Search

Our previous big data analyses showed a high level of association between chitinase 3 like1 (CHI3L1) expression and lung tumor development. In the present study, we investigated whether a CHI3L1-inhibiting chemical, 2-({3-[2-(1-cyclohexen-1-yl)ethyl]-6,7-dimethoxy-4-oxo-3,4-dihydro-2-quinazolinyl}sulfanyl)-N-(4-ethylphenyl)butanamide (K284), could inhibit lung metastasis and studied its mechanism of action. We investigated the antitumor effect of K284 both in vitro and in vivo. K284 (0.5 mg·kg -1 body weight) significantly inhibited lung metastasis in in vivo models after injection of murine melanoma cells (B16F10) or adenocarcinomic human alveolar basal epithelial cells (A549). K284 significantly and concentration-dependently also inhibited cancer cell proliferation and migration in the A549 and H460 lung cancer cell lines. We found that the binding of K284 to the chitin-binding domain (CBD) of CHI3L1 prevented the binding of CHI3L1 to its receptor, interleukin-13 receptor subunit alpha-2 (IL-13Rα2), thereby suppressing the CHI3L1 signal. This blocking of the CHI3L1-IL-13Rα2 signal caused the inhibition of c-Jun N-terminal kinase (JNK)-activator protein 1 (AP-1) signals, resulting in the prevention of lung metastasis and cancer cell growth. Our data demonstrate that K284 may serve as a potential candidate anticancer compound targeting CHI3L1., (© 2021 The Authors. Molecular Oncology published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Background: Chitinase 3 like 1 protein (Chi3L1) is expressed in several cancers, and a few evidences suggest that the secreted Chi3L1 contributes to tumor development. However, the molecular mechanisms of intracellular Chi3L1 are unknown in the lung tumor development., Methods: In the present study, we generated Chi3L1 knockout mice (Chi3L1 KO(-/-) ) using CRISPR/Cas9 system to investigate the role of Chi3L1 on lung tumorigenesis., Results: We established lung metastasis induced by i.v. injections of B16F10 in Chi3L1 KO(-/-) . The lung tumor nodules were significantly reduced in Chi3L1 KO(-/-) and protein levels of p53, p21, BAX, and cleaved-caspase 3 were significantly increased in Chi3L1 KO(-/-) , while protein levels of cyclin E1, CDK2, and phsphorylation of STAT3 were decreased in Chi3L1 KO(-/-) . Allograft mice inoculated with B16F10 also suppressed tumor growth and increased p53 and its target proteins including p21 and BAX. In addition, knockdown of Chi3L1 in lung cancer cells inhibited lung cancer cell growth and upregulated p53 expression with p21 and BAX, and a decrease in phosphorylation of STAT3. Furthermore, we found that intracellular Chi3L1 physically interacted and colocalized with p53 to inhibit its protein stability and transcriptional activity for target genes related with cell cycle arrest and apoptosis. In lung tumor patient, we clinically found that Chi3L1 expression was upregulated with a decrease in p53 expression, as well as we validated that intracellular Chi3L1 was colocalized, reversely expressed, and physically interacted with p53, which results in suppression of the expression and function of p53 in lung tumor patient., Conclusions: Our studies suggest that intracellular Chi3L1 plays a critical role in the lung tumorigenesis by regulating its novel target protein, p53 in both an in vitro and in vivo system.

