Exosome analysis in tumor-draining pulmonary vein identifies NSCLC patients with higher risk of relapse after curative surgery

Since tumor-draining pulmonary vein blood (PV) is enriched in tumor-secreted products, we hypothesized that it would also be enriched in tumor-derived exosomes, which would be important in the metastasis process. We characterized exosomes from PV of 61 resected non-small cell lung cancer (NSCLC) patients to evaluate its potential as relapse biomarkers. Exosomes were characterized using transmission electron microscopy, western blot and nanoparticle tracking analysis and we examined time to relapse (TTR) and overall survival (OS). Differences between PV and peripheral vein were found. PV was enriched in smaller exosomes than the paired peripheral vein (p = 0.01). Moreover, PV exosome size mode was able to identify relapsed patients (Area under the curve [AUC] = 0.781; 95%CI: 0.6641-0.8978), in whom exosome size was smaller (<112 nm; p < 0.001). The combination of PV exosome size and N (lymph node involvement) showed an AUC of 0.89 (95%CI: 0.80-0.97). Moreover, smaller PV exosome size was associated with shorter TTR (28.3 months vs. not reached, p < 0.001) and OS (43.9 months vs. not reached, p = 0.009). Multivariate analyses identified PV exosome size and stage as independent prognostic markers for TTR and OS. PV exosome size is a promising relapse biomarker after surgery that can add valuable information to clinical variables

YKT6 expression, exosome release, and survival in non-small cell lung cancer

BACKGROUND: Cancer-derived exosomes are involved in metastasis. YKT6 is a SNARE protein that participates in the regulation of exosome production and release, but its role in non-small cell lung cancer (NSCLC) has not been examined. MATERIALS AND METHODS: Ultracentrifugation-purified exosomes from the A549 cell line were studied by CRYO-TEM, nanoparticle tracking analysis and western blot (TSG101 marker). YKT6 was inhibited using a DsiRNA and selected pre-microRNAs. MicroRNAs targeting YKT6 were validated by Renilla/Luciferase assay and western blot. YKT6 expression and its prognostic impact were analyzed in 98 tissue specimens from resected NSCLC patients. RESULTS: Membranous nanosized vesicles (mode size: 128nm) with TSG101 protein were purified from A549 cells. YKT6 inhibition reduced exosome release by 80.9%. We validated miR-134 and miR-135b as miRNAs targeting YKT6, and transfection with the pre-miRNAs also produced a significant reduction in exosome release. The analysis of YKT6 in tumor samples showed that patients with high levels had shorter disease-free and overall survival. CONCLUSIONS: YKT6 is a key molecule in the regulation of exosome release in lung cancer cells and is in turn precisely regulated by miR-134 and miR-135b. Moreover, YKT6 levels impact prognosis of resected NSCLC patients

Extracellular Vesicle lincRNA-p21 Expression in Tumor-Draining Pulmonary Vein Defines Prognosis in NSCLC and Modulates Endothelial Cell Behavior

Hypoxia-induced upregulation of lincRNA-p21 in tumor tissue was previously shown by our group to be related to poor prognosis in resected non-small cell lung cancer (NSCLC) patients. In the present study, we have evaluated the presence of lincRNA-p21 in extracellular vesicles (EVs) from NSCLC patients and assessed its potential as a prognostic biomarker. High EV lincRNA-p21 levels in blood from the tumor-draining vein were associated with shorter time to relapse and shorter overall survival. Moreover, the multivariate analysis identified high lincRNA-p21 levels as an independent prognostic marker. In addition, lincRNA-p21 was overexpressed in H23 and HCC44 NSCLC cell lines and their derived EVs under hypoxic conditions. Functional assays using human umbilical vein endothelial cells (HUVECs) showed that tumor-derived EVs enriched in lincRNA-p21 affected endothelial cells by promoting tube formation and enhancing tumor cell adhesion to endothelial cells. Additionally, the analysis of selected EV microRNAs related to angiogenesis and metastasis showed that the microRNAs correlated with EV lincRNA-p21 levels in both patients and cell lines. Finally, EV co-culture with HUVEC cells increased the expression of microRNAs and genes related to endothelial cell activation. In conclusion, EV lincRNA-p21 acts as a novel prognosis marker in resected NSCLC patients, promoting angiogenesis and metastasis

