CA9 knockdown enhanced ionizing radiation-induced ferroptosis and radiosensitivity of hypoxic glioma cells.

PURPOSE: Ferroptosis is a type of regulatory cell death, caused by excessive lipid peroxidation This study aimed to explore whether ionizing radiation could induce ferroptosis in glioma cells and whether carbonic anhydrase 9 (CA9) knockdown could enhance the killing effect of ionizing radiation on hypoxic glioma cells through ferroptosis. MATERIALS AND METHODS: The protein levels of Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4) were detected by Western blot in glioma cells irradiated by different doses of X-ray. The relative mRNA levels of ferroptosis markers and intracellular iron-associated proteins were detected by Real-time qPCR. Lipid peroxidation of glioma cells was detected by oxidation-sensitive probe C11-BODIPY581/591 staining. CCK-8 Assay was used to detect cell viability after X-ray irradiation. Cloning formation assay was used to assess the radiosensitivity of glioma cells. The exposure of cell surface calreticulin was measured by immunofluorescence staining. RESULTS: X-ray induced lipid peroxidation and ferroptosis markers expression in U251 and GL261 glioma cells. Knockdown of CA9 in hypoxic glioma cells significantly altered the expression of iron regulation-related proteins and enhanced X-ray-induced ferroptosis and radiosensitivity. The ferroptosis inhibitor significantly improved the survival of cells irradiated by X-ray, while ferroptosis inducers (FINs) enhanced the lethal effect of X-ray on cells. Enhancing ferroptosis in glioma cells promoted the exposure and release of damage-associated molecular patterns (DAMPs). CONCLUSIONS: Ionizing radiation can induce ferroptosis in glioma cells. CA9 knockdown can enhance the radiosensitivity of hypoxic glioma cells and overcome the resistance of ferroptosis under hypoxia. Enhancing ferroptosis will become a new idea to improve the efficacy of radiotherapy for glioma.

Tumor-associated macrophages promote the metastasis and growth of non-small-cell lung cancer cells through NF-κB/PP2Ac-positive feedback loop.

Non-small-cell lung cancer (NSCLC), with its aggressive biological behavior, is one of the most diagnosed cancers. Tumor-associated inflammatory cells play important roles in the interaction between chronic inflammation and lung cancer, however the mechanisms involved are far from defined. In the present study, by developing an orthotopic NSCLC mouse model based on chronic inflammation, we proved that an inflammatory microenvironment accelerated the growth of orthotopic xenografts in vivo. Tumor-associated macrophages, the most abundant population of inflammatory cells, were identified. Treatment with macrophage-conditioned medium (MCM) promoted the growth and migration of NSCLC cells. Using bioinformatics analysis, we identified downregulated PP2Ac expression in NSCLC cells upon treatment with MCM. We further confirmed that this downregulation was executed in an NF-κB pathway-dependent manner. As IκB kinase (IKK) has been proved to be a substrate of PP2Ac, inhibition on PP2Ac could result in amplification of NF-κB pathway signaling. Overexpression of PP2Ac, or the dominant-negative forms of IKK or IκB, attenuated the acceleration of growth and metastasis by MCM. Using bioinformatics analysis, we further identified that CXCL1 and COL6A1 could be downstream of NF-κB/PP2Ac pathway. Luciferase assay and ChIP assay further confirmed the location of response elements on the promoter regions of CXCL1 and COL6A1. Elevated CXCL1 facilitated angiogenesis, whereas upregulated COL6A1 promoted proliferation and migration.

[Corrigendum] Repression of Smad4 by miR­205 moderates TGF­ß-induced epithelial­mesenchymal transition in A549 cell lines.

