circSNX6 (hsa_circ_0031608) enhances drug resistance of non-small cell lung cancer (NSCLC) via miR-137.

circRNAs have been suggested to modulate NSCLC tumorigenesis and drug resistance. Whether circSNX6 affects NSCLC remains unclear. In this study, we aim to investigate the role of circSNX6 in drug resistance of NSCLC exposed to cisplatin. RT-qPCR method was used to investigate expression levels of circSNX6, miR-137 and CXCL12. MTT, cell colony formation and TUNEL assays were utilized to assess cell viability, proliferation, apoptosis, respectively. Xenograft assay was conducted to examinein vivotumor growth. circSNX6 overexpression caused enhanced cell viability and proliferation of H1299 and Calu-1, while it inhibited apoptosis under cisplatin treatment. miR-137 inhibitor greatly rescued cell viability, proliferation and apoptosis of circSNX6 knockdown H1299 cells. miR-137 mimic increased ROS generation, as well as reduced GSH and SOD levels, whereas miR-137 inhibitor exerted opposing effect. circSNX6 knockdown also enhanced ROS generation, as well as decreased GSH and SOD levels. CXCL12 partially restored miR-137 mimic-modulated cell viability, proliferation and apoptosis. Herein, our group proposes circSNX6 as key regulator for drug resistance of NSCLC. The findings provide solid groundings for understanding of NSCLC pathogenesis and development of therapeutics.

MicroRNA-related single-nucleotide polymorphism of XPO5 is strongly correlated with the prognosis and chemotherapy response in advanced non-small-cell lung cancer patients.

This study was performed to investigate if the microRNA-related single-nucleotide polymorphisms (miR-SNPs) of XPO5 gene predicted the prognosis and pathological features of advanced non-small-cell lung cancer patients receiving chemotherapy. A total of 131 advanced non-small-cell lung cancer (NSCLC) patients were recruited. MicroRNA (miRNA) binding site prediction software was adopted for the prediction and screening of SNPs in XPO5 and miRNA binding regions. Polymerase chain reaction (PCR) amplification was further performed. Time-dependent survival-free curves were constructed using the Kaplan-Meier technique. Univariate and the multivariate survival analyses were conducted for confirmation of prognostic factor for advanced NSCLC patients receiving chemotherapy. There were no significant differences of SNP distribution frequencies between groups, without statistical significance (P > 0.05). Included clinical pathological features and chemotherapy regimens showed no apparent statistical significance in influencing the curative effect of chemotherapy in advanced NSCLC patients (all P > 0.05). While the objective response rate (ORR) in patients who carried AA and AC genotype was 35.48 and 51.22 %, respectively, with statistically significant difference (P < 0.05). Univariate survival analysis indicated that patients who carried AA genotype showed a significantly lower 5-year survival rate to those who carried AC genotype (P < 0.05). And, considering pathological features, statistical significance was found in patients with different pathological types, lymph node metastasis, differentiation degree, T staging, and pathological staging (all P < 0.05). Multivariate analysis results indicated that the SNP sites of rs11077 might be an independent prognostic factor of advanced NSCLC patients receiving chemotherapy (risk ratio [RR] = 0.346; 95 % confidence interval [95 % CI] = 0.174-0.685, P = 0.002). Other clinical features were all considered to have no apparent effect in influencing the prognostic outcomes of advanced NSCLC patients receiving chemotherapy except lymph node metastasis (P < 0.05). miR-SNP rs11077 of XPO5 may be independently connected with the prognosis and chemotherapy response of advanced NSCLC patients, and patients with AC genotype have relatively improved prognostic outcomes and better curative effect of chemotherapy than those with AA allele of XPO5. Further, lymph node metastasis may be also involved in influencing the prognosis of advanced NSCLC patients.

Matrix metalloproteinase activity in early-stage lung cancer.

BACKGROUND: The matrix metalloproteinases (MMPs)-2, -9 and -7 are thought to be associated with tumor invasion, metastasis, and angiogenesis. However, their possible roles in early-stage lung cancer are not clear. We measured the activity of MMP-2, -7 and -9 in early-stage lung cancer tissues. MATERIAL AND METHODS: Normal lung tissues and cancer tissues were collected from 60 consecutive stage-I non-small cell lung cancer (NSCLC) patients. The activities of MMP-2 and MMP-9 were determined by gelatin zymography, and the activity of MMP-7 was determined by casein zymography. Furthermore, the ratio of the active form of MMP-2 in tumor tissue (T) compared with normal tissue (N) was determined, and the survival in the groups with different MMP-2 T:N ratio was compared. RESULTS: The activity of both MMP-2 and MMP-9 was detected in all cancer and normal tissues. Interestingly, MMP-9 activity was significantly reduced, whereas MMP-2 activity was significantly increased, in cancer tissues compared to normal tissues. The survival rate of the MMP-2 T:N ratio > 2.5 group was 57.45%, which was significantly reduced compared with that of the T:N ratio ≤ 2.5 group (86.78%). CONCLUSION: Our findings suggest that MMP-2, but not MMP-9 and MMP-7, may be implicated in early-stage tumor invasion, metastasis, and angiogenesis in NSCLC.

