Yijiang Chen

Down-Regulation of MiR-30c Promotes the Invasion of Non-Small Cell Lung Cancer by Targeting MTA1

Background: The connection between microRNA expression and lung cancer development has been identified in recent literature. However, the mechanism of microRNA has been poorly elucidated in non-small-cell lung cancer (NSCLC). Methods and Results: Comparing with adjacent tissues (n=75), miR-30c has a lower expression in lung cancer specimens (n=75). The knockdown of miR-30c enhanced the invasion of A549 cells; meanwhile, the overexpression of miR-30c could reverse the effect of the knockdown of miR-30c in vitro. A luciferase assay revealed that miR-30c was directly bound to the 3‘-untranslated regions (3‘-UTR) of MTA1. QRT-PCR and western blot shows MTA1 was up-regulated in mRNA and protein levels. The effect taken on the invasion of NSCLC by overexpression of MTA1 works the same as down-regulated miR-30c. Conclusion: miR-30c may play a pivotal role in controlling lung cancer invasion through regulating MTA1in NSCLC.

Downregulation of miR-638 promotes invasion and proliferation by regulating SOX2 and induces EMT in NSCLC.

Aberrant expression of microRNAs has been shown to regulate the biological processes of lung cancer cells. However, the role of miR‐638 in the development of NSCLC is still unclear. In this study, low miR‐638 and high SOX2 were shown to be associated with tumor size and metastasis of NSCLC patients. Downregulated miR‐638 could promote cell invasion and proliferation, while high miR‐638 expression reversed the effect. Furthermore, miR‐638 could regulate SOX2 by directly binding to its 3′‐UTR. Silencing of SOX2 by siRNA partially abolished the enhancement of cell invasion and proliferation induced by downregulated miR‐638. Aberrant miR‐638 expression could modulate the expression levels of markers of epithelial‐to‐mesenchymal transition. Our results indicate that miR‐638 may play a pivotal role in the development of NSCLC.

Low expression of microRNA-30c promotes invasion by inducing epithelial mesenchymal transition in non-small cell lung cancer

MicroRNA (miR)‑30c has been identified as a tumor suppressor gene in numerous diseases. Aberrant miR‑30c expression has been associated with the invasion of different types of cancer. However, the potential mechanisms underlying the association between miR‑30c and invasion has been poorly elucidated in non‑small‑cell lung cancer (NSCLC). In the present study, quantitative polymerase chain reaction demonstrated that the expression of miR‑30c was reduced in lung cancer specimens (n=85). Suppressing the expression of miR‑30c promoted the invasion of A549 cells, while overexpressed miR‑30c inhibited the invasion of A549 cells. Furthermore, aberrant miR‑30c expression was able to control the expression levels of markers (E‑cadherin, snail and vimentin) of epithelial mesenchymal transition (EMT). In conclusion, miR‑30c regulated the invasion of NSCLC cells and low miR-30 levels induced EMT.

Up-Regulation of MiR-452 Inhibits Metastasis of Non-Small Cell Lung Cancer by Regulating BMI1

Background/Aims: MicroRNAs (miRNAs) have been regarded as a new class of regulators in cellular processes in non-small cell lung cancer (NSCLC). However, the relationship between miR-452 and the development of NSCLC remains unclear. Methods: qRT-PCR was used to detect the expression of miR-452 and its target gene in NSCLC samples (n=60). The transwell assay was used to test the cell invasion capability. The regulation mechanism was confirmed by luciferase reporter assay and western blot assay. Results: In the current study, a relatively lower miR-452 and higher BMI1 expression levels were confirmed to be associated with advanced tumor stage and more extent of lymph nodes metastasis. In vitro, down-regulated miR-452 could enhance cell invasion capability. Furthermore, miR-452 modulated BMI1 expression by binding to its 3ʹ-UTR. The enhancement of cell invasion capability induced by down-regulated miR-452 was eliminated by repression of BMI1. Conclusions: Our results suggest that miR-452 plays a vital role in development of NSCLC, and this miR-452-BMI1 pathway might generate a novel insight into the treatment of NSCLC.

WT1 promotes cell proliferation in non-small cell lung cancer cell lines through up-regulating cyclin D1 and p-pRb in vitro and in vivo.

