Suppression of miR-30a/HMGA2-mediated autophagy in osteosarcoma cells impacts chemotherapeutics-induced apoptosis.

Qin Xia; Jiangdong NI; Jun Huang; Baiqi Pan; Mingming Yan; Wenzhao LI

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Suppression of miR-30a/HMGA2-mediated autophagy in osteosarcoma cells impacts chemotherapeutics-induced apoptosis.

Author: Qin XIA ¹ ; Jiangdong NI ¹ ; Jun HUANG ¹ ; Baiqi PAN ¹ ; Mingming YAN ¹ ; Wenzhao LI ¹
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1. Department of Orthopedics, Second Xiangya Hospital, Central South University, Changsha 410011, China.
Publication Type:Journal Article
MeSH: Apoptosis; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Bone Neoplasms; Cell Line, Tumor; HMGA2 Protein; metabolism; Humans; MicroRNAs; genetics; Osteosarcoma
From: Journal of Central South University(Medical Sciences) 2019;44(7):757-766
CountryChina
Language:Chinese
Abstract: To investigate the effect of miR-30a/HMGA2-mediated autophagy in osteosarcoma cells on apoptosis induced by chemotherapeutics.   Methods: A total of 30 osteosarcoma tissues of sensitive and resistant to chemotherapeutics were divided into a chemotherapy-sensitive group and a chemotherapy-resistant group. The mRNA expression levels of miR-30a and high mobility group protein A2 (HMGA2) in the chemotherapy-sensitive group and the chemotherapy-resistant group, and the mRNA expression levels of miR-30a in osteosarcoma U2-OS cells treated by cisplatin, doxorubicin and methotrexate at different concentrations were detected by real-time PCR. The expression levels of autophagy related protein Beclin 1, microtubule associated protein 1 light chain 3B (LC3B) and autophagy factor P62 were detected by Western blotting. The osteosarcoma U2-OS cells were transfected with miR-30a mimics and miR-30a inhibitors to construct a miR-30a high expression group, a miR-30a low expression group and a control group. The expression levels of Beclin 1, LC3B and P62 in osteosarcoma U2-OS cells after treatment of cisplatin and doxorubicin in these 3 groups were detected by Western blotting; the level of autophagy was detected by monodansylcada (MDC) staining; the level of ROS was detected by dihydroethidium (DHE); the level of cell surviving rate was detected by cell counting kit-8 (CCK-8); the level of apoptosis was detected by annexin APC/PI double staining; the level of mitochondria oxidative damage was detected by mitochondrial membrane potential assay kit with JC-1 (JC-1 method). The interaction between miR-30a and HMGA2 was detected by dual luciferase reporter assay. The osteosarcoma U2-OS cells were transfected with HMGA2 mimics and HMGA2-shRNA to construct a high HMGA2 group, a low HMGA2 group, and a control group. The expression levels of Beclin 1, LC3B and P62 in osteosarcoma U2-OS cells after the treatment of cisplatin were detected by Western blotting.  Results: The level of miR-30a in the chemotherapy-resistant tissues was significantly lower than that in the chemotherapy-sensitive tissues (P<0.05), and the expression of HMGA2 was opposite comparing to that of miR-30a (P<0.05). After the treatment by low concentration (5 μmol/L) of chemotherapeutics, the level of miR-30a was down-regulated in osteosarcoma U2-OS cells, accompanied with up-regulation of Beclin 1 and LC3B (P<0.01) and down-regulation of P62 (P<0.01). Compared with the control group, the expression levels of Beclin 1 and LC3B were significantly decreased (P<0.05), and the expression level of P62 was significantly increased (P<0.05) in the miR-30a high expression group, which was opposite in the miR-30a low expression group. In the miR-30a high expression group treated by chemotherapeutics, the level of autophagy and the cell survival rate were lower than those in group with low expression of miR-30a, while the levels of ROS, the mitochondrial oxidative damage and the apoptosis were higher than those in group with low expression of miR-30a (all P<0.05). The targeting interaction between HMGA2 and miR-30a were verified by dual luciferase reporter assay. Compared with the control group, the expression levels of Beclin 1 and LC3B were significantly increased (P<0.05), and the expression level of P62 was significantly decreased (P<0.05) in the HMGA2 high expression group, which was opposite in the HMGA2 low expression group.  Conclusion: Suppression of miR-30a/HMGA2-mediated autophagy in osteosarcoma cells is likely to enhance the therapeutic effect of chemotherapeutics.