Differentiated embryo chondrocyte plays a crucial role in DNA damage response via transcriptional regulation under hypoxic conditions.

Tumor hypoxia contributes to a biologically aggressive phenotype and therapeutic resistance. Recent studies have revealed that hypoxia reduces expression of several DNA damage recognition and repair (DRR) genes via both hypoxia-inducible factor (HIF)-independent and -dependent pathways, and this induced genomic instability in cancer cells. We show here that one of the HIF-target genes-differentiated embryo chondrocyte (DEC)-plays a role in DNA damage response via transcriptional repression. Comprehensive gene expression and database analyses have revealed systemic repression of DNA-DRR genes in cancer and non-cancer cells under hypoxic conditions. Hypoxic repression in typical cases was confirmed by quantitative RT-PCR and promoter reporter experiments, and knockdown experiments indicated the critical role of DEC2 in such repression. Assessment of histone H2AX phosphorylation revealed that recognition and repair of DNA double-strand breaks (DSBs) induced by bleomycin or γ-ray irradiation were attenuated; moreover, Cleaved Caspase-3 levels were decreased with pre-conditioning under hypoxia: opposing phenomena were ascertained by knockdown of DEC2. Finally, pre-conditioning under hypoxia decreased the sensitivity of cancer cells to DSBs, and knockdown of DEC2 increased γ-ray sensitivity. These data imply that a critical reduction of DNA-DRR occurs via DEC-dependent transcriptional repression and suggest that DEC is a potential molecular target for anti-cancer strategies.

The A Allele at rs13419896 of EPAS1 Is Associated with Enhanced Expression and Poor Prognosis for Non-Small Cell Lung Cancer.

Hypoxia-inducible factor-2α (HIF-2α, or EPAS1) is important for cancer progression, and is a putative biomarker for poor prognosis for non-small cell lung cancer (NSCLC). However, molecular mechanisms underlying the EPAS1 overexpression are not still fully understood. We explored a role of a single nucleotide polymorphism (SNP), rs13419896 located within intron 1 of the EPAS1 gene in regulation of its expression. Bioinformatic analyses suggested that a region including the rs13419896 SNP plays a role in regulation of the EPAS1 gene expression and the SNP alters the binding activity of transcription factors. In vitro analyses demonstrated that a fragment containing the SNP locus function as a regulatory region and that a fragment with A allele showed higher transactivation activity than one with G, especially in the presence of overexpressed c-Fos or c-Jun. Moreover, NSCLC patients with the A allele showed poorer prognosis than those with G at the SNP even after adjustment with various variables. In conclusion, the genetic polymorphism of the EPAS1 gene may lead to variation of its gene expression levels to drive progression of the cancer and serve as a prognostic marker for NSCLC.

Association of EPAS1 gene rs4953354 polymorphism with susceptibility to lung adenocarcinoma in female Japanese non-smokers.

INTRODUCTION: Hypoxia-inducible factor-2α (also called endothelial periodic acid-Schiff domain protein 1 [EPAS1]) seems to play an important role in some carcinogenesis, though there is no information on the relationship between single nucleotide polymorphism of EPAS1 and lung cancer development. The aim of this study was to explore a possible association of the EPAS1 gene rs4953354 polymorphism with susceptibility to lung cancer. METHODS: A case-control study of 346 patients with non-small-cell lung carcinoma (adenocarcinoma = 249, squamous cell carcinoma = 97) and 247 healthy control subjects was carried out. A/G polymorphism within an intron 2 of the EPAS1 (rs4953354) was determined by direct sequencing. RESULTS: A frequency of lung adenocarcinoma patients with a minor allele G (A/G or G/G genotype) at the rs4953354 was much higher than that of controls (odds ratio, 1.800; 95% confidence interval, 1.161-2.791; p = 0.008). This association was more evident when analyzed using female never-smokers (odds ratio, 3.31; 95% confidence interval, 1.21-9.01; p = 0.017). Mutations in epidermal growth factor receptor tended to be frequent in patients with G allele at the rs4953354, compared with those with other genotypes. CONCLUSION: The EPAS1 rs4953354 may be a potentially susceptible marker for development of lung adenocarcinoma, especially in female never-smokers.

