Derlin-1 is overexpressed in non-small cell lung cancer and promotes cancer cell invasion via EGFR-ERK-mediated up-regulation of MMP-2 and MMP-9.

Previous studies indicated a role of Derlin-1 in human cancers; however, its expression pattern in non-small cell lung cancer (NSCLC) and the molecular mechanism of Derlin-1 on cancer progression have not been characterized. In the present study, Derlin-1 expression was examined in lung cancer cell lines and human tissues. Derlin-1 overexpression correlated with pTNM stage, lymph node metastasis, and poor overall survival. siRNA knockdown of Derlin-1 impaired anchorage-dependent and anchorage-independent cell growth and invasion in A549 and H1299 cell lines, and its overexpression promoted proliferation and invasion in HBE and LTE cell lines. Derlin-1 depletion decreased matrix metalloproteinase (MMP)-2/9 at both protein and mRNA levels, with decreased MAP kinase/extracellular signal-regulated kinase (ERK)/ERK phosphorylation. Derlin-1 overexpression up-regulated MMP-2/9 expression and ERK phosphorylation, which could be reversed by MAP kinase/ERK kinase inhibitor, PD98059. The effect of Derlin-1 on MMP-2/9 up-regulation was abolished in ERK1/2 siRNA-treated cells. Further analysis showed that Derlin-1 overexpression induced EGFR phosphorylation. EGFR inhibitor blocked Derlin-1-mediated up-regulation of EGFR and ERK phosphorylation. MMP-2/9 and p-ERK up-regulation by Derlin-1 was partly blocked in EGFR-depleted cells with siRNA treatment. Immunoprecipitation confirmed the association between Derlin-1 and EGFR. In summary, our results showed that Derlin-1 is overexpressed in NSCLC and promotes invasion by EGFR-ERK-mediated up-regulation of MMP-2 and MMP-9. Derlin-1 may serve as a therapeutic target for NSCLC.

Overexpression of CRKL correlates with poor prognosis and cell proliferation in non-small cell lung cancer.

Crk-Like (CRKL) is an adapter protein that has crucial roles in multiple biological processes, including cell proliferation, adhesion, and migration. Amplification of CRKL gene was found in non-small cell lung cancer (NSCLC). However, the expression pattern of CRKL protein and its clinical significance in human NSCLC have not been well characterized to date. In this study, expression of CRKL was evaluated in 131 NSCLC tissues by immumohistochemistry. CRKL protein was up-regulated in the lung carcinomas compared with adjacent normal lung tissue. Overexpression of CRKL was found in 58 of 131 (44.3%) NSCLC samples and correlated with poor tumor differentiation (P = 0.0042), histological type (adenocarcinoma; P = 0.001), advanced p-TNM stage (P = 0.0004), nodal metastasis (P = 0.0273), high proliferation index (P = 0.0062) and poor overall survival (P = 0.0084). Further univariate and multivariate analysis showed a significant association of CRKL overexpression and worse overall survival in lung cancer patients. In addition, overexpression of CRKL in HBE and H1299 cell lines promoted cell proliferation by facilitating cell cycle progression. Further analysis of cell cycle related molecules showed that CRKL induced cyclin D1, cyclin B1 expression, and increased Rb phosphorylation. In conclusion, this study demonstrated overexpression of CRKL correlated with poor prognosis and lung cancer proliferation by cell cycle regulation.

Ataxia-telangiectasia group D complementing gene (ATDC) upregulates matrix metalloproteinase 9 (MMP-9) to promote lung cancer cell invasion by activating ERK and JNK pathways.

Although the expression pattern and biological functions of ataxia-telangiectasia group D complementing gene (ATDC) had been implicated in several types of cancer, the roles and potential mechanisms of ATDC in lung cancer cell invasion are still ambiguous. In this study, we used gain- and loss-of-function analyses to explore the roles and potential mechanisms of ATDC in lung cancer cell invasion. siRNA knockdown of ATDC impaired cell invasion in A549 and H1299 cell lines, and its overexpression promoted cell invasion in HBE cell line. ATDC may contribute to the invasive ability of lung cancer cells by promoting the expression of invasion-related matrix metalloproteinase 9 (MMP-9). In addition, ATDC increased activating protein 1 (AP-1) reporter luciferase activity and the protein and mRNA levels of c-Jun and c-Fos. We further demonstrated that the roles of ATDC on cell invasion, MMP-9 upregulation, and AP-1 activation were dependent on extracellular signal-regulated protein kinase (ERK) and c-Jun N-terminal kinase (JNK) pathway activation, and ERK inhibitor U0126 or JNK inhibitor SP600125 blocked these effects of ATDC. These results suggested that ATDC upregulates MMP-9 to promote lung cancer cell invasion by activating ERK and JNK pathways.

