miR-122-5p通过靶向CREB1抑制食管癌细胞及移植瘤的生长

背景与目的:miR-122在多种肿瘤中表达异常,参与肿瘤细胞增殖、凋亡等,而cAMP反应元件结合蛋白1(cAMP response element-binding protein 1,CREB1)参与食管癌发展过程,研究miR-122-5p通过靶向CREB1对食管癌细胞及移植瘤生长的作用及机制.方法:选取2017年11...

miR-122-5p inhibits the growth of esophageal cancer cells and transplanted tumors by targeting CREB1

Background and purpose:?miR-122 is abnormally expressed in various tumors and involved in tumor cell proliferation and apoptosis, while cAMP response element-binding protein 1 (CREB1) is involved in esophageal cancer development. This study aimed to investigate the effect of miR-122-5p on proliferation of esophageal cancer cells and xenografts by targeting CREB1 and its mechanism. Methods: Forty-three specimens of esophageal cancer and corresponding adjacent normal tissues (3-5 cm from the edge of cancer) were collected after tumor resection in Quanzhou First Hospital Affiliated to Fujian Medical University from November 2017 to November 2019. The expressions of miR-122-5p mRNA and CREB1 mRNA in esophageal cancer tissues and cells were detected by real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR). Cells were divided into control group, miR-NC group, pc-NC group, miR-122-5p mimic group, pc-CREB1 group and miR-122-5p mimic+pc-CREB1group. The miR-NC, pc-NC, miR-122-5p mimic and pc-CREB1 plasmids were transfected into EC109 cells separately or jointly using Lipofectamine ^TM 2000. The targeting relationship was verified by the dual-luciferase reporter assay. The cell proliferation was detected by MTT assay. Cell growth ability was tested by cloning formation experiment. The rate of apoptosis was detected by flow cytometry. The Ki-67 labelling index, proliferating cell nuclear antigen (PCNA), activated caspase-3, Bax, Bcl-2 and CREB1 were detected by Western blot. All nude mice were divided into four groups: control group, miR-122-5p mimic group, pc-CREB1 group, miR-122-5p mimic+pc-CREB1 group. Transfected EC109 cells were injected subcutaneously in the left armpit of nude mice. After 30 days, the nude mice were sacrificed, the subcutaneous tumors were completely removed, and the volume and weight of the transplanted tumors were measured. The Ki-67 labelling index and caspase-3 were detected by immunohistochemistry. Results: miR-122-5p was expressed at a low level in esophageal cancer tissues and cells, while CREB1 was highly expressed in esophageal cancer tissues and cells (both P<0.01). miR-122-5p targeted down-regulation of CREB1 was observed. Compared with the control group, the number of esophageal cancer cell clones in the miR-122-5p group decreased, PCNA and Ki-67 labelling index were down- regulated, the apoptotic rate increased, activated caspase-3 and Bax protein expressions were up-regulated, Bcl-2 protein expression was down-regulated, the volume and weight of esophageal cancer EC109 transplanted tumor decreased, the ratio of Ki-67 positive cells increased, and the ratio of caspase-3 positive cells decreased (all P<0.01). Overexpression of CREB1 reversed the effects of miR-122-5p on proliferation and apoptosis of esophageal cancer cells and transplanted tumors. Conclusion: miR-122-5p can inhibit the proliferation of esophageal cancer cells and induce apoptosis by targeted down-regulation of CREB1, thereby inhibiting the growth of esophageal cancer cells and transplanted tumors.