Clinical features of ATRX or DAXX mutated neuroblastoma.

PURPOSE: Previously, we reported that alternative lengthening of telomere (ALT) may be a biomarker for chemo-sensitivity and late recurrence in neuroblastoma (NBL). In this study, alterations of ATRX or DAXX, which both encode chromatin remodeling proteins in telomeric region, and their relationship to ALT were examined in NBLs. METHODS: Our previous report on 121 NBLs revealed 11 NBLs with elongated telomeres by ALT. In these NBLs, ATRX or DAXX gene alterations were identified using next-generation sequencing and compared to clinical and other biological factors. RESULTS: In 11 ALT cases, DAXX mutations were detected in one case, and ATRX alterations were detected in 10 cases. Except for one case, no DAXX or ATRX alterations were detected in 110 tumors with normal or shortened telomeres. MYCN amplification was not detected in ATRX altered tumors. In ALT cases, three infants showed ATRX deletions, and all seven cases detected after 18months of age showed poor prognosis. CONCLUSIONS: In NBLs, ALT was caused by ATRX or DAXX alterations. ATRX altered cases without MYCN amplification detected at greater than 18months showed poor prognosis, suggesting that ATRX or DAXX alterations are a particular NBL subtype. Since these tumors showed chemo-resistance and late recurrence, complete resection in a surgical approach should be performed to improve patient prognosis.

Genetic variations in detoxification enzymes and HIF-1α in Japanese patients with COPD.

INTRODUCTION: Genetic factors contribute as major determinants in the pathophysiological mechanisms of chronic obstructive pulmonary disease (COPD). Therefore, identification of candidate genes and various gene polymorphisms have improved our understanding of COPD. OBJECTIVES: Clarify the genes, including HIF1A, that contribute to the development of COPD. METHODS: We compared the genotype frequencies of 12 polymorphisms in seven detoxification-related genes (GSTM1, GSTT1, GSTP1 exon 5, CYP1A1 exon 7, CYP1A1 3'-flanking, CYP2E1 intron 6, CYP2E1 5'-flanking, EPHX1 exon 3, EPHX1 exon 4 and HMOX1 promoter) and the hypoxia-related HIF1A (C1772T and G1790A) genes between 48 Japanese patients with work-related COPD who had a working history in a poison gas factory during World War II and two control groups (n=172 and 110 subjects, respectively). RESULTS: As expected, wild homozygotes for GSTP1 Ile105Val and EPHX1 slow/very slow phenotypes were associated with susceptibility (P=0.031) and severity (P=0.036) of COPD, respectively. Moreover, compound heterozygosity of transcription-activating HIF1A polymorphisms was observed in two patients with COPD, but not in control individuals (P=0.091). CONCLUSION: This is the first report that examined HIF1A polymorphisms in COPD and demonstrated a possible role of HIF-1α in COPD, as well as GSTP1 and EPHX1.

TMEM158 and FBLP1 as novel marker genes of cisplatin sensitivity in non-small cell lung cancer cells.

Even after development of molecular targeting therapies, platinum-based chemotherapy is still a standard care for treatment of locally advanced non-small cell lung cancer (NSCLC). So far, critical molecular markers capable to predict the therapeutic response in NSCLC patients remain undetermined. We here attempted to identify novel biomarker genes for cisplatin (CDDP) for a tailored therapy. Initial screening to explorer association of IC(50) values of CDDP obtained by MTT assay and gene expression levels measured with oligonucleotide microarray and real-time RT-PCR provided 6 candidate genes, namely, NUBPL, C9orf30, ZNF12, TMEM158, GSK3B, and FBLP1 using 9 lung cancer cells consisting of 3 small and 6 NSCLC cells. These 6 genes together with 5 reported biomarkers, i.e., GSTP1, ERCC1, BRCA1, FRAP1, and RRM1, were subjected to a linear regression analysis using 12 NSCLC cell lines including 6 additional NSCLC cells: only FBLP1 and TMEM158 genes showed positive associations with statistical significances (P = .016 and .026, respectively). The biological significance of these genes was explored by in vitro experiments: Knockdown experiments in PC-9/CDDP cells revealed that the reduced expression of TMEM158 significantly decreased the chemo-resistance against CDDP (P <.0001), while 2 transformants of PC-6 cells stably over-expressing FBLP1 resulted in an enhanced resistance to CDDP (P = .004 and P = .001). Furthermore, a stepwise multiple regression analysis demonstrated the best prediction formula could be fixed when we used expression data of TMEM158 and FBLP1 (R(2) = 0.755, P = .0018). TMEM158 and FBLP1 may be powerful predictive biomarkers for CDDP therapy in NSCLC.

