No abstract

Background: Lung cancer remains the most frequent malignancy worldwide with increasing morbidity and mortality. This study aimed to assess the expression of microRNA-374b-5p (miR-374b-5p) in tissues and cell lines of non-small cell lung cancer (NSCLC) and to evaluate the prognostic value of miR-374b-5p as well as its biological function in tumor progression. Materials and Methods: Expression of miR-374b-5p in NSCLC patients and cells was estimated using quantitative real-time PCR. The prognostic value of miR-374b-5p was evaluated using Kaplan-Meier method and Cox regression analysis. Gain-of-function and loss-of-function cell experiments were performed to examine the effects of miR-374b-5p on NSCLC cell proliferation, migration and invasion. A luciferase activity assay was used to confirm the target gene of miR-374b-5p. Results: miR-374b-5p expression levels were decreased in tumorous tissues and cell lines compared with the normal tissues or cells (P < 0.05). The expression of miR-374b-5p was associated with the patients' tumor size, lymph node metastasis and TNM stage (all P < 0.05). Patients with low miR-374b-5p expression have a shorter survival time (log-rank P = 0.001), and the downregulated expression of miR-374b-5p was determined to be an independent prognostic indicator of NSCLC. In NSCLC cells, the overexpression of miR-374b-5p could inhibit NSCLC cell proliferation, migration and invasion and could directly target FOXP1. Conclusion: This study found that the decreased miR-374b-5p predicts poor prognosis of NSCLC, and the upregulation of miR-374b-5p can inhibit NSCLC cell proliferation, migration and invasion. The data obtained from this study provide a novel candidate prognostic biomarker and a potential therapeutic target for NSCLC.

Gastric cancer (GC) is one of the most common malignancies with a high worldwide incidence rate. The association between microRNAs (miRs) and malignancy has been widely studied in recent years. The aim of the present study was to assess the clinical value of miR-4636 in patients with GC and its effect on the proliferation, migration and invasion of GC cells. Reverse transcription-quantitative PCR was used to detect the expression of miR-4636. Receiver operating characteristics curve, Kaplan-Meier survival curve and Cox regression analyses were used to evaluate the diagnostic and prognostic value of miR-4636. Transwell migration and MTT assays were used to assess the regulatory effects of miR-4636 expression on the biological function of GC. The results demonstrated that the expression of miR-4636 was significantly downregulated in GC serum and tissue samples, as well as in GC cell lines. The aberrant miR-4636 expression was closely associated with lymph node metastasis and TNM stage, and had considerable diagnostic and prognostic significance in patients with GC. Cellular experiments revealed that the overexpression of miR-4636 inhibited GC cell proliferation, migration and invasion, while the knockdown of miR-4636 led to opposite effects on the biological function of GC. In summary, decreased miR-4636 expression may serve as a biomarker for the diagnosis and prognosis of GC. Furthermore, miR-4636 overexpression significantly inhibited GC cell proliferation, migration and invasion, indicating the potential of miR-4636 as a therapeutic target for GC treatment.

Several microRNAs (miRNA/miR) have been reported to serve critical roles in tumorigenesis. The present study aimed to investigate miR-518b expression in non-small cell lung cancer (NSCLC), and determine its clinical significance and biological function in this malignancy. Reverse transcription-quantitative PCR was performed to assess miR-518b expression in NSCLC. The diagnostic value of miR-518b was determined via a receiver operating characteristic curve, while its prognostic value was assessed using the Kaplan-Meier method. Gain-and loss-of-function experiments were performed to determine the functional role of miR-518b in NSCLC progression. The results demonstrated that miR-518b expression was upregulated in NSCLC serum, tissues and cell lines compared with the corresponding normal controls. Furthermore, high miR-518b expression was significantly associated with larger tumor size, lymph node metastasis and advanced TNM stage, as well as poor overall survival in patients with NSCLC. Serum miR-518b expression was identified as a candidate diagnostic biomarker for NSCLC, with sensitivity of 88.1% and specificity of 81.7%. Furthermore, the cell experiments indicated that NSCLC cell proliferation, migration and invasion were enhanced following overexpression of miR-518b; however, these effects were reversed following miR-518b knockdown. Taken together, the results of the present study suggest that elevated miR-518b expression in NSCLC serves a potential oncogenic role by facilitating tumor cell proliferation, migration and invasion, and thus may serve as a candidate diagnostic and prognostic biomarker.

Non-small cell lung cancer (NSCLC) is a common malignant tumor with poor prognosis and an increasing number of cases. MicroRNA (miR)-4728 is related with the progression of various types of cancer, and is dysregulated in NSCLC, which indicates that miR-4728 may serve as a biomarker for NSCLC. The present study aimed to investigate the clinical significance of miR-4728 in NSCLC diagnosis and prognosis, and to explore the biological function of miR-4728 in NSCLC progression. Serum and tissue samples were collected from 122 patients with NSCLC. By conducting reverse transcription-quantitative PCR, the Cell Counting Kit-8 assay and Transwell assays, the expression of miR-4728 and its effect on NSCLC cell proliferation, migration and invasion were investigated. The diagnostic value of miR-4728 was evaluated by plotting a receiver operating characteristic curve, and Kaplan-Meier and Cox regression analyses were conducted to assess the prognostic value of miR-4728. miR-4728 was significantly downregulated in NSCLC serum and tissue samples compared with healthy controls, with a relatively high diagnostic accuracy and ability to predict poor overall survival time in patients with NSCLC. By conducting gain-and loss-of-function experiments, the results indicated that miR-4728 knockdown significantly promoted NSCLC cell proliferation, migration and invasion compared with the inhibitor negative control (NC) group. By contrast, miR-4728 overexpression displayed the opposite effect on NSCLC cell proliferation, migration and invasion. The present study indicated that miR-4728 was downregulated in NSCLC and may serve as a candidate diagnostic and prognostic biomarker. NSCLC cell proliferation, migration and invasion were inhibited by miR-4728 overexpression compared with the mimic NC group, which suggested that miR-4728 may serve as a therapeutic target for NSCLC.