Rationale: Signal transducer and activator of transcription-3 (STAT3) plays a pivotal role in cancer biology. Many small-molecule inhibitors that target STAT3 have been developed as potential anticancer drugs. While designing small-molecule inhibitors that target the SH2 domain of STAT3 remains the leading focus for drug discovery, there has been a growing interest in targeting the DNA-binding domain (DBD) of the protein. Methods: We demonstrated the potential antitumor activity of a novel, small-molecule (E)-2-methoxy-4-(3-(4-methoxyphenyl)prop-1-en-1-yl)phenol (MMPP) that directly binds to the DBD of STAT3, in patient-derived non-small cell lung cancer (NSCLC) xenograft model as well as in NCI-H460 cell xenograft model in nude mice. Results: MMPP effectively inhibited the phosphorylation of STAT3 and its DNA binding activity in vitro and in vivo . It induced G1-phase cell cycle arrest and apoptosis through the regulation of cell cycle- and apoptosis-regulating genes by directly binding to the hydroxyl residue of threonine 456 in the DBD of STAT3. Furthermore, MMPP showed a similar or better antitumor activity than that of docetaxel or cisplatin. Conclusion: MMPP is suggested to be a potential candidate for further development as an anticancer drug that targets the DBD of STAT3., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

Piperlongumine has anti-cancer activity in numerous cancer cell lines via various signaling pathways. But there has been no study regarding the mechanisms of PL on the lung cancer yet. Thus, we evaluated the anti-cancer effects and possible mechanisms of PL on non-small cell lung cancer (NSCLC) cells in vivo and in vitro. Our findings showed that PL induced apoptotic cell death and suppressed the DNA binding activity of NF-κB in a concentration dependent manner (0-15 μM) in NSCLC cells. Docking model and pull down assay showed that PL directly binds to the DNA binding site of nuclear factor-κB (NF-κB) p50 subunit, and surface plasmon resonance (SPR) analysis showed that PL binds to p50 concentration-dependently. Moreover, co-treatment of PL with NF-κB inhibitor phenylarsine oxide (0.1 μM) or p50 siRNA (100 nM) augmented PL-induced inhibitory effect on cell growth and activation of Fas and DR4. Notably, co-treatment of PL with p50 mutant plasmid (C62S) partially abolished PL-induced cell growth inhibition and decreased the enhanced expression of Fas and DR4. In xenograft mice model, PL (2.5-5 mg/kg) suppressed tumor growth of NSCLC dose-dependently. Therefore, these results indicated that PL could inhibit lung cancer cell growth via inhibition of NF-κB signaling pathway in vitro and in vivo.

Snake venom toxin (SVT) from Vipera lebetina turanica contains a mixture of different enzymes and proteins. Peroxiredoxin 6 (PRDX6) is known to be a stimulator of lung cancer cell growth. PRDX6 is a member of peroxidases, and has calcium-independent phospholipase A2 (iPLA2) activities. PRDX6 has an AP-1 binding site in its promoter region of the gene. Since AP-1 is implicated in tumor growth and PRDX6 expression, in the present study, we investigated whether SVT inhibits PRDX6, thereby preventing human lung cancer cell growth (A549 and NCI-H460) through inactivation of AP-1. A docking model study and pull down assay showed that SVT completely fits on the basic leucine zipper (bZIP) region of c-Fos of AP-1. SVT (0-10 μg/ml) inhibited lung cancer cell growth in a concentration dependent manner through induction of apoptotic cell death accompanied by induction of cleaved caspase-3, -8, -9, Bax, p21 and p53, but decreased cIAP and Bcl2 expression via inactivation of AP-1. In an xenograft in vivo model, SVT (0.5 mg/kg and 1 mg/kg) also inhibited tumor growth accompanied with the reduction of PRDX6 expression, but increased expression of proapoptotic proteins. These data indicate that SVT inhibits tumor growth via inhibition of PRDX6 activity through interaction with its transcription factor AP-1.

