Biomedical subjects

Eiso Hiyama

Publications and source records attributed to Eiso Hiyama.

At least 19 recordsLinked to original sources

PubMed2026

BCL11B enhancer hijacking by t(14;16)(q32;q24) translocation defines a novel high-risk subtype of T-ALL.

The molecular classification of T-cell acute lymphoblastic leukemia (T-ALL) remains incomplete, limiting risk stratification and the development of targeted therapies. Enhancer hijacking is a critical oncogenic mechanism that deregulates proto-oncogenes by repositioning cisregulatory regions via structural variants. Here, we performed an integrated analysis of pediatric and adult T-ALL and mixed-phenotype acute leukemias (MPALs), using whole-genome and whole-transcriptome sequencing. This analysis identified a group of 14 patients with predominantly T-lineage neoplasms driven by a t(14;16)(q32;q24) translocation, harboring universal GATA3 mutations and CDKN2A/B deletions. Mechanistically, this translocation repositions the ThymoD locus downstream of BCL11B, causing monoallelic, ectopic overexpression of FENDRR and mesenchymal transcription factor genes FOXF1 and FOXC2 and activating epithelial-mesenchymal transition transcription signatures. Immunophenotypic and single-cell RNA sequencing analyses revealed marked lineage ambiguity with myeloid and B-cell differentiation potentials specific to this subtype. Furthermore, functional analyses in CD34+ cord blood cells demonstrated that FOXF1 overexpression promotes myeloid differentiation while suppressing T-cell differentiation, serving as a key factor for lineage specification. Clinically, this subtype was detected in 0.15% to 4.0% of T-ALL/MPAL cases depending on the cohort, showing a median age of 15 years and enrichment in adolescents and young adults. Importantly, patients with t(14;16)(q32;q24) have an extremely poor prognosis, showing a trend toward worse outcomes than high-risk groups such as KMT2A-rearranged early T-cell progenitor-like, SPI1-rearranged, and LMO2 γδ-like T-ALLs. The unique molecular landscape and poor prognosis of patients with the t(14;16)(q32;q24) translocation underscore the need for the development of novel subtype-specific therapeutic approaches.

Humans↗

PubMed2007

Reciprocal expression of CCAAT/enhancer binding proteins alpha and beta in hepatoblastomas and its prognostic significance.

Hepatoblastoma is one of the common pediatric solid tumors with frequent mutation of the beta-catenin gene which might be an early event of its carcinogenesis. However, the detailed molecular mechanism is still unknown. We studied the expression levels of CCAAT/enhancer binding protein alpha (C/EBPalpha) and C/EBPbeta, which regulate differentiation and growth of embryonic hepatocytes, to establish whether or not they were involved in affecting the clinical behavior of hepatoblastoma. The quantitative real-time reverse transcriptase-PCR revealed that expression of C/EBPalpha mRNA was significantly up-regulated in tumors 223% (p=0.013) as compared with that in adjacent normal livers, while expression of C/EBPbeta was down-regulated to 27% (p=0.002). Of interest, the immunohistochemical analysis showed that expression of C/EBPalpha was higher and that of C/EBPbeta lower in the poorly differentiated tumor cells than in the well-differentiated cells within the same tumor. Furthermore, high expression of C/EBPalpha (p=0.047) as well as low expression of C/EBPbeta (p=0.025) was significantly associated with poor prognosis of the patients. Cox hazard model suggested that expression of C/EBPalpha and that of C/EBPbeta were independent indicators to predict the prognosis from age but not from histology. Thus, expression of C/EBP proteins may play an important role in the genesis and clinical behavior of hepatoblastoma probably by inducing different stages of arrest of differentiation.

CCAAT-Enhancer-Binding Protein-alpha↗

PubMed2006

Pretreatment and one-shot separating analysis of whole catecholamine metabolites in plasma by using LC/MS.

