Ti Yang

Alteration of serum miR-206 and miR-133b is associated with lung carcinogenesis induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone.

The alteration of microRNA (miRNA) expression plays an important role in chemical carcinogenesis. Presently, few reports have been published that concern the significance of circulating miRNAs in lung carcinogenesis induced by environmental carcinogens. The purpose of this study was to identify serum miRNAs that could be associated with lung carcinogenesis induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Male F344 rats were systemically administered with NNK. The rat serum differential expression profiles of miRNAs were analyzed by small RNA solexa sequencing. Using quantitative real-time PCR, the differentially expressed serum miRNAs were identified in each individual rat. Serum miR-206 and miR-133b were selected for further identification in rat serum at different stages of lung carcinogenesis; we detected the levels of serum miR-206 and miR-133b in lung cancer tissues induced by NNK. NNK causes significant alteration of serum miRNA expression. Compared to the control group, serum miR-206 and miR-133b were significantly up-regulated in the early stage of NNK-induced lung carcinogenesis. miR-206 and miR-133b exhibited low-expression in lung cancer tissues. Our results demonstrate that lung carcinogen NNK exposure changes the expression of serum miRNAs. Serum miR-206 and miR-133b could be associated with lung carcinogenesis induced by NNK.

Deregulation of Serum MicroRNA Expression Is Associated with Cigarette Smoking and Lung Cancer

Lung cancer is the leading cause of cancer-related death and cigarette smoking is the main risk factor for lung cancer. Circulating microRNAs (miRNAs) are considered potential biomarkers of various cancers, including lung cancer. However, it is unclear whether changes in circulating miRNAs are associated with smoking and smoking-related lung cancer. In this study, we determined the serum miRNA profiles of 10 nonsmokers, 10 smokers, and 10 lung-cancer patients with miRCURY LNA microRNA arrays. The differentially expressed miRNAs were then confirmed in a larger sample. We found that let-7i-3p and miR-154-5p were significantly downregulated in the sera of smokers and lung-cancer patients, so the serum levels of let-7i-3p and miR-154-5p are associated with smoking and smoking-related lung cancer. The areas under receiver operating characteristic curves for let-7i-3p and miR-154-5p were approximately 0.892 and 0.957, respectively. In conclusion, our results indicate that changes in serum miRNAs are associated with cigarette smoking and lung cancer and that let-7i-3p and miR-154-5p are potential biomarkers of smoking-related lung cancer.

A novel regulatory network among LncRpa, CircRar1, MiR-671 and apoptotic genes promotes lead-induced neuronal cell apoptosis

Lead is a metal that has toxic effects on the developing nervous system. However, the mechanisms underlying lead-induced neurotoxicity are not well understood. Non-coding RNAs (ncRNAs) play an important role in epigenetic regulation, but few studies have examined the function of ncRNAs in lead-induced neurotoxicity. We addressed this in the present study by evaluating the functions of a long non-coding RNA (named lncRpa) and a circular RNA (named circRar1) in a mouse model of lead-induced neurotoxicity. High-throughput RNA sequencing showed that both lncRpa and circRar1 promoted neuronal apoptosis. We also found that lncRpa and circRar1 induced the upregulation of apoptosis-associated factors caspase8 and p38 at the mRNA and protein levels via modulation of their common target microRNA miR-671. This is the first report of a regulatory interaction among a lncRNA, circRNA, and miRNA mediating neuronal apoptosis in response to lead toxicity.

Functional role and mechanism of lncRNA LOC728228 in malignant 16HBE cells transformed by anti-benzopyrene-trans-7,8-dihydrodiol-9,10-epoxide.