Activation of nuclear factor kappa-B (NF-κB) is implicated in drug resistant of lung cancer cells. Our previous data showed that thiacremonone inhibited activation of NF-κB. In the present study, we investigated whether thiacremonone enhanced susceptibility of lung cancer cells to a common anti-cancer drug paclitaxel by further inhibition of NF-κB. Thus, we used the threefold lower doses of IC50 values (50 μg/ml thiacremonone and 2.5 nM paclitaxel). We found that combination treatment with thiacremonone and paclitaxel was more susceptible (combination index; 0.40 in NCI-H460 cells and 0.46 in A549 cells) in cell growth inhibition of two types of lung cancer cell lines compared to a single agent treatment. Consistent with the combination effect on cancer cell growth inhibition, the combination treatment further induced apoptotic cell death and arrested the cancer cells in G2/M phase accompanied with a much lower expression of cdc2 and cyclin B1, and inhibited colony formation. Much more inactivation of NF-κB and greater expression of NF-κB target apoptosis regulated genes such as caspase-8 and PARPs were found by the combination treatment. Molecular model and pull down assay as well as MALDI-TOF analysis demonstrated that thiacremonone directly binds to p50. These data indicated that thiacremonone leads to increased apoptotic cell death in lung cancer cell lines through greater inhibition of NF-κB by the combination treatment with paclitaxel.

Ginsenoside Rg3 (Rg3), a pharmacologically active compound from red ginseng, has been reported to induce cell death in various cancer cell lines, although the specific mechanisms have not been well established. In the present study, Rg3 treatment to A549 human lung adenocarcinoma led to cell death via not only apoptotic pathways but also the downregulation of epidermal growth factor receptor (EGFR). We used cross-linker and cell enzyme-linked immunosorbent assays to show that Rg3 inhibited EGFR dimerization by EGF stimulation and caused EGFR internalization from the cell membrane. Among several important phosphorylation sites in cytoplasmic EGFR, Rg3 increased the phosphorylation of tyrosine 1045 (pY1045) and serine 1046/1047 (pS1046/1047) for EGFR degradation and coincidently, attenuated pY1173 and pY1068 for mitogen-activated protein kinase activity. These effects were amplified under EGF-pretreated Rg3 stimulation. In vivo experiments showed that the average volume of the tumors treated with 30 mg/kg of Rg3 was significantly decreased by 40% compared with the control. Through immunohistochemistry, we detected the fragmentation of DNA, the accumulation of Rg3, and the reduction of EGFR expression in the Rg3-treated groups. Here, we provide the first description of the roles of Rg3 in the reduction of cell surface EGFR, the attenuation of EGFR signal transduction, and the eventual activation of apoptosis in A549 human lung adenocarcinoma., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Phenolic compounds (flavonoids and phenolic acid derivatives) are the most important pharmacologically active ingredients, and these compounds could inhibit proliferation of human cancer cells by inducing of apoptotic cell death. Here we focused on the anticancer effects of tectochrysin on human non-small-cell lung cancer (NSCLC) cells and its mechanism of action. We analysed the activity of tectochrysin on NSCLC cells (A549 and NCI-H460) by use of Western blot analysis for major apoptotic proteins and death receptor expression. We also used EMSA for effects on STAT3 DNA binding activity. Tectochrysin (0-80 μM) suppressed the growth of A549 and NCI-H460 lung cancer cells by inducing of apoptotic cell death in a concentration dependent manner. Expression of DR3 and Fas as well as DR downstream pro-apoptotic proteins including cleaved caspase-3, cleaved caspase-8, cleaved caspase-9 and Bax were concomitantly increased, but the expression of anti-apoptotic proteins; Bcl-2 was decreased in both cancer cells. In addition, tectochrysin treatment also inhibited phosphorylation of STAT3 in A549 and NCI-H460 cells. However, deletion of DR3 and Fas by small interfering RNA significantly reversed tectochrysin-induced cell growth inhibitory effect as well as down regulation of STAT3 in A549 and NCI-H460 lung cancer cells. Pull down assay and docking model showed interaction of tectochrysin with STAT3. We propose that tectochrysin leads to apoptotic cell death in NSCLC cells through activation of DR3 and Fas expression via inhibition of STAT3 phosphorylation., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Lung cancer remains the leading cause of cancer-related mortality for both men and women. Tumor recurrence and metastasis is the major cause of lung cancer treatment failure and death. The microRNA‑200 (miR-200) family is a powerful regulator of the epithelial-mesenchymal transition (EMT) process, which is essential in tumor metastasis. Nevertheless, miR-200 family target genes that promote metastasis in non-small cell lung cancer (NSCLC) remain largely unknown. Here, we sought to investigate whether the microRNA-200 family regulates our previously identified NSCLC prognostic marker genes associated with metastasis, as potential molecular targets. Novel miRNA targets were predicted using bioinformatics tools based on correlation analyses of miRNA and mRNA expression in 57 squamous cell lung cancer tumor samples. The predicted target genes were validated with quantitative RT-PCR assays and western blot analysis following re-expression of miR-200a, -200b and -200c in the metastatic NSCLC H1299 cell line. The results show that restoring miR-200a or miR-200c in H1299 cells induces downregulation of DLC1, ATRX and HFE. Reinforced miR-200b expression results in downregulation of DLC1, HNRNPA3 and HFE. Additionally, miR-200 family downregulates HNRNPR3, HFE and ATRX in BEAS-2B immortalized lung epithelial cells in quantitative RT-PCR and western blot assays. The miR-200 family and these potential targets are functionally involved in canonical pathways of immune response, molecular mechanisms of cancer, metastasis signaling, cell-cell communication, proliferation and DNA repair in Ingenuity pathway analysis (IPA). These results indicate that re-expression of miR-200 downregulates our previously identified NSCLC prognostic biomarkers in metastatic NSCLC cells. These results provide new insights into miR-200 regulation in lung cancer metastasis and consequent clinical outcome, and may provide a potential basis for innovative therapeutic approaches for the treatment of this deadly disease.