Clinical significance of long non-coding RNA HOTTIP in early-stage non-small-cell lung cancer

Background HOTTIP, a long non-coding RNA located in the HOXA cluster, plays a role in the patterning of tissues with mesodermal components, including the lung. Overexpression of HOXA genes, including HOTTIP, has been associated with a more aggressive phenotype in several cancers. However, the prognostic impact of HOTTIP has not yet been explored in non-small-cell lung cancer (NSCLC). We have correlated HOTTIP expression with time to relapse (TTR) and overall survival (OS) in early-stage NSCLC patients. Methods Ninety-nine early-stage NSCLC patients who underwent surgical resection in our center from June 2007 to November 2013 were included in the study. Mean age was 66; 77.8% were males; 73.7% had stage I disease; and 55.5% had adenocarcinoma. A validation data set comprised stage I-II patients from The Cancer Genome Atlas (TCGA) Research Network. Results HOTTIP was expressed in all tumor samples and was overexpressed in squamous cell carcinoma (p = 0.007) and in smokers (p = 0.018). Patients with high levels of HOTTIP had shorter TTR (78.3 vs 58 months; p = 0.048) and shorter OS (81.2 vs 61 months; p = 0.023) than those with low levels. In the multivariate analysis, HOTTIP emerged as an independent prognostic marker for TTR (OR: 2.05, 95%CI: 1-4.2; p = 0.05), and for OS (OR: 2.31, 95%CI: 1.04-5.1; p = 0.04). HOTTIP was validated as a prognostic marker for OS in the TCGA adenocarcinoma cohort (p = 0.025). Moreover, we identified a 1203-mRNA and a 61-miRNA signature that correlated with HOTTIP expression. Conclusions The lncRNA HOTTIP can be considered a prognostic biomarker in early-stage NSCLC

Role of the epithelial-mesenchymal transition-related circular RNA, circ-10720, in non-small-cell lung cancer

Background: Circular RNAs (circRNAs) are non-coding RNAs with a circular structure that have recently emerged as important regulators of tumorogenesis. Recently, several circRNAS, including circ-10720 have been related to epithelial-mesenchymal transition (EMT) process. In the present study, we have analyzed the role of circ-10720 in non-small-cell lung cancer (NSCLC) and studied its prognostic relevance in resected stage I-IIIa NSCLC patients. Methods: Circ-10720 expression was analyzed using a custom TaqMan assay in four NSCLC cell lines (HCC44, A549, H23 and H1299) and in the normal immortalized lung cell line BEAS2B. Silencing of circ10720 was performed using two custom siRNAs which were transfected using lipofectamine 2000. Protein levels were evaluated by Western blot and immunofluorescence. Wound healing and invasion assays were performed to evaluate the impact the circRNA on cell motility. Apoptosis was analyzed by evaluation of Caspase 3-7 activity and proliferation by MTS assay. Moreover, the expression levels of the circRNA were studied in 119 resected NSCLC patients. The expression in tumor tissue was correlated with the main clinicopathological characteristics and with time to relapse (TTR). Results: Circ-10720 was overexpressed in HCC44 and A549 and underexpressed in H23 and H1299 NSCLC cell lines in comparison to BEAS2B normal immortalized lung cell line. CircRNA knockdown in the two circ-10720 overexpressing cell lines was associated with a decrease of Vimentin (VIM) and an increase of E-cadherin (CDH1) protein levels, loss of mesenchymal phenotype, and a significant reduction of migration and invasion capacity. After silencing circ-10720, the apoptosis rate increased and the proliferation was significantly reduced. Furthermore, circ-10720 was upregulated in tumor vs. normal tissue from 119 resected NSCLC patients. In the group of patients not receiving adjuvant treatment, those with high levels of circ-10720 had a shorter TTR than those with low levels and emerged as an independent prognostic value in the multivariate analysis. In tumor tissue, circ-10720 levels positively correlated with the EMT gene Twist1 levels. Conclusions: Circ-10720 regulates EMT, apoptosis and proliferation and acts as a biomarker of relapse in NSCLC

miR-141 and miR-200c as markers of overall survival in early stage non-small cell lung cancer adenocarcinoma

