ERGIC3, which is regulated by miR‐203a,is a potential biomarker for non‐small cell lung cancer

In a previous study, we found that ERGIC3 was a novel lung cancer‐related gene by screening libraries of differentially expressed genes. In this study, we developed a new murine monoclonal antibody (mAb) against ERGIC3. This avid antibody (6‐C4) is well suited for immunohistochemistry, immunoblotting and solid‐phase immunoassays. Furthermore, we systematically investigated expressions of ERGIC3 in a broad variety of normal human tissues and various types of tumors by immunohistochemistry. In normal human tissues, 6‐C4 reacted only in some epithelial cells, such as hepatocytes, gastrointestinal epithelium, ducts and acini of the pancreas, proximal and distal tubules of the kidney, and mammary epithelial cells; however, most normal human tissues were not stained. Moreover, almost all carcinomas that originated from the epithelial cells were positive for 6‐C4, whereas all sarcomas were negative. Notably, 6‐C4 strongly stained non‐small cell lung cancer (NSCLC) cells but did not react with normal lung tissues. Hence, ERGIC3 mAb could be used in histopathological diagnosis and cytopathological testing to detect early‐stage NSCLC. We also studied the mechanisms of ERGIC3 regulation in vitro and in vivo by means of bioinformatics analysis, luciferase reporter assay, miRNA expression profiling and miRNA transfection. Results showed that miR‐203a downregulation induced ERGIC3 overexpression in NSCLC cells.     

Whole blood FPR1 mRNA expression predicts both non‐small cell and small cell lung cancer

While long‐term survival rates for early‐stage lung cancer are high, most cases are diagnosed in later stages that can negatively impact survival rates. We aim to design a simple, single biomarker blood test for early‐stage lung cancer that is robust to preclinical variables and can be readily implemented in the clinic. Whole blood was collected in PAXgene tubes from a training set of 29 patients, and a validation set of 260 patients, of which samples from 58 patients were prospectively collected in a clinical trial specifically for our study. After RNA was extracted, the expressions of FPR1 and a reference gene were quantified by an automated one‐step Taqman RT‐PCR assay. Elevated levels of FPR1 mRNA in whole blood predicted lung cancer status with a sensitivity of 55% and a specificity of 87% on all validation specimens. The prospectively collected specimens had a significantly higher 68% sensitivity and 89% specificity. Results from patients with benign nodules were similar to healthy volunteers. No meaningful correlation was present between our test results and any clinical characteristic other than lung cancer diagnosis. FPR1 mRNA levels in whole blood can predict the presence of lung cancer. Using this as a reflex test for positive lung cancer screening computed tomography scans has the potential to increase the positive predictive value. This marker can be easily measured in an automated process utilizing off‐the‐shelf equipment and reagents. Further work is justified to explain the source of this biomarker.     

PVT1‐derived miR‐1207‐5p promotes breast cancer cell growth by targeting STAT6

Accumulating evidence indicates that ectopic expression of non‐coding RNAs are responsible for breast cancer progression. Increased non‐coding RNA PVT1, the host gene of microRNA‐1207‐5p (miR‐1207‐5p), has been associated with breast cancer proliferation. However, how PVT1 functions in breast cancer is still not clear. In this study, we show a PVT1‐derived microRNA, miR‐1207‐5p, that promotes the proliferation of breast cancer cells by directly regulating STAT6. We first confirm the positive correlated expression pattern between PVT1 and miR‐1207‐5p by observing consistent induced expression by estrogen, and overexpression in breast cancer cell lines and breast cancer patient specimens. Moreover, silence of PVT1 also decreased miR‐1207‐5p expression. Furthermore, increased miR‐1207‐5p expression promoted, while decreased miR‐1207‐5p expression suppressed, cell proliferation, colony formation, and cell cycle progression in breast cancer cell lines. Mechanistically, a novel target of miR‐1207‐5p, STAT6, was identified by a luciferase reporter assay. Overexpression of miR‐1207‐5p decreased the levels of STAT6, which activated CDKN1A and CDKN1B to regulate the cell cycle. We also confirmed the reverse correlation of miR‐1207‐5p and STAT6 expression levels in breast cancer samples. Therefore, our findings reveal that PVT1‐derived miR‐1207‐5p promotes the proliferation of breast cancer cells by targeting STAT6, which in turn controls CDKN1A and CDKN1B expression. These findings suggest miR‐1207‐5p might be a potential target for breast cancer therapy.     