Smoking is responsible for 90% of lung cancer cases. There is currently no clinically available gene test for early detection of lung cancer in smokers, or an effective patient selection strategy for adjuvant chemotherapy in lung cancer treatment. In this study, concurrent coexpression with multiple signaling pathways was modeled among a set of genes associated with smoking and lung cancer survival. This approach identified and validated a 7-gene signature for lung cancer diagnosis and prognosis in smokers using patient transcriptional profiles (n=847). The smoking-associated gene coexpression networks in lung adenocarcinoma tumors (n=442) were highly significant in terms of biological relevance (network precision = 0.91, FDR<0.01) when evaluated with numerous databases containing multi-level molecular associations. The gene coexpression network in smoking lung adenocarcinoma patients was confirmed in qRT-PCR assays of the identified biomarkers and involved signaling pathway genes in human lung adenocarcinoma cells (H23) treated with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Furthermore, the western blotting results of p53, phospho‑p53, Rb and EGFR in NNK-treated H23 and transformed normal human lung epithelial cells (BEAS-2B) support their functional involvement in smoking-induced lung cancer carcinogenesis and progression.

Objective: Smoking is a prominent risk factor for lung cancer. However, it is not an established prognostic factor for lung cancer in clinics. To date, no gene test is available for diagnostic screening of lung cancer risk or prognostication of clinical outcome in smokers. This study sought to identify a smoking associated gene signature in order to provide a more precise diagnosis and prognosis of lung cancer in smokers., Methods and Materials: An implication network based methodology was used to identify biomarkers by modeling crosstalk with major lung cancer signaling pathways. Specifically, the methodology contains the following steps: (1) identifying genes significantly associated with lung cancer survival; (2) selecting candidate genes which are differentially expressed in smokers versus non-smokers from the survival genes identified in Step 1; (3) from these candidate genes, constructing gene coexpression networks based on prediction logic for the smoker group and the non-smoker group, respectively; (4) identifying smoking-mediated differential components, i.e., the unique gene coexpression patterns specific to each group; and (5) from the differential components, identifying genes directly co-expressed with major lung cancer signaling hallmarks., Results: A smoking-associated 6-gene signature was identified for prognosis of lung cancer from a training cohort (n=256). The 6-gene signature could separate lung cancer patients into two risk groups with distinct post-operative survival (log-rank P<0.04, Kaplan-Meier analyses) in three independent cohorts (n=427). The expression-defined prognostic prediction is strongly related to smoking association and smoking cessation (P<0.02; Pearson's Chi-squared tests). The 6-gene signature is an accurate prognostic factor (hazard ratio=1.89, 95% CI: [1.04, 3.43]) compared to common clinical covariates in multivariate Cox analysis. The 6-gene signature also provides an accurate diagnosis of lung cancer with an overall accuracy of 73% in a cohort of smokers (n=164). The coexpression patterns derived from the implication networks were validated with interactions reported in the literature retrieved with STRING8, Ingenuity Pathway Analysis, and Pathway Studio., Conclusions: The pathway-based approach identified a smoking-associated 