Intraoperative hypotension affects postoperative acute kidney injury depending on the invasiveness of abdominal surgery: A retrospective cohort study

Intraoperative hypotension (IOH) or highly invasive surgery adversely affects postoperative clinical outcomes. It is, however, unclear whether IOH affects postoperative acute kidney injury (AKI) depending on the invasiveness of abdominal surgery. We speculated that IOH in highly invasive abdominal surgery is a significant risk factor for postoperative AKI. We retrospectively reviewed the data of 448 patients who underwent abdominal surgery. Patients were divided into 3 groups: highly (such as pancreaticoduodenectomy and hepatectomy), moderately (open abdominal surgery), and minimally (laparoscopic surgery) invasive surgeries. The association between the time-weighted average (TWA) of mean arterial pressure (MAP) values (≤60 and ≤ 55 mm Hg) and AKI occurrences in each group was assessed. Postoperative AKI occurred after highly, moderately, and minimally invasive surgeries in 33 of 222 (14.9%), 14 of 110 (12.7%), and 12 of 116 (10.3%) cases, respectively (P = .526). The median [interquartile range] of TWA-MAP ≤ 60 mm Hg, as an IOH parameter, was 0.94 [0.33-2.08] mm Hg in highly, 0.54 [0.16-1.46] mm Hg in moderately, and 0.14 [0.03-0.57] mm Hg in minimally invasive surgeries (P < 0001). In addition, there was a significant association between TWA-MAP and AKI in highly invasive surgery, unlike in moderately and minimally invasive surgery, with adjusted odds ratios (95% confidence interval) for TWA-MAP ≤ 60 and ≤ 55 mm Hg associated with AKI of 1.23 [1.00-1.52] (P = .049) and 1.55 [1.02-2.36] (P = .041), respectively. Intraoperative MAP ≤ 60 mm Hg in highly invasive abdominal surgery is associated with postoperative AKI, compared to moderately and minimally invasive surgeries. Additionally, low MAP thresholds in highly invasive surgery increase postoperative AKI risk.

Associations between 24-h movement behaviors and self-rated health: a representative sample of school-aged children and adolescents in Okinawa, Japan

OBJECTIVES

This study aimed to determine the associations between adherence to 24-h movement behavior guidelines and self-rated health (SRH) among Japanese adolescents according to their age group.

STUDY DESIGN

This was a cross-sectional study.

METHODS

Probability proportional sampling data, which were collected from six regions of Okinawa Prefecture, Japan, considering the number of schools, included 2408 fifth-grade students (aged 10-11 years) in 31 elementary schools and 4360 eighth-grade students (aged 13-14 years) in 30 junior high schools. SRH, moderate-to-vigorous physical activity (MVPA), screen time (ST), sleep duration, and confounding factors (sex, weight status, family affluence, parental support, school satisfaction, and school demands) were self-reported.

RESULTS

The logistic regression models showed that adherence to ST and sleep recommendations in elementary school students was associated with a high prevalence of good health only, whereas adherence to only MVPA, only sleep, ST and sleep, MVPA and sleep, and all three recommendations were associated with a high prevalence of good health among junior high school students. All combinations that included achievement of the recommended sleep duration were associated with SRH.

CONCLUSIONS

Achieving 24-h movement behavior guidelines, particularly sleep recommendations, is associated with better perceived health in school-aged children, especially in adolescents.

Trends in current alcohol use among Japanese adolescents by sociodemographic groups

Background

Alcohol is the most commonly used substance among Japanese adolescents, although its use has been declining recently. However, little is known whether the declining trend in adolescent drinking can be found across all sociodemographic characteristics. This study explored time trends in alcohol use among Japanese adolescents by sociodemographic characteristics between 2008 and 2016.

Methods

A repeated cross-sectional study was conducted using data from three prefectural-wide surveys of public high schools in Okinawa Prefecture, Japan, in 2008, 2012, and 2016. The study participants comprised 7,807 students in grades 10 to 12 (15-18 years). Alcohol use was defined as drinking one or more alcoholic beverages on at least one day in the past month. Demographic characteristics included grade, sex, and region, and socioeconomic status (SES) was assessed by family structure, parental education, and school type. Time trends in alcohol use over time by each sociodemographic group were assessed by the Cochran-Armitage test for trend.

