Molecular biology of lung cancer

Downregulation of Kruppel-like factor 2 is associated with poor prognosis for nonsmall-cell lung cancer

Kruppel-like factor 2 (KLF2) expression is diminished in many malignancies. However, its expression and role in nonsmall-cell lung cancer (NSCLC) remain unknown. In this study, we found that KLF2 levels were decreased in NSCLC tissues compared with adjacent normal tissues. Its expression level was significantly correlated with TNM stages, tumor size, and lymph node metastasis. Moreover, patients with low levels of KLF2 expression had a relatively poor prognosis. Furthermore, knockdown of KLF2 expression by siRNA could promote cell proliferation, while ectopic expression of KLF2 inhibited cell proliferation and promoted apoptosis in NSCLC cells partly via regulating CDKN1A/p21 and CDKN2B/p15 protein expression. Our findings present that decreased KLF2 could be identified as a poor prognostic biomarker in NSCLC and regulate cell proliferation and apoptosis.

Critical function for nuclear envelope protein TMEM209 in human pulmonary carcinogenesis

Therapeutic targets for more effective and less toxic treatments of lung cancer remain important. Here we report the identification of the integral nuclear envelope protein TMEM209 as a critical driver of human lung cancer growth and survival. TMEM209 expression was normally limited to testis, but we found that it was widely expressed in lung cancer, in which it localized to the nuclear envelope, Golgi apparatus, and the cytoplasm of lung cancer cells. Ectopic overexpression of TMEM209 promoted cell growth, whereas TMEM209 attenuation was sufficient to block growth. Mass spectrometric analysis identified the nucleoporin protein NUP205 as a TMEM209-interacting protein, stabilizing NUP205 and increasing the level of c-Myc in the nucleus. Taken together, our findings indicate that TMEM209 overexpression and TMEM209-NUP205 interaction are critical drivers of lung cancer proliferation, suggesting a promising new target for lung cancer therapy.

Phosphorylation and activation of cell division cycle associated 5 by mitogen-activated protein kinase play a crucial role in human lung carcinogenesis

We analyzed the gene expression profiles of clinical lung carcinomas using a cDNA microarray containing 27,648 genes or expressed sequence tags, and identified CDCA5 (cell division cycle associated 5) to be upregulated in the majority of lung cancers. Tumor tissue microarray analysis of 262 non-small cell lung cancer patients revealed that CDCA5 positivity was an independent prognostic factor for lung cancer patients. Suppression of CDCA5 expression with siRNAs inhibited the growth of lung cancer cells; concordantly, induction of exogenous expression of CDCA5 conferred growth-promoting activity in mammalian cells. We also found that extracellular signal-regulated kinase (ERK) kinase phosphorylated CDCA5 at Ser79 and Ser209 in vivo. Exogenous expression of phospho-mimicking CDCA5 protein whose Ser209 residue was replaced with glutamine acid further enhanced the growth of cancer cells. In addition, functional inhibition of the interaction between CDCA5 and ERK kinase by a cell-permeable peptide corresponding to a 20-amino-acid sequence part of CDCA5, which included the Ser209 phosphorylation site by ERK, significantly reduced phosphorylation of CDCA5 and resulted in growth suppression of lung cancer cells. Our data suggest that transactivation of CDCA5 and its phosphorylation at Ser209 by ERK play an important role in lung cancer proliferation, and that the selective suppression of the ERK-CDCA5 pathway could be a promising strategy for cancer therapy.

Activation of an oncogenic TBC1D7 (TBC1 domain family, member 7) protein in pulmonary carcinogenesis

