Introduction: Non-small cell lung cancer (NSCLC) is a deadly cancer type worldwide and the main sub-type of lung cancer. Cancer susceptibility candidate-9 (CASC9) was reported to be a key player in cancer progression. However, its function and underlying mechanism in NSCLC remain unclear. Materials and Methods: Expression level of CASC9 in NSCLC tissues and cells was measured with RT-qPCR. Biological roles of CASC9 in NSCLC were analyzed with a series of in vitro experiments. Potential mechanisms of CASC9 in NSCLC were analyzed by predicting and validating the possible targets of CASC9 in NSCLC. Results: In this study, we found CASC9 expression was upregulated in NSCLC tissues and cell lines. High CASC9 expression was identified as a predictor for poorer overall survival of NSCLC patients. Furthermore, functional assays showed CASC9 knockdown suppressed NSCLC cell proliferation, migration, and invasion, while CASC9 overexpression caused opposite effects. We also found microRNA-335-3p (miR-335-3p) could act as a target of CASC9 in NSCLC and the inhibition effect of CASC9 knockdown on NSCLC progression required the activity of miR-335-3p. In addition, we identified S100 calcium-binding protein A14 (S100A14) acts as a target of miR-335-3p. Discussion: Taken together, our study suggested CASC9 could promote NSCLC progression via miR-335-3p/S100A14 axis. The CASC9/miR-335-3p/S100A14 regulatory triplets identified in this work might provide new therapeutic strategies for NSCLC treatment.

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Lung cancer is acknowledged as a common cancer with high morbidity and mortality. MicroRNAs (miRNAs), kind of non-coding single-stranded RNA molecules, can be used in cancer clinical treatments. In this research, miR-199a-5p was seen lowly expressed in NSCLC sera samples. miR-199a-5p suppressed the cell proliferation, migration and arrested cell cycle in NSCLC cell lines. The results showed that SLC2A1 (glucose transporter 1, GLUT1) was a direct target of miR-199a-5p. Downregulation of SLC2A1 could not only inhibit cell proliferation, migration and cell cycle, but also promote cell apoptosis. The data suggests that miR-199a-5p can inhibit glucose metabolism in NSCLC by targeting SLC2A1.This study proves that miR-199a-5p / SLC2A1 can play an essential role in the development of NSCLC by targeting SLC2A1. It puts forward a new approach for clinical treatments of NSCLC.

Background: Video-assisted thoracoscopic surgery (VATS) has been increasingly used in the treatment of lung cancers. But it is still unclear whether mediastinal lymph node dissection (LND) under VATS is safe and feasible. The aim of this study is to figure out whether LND by VATS is safe and feasible.Methods: Consecutive patients with primary resectable lung cancers referred for lobectomy and LND or sampling by VATS between January 2012 and December 2016 were retrospectively reviewed.Clinicopathological characteristics and perioperative results were collected for statistical analysis. Results: Seven-hundred and seventy-three VATS lobectomy patients were included in this study, 494 received LND and 279 received lymph node sampling (LNS). There were more male patients, higher pathological T and N stage in the LND group than in the LNS group. Multivariate analysis suggested that clinical N stage higher than cN0 category and LND were independent risk factors for finding pN2 diseases in all lung cancers, while higher than cN0 category, solid or micropapillary component, and LND were independently related to finding pN2 stage in adenocarcinomas. Propensity-score matching rendered 279 pairs of patients with no significant difference in age, gender, co-morbidity, tumor location, or T stage.Although the LND group had longer operation time (128 vs. 114 minutes, P<0.001), higher amount of postoperative drainage (920 vs. 720 mL, P<0.001), longer postoperative hospital stay (6 vs. 4 days, P<0.001) than the LNS group, no difference was observed in overall morbidity or mortality between the two groups. Conclusions: LND by VATS has acceptable perioperative results but can provide more accurate nodal staging compared with LNS. LND by VATS is safe, feasible, and should be recommended in patients with tumors in clinical N stages higher cN0 category or with more invasive histology.