Our findings suggest that lincRNA-p21 affects outcome in patients with NSCLC adenocarcinoma through the regulation of angiogenesis.

Before reaching a peripheral vein (PV), miRNAs released by the tumor are diluted and dispersed throughout the body or even retained in a specific organ. We hypothesized that blood drawn from the tumor-draining vein could provide more homogeneous information than blood drawn from the PV as that blood would contain all the biomarkers released by the tumor before they reach a potential metastatic site. We have profiled 754 miRNAs in 15 colon cancer plasma samples from the tumor-draining vein, the mesenteric vein (MV), identifying 13 microRNAs associated with relapse. The prognostic impact of these miRNAs were validated in 50 MV and 50 paired PV plasma samples of stage I-III colon cancer patients. Four miRNAs, let-7g, miR-15b, miR-155 and miR-328, were found overexpressed in MV compared to PV, and patients with high levels of those miRNAs in MV plasma had shorter time to relapse. Interestingly, in patients developing liver metastases, the exosomal cargo of miR-328 was much greater in MV than in PV plasma indicating a possible role of miR-328 in the development of liver metastases. Our results indicate that in colon cancer, the primary tumor releases high concentrations of miRNAs through the MV, and some of them are contained in tumor derived exosomes.

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.