miR-373 inhibits autophagy and further promotes apoptosis of cholangiocarcinoma cells by targeting ULK1.

Intrahepatic cholangiocarcinoma is a malignant tumor originating from intrahepatic bile ducts. Surgical therapy, radiotherapy, and chemotherapy are taken to treat this disease, but it is prone to recurrence and metastasis, with poor prognosis. Therefore, it is of great significance to explore new targets and molecular mechanisms for the development of cholangiocarcinoma cells. Clinical cholangiocarcinoma tissues from patients and four human cholangiocarcinoma cell lines were analyzed for microRNA-373 (miR-373) expression. For investigating whether miR-373 directly modulated unc-51 like autophagy activating kinase 1 (ULK1), dual-luciferase reporter assay was performed. In addition, CCK-8 assay, flow cytometry, western blot, and immunofluorescence were applied to evaluate the proliferation, apoptosis, and autophagy of cholangiocytic hepatocellular carcinoma cells. miR-373 downregulation was observed in clinical tissues and cell lines of cholangiocarcinoma. Overexpression of miR-373 reduced proliferation, enhanced apoptosis, and raised expression levels of pro-apoptosis proteins including BCL2 associated X (Bax), Caspase-3, and Caspase-9. Moreover, overexpression of miR-373 downregulated expression levels of microtubule-associated protein 1A/1B-light chain 3 (LC3)-II, Beclin-1, and promoted P62 expression on mRNA and protein levels. After miR-373 knockdown, all indexes of apoptosis and autophagy mentioned above were reversed. Luciferase activity was decreased after cotransfection of miR-373 mimic and wild-type ULK1 vector. Also, miR-373 overexpression inhibited ULK1 expression. Importantly, overexpression of miR-373 weakened expressions of ULK1, LC3, Beclin-1, and Bcl-2, and enhanced expressions of P62, Bax, Caspase-3, and Caspase-9. miR-373 mimic treatment and subsequent ULK1 overexpression, induced reverse regulation in expressions of these proteins, compared with overexpression of miR-373 only. miR-373 targeted ULK1 to initiate inhibition of autophagy and subsequent promotion of apoptosis in cholangiocarcinoma cells.

Lv P ，Luo YF ，Zhou WY ，Liu B ，Zhou Z ，Shi YZ ，Huang R ，Peng C ，He ZL ，Wang J ，Zhang HH ，Nie SD ... -  《-》

Downregulation of ULK1 by microRNA-372 inhibits the survival of human pancreatic adenocarcinoma cells.

Dysregulation of microRNA (miRNA) expression in various cancers and their role in cancer progression is well documented. The purpose of this study was to investigate the biological role of miR-372 in human pancreatic adenocarcinoma (HPAC). We collected 20 pairs of HPAC tissues and adjacent non-cancerous tissues to detect miR-372 expression levels. We transfected BXPC-3 and PANC-1 cells with miR-372 inhibitor/mimics to study their effect on cell proliferation, apoptosis, invasion, migration and autophagy. In addition, miR-372 mimics and a tumor protein UNC51-like kinase 1 (ULK1) siRNA were co-transfected into BXPC-3 and PANC-1 cells to explore the mechanism of miR-372 and ULK1 on HPAC tumorigenesis. We found that the expression of miR-372 was markedly downregulated in HPAC cells compared to adjacent normal tissues. Furthermore, functional assays showed that miR-372 inhibited cell proliferation, invasion, migration and autophagy in BXPC-3 and PANC-1 cells. An inverse correlation between miR-372 expression and ULK1 expression was observed in HPAC tissues. Downregulation of ULK1 inhibited the overexpression effects of miR-372, and upregulation of ULK1 reversed the effects of overexpressed miR-372. Finally, we found that silencing ULK1 or inhibiting autophagy partly rescued the effects of miR-372 knockdown in HPAC cells, which may explain the influence of miR-372/ULK1 in HPAC development. Taken together, these results revealed a significant role of the miR-372/ULK1 axis in suppressing HPAC cell proliferation, migration, invasion and autophagy.

Chen H ，Zhang Z ，Lu Y ，Song K ，Liu X ，Xia F ，Sun W ... -  《-》

MiR-26 enhances chemosensitivity and promotes apoptosis of hepatocellular carcinoma cells through inhibiting autophagy.

Jin F ，Wang Y ，Li M ，Zhu Y ，Liang H ，Wang C ，Wang F ，Zhang CY ，Zen K ，Li L ... -  《Cell Death & Disease》

Circular RNA circ_0005774 contributes to proliferation and suppresses apoptosis of acute myeloid leukemia cells via circ_0005774/miR-192-5p/ULK1 ceRNA pathway.

Circular RNAs (circRNAs) and microRNAs (miRNAs) have been emerging as new players in acute myeloid leukemia (AML). Hsa_circ_0005774 (circ_0005774) is an upregulated circRNA in pediatric AML, while its role is uncovered. Thus, we intended to measure the function and mechanism of circ_0005774 in AML leukemogenesis. Real time-quantitative PCR revealed that circ_0005774 was highly expressed in blood of pediatric AML patients and AML cells (HL-60 and NB4), accompanied with downregulated miRNA-192-5p (miR-192-5p) which was a crucial tumor-associated and leukemia-related miRNA. Circ_0005774 was abundant in miRNA response element according to CSCD software, and miR-192-5p was identified as a target of circ_0005774, as evidenced by RNA immunoprecipitation and dual-luciferase reporter assays. Cell viability assay, flow cytometry and western blotting were performed to measure cell functions. Accordingly, blocking circ_0005774 and/or overexpressing miR-192-5p could enhance apoptosis rate of HL-60 and NB4 cells, but suppress cell viability and cell cycle entrance, accompanied with depression of proliferation markers including proliferating cell nuclear antigen (PCNA), CyclinD1 and B cell lymphoma 2 (Bcl-2). Meanwhile, depleting miR-192-5p counteracted the role of circ_0005774 knockdown in AML cells. Uncoordinated 51-like kinase 1 (ULK1) was previously demonstrated to be associated with diagnosis, prognosis and therapeutic strategy for AML, and restoring ULK1 could abrogate miR-192-5p overexpression-induced effects in HL-60 and NB4 cells. Notably, ULK1 was a downstream target of miR-192-5p and indirectly modulated by circ_0005774. In conclusion, circ_0005774 knockdown repressed cell proliferation and promoted apoptosis of AML cells partially through regulating miR-192-5p/ULK1 axis.

Li Q ，Luan Q ，Zhu H ，Zhao Y ，Ji J ，Wu F ，Yan J ... -  《-》

MicroRNA-93 Regulates Hypoxia-Induced Autophagy by Targeting ULK1.

Li W ，Yang Y ，Ba Z ，Li S ，Chen H ，Hou X ，Ma L ，He P ，Jiang L ，Li L ，He R ，Zhang L ，Feng D ... -  《-》