Neoplastic transformation by TERT in FGF-2-expanded human mesenchymal stem cells.

The low percentage of human mesenchymal stem cells (hMSCs) in bone marrow necessitates their in vitro expansion prior to clinical use in regenerative medicine. We evaluated the effect of long-term culture of hMSCs on telomere length and transformation capacity by TERT transfection. hMSCs were isolated from the bone marrow aspirates of 24 donors and cultured with fibroblast growth factor-2 (FGF-2). Six cell lines with >500 population doubling levels were considered immortalized. TERT was transfected into two of the six lines for a comparison of telomere length, telomerase activity, differential capacity, colony formation capacity in soft agar and tumorigenicity in immunodeficient (NOD-SCID) mice. hMSC lines exhibited elongated telomeres without the activation of telomerase and retained multi-lineage differentiation potential upon chondrogenic or adipogenic differentiation, while non-immortalized hMSCs showed a marked reduction in telomere length in the differentiation process. Immortalized hMSCs showed anchorage-independence and formed tumors in NOD-SCID mice. Histologically, these tumors consisted of differentiated cells such as fat tissue and cartilage. Two TERT-transfected hMSC lines showed high rates of tumor formation in NOD-SCID mice. These tumors were histologically similar to teratocarcinoma without differentiated cells. These cells may provide a model for the origin of cancer stem cells from adult stem cells, and indicate the possibility that telomerase activation has a major role in the malignant transformation of human stem cells. These data suggest that adult hMSCs have a potential for neoplastic transformation and have implications for the use of hMSCs in tissue engineering and regenerative medicine.

Hypoxia-inducible factor-1α polymorphisms are associated with genetic aberrations in lung cancer.

BACKGROUND AND OBJECTIVE: The transcription factor, hypoxia-inducible factor-1 (HIF-1), is a master regulator of hypoxia, including repression of DNA repair systems, resulting in genomic instability in cancer cells. The roles of the polymorphic HIF-1α variants, C1772T (P582S) and G1790A (A588T), which are known to enhance transcriptional activity, were evaluated in lung cancers. METHODS: HIF-1α polymorphisms were assessed by direct sequencing in a total of 83 lung cancer patients (42 adenocarcinomas, 30 squamous cell, four adenosquamous cell and seven small cell lung carcinomas) and in 110 healthy control subjects. The relationship between these polymorphisms and the frequently observed genetic and/or epigenetic aberrations, TP53 loss of heterozygosity (LOH), 1p34 LOH, retinoblastoma-1 (RB1) LOH, p16 inactivation and epidermal growth factor receptor aberrations, was then assessed. RESULTS: There were no significant differences in genotype frequencies for either C1772T or G1790A between lung cancer patients and healthy controls. However, the frequency of the HIF1A C1772T variant allele was significantly higher in lung cancer patients with TP53 LOH (P = 0.015). Among adenocarcinoma patients, individuals with variant alleles of either polymorphism showed significantly higher frequencies of TP53 LOH (P = 0.047), 1p34 LOH (P = 0.009), or either of these (P = 0.008) in the tumours. The in vitro transcriptional activity of these HIF1A variants in A549 lung cancer cells was significantly greater than that of the wild type under either normoxic or hypoxic conditions, especially for P582S in cells containing mutant p53 (P < 0.0005 and P < 0.005, respectively). CONCLUSIONS: These findings indicate that functional polymorphisms in the HIF-1α gene may have an important impact on lung carcinogenesis, especially in adenocarcinomas, possibly by increasing genomic instability.