Lung cancer is a major health problem, and is considered one of the deadliest cancers in humans. It is refractory to current treatments, and the mechanisms of lung cancer are unknown. Long noncoding RNAs (lncRNAs) are involved in various biological processes and human diseases. However, the exact functional roles and mechanisms of lncRNAs are largely unclear. In this study, we attempted to identify lung‐cancer‐related lncRNAs. We found changes in lncRNA expression in the anti‐benzo(a) pyrene‐7,8‐diol‐9,10‐epoxide (anti‐BPDE)‐transformed human bronchial epithelial cell line (16HBE‐T cells) using microarrays and qRT–PCR. Of these lncRNAs, LOC728228 was upregulated relative to its expression in control untransformed16HBE (16HBE‐N) cells. LOC728228 knockdown inhibited cell proliferation, caused G0/G1‐phase cell‐cycle arrest, reduced cellular migration, suppressed colony formation in vitro, and inhibited tumor growth in a nude mouse xenograft model. LOC728228 knockdown also suppressed cyclin D1 expression, and the depletion of cyclin D1 induced G0/G1‐phase cell‐cycle arrest and inhibited cell proliferation, thus influencing the malignant potential of cancer cells. In summary, our results suggest that lncRNA LOC728228 has an oncogene‐like function and plays a vital role in human lung cancer.

Altered miRNA Expression Profiles and miR-1a Associated With Urethane-Induced Pulmonary Carcinogenesis

MicroRNAs (miRNAs) are small RNA molecules that regulate posttranscriptional gene expression. Previous research has suggested that aberrant miRNA expression often plays a critical role in many types of cancer, including lung cancer. However, the exact miRNAs that are involved in pulmonary carcinogenesis remain unclear. We investigated the miRNA-based molecular changes that occur in urethane-induced carcinogenicity and identified specific miRNA deregulation in pulmonary carcinogenesis induced by urethane. In this study, we used a lung cancer model in which Balb/c mice were exposed to urethane via ip injection once a week for four consecutive weeks. The mice were then killed in weeks 6, 12, or 24. Two small RNA libraries were constructed with the total RNA from the lung tumor and normal adjacent lung tissues of the urethane-injected mice collected in week 24. Using Solexa sequencing, we identified a plethora of differentially expressed miRNAs and predicted nine novel miRNAs. Further analysis demonstrated the sustainable downregulation of miR-1a in the lung tissues in lung carcinogenesis induced by urethane. The levels of miR-1a were also reduced in the serum. Our findings indicate that urethane exposure alters the expression of a cluster of miRNAs. The simultaneous downregulation of miR-1a in lung tissues and serum in urethane-induced pulmonary carcinogenesis suggests that miR-1a is associated with tumorigenesis.

LncRNA LINC00341 mediates PM2.5-induced cell cycle arrest in human bronchial epithelial cells

Fine particulate matter (PM2.5) could adhere to many toxic substances and cause respiratory diseases.However, the associated pathogenic mechanism remains unclear. In this study, we investigated the effects of PM2.5 on cell cycle progression in human bronchial epithelial cells (16HBE) and the underlying mechanism mediated by lncRNAs. PM2.5 treatment inhibited cell proliferation in 16HBE cells in a dose-dependent manner. The results of flow cytometry assay (FCM) showed that PM2.5 induced cell apoptosis and cell cycle arrest at G2/M phase. The lncRNA microarray analysis indicated that treatment with PM2.5 led to the alteration of lncRNA expression profiles. qRT-PCR were performed to confirm the differential expression of several candidate lncRNAs. lncRNA LINC00341 was significantly up-regulated in 16HBE cell after PM2.5 treatment. Further functional studies showed that knockdown of lncRNA LINC00341 reversed PM2.5-induced G2/M phase cell cycle arrest and p21 expression. These results suggest that up-regulation of the lncRNA LINC00341 mediates PM2.5-induced cell cycle arrest at the G2/M phase, and probably through regulating the expression of p21.

Identification of a long non-coding RNA NR_026689 associated with lung carcinogenesis induced by NNK

Long non-coding RNAs (lncRNA) are thought to be important epigenetic regulators involved in the development of a variety of cancers. Alterations in lncRNA expression are associated with exposure to chemical carcinogens. However, it is still unclear whether lncRNA expression during lung carcinogenesis is induced by chemical carcinogens. In this study, using NNK-induced rat lung cancer model established by our previous study, we determined the lncRNA expression profiles, and an alteration in lncRNA expression was observed in lung cancer tissues and blood in the NNK treatment group. Using quantitative reverse-transcription PCR (qRT-PCR), five differentially expressed lncRNAs were further detected and validated. We identified a novel lncRNA, NR_026689, which showed increased expression in lung cancer tissues induced by NNK and the alteration of lncRNA NR_026689 was specifically observed in lung tissue. The level of NR_026689 was determined and significantly increased in rat whole blood at the 10th and 20th week after NNK treatment to evaluate it as a potential early marker for lung cancer. Together, these findings suggest that lncRNA NR_026689 may be a potential early biomarker for lung cancer and is associated with lung carcinogenesis induced by NNK.