Results

The overall prevalence of adolescent alcohol use significantly reduced from 20.7% (95% CI 19.1-22.3%) in 2008 to 9.5% (95%CI 8.4-10.6%) in 2016. Similar reducing trends in adolescent alcohol use were found across all of the demographic characteristics as well as the SES groups (all P for trends &lt;0.001). During the survey periods, there were no sex differences in alcohol use prevalence, while alcohol use was more prevalent among old graders. Alcohol use was also more prevalent among low SES groups than high SES groups. However, family structure in 2016 did not show significant differences in alcohol use.

Conclusions

Alcohol use among Japanese adolescents has been declining over time and this downward trend was similar for all demographic and socioeconomic subgroups. Further adolescent drinking prevention efforts should be implemented across all population subgroups. Moreover. monitoring of adolescent alcohol use should be continued.

Key messages

This study found that adolescent alcohol use in Japan has been decreasing over time across all population subgroups. The finding is a desired outcome from the viewpoint of the public health impact.

Adherence to 24-hour movement guidelines among Japanese elementary and junior high school students

Background

For optimal health benefits, the Canadian 24-Hour Movement Guidelines for Children and Youth (aged 5-17 years) recommend an achievement of ≥ 60 minutes of moderate-to-vigorous physical activity (MVPA), &lt;2 h of recreational screen time (ST), and 9-11 h for 5-13 years or 8-10 h for 14-17 years of sleep time (SLT) each day. There is little evidence showing the proportion of the recommendation in Japan, so we need to investigate. The aim of this study thus was to reveal the compliance to the recommendation with a large sample of Japanese elementary and junior high school children.

Methods

This study included 2408 students enrolled in fifth grade (aged 10-11 years) in 31 elementary schools, and 4360 students enrolled in eighth grade (aged 13-14 years) in 30 junior high schools. Each behaviour was assessed by a self-reported questionnaire. To analyze the differences in adherence to the recommendation between the school-aged group, we conducted a chi-analysis.

Results

Overall, only 4% of participants complied with all three recommendations, and 20% of the students did not comply with any of the recommendations (χ2=1390.87;p&lt;.001). Compared with MVPA and ST, SLT had a trend to be likely to achieve the recommendation in each school-age group. Elementary school students had a higher percentage of non-adherence to all recommendations (39%) than junior high school students (10.3%). The adherence to the recommendation of the ST & SLT simultaneously had no differences in each age group (11.5% for elementary schoolers and 12.7% for junior high schoolers). However, adherence to the recommendation of MVPA only, ST only, and MVPA & ST were higher in elementary schoolers, and the adherence to the recommendation of SLT only and MVPA & SLT were higher in junior high schoolers.

Conclusions

The proportion of adherence to at least one of the three recommendations is better in junior high school students than elementary school students in Okinawa, Japan.

Key messages

Health behaviour required improvement may differ by age group. It is necessary for particularly elementary school children in Okinawa to take proper countermeasures to improve the movement behaviours.

Loss of Ftsj1 perturbs codon-specific translation efficiency in the brain and is associated with X-linked intellectual disability

FtsJ RNA 2'-O-methyltransferase 1 (FTSJ1) gene has been implicated in X-linked intellectual disability (XLID), but the molecular pathogenesis is unknown. We show that Ftsj1 is responsible for 2'-O-methylation of 11 species of cytosolic transfer RNAs (tRNAs) at the anticodon region, and these modifications are abolished in Ftsj1 knockout (KO) mice and XLID patient-derived cells. Loss of 2'-O-methylation in Ftsj1 KO mouse selectively reduced the steady-state level of tRNA^Phe in the brain, resulting in a slow decoding at Phe codons. Ribosome profiling showed that translation efficiency is significantly reduced in a subset of genes that need to be efficiently translated to support synaptic organization and functions. Ftsj1 KO mice display immature synaptic morphology and aberrant synaptic plasticity, which are associated with anxiety-like and memory deficits. The data illuminate a fundamental role of tRNA modification in the brain through regulation of translation efficiency and provide mechanistic insights into FTSJ1-related XLID.

