MiR-1271 negatively regulates AKT/MTOR signaling and promotes apoptosis via targeting PDK1 in pancreatic cancer

F. Xie, Q. Huang, C.-H. Liu, X.-S. Lin, Z. Liu, L.-L. Liu, D.-W. Huang, H.-C. Zhou

Department of General Surgery, Shandong University School of Medicine, Jinan, China. huangqiang0901@sina.com

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• Oncology

OBJECTIVE: Pancreatic cancer (PC) possesses a very poor prognosis, and its pathogenesis is not fully understood. Evidence has suggested that microRNAs play important roles in cancer development and progression, the present study was designed to study the function of miR-1271 in PC.

PATIENTS AND METHODS: PC tissues and adjacent normal tissues were collected from 17 patients. MiR-1271 and PDK1 expression were quantified by quantitative reverse-transcriptional polymerase chain reaction (RT-PCR). AKT/MTOR signaling activity and PDK1 protein expression were determined by Western blot. Cell viability and apoptosis were assessed by MTT assay and enzyme-linked immunosorbent assay (ELISA). Luciferase assay was used to verify whether miR-1271 directly targets PDK1.

RESULTS: MiR-1271 was significantly down-regulated in PC tissues compared with that in the paired normal adjacent tissue, and its expression was up-regulated dose-dependently upon cisplatin treatment in PC cells. Overexpression of miR-1271 in these cells produced a pro-apoptotic effect, similar to what caused by cisplatin treatment. Moreover, overexpression of miR-1271 inhibited AKT/MTOR signaling, which was due to the targeting relationship between miR-1271 and PDK1. Finally, knockdown of PDK1 exerted a similar effect on apoptosis to that of miR-1271 overexpression.

CONCLUSIONS: MiR-1271 is a potent tumor suppressor in PC, its pro-apoptotic function was partially mediated by reduced AKT/MTOR signaling. Targeting miR-1271 may represent an effective strategy for PC treatment.

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