleus of TNBC cells after the treatment with 10 μmol/L LFS-01, while they were evenly distributed in the cytoplasm in the control group. The expressions of phosphorylated STAT3 protein, Bcl-xL and Cylin D1 were decreased in MDA-MB-468 and MDA-MB-231 cells with the increase of LFS-01 dose and the prolongation of treatment time; the expression of autophagy marker protein LC3B increased, and highdensity, multi-layered autophagosomes appeared at the same time; cell cycle arrest was observed in S phase and apoptosis rate was significantly increased (P<0.05 or P<0.01). Conclusion: LFS-01 blocks the export of CRM1 carrier protein, thereby inhibiting the activation of STAT3 signaling pathway and promoting autophagy, cell cycle arrest and apoptosis in TNBC MDA-MB-468 and MDAMB-231 cells.
RESUMO
@# Objective: To explore the effect of miR-424/HMGA1 (high mobility proteinA1) axis on the radio-sensitivity of breast cancer cells and the possible mechanism. Methods:Atotal of 50 cases of breast cancer tissues from patients, who underwent surgical resection at the Department of Oncological Radiotherapy, Wuxi Fourth People’s Hospital from April 2014 to April 2017, were collected for this study. Real-time quantitative polymerase chain reaction (qPCR) and Western blotting were performed to evaluate the mRNA and protein expressions of miR-424 and HMGA1 in breast cancer tissues of radiation sensitive and insensitive patients. After being treated with different doses of 60Co γ-ray radiation (0, 2, 4, 6 and 8 Gy), the expression changes of miR-424 and HMGA1 in breast cancer MDA-MB-468 cells were observed. Subsequently, miR-424 mimic/inhibitor and pcDNA-HMGA1 were transfected into MDA-MB-468 cells, and the effect of miR-424 on cell proliferation, invasion and apoptosis of radiation-treated MDA-MB-468 cells were evaluated by colony formation assay, MTT assay, Transwell assay and Annexin V-FITC/PI double staining flow cytometry assay, respectively. Furthermore, dual luciferase reporter gene assay was used to verify whether HMGA1 was a target gene of miR-424. Results: The patients in radio-sensitive group exhibited higher miR-424 expression but lower HMGA1 expression than the patients in insensitive group (all P<0.01). Compared with the cells treated with 0, 2 and 4 Gy radiation, the cells treated with 6 and 8Gy radiation exhibited significantly higher apoptosis rate and miR-424 expression but lower HMGA1 expression and cell invasion (all P<0.01). Moreover, luciferase reporter gene assay confirmed that miR-424 down-regulated HMGA1 expression. Mechanistically, miR-424 significantly inhibited cell proliferation, invasion and induced apoptosis of MDA-MB-468 cells (all P<0.01) via targeted down-regulating HMGA1, and further upregulated the radio-sensitivity of breast cancer cells. Conclusion: miR-424/HMGA1 axis regulates the radio-sensitivity of breast cancer, and over-expression of miR-424 may increase the sensitivity of MDA-MB-468 cells to γ-ray radiation therapy.