Catecholamines are biogenic amines that play an important role in the nervous system. Some catecholamines have been used as tumor makers of phenochromocytoma, paraganglioma and neuroblastoma. The analysis of total catecholamine metabolites should be useful for one-shot screening of multiple aspects of diseases; however, it is difficult to do this, because the catecholamine metabolites are divided into three groups: five amines, one amino acid and three carbonic acids. Catecholamines and small molecules were separated from plasma proteins by an internal-surface reversed-phase column (protein-coated octadeyclsilica column) and were analyzed by liquid chromatography (LC)/mass spectrometry (MS) using electrospray ionization time-of-flight MS. Using a reversed-phase column and hydrophilic mobile phases, we succeeded in the separation of nine catecholamines, all of which had similar structures. These nine substances were eluted in the following order: norepinephrine, epinephrine, normetanephrine, dopamine, metanephrine, 3,4-dihydroxyphenylalanine, vanillomandelic acid, 3,4-dihydroxyphenylacetic acid and homovanillic acid. The reproducibility of this method was acceptable. The highest coefficient of variation was 7.4%. In addition, various types of compounds were separated from and detected in plasma proteins by applying LC/MS. The plasma direct injection method, which uses an internal-surface reversed-phase column and an ion-pair reagent, allowed us to separate small molecules from plasma proteins. MS detected some compounds that high-performance LC could not succeed in separating and detecting with UV detection. We think that the method can be applied to find new markers in neuroblastoma, by comparing the plasma of patients with that of normal infants. The method can be also used to help in making a diagnosis of other diseases and finding their new makers.

Catecholamines↗

PubMed2006

Single nucleotide polymorphism array analysis to predict clinical outcome in neuroblastoma patients.

PURPOSE: Neuroblastoma (NB) is a heterogeneous tumor and demonstrates favorable or unfavorable outcomes. In Japan, a nationwide NB mass screening (MS) had been performed on 6-month-old infants for approximately 20 years, which might have detected almost all NB including regressing/maturing tumors. To clarify the heterogeneity of this tumor, we examined genetic alterations in the representative cases using genomewide microarrays. METHODS: Genomic DNA was extracted from 198 NB tissue samples and paired blood samples including 76 MS-detected cases and analyzed by single nucleotide polymorphism arrays. RESULTS: The single nucleotide polymorphism array classified the genetic aberrations into 4 types: whole gain/loss type, partial gain/loss type, MYCN-amplified type, and silent type. Most MS-detecting cases belonged to the whole gain/loss type, whereas unfavorable cases who died of disease showed partial gain/loss, MYCN-amplified, or silent types. CONCLUSIONS: Genomewide genetic analysis is useful to predict the outcome of patients. Although the cases whose tumors showed whole gain/loss may respond well to contemporary therapy, sparing intensive surgery, current therapeutic strategy may be insufficient for the subgroups with partial gain/loss, MYCN-amplified, or silent type. Validation of these results would provide new tools to predict clinical outcome of children with NB.

Adolescent↗

PubMed2006

Prediction of individual response to platinum/paclitaxel combination using novel marker genes in ovarian cancers.

We attempted to identify potent marker genes using a new statistical analysis and developed a prediction system for individual response to platinum/paclitaxel combination chemotherapy in ovarian cancer patients based on the hypothesis that expression analysis of a set of the key drug sensitivity genes for platinum and paclitaxel could allow us to predict therapeutic response to the combination. From 10 human ovarian cancer cell lines, genes correlative in the expression levels with cytotoxicities of cisplatin (CDDP) and paclitaxel were chosen. We first selected five reliable prediction markers for the two drugs from 22 genes already known as sensitivity determinants and then identified another 8 novel genes through a two-dimensional mixed normal model using oligomicroarray expression data. Using expression data of genes quantified by real-time reverse transcription-PCR, we fixed the best linear model, which converted the quantified expression data into an IC(50) of each drug. Multiple regression analysis of the selected genes yielded three prediction formulae for in vitro activity of CDDP and paclitaxel. In the same way, using the same genes selected in vitro, we then attempted to develop prediction formulae for progression-free survival to the platinum/paclitaxel combination. We therefore constructed possible formulae using different sets of 13 selected marker genes (5 known and 8 novel genes): Utility confirmation analyses using another nine test samples seemed to show that the formulae using a set of 8 novel marker genes alone could accurately predict progression-free survival (r = 0.683; P = 0.042).

Antineoplastic Agents, Phytogenic↗

PubMed2006

Diagnostic and prognostic impact of beta-catenin alterations in pediatric liver tumors.