6-gene signature that predicts lung cancer risk and survival. This gene signature has potential clinical implications in the diagnosis and prognosis of lung cancer in smokers., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Tumor recurrence is the major cause of death in lung cancer treatment. To date, there is no clinically applied gene expression-based model to predict the risk for tumor recurrence in non-small cell lung cancer (NSCLC). We sought to embed crosstalk with major signaling pathways into biomarker identification. Three approaches were used to identify prognostic gene signatures from 442 lung adenocarcinoma samples. Candidate genes co-expressed with 6 or 7 major NSCLC signaling hallmarks were identified from genome-wide coexpression networks specifically associated with different prognostic groups. From these candidate genes, the first approach selected genes significantly associated with disease-specific survival using univariate Cox model. The second approach used random forests to refine the gene signatures; and the third approach used Relief algorithm to form the final gene sets. A total of 21 gene signatures were identified using these three approaches. These gene signatures generated significant prognostic stratifications (log-rank P<0.05 in Kaplan-Meier analyses; hazard ratio >1, P<0.05) in all tumors, stage I only, and in stage I patients not receiving chemotherapy in all training and test sets. In multivariate analyses with age, gender, race, smoking history, cancer stage, and tumor differentiation, a 10-gene signature had a hazard ratio of 3.23 (95% CI: [1.48, 7.06]), which was a more significant prognostic factor than other clinical factors, except cancer stage (III vs. I; with no significant difference). All identified 21 gene signatures outperformed other lung cancer signatures evaluated in the Director's Challenge Study. This study is an important step toward personalized prognosis of tumor recurrence and patient selection for adjuvant chemotherapy, with significant impact on down-stream clinical applications., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Concerns over the potential for multiwalled carbon nanotubes (MWCNT) to induce lung carcinogenesis have emerged. This study sought to (1) identify gene expression signatures in the mouse lungs following pharyngeal aspiration of well-dispersed MWCNT and (2) determine if these genes were associated with human lung cancer risk and progression. Genome-wide mRNA expression profiles were analyzed in mouse lungs (n = 160) exposed to 0, 10, 20, 40, or 80 μg of MWCNT by pharyngeal aspiration at 1, 7, 28, and 56 d postexposure. By using pairwise statistical analysis of microarray (SAM) and linear modeling, 24 genes were selected, which have significant changes in at least two time points, have a more than 1.5-fold change at all doses, and are significant in the linear model for the dose or the interaction of time and dose. Additionally, a 38-gene set was identified as related to cancer from 330 genes differentially expressed at d 56 postexposure in functional pathway analysis. Using the expression profiles of the cancer-related gene set in 8 mice at d 56 postexposure to 10 μg of MWCNT, a nearest centroid classification accurately predicts human lung cancer survival with a significant hazard ratio in training set (n = 256) and test set (n = 186). Furthermore, both gene signatures were associated with human lung cancer risk (n = 164) with significant odds ratios. These results may lead to development of a surveillance approach for early detection of lung cancer and prognosis associated with MWCNT in the workplace.