Following the publication of this article, an interested reader drew to the authors' attention that, in Fig. 6B on p. 706, various of the data panels appeared to show overlapping data. After having carefully re­examined the manuscript, raw data and laboratory records, the authors were able to identify the correct data for the figure concerned. Essentially, some of the data panels in Fig. 6 had been erroneously selected from photographs taken of the same data, but with different fields of view. In addition, the authors repeated some of the contentious experiments and obtained similar results, thereby corroborating the results and conclusions reported in this study. Therefore, the errors made with the assembly of Fig. 6 did not have an adverse bearing on the overall conclusions reported in the study. A revised version of Fig. 6, presenting the correct data for Fig. 6B, is shown on the next page. The authors are grateful to the Editor of International Journal of Oncology for allowing them the opportunity to publish this Corrigendum, and all of the authors agree to the publication of this Corrigendum. The authors sincerely apologize for this mistake, and apologize to the readership of the Journal for any inconvenience caused. [the original article was published in International Journal of Oncology 49: 700­708, 2016; DOI: 10.3892/ijo.2016.3547].

Low Expression of DDX60 Gene Might Associate with the Radiosensitivity for Patients with Breast Cancer.

DEXD/H box helicase 60 (DDX60) is a new type of DEAD-box RNA helicase, which is induced to express after virus infection. It might involve in antiviral immunity by promoting RIG-I-like receptor-mediated signal transduction. In addition, previous studies had shown that the expression of DDX60 is related to cancer, but there was still a lack of relevant research in breast cancer. In this study, we used the information of patients with breast cancer in the TCGA database for statistical analysis and found that the breast cancer patients with low expression of DDX60 exhibited radiosensitivity. Comparing the radiotherapy groups with the nonradiotherapy groups, for patients with low expression of DDX60, the adjusted hazard ratio (HR) values for radiotherapy were 0.244 (0.064-0.921) and 0.199 (0.062-0.646) in the training and validation datasets, with the p values 0.040 and 0.007, respectively. However, for patients with high expression of DDX60, the adjusted hazard ratio (HR) values were 3.582 (0.627-20.467) and 2.421 (0.460-12.773), with the p values 0.054 and 0.297, respectively. These results suggested that the expression of DDX60 might strongly associate with individualized radiosensitivity in patients with breast cancer.

Low Expression of GLIS2 Gene Might Associate with Radiosensitivity of Gastric Cancer.

Human gene GLIS family zinc finger 2 (GLIS2) is a member of GLI-similar zinc finger protein family. Previous studies indicated GLIS2 gene involved in tumorigenesis mechanisms. However, the association between GLIS2 expression and radiosensitivity of gastric cancer has not been well understood. In this study, we used the gastric cancer database in TCGA, and significant association was observed between the low expression of GLIS2 and radiosensitivity of patients with gastric cancer. The adjusted HR values for radiotherapy were 0.162(0.035-0.756) and 0.089(0.014-0.564), with p values 0.021 and 0.010, respectively, in training and testing data, for these patients with low expression of GLIS2, while for patients with high expression of GLIS2, there was no significant survival difference between radiotherapy and nonradiotherapy groups. The adjusted HR were 0.676(0.288-1.586) and 0.508(0.178-1.450), with p values 0.368 and 0.206 in training and testing data, respectively. Further study showed that, for low expression patients, radiotherapy did not significantly increase new tumor event rate and disease progression rate, which partially supported our assumption. These results suggested that low expression of GLIS2 might significantly associate with the radiosensitivity of patients with gastric cancer. The GLIS2 gene might be a potential effective molecular marker of gastric cancer for precise radiotherapy.

The regulation of Neuropilin 1 expression by miR-338-3p promotes non-small cell lung cancer via changes in EGFR signaling.

Neuropilin 1 (NRP1) is a transmembrane glycoprotein that acts as a co-receptor for multiple extracellular ligands and typically performs growth-promoting functions in cancer cells. Accumulating evidence indicates that NRP1 is upregulated, and may be an independent predictor of cancer relapse and poor survival, in many cancer types, including non-small cell lung cancer (NSCLC). Recent evidence suggests that NRP1 affects tumour cell viability via the epidermal growth factor receptor (EGFR) and Erb-B2 receptor tyrosine kinase 2 (ErbB2) signalling pathways in venous endothelial cells and in multiple cancer cells. In the present study, we aimed to evaluate the role of NRP1 in NSCLC tumourigenesis and to explore a new post-transcriptional mechanism of NRP1 regulation via a microRNA that mediates EGFR signalling regulation in lung carcinogenesis. The results showed that miR-338-3p is poorly expressed and NRP1 is overexpressed in NSCLC tissues relative to their levels in adjacent noncancerous tissues. Luciferase reporter assays, quantitative real-time reverse transcription PCR, and Western blot analyses showed that NRP1 is a direct target of miR-338-3p. Overexpression of miR-338-3p in NSCLC cell lines inhibited cell proliferation in vitro and in vivo. Moreover, cell migration and invasion were inhibited by miR-338-3p overexpression. These effects occurred via the EGF signalling pathway. Our data revealed a new post-transcriptional mechanism by which miR-338-3p directly targets NRP1; this mechanism plays a role in enhancing drug sensitivity in EGFR wild-type patients with NSCLC.