Abnormal expression of Pygopus 2 correlates with a malignant phenotype in human lung cancer.

BACKGROUND: Pygopus 2 (Pygo2) is a Pygo family member and an important component of the Wnt signaling transcriptional complex. Despite this data, no clinical studies investigating Pygo2 expression in lung cancer have yet been reported. METHODS: In the present study, the expression patterns of Pygo2 were evaluated by immunochemistry in 168 patients with non-small cell lung cancer (NSCLC). We used small interfering RNA (siRNA) to specifically silence Pygo2, and investigated its effect on cell growth by an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry analysis in human lung cancer cell lines. RESULTS: Immunohistochemical analysis showed low expression of Pygo2 in normal lung tissues and increased nuclear expression in lung cancer tissues, either with or without perinuclear expression. Abnormal Pygo2 expression was associated with poor differentiation and a high Tumor (T), Node (N) and Metastases (M) stage in NSCLC patients, and correlated with poor prognosis. Using MTT assay we observed that Pygo2 downregulation inhibited cell proliferation; in addition, flow cytometry analysis showed that Pygo2 knockdown induced apoptosis and increased numbers of G1-phase cells and a reduction in S-phase cells. CONCLUSIONS: We therefore conclude that abnormal Pygo2 protein expression may be a marker for advanced NSCLC. Furthermore, Pygo2 knockdown suppresses cell growth.

CIP2A is overexpressed in non-small cell lung cancer and correlates with poor prognosis.

BACKGROUND: Cancerous inhibitor of protein phosphatase 2A (CIP2A) is an oncoprotein inhibiting proteolytic degradation of c-MYC. In this study, we investigated the clinical relevance of CIP2A in NSCLC. MATERIALS AND METHODS: We analyzed CIP2A mRNA expression in 29 NSCLC tissues using quantitative reverse transcription polymerase chain reaction (RT-QPCR). We also examined the expression of CIP2A protein by immunohistochemistry in 90 lung cancer specimens and correlated its expression with c-MYC expression and clinicopathological parameters. The functional roles of CIP2A in lung cancer cell lines were evaluated by small interfering RNA-mediated depletion of the protein followed by analyses of cell proliferation and invasion. RESULTS: In 29 lung cancer tissues examined, 24 of them (82.7%) exhibited much stronger levels of CIP2A mRNA compared with their corresponding normal tissues. Moreover, CIP2A mRNA expression levels correlated with c-MYC mRNA levels. Furthermore, CIP2A protein was found to be overexpressed in 72.2% of 90 human lung cancer samples and correlated with poor survival (P < 0.05). In addition, the CIP2A status was a significant prognostic factor for NSCLC patients (P = 0.0136). Depleting CIP2A expression inhibited growth and clonogenic potential in lung cancer cell lines. CONCLUSIONS: CIP2A is an oncoprotein overexpressed in NSCLC, and its expression is associated with poor prognosis and malignant cell proliferation.

delta-Catenin promotes malignant phenotype of non-small cell lung cancer by non-competitive binding to E-cadherin with p120ctn in cytoplasm.

As a member of the catenin family, little is known about the clinical significance and possible mechanism of delta-catenin expression in numerous tumours. We examined the expression of delta-catenin by immunohistochemistry in 115 cases of non-small cell lung cancer (NSCLC) (including 65 cases with follow-up records and 50 cases with paired lymph node metastasis lesions). The mRNA and protein expression of delta-catenin was also detected in 30 cases of paired lung cancer tissues and normal lung tissues by RT-PCR and western blotting, respectively. Co-immunoprecipitation was used to examine whether delta-catenin competitively bound to E-cadherin with p120ctn in lung cancer cells or not. The effects of delta-catenin on the activity of small GTPases and the biological behaviour of lung cancer cells were explored by pull-down assay, flow cytometry, MTT, and Matrigel invasive assay. The results showed that the mRNA and protein expression of delta-catenin was increased in lung cancer tissues; the positive expression rate of delta-catenin was significantly increased in adenocarcinoma, stage III-IV, paired lymph node metastasis lesions, and primary tumours with lymph node metastasis (all p < 0.05); and the postoperative survival period of patients with delta-catenin-positive expression was shorter than that of patients with delta-catenin-negative expression (p < 0.05). No competition between delta-catenin and p120ctn for binding to E-cadherin in cytoplasm was found in two lung cancer cell lines. By regulating the activity of small GTPases and changing the cell cycle, delta-catenin could promote the proliferation and invasion of lung cancer cells. We conclude that delta-catenin is an oncoprotein overexpressed in NSCLC and that increased delta-catenin expression is critical for maintenance of the malignant phenotype of lung cancer.