Telomerase activation without shortening of telomeric 3'-overhang is a poor prognostic factor in human colorectal cancer.

Our previous report demonstrated a good correlation between high telomerase activity of cancer tissues and a poor prognosis of patients with colorectal cancers, except for several cases. To elucidate the additional factors that contribute to patient prognosis, the correlation among the expression levels of telomere binding proteins (TBP), the lengths of telomeres, the lengths of telomere 3'-overhang (3'-OH) and telomerase activity in 106 paired colorectal cancer and corresponding noncancerous mucosa (NCM) specimens were examined. The expression levels of eight TBP genes (TRF1, TRF2, TIN2, TANK1, TANK2, POT1, RAP1 and TPP1) were analyzed. Among the 106 cases, 35 cases had shortened telomeres (<7 kb), 15 had shortened 3'-OH (3'-OH length ratio of cancer/NCM <0.5) and 88 were classified as telomerase-activated cancers (activity ratio of cancer/NCM >2). Comparison between NCM and cancer in each case showed that all TBP except for POT1 were downregulated in cancers. A survival analysis using a Cox proportional hazard model showed that the survival rate of the telomerase-activated cases with shortened 3'-OH and that of telomerase-inactivated cases were significantly better than that of telomerase-activated cases without 3'-OH shortening, that is, restored or maintained 3'-OH (P = 0.018). In the telomerase-activated cancers, the length of 3'-OH was significantly correlated with the expression levels of POT1. Elongation of telomeric overhang by telomerase, which might be regulated by POT1, may contribute to the increase of malignant potential in colorectal cancers.

A robust method for estimating gene expression states using Affymetrix microarray probe level data.

BACKGROUND: Microarray technology is a high-throughput method for measuring the expression levels of thousand of genes simultaneously. The observed intensities combine a non-specific binding, which is a major disadvantage with microarray data. The Affymetrix GeneChip assigned a mismatch (MM) probe with the intention of measuring non-specific binding, but various opinions exist regarding usefulness of MM measures. It should be noted that not all observed intensities are associated with expressed genes and many of those are associated with unexpressed genes, of which measured values express mere noise due to non-specific binding, cross-hybridization, or stray signals. The implicit assumption that all genes are expressed leads to poor performance of microarray data analyses. We assume two functional states of a gene - expressed or unexpressed - and propose a robust method to estimate gene expression states using an order relationship between PM and MM measures. RESULTS: An indicator 'probability of a gene being expressed' was obtained using the number of probe pairs within a probe set where the PM measure exceeds the MM measure. We examined the validity of the proposed indicator using Human Genome U95 data sets provided by Affymetrix. The usefulness of 'probability of a gene being expressed' is illustrated through an exploration of candidate genes involved in neuroblastoma prognosis. We identified the candidate genes for which expression states differed (un-expressed or expressed) when compared between two outcomes. The validity of this result was subsequently confirmed by quantitative RT-PCR. CONCLUSION: The proposed qualitative evaluation, 'probability of a gene being expressed', is a useful indicator for improving microarray data analysis. It is useful to reduce the number of false discoveries. Expression states - expressed or unexpressed - correspond to the most fundamental gene function 'On' and 'Off', which can lead to biologically meaningful results.

Carcinogenesis and cellular immortalization without persistent inactivation of p16/Rb pathway in lung cancer.

Existence of cancer stem cells (CSCs) is still hypothetical and their practical marker is not available yet in lung cancer. To verify the possible existence of CSCs and to find their markers in lung cancer, we compared the p16/Rb and telomerase status in 83 lung cancer tissues and 15 lung cancer cell lines, since inactivation of p16/Rb pathway is considered to be a prerequisite for normal somatic cells to become immortal cancer cells. We found that 7 of 14 adenocarcinoma, but not squamous cell carcinoma, tissues with high telomerase activity and 3 adenocarcinoma cell lines likely had intact p16/Rb. Such cell lines showed higher colony formation capacity in soft agar compared with inactivated ones with similar growth rate. Moreover, cisplatin-resistant cell line PC9/CDDP with intact p16/Rb, but not PC14/CDDP with its inactivation, increased the colony formation capacity compared with the parent cells. Since CSCs are considered to be resistant to conventional anticancer drugs, they could have been concentrated as long as CSCs existed. We propose that half of immortal lung adenocarcinomas are derived from innately telomerase-positive stem cells, which might be the origin of CSCs, and that high telomerase activity with intact p16/Rb could be a marker of stem cell origin.