Prognostic evaluation of patients with resectable lung cancer using systemic inflammatory response parameters.

Lung cancer is one of the leading causes of cancer-associated mortality. C-reactive protein (CRP), albumin (ALB), globulin (GLB), lactate dehydrogenase (LDH), neutrophil-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been identified as general parameters for systemic inflammatory response (SIR). Furthermore, these parameters are also associated with tumor development and metastasis. The present study aimed to investigate the predictive values of these SIR parameters in patients with resectable lung cancer. In total, 101 patients with resectable lung cancer were recruited in the present study. The patients were divided into two groups according to the median value of pre-treatment CRP, ALB, GLB, LDH, NLR or PLR values. The post-/pre-treatment ratios were defined as the ratio of pre-treatment blood parameter values and the corresponding values obtained following therapy. A ratio of ≤1.1 indicated that the values were not increased, while a ratio of >1.1 suggested that the values were increased following treatment. Patients with lower pre-treatment ALB levels had poorer overall survival (OS) rates, whereas GLB, LDH, CRP, NLR or PLR levels were not associated with outcomes. Whole course treatment (surgery combined with adjuvant chemotherapy) significantly increased the value of ALB, but decreased the value of NLR, whereas it had no effect on the values of LDH, CRP or PLR. Post-/pre-treatment LDH and PLR were associated with outcomes. Post-/pre-treatment ALB, GLB, CRP and NLR were not associated with outcomes. Multivariate analysis revealed that a low pre-treatment ALB level and increased post-/pre-treatment PLR were independent risk factors affecting OS. The receiver operating characteristic curve analysis demonstrated that an ALB value of 47.850 g/l was considered to be the optimal cut-off value for prognosis; the sensitivity was 28.8% and specificity was 95.9%. It was suggested that the pre-treatment ALB and post-/pre-treatment PLR may be potential prognostic factors in resectable lung cancer.

The nuclear transcription factor RelB functions as an oncogene in human lung adenocarcinoma SPC-A1 cells.

BACKGROUND: Lung cancer is a leading public health issue worldwide. Although therapeutic approaches have improved drastically in the last decades, the prognosis of lung cancer patients remains suboptimal. The canonical nuclear transcription factor kappa B (NF-κB) signalling pathway is critical in the carcinogenesis of lung cancer. The non-canonical NF-κB signalling pathway (represented by RelB) has attracted increasing attention in the pathogenesis of haematological and epithelial malignancies. However, the function of RelB in non-small cell lung cancer (NSCLC) is still unclear. Recently, high expression of RelB has been detected in NSCLC tissues. We have also demonstrated that RelB expression is an independent prognostic factor in NSCLC patients. METHODS: The mRNA and protein expression of RelB in NSCLC tissues were detected by qRT-PCR and IHC assay. The cell growth of SPC-A1 cells was detected in real-time using the x-Celligence system and xenograft tumour assays. The proliferation capability of cells was detected using a CFSE assay. Cell apoptosis was measured using Annexin V/PI staining, cell cycle was analyzed by the cytometry. Cell migration abilities were detected using the x-Celligence system and wound healing assays. The relative amounts of the active and inactive gelatinases MMP-2 and MMP-9 were examined using gelatin zymography experiments. Apoptosis of RelB depletion SPC-A1 cells after ionizing radiation at 8 Gy. The expression of cellular proliferation signal pathway related-proteins were examined by Western blot analysis. RESULTS: The expression of RelB increases in NSCLC tissues. High RelB expression was significantly correlated with advanced-metastatic stage in patients with NSCLC. RelB-silencing inhibits cell growth in vitro and in vivo. We found that RelB affected cell proliferation by regulating AKT phosphorylation. RelB silencing attenuates the migration and invasion abilities of SPC-A1 cells and is likely related to the down regulation of MMP-9 activity and Integrin ß-1 expression. In addition, RelB modulated radiation-induced survival of NSCLC cells predominantly by regulating Bcl-xL expression. CONCLUSIONS: Given the involvement of RelB in cell proliferation, migration, invasion, and radio-resistance, RelB functions as an oncogene in NSCLC cells. Our data here shed light on unexplored aspects of RelB in NSCLC.