Axin downregulates TCF-4 transcription via beta-catenin, but not p53, and inhibits the proliferation and invasion of lung cancer cells.

BACKGROUND: We previously reported that overexpression of Axin downregulates T cell factor-4 (TCF-4) transcription. However, the mechanism(s) by which Axin downregulates the transcription and expression of TCF-4 is not clear. It has been reported that beta-catenin promotes and p53 inhibits TCF-4 transcription, respectively. The aim of this study was to investigate whether beta-catenin and/or p53 is required for Axin-mediated downregulation of TCF-4. RESULTS: Axin mutants that lack p53/HIPK2 and/or beta-catenin binding domains were expressed in lung cancer cells, BE1 (mutant p53) and A549 (wild type p53). Expression of Axin or AxinDeltap53 downregulates beta-catenin and TCF-4, and knock-down of beta-catenin upregulates TCF-4 in BE1 cells. However, expression of AxinDeltabeta-ca into BE1 cells did not downregulate TCF-4 expression. These results indicate that Axin downregulates TCF-4 transcription via beta-catenin. Although overexpression of wild-type p53 also downregulates TCF-4 in BE1 cells, cotransfection of p53 and AxinDeltabeta-ca did not downregulate TCF-4 further. These results suggest that Axin does not promote p53-mediated downregulation of TCF-4. Axin, AxinDeltap53, and AxinDeltabeta-ca all downregulated beta-catenin and TCF-4 in A549 cells. Knock-down of p53 upregulated beta-catenin and TCF-4, but cotransfection of AxinDeltabeta-ca and p53 siRNA resulted in downregulation of beta-catenin and TCF-4. These results indicate that p53 is not required for Axin-mediated downregulation of TCF-4. Knock-down or inhibition of GSK-3beta prevented Axin-mediated downregulation of TCF-4. Furthermore, expression of Axin and AxinDeltap53, prevented the proliferative and invasive ability of BE1 and A549, expression of AxinDeltabeta-ca could only prevented the proliferative and invasive ability effectively. CONCLUSIONS: Axin downregulates TCF-4 transcription via beta-catenin and independently of p53. Axin may also inhibits the proliferation and invasion of lung cancer cells via beta-catenin and p53.

Overexpression of SCC-S2 correlates with lymph node metastasis and poor prognosis in patients with non-small-cell lung cancer.

The objective of the current study was to investigate the expression pattern and clinicopathological significance of SCC-S2 in patients with non-small-cell lung cancer (NSCLC). The expression profile of SCC-S2 in NSCLC tissues and adjacent noncancerous lung tissues was detected by real-time RT-PCR, western blot analysis, and immunohistochemistry. In 25 lung cancer tissues examined, 18 (72%) of them exhibited stronger levels of SCC-S2 mRNA compared with their corresponding normal tissues. SCC-S2 protein level was up-regulated in cancerous lung tissues compared to adjacent normal tissue. Moreover, the expression level of SCC-S2 in 93 archived NSCLC tissues was measured by immunohistochemical staining. SCC-S2 was found to be overexpressed in 71 of 93 (76.3%) human lung cancer samples and correlated with lymph node metastasis (P = 0.0181), p-TNM stage (P = 0.0042), Ki-67 expression (P = 0.0028), and poor survival (P = 0.012). In addition, depleting SCC-S2 expression by small-interfering RNA inhibited growth and invasion in lung cell lines. These results indicate that SCC-S2 plays an important role in NSCLC and might be a useful therapeutic target of NSCLC.

P120-catenin isoforms 1A and 3A differently affect invasion and proliferation of lung cancer cells.