The Wilms’ tumor suppressor gene (WT1) has been identified as an oncogene in many malignant diseases such as leukaemia, breast cancer, mesothelioma and lung cancer. However, the role of WT1 in non-small-cell lung cancer (NSCLC) carcinogenesis remains unclear. In this study, we compared WT1 mRNA levels in NSCLC tissues with paired corresponding adjacent tissues and identified significantly higher expression in NSCLC specimens. Cell proliferation of three NSCLC cell lines positively correlated with WT1 expression; moreover, these associations were identified in both cell lines and a xenograft mouse model. Furthermore, we demonstrated that up-regulation of Cyclin D1 and the phosphorylated retinoblastoma protein (p-pRb) was mechanistically related to WT1 accelerating cells to S-phase. In conclusion, our findings demonstrated that WT1 is an oncogene and promotes NSCLC cell proliferation by up-regulating Cyclin D1 and p-pRb expression.

Osteoprotegerin/RANK/RANKL axis and atrial remodeling in mitral valvular patients with atrial fibrillation.

BACKGROUNDnAtrial remodeling is considered as the structural basis for the development and sustaining of atrial fibrillation (AF). Osteoprotegerin (OPG)/receptor activator of nuclear factor-κB (RANK)/RANK ligand (RANKL) axis, a key regulatory system in bone metabolism, was recently identified in some cardiovascular disorders for its regulation to myocardial remodeling. We hypothesized that the OPG/RANK/RANKL axis is involved in development and perpetuation of AF by regulating atrial remodeling.nnnMETHODSnBiopsies of right atrial appendage and clinical data were collected from sex- and age-matched 24 persistent AF, 24 paroxysmal AF, 24 sinus rhythm (SR) patients undergoing isolated mitral valve surgery and 24 healthy heart donors (normal controls).nnnRESULTSnA significantly increasing gradient of atrial expression of OPG, RANKL, RANK and RANKL/OPG ratio was identified in normal controls, SR and AF groups. RANKL/OPG ratio was also found significantly higher in paroxysmal AF than persistent AF. Furthermore, atrial expression and activity of the axis was statistically correlated with collagen III/I levels and ratio and the degree of interstitial fibrosis reflected by collagen volume fraction in right atrial appendages.nnnCONCLUSIONSnThe present findings suggest a potential role for known mediators of bone homeostasis in the pathogenesis of AF and possibly represent new targets for therapeutic intervention in AF.

WT1 enhances proliferation and impedes apoptosis in KRAS mutant NSCLC via targeting cMyc.

Background: A novel link between oncogenic KRAS signalling and WT1 was recently identified. We sought to investigate the role of WT1 and KRAS in proliferation and apoptosis. Methods: KRAS mutations and WT1 (cMyc) expression were detected using Sanger sequencing and real-time PCR in 77 patients with non-small cell lung cancer (NSCLC). Overexpression and knockdown of WT1 were generated with plasmid and siRNA via transient transfection technology in H1299 and H1568 cells. MTT assay for detection of cell proliferation, and TUNEL assay and proteomic profiler assay for apoptosis evaluation were carried out. Dual luciferase reporter assay and ChIP-PCR were performed to validate the effect of WT1 on the cMyc promoter. Results: KRAS mutations showed a negative impact on overall survival (OS). High expressions of WT1 and cMyc were associated with poor OS in KRAS mutant subgroup. The potential mechanisms that WT1 promotes proliferation and impedes apoptosis through affecting multiple apoptosis-related regulators in KRAS mutant NSCLC cells were identified. WT1 could activate cMyc promoter directly in KRAS mutant cells. Conclusion: The results suggest that WT1 and c-MYC expression is important for survival in KRAS mutant tumors as opposed to KRAS wild-type tumors. For treatment of KRAS mutant NSCLC, targeting WT1 and cMyc may provide alternative therapeutic strategies.

Long Noncoding RNA FAL1 Promotes Cell Proliferation, Invasion and Epithelial-Mesenchymal Transition Through the PTEN/AKT Signaling Axis in Non-Small Cell Lung Cancer

