MicroRNA as a new factor in lung and esophageal cancer

miR-325 Supresses Cell Proliferation and Migration in Non-Small Cell Lung Cancer via Targeting DNA Ligase 1 (LIG1)

DNA ligase 1 (LIG1) plays a key role in DNA synthesis and DNA damage repair pathways. LIG1 has been shown to be up-regulated in human non-small cell lung cancer (NSCLC); however, its role and molecular regulatory mechanism in NSCLC cell proliferation are still not fully understand. In this study, we aimed to explore the role of LIG1 and post-transcripional regulators in NSCLC. Utilizing bioinformatic tools and qRT-PCR, our investigation substantiated the up-regulation of LIG1 within NSCLC cell lines and tumour tissues. Remarkably, individuals exhibiting elevated levels of LIG1 had diminished survival rates. Functionally, the depletion of LIG1 inhibited cell proliferation and migration, contrasting with the increased proliferation and migration upon LIG1 over-expression. Prediction from the TargetScanHuman database and results of dual luciferase reporter assays indicated that miR-325 could directly bind to and negatively regulate LIG1. Moreover, our findings demonstrated that the mimicry of miR-325 decreased cell viability, whereas its inhibition correspondingly increased viability, indicative of the tumour-suppressive role of miR-325 through the down-regulation of LIG1. Collectively, our findings show that LIG1 could promote tumour progression and knockdown of LIG1 could exert suppressive effects on NSCLC. As the post-transcriptional factor of LIG1, miR-325 could negatively regulate the expression of LIG1 to inhibit tumour progression in vitro. These findings suggest that LIG1 and miR-325 might be potential therapeutic targets for NSCLC treatment.

Epidermal growth factor as a potential prognostic and predictive biomarker of response to platinum-based chemotherapy

In this study, we investigated serum epidermal growth factor (EGF) in an oncological population of head- and neck and pulmonary neoplasms and whether serum EGF could serve as a prognostic marker of survival and as a predictive marker for treatment response to platinum-based chemotherapy. A total of 59 oncological patients and a control group of age- and sex-matched healthy volunteers were included in this study. Pre-treatment serum EGF from both groups was determined. Patient’s and tumour characteristics and mortality were recorded during a 5-year follow up period. Baseline serum EGF significantly differed between the oncological patients and the healthy volunteers (p<0.001). Serum EGF was associated with lymph node metastasis (p = 0.004) but not with sex (p = 0.753), age (p = 1.00), TNM stage (p = 0.191) or tumour size (p = 0.077). Neither serum EGF (p = 0.81) nor age (p = 0.55) showed an effect on the patient’s survival. Tumour location was significantly associated with overall 5-year survival (p = 0.003). The predictive capacity of serum EGF of response to chemotherapy was limited (AUC = 0.606), a sensitivity of 80% and a specificity of 56% was observed resulting in a likelihood ratio of a positive and negative test equal to 1.81 and 0.36, respectively. In conclusion, serum EGF levels are 5.5 times higher in an oncological population compared to a control group. Within the oncological population, low serum EGF values are associated with the presence of lymph node metastasis. Further investigation is necessary to determine if the serum EGF levels could serve as a diagnostic biomarker.

Downregulated microRNA-140-5p expression regulates apoptosis, migration and invasion of lung cancer cells by targeting zinc finger protein 800

Despite advances in the diagnosis and treatment in recent years, lung cancer is still one of the primary causes of cancer-associated morbidity and mortality in globally. Abnormally expressed microRNAs (miRNAs/miRs) in tumor tissues serve vital roles in the pathological mechanism of tumors and have become prospective biomarkers for cancer diagnosis. The present study aimed to investigate the effects of the miR-140-5p/zinc finger protein 800 (ZNF800) axis in lung carcinoma, and determine its potential underlying molecular mechanisms. The degree of cell proliferation was assessed via the MTT assay, while the migratory and invasive abilities of lung cancer cells were determined via the Transwell and Matrigel assays. The expression levels of miR-140-5p and ZNF800 were detected via reverse transcription-quantitative PCR and western blot analyses. The results demonstrated that miR-140-5p expression was notably higher in normal human bronchial epithelial cells compared with the respective lung cancer cell lines, H292, PC-9, CL1-5 and H460. Furthermore, miR-140-5p expression increased in the lung cancer cells compared with the control cells following transfection with miR-140-5p mimic. Overexpressing miR-140-5p significantly suppressed the proliferative, invasive and migratory abilities of H460 and PC-9 cells, and stimulated cell apoptosis by upregulating the expression of cleaved-caspase-3. Notably, these effects were reversed following transfection with miR-140-5p inhibitor. miR-140-5p was predicted as a negative regulator of ZNF800, and ZNF800 knockdown significantly suppressed the proliferative and metastatic abilities of lung adenocarcinoma (LUAD) cells, which was comparable to the effects of miR-140-5p mimic. Taken together, these results suggest that miR-140-5p may block the malignant phenotype of LUAD by negatively regulating ZNF800 expression. Thus, the miR-140-5p/ZNF800 axis may be used as an alternative therapeutic target for lung carcinoma in general, and LUAD in particular.