Different isoforms of p120-catenin (p120ctn), a member of the Armadillo gene family, are variably expressed in different tissues as a result of alternative splicing and the use of multiple translation initiation codons. When expressed in cancer cells, these isoforms may confer different properties with respect to cell adhesion and invasion. We have previously reported that the p120ctn isoforms 1 and 3 were the most highly expressed isoforms in normal lung tissues, and their expression level was reduced in lung tumor cells. To precisely define their biological roles, we transfected p120ctn isoforms 1A and 3A into the lung cancer cell lines A549 and NCI-H460. Enhanced expression of p120ctn isoform 1A not only upregulated E-cadherin and beta-catenin, but also downregulated the Rac1 activity, and as a result, inhibited the ability of cells to invade. In contrast, overexpression of p120ctn isoform 3A led to the inactivation of Cdc42 and the activation of RhoA, and had a smaller influence on invasion. However, we found that isoform 3A had a greater ability than isoform 1A in both inhibiting the cell cycle and reducing tumor cell proliferation. The present study revealed that p120ctn isoforms 1A and 3A differently regulated the adhesive, proliferative, and invasive properties of lung cancer cells through distinct mechanisms.

Epidermal Growth Factor Receptor Gene Mutation Status in Primary Lung Adenocarcinoma and Corresponding Bone Metastases.

BACKGROUND: The aim of this study was to compare epidermal growth factor receptor (EGFR) mutations between primary tumors and corresponding bone metastases (BMs) in lung adenocarcinoma. MATERIALS AND METHODS: In total, 115 paired primary lung adenocarcinoma and corresponding BM tumors were analyzed for EGFR mutations by Amplification Refractory Mutation System. RESULTS: EGFR mutations were detected in 61 primary lung adenocarcinomas (53.04%) and in 67 corresponding metastases (58.26%), respectively. The EGFR mutation rate was significantly higher in female and in never-smoker patients. The consistency of EGFR mutations between the 115 matched BMs and primary tumor tissue samples reached to 80.87%, and the disparity was 19.13%. Mutations in exons 19 (19-del) and 21 (point mutation L858R) were the predominant mutation type. CONCLUSIONS: The concordance rate demonstrated the feasibility of EGFR mutations in corresponding metastases using Amplification Refractory Mutation System when the primary tumor tissue is unavailable in the lung adenocarcinoma patients, and the inconsistency indicates that corresponding metastasis being screened simultaneously with the primary tumor samples may present some supplementary information for the patients.

Ablation of p120-catenin enhances invasion and metastasis of human lung cancer cells.

p120-catenin, a member of the Armadillo gene family, has emerged as both a master regulator of cadherin stability and an important modulator of small GTPase activities. Therefore, it plays novel roles in tumor malignant phenotype, such as invasion and metastasis. We have reported previously that abnormal expression of p120-catenin is associated with lymph node metastasis in lung squamous cell carcinomas (SCC) and adenocarcinomas. To investigate the role and possible mechanism of p120-catenin in lung cancer, we knocked down p120-catenin using small interfering RNA (siRNA). We found that ablation of p120-catenin reduced the levels of E-cadherin and beta-catenin proteins, as well as the mRNA of beta-catenin. Furthermore, p120-catenin depletion inactivated RhoA, but increased the activity of Cdc42 and Rac1, and promoted proliferation and the invasive ability of lung cancer cells both in vitro and in vivo. Our data reveal that p120-catenin gene knockdown enhances the metastasis of lung cancer cells, probably by either depressing cell-cell adhesion due to lower levels of E-cadherin and beta-catenin, or altering the activity of small GTPase, such as inactivation of RhoA and activation of Cdc42/Rac1.

Dishevelled family proteins are expressed in non-small cell lung cancer and function differentially on tumor progression.

BACKGROUND: Dishevelled (Dvl) family proteins are cytoplasmic mediators of the Wnt/beta-catenin signaling pathway and have recently been linked to cancers. However, the roles of individual Dvls and their expression in human cancers are poorly defined. This work aimed to characterize the expression of Dvls and their correlation to clinicopathological factors and beta-catenin expression in non-small cell lung cancer (NSCLC). METHODS: We used immunohistochemistry to assess the presence of the three Dvl family proteins in 113 individual NSCLC specimens. Thirty-nine of the 113 cases were examined further for Dvl and beta-catenin protein expression in matched primary growths and autologous nodal metastases. We also examined the effect of Dvl-1 and Dvl-3 overexpression on beta-catenin expression and the invasive ability of A549 and QG56 lung cancer cells. RESULTS: The positive expression rate in primary tumors was 53.1% (60/113) for total Dvl, 36.3% (41/113) for Dvl-1, 36.3% (41/113) for Dvl-2 and 41.6% (47/113) for Dvl-3, while normal adult bronchial and alveolar epithelia showed negative expression of all these proteins. The expression levels of all three Dvl proteins were significantly higher in adenocarcinomas than in squamous carcinomas, and were associated with poor tumor differentiation. The positive expression of Dvl-1 and Dvl-2 proteins was correlated to advanced pTNM stages (III-IV vs. I-II). In addition, the expression levels of Dvl-1 and Dvl-3 were significantly higher in nodal metastases than in primary growths, with the Dvl-1 expression correlating to beta-catenin expression in the metastases. Exogenous expression of Dvl-1 and Dvl-3 both enhanced the invasive ability of A549 and QG56 cells, but had differential effects on beta-catenin protein expression in either cell line, without influencing beta-catenin mRNA levels. CONCLUSIONS: Expression of Dvl family proteins, Dvl-1, Dvl-2 and Dvl-3, is common in NSCLCs. They may contribute to the progression of NSCLCs, but Dvl-1 and Dvl-3 may function on this process through different signaling pathways.