Aspiration of massive free air from a large bore intravenous catheter sheath: A case report

We firstly experienced a rare case demonstrating that massive volume of free air was aspirated from a large bore intravenous catheter sheath of the pulmonary arterial catheter during placement. A 44-year-old male patient underwent the emergency induction of anesthesia for transplantation of liver donated by the brain death subject. After the induction, the central venous and pulmonary artery catheter placement was conducted. The aspiration of venous blood confirmed the intravascular insertion, but massive free air was aspirated when we advanced the sheath proximally. A perforation of subclavian vein and subsequent pneumothorax was strongly suspected. The emergency computed tomography revealed no sign of pneumothorax, pneumomediastinum nor extravasation. The operation was undergone with intensive monitoring and no further adverse complication was observed. The postoperative medical inquiry concluded that the massive free air was not aspirated from extravascular space, for example, thorax or mediastinum through the tip of the sheath, but from the proximal main port of the sheath. When the tip of sheath is occluded by the migration into small vessels, the large negative pressure through side port might easily aspirate the air through the 1-way valve of the main proximal port. Physicians should keep in mind of the structure of the catheter sheath.

Study of factors related to social and emotional skills in early childhood in Japan

Background

There are numerous reports that social and emotional skills in early childhood have profound influence on lifelong health. The aim of this research is to determine the relation between the lifestyle and the social and emotional skills among children in present day Japan.

Methods

The object of analysis was a total of 110 parents of kindergarten students (56 boys, 48 girls,6 gender unknown) from 3 kindergartens in central Okinawa Island. The survey was conducted in mid-December 2019. Regarding the content of the survey, parents were asked to answer on a five-point scale, based on their subjective opinion, how good is their child, as compared to other children, in each of the 9 sub-scales of the social and emotional skills proposed in the 2015 OECD report, namely “perseverance,” “self-control,” “passion for goals,” “sociability,” “respect,” “caring,” “self-esteem,” “optimism,” “confidence.” Additionally, other question items were set, mainly to ask about the child's own lifestyle.

Results

The results of multivariate logistic regression analysis are following. As for “achieving goals:” 3 items for perseverance - “there are few likes and dislikes about food (OR:2.67, 95％CI:1.03～6.94, p=.043),” “Time for playing games on smartphone is determined (OR:3.21, 95％CI:1.19～8.68, p=.021),” “Eat more fruits (OR:3.03, 95％CI:1.24～8.26, p=.016),” are statistically significant. [Other results are omitted in this abstract]

Conclusions

It became clear that the acquisition of social and emotional skills during early childhood generally involves regular lifestyle and “discipline” at home as a whole. Besides, it is important for parent and child to do various activities together, including those aiming to increase cognitive skills. This study is considered to be a powerful evidence for the development of future intervention programme, aimed at acquiring social and emotional skills in early childhood.

Key messages

In early childhood family and kindergarten have to cooperate to foster social and emotional skills, important for lifelong health. This study is considered to be a powerful evidence for the development of future intervention programme, aimed at acquiring social and emotional skills in early childhood.

Creation of immortalised epithelial cells from ovarian endometrioma

Background:

Epithelial cells of endometriotic tissues are difficult to propagate in vitro as experimental material is scarce owing to their limited life span. However, there is an increasing concern regarding their malignant transformation in ovaries. The present study sought to generate their stable culture system.

Methods and results:

Purified epithelial cells isolated from ovarian endometriomas using microscopic manipulation were successfully immortalised by combinatorial transfection of human cyclinD1, cdk4 and human telomerase reverse transcriptase (hTERT) genes, whereas the introduction of hTERT alone, or together with cdk4, was insufficient for immortalisation, leading to cellular senescence. We confirmed stable cytokeratin expression in the immortalised cells, proving their epithelial origin. These cells expressed progesterone receptor B and showed significant growth inhibition by various progestins. Oestrogen receptor (ER) expression was detected in these cells, albeit at low levels. Additional overexpression of ERα generated stable cells with oestrogen-dependent growth activation. Soft-agar colony formation assay and nude mice xenograft experiments demonstrated that these cells, even those with additional inactivation of p53, did not have transformed phenotypes.