Hepatoblastoma (HBL), a major childhood malignant neoplasm, represents the most frequent malignant liver tumor in childhood. Recent reports have shown the CTNNB1 coding beta-catenin protein to be frequently mutated or deleted at hot-spot regions involving exon 3 in HBL. We investigated the genetic alterations of the CTNNB1 coding beta-catenin protein and expression of several genes downstream of Wnt signals in 4 benign and 17 malignant pediatric liver tumors (PLTs) consisting of 15 HBL, 1 hepatocellular carcinoma, and 1 hepatic immature sarcoma. Of 17 malignant PLTs, 10 (56%) revealed pathogenic alterations of the CTNNB1 gene, including 4 with missense mutations at codons 28, 32, 34 or 44, and 6 with interstitial deletions that partially or totally affected exon 3. All 6 deletions were in-frame deletions without a frame shift. The high frequency without any correlation to histological type indicates that the CTNNB1 gene alteration is a crucial event in the tumorigenesis of malignant PLTs. The immunohistochemical studies in 17 malignant PLTs demonstrated the nuclear/cytoplasmic accumulation of beta-catenin to be positive in all tumor specimens except for one hepatic sarcoma. A histological examination revealed all HBL cases involving tumors without detectable CTNNB1 gene alterations to show high expression of beta-catenin, thus indicating the accumulation of beta-catenin to be a common event in malignant PLTs, including HBL and hepatocellular carcinoma. Among the Wnt signal genes downstream of beta-catenin, E-cadherin is expressed in all malignant PLTs, while cyclin D1 expression was significantly detected in malignant PLTs with an advanced stage of disease. An immunohistological examination of nuclear accumulation of beta-catenin may thus be useful for diagnosing malignant PLTs. On the other hand, the expression of cyclin D1, a gene downstream of beta-catenin, might play a role in tumor progression.

Cadherins↗

PubMed2006

Chemosensitivity prediction in esophageal squamous cell carcinoma: novel marker genes and efficacy-prediction formulae using their expression data.

Esophageal cancer is a highly lethal disease and the optimal therapy remains unclear. Since adjuvant chemotherapy gives a better chance of survival, we attempted to develop a chemosensitivity prediction model to improve individual responses to therapy. Comprehensive gene expression analyses (cDNA and oligonucleotide microarrays) and MTT assay of 8 drugs in 20 KYSE squamous cell carcinoma cell lines were performed to distinguish candidate marker genes whose expression levels reproducibly correlated with cellular drug sensitivities. After confirmation with real-time RT-PCR, we performed multiple regression analyses to develop drug-sensitivity prediction formulae using the quantified expression data of selected marker genes. Using the same sets of genes, we also constructed prediction models for individual clinical responses to 5-FU-based chemotherapy using 18 cases. We selected 5 better marker genes, known as drug sensitivity determinants, identified 9 novel predictive genes for 4 of 8 anticancer drugs [5-FU, CDDP, DOX, and CPT-11 (SN-38)], and developed highly predictive formulae of in vitro sensitivities to the 4 drugs and clinical responses to 5-FU-based adjuvant chemotherapies in terms of overall and disease-free survivals. Our selected genes are likely to be effective drug-sensitivity markers and formulae using the 9 novel genes would provide advantages in prediction.

Antineoplastic Agents↗

PubMed2005

Telomerase expression in noncancerous bronchial epithelia is a possible marker of early development of lung cancer.

Centrally located lung cancers in smokers frequently associated with subsequent primary tumors. We evaluated the telomerase expression chronologically in noncancerous epithelia as a risk factor of susceptibility to lung cancer development. Telomerase protein expression was examined in situ by immunohistochemistry in 26 noncancerous bronchial epithelia adjacent to centrally located early-stage lung cancers in sequential 23 patients treated by photodynamic therapy or surgery among 206 patients who underwent autofluorescence bronchoscopy from 1997 to 2003. Among the 15 lesions in 12 patients treated by photodynamic therapy alone, 11 lesions achieved complete remission after photodynamic therapy, and none of their noncancerous bronchial epithelia was telomerase positive. On the contrary, in the remaining four lesions, either recurrence or secondary lung cancer developed adjacent to the successfully treated primary cancer within 26 months, and the telomerase protein expression in noncancerous epithelia was detected before the secondary cancer development (P < 0.001). The overall relationship of human telomerase reverse transcriptase positivity in noncancerous epithelia and subsequent lung cancer development, including patients treated by radiation or surgery, showed higher significance (P < 0.0001). Histologically "normal" bronchial epithelia in smokers may unphysiologically express telomerase as a field, and such epithelia are likely susceptible to develop lung cancer. We propose that ectopic expression of telomerase in bronchial epithelia may precede transformation in human lung cancer development and that detection of telomerase protein in noncancerous bronchial epithelia will become a useful marker detecting high-risk patients for lung cancer development.