Activation of the hypoxia-inducible factor-1 in overloaded temporomandibular joint, and induction of osteoclastogenesis.

Vascular endothelial growth factor (Vegf) was previously shown to be expressed specifically in the condylar cartilage of temporomandibular joint-osteoarthritis (TMJ-OA) model rats. Here we demonstrate for the first time that hypoxia-inducible factor-1alpha (Hif-1alpha) is activated in mature chondrocytes of temporomandibular joint-osteoarthritis (TMJ-OA) model rat by mechanical overload, and that activated Hif-1 in chondrocytes can induce osteoclastogenesis via repression of osteoprotegerin (Opg) expression. In rat TMJs, degeneration of the condylar cartilage became prominent in proportion to the duration of overloading. Hif-1alpha expression was observed specifically in mature and hypertrophic chondrocytes, and Hif-1alpha-positivity, level of Vegf expression, and tartrate-resistant acid phosphatase (TRAP)-positive cell numbers all increased in the same manner. When ATDC5 cells induced differentiation by insulin were cultured under hypoxia, Hif-1alpha induction was observed in mature stage, but not in immature stage. Inductions of Hif-1-target genes showed a similar expression pattern. In addition, expression of Opg decreased in hypoxia, and Hif-1alpha played a role, in part, in its regulation.

Mydriasis associated with local dysfunction of parasympathetic nerves in two dogs.

In clinical practice, photophobia resulting from persistent mydriasis may be associated with dysfunction of ocular parasympathetic nerves or primary iris lesions. We encountered a 5-year-old Miniature Dachshund and a 7-year-old Shih Tzu with mydriasis, abnormal pupillary light reflexes, and photophobia. Except for sustained mydriasis and photophobia, no abnormalities were detected on general physical examination or ocular examination of either dog. We performed pharmacological examinations using 0.1% and 2% pilocarpine to evaluate and diagnose parasympathetic denervation of the affected pupillary sphincter muscles. On the basis of the results, we diagnosed a pupillary abnormality due to parasympathetic dysfunction and not to overt primary iris lesions. The test revealed that neuroanatomic localization of the lesion was postciliary ganglionic in the first dog.

Telomere biology in neuroblastoma: telomere binding proteins and alternative strengthening of telomeres.

PURPOSE: Neuroblastoma (NBL) shows remarkable biologic heterogeneity, resulting in favorable or unfavorable prognoses. Previously, we reported that most unfavorable NBLs express high telomerase activity to maintain telomere length. Recently, telomere binding proteins (TBPs) and alternative lengthening of telomeres (ALTs) have been identified as key factors of telomere maintenance. METHODS: To evaluate the correlation between telomerase activity, telomere length, and the expression levels of TBPs in NBL, we analyzed and quantified these factors in 121 untreated NBLs. RESULTS: Shortened and elongated telomeres were detected in 21 (17.3%) and 11 cases (9.0%), respectively, and there was a significant correlation between telomere length and the length of the 3'-overhang. The tumors with shortened or elongated telomeres showed significant lower expression of TBPs, except for RAP1. Although telomerase activity did not correlate with telomere length, 16 of 22 cases with high telomerase activity and 5 of 9 cases (ALT tumors) that showed long telomeres without high telomerase activity resulted in death. High-dose chemotherapy did not have much effect on these deceased ALT cases, but their survival periods were more than 2 years and relatively long compared with the deceased cases with nonelongated telomeres, suggesting that chemoresistance in ALT tumors may be related to slow growth rates. CONCLUSIONS: High telomerase activity is a poor prognostic factor in NBL. In the cases without high telomerase activity, those with elongated telomere also showed poor outcomes because of chemoresistance. Therefore, ALT and TBPs may be biomarkers for chemosensitivity in NBL. Thus, a better understanding of telomere biology may help define the characteristics of individual NBLs.