Background/Aims: Recently, long non-coding RNAs (lncRNAs) have been found to have many biological effects in different cancer stages. Several studies have revealed that focally amplified lncRNA on chromosome 1 (FAL1) regulates cancer progression via p21. However, the expression and mechanism of FAL1 in non-small cell lung cancer (NSCLC) still remain unclear. Methods: We detected the FAL1 level in NSCLC tissues and in established cell lines using quantitative real-time PCR and evaluated the clinical significance. FAL1 was silenced or overexpressed using siRNA or lentivirus to study whether FAL1 affected cell proliferation, invasion and migration. Xenograft growth and pulmonary metastasis were observed using nude mouse models. The mechanisms were explored with western blotting and immunohistochemistry. Results: FAL1 was significantly overexpressed in NSCLC compared with adjacent normal tissues, and a high level of FAL1 correlated with poor histological grade, increased lymph node metastasis and advanced TNM stage. Loss- and gain-of-function experiments in vitro verified that knockdown of FAL1 inhibited cell proliferation, invasion, migration and EMT via the PTEN/AKT pathway. Furthermore, an in vivo assay confirmed that overexpression of FAL1 facilitated tumor growth and metastasis. Conclusion: FAL1 may promote tumorigenesis and progression of NSCLC through the PTEN/AKT axis, which could lead to lncRNA-related diagnostics and therapeutics in NSCLC.

OPG/RANK/RANKL Axis in Stabilization of Spontaneously Restored Sinus Rhythm in Permanent Atrial Fibrillation Patients after Mitral Valve Surgery

Objective: To investigate the expression of the osteoprotegerin (OPG)/receptor activator of nuclear factor-ĸB (RANK)/RANK ligand (RANKL) axis in the stabilization of spontaneously restored sinus rhythm (SR) in permanent atrial fibrillation (AF) patients after mitral valve (MV) surgery and study its clinical significance. Methods: Clinical data, biopsies of right atrial appendages were collected from 135 permanent AF patients who spontaneously restored SR after conventional isolated MV replacement. A comparison was made between patients who had recurrence of AF within 7 days and patients with persistent SR for more than 7 days. Results: AF patients had an increased expression of RANK, RANKL, and the RANKL/OPG ratio compared to SR patients, and the degree of fibrosis was lower in SR compared to AF in the atria. Moreover, the expressions of RANK, RANKL, and the RANKL/OPG ratio were positively correlated with the degree of fibrosis. Conclusion: These findings suggest that the OPG/RANK/RANKL axis plays important roles in the stabilization of restored SR after MV surgery by stimulating AF-related atrial remodeling in AF patients.

Preoperative Serum Soluble Receptor Activator of Nuclear Factor-κB Ligand and Osteoprotegerin Predict Postoperative Atrial Fibrillation in Patients Undergoing Cardiac Valve Surgery

BACKGROUNDnPostoperative atrial fibrillation (POAF), a frequent complication after cardiac surgery, causes morbidity and prolongs hospitalization. A significant association between circulating osteoprotegerin concentration and atrial fibrillation incidence had been identified. Osteoprotegerin/receptor activator of nuclear factor-κB/receptor activator of nuclear factor-κB ligand (RANKL) axis may also contribute to the development and progression of AF. Herein we sought to determine whether preoperative serum soluble RANKL and osteoprotegerin and soluble RANKL/osteoprotegerin ratio are associated with the incidence of POAF in cardiac surgery patients.nnnMETHODSnWe enrolled 154 patients with preoperative sinus rhythm undergoing isolated cardiac valve surgery. Preoperative venous blood samples were obtained for measurement of serum soluble RANKL and osteoprotegerin. The POAF was defined as the characteristic arrhythmia lasting for at least 30 seconds before discharge. Comparison was made between patients without episode of POAF (sinus rhythm group, n=93) and patients experiencing POAF (atrial fibrillation group, n=61).nnnRESULTSnSerum levels of soluble RANKL and osteoprotegerin and soluble RANKL/osteoprotegerin ratio were significantly higher in the atrial fibrillation group than the sinus rhythm group. In multivariate survival regression, C-reactive protein, ejection fraction, left and right atrial diameters, preoperative use of beta-blocker, duration of ventilation, particularly serum soluble RANKL level, and soluble RANKL/osteoprotegerin ratio independently predicted POAF. According to receiver operating characteristic curve analysis, the best threshold values of serum soluble RANKL level and soluble RANKL/osteoprotegerin ratio for predicting POAF were 3.62 pmol/L and 0.51, respectively.nnnCONCLUSIONSnElevated preoperative serum soluble RANKL level and soluble RANKL/osteoprotegerin ratio are independent predictors for POAF in patients undergoing cardiac valve surgery. These findings have important implications for identifying patients at higher risk of POAF who could be considered for prophylactic therapy.