Biomarkers, Tumor↗

PubMed2005

Hepatic regeneration promotes engraftment of intraportally transplanted islet cells.

BACKGROUND: With the current donor shortage, future success with islet transplantation is incumbent upon the ability to use single-donor islets. Manipulating the recipient graft environment may allow the use of fewer islets to achieve insulin independence. METHODS: Isolated pancreatic islets from a single donor were intraportally transplanted to streptozotocin-diabetic rats immediately after 70% partial hepatectomy (HxPIT1, n = 12). Plasma glucose concentrations were monitored for 30 days; intravenous glucose tolerance tests and serum insulin concentrations were obtained at the second and fourth weeks; morphologic studies were performed on insulin-immunostained sections of the liver. RESULTS: from HxPIT1 rats were compared to those from rats transplanted with single-donor islet grafts (PIT1, n = 10) and double-donor islet grafts (PIT2, n = 7). Results Hyperglycemia was ameliorated in HxPIT1 and PIT2 rats after transplantation but not in PIT1 rats. Glucose tolerance and insulin secretion in the HxPIT1 group were superior to the PIT1 group and equivalent to those in the PIT2 group. Morphologically, the sizes of the grafted islets and individual beta cells from HxPIT1 rats were larger than those from PIT1 rats. CONCLUSIONS: In streptozotocin-diabetic rats, islet transplantation performed in regenerating liver results in improved insulin secretion and serum glucose control, even in the face of a limited number of islets.

Animals↗

PubMed2005

Intracellular cytokine patterns of peripheral blood T cells as a useful indicator of activeness of Crohn's disease.

Recently, the alteration of peripheral T cells has become a focus of attention in research on Crohn's disease (CD). To examine the characteristics of peripheral T cells in CD patients, we analyzed the expression of a memory T cell marker (CD45RO(Bright)CD3+) and the cytokine production by peripheral helper and cytotoxic T cells in patients with CD. With the use of monensin to prevent the secretion of cytokines under stimulation, we measured the count of intracellular cytokine-positive cells for production of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, interleukin (IL)-2, IL-4, IL-6, IL-10, and granulocyte-macrophage colony stimulating factor (GM-CSF) in the peripheral T cell population using flow-cytometry. The counts of lymphocytes, T cells, and helper T cells in patients with CD were significantly lower than in normal volunteers. Although no difference in the counts of lymphocytes, total T cells, helper and cytotoxic T cells was observed, the counts of intracellular cytokine producing helper T cells in IFN-gamma, TNF-alpha or GM-CSF were significantly higher in active cases than in quiescent cases. These results suggest that stable CD patients are immunosuppressive, and activation of some kinds of T-cells, especially Th1-associated cytokine producing T-cells, correlate with disease progression. Th1-associated cytokine analysis of peripheral T cells may be one of the useful markers to evaluate the activeness of Crohn's disease.

Adult↗

PubMed2005

Attenuation of telomerase activity by hammerhead ribozymes targeting human telomerase RNA and telomerase reverse transcriptase in pancreatic carcinoma cells.

In cancer gene therapies, it is ideal to target tumor-specific genes. Since telomerase is activated in almost all cancer cells but not most somatic cells, it is considered as one of the favorite targets for cancer gene therapies. Ribozymes are catalytic RNA molecules with site-specific endoribonuclease activity. In the present study, we designed hammerhead ribozymes against human telomerase RNA (hTR) and human reverse transcriptase subunit (hTERT) to evaluate their effect on the attenuation of telomerase in the pancreas cancer cell line, PK-8. Hammerhead ribozyme targeting hTR depressed the level of telomerase activity in PK-8 cells. pRc-hTR vector with ribozyme targeting hTR and pRc-hTERT vector with ribozyme targeting hTERT mRNA were transfected into PK-8 cells and depressed telomerase activity and target RNA, but in pRc-hTR transfectant, hTERT mRNA expression was slightly upregulated and in pRc-hTERT transfectant hTR expression was also slightly upregulated. These findings indicate the co-regulation of hTR and hTERT mRNA expression in cancer cells. Extrachromosomal replicational vector, pCEP4, containing ribozyme targeting hTERT mRNA showed the most effective inhibition of telomerase activity, suggesting that the continuous effect of ribozyme is necessary to inhibit telomerase activity. Since the level of hTERT mRNA expression is less than that of hTR expression in cancer cells, ribozyme targeting hTERT mRNA might be a more useful therapeutic strategy for cancer gene therapy. Moreover, the co-regulation of hTR and hTERT mRNA expression in cancer cells to maintain the levels of telomerase activity suggested that the strategy of inhibiting hTERT mRNA and hTR simultaneously has a powerful potential as a gene therapy for targeting human telomerase.