The Expression Pattern of p120-Catenin is Associated With Acquired Resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Non-Small Cell Lung Cancer.

BACKGROUND: Previous research connects p120-catenin (p120ctn) with epidermal growth factor receptor (EGFR) signaling pathways, which presents a potential role for p120ctn in EGFR tyrosine kinase inhibitor (EGFR-TKIs) resistance. However, a direct correlation between the expression pattern of p120ctn in solid tumors and the therapeutic effect of EGFR-TKIs has not yet been demonstrated. METHODS AND RESULTS: In this study, the expression pattern of p120ctn was examined in patients with the EGFR gene mutation in lung adenocarcinoma, and p120ctn was found to have different patterns of expression even in the same mutation type. The therapeutic effect of EGFR-TKIs was investigated in these patients, and patients with an abnormal expression of p120ctn were found to be more likely to have drug resistance. A gefitinib-resistant lung cancer cell line was established and alterations in the p120ctn expression pattern were also observed in vitro. CONCLUSIONS: Therefore, this study demonstrates that the expression pattern of p120ctn is associated with acquired resistance to EGFR-TKIs in lung cancer, providing information toward addressing the problem of drug resistance in patients with non-small cell lung cancer.

Comparison of Epidermal Growth Factor Receptor Gene Mutations Identified Using Pleural Effusion and Primary Tumor Tissue Samples in Non-Small Cell Lung Cancer.

BACKGROUND: Although the use of pleural effusion samples for epidermal growth factor receptor (EGFR) testing in lung cancer is increasing, the accuracy rate and effectiveness of identifying EGFR mutations using these samples, rather than primary tumor tissue samples, is not established. MATERIALS AND METHODS: One hundred ninety-two advanced, non-small cell lung cancer patients were enrolled into this study. All patients had primary tumor tissue and corresponding pleural effusion samples, and we employed the Amplification Refractory Mutation System to detect EGFR gene mutations in these samples. RESULT: The number of EGFR mutations detected in primary tumor tissue and pleural effusion samples was 119 (61.98%) and 113 (58.85%), respectively. The EGFR-mutation rate was significantly higher in female than in male patients, and in adenocarcinoma than in nonadenocarcinoma patients (P=0.000). Single mutations in exons 19 and 21 were the predominant observed mutation type, and the overall concordance rate of EGFR-mutation status between the 192 matched pleural effusion and primary tumor tissue samples was 86.98%. CONCLUSIONS: We observed a high concordance rate between EGFR mutations identified using primary tumor tissue and corresponding pleural effusion samples by Amplification Refractory Mutation System. Thus, it is likely that pleural effusion sampling from advanced non-small cell lung cancer patients, especially those with adenocarcinoma, may be effective in EGFR-mutation screening.

The P21-activated kinase expression pattern is different in non-small cell lung cancer and affects lung cancer cell sensitivity to epidermal growth factor receptor tyrosine kinase inhibitors.

Exploring methods for increasing epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) sensitivity has become a major focus in non-small cell lung cancer (NSCLC). Major downstream effectors of the Rho family small guanosine triphosphatases, P21-activated kinases (PAKs) activate the main signaling pathways downstream of EGFR and thus promote tumor cell proliferation. In this study, we explored the expression pattern of phosphorylated PAKs in NSCLC and their potential value as drug targets for treating cancer. The expression and prognostic significance of phosphorylated group I and II PAKs were evaluated in 182 patients with NSCLC. Immunohistochemical analysis revealed low group I PAK expression in normal lung tissues and increased expressed in the cytoplasm, particularly in lung squamous cell carcinoma. Abnormal group I PAK expression was associated with lymph node metastases and high tumor-node-metastases (TNM) stage in NSCLC patients and correlated with poor prognosis. We used group I PAK inhibitor (IPA3) to specifically decrease group I PAK activity in human lung cancer cell lines. Decreased group I PAK activity inhibited cell proliferation and combined IPA3 and EGFR-TKI (gefitinib) treatment inhibited cell proliferation in an obvious manner. Together, our results revealed the PAK expression pattern in NSCLC, and a role for group I PAK in cell proliferation, which provides evidence that decreased PAK activity may have a potential application as a molecular targeted therapy in advanced NSCLC.