Situs inversus totalis (SIT) is not itself a premalignant condition, however, rare synchronous or metachronous multiple primary malignancies have been reported. Herein we present a case of synchronous transverse and sigmoid colon cancers and a case of metachronous rectosigmoid colon and gastric cancers in patients with SIT.A 66-year-old male with SIT was referred for a two-month history of hematochezia. Synchronous colonic tumors were found on the proximal transverse and sigmoid colon. The patient underwent open total colectomy and was discharged without incident. A 71-year-old female with rectosigmoid colon cancer and SIT underwent laparoscopy-assisted low anterior resection. Fourteen months after the surgery, the patient developed a single hepatic metastasis and underwent hepatic segmentectomy (S6). Forty-six months after laparoscopy-assisted low anterior resection, the patient developed metachronous early gastric cancer on the antrum and underwent radical subtotal gastrectomy with gastroduodenostomy. The patient is doing well without recurrence for 28 months.

This study presents a novel network methodology to identify prognostic gene signatures. Implication networks based on prediction logic are used to construct genome-wide coexpression networks for different disease states. From the differential components associated with specific disease states, candidate genes that are co-expressed with major disease signal hallmarks are selected. From these candidate genes, top genes that are the most predictive of clinical outcome are identified using univariate Cox model and Relief algorithm. Using this approach, a 13-gene lung cancer prognosis signature was identified, which generated significant prognostic stratifications (log-rank P < 0.05) in Director's Challenge Study (n = 442).

Background and Aims: Genomic instability, as reflected in specific chromosomal aneuploidies and variation in the nuclear DNA content, is a defining feature of human carcinomas. It is solidly established that the degree of genomic instability influences clinical outcome. We have recently identified a 12-gene expression signature that discerned genomically stable from unstable breast carcinomas. This gene expression signature was also useful to predict, with high accuracy, the clinical course in independent multiple published breast cancer cohorts. From a biological point of view, this result confirmed the central role of genomic instability for a tumor's ability to adapt to external challenges and selective pressure, and hence for continued survival fitness. This prompted us to investigate whether this genomic instability signature could also predict clinical outcome in other cancer types of epithelial origin, including colorectal tumors, non-small cell lung carcinomas, and ovarian cancer., Results: The results show that the gene expression signature that defines genomic instability and poor outcome in breast cancer contributes significantly more accurate (p<0.05 compared with random prediction) prognostic information in multiple cancer types independent of established clinical parameters. The 12-gene genomic instability signature stratified patients into high- and low-risk groups with distinct postoperative survival in three non-small cell lung cancer cohorts (n=637) in Kaplan-Meier analyses (log-rank p<0.05). It predicted recurrence in colon cancer patients (n=92) with an overall accuracy greater than 69% (p=0.04) in cross-cohort validation. It quantified relapse-free survival in ovarian cancer (n=124; log-rank p<0.05). Functional pathway analysis revealed interactions between the 12 signature genes and well-known cancer hallmarks., Conclusion: The degree of genomic instability has diagnostic and prognostic implications. It is tempting to speculate that pursuing genomic instability therapeutically could provide entry points for a target that is unique to cancer cells.