Several treatments in non-small cell lung cancer (NSCLC) are histology-dependent, and the need for histology-related markers is increasing. MicroRNAs (miRNAs) are promising molecular markers in multiple cancers and show differences in expression depending on histological subtype. The miRNA family miR-200 has been associated with the regulation of epithelial-mesenchymal (EMT)/mesenchymal-epithelial transition (MET). EMT involves profound phenotypic changes that include the loss of cell-cell adhesion, the loss of cell polarity, and the acquisition of migratory and invasive properties that facilitates metastasis. A dual role for the miR-200 family in the prognosis of several tumors has been related to tumor cell origin. However, the prognostic role and function of miR-200 family in early-stage NSCLC adenocarcinoma and squamous cell carcinoma (SCC) have not been well established. Methods: miRNA expression was determined using TaqMan assays in 155 tumors from resected NSCLC patients. Functional studies were conducted in three NSCLC cell lines: H23, A-549 and HCC-44. Results: High miR-200c expression was associated with shorter overall survival (OS) in the entire cohort (p = 0.024). High miR-200c (p = 0.0004) and miR-141 (p = 0.009) expression correlated with shorter OS in adenocarcinoma - but not in SCC. In the multivariate analysis, a risk score based on miR-141 and miR-200c expression emerged as an independent prognostic factor for OS in the entire cohort (OR, 2.787; p = 0.033) and in adenocarcinoma patients (OR, 10.649; p = 0.002). Functional analyses showed that miR-200c, was related to mesenchymal-epithelial transition (MET) and affected cell migration and E-cadherin levels, while overexpression of miR-141 reduced KLF6 protein levels and produced an increase of secretion of VEGFA in vitro (H23, p = 0.04; A-549, p = 0.03; HCC-44, p = 0.02) and was associated with higher blood microvessel density in patient tumor samples (p<0.001). Conclusion: High miR-141 and miR-200c expression are associated with shorter OS in NSCLC patients with adenocarcinoma through MET and angiogenesis

Characterization of the MicroRNA Cargo of Extracellular Vesicles Isolated from a Pulmonary Tumor-Draining Vein Identifies miR-203a-3p as a Relapse Biomarker for Resected Non-Small Cell Lung Cancer.

In resected non-small cell lung cancer (NSCLC), post-surgical recurrence occurs in around 40% of patients, highlighting the necessity to identify relapse biomarkers. An analysis of the extracellular vesicle (EV) cargo from a pulmonary tumor-draining vein (TDV) can grant biomarker identification. We studied the pulmonary TDV EV-miRNAome to identify relapse biomarkers in a two-phase study (screening and validation). In the screening phase, a 17-miRNA relapse signature was identified in 18 selected patients by small RNAseq. The most expressed miRNA from the signature (EV-miR-203a-3p) was chosen for further validation. Pulmonary TDV EV-miR-203a-3p was studied by qRT-PCR in a validation cohort of 70 patients, where it was found to be upregulated in relapsed patients (p = 0.0194) and in patients with cancer spread to nearby lymph nodes (N+ patients) (p = 0.0396). The ROC curve analysis showed that TDV EV-miR-203a-3p was able to predict relapses with a sensitivity of 88% (AUC: 0.67; p = 0.022). Moreover, patients with high TDV EV-miR-203a-3p had a shorter time to relapse than patients with low levels (43.6 vs. 97.6 months; p = 0.00703). The multivariate analysis showed that EV-miR-203a-3p was an independent, predictive and prognostic post-surgical relapse biomarker. In conclusion, pulmonary TDV EV-miR-203a-3p is a promising new relapse biomarker for resected NSCLC patients

Monitoring HOTTIP levels on extracellular vesicles for predicting recurrence in surgical non-small cell lung cancer patients.