Conclusion:

We for the first time generated immortalised epithelial cells from ovarian endometrioma that retained sex steroid responsiveness. These cells are invaluable tools not only for the consistent in vitro work but also for the study of molecular pathogenesis or carcinogenesis of endometriosis.

Chemical Structure of Native Oxide Grown on Hydrogenterminated Silicon Surfaces

Chemical bonding features and suboxide compositions in native oxide grown on chemically-cleaned hydrogen-terminated Si(100) surfaces stored in pure water have been studied by using surface sensitive infrared spectroscopy and x-ray photoelectron spectroscopy. The LO phonon peak for the native oxide is located at 1210cm−1, which is shifted to a significantly lower wavenumber side than the ultrathin thermal oxide peak at 1250cm−1. This is because an appreciable amount of SiHx bonds are incorporated in the native oxide/Si interface and such hydrogen termination in the network dramatically reduces strained bonds in the interface. Very weak Si2+ suboxide signal from the oxide grown in pure water is also explained by the incorporated SiHx bonds which interrupt the Si2+ suboxide formation in the interface.

Cleaning and Oxidation of Heavily Doped Si Surfaces

HF-treated Si surfaces and the oxidation kinetics in pure water or in clean room air have systematically been studied by x-ray photoelectron spectroscopy (XPS). The oxidation of heavily-doped n-type Si appears to proceed parallel to the surface, resulting in the layer-by-layer oxidation. The oxide growth rate in pure water for heavily-doped n-type Si is significantly higher than that of heavily-doped ptype Si. This is explained by the electron tunneling from the Si conduction band to adsorbed O2 molecules to form the O2 state. O2 ions easily decompose and induce a surface electric field, enhancing the oxidation rate. The growth rate of native oxide on heavily-doped n-type Si is less sensitive to the crystallographic orientations than the case of lightly doped Si where the steric hindrance against oxygen molecules significantly lowers the oxidation rate of the (110) and (111) surfaces. We suggest that the decomposed oxygen can penetrate into Si without steric hindrance. It is also found that the oxidation of heavily-doped n-type Si in pure water is effectively suppressed by adding a small amount (10 ∼ 3600 ppm) of HCI.

Layer-by-Layer Oxidation of Silicon

Growth kinetics of native oxide on HF-treated Si surfaces terminated with Si-H bonds has been studied by angle-resolved x-ray photoelectron spectroscopy. The oxide growth rate in pure water for an n+ Si(100) surface is significantly high compared to that of p+, and the n or p type Si oxidation rate is in between. This is explained by the formation of ions through electron transfer from Si to adsorbed O2 molecules and the resulting enhancement of the oxidation rate. The oxide growth on Si(100) is faster than (110) and (111) as interpreted in terms of the steric hindrance for molecular oxygen adsorption on the hydrogen terminated silicon 1×1 surface structures.

Intraperitoneal administration of telomerase-specific oncolytic adenovirus sensitizes ovarian cancer cells to cisplatin and affects survival in a xenograft model with peritoneal dissemination