Base Sequence↗

PubMed2004

Slow-down of age-dependent telomere shortening is executed in human skin keratinocytes by hormesis-like-effects of trace hydrogen peroxide or by anti-oxidative effects of pro-vitamin C in common concurrently with reduction of intracellular oxidative stress.

The cellular life-span of cultivated human skin epidermis keratinocytes NHEK-F was shown to be extended up to 150% of population doubling levels (PDLs) by repetitive addition with two autooxidation-resistant derivatives of ascorbic acid (Asc), Asc-2-O-phosphate (Asc2P), and Asc-2-O-alpha-glucoside (Asc2G), respectively, but to be not extended with Asc itself. In contrast, hydrogen peroxide (H(2)O(2)) as dilute as 20 microM which was non-cytotoxic to the keratinocytes, or at 60 microM being marginally cytotoxic achieved the cellular longevity, unexpectedly, up to 160 and 120% of PDLs, respectively, being regarded as a hormesis-like stimulatory effect. The lifespan-extended cells that were administered with Asc2P, Asc2G, or 20 microM H(2)O(2) were prevented from senescence-induced symptoms such as PDL-dependent enlargement of a cell size of 14.7 microm finally up to 17.4 microm upon Hayflick's limit-called loss of proliferation ability as estimated with a channelizer, and retained young cell morphological aspects such as thick and compact shape and intense attachment to the culture substratum even upon advanced PDLs, whereas other non-extended cells looked like thin or fibrous shape and large size upon lower PDLs. The PDL-dependent shortening of telomeric DNA of 11.5 kb finally down to 9.12-8.10 kb upon Hayflick's limit was observed in common for each additive-given cells, but was decelerated in the following order: 20 microM H(2)O(2) > Asc2P = Asc2G > 60 microM H(2)O(2) > Asc = no additive, being in accord with the order of cell longevity. Intracellular reactive oxygen species (ROS) was diminished by Asc2P, Asc2G or 20 microM H(2)O(2), but not significantly by Asc or 60 microM H(2)O(2) as estimated by fluorometry using the redox indicator dye CDCFH. There was no appreciable difference among NHEK keratinocytes that were administered with or without diverse additives in terms of telomerase activity per cell, which was 1.40 x 10(4)-4.48 x 10(4) times lower for the keratinocytes than for HeLa cells which were examined as the typical tumor cells. Thus longevity of the keratinocytes was suggested to be achieved by slowdown of age-dependent shortening of telomeric DNA rather than by telomerase; telomeres may suffer from less DNA lesions due to the continuous and thorough repression of intracellular ROS, which was realized either by pro-vitamin C such as Asc2P or Asc2G that exerted an antioxidant ability more persistent than Asc itself or by 20 microM H(2)O(2) which diminished intracellular ROS assumedly through a hormesis-like effect.

Ascorbic Acid↗

PubMed2004

Expression profiling and differential screening between hepatoblastomas and the corresponding normal livers: identification of high expression of the PLK1 oncogene as a poor-prognostic indicator of hepatoblastomas.