Developing a radiosensitivity gene signature for Caucasian patients with breast cancer.

Adjuvant radiotherapy is an important clinical treatment option for patients with breast cancer. However, for Caucasian patients, the clinical benefit of adjuvant radiotherapy can differ from African­American patients with respect to the overall survival. The goal of the current study was to develop a gene signature and to pre­identify patients likely to benefit from radiotherapy. Using publicly available breast cancer data from The Cancer Genome Atlas, a new cross­validation procedure was proposed for developing a gene signature and predicting radiosensitive patients. The results demonstrated that the predicted radiosensitive patients who received radiotherapy exhibited a significantly better survival, while the effect of radiotherapy was not significant for predicted non­radiosensitive patients. Further hierarchical cluster analysis revealed that the predicted sensitivity for each patient corresponded closely to the results of the cluster analysis. Collectively, the findings of the current study demonstrated that a radiosensitive molecular signature can be used to identify radiosensitive Caucasian patients with breast cancer.

Methylated +322-327 CpG site decreases hOGG1 mRNA expression in non-small cell lung cancer.

hOGG1 plays a role in several disease pathways, including various cancers. Despite such functional importance, how hOGG1 is regulated at the transcriptional level in human non-small cell lung cancer (NSCLC) remains unknown, particularly via DNA methylation changes. We obtained NSCLC tissues and adjacent non-cancerous tissues and examined hOGG1 mRNA expression levels. NSCLC cells were treated with 5-Aza to test whether DNA methylation can influence the expression of hOGG1. The MassARRAY EpiTYPER and luciferase reporter gene assays were used to define the functional region of the hOGG1 gene (including CpG sites). Finally, ChIP assay was utilized to verify transcription factor binding to the hOGG1 5'-UTR region. Our previous studies supported the idea that the methylation of the hOGG1 gene promoter region occurs frequently in NSCLC. Treatment with 5-Aza, a demethylating agent, led to a significant restoration of hOGG1 expression in NSCLC cell lines. Quantitative PCR and MassARRAY EpiTYPER assays demonstrated that methylation of the +322-327 CpG site in the 5'-UTR region of hOGG1 was higher in NSCLC tissues compared with adjacent non-cancerous tissues. Notably, the methylation level of +322-327 site (T/N) was inversely correlated with that of hOGG1 mRNA level (T/N) in 25 NSCLC tissues. ChIP assay and in silico prediction showed an association between the +322-327 CpG site and Sp1, which has been reported to be an activator of transcription. Importantly, luciferase reporter gene and ChIP assays showed that +322-327 CpG site methylation particularly reduced the recruitment of Sp1 to the 5'-UTR sequence in hOGG1 and reduced transcriptional activity ~50%. In summary, we have demonstrated that hOGG1 mRNA is downregulated in NSCLC tissues. Moreover, we identified that the methylated +322-327 CpG site in the hOGG1 5'-UTR is associated with reduced expression of hOGG1 by decreasing the recruitment of Sp1 to the 5'-UTR of hOGG1.

MicroRNA-205 targets SMAD4 in non-small cell lung cancer and promotes lung cancer cell growth in vitro and in vivo.