Background: Lung cancer remains the leading cause of cancer-related deaths worldwide. The recurrence rate ranges from 35-50% among early stage non-small cell lung cancer patients. To date, there is no fully-validated and clinically applied prognostic gene signature for personalized treatment., Methodology/principal Findings: From genome-wide mRNA expression profiles generated on 256 lung adenocarcinoma patients, a 12-gene signature was identified using combinatorial gene selection methods, and a risk score algorithm was developed with Naïve Bayes. The 12-gene model generates significant patient stratification in the training cohort HLM & UM (n = 256; log-rank P = 6.96e-7) and two independent validation sets, MSK (n = 104; log-rank P = 9.88e-4) and DFCI (n = 82; log-rank P = 2.57e-4), using Kaplan-Meier analyses. This gene signature also stratifies stage I and IB lung adenocarcinoma patients into two distinct survival groups (log-rank P<0.04). The 12-gene risk score is more significant (hazard ratio = 4.19, 95% CI: [2.08, 8.46]) than other commonly used clinical factors except tumor stage (III vs. I) in multivariate Cox analyses. The 12-gene model is more accurate than previously published lung cancer gene signatures on the same datasets. Furthermore, this signature accurately predicts chemoresistance/chemosensitivity to Cisplatin, Carboplatin, Paclitaxel, Etoposide, Erlotinib, and Gefitinib in NCI-60 cancer cell lines (P<0.017). The identified 12 genes exhibit curated interactions with major lung cancer signaling hallmarks in functional pathway analysis. The expression patterns of the signature genes have been confirmed in RT-PCR analyses of independent tumor samples., Conclusions/significance: The results demonstrate the clinical utility of the identified gene signature in prognostic categorization. With this 12-gene risk score algorithm, early stage patients at high risk for tumor recurrence could be identified for adjuvant chemotherapy; whereas stage I and II patients at low risk could be spared the toxic side effects of chemotherapeutic drugs.

The FOXO family of transcription factors elicits cell cycle arrest, apoptosis, and resistance to various physiologic and pathologic stresses relevant to sporadic cancer, such as DNA damage and oxidative stress. Although implicated as tumor suppressors, FOXO genetic inactivation has not been observed in human cancer. In an investigation of the two major types of non-small cell lung cancer, here, we identify the FOXO3 gene as a novel target of deletion in human lung adenocarcinoma (LAC). Biallelic or homozygous deletion (HD) of FOXO3 was detected in 8 of 33 (24.2%) mostly early-stage LAC of smokers. Another 60.6% of these tumors had losses of FOXO3 not reaching the level of HD (hereafter referred to as sub-HD). In contrast, no HD of FOXO3 was observed in 19 lung squamous cell carcinoma. Consistent with the deletion of FOXO3 were corresponding decreases in its mRNA and protein levels in LAC. The potential role of FOXO3 loss in LAC was also investigated. The carcinogen (+)-anti-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) is strongly implicated as a cause of human lung cancer. Here, we show that FOXO3a is functionally activated and augments the level of caspase-dependent apoptosis in cells exposed to this DNA-damaging carcinogen. These results implicate FOXO3 as a suppressor of LAC carcinogenesis, a role frequently lost through gene deletion.

Purpose: It is a critical challenge to determine the risk of recurrence in early stage non-small cell lung cancer (NSCLC) patients. Accurate gene expression signatures are needed to classify patients into high- and low-risk groups to improve the selection of patients for adjuvant therapy., Experimental Design: Multiple published microarray data sets were used to evaluate our previously identified lung cancer prognostic gene signature. Expression of the signature genes was further validated with real-time reverse transcription-PCR and Western blot assays of snap-frozen lung cancer tumor tissues., Results: Our previously identified 35-gene signature stratified 264 patients with NSCLC into high- and low-risk groups with distinct overall survival rates (P < 0.05, Kaplan-Meier analysis, log-rank tests). The 35-gene signature further stratified patients with clinical stage 1A diseases into poor prognostic and good prognostic subgroups (P = 0.0007, Kaplan-Meier analysis, log-rank tests). This signature is independent of other prognostic factors for NSCLC, including age, sex, tumor differentiation, tumor grade, and tumor stage. The expression of the signature genes was validated with real-time reverse transcription-PCR analysis of lung cancer tumor specimens. Protein expression of two signature genes, TAL2 and ILF3, was confirmed in lung adenocarcinoma tumors by using Western blot analysis. These two biomarkers showed correlated mRNA and protein overexpression in lung cancer development and progression., Conclusions: The results indicate that the identified 35-gene signature is an accurate predictor of survival in NSCLC. It provides independent prognostic information in addition to traditional clinicopathologic criteria.