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The Nemo‑like kinase (NLK), a conserved serine/threonine kinase, plays a critical role in the regulation of a variety of transcription factors, with important roles in determining cell fate. Although recent studies have demonstrated decreased expression patterns of NLK in various types of human cancer, the functional mechanism of NLK in cancer development has not been elucidated. Here, in the present study overexpression of NLK was found to inhibit the growth and migration of the non‑small cell lung cancer A549 cell line. NLK was subsequently found to interact with 14‑3‑3ζ (also known as YWHAZ), which is responsible for E‑cadherin silencing during epithelial‑mesenchymal transition (EMT). Furthermore, NLK overexpression was able to restore the expression of E‑cadherin inhibited by 14‑3‑3ζ. Notably, NLK interacts with 14‑3‑3ζ and prevents its dimerization, which is essential for 14‑3‑3ζ stability and function. By fusing two copies of the 14‑3‑3ζ gene, via a Gly‑rich linker, a non‑dissociable dimer of 14‑3‑3ζ was formed. It was found that NLK was unable to restore the expression of E‑cadherin inhibited by the overexpression of the fused dimer of 14‑3‑3ζ. In addition, the increased ability of migration induced by the overexpression of fused 14‑3‑3ζ dimer could not be altered by NLK overexpression. The results from the present study indicate that NLK is a negative regulator of 14‑3‑3ζ and plays a tumor suppressive role in the inhibition of cancer cell migration.

Growth arrest-specific transcript 5 (GAS5) has been demonstrated to correlate with clinicopathological characteristics and serve as a tumor suppressor in non-small cell lung cancer (NSCLC). However, the underlying mechanism of the competing endogenous RNA (ceRNA) regulatory network involving GAS5 in NSCLC remains to be elucidated. In this study, qRT-PCR results showed that GAS5 was downregulated and miR-135b was upregulated in NSCLC tissues and cells. The expressions of GAS5 and miR-135b changed inversely in response to irradiation. Gain-of-function experiments revealed that GAS5 overexpression and miR-135b downregulation significantly suppressed tumorigenesis by repressing cell proliferation and invasion, and enhanced the radiosensitivity of NSCLC cells by reducing colony formation rates. Luciferase reporter assay confirmed that GAS5 could directly target miR-135b and negatively regulate its expression. Moreover, rescue experiments demonstrated that miR-135b upregulation markedly abolished GAS5 overexpression-induced tumorigenesis inhibition and radiosensitivity improvement. Furthermore, xenograft model analysis validated that GAS5 overexpression suppressed tumor growth and improved radiosensitivity of NSCLC cells in vivo. Taken together, GAS5 inhibits tumorigenesis and enhances radiosensitivity by suppressing miR-135b expression in NSCLC cells, deepening our understanding of the mechanism of miRNA-lncRNA interaction and providing a novel therapeutic strategy for NSCLC.

Transforming growth factor-activated kinase 1 (TAK1)-binding protein 3 (TAB3) is essential for the activation of the nuclear factor kappa B (NF-κB) pathway and has important roles in cell survival. However, the contribution of TAB3 to non-small cell lung cancer (NSCLC) remains elusive. In the present study, Western blotting and immunohistochemistry assays demonstrated that TAB3 expression was frequently increased in NSCLC tissues and cells. In addition, chi-square test and Kaplan-Meier analysis revealed that upregulation of TAB3 expression correlated with a more invasive tumor phenotype and poor prognosis. In addition, a series of experiments, including serum starvation-refeeding experiment and TAB3-siRNA transfection assay, showed that TAB3 expression promoted NSCLC cell proliferation. Furthermore, the effect of TAB3 expression on the sensitivity to cis-diamminedichloroplatinum (CDDP) and possible signaling transduction pathways was investigated. When the expression of TAB3 was inhibited by siRNA transfection, the sensitivity to CDDP was enhanced. Moreover, it showed that downregulation of TAB3 enhanced CDDP-induced A549 cell apoptosis through the inhibition of the NF-κB pathway. These results suggest that TAB3 plays a critical role in NSCLC progression and chemoresistance and that TAB3 depletion may be a promising approach to lung cancer therapy.