Despite tremendous development in chemotherapy for ovarian cancer over the past few decades, the prognosis of advanced cases with massive peritoneal dissemination is still unsatisfactory, and novel treatment modalities that can combine with chemotherapy are urgently needed. We recently developed virotherapy for solid tumors using telomerase-specific replication-selective adenoviruses (Telomelysin: OBP-301), in which the human telomerase reverse transcriptase (hTERT) gene promoter has been inserted to direct tumor-specific E1 gene expression. In this study, we investigated the anti-tumor effects of OBP-301, combined with cisplatin (CDDP), on ovarian cancer cells. In vitro treatment of SKOV3 cells with OBP-301 at a multiplicity of infection (MOI) of 0.01–100 induced significant cell death in a dose-dependent manner, with moderate cytotoxicity at an MOI of 1–10 and maximal cytotoxicity at an MOI of 100. In contrast, OBP-301 treatment of normal human cells showed no significant cell death at an MOI of 1–10 and exhibited modest cytotoxicity at an MOI of 100. The effects of low-dose CDDP at 0.5–1 μM, which induced only 20% cell death, were significantly augmented by combination with OBP-301 at an MOI of 1–10, finally achieving 40% cell death. Such enhancement of CDDP sensitivity was also observed in CDDP-resistant ovarian cancer cells. The combinatorial effects were further tested using a xenograft mouse model of SKOV3 with peritoneal dissemination. After intraperitoneal administration of OBP-301, we confirmed that injected OBP-301 fused with the green fluorescent protein (GFP) gene (OBP-401) was preferentially localized to peritoneal disseminations, as determined by fluorescence imaging. Treatment of mice with CDDP at low dose (0.5 mg kg^–1) had modest effects, showing a 10% decrease in disseminations, whereas combination with intraperitoneal administration of OBP-301 at an MOI of 10 led to enhanced effects, achieving an approximately 80% decrease in disseminations. Kaplan–Meier analysis showed improved overall survival of mice treated with CDDP plus OBP-301 compared with CDDP alone. These findings support the therapeutic potential of intraperitoneal administration of OBP-301 to sensitize ovarian cancer cells to CDDP.

Analysis of outcome of Stage I-III endometrial cancer treated with systematic operation omitting paraaortic lymphadenectomy

PURPOSE

The aim of this study was to assess the outcomes of endometrial cancer patients treated with systematic surgery omitting paraarotic lymphadenectomy.

PATIENTS AND METHODS

We retrospectively analyzed a consecutive series of 84 endometrioid-type endometrial cancer patients at FIGO Stage I, II or III without grossly metastatic paraaortic lymphadenodes, who underwent surgery at our institute.

RESULTS

Sixty-five patients (77%) underwent primary surgery with pelvic lymphadenectomy while the remaining 19 patients underwent surgery without lymphadenectomy due to severe medical complications or age greater than 70 years. The patients with high risk for recurrence were treated mainly by adjuvant irradiation therapy of the whole pelvis. The median follow-up period was 44 months. The 5-year overall survival (OS) rate was 92%, 92% and 65% for FIGO Stage I, II and III, respectively. Recurrence was detected in eight of the 82 optimally operated patients (9.8%). Out of the eight recurrent patients, five patients had a recurrent tumor at extra-pelvic sites (chest or abdomen), two patients had a recurrent tumor only in a paraaortic lymph node, and one patient had a recurrent tumor only in the vagina. Thus, the recurrence rate was relatively low, with 2.4% relapse at the paraarotic lymph nodes, and 5-year OS rate appeared to be favorable. However, all the six recurrent patients who underwent adjuvant radiation therapy had distant recurrence.

CONCLUSIONS

These findings indicate that omission of paraarotic lymphadenectomy may be acceptable for endometrial cancer patients without gross metastasis at this site. However, the high rate of distant recurrence after whole pelvic irradiation strongly indicates an urgent need to develop potent systemic adjuvant therapy, potentially by chemotherapy or chemoradiation therapy.

Distinct telomere length regulation in premalignant cervical and endometrial lesions: implications for the roles of telomeres in uterine carcinogenesis

Mouse models show that progressive shortening of telomeres with ageing causes chromosomal instability, which can lead to the initiation of cancer. However, it is unclear what roles telomere shortening plays in human carcinogenesis. The present study has investigated the involvement of telomere dynamics in uterine carcinogenesis. Using telomere-FISH (telo-FISH) assays, telomere lengths in premalignant and malignant cervical and endometrial lesions were measured and compared with chromosomal arm loss or gain. Telo-FISH signals were visualized with Cy3-labelled telomere-specific probes and presented as telomere intensity (TI). Early-stage cervical intraepithelial neoplasias (CINs), especially CIN2, had significantly shorter telomeres than corresponding normal squamous epithelia (p = 0.019), together with increased rates of chromosomal arm loss/gain (p < 0.001). Cervical cancers had relatively short telomeres, but they also showed greater heterogeneity than other sampled tissues, including those with long telomeres. In contrast, there was no significant difference between the telomere length of normal endometrium and of endometrial hyperplasia and endometrial cancer. There was no significant difference in the rate of chromosomal arm loss/gain between normal endometrium and endometrial hyperplasia. These findings suggest that progressive shortening of telomeres occurs in CIN, in association with chromosomal instability, which may play critical roles in cervical carcinogenesis. In contrast, endometrial hyperplasias have relatively stable telomeres without widespread chromosome alteration, implying that endometrial carcinogenesis involves mechanisms distinct from those of cervical carcinogenesis, possibly including microsatellite instability.