In resected non-small cell lung cancer (NSCLC), postsurgical recurrence is the major factor affecting long-term survival. The identification of biomarkers in extracellular vesicles (EV) obtained from serial blood samples after surgery could enhance early detection of relapse and improve NSCLC outcome. Since EV cargo contains long non-coding RNAs (lncRNAs), we aimed to analyze whether the oncogenic lncRNA HOTTIP, which higher expression in tumor tissue was related to worse outcome in NSCLC, could be detected in EV from NSCLC patients and serve as recurrence biomarker. After purification of EVs by ultracentrifugation in 52 serial samples from 18 NSCLC patients, RNA was isolated and HOTTIP was quantified by Real time PCR. We observed that patients that relapsed after surgery displayed increased postsurgical EV HOTTIP levels in comparison with presurgical levels. In the relapsed patients with several samples available between surgery and relapse, we observed an increment in the EV HOTTIP levels when approaching to relapse, which indicated its potential utility for monitoring disease recurrence. When we focused in EV HOTTIP levels in the first post-surgical sample, we observed that the detection of an increment of the expression levels in comparison to presurgical sample, predicted recurrence with high sensitivity (85.7%) and specificity (90.9%) and that patients had shorter time to relapse and shorter overall survival. In conclusion, our pilot study showed that EV HOTTIP is a potential biomarker for monitoring disease recurrence after surgery in NSCLC

NKX2-1 expression as a prognostic marker in early-stage non-small-cell lung cancer

BACKGROUND: NKX2-1, a key molecule in lung development, is highly expressed in non-small cell lung cancer (NSCLC), particularly in lung adenocarcinoma (ADK), where it is a diagnostic marker. Studies of the prognostic role of NKX2-1 in NSCLC have reported contradictory findings. Two microRNAs (miRNAs) have been associated with NKX2-1: miR-365, which targets NKX2-1; and miR-33a, which is downstream of NKX2-1. We have examined the effect of NKX2-1, miR-365 and miR-33a on survival in a cohort of early-stage NSCLC patients and in sub-groups of patients classified according to the mutational status of TP53, KRAS, and EGFR. METHODS: mRNA and miRNA expression was determined using TaqMan assays in 110 early-stage NSCLC patients. TP53, KRAS, and EGFR mutations were assessed by Sanger sequencing. RESULTS: NKX2-1 expression was upregulated in never-smokers (P = 0.017), ADK (P < 0.0001) and patients with wild-type TP53 (P = 0.001). A negative correlation between NKX2-1 and miR-365 expression was found (ρ = -0.287; P = 0.003) but there was no correlation between NKX2-1 and miR-33a expression. Overall survival (OS) was longer in patients with high expression of NKX2-1 than in those with low expression (80.8 vs 61.2 months (P = 0.035), while a trend towards longer OS was observed in patients with low miR-365 levels (P = 0.07). The impact of NKX2-1 on OS and DFS was higher in patients with neither TP53 nor KRAS mutations. Higher expression of NKX2-1 was related to higher OS (77.6 vs 54 months; P = 0.017) and DFS (74.6 vs 57.7 months; P = 0.006) compared to low expression. The association between NKX2-1 and OS and DFS was strengthened when the analysis was limited to patients with stage I disease (P = 0.005 and P=0.003 respectively). CONCLUSIONS: NKX2-1 expression impacts prognosis in early-stage NSCLC patients, particularly in those with neither TP53 nor KRAS mutations

The significance of PIWI family expression in human lung embryogenesis and non-small cell lung cancer

The expression of Piwi-interacting RNAs, small RNAs that bind to PIWI proteins, was until recently believed to be limited to germinal stem cells. We have studied the expression of PIWI genes during human lung embryogenesis and in paired tumor and normal tissue prospectively collected from 71 resected non-small-cell lung cancer patients. The mRNA expression analysis showed that PIWIL1 was highly expressed in 7-week embryos and downregulated during the subsequent weeks of development. PIWIL1 was expressed in 11 of the tumor samples but in none of the normal tissue samples. These results were validated by immunohistochemistry, showing faint cytoplasmic reactivity in the PIWIL1-positive samples. Interestingly, the patients expressing PIWIL1 had a shorter time to relapse (TTR) (p = 0.006) and overall survival (OS) (p = 0.0076) than those without PIWIL1 expression. PIWIL2 and 4 were downregulated in tumor tissue in comparison to the normal tissue (p < 0.001) and the patients with lower levels of PIWIL4 had shorter TTR (p = 0.048) and OS (p = 0.033). In the multivariate analysis, PIWIL1 expression emerged as an independent prognostic marker. Using 5-Aza-dC treatment and bisulfite sequencing, we observed that PIWIL1 expression could be regulated in part by methylation. Finally, an in silico study identified a stem-cell expression signature associated with PIWIL1 expression