Circulating exosomes contain protein biomarkers of metastatic non‐small‐cell lung cancer

The present study aimed to investigate the overall changes in exosomal proteomes in metastatic and non‐metastatic non‐small‐cell lung cancers (NSCLC) and healthy human serum samples, and evaluate the potential of serum exosomal biomarkers to predict NSCLC metastasis. Tandem mass tags combined with multidimensional liquid chromatography and mass spectrometry analysis were used for screening the proteomic profiles of serum samples. Quantitative proteome, significant pathway, and functional categories of patients with metastatic and non‐metastatic NSCLC and healthy donors were investigated. In total, 552 proteins of the 628 protein groups identified were quantified. Bioinformatics analysis indicated that quantifiable proteins were mainly involved in multiple biological functions, metastasis‐related pathways. Moreover, lipopolysaccharide‐binding proteins (LBP) in the exosomes were found to be well distinguished between patients with metastatic and patients with non‐metastatic NSCLC. Area under the curve (AUC) was 0.803 with a sensitivity of 83.1% and a specificity of 67% (P < .0001). Circulating LBP were also well distinguishable between metastatic and non‐metastatic NSCLC, the AUC was 0.683 with a sensitivity of 79.5% and a specificity of 47.2% (P = .005). This novel study provided a reference proteome map for metastatic NSCLC. Patients with metastatic and non‐metastatic NSCLC differed in exosome‐related proteins in the serum. LBP might be promising and effective candidates of metastatic NSCLC.     

ARHGEF19 interacts with BRAF to activate MAPK signaling during the tumorigenesis of non‐small cell lung cancer

Rho guanine nucleotide exchange factors (RhoGEFs) are proteins that activate Rho GTPases in response to extracellular stimuli and regulate various biologic processes. ARHGEF19, one of RhoGEFs, was reported to activate RhoA in the Wnt‐PCP pathway controlling convergent extension in Xenopus gastrulation. The goal of our study was to identify the role and molecular mechanisms of ARHGEF19 in the tumorigenesis of non‐small cell lung cancer (NSCLC). ARHGEF19 expression was significantly elevated in NSCLC tissues, and ARHGEF19 levels were significantly associated with lymph node status, distant metastasis and TNM stage; Patients with high ARHGEF19 levels had poor overall survival (OS) and progression‐free survival (PFS). Our investigations revealed that ARHGEF19 overexpression promoted the cell proliferation, invasion and metastasis of lung cancer cells, whereas knockdown of this gene inhibited these processes. Mechanistically, ARHGEF19 activated the mitogen‐activated protein kinase (MAPK) pathway in a RhoA‐independent manner: ARHGEF19 interacted with BRAF and facilitated the phosphorylation of its downstream kinase MEK1/2; both the Dbl homology (DH) and Pleckstrin homology (PH) domains of ARHGEF19 were indispensable for the phosphorylation of MEK1/2. Furthermore, downregulation of miR‐29b was likely responsible for the increased expression of ARHGEF19 in lung cancer tissues and, consequently, the abnormal activation of MAPK signaling. These findings suggest that ARHGEF19 upregulation, due to the low expression of miR‐29 in NSCLC tissues, may play a crucial role in NSCLC tumorigenesis by activating MAPK signaling. ARHGEF19 could serve as a negative prognostic marker as well as a therapeutic target for NSCLC patients.     

MicroRNA‐338‐5p reverses chemoresistance and inhibits invasion of esophageal squamous cell carcinoma cells by targeting Id‐1

5‐Fluorouracil (5‐FU) is a chemotherapeutic agent commonly used to treat esophageal squamous cell carcinoma (ESCC), but acquisition of chemoresistance frequently occurs and the underlying mechanisms are not fully understood. We found that microRNA (miR)‐338‐5p was underexpressed in ESCC cells with acquired 5‐FU chemoresistance. Forced expression of miR‐338‐5p in these cells resulted in downregulation of Id‐1, and restoration of both in vitro and in vivo sensitivity to 5‐FU treatment. The effects were abolished by reexpression of Id‐1. In contrast, miR‐338‐5p knockdown induced 5‐FU resistance in chemosensitive esophageal cell lines, and knockdown of both miR‐338‐5p and Id‐1 resensitized the cells to 5‐FU. In addition, miR‐338‐5p had suppressive effects on migration and invasion of ESCC cells. Luciferase reporter assay confirmed a direct interaction between miR‐338‐5p and the 3′‐UTR of Id‐1. We also found that miR‐338‐5p was significantly downregulated in tumor tissue and serum samples of patients with ESCC. Notably, low serum miR‐338‐5p expression level was associated with poorer survival and poor response to 5‐FU/cisplatin‐based neoadjuvant chemoradiotherapy. In summary, we found that miR‐338‐5p can modulate 5‐FU chemoresistance and inhibit invasion‐related functions in ESCC by negatively regulating Id‐1, and that serum miR‐338‐5p could be a novel noninvasive prognostic and predictive biomarker in ESCC.     

