[Expression of nucleolar protein 14 and CD31 in pancreatic cancer mouse model and its correlation with tumor progression]

Subcellular localization of nucleolar protein 14 and its proliferative function mediated by miR-17-5p and E2F4 in pancreatic cancer

Pancreatic cancer is one of the most lethal malignancies worldwide. Acquiring infinite proliferation ability is a key hallmark and basis of tumorigenesis. NOP14 is an identified ribosome biogenesis protein that plays potential roles in cell proliferation. However, the function and molecular mechanism of NOP14 remain ambiguous in most human cancers. In this study, we first investigated the subcellular localization and expression of NOP14 by multiple quantitative assays in pancreatic cancer. We confirmed that NOP14 was mainly localized in nucleolus in human pancreatic cancer cells. Then we studied the regulatory effects of this nucleolus protein on tumor cell proliferation in vitro. NOP14 was demonstrated to play a dominant pro-proliferation role in pancreatic cancer. Furthermore, we identified miR17-5p as a downstream target of NOP14. Transfection of miR17-5p mimics or inhibitors rescued the down- or upregulated effect of NOP14 on cell proliferation by regulating expression of P130. In addition, NOP14 induced expression of transcription factor E2F4 independent of miR17-5p/P130 signaling, which simultaneously activated a set of targeted genes, such as CCNE1, PIM1, AKT1 etc., to promote tumor proliferation. These findings might provide novel insights for better understanding the diverse function of NOP14 in human malignancies to develop new strategies for targeted therapy.

A New RBPs-Related Signature Predicts the Prognosis of Colon Adenocarcinoma Patients

The dysregulation of RNA binding proteins (RBPs) is closely related to tumorigenesis and development. However, the role of RBPs in Colon adenocarcinoma (COAD) is still poorly understood. We downloaded COAD’s RNASeq data from the Cancer Genome Atlas (TCGA) database, screened the differently expressed RBPs in normal tissues and tumor, and constructed a protein interaction network. COAD patients were randomly divided into a training set (N = 315) and a testing set (N = 132). In the training set, univariate Cox analysis identified 12 RBPs significantly related to the prognosis of COAD. By multivariate COX analysis, we constructed a prognostic model composed of five RBPs (CELF4, LRRFIP2, NOP14, PPARGC1A, ZNF385A) based on the lowest Akaike information criterion. Each COAD patient was scored according to the model formula. Further analysis showed that compared with the low-risk group, the overall survival rate (OS) of patients in the high-risk group was significantly lower. The area under the curve of the time-dependent receiver operator characteristic (ROC) curve was 0.722 in the training group and 0.738 in the test group, which confirmed a good prediction feature. In addition, a nomogram was constructed based on clinicopathological characteristics and risk scores. C-index and calibration curve proved the accuracy in predicting the 1-, 3-, and 5-year survival rates of COAD patients. In short, we constructed a superior prognostic and diagnostic signature composed of five RBPs, which indicates new possibilities for individualized treatment of COAD patients.

[miR-122-5p inhibits the proliferation of melanoma cells by targeting NOP14]

OBJECTIVE

To investigate the expression profile of miR-122-5p in melanoma tissues and the effect of miR-122-5p on the proliferation, cell cycle and apoptosis of human melanoma cell lines SK-MEL-110 and A375.

METHODS

The expression profiles of miR-122-5p in melanoma and pigmented nevus tissues were detected using real-time fluorescence quantitative PCR (qRT-PCR). SK-MEL-110 and A375 cells transfected with miR-122-5p inhibitor or negative control inhibitor (NC) I were examined for miR-122- 5p expression using qRT-PCR and changes in cell proliferation, cell cycle and apoptosis using MTT assay or flow cytometry. NOP14 mRNA and protein expressions in the cells were detected using qRT- PCR and Western blotting, respectively. Luciferase reporter assay was used to confirm the identity of NOP14 as the direct target of miR-122-5p.

RESULTS

The relative expression of miR-122-5p in human pigmented nevus tissues and melanoma tissues was 1.23±0.270 and 7.65 ± 1.37, respectively. The relative expression of miR-122-5p in SK-MEL-110 and A375 cells transfected with miR-122-5p inhibitor was 0.21 ± 0.08 and 0.17 ± 0.05, respectively. miR-122-5p inhibitor obviously inhibited the cell proliferation and increased the percentage of cells in G1 stage in both SK-MEL-110 and A-375 cells, but did not cause obvious changes in the apoptosis of the two cells. miR-122-5p inhibitor did not significantly affect the expression level of NOP14 mRNA, but obviously increased the expression level of NOP14 protein. Luciferase reporter assay revealed a significantly lower luciferase activity in cells co-transfected with miR-122-5p mimics and wild-type psi-CHECK2-3'UTR plasmid than in the cells cotransfected with NC and wild-type psi-CHECK2-3'UTR plasmid (0.21 ± 0.14 vs 0.56 ± 0.1, P < 0.01).

CONCLUSIONS

miR-122-5p expression is upregulated in melanoma tissues, indicating its involvement in the development of melanoma. miR-122-5p inhibits the proliferation of SK-MEL-110 and A-375 cells possibly by affecting the cycle through NOP14.