4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone Induces Circulating MicroRNA Deregulation in Early Lung Carcinogenesis

OBJECTIVE To study the alteration of circulating microRNAs in 4-(methylnitrosamino)-1-(3-pyridyl) -1-butanone (NNK)-induced early stage lung carcinogenesis. METHODS A lung cancer model of male F344 rats was induced with systemic NNK and levels of 8 lung cancer-associated miRNAs in whole blood and serum of rats were measured by quantitative RT-PCR of each at weeks 1, 5, 10, and 20 following NNK treatment. RESULTS No lung cancer was detected in control group and NNK treatment group at week 20 following NNK treatment. The levels of some circulating miRNAs were significantly higher in NNK treatment group than in control group. The miR-210 was down-regulated and the miR-206 was up-regulated in NNK treatment group. The expression level of circulating miRNAs changed from week 1 to week 20 following NNK treatment. CONCLUSION The expression level of circulating miRNAs is related to NNK-induced early stage lung carcinogenesis in rats and can therefore serve as its potential indicator.

The linc00152 Controls Cell Cycle Progression by Regulating CCND1 in 16HBE Cells Malignantly Transformed by Cigarette Smoke Extract

Smoking is one of the major environmental risk factors for lung cancer. In recent years, the role of long-chain noncoding RNAs (lncRNAs) in chemical carcinogenesis has attracted extensive research attention. In this study, we treated human bronchial epithelial cells with cigarette smoke extract (CSE) at a dose of 2 μg/ml to establish a malignantly transformed cellular model (16HBE-M). Screening of lncRNAs highly expressed in transformed cells via differential analysis revealed a crucial role of linc00152 in CSE-induced malignant transformation. The linc00152 serum level in CSE-exposed individuals was increased in a dose-dependent manner and its high expression associated with metastasis and proliferation of lung cancer tissue. In malignantly transformed 16HBE-M cells, linc00152 was involved in regulation of cell adhesion, epithelial transition and other malignant phenotypes, which in turn, affected in vivo metastasis. Interference with linc00152 expression led to G1/S arrest and inhibition of proliferation of 16HBE-M and H1299 cells. Furthermore, linc00152 promoted cyclin D1 expression and G1/S transition by functioning as an endogenous competitive RNA targeting miR-193b. Our collective findings supported a critical regulatory role of linc00152 in cell cycle alterations and abnormal proliferation in CSE-induced malignant transformation of human bronchial epithelial cells.

Editor’s Highlight: lncRNAL20992 Regulates Apoptotic Proteins to Promote Lead-Induced Neuronal Apoptosis

Lead is a heavy metal pollutant that is widely present in the environment and can seriously harm human health, especially the nervous system. Long noncoding RNAs (lncRNAs) play important roles in many physiological and pathological processes; however, there remains a lack of in-depth studies on the molecular mechanisms associated with lead neurotoxicity. Here, our results showed that lead exposure inhibited cell proliferation and promoted cell apoptosis. We observed that lncRNAL20992 was significantly upregulated in a lead-induced neuronal-injury cell model according to quantitative reverse transcription polymerase chain reaction. Silencing lncRNAL20992 revealed its significant functions involved in promoting cell apoptosis and inhibiting cell proliferation according to cell-counting kit-8, EdU assay, terminal deoxynucleotidyl transferase dUTP nick-end labeling, and western blot. To elucidate the molecular mechanisms of lncRNAL20992, we used RNA pulldown mass spectrometry combined with bioinformatics analysis to discover 4 proteins (AIFM1, HSP7C, GRP78, and LMNA) that interacted with lncRNAL20992. Western blot analysis indicated that lncRNAL20992 involved in lead-induced neuronal injury was mediated by the 4 proteins. Our study constitutes the first investigation of the functions and related mechanisms of lncRNAL20992 and offered valuable insight into understanding the roles of lncRNA in lead-induced neurotoxicity.