miR-433 reduces cell viability and promotes cell apoptosis by regulating MACC1 in colorectal cancer

MicroRNAs (miRNAs) are reported to have important roles in regulating the progression of numerous human cancers, although little is known regarding the role of miRNAs in colorectal cancer. The present study aimed to investigate the role of microRNA-433 (miR-433) in colorectal cancer. The expression levels of miR-433 and its target gene metastasis associated in colon cancer-1 (MACC1) in colorectal cancer tissues were evaluated using reverse transcription-quantitative polymerase chain reaction and western blotting. Furthermore, flow cytometry and MTT assays were used to examine the apoptosis, cell cycle distribution and viability of human colorectal cancer cells, and luciferase reporter and western blot assays were performed to verify the regulatory mechanism of miR-433 on MACC1. In addition, caspase-3 and caspase-9 expression were examined using western blotting. It was demonstrated that miR-433 expression was downregulated in colorectal cancer tissues and cell lines. Artificial upregulation of miR-433 in colorectal cancer cell lines using miR-433 mimics revealed that upregulation of miR-433 was able to reduce the viability and promote the apoptosis of colorectal cancer cells by downregulating MACC1. Taken together, these results suggested that miR-433 may have an important role in the pathogenesis of colorectal cancer.

miR-362-3p targets nemo-like kinase and functions as a tumor suppressor in renal cancer cells

MicroRNAs (miRNAs) have been demonstrated to exhibit abnormal expression patterns in various types of human cancer. The aim of the present study was to identify a novel tumor suppressor microRNA (miR) and investigate its physiological function and mechanism in renal cell carcinoma (RCC). The expression levels of miRNA (miR)‑362‑3p expres were measured in 47 pairs of RCC and adjacent normal tissue samples, using reverse transcription-quantitative polymerase chain reaction analysis. In addition, miR‑362‑3p was transfected into renal cancer cells to investigate its role in the regulation of cell proliferation, migration, invasion, apoptosis and cell cycle. Identification of the target gene of miR‑362‑3p was performed using luciferase reporter assays and western blot analyses. The results demonstrated that the expression levels of miR‑362‑3p were downregulated in the RCC tissue samples, compared with the adjacent normal tissue samples. The upregulation of miR‑362‑3p using a synthesized mimic suppressed the proliferation, migration and invasion of the renal cancer cells, and induced cell apoptosis and G1 phase arrest. Further experiments demonstrated that the overexpression of miR‑362‑3p resulted in decrease expression levels of nemo-like kinase. These results suggested that miR-362-3p functions as a tumor suppressor in RCC, and may serve as a potential molecular target in the treatment of RCC.

Prognostic value of miR-106b expression in breast cancer patients

BACKGROUND

The aim of the present study was to evaluate whether the level of expression of tissue or plasma miR-106b can be used to predict clinical outcomes in breast cancer patients.

METHODS

Both tissue and plasma samples were collected and analyzed from 173 patients with primary breast cancer and a set of 50 women with fibroadenoma. The relative expression levels of miR-106b were determined using real-time quantitative reverse transcription polymerase chain reaction and in situ hybridization.

RESULTS

The levels of miR-106b were upregulated in both tissue and plasma samples from breast cancer patients. The expression levels showed a linear correlation (rs = 0.748, P < 0.001) and were significantly correlated with tumor size, Ki67 expression, and lymph node metastasis (all P < 0.05). Patients with high miR-106b expression levels tended to have shorter disease-free survival times and overall survival times (P < 0.001). In a Cox regression model, high-level tissue and plasma miR-106b expression were unfavorable prognostic factors, and receiver-operating characteristic analysis revealed that the tissue and plasma miR-106b levels provided considerable diagnostic accuracy, yielding an area under the ROC curve of 0.785 and 0.856, respectively.

CONCLUSIONS

MiR-106b was found to be associated with a high risk of recurrence of breast cancer, and miR-106b is a putative plasma marker for risk assessment in patients with breast cancer.

miR-625 down-regulation promotes proliferation and invasion in esophageal cancer by targeting Sox2

miR-625 has been reported to exhibit abnormal expression in esophageal cancer (EC), but the mechanism and functions of miR-625 in esophageal cancer remain unclear. miR-625 down-regulation and Sox2 up-regulation were validated by qRT-PCR in 158 EC samples. Low expression of miR-625 promotes cell proliferation and invasion, while high expression of miR-625 has the opposite effect. Sox2, a target gene of miR-625, was examined by luciferase assay and western blot. Our data suggest that miR-625 may regulate the biological processes of EC via controlling Sox2 expression.

Recent progress in research of gastroesophageal reflux disease: Pathogenesis, diagnosis and treatment

The incidence of gastroesophageal reflux disease has been increasing annually in China. The emergence of new techniques in recent years has not only facilitated the diagnosis of this complex disease but also improved the understanding of the pathogenesis of this disease. Nowadays much attention is paid to adverse reactions of drugs such as proton pump inhibitors and prokinetic agents for gastroesophageal reflux disease, which has promoted the development of new treatments for gastroesophageal reflux disease. In this review, we will summarize recent progress in research of gastroesophageal reflux disease in terms of its pathogenesis, diagnosis and treatment.