miR-424 modulates radio-sensitivity of breast cancer cells via targeting HMGA1 / 中国肿瘤生物治疗杂志

ABSTRACT

@# 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.