ILF2 (NF45) is a sequence-specific DNA binding protein that is involved in mitosis control, transcriptional regulation, DNA breaks repair, microRNA processing and viral replication. In the present study, we aim to investigate the potential role of ILF2 in the progression of non-small cell lung cancer (NSCLC). Western blot analysis indicated that ILF2 was up-regulated in NSCLC tissues, compared with adjacent non-tumorous ones. Furthermore, immunohistochemistry analysis showed that the expression of ILF2 was correlated with histological differentiation, clinical stage and Ki-67 expression in NSCLC specimens. In addition, using Kaplan-Meier survival analysis, we found that high expression of ILF2 predicted poor outcome in NSCLC patients. Furthermore, we showed that up-regulated expression of ILF2 might play a regulatory role in the proliferation of NSCLC cells using serum starvation and release assay. Moreover, knockdown of ILF2 inhibited cell proliferation and cell cycle progress of NSCLC cells. In conclusion, our results indicated that ILF2 was involved in the pathogenesis of NSCLC and might be a potential target for NSCLC therapy.

p29, also known as SYF2/fSAP29/NTC31, is a protein associated with chromatin and involved in DNA damage response, cell cycle arrest and pre-mRNA splicing. In p29-depleted cells, DNA replication was reduced and cell population in G1 phase increased. In this study, we investigated the potential role of p29 in the regulation of non-small cell lung cancer (NSCLC) progression. Western blot and immunohistochemistry staining showed that p29 was up-regulated in clinical NSCLC tissues compared with adjacent non-cancerous tissues, and the expression of p29 had a positive correlation with clinical stage and histological differentiation, as well as expression of Ki-67, a proliferating marker. Kaplan-Meier analysis indicated that patients with high level of p29 expression had poor overall survival. In addition, small interfering RNA of p29 was performed, and the effects on NSCLC growth were examined. Interference of p29 blocked S phase entry, inhibited proliferation of A549 cells and up-regulated level of p21 expression. Taken together, these results suggested that p29 might contribute to the progression of NSCLC by enhancing cell proliferation, implicating that targeting p29 might provide beneficial effects on the clinical therapy of NSCLC., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

High temperature required A2 (HtrA2) is a serine kinase that is released from mitochondria into the cytosol upon apoptotic stimuli, inducing apoptosis in various cancers. Thus, analysis of the expression of HtrA2 in non-small-cell lung cancer (NSCLC) tissues is needed for the understanding of this malignancy. In this study we firstly analyzed the apoptosis effect of HtrA2 in A549 cells by RNA interference and cisplatin with Western blot and flow cytometry. Then HtrA2 expression was evaluated by Western blot and immunohistochemistry in NSCLC tissues. Western blot and flow cytometry analyses indicated that deletion of HtrA2 was negatively correlated with apoptosis-induced protein in A549 cells. HtrA2 was lowly expressed in NSCLC and significantly associated with histological differentiation and clinical stage. Besides, low expression of HtrA2 was a prognostic factor for NSCLC patients' inferior survival. In conclusion, HtrA2 might promote the apoptosis of NSCLC cells, and serve as a target for NSCLC's treatment., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

Transformer 2β (Tra2β), a member of the serine/arginine-rich-like protein family, is an important RNA-binding protein involved in alternative splice. Deregulation of Tra2β has been observed in several cancers. However, the detailed role of Tra2β in non-small cell lung cancer (NSCLC) has not been elucidated. In this study, the contribution of Tra2β to NSCLC development was investigated. On histological level, the expression of Tra2β was determined by Western and immunohistochemistry assays. It demonstrated that Tra2β was expressed higher in NSCLC tumor tissues compared with adjacent non-tumor tissues. In addition to confirm the association of Tra2β expression with histological differentiation and clinical stage (p < 0.05), we also confirmed significant positive correlation between the expression level of Tra2β and that of Ki67 (p < 0.05, r = 0.446) by Spearman rank correlation test. Moreover, high expression of Tra2β predicted poor prognosis by Kaplan-Meier survival analysis. And Tra2β among with other clinicopathologic variables was an independent prognostic indicator for patients' overall survival by multivariate analysis. On cellular level, Tra2β expression was demonstrated to promote proliferation of NSCLC cells through a series of assays, including serum starvation and release assay, Western blot assay and flow cytometry analysis. Moreover, knockdown of Tra2β was confirmed to inhibit proliferation and to induce apoptosis of NSCLC cells through flow cytometry analysis, western analysis, cell counting kit-8 assay and Tunnel assay. Our results indicated that Tra2β was involved in the tumorigenesis of NSCLC and might be a potential therapeutic target of NSCLC.