To develop novel biomarkers and therapeutic agents for lung cancers, we screened molecules that were highly expressed in lung cancers by means of cDNA microarray analysis and found an elevated expression of TBC1 domain family, member 7 (TBC1D7) in the majority of lung cancers. Northern-blot analysis using mRNAs from 16 normal tissues detected its expression only in testis. Immunohistochemical staining using tumor tissue microarrays consisting of 261 archived non-small cell lung cancer (NSCLC) specimens suggested an association of TBC1D7 expression with poor prognosis for NSCLC patients (P = 0.0063). Treatment of lung cancer cells using siRNA against TBC1D7, suppressed its expression and resulted in inhibition of the cell growth. Furthermore, the induction of exogenous expression of TBC1D7 conferred growth-promoting activity at in vitro and in vivo conditions. We also identified TBC1D7 to interact with TSC1 protein in lung cancer cells. TSC1 introduction into cells increased the level of TBC1D7 protein, whereas knockdown of TSC1 expression decreased the level of TBC1D7 protein, suggesting that TBC1D7 is stabilized probably through interaction with TSC1. In addition, inhibition of the binding between TBC1D7 and TSC1 by a TBC1D7-derived 20-amino acid cell-permeable peptide (11R-TBC1D7(152-171)), which corresponded to the binding domain to TSC1, effectively suppressed growth of lung cancer cells. Selective suppression of TBC1D7 and/or inhibition of the TBC1D7-TSC1 complex formation could be promising therapeutic strategies for lung cancer therapy.

Circulating plasma DNA as diagnostic biomarker in non-small cell lung cancer

OBJECTIVES

The presence of circulating DNA in plasma of patients with malignant neoplasm has been a known fact for over 30 years. Since then, the concentration of free circulating plasma DNA has been studied as well as the genetic alterations and epigenetic alterations of tumour DNA of patients that suffer from various types of tumours. The analysis of circulating plasma DNA may be a useful marker to get an early diagnosis on malignant neoplasms. This study has been specifically designed to validate the quantification of circulating DNA in order to design a test useful for the early identification of non-small cell lung cancer patients and the monitoring of lung cancer progression. A second aim of this work is the sensibility and specificity evaluation of such method for future applications.

METHODS

The quantity of plasma DNA was determined using quantitative Real-Time PCR with amplification of the human telomerase reverse transcriptase (hTERT) gene in 151 patients that suffer from lung cancer and 79 healthy controls. The performance of the test was evaluated with a ROC curve. The relationship between the DNA concentration and main demographic, clinical and pathological variables was examined with logistic regression models as well as multiple linear regression models.

RESULTS

The concentration of circulating plasma DNA was about four times higher in patients with lung cancer with respect to the controls (12.8 vs 2.9 ng/mL). The area under the ROC curve was 0.79 (95% CI, 0.710-0.83). The concentration of circulating DNA proved to be an important risk factor for the presence of the illness and a prognostic index in the follow-up.

CONCLUSIONS

The use of quantitative Real-Time PCR revealed that higher values of circulating DNA can be found in patients with lung neoplasm compared to the healthy controls. This could have practical implications such as the use in screening programs and a possible prognostic significance in the follow-up.

Expression of alpha CP-4 inhibits cell cycle progression and suppresses tumorigenicity of lung cancer cells

The protein alpha CP-4 (also known as hnRNP E4) is an RNA binding protein encoded by a gene at 3p21, one of the most common altered regions in lung cancer. It has been proposed that alpha CP-4 may function as a lung tumor suppressor. Lack of alpha CP-4 expression is frequent in highly proliferative lung tumors and correlates with alpha CP-4 allele losses. The aim of this study was to evaluate the effect of alpha CP-4 on the tumorigenic capacity of lung cancer cells. alpha CP-4 expression was induced by transient transfection or stable infection with recombinant retroviruses. Induction of alpha CP-4 expression caused cell cycle arrest in G(2)/M in 3 out of the 7 lung cancer cell lines studied, while no effect on apoptosis was observed. Anchorage-independent growth and invasion capacity of H1299 cells were significantly reduced by alpha CP-4 induction. Tumorigenicity of H1299 cells in nude mice was greatly inhibited by the expression of alpha CP-4. Moreover, induction of alpha CP-4 expression in already established tumors resulted in a sudden growth arrest. Immunocytochemistry analysis of the xenograft tumors revealed an in vivo effect of alpha CP-4 on cell proliferation and no effect on apoptosis. Finally, alpha CP-4 showed a subcellular localization different from alpha CP-4a, a splice variant that does not affect cell proliferation. In conclusion, expression of alpha CP-4 can inhibit proliferation and tumorigenesis of lung cancer cells, both in vivo and in vitro, by delaying the progression of the cell cycle.

Activation of KIF4A as a prognostic biomarker and therapeutic target for lung cancer

PURPOSE AND EXPERIMENTAL DESIGN

To identify molecules that might be useful as diagnostic/prognostic biomarkers and as targets for the development of new molecular therapies, we screened genes that were highly transactivated in a large proportion of 101 lung cancers by means of a cDNA microarray representing 27,648 genes. We found a gene encoding KIF4A, a kinesin family member 4A, as one of such candidates. Tumor tissue microarray was applied to examine the expression of KIF4A protein and its clinicopathologic significance in archival non-small cell lung cancer (NSCLC) samples from 357 patients. A role of KIF4A in cancer cell growth and/or survival was examined by small interfering RNA experiments. Cellular invasive activity of KIF4A on mammalian cells was examined using Matrigel assays.

RESULTS

Immunohistochemical staining detected positive KIF4A staining in 127 (36%) of 357 NSCLCs and 19 (66%) of 29 small-cell lung cancers examined. Positive immunostaining of KIF4A protein was associated with male gender (P = 0.0287), nonadenocarcinoma histology (P = 0.0097), and shorter survival for patients with NSCLC (P = 0.0005), and multivariate analysis confirmed its independent prognostic value (P = 0.0012). Treatment of lung cancer cells with small interfering RNAs for KIF4A suppressed growth of the cancer cells. Furthermore, we found that induction of exogenous expression of KIF4A conferred cellular invasive activity on mammalian cells.

CONCLUSIONS

These data strongly implied that targeting the KIF4A molecule might hold a promise for the development of anticancer drugs and cancer vaccines as well as a prognostic biomarker in clinic.

Fibroblast growth factor receptor 1 oncogene partner as a novel prognostic biomarker and therapeutic target for lung cancer

To screen candidate molecules that might be useful as diagnostic biomarkers or for development of novel molecular-targeting therapies, we previously carried out gene-expression profile analysis of 101 lung carcinomas and detected an elevated expression of FGFR1OP (fibroblast growth factor receptor 1 oncogene partner) in the majority of lung cancers. Immunohistochemical staining using tumor tissue microarrays consisting of 372 archived non-small cell lung cancer (NSCLC) specimens revealed positive staining of FGFR1OP in 334 (89.8%) of 372 NSCLCs. We also found that the high level of FGFR1OP expression was significantly associated with shorter tumor-specific survival times (P < 0.0001 by log-rank test). Moreover, multivariate analysis determined that FGFR1OP was an independent prognostic factor for surgically treated NSCLC patients (P < 0.0001). Treatment of lung cancer cells, in which endogenous FGFR1OP was overexpressed, using FGFR1OP siRNA, suppressed its expression and resulted in inhibition of the cell growth. Furthermore, induction of FGFR1OP increased the cellular motility and growth-promoting activity of mammalian cells. To investigate its function, we searched for FGFR1OP-interacting proteins in lung cancer cells and identified ABL1 (Abelson murine leukemia viral oncogene homolog 1) and WRNIP1 (Werner helicase interacting protein 1), which was known to be involved in cell cycle progression. FGFR1OP significantly reduced ABL1-dependent phosphorylation of WRNIP1 and resulted in the promotion of cell cycle progression. Because our data imply that FGFR1OP is likely to play a significant role in lung cancer growth and progression, FGFR1OP should be useful as a prognostic biomarker and probably as a therapeutic target for lung cancer.

The neuromedin U-growth hormone secretagogue receptor 1b/neurotensin receptor 1 oncogenic signaling pathway as a therapeutic target for lung cancer

Using a genome-wide cDNA microarray to search for genes that were specifically up-regulated in non-small cell lung cancers (NSCLC), we identified an abundant expression of neuromedin U (NMU) in the great majority of lung cancers. Immunohistochemical analysis showed a significant association of NMU expression with poorer prognosis of patients with NSCLC. Treatment of NSCLC cells with short interfering RNA against NMU suppressed its expression and inhibited the growth of the cells; on the other hand, the induction of exogenous expression of NMU conferred growth-promoting activity and enhanced cell mobility in vitro. We found that two G protein-coupled receptors, growth hormone secretagogue receptor 1b and neurotensin receptor 1, were also overexpressed in NSCLC cells, and that a heterodimer complex of these receptors functioned as an NMU receptor. The NMU-receptor interaction subsequently induced the generation of a second messenger, cyclic AMP, to activate its downstream genes including transcription factors and cell cycle regulators. Treatment of NSCLC cells with short interfering RNAs for growth hormone secretagogue receptor or neurotensin receptor 1 suppressed the expression of those genes and the growth of NSCLC cells. These data strongly implied that targeting the NMU signaling pathway would be a promising therapeutic strategy for the treatment of lung cancers.

Phosphorylation and activation of cell division cycle associated 8 by aurora kinase B plays a significant role in human lung carcinogenesis

Through genome-wide gene expression analysis of lung carcinomas, we detected in the great majority of lung cancer samples cotransactivation of cell division cycle associated 8 (CDCA8) and aurora kinase B (AURKB), which were considered to be components of the vertebrate chromosomal passenger complex. Immunohistochemical analysis of lung cancer tissue microarrays showed that overexpression of CDCA8 and AURKB was significantly associated with poor prognosis of lung cancer patients. AURKB directly phosphorylated CDCA8 at Ser(154), Ser(219), Ser(275), and Thr(278) and seemed to stabilize CDCA8 protein in cancer cells. Suppression of CDCA8 expression with small interfering RNA against CDCA8 significantly suppressed the growth of lung cancer cells. In addition, functional inhibition of interaction between CDCA8 and AURKB by a cell-permeable peptide corresponding to 20-amino acid sequence of a part of CDCA8 (11R-CDCA8(261-280)), which included two phosphorylation sites by AURKB, significantly reduced phosphorylation of CDCA8 and resulted in growth suppression of lung cancer cells. Our data imply that selective suppression of the CDCA8-AURKB pathway could be a promising therapeutic strategy for treatment of lung cancer patients.

Identification of Myc-associated protein with JmjC domain as a novel therapeutic target oncogene for lung cancer

Through genome-wide expression profile analysis for non-small cell lung cancers (NSCLC), we found overexpression of a Myc-associated protein with JmjC domain (MAPJD) gene in the great majority of NSCLC cases. Induction of exogenous expression of MAPJD into NIH3T3 cells conferred growth-promoting activity. Concordantly, in vitro suppression of MAPJD expression with small interfering RNA effectively suppressed growth of NSCLC cells, in which MAPJD was overexpressed. We found four candidate MAPJD target genes, SBNO1, TGFBRAP1, RIOK1, and RASGEF1A, which were the most significantly induced by exogenous MAPJD expression. Through interaction with MYC protein, MAPJD transactivates a set of genes, including kinases and cell signal transducers that are possibly related to proliferation of lung cancer cells. As our data imply that MAPJD is a novel member of the MYC transcriptional complex and its activation is a common feature of lung cancer, selective suppression of this pathway could be a promising therapeutic target for treatment of lung cancers.

Increased Expression of Insulin-like Growth Factor-II Messenger RNA–Binding Protein 1 Is Associated with Tumor Progression in Patients with Lung Cancer

PURPOSE

To identify novel biomarkers and therapeutic targets for lung cancers, we screened for genes that were highly transactivated in a large proportion of non-small cell lung cancers (NSCLC) using a cDNA microarray representing 27,648 genes.

EXPERIMENTAL DESIGN

A gene encoding insulin-like growth factor-II mRNA-binding protein 1 (IMP-1) was selected as a candidate (> or =3-fold expression than in normal lung tissue in about 70% of NSCLCs). Tumor tissue microarray was applied to examine expression of IMP-1 protein in archival lung cancer samples from 267 patients and investigated its clinicopathologic significance. A role of IMP-1 in cancer cell growth and/or survival was examined by small interfering RNA experiments. Cellular invasive activity of IMP-1 on mammalian cells was examined using Matrigel assays. mRNAs associated with IMP-1 in cancer cells were also isolated by RNA immunoprecipitation followed by cDNA microarray analysis.

RESULTS

Positive immunostaining of IMP-1 was correlated with male (P = 0.0001), tumor size (P = 0.0003), non-adenocarcinoma histology (P < 0.0001), smoking history (P = 0.0005), non-well-differentiated tumor grade (P = 0.0001), and poor prognosis (P = 0.0053). Suppression of IMP-1 expression with small interfering RNA effectively suppressed growth of NSCLC cells. In addition, we identified that exogenous expression of IMP-1 increased the migratory activity of mammalian cells. IMP-1 was able to bind to mRNAs encoding a variety of proteins involved in signal transduction, cell cycle progression, cell adhesion and cytoskeleton, and various types of enzymatic activities.