Creation of tumorigenic human endometrial epithelial cells with intact chromosomes by introducing defined genetic elements

Several genetic mutations have been identified in human endometrial cancers, but the specific combinations of mutations required to form endometrial cancer cells remain unknown. In the present study, we established an in vitro model of endometrial carcinogenesis, in which defined genetic elements were introduced into endometrial epithelial cells to create transformed endometrial cells at different stages. Introduction of the human papillomavirus type 16 E6/E7 gene and the human telomerase reverse transcriptase (hTERT) gene into human primary endometrial epithelial cells was sufficient to generate immortalized cells. Introduction of hTERT in early passages stabilized telomeres and created immortalized cells with normal karyotype, whereas introduction of hTERT in later passages generated immortalized cells but with widespread chromosome abnormalities. However, neither of those two immortalized cell lines exhibited tumorigenic phenotypes. Tumorigenic endometrial epithelial cells with invasive capacity were created by introducing a mutant K-ras allele into immortalized cells, keeping their chromosomes intact. Inhibiting the PTEN gene and activating Akt pathways did not create tumorigenic phenotypes, although the latter conferred anchorage-independent growth capacity. These findings suggest that neoplastic transformation of human endometrial cells can occur in the absence of widespread chromosomal abnormality, and that the combination of Rb inactivation, telomerase activation and altered K-ras signaling is sufficient for in vitro neoplastic transformation. The present experimental model can help clarify the genetic requirements for endometrial carcinogenesis, and it is useful for testing and developing specific inhibitors of specific oncogenic pathways.

A novel treatment of human malignant gliomas in vitro and in vivo: FADD gene transfer under the control of the human telomerase reverse transcriptase gene promoter

Telomerase activity has a close relationship with malignancies in many cell types and it is tightly regulated at the transcriptional level of human telomerase reverse transcriptase (hTERT). Utilizing the hTERT promoter, the authors developed a gene delivery system of Fas associated protein with death domain (FADD) (hTERT/FADD). FADD is a protein which plays an important role in the apoptotic pathway of Fas. Over-expression of FADD induces apoptosis in the cells regardless of Fas expression on the cell surface. We hypothesized that we might be able to restrict the expression of FADD in malignant glioma cells if we use the gene transfer system under the control of hTERT promoter. This study was designed to investigate whether the hTERT/FADD construct induces apoptosis effectively in malignant glioma cells while keeping normal cells intact. First, using the reverse transcription-polymerase chain reaction (RT-PCR) technique, we confirmed that hTERT mRNA was expressed in human malignant glioma cells (U373-MG, A172 and GB-1), but not in cultured astrocytes (TEN) or fibroblasts (MRC5). After transient transfection with the hTERT/FADD construct, a significant number of FADD-positive cells and apoptotic cells were detected in hTERT-positive malignant glioma cells. In contrast, hTERT-negative astrocytes and fibroblasts remained intact. Furthermore, subcutaneously implanted U373-MG tumors treated with the hTERT/FADD construct reduced in volume significantly compared to the conrol treatment (p=0.0001). Gene transfer of FADD under the control of the hTERT promoter may be a novel and promising therapy to kill hTERT-positive malignant glioma cells while sparing normal brain cells lacking hTERT.