Nemo-like kinase (NLK), an evolutionarily conserved serine/threonine kinase, is a critical regulator of various cancers. NLK expression was evaluated by Western blot in 8 paired fresh non-small-cell lung cancer (NSCLC) tissues and immunohistochemistry (IHC) on 83 paraffin-embedded slices. NLK was lowly expressed in NSCLC and significantly associated with NSCLC histological differentiation, clinical stage, lymph node status, and Ki-67. Multivariate analysis indicated that low NLK expression was an independent prognostic factor for NSCLC patients' low survival rate. In vitro, after the release of NSCLC cell line A549 from serum starvation, the expression of NLK was downregulated, whereas the cell-cycle-related proteins were upregulated. In addition, we used RNA interference to knock down NLK expression, then observed its effects on NSCLC's growth in vitro. Western blot analyses indicated that deletion of NLK was positively correlated with cell-cycle-related proteins. The present investigation demonstrated that suppression of NLK expression resulted in significant promotion of proliferation in NSCLC cells. And flow cytometry further indicated that loss of NLK promoted cell proliferation by facilitating S-phase and mitotic entry. Besides, the transcription activity of β-catenin/TCF in A549 cells was remarkably enhanced when NLK was knocked down, which suggested that NLK participated in NSCLC cell proliferation via medulating Wnt signaling pathway. Based on these findings, we can provide a potential strategy for NSCLC therapy., (© 2013 Wiley Periodicals, Inc.)

Vacuolar protein sorting 4B (VPS4B), a member of ATPase family proteins, plays a crucial role in lysosome-dependent degradation. Recently, it was found that VPS4B could negatively regulate breast cancer progression through promoting lysosomal-dependent degradation for EGFR. Nevertheless, other studies found that VPS4B was also essential for cell division and mitosis through insuring the maintenance of centrosome and spindle assembly. Thus, the role of VPS4B in cancer biology remains under debate. In this study, we analyzed the clinical significance of VPS4B in NSCLC. The expression of VPS4B was evaluated by Western blot in 8 paired fresh NSCLC tissues and immunohistochemistry on 105 paraffin-embedded slices. VPS4B was highly expressed in NSCLC and significantly associated with NSCLCs tumor size, histological differentiation, clinical stage and Ki-67. Besides, high VPS4B expression was an independent prognostic factor for NSCLC patients' poor survival. To determine whether VPS4B could regulate the proliferation of NSCLC cells, we knocked down the expression of VPS4B and analyzed the proliferation of A549 NSCLC cells using Western blot, CCK8 and flow cytometry assays, which together indicated that loss of VPS4B could inhibit cell cycle progress. These data suggest that VPS4B may promote the progression of NSCLC and be a biotarget for NSCLCs therapy.

Purpose: A small glutamine-rich tetratricopeptide repeat-containing protein alpha (SGTA) is a 35 kDa protein involved in a number of biological processes. However, the role of SGTA in non-small-cell lung cancer (NSCLC) tumorigenesis has never been elucidated. The purpose of this study was to determine whether SGTA could serve as a biomarker for stratification and prediction of prognosis in NSCLC., Methods: Small glutamine-rich tetratricopeptide repeat-containing protein alpha expression was evaluated by Western blot in 8 paired fresh lung cancer tissues and immunohistochemistry on 83 paraffin-embedded sections. The effect of SGTA was assessed by RNA interference in A549 cells. Serum starvation and refeeding, flow cytometry, CCK-8, and tunnel assays were performed., Results: Small glutamine-rich tetratricopeptide repeat-containing protein alpha was highly expressed in NSCLC and significantly correlated with NSCLC histological differentiation, clinical stage, and Ki-67. Multivariate analysis indicated that SGTA was an independent prognostic factor for NSCLC patients' survival. The present investigation demonstrated that suppression of SGTA expression resulted in a significant decline of proliferation in A549 cells. Besides, SGTA could abolish the toxicity of cisplatin in A549 cells., Conclusions: These findings suggested that SGTA might play an important role in promoting the tumorigenesis of NSCLC, and thus be a promising therapeutic target to prevent NSCLC progression.