Tumor‐derived exosomal proteins as diagnostic biomarkers in non‐small cell lung cancer

Accumulating evidence supports a role for exosomal protein in diagnosis. The purpose of this study was to identify the tumor‐derived exosomal biomarkers in the serum that improve the diagnostic value in Chinese non‐small cell lung cancer (NSCLC) patients. Serum exosomes were isolated from healthy donors (n = 46) and NSCLC patients (n = 125) by ultracentrifugation and were characterized using transmission electron microscopy, qNano, and immunoblotting. Proteomic profiles (by mass spectrometry) revealed multiple differentially expressed proteins in the healthy and NSCLC groups. The exosomal expression levels of alpha‐2‐HS‐glycoprotein (AHSG) and extracellular matrix protein 1 (ECM1) increased significantly in the NSCLC patients compared to the healthy group. Alpha‐2‐HS‐glycoprotein showed diagnostic values with a maximum area under the receiver operating characteristic curve (AUC) as 0.736 for NSCLC vs healthy individuals (P < .0001) and 0.682 for early stage NSCLC vs healthy individuals (P < .01). Extracellular matrix protein 1 showed the diagnostic capacity with AUC values of 0.683 (P < .001) and 0.656 (P < .05) in cancer and early stage NSCLC compared to healthy individuals. When AHSG was combined with ECM1, the AUCs were 0.795 and 0.739 in NSCLC and early stage patients, respectively. Taken together, the combination of AHSG, ECM1, and carcinoembryonic antigen improved the diagnostic potential of NSCLC. The diagnosis values were AUC of 0.938 for NSCLC and 0.911 for early stage NSCLC vs healthy individuals. Our results suggest that novel proteomic signatures found in serum exosomes of NSCLC patients show potential usefulness as diagnostic tools.     

MiR‐503 targets PI3K p85 and IKK‐β and suppresses progression of non‐small cell lung cancer

A microRNA usually has the ability to coordinately repress multiple target genes and therefore are associated with many pathological conditions such as human cancer. Our understanding of the biological roles of microRNAs in lung cancer, however, remains incomplete. In this study, we identified miR‐503 as a tumor‐suppressive microRNA in human non‐small cell lung carcinoma (NSCLC), whose expression level correlates inversely with overall survival in NSCLC patients. Ectopic expression of miR‐503 suppressed tumor cell proliferation and metastasis‐related traits in vitro as well as in vivo, supporting a anti‐cancer role of the microRNA in NSCLC progression. Mechanistic study revealed that oncogenic PI3K p85 and IKK‐β were direct targets of miR‐503. Overexpression of either PI3K p85 or IKK‐β partially restored the malignant properties of NSCLC cells in the presence of miR‐503. Taken together, our data demonstrate miR‐503 inhibits the malignant phenotype of NSCLC by targeting PI3K p85 and IKK‐β and might play a suppressive role in the pathogenesis of NSCLC, thus providing new insights in developing novel diagnostic and therapeutic approaches.     

Genetic variants of JNK and p38α pathways and risk of non‐small cell lung cancer in an Eastern Chinese population

The JNK and p38α pathways play an important role in carcinogenesis. Therefore, we hypothesize that single nucleotide polymorphisms (SNPs) of genes involved in these pathways are associated with risk of lung cancer. We first selected and genotyped 11 independent SNPs of the JNK and p38α pathway‐related genes in a discovery set of 1,002 non‐small cell lung cancer (NSCLC) cases and 1,025 cancer‐free controls of Eastern Chinese. Then, we validated those significant SNPs in a replication set of 1,333 NSCLC cases and 1,339 cancer‐free controls of Eastern Chinese. Multifactor dimensionality reduction (MDR) and classification and regression tree (CART) analyses were used to identify interactions between significant SNPs and other covariates. In both discovery and replication as well as their pooled analysis, carriers of GADD45G rs8252T variant genotypes had a significantly lower risk of NSCLC (adjusted OR = 0.81 and 0.79, 95% CI = 0.72–0.92 and 0.64–0.99 and p = 0.001 and 0.040 for dominant and recessive genetic models, respectively) and carriers of MAP2K7 rs3679T variant genotypes had an increased risk of NSCLC (adjusted OR = 1.19 and 1.29, 95% CI = 1.05–1.34 and 1.09–1.54 and p = 0.005 and 0.004 for dominant and recessive genetic models, respectively). Furthermore, rs8252 variant CT/TT carriers showed significantly higher levels of GADD45G mRNA expression than CC carriers in the target tissues. We observed some evidence of interactions between rs8252 genotypes and sex in NSCLC risk. These results indicate that GADD45G rs8252 and MAP2K7 rs3679 SNPs may be susceptibility biomarkers for NSCLC in Eastern Chinese populations.