Evaluation of genes identified by microarray analysis in favorable neuroblastoma.

PURPOSE: The biological heterogeneity of neuroblastoma results in a varied outcome ranging from spontaneous regression to fatal tumor progression. Microarray expression profiling and genetic polymorphism arrays may help identify key genes that differ in aggressive neuroblastomas from those observed in tumors associated with a favorable outcome. METHODS: Total RNA was extracted from 16 neuroblastomas obtained from patients who subsequently died of the disease and from 16 favorable neuroblastomas and analyzed using a human whole genome oligomicroarray (55K CodeLink). Genes overexpressed in favorable tumors were subsequently analyzed in 121 neuroblastoma tumors obtained before chemotherapy using real-time RT-PCR. And among these cases, expression levels of these genes were also analyzed in 20 tumors obtained after chemotherapy. RESULTS: Oligomicroarray analysis revealed the overexpression of 283 genes in favorable tumors that were associated with either regressing or maturing tumors. Three candidate genes, including DHRS3, NROB1, and CYP26A1, were selected that were significantly overexpressed in favorable tumors by quantitative real-time RT-PCR (P < 0.01). No cases with overexpression of all three genes showed poor outcomes. In 20 post-chemotherapeutic tumors, the expression levels of these genes increased in the cases where patients survived but decreased in the fatal cases. CONCLUSIONS: Using microarray expression profiling, we identified genes that exhibit altered gene expression in neuroblastoma tumors associated with a favorable outcome. These candidates warrant further study for use in risk assessment and/or as therapeutic targets in neuroblastoma.

EMP3 as a candidate tumor suppressor gene for solid tumors.

BACKGROUND: Epithelial membrane protein 3 (EMP3), was recently reported to be a tumor suppressor gene for several solid tumors, and is drawing attention as a novel prognostic marker, since its expression level or hypermethylation of the promoter region is associated with clinical prognosis in neuroblastoma and esophageal cancer. However, some controversial data were also observed in gliomas and breast cancers, and there seems to be more than deletion/hypermethylation to its silencing mechanisms. OBJECTIVE: To clarify the discrepancies in the biological behavior of EMP3 among the different organ-derived malignancies or histologies and validate the potential of EMP3 as a tumor suppressor for solid tumors. METHODS: Literature dealing with EMP3 in the PubMed database was reviewed. RESULTS/CONCLUSIONS: EMP3 is a novel tumor suppressor gene in some kinds of malignancies, but not all, at the step of cellular immortalization rather than carcinogenesis. It may become a potent prognostic marker and a therapeutic target in such tumors.

Detection of CpG island hypermethylation of caspase-8 in neuroblastoma using an oligonucleotide array.

BACKGROUND: The caspase-8 gene (CASP8) is frequently inactivated in unfavorable neuroblastomas through DNA methylation. The present study utilized oligoarrays to evaluate the methylation status of a CpG island located between exons 2 and 3 of caspase 8 in neuroblastomas. PROCEDURE: DNA derived from 70 neuroblastomas was amplified by PCR after bisulfate modification and subjected to analysis on a self-made oligoarray that utilized a polycarbodiimide-coated slide to detect methylation of six intragenic CpG islands of caspase 8. In 30 cases, the methylation status was also analyzed by sequencing. In six cases, the PCR product was cloned into a vector and analyzed. RESULTS: Among the 70 tumor-derived DNAs, methylation was not detected in 18 cases, one methylated CpG was found in 12 cases, two in 18 cases, three in 3 cases, four in 8 cases, five in 1 case and six in 10 cases. All methylated CpG loci detected by sequencing were detected by oligoarray, but some methylated CpGs in three loci were detected by oligoarray alone. In these discrepant loci, methylation was detected in some clones after subcloning, indicating that the oligoarray might be more sensitive than sequencing. The CASP8 expression level was depressed in the tumors having two distinct CpG doublets. These results were significantly correlated with MYCN amplification and with clinical outcomes. CONCLUSIONS: A significant difference in the methylation status within the CpG island of CASP8 was shown between favorable and unfavorable subtypes, and CASP8 methylation detected by oligoarray may be useful in the clinical evaluation of neuroblastomas.