Covariation of cigarette smoking and other health-risk behaviors among Japanese high school students: a preliminary study

This study aims to determine if cigarette smoking is associated with engaging in other health-risk behaviors among high school students in Japan. Self-administered anonymous questionnaires were conducted in 1999 using a sample of 1,466 students (male: 50.5%, female: 49.5%) in grades 10 through 12 at seven public senior high schools in urban areas of Okinawa, Japan. Health-risk behaviors studiedal included cigarette smoking, alcohol drinking, thinner use, sexual intercourse, suicidal ideation, nonuse of seat belts, physical inactivity, and weight loss practices. In the logistic regression models, controlled for sociodemographic variables, smoking was significantly associated with all health-risk behaviors except physical inactivity. In particular, associations of alcohol drinking and sexual intercourse with smoking were strong. Among male students, statistically significant odds ratios existed for alcohol drinking, sexual intercourse, and nonuse of seat belts. Among female students, all of the odds ratios for health-risk behaviors were statistically significant, except for physical inactivity. Generally, the odds ratios of female students were higher than those of male students. In conclusion, high school students who smoked cigarettes in this study may be at higher risk for engaging in other health-risk behaviors. Particularly, alcohol drinking and sexual intercourse are more likely to co-occur with smoking. These findings suggest that smoking prevention programs should be integrated with other health-risk behaviors.

Treatment of malignant glioma cells with the transfer of constitutively active caspase-6 using the human telomerase catalytic subunit (human telomerase reverse transcriptase) gene promoter

Because the apoptotic pathway is often disrupted in tumor cells, its genetic restoration is a very attractive approach for the treatment of tumors. To treat malignant gliomas with this approach, it would be preferred to restrict induction of apoptosis to tumor cells by establishing a tumor-specific expression system. Telomerase is an attractive target because the vast majority of malignant gliomas have telomerase activity whereas normal brain cells do not. Activation of telomerase is tightly regulated at the transcriptional level of the telomerase catalytic subunit [human telomerase reverse transcriptase, (hTERT)]. Therefore, we hypothesized that using a hTERT promoter-driven vector system, an apoptosis-inducible gene may be preferentially restricted to telomerase- or hTERT-positive tumor cells. In this study, we constructed an expression vector consisting of the constitutively active caspase-6 (rev-caspase-6) under the hTERT promoter (hTERT/rev-caspase-6) and then investigated its antitumor effect on malignant glioma cells. The rationale for using the rev-caspase-6 gene is because it induces apoptosis independent of the initiator caspases. We demonstrated that the hTERT/rev-caspase-6 construct induced apoptosis in hTERT-positive malignant glioma cells, but not in hTERT-negative astrocytes, fibroblasts, and alternative lengthening of telomeres cells. In addition, the growth of s.c. tumors in nude mice was significantly suppressed by the treatment with hTERT/rev-caspase-6 construct. The present results strongly suggest that the telomerase-specific transfer of the rev-caspase-6 gene under the hTERT promoter is a novel targeting approach for the treatment of malignant gliomas.

Telomerase activation by histone deacetylase inhibitor in normal cells

Although telomerase activity is known to be regulated mainly at the level of transcription of the human telomerase catalytic subunit (hTERT) gene, the molecular mechanism underlying tumor-specific expression of telomerase remains unclear. Emerging evidence suggests that reversible acetylation of nucleosomal histones and the resultant changes in the chromatin structure are important processes in gene transcription. In particular, histone deacetylase (HDAC) inhibitors activate the transcription of certain genes by altering the acetylation status of nucleosomal histones. The present study examines the effects of HDAC inhibitor on hTERT gene transcription. Treatment with tricostatin A (TSA) induced significant activation of hTERT mRNA expression and telomerase activity in normal cells, but not in cancer cells. Transient expression assays revealed that TSA activates the hTERT promoter. Furthermore, the proximal 181 bp core promoter of hTERT, which contains two c-Myc and five Sp1 sites, was determined to be the responsible element. Overexpression of Sp1 enhanced responsiveness to TSA, and mutation of Sp1 sites, but not c-Myc sites, of the core promoter of hTERT abrogated this activation. Introduction of the dominant-negative form of the Sp family inhibited TSA activation. These results indicate that HDAC inhibitor activates the hTERT promoter in normal cells, in which Sp1 plays a key role. This finding suggests one way whereby histone deacetylation may be involved in silencing the hTERT gene in normal cells.