Kaiso interacts with p120-catenin to regulate ß-catenin expression at the transcriptional level.

BACKGROUND: We have reported that p120-catenin could regulate ß-catenin transcription in lung cancer cells, but the specific mechanism is unclear. METHODS AND RESULTS: In this study, bisulfite sequencing PCR showed that the ß-catenin promoter region in SPC-A-1 and LTEP-a-2 lung cancer cell lines has Kaiso binding sites sequences and CpG islands which may combine with Kaiso. The demethylating reagent 5-Aza-2'-deoxycytidine significantly upregulated ß-catenin mRNA expression in lung cancer cell lines, whereas expression was significantly reduced following transfection with Kaiso. However, the upregulation of ß-catenin mRNA expression after treatment with 5-Aza-2'-deoxycytidine was not reduced by subsequent transfection with Kaiso cDNA. Chromatin immunoprecipitation showed that, in lung cancer cell lines, methylated CpG-dinucleotides sequences combined with Kaiso and the Kaiso binding sites sequence did not. The capacity of Kaiso to combine with p120-catenin isoforms was confirmed by immunoprecipitation. CONCLUSIONS: Based on these results, we concluded that Kaiso participates in the regulation by p120ctn of ß-catenin mRNA expression in the lung cancer cell lines.

Leucine zipper tumor suppressor 2 inhibits cell proliferation and regulates Lef/Tcf-dependent transcription through Akt/GSK3ß signaling pathway in lung cancer.

Leucine zipper tumor suppressor 2 (LZTS2) is implicated in several cancers; however, its biological mechanisms in non-small cell lung cancer (NSCLC) are not yet understood. We found that low levels of LZTS2 in NSCLC were correlated with tumor and nodal status. LZTS2 could inhibit cell proliferation and cell cycle transition at the G1/S phase and was implicated in the regulation of proteins associated with the canonical Wnt pathway, including GSK3ß and ß-catenin through inactivating the Akt pathway. These results provide novel mechanistic insight into the biological roles of LZTS2 in lung cancer cells.

Ataxia-telangiectasia group D complementing gene (ATDC) promotes lung cancer cell proliferation by activating NF-κB pathway.

Previous studies suggested Ataxia-telangiectasia group D complementing gene (ATDC) as an oncogene in many types of cancer. However, its expression and biological functions in non-small cell lung cancer (NSCLC) remain unclear. Herein, we investigated its expression pattern in 109 cases of human NSCLC samples by immunohistochemistry and found that ATDC was overexpressed in 62 of 109 NSCLC samples (56.88%). ATDC overexpression correlated with histological type (p<0.0001), tumor status (p = 0.0227) and histological differentiation (p = 0.0002). Next, we overexpressed ATDC in normal human bronchial epithelial cell line HBE and depleted its expression in NSCLC cell lines A549 and H1299. MTT and colony formation assay showed that ATDC overexpression promoted cell proliferation while its depletion inhibited cell growth. Furthermore, cell cycle analysis showed that ATDC overexpression decreased the percentage of cells in G1 phase and increased the percentage of cells in S phase, while ATDC siRNA treatment increased the G1 phase percentage and decreased the S phase percentage. Further study revealed that ATDC overexpression could up-regulate cyclin D1 and c-Myc expression in HBE cells while its depletion down-regulated cyclin D1 and c-Myc expression in A549 and H1299 cells. In addition, ATDC overexpression was also associated with an increased proliferation index, cyclin D1 and c-Myc expression in human NSCLC samples. Further experiments demonstrated that ATDC up-regulated cyclin D1 and c-Myc expression independent of wnt/ß-catenin or p53 signaling pathway. Interestingly, ATDC overexpression increased NF-κB reporter luciferase activity and p-IκB protein level. Correspondingly, NF-κB inhibitor blocked the effect of ATDC on up-regulation of cyclin D1 and c-Myc. In conclusion, we demonstrated that ATDC could promote lung cancer proliferation through NF-κB induced up-regulation of cyclin D1 and c-Myc.