Hepatoblastoma is one of the most common malignant liver tumors in young children. Recent evidences have suggested that the abnormalities in Wnt signaling pathway, as seen in frequent mutation of the beta-catenin gene, may play a role in the genesis of hepatoblastoma. However, the precise mechanism to cause the tumor has been elusive. To identify novel hepatoblastoma-related genes for unveiling the molecular mechanism of the tumorigenesis, a large-scale cloning of cDNAs and differential screening of their expression between hepatoblastomas and the corresponding normal livers were performed. We constructed four full-length-enriched cDNA libraries using an oligo-capping method from the primary tissues which included two hepatoblastomas with high levels of alpha-fetoprotein (AFP), a hepatoblastoma without production of AFP, and a normal liver tissue corresponded to the tumor. Among the 10,431 cDNAs randomly picked up and successfully sequenced, 847 (8.1%) were the genes with unknown function. Of interest, the expression profile among the two subsets of hepatoblastoma and a normal liver was extremely different. A semiquantitative RT-PCR analysis showed that 86 out of 1188 genes tested were differentially expressed between hepatoblastomas and the corresponding normal livers, but that only 11 of those were expressed at high levels in the tumors. Notably, PLK1 oncogene was expressed at very high levels in hepatoblastomas as compared to the normal infant's livers. Quantitative real-time RT-PCR analysis for the PLK1 mRNA levels in 74 primary hepatoblastomas and 29 corresponding nontumorous livers indicated that the patients with hepatoblastoma with high expression of PLK1 represented significantly poorer outcome than those with its low expression (5-year survival rate: 55.9 vs 87.0%, respectively, p=0.042), suggesting that the level of PLK1 expression is a novel marker to predict the prognosis of hepatoblastoma. Thus, the differentially expressed genes we have identified may become a useful tool to develop new diagnostic as well as therapeutic strategies of hepatoblastoma.

Cell Cycle Proteins↗

PubMed2004

An evaluation of laparoscopic cholecystectomy after selective percutaneous transhepatic gallbladder drainage for acute cholecystitis.

BACKGROUND: The aim of this study was to evaluate the safety and usefulness of laparoscopic cholecystectomy after selective percutaneous transhepatic gallbladder drainage in patients with severe acute cholecystitis and patients with acute cholecystitis and severe comorbid disease. METHODS: According to whether percutaneous transhepatic gallbladder drainage was performed before surgery, 133 patients with acute cholecystitis were divided into a percutaneous transhepatic gallbladder drainage group (n=60) and non-percutaneous-transhepatic-gallbladder-drainage group (n=73). Background factors, safety, and postoperative course were retrospectively evaluated and compared between these two groups. RESULTS: Compared with the non-percutaneous-transhepatic-gallbladder-drainage group, the percutaneous transhepatic gallbladder drainage group was significantly older (p=0.0009), had a higher frequency of comorbid disease (p=0.0252), and a worse American Society of Anesthesiology classification (p=0.0021). In individual statistical tests, body temperature (p=0.0288), white blood cell count (p=0.0175), and C-reactive protein value (p=0.0022) were significantly elevated in the percutaneous transhepatic gallbladder drainage group; however, for frequency of comorbid disease, body temperature, and white blood cell count, significance was removed by correction for multiple testing of data. There was no significant difference in gender distribution, history of upper abdominal surgery, or body mass index between the two groups. The duration of surgery was marginally but significantly longer in the percutaneous transhepatic gallbladder drainage group (p=0.0414; in a single statistical test; however, that significance was removed by correction for the multiple testing of data). Between the two groups, there was no significant difference in blood loss at surgery, frequency of postoperative complications, rate of conversion to open laparotomy, interval until oral feeding was resumed, and length of postoperative hospital stay. CONCLUSIONS: These data suggest that satisfactory outcomes can be achieved with selective pre-operative gallbladder drainage in older and sicker patients with acute cholecystitis.

Acute Disease↗

PubMed2004

Differential gene expressions during immortalization of normal human fibroblasts and endothelial cells transfected with human telomerase reverse transcriptase gene.

It is widely accepted that telomerase, which compensates for telomere shortening, is finally activated in almost all kinds of human malignant neoplasms, and ectopic expression of telomerase may endow some kinds of human somatic cells with indefinite proliferation capacity, i.e., immortality. To clarify the intrinsic responses required in acquiring immortality, we investigated the chronological changes in the expression levels of the cell cycle and apoptosis-related genes by real-time RT-PCR in human normal fibroblasts and endothelial cells after hTERT transfection. We found that fibroblast MJ90 required intrinsic responses including reversible upregulation of cell-cycle promoting genes and down-regulation of apoptosis-inducing genes in early phase after transfection, whereas the endothelial cell HUE142-2 did not. In addition, the microarray analysis of the fibroblast strains revealed that the dysregulated genes during cellular immortalization were different from those reported in fibroblasts probably having acquired telomere maintenance mechanism concomitant with hTERT induction. These findings indicate that cell-type specific differential gene expression after telomerase activation may be important to acquire telomere-maintenance capacity and immortality in some non-cancerous human cells. Investigation of these molecules may elucidate the differences in the capacity of acquiring immortality in cancer and normal somatic cells in future.