The relationship between anthropometric indicators of nutritional status and malaria infection among youths in Khammouane Province, Lao PDR

We assessed anthropometric indicators of the nutritional status among children and adolescents in Khammouane Province in the Lao PDR and examined the relation between malnutrition and malaria infection. The survey was conducted from July to August 1999 using a sample of 309 youths aged 2 to 18 years. Malnutrition was categorized as stunting (below -2 Z scores height-for-age) and wasting (below -2 Z scores weight-for-height). The prevalence of stunting and wasting were 45.1% and 9.2%, respectively, which were classified by WHO as "very high" prevalence. Compared with the results of previous national surveys in Lao PDR, similar prevalence was shown. The prevalence of wasting in youths with P. falciparum infection was 17%, significantly higher than those of not infected (4%). On the other hand, P. vivax infection was not associated with any indicators of malnutrition. In conclusion, this study showed that the nutritional status in youths was poor and P. falciparum infection was associated with acute malnutrition.

FADD gene therapy using the human telomerase catalytic subunit (hTERT) gene promoter to restrict induction of apoptosis to tumors in vitro and in vivo

Gene transfer vectors will dramatically increase the safety and effectiveness of cancer gene therapy, if they could restrict expression of the therapeutic products to the target tumors. To realize such a tumor-targeting system, telomerase is one of the most promising candidates. It is because telomerase activity is detected in the vast majority of tumors, but not in most normal cells. Activation of telomerase is tightly regulated at the transcriptional level of the telomerase catalytic subunit (hTERT). Therefore, the use of the hTERT promoter-driven vector system could restrict the expression of therapeutic products to telomerase-positive tumors. In this study, we constructed the expression vector of FADD gene with death domain afforded by the hTERT promoter (hTERT/FADD) and investigated its effect on tumors in vitro and in vivo. Transient transfection with the hTERT/FADD construct induced apoptosis in telomerase-positive tumor cells of wide range. In contrast, normal fibroblast cells without telomerase did not undergo apoptosis following the hTERT/FADD transfer. Furthermore, the growth of subcutaneous tumors in nude mice was significantly suppressed by the intratumoral injection of the hTERT/FADD construct (every day for one week) compared to the control (P<0.0005). The findings described here indicate the high potentiality of a novel telomerase-specific gene therapy of tumors with telomerase.

Psychosocial correlates of depressive symptoms among Japanese high school students

PURPOSE

To determine the psychosocial factors associated with the presence and persistence of depressive symptoms among high school students in Okinawa, Japan.

METHODS

The study sample was 3202 students from 12 public senior high schools. Students completed self-administered questionnaires from October through December 1997. We measured depressive symptomatology using the Center for Epidemiologic Studies Depression Scale. We asked students to report whether they had depressive symptoms at any time in the immediate past week, and whether those symptoms persisted for 5-7 days. The psychosocial variables examined were life stressors, perceived social support, health practices, self-esteem, and Locus of Control. The relationship between the psychosocial factors and depressive symptoms was examined using hierarchical multiple regression analyses.

RESULTS

After controlling for the effects of demographic and other psychosocial variables, presence of depressive symptoms was positively associated with life stressors in the domains of friends, family, and teachers. Similarly, persistence of depressive symptoms was also positively associated with life stressors in the domains of friends and teachers. Presence and persistence of depressive symptoms were negatively associated with positive health practices, more social support, high self-esteem, and internal Locus of Control.

CONCLUSIONS

The psychosocial variables associated with presence and persistence of depressive symptoms were remarkably consistent. Life stressors might be risk factors; on the contrary, positive health practices, perceived social support, high self-esteem, and internal Locus of Control might be protective factors of depressive symptoms among Japanese adolescents.

Patterns of health-risk behavior among Japanese high school students

This study explored patterns of health-risk behaviors among Japanese high school students and examined if a cluster and an accumulation of health-risk behaviors existed. Self-administered questