We identified a novel gene HJURP (Holliday junctionrecognizing protein) whose activation seemed to play a pivotal role in the immortality of cancer cells. HJURP was considered a possible downstream target for ataxia telangiectasia mutated signaling, and its expression was increased by DNA double-strand breaks (DSB). HJURP was involved in the homologous recombination pathway in the DSB repair process through interaction with hMSH5 and NBS1, which is a part of the MRN protein complex. HJURP formed nuclear foci in cells at S phase and those subjected to DNA damage. In vitro assays implied that HJURP bound directly to the Holliday junction and rDNA arrays. Treatment of cancer cells with small interfering RNA (siRNA) against HJURP caused abnormal chromosomal fusions and led to genomic instability and senescence. In addition, HJURP overexpression was observed in a majority of lung cancers and was associated with poor prognosis as well. We suggest that HJURP is an indispensable factor for chromosomal stability in immortalized cancer cells and is a potential novel therapeutic target for the development of anticancer drugs. [Cancer Res 2007; 67(18):8544-53]

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. (Cancer Res 2005; 65(24): 11314-25)

Gene expression profile analysis of lung and esophageal carcinomas revealed that Dikkopf-1 (DKK1) was highly transactivated in the great majority of lung cancers and esophageal squamous cell carcinomas (ESCC). Immunohistochemical staining using tumor tissue microarrays consisting of 279 archived non-small cell lung cancers (NSCLC) and 280 ESCC specimens showed that a high level of DKK1 expression was associated with poor prognosis of patients with NSCLC as well as ESCC, and multivariate analysis confirmed its independent prognostic value for NSCLC. In addition, we identified that exogenous expression of DKK1 increased the migratory activity of mammalian cells, suggesting that DKK1 may play a significant role in progression of human cancer. We established an ELISA system to measure serum levels of DKK1 and found that serum DKK1 levels were significantly higher in lung and esophageal cancer patients than in healthy controls. The proportion of the DKK1-positive cases was 126 of 180 (70.0%) NSCLC, 59 of 85 (69.4%) SCLC, and 51 of 81 (63.0%) ESCC patients, whereas only 10 of 207 (4.8%) healthy volunteers were falsely diagnosed as positive. A combined ELISA assays for both DKK1 and carcinoembryonic antigen increased sensitivity and classified 82.2% of the NSCLC patients as positive whereas only 7.7% of healthy volunteers were falsely diagnosed to be positive. The use of both DKK1 and ProGRP increased sensitivity to detect SCLCs up to 89.4%, whereas false-positive rate in healthy donors was only 6.3%. Our data imply that DKK1 should be useful as a novel diagnostic/prognostic biomarker in clinic and probably as a therapeutic target for lung and esophageal cancer. [Cancer Res 2007;67(6):2517-25]

Serum levels of amphiregulin and transforming growth factor-A (TGF-A), which were identified previously to be expressed at high levels in non-small cell lung cancer (NSCLC) with poor response to gefitinib, were examined by ELISA using blood samples taken from 50 patients with advanced NSCLCs. Of 14 cases that revealed above the cutoff line for amphiregulin in serum, 12 responded poorly to gefitinib, whereas 18 of the 36 cases showing below the cutoff revealed partial response (PR) or stable disease (SD; P = 0.026). Thirteen of 15 patients who were positive for TGF-A responded poorly to gefitinib, whereas 18 of the 35 patients with negative TGF-A levels turned out to be relatively good responders (P = 0.014). Of 22 patients with positive values for either or both markers, 19 were poor responders. On the other hand, among 28 patients negative for both markers, 17 were classified into the PR or SD groups (P = 0.001). Gefitinib-treated NSCLC patients whose serum amphiregulin or TGF-A was positive showed a poorer tumor-specific survival (P = 0.037 and 0.002, respectively, by univariate analysis) compared with those whose serum amphiregulin or TGF-A concentrations were negative. Multivariate analysis showed an independent association between positivity for TGF-A and shorter survival times among NSCLC patients treated with gefitinib (P = 0.034). Amphiregulin or TGF-A positivity in NSCLC tissues was significantly higher in male, nonadenocarcinomas, and smokers. Our data suggest that the status of amphiregulin and TGF-A in serum can be an important predictor of the resistance to gefitinib among patients with advanced NSCLC. (Cancer Res 2005; 65(20): 9176-84)

Object Little is known about long-term outcomes, including tumor control and adverse radiation effects, in patients harboring vestibular schwannomas (VSs) treated with stereotactic radiosurgery > 10 years previously. The aim of this study was to confirm whether Gamma Knife surgery (GKS) for VSs continues to be safe and effective > 10 years after treatment. Methods A total of 440 patients with VS (including neurofibromatosis Type 2) treated with GKS between May 1991 and December 2000 were evaluable. Of these, 347 patients (79%) underwent GKS as an initial treatment and 93 (21%) had undergone prior resection. Three hundred fifty-eight patients (81%) had a solid tumor and 82 (19%) had a cystic tumor. The median tumor volume was 2.8 cm(3) and the median marginal dose was 12.8 Gy. Results The median follow-up period was 12.5 years. The actuarial 5- and ≥ 10-year progression-free survival was 93% and 92%, respectively. No patient developed treatment failure > 10 years after treatment. According to multivariate analysis, significant factors related to worse progression-free survival included brainstem compression with a deviation of the fourth ventricle (p < 0.0001), marginal dose ≤ 13 Gy (p = 0.01), prior treatment (p = 0.02), and female sex (p = 0.02). Of 287 patients treated at a recent optimum dose of ≤ 13 Gy, 3 (1%) developed facial palsy, including 2 with transient palsy and 1 with persistent palsy after a second GKS, and 3 (1%) developed facial numbness, including 2 with transient and 1 with persistent facial numbness. The actuarial 10-year facial nerve preservation rate was 97% in the high marginal dose group (> 13 Gy) and 100% in the low marginal dose group (≤ 13 Gy). Ten patients (2.3%) developed delayed cyst formation. One patient alone developed malignant transformation, indicating an incidence of 0.3%. Conclusions In this study GKS was a safe and effective treatment for the majority of patients followed > 10 years after treatment. Special attention should be paid to cyst formation and malignant transformation as late adverse radiation effects, although they appeared to be rare. However, it is necessary to collect further long-term follow-up data before making conclusions about the long-term safety and efficacy of GKS, especially for young patients with VSs.

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 Saccharomycescerevisiae and contained a conserved double-strand RNAbinding 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 upregulation 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. (Cancer Res 2005; 65(13): 5638-46)

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][399][400][401][402][403][404][405][406][407][408][409][410][411][412][413][414][415][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 cancertestis 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

CDC20 was a negative prognostic marker with significance in patients with resected NSCLC, particularly those with ADC histology. These results provide additional information for determining postoperative adjuvant treatment.