CONCLUSIONS

These results suggest that IMP-1 expression is likely to play important roles in lung cancer development and progression, and that IMP-1 is a prognostic biomarker and a promising therapeutic target for lung cancer.

Activation of CDCA1-KNTC2, members of centromere protein complex, involved in pulmonary carcinogenesis

We found cotransactivation of cell division associated 1 (CDCA1) and kinetochore associated 2 (KNTC2), members of the evolutionarily conserved centromere protein complex, in non-small cell lung carcinomas (NSCLC). Immunohistochemical analysis using lung cancer tissue microarray confirmed high levels of CDCA1 and KNTC2 proteins in the great majority of lung cancers of various histologic types. Their elevated expressions were associated with poorer prognosis of NSCLC patients. Knockdown of either CDCA1 or KNTC2 expression with small interfering RNA significantly suppressed growth of NSCLC cells. Furthermore, inhibition of their binding by a cell-permeable peptide carrying the CDCA1-derived 19-amino-acid peptide (11R-CDCA1(398-416)) that correspond to the binding domain to KNTC2 effectively suppressed growth of NSCLC cells. As our data imply that human CDCA1 and KNTC2 seem to fall in the category of cancer-testis antigens, and that their simultaneous up-regulation is a frequent and important feature of cell growth/survival of lung cancer, selective suppression of CDCA1 or KNTC2 activity and/or inhibition of the CDCA1-KNTC2 complex formation could be a promising therapeutic target for treatment of lung cancers.

ANLN Plays a Critical Role in Human Lung Carcinogenesis through the Activation of RHOA and by Involvement in the Phosphoinositide 3-Kinase/AKT Pathway

Gene expression profile analysis of non-small cell lung cancers (NSCLC) and subsequent functional analyses revealed that human ANLN, a homologue of anillin, an actin-binding protein in Drosophila, was transactivated in lung cancer cells and seemed to play a significant role in pulmonary carcinogenesis. Induction of small interfering RNAs against ANLN in NSCLC cells suppressed its expression and resulted in growth suppression; moreover, treatment with small interfering RNA yielded cells with larger morphology and multiple nuclei, which subsequently died. On the other hand, induction of exogenous expression of ANLN enhanced the migrating ability of mammalian cells by interacting with RHOA, a small guanosine triphosphatase, and inducing actin stress fibers. Interestingly, inhibition of phosphoinositide 3-kinase/AKT activity in NSCLC cells decreased the stability of ANLN and caused a reduction of the nuclear ANLN level. Immunohistochemical staining of nuclear ANLN on lung cancer tissue microarrays was associated with the poor survival of NSCLC patients, indicating that this molecule might serve as a prognostic indicator. Our data imply that up-regulation of ANLN is a common feature of the carcinogenetic process in lung tissue, and suggests that selective suppression of ANLN could be a promising approach for developing a new strategy to treat lung cancers.

A novel human tRNA-dihydrouridine synthase involved in pulmonary carcinogenesis

An increased level of dihydrouridine in tRNA(Phe) was found in human malignant tissues nearly three decades ago, but its biological significance in carcinogenesis has remained unclear. Through analysis of genome-wide gene-expression profiles among non-small cell lung carcinomas (NSCLC), we identified overexpression of a novel human gene, termed hDUS2, encoding a protein that shared structural features with tRNA-dihydrouridine synthases (DUS). The deduced 493-amino-acid sequence showed 39% homology to the dihydrouridine synthase 2 enzyme (Dus2) of Saccharomyces cerevisiae and contained a conserved double-strand RNA-binding motif (DSRM). We found that hDUS2 protein had tRNA-DUS activity and that it physically interacted with EPRS, a glutamyl-prolyl tRNA synthetase, and was likely to enhance translational efficiencies. A small interfering RNA against hDUS2 transfected into NSCLC cells suppressed expression of the gene, reduced the amount of dihydrouridine in tRNA molecules, and suppressed growth. Immunohistochemical analysis showed significant association between higher levels of hDUS2 in tumors and poorer prognosis of lung cancer patients. Our data imply that up-regulation of hDUS2 is a relatively common feature of pulmonary carcinogenesis and that selective suppression of hDUS2 enzyme activity and/or inhibition of formation of the hDUS2-tRNA synthetase complex could be a promising therapeutic strategy for treatment of many lung cancers.

Plakophilin 3 Oncogene as Prognostic Marker and Therapeutic Target for Lung Cancer

We investigated gene expression profiles of non-small cell lung carcinomas (NSCLC) to screen candidate molecules that might be useful as diagnostic markers or for development of novel molecular-targeting therapies. Here we report evidence that a member of the armadillo protein family, plakophilin 3 (PKP3), is a potential molecular target for treatment of lung cancers and might also serve as a prognostic indicator. We documented elevated expression of PKP3 in the great majority of NSCLC samples examined. Treatment of NSCLC cells with small interfering RNAs of PKP3 suppressed growth of the cancer cells; on the other hand, induction of exogenous expression of PKP3 conferred growth-promoting activity on COS-7 cells and enhanced their mobility in vitro. To investigate its function, we searched for PKP3-interacting proteins and identified dynamin 1-like, which was also activated in NSCLC. In addition, a high level of PKP3 expression was associated with poor survival as well as disease stage and node status for patients with lung adenocarcinoma, suggesting an important role of the protein in development and progression of this disease. As our data imply that up-regulation of PKP3 is a frequent and important feature of lung carcinogenesis, we suggest that targeting the PKP3 molecule might hold promise for development of a new therapeutic and diagnostic strategy for clinical management of lung cancers.

Classification of individual lung cancer cell lines based on DNA methylation markers: use of linear discriminant analysis and artificial neural networks

The classification of small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) can pose diagnostic problems due to inter-observer variability and other limitations of histopathology. There is an interest in developing classificatory models of lung neoplasms based on the analysis of multivariate molecular data with statistical methods and/or neural networks. DNA methylation levels at 20 loci were measured in 41 SCLC and 46 NSCLC cell lines with the quantitative real-time PCR method MethyLight. The data were analyzed with artificial neural networks (ANN) and linear discriminant analysis (LDA) to classify the cell lines into SCLC or into NSCLC. Models used either data from all 20 loci, or from five significant DNA methylation loci that were selected by a step-wise back-propagation procedure (PTGS2, CALCA, MTHFR, ESR1, and CDKN2A). The data were sorted randomly by cell line into 10 different data sets, each with training and testing subsets composed of 71 and 16 of the cases, respectively. Ten ANN models were trained using the 10 data sets: five using 20 variables, and five using the five variables selected by step-wise back-propagation. The ANN models with 20 input variables correctly classified 100% of the cell lines, while the models with only five variables correctly classified 87 to 100% of cases. For comparison, 10 different LDA models were trained and tested using the same data sets with either the original data or with logarithmically transformed data. Again, half of the models used all 20 variables while the others used only the five significant variables. LDA models provided correct classifications in 62.5% to 87.5% of cases. The classifications provided by all of the different models were compared with kappa statistics, yielding kappa values ranging from 0.25 to 1.0. We conclude that ANN models based on DNA methylation profiles can objectively classify SCLC and NSCLC cells lines with substantial to perfect concordance, while LDA models based on DNA methylation profiles provide poor to substantial concordance. Our work supports the promise of ANN analysis of DNA methylation data as a powerful approach for the development of automated methods for lung cancer classification.

Genetic alteration and gene expression modulation during cancer progression

Cancer progresses through a series of histopathological stages. Progression is thought to be driven by the accumulation of genetic alterations and consequently gene expression pattern changes. The identification of genes and pathways involved will not only enhance our understanding of the biology of this process, it will also provide new targets for early diagnosis and facilitate treatment design. Genomic approaches have proven to be effective in detecting chromosomal alterations and identifying genes disrupted in cancer. Gene expression profiling has led to the subclassification of tumors. In this article, we will describe the current technologies used in cancer gene discovery, the model systems used to validate the significance of the genes and pathways, and some of the genes and pathways implicated in the progression of preneoplastic and early stage cancer.

WIF1, a component of the Wnt pathway, is down-regulated in prostate, breast, lung, and bladder cancer

To detect novel Wnt-pathway genes involved in tumourigenesis, this study analysed the RNA expression levels of 40 genes of the Wnt pathway by chip hybridization of microdissected matched pairs of 54 primary prostate carcinomas. Eleven genes showed greater than two-fold differential expression in at least 10% of prostate cancers. Three of these genes encode extracellular components of the Wnt pathway (WNT2, WIF1, SFRP4); two are receptors (FZD4, FZD6); two belong to the intracellular signal cascade (DVL1, PPP2CB); one regulates transcription (TCF4); and three represent genes regulated by this pathway (CCND2, CD44, MYC). While SFRP4, FZD4, FZD6, DVL1, TCF4, and MYC are up-regulated, WIF1, WNT2, PPP2CB, CCND2, and CD44 are down-regulated in certain prostate cancer patients. Wnt inhibitory factor 1 (WIF1) and secreted frizzled related protein (SFRP4) showed the most significant aberrant expression at the RNA level. WIF1 was down-regulated in 64% of primary prostate cancers, while SFRP4 was up-regulated in 81% of the patients. Immunohistochemical analysis using a polyclonal antibody revealed strong cytoplasmic perinuclear WIF1 expression in normal epithelial cells of the prostate, breast, lung, and urinary bladder. Strong reduction of WIF1 protein expression was found in 23% of prostate carcinomas, but also in 60% of breast, 75% of non-small cell lung (NSCLC), and 26% of bladder cancers analysed. No significant association between WIF1 down-regulation and tumour stage or grade was observed for prostate, breast or non-small cell lung carcinomas, indicating that loss of WIF1 expression may be an early event in tumourigenesis in these tissues. However, down-regulation of WIF1 correlated with higher tumour stage in urinary bladder tumours (pTa versus pT1-pT4; p = 0.038).

Expression profiles of non-small cell lung cancers on cDNA microarrays: identification of genes for prediction of lymph-node metastasis and sensitivity to anti-cancer drugs

To investigate genes involved in pulmonary carcinogenesis and those related to sensitivity of nonsmall cell lung cancers (NSCLCs) to therapeutic drugs, we performed cDNA microarray analysis of 37 NSCLCs after laser-capture microdissection of cancer cells from primary tumors. A clustering algorithm applied to the expression data easily distinguished two major histological types of non-small cell lung cancer, adenocarcinoma and squamous cell carcinoma. Subsequent analysis of the 18 adenocarcinomas identified 40 genes whose expression levels could separate cases with lymph-node metastasis from those without metastasis. In addition, we compared the expression data with measurements of the sensitivity of surgically dissected NSCLC specimens to six anti-cancer drugs (docetaxel, paclitaxel, irinotecan, cisplatin, gemcitabine, and vinorelbine), as measured by the CD-DST (collagen gel droplet embedded culture-drug sensitivity test) method. We found significant associations between expression levels of dozens of genes and chemosensitivity of NSCLCs. Our results provide valuable information for eventually identifying predictive markers and novel therapeutic target molecules for this type of cancer.

p53 and Bcl-2 Protein Expression and Its Relationship with Prognosis in Small-Cell Lung Cancer

Small-cell lung cancer (SCLC) has a poor prognosis despite good initial response to chemotherapy. Therefore, it is important to identify molecular markers that might influence survival and serve as potential therapeutic targets. Previous studies have demonstrated immunohistochemical expression of p53 and Bcl-2 in approximately 40%-90% and 55%-90% of patients with SCLC, respectively, but its relationship with prognosis remains controversial. To determine the correlation between the expression of p53 and Bcl-2 and disease-free survival, age (< 70 vs. >or= 70 years), sex, clinical stage (limited vs. extensive), performance status (World Health Organization stages 0-4), and weight loss (10% of body weight), we retrospectively studied 58 SCLC parafin sections of transbronchial biopsy specimens immunostained using monoclonal antibody against N-terminus of the human p53 protein and monoclonal antibody against Bcl-2 oncoprotein. p53 and Bcl-2 expression were observed in 41% and 57% of patients, respectively. p53 and Bcl-2 expression were not correlated with disease-free survival. There was also no correlation of p53 and Bcl-2 expression with age, sex, weight loss, and performance status. There was a significant correlation of p53 (P < 0.001) and Bcl-2 (P < 0.045) expressions with limited-stage disease.