Despite advances in diagnosis and treatment, the survival of non-small cell lung cancer (NSCLC) patients remains poor; therefore, improved understanding of the disease mechanism and novel treatment strategies are needed. Downregulation of SMAD4 and dysregulated expression of miR-205 have been reported. However, the relationship between them remains unclear. We investigated the effect of microRNA (miR)-205 on the expression of SMAD4 in NSCLC. Knockdown and overexpression of SMAD4 promoted or suppressed cellular viability and proliferation, and accelerated or inhibited the cell cycle in NSCLC cells, respectively. The 3'-untranslated region (3'-UTR) of SMAD4 was predicted as a target of miR-205. Luciferase assays validated that miR-205 binds directly to the SMAD4 3'-UTR. Protein and mRNA expression analyses confirmed that miR-205 overexpression in NSCLC cells inhibited the expression of SMAD4 mRNA and protein. In human NSCLC tissues, increased miR-205 expression was observed frequently and was inversely correlated with decreased SMAD4 expression. Ectopic expression of miR-205 in NSCLC cells suppressed cellular viability and proliferation, accelerated the cell cycle, and promoted tumor growth of lung carcinoma xenografts in nude mice. Our study showed that miR-205 decreased SMAD4 expression, thus promoting NSCLC cell growth. Our findings highlighted the therapeutic potential of targeting miR-205 in NSCLC treatment.

CD73/NT5E is a target of miR-30a-5p and plays an important role in the pathogenesis of non-small cell lung cancer.

BACKGROUND: CD73 (ecto-5'-nucleotidase) is implicated in the development of many types of cancer. CD73 inhibitors are currently being tested in clinical trials for the treatment of cancer. Understanding the molecular and cellular actions of CD73 inhibitors is the key to improving this line of therapy. METHODS: Quantitative real-time PCR (qRT-PCR) was used to detect the expression of CD73 and miR-30a-5p; Western blot and immunohistochemical assays were used to investigate the levels of CD73 and other proteins. Flow cytometry was used to determine cell cycle stage and apoptosis. CCK-8 and clonogenic assays were used to investigate cell proliferation. Wound healing, migration and invasion assays were used to investigate the motility of cells. A lung carcinoma xenograft mouse model was used to investigate the in vivo effects of CD73 and miR-30a-5p. RESULTS: In the present study, we found that CD73 is overexpressed and miR-30a-5p is underexpressed in non-small cell lung cancer tissues compared with adjacent noncancerous. Further, we showed that CD73 is a direct target of miR-30a-5p by luciferase reporter assays, qRT-PCR and western blot analysis. We also found that overexpression of miR-30a-5p in these non-small cell lung cancer cell lines inhibited cell proliferation in vitro and in vivo. Moreover, the epithelial-to-mesenchymal phenotype was suppressed and cell migration and invasion were inhibited; these effects were brought about via the EGF signaling pathway. CONCLUSIONS: Our findings reveal a new post-transcriptional mechanism of CD73 regulation via miR-30a-5p and EGFR-related drug resistance in non-small cell lung cancer.

Aberrant promoter methylation of hOGG1 may be associated with increased risk of non-small cell lung cancer.

DNA methylation may epigenetically inactivate tumor suppressor genes in NSCLC. As the human 8-oxoguanine DNA glycosylase (hOGG1) gene promoter is frequently methylated in NSCLC, we evaluated whether genetic or epigenetic alterations of hOGG1 are associated with increased risk of non-small cell lung cancer. Three hOGG1 haplotype-tagging SNPs (htSNP) were genotyped in PCR-restriction fragment length polymorphism assays, and one htSNP was genotyped in a PCR-single-strand conformation polymorphism assay in case-control studies of 217 NSCLC patients and 226 healthy controls. The methylation profiles of peripheral blood mononuclear cell specimens from 121 NSCLC patients and 121 controls were determined through methylation-specific PCR of hOGG1. No differences in allele or genotype frequencies between NSCLC patients and controls were observed at any of the four polymorphic sites (rs159153, rs125701, rs1052133, and rs293795). However, hOGG1 methylation-positive carriers had a 2.25-fold greater risk of developing NSCLC (adjusted odds ratio: 2.247; 95% confidence interval: 1.067-4.734; P = 0.03) than methylation-free subjects. Furthermore, the demethylating agent 5-aza-2'-deoxycytidine restored hOGG1 expression in NSCLC cell lines. These data provide strong evidence of an association between peripheral blood mononuclear cell hOGG1 methylation and the risk of NSCLC in a Chinese population.