Apoptosis↗

PubMed2003

Expression profiling of favorable and unfavorable neuroblastomas.

Neuroblastomas show remarkable biological heterogeneity, resulting in favorable or unfavorable outcomes. To survey the differences in gene expression profiles between favorable and unfavorable neuroblastomas, we analyzed ten favorable neuroblastoma samples from patients whose tumors consequently regressed or matured and ten unfavorable tumor samples from patients who consequently died of disease using the microarray technique. In each sample, total RNA was labeled with Cy3 or Cy5 in reverse-trancriptase reaction and hybridized with our original microarray prepared with a cDNA library of human fetal brain. Microarray analysis revealed that 43 genes, including MYCN, hTERT, NME1 and cell cycle regulatory protein-coding genes, were highly expressed in unfavorable neuroblastomas, while another 80 genes were detected as highly expressed in favorable tumors, including neuronal differentiating genes and apoptotic inducing genes. Among favorable neuroblastoma samples, highly expressing genes in regressing tumors were different from those in maturing tumors. Expression profiling data revealed the existence of up-regulated and down-regulated gene clusters in favorable and unfavorable tumors. This cluster analysis is a powerful procedure to distinguish unfavorable tumors from favorable tumors as well as regressing tumors from maturing tumors among favorable tumors. The information obtained from expression profiling would clarify the key genes for cell growth, regression or maturation of neuroblastoma cells, and these genes will become diagnostic and therapeutic targets in human neuroblastoma in the future.

Apoptosis↗

PubMed2003

Telomerase as tumor marker.

Telomerase, a critical enzyme responsible for continuous cell growth, is repressed in most somatic cells except proliferating progenitor cells and activated lymphocytes, and activated in approximately 85% of human cancer tissues. Telomerase activity is a useful cancer-cell detecting marker in some types of cancers in which almost all cases show telomerase activation. In other types in which telomerase becomes upregulated according to tumor progression, it is a useful prognostic indicator. Detection of human telomerase reverse transcriptase (hTERT) mRNA or protein in various clinical samples is also applicable. However, careful attention should be paid to the false negative results due to the instability of this enzyme or hTERT mRNA and the existence of polymerase chain reaction inhibitors as well as the false-positive results due to the contamination by normal cells with telomerase activity. If these pitfalls are avoided, in situ detection of hTERT mRNA or protein will facilitate the reliability of telomerase as a tumor marker.

Animals↗

PubMed2003

Differential gene expression profiles between neuroblastomas with high telomerase activity and low telomerase activity.

PURPOSE: Neuroblastoma shows remarkable heterogeneity, resulting in favorable or unfavorable outcomes. The authors previously reported that high levels of telomerase activity correlated with unfavorable tumors, and telomere shortening without telomerase activity correlated with tumor regression. To identify the genes responsible for the biological characteristics of neuroblastoma, the authors applied microarray techniques. METHODS: Mixtures of total RNAs extracted from 10 neuroblastoma tissues with high and 10 with low telomerase activity were labeled with Cy3 or Cy5 by reverse transcriptase reaction, respectively, and hybridized with our original microarrays prepared with a cDNA library of human fetal brain. RESULTS: Expression of 63 genes including MYCN, hTERT, HSPCA, and cell cycle-related proteins was found to be increased in neuroblastomas with high telomerase activity, whereas another 46 genes, including neural differentiating genes, were detected as highly expressed in tumors with low telomerase activity. CONCLUSIONS: The expression profiling data indicated clusters of upregulated and downregulated genes tumors with high or low telomerase activity. The genes involved in differentiation/growth arrest of tumor cells were closely related to low telomerase activity in neuroblastoma. The genes overexpressed in tumors with high telomerase activity, including cell-cycle-related genes and transcriptional factors, would be candidates for novel prognosis-predicting factors as well as new therapeutic targets in aggressive neuroblastomas.

DNA, Neoplasm↗