TBX18 knockdown sensitizes esophageal squamous cell carcinoma to radiotherapy by blocking the CHN1/RhoA axis.

OBJECTIVE: Radioresistance is a challenge in the effective treatment of esophageal squamous cell carcinoma (ESCC). Herein, this research ascertained whether TBX18 reduced the radiosensitivity of ESCC. METHODS: Bioinformatics analysis was utilized to retrieve differentially expressed genes. Then, the expression of corresponding candidate genes was tested using qRT-PCR in ESCC clinical specimens, and TBX18 was selected for subsequent experiments. The binding between TBX18 and CHN1 was evaluated by dual-luciferase reporter and ChIP assays, and the relationship between CHN1 and RhoA was identified by GST pull-down. Ectopic expression or knockdown experiments and radiation treatment were performed in cells and the nude mouse xenograft model to clarify the impacts of TBX18, CHN1, and RhoA on radiosensitivity in ESCC. RESULTS: Bioinformatics analysis and qRT-PCR retrieved upregulated TBX18 in ESCC for the follow-up study. Additionally, TBX18 was positively correlated with CHN1 in ESCC clinical specimens. Mechanistically, TBX18 bound to the CHN1 promoter region to transcriptionally activate CHN1, thus elevating RhoA activity. Moreover, TBX18 knockdown reduced ESCC cell proliferation and migration while augmenting their apoptosis after radiation, which was negated by further overexpressing CHN1 or RhoA. CHN1 or RhoA knockdown diminished ESCC cell proliferation and migration, as well as enhanced cell apoptosis, subsequent to radiation. Likewise, TBX18 overexpression increased ESCC cell autophagy after radiation, which was partially reversed by knockdown of RhoA. The results of in vivo xenograft experiments in nude mice were concurrent with the in vitro results. CONCLUSION: TBX18 knockdown lowered CHN1 transcription and thus reduced RhoA activity, which sensitized ESCC cells to radiotherapy.

Novel Au-Se Nanoprobes for Specific Thrombin Detection in Diagnosis of Lung Cancer.

Thrombin is associated with malignant tumors and promotes tumor development, metastasis, and angiogenesis, therefore its identification especially in lung cancer cells is crucial. Because the interference of in vivo biothiols caused false positive findings with prior gold fluorescent nanoprobes, in this manuscript, an Au-selenol(Se) nanoprobe (5-FAM-peptide-Se-AuNPs) that could specifically detect thrombin was designed and compared to traditional Au-S nanoprobes. For reaching this goal, fluorophore-bearing thrombin-specific peptide containing selenol at the end was synthesized. The nanoprobe may be broken by thrombin to regain its fluorescence in lung cancer cells, allowing for high-sensitivity thrombin detection. Since the Au-Se bond is more stable than the Au-S bond, the accuracy of the detection results can be guaranteed. The probe synthesis method is simple and cost-effective, as well as having high biocompatibility. Low concentrations of thrombin can be detected and imaged in lung cancer cells. The synthetic method of this probe opens up new avenues for the application of Au-Se bonds.

Eight-gene signature predicts recurrence in lung adenocarcinoma.

BACKGROUND: Recurrence significantly influences the survival in patients with lung adenocarcinoma (LUAD). However, there are less gene signatures that predict recurrence risk of LUAD. OBJECTIVE: We performed this study to construct a model to predict risk of recurrence in LUAD. METHODS: RNA-seq data from 426 patients with LUAD were downloaded from The Cancer Genome Atlas (TCGA) and were randomly assigned into the training (n= 213) and validation set (n= 213). Differentially expressed genes (DEGs) between recurrent and non-recurrent tumors in the training set were identified. Recurrence-associated DEGs were selected using multivariate Cox regression analysis. The recurrence risk model that identifies patients at low and high risk for recurrence was constructed, followed by the validation of its performance in the validation set and a microarray dataset. RESULTS: In total, 378 DEGs, including 20 recurrence-associated DEGs, were identified between the recurrent and non-recurrent tumors in the training set. The signatures of 8 genes (including AZGP1, INPP5J, MYBPH, SPIB, GUCA2A, HTR1B, SLC15A1 and TNFSF11) were used to construct the prognostic model to assess the risk of recurrence. This model indicated that patients with high risk scores had shorter recurrence-free survival time compared with patients with low risk scores. ROC curve analysis of this model showed it had high predictive accuracy (AUC > 0.8) to predict LUAD recurrence in the TCGA cohort (the training and validation sets) and GSE50081 dataset. This prognostic model showed high predictive power and performance in predicting recurrence in LUAD. CONCLUSION: We concluded that this model might be of great value for evaluating the risk of recurrence of LUAD in clinics.