Prognostic significance of RelB overexpression in non-small cell lung cancer patients.

BACKGROUND: Lung cancer is a major public health issue in most countries, including China. The expression of RelB is associated with poor prognosis in diverse cancers. However, whether RelB expression could be an indicator of poor prognosis in non-small cell lung cancer (NSCLC) is still unclear. METHODS: The expression of RelB in NSCLC tumor tissue and adjacent non-neoplastic tissues were examined by immunohistochemistry. Chi-square or two-tailed Fisher's exact tests were used to analyze possible associations between qualitative clinicopathological variables and RelB expression. Kaplan-Meier analysis and a Cox regression model were employed to determine independent prognostic factors. RESULTS: The expression of RelB was increased in tumor tissue compared with adjacent non-neoplastic tissue in NSCLC patients. High RelB expression was significantly correlated with degree of differentiation (P = 0.023), depth of tumor invasion (P < 0.001), lymph node metastasis (P = 0.017), distant metastases (P = 0.004), and tumor node metastasis stage (P < 0.001) in patients with NSCLC. NSCLC patients with high RelB expression had significantly shorter overall survival than those with low RelB expression (P < 0.001). Our results indicate that high RelB expression is an independent prognostic factor for patients with NSCLC (P < 0.001). CONCLUSIONS: High RelB expression could provide a basis for judgment of prognosis in patients with NSCLC.

Repression of Smad4 by miR­205 moderates TGF-ß-induced epithelial-mesenchymal transition in A549 cell lines.

The TGF-ß/Smad signaling pathway plays important roles in cancer cell proliferation, apoptosis, differentiation, angiogenesis and epithelial-mesenchymal transition (EMT), which is the key event in the early stages of cancer metastasis and enhances the capability of cell migration and invasion. Smad4 acts as the only Co-Smad of TGF/Smad signaling pathway and plays the key role in TGF-ß-mediated EMT. Nevertheless, the mRNA regulation mechanisms of Smad4 in human non-small cell lung cancer (NSCLC) remains largely unclear. Computational algorithms predicted that the 3'-UTR of Smad4 is a target of miR­205. Here, we validated that miR­205 could directly bind to 3'-UTR of Smad4 by luciferase assays. Moreover, we investigated the functional roles of miR­205 and its molecular link to Smad4 in lung cancer cells. In this study, we confirmed that overexpression of miR­205 suppressed the expression of Smad4, in turn, weakened the TGF-ß/Smad signaling pathway and inhibited TGF-ß/Smad4-induced EMT, invasion and migration ultimately. Furthermore, this study shows that miR­205 can serve as a promising therapeutic target of highly aggressive NSCLC.

Expression profile analysis of microRNAs and downregulated miR-486-5p and miR-30a-5p in non-small cell lung cancer.

Lung cancer is the leading cause of cancer-related mortality worldwide and although there have been improvements in treatment there is a low survival rate. The aim of the present study was to investigate the effect of microRNA (miRNA) on cell pathways. A miRNA microarray was used to profile miRNAs of lung cancer tissues. It was identified that 33 miRNAs with >2.0-fold change and FDR <0.05 were differentially expressed between the adjacent non-cancerous lung tissues and non-small cell lung cancers NSCLCs (P<0.005). The data were optimized in combination with physical interaction analysis to obtain crucial miRNAs. The results showed that differentially expressed miRNAs were associated with biological processes such as cell migration, protein phosphorylation and neuron differentiation, and signaling pathways such as MAPK, TGF-ß and PI3K/Akt signaling pathways. Validation of significant miRNAs in independent 40 paired NSCLC tissues demonstrated that the expression level of miR-486-5p and miR-30a-5p was significantly downregulated in another 40 paired lung cancer tissues. Taken together, the results provided strong evidence of the possible involvement of miRNAs in the development and progression of NSCLC. Thus, the results are of importance for clinical investigators and for those who design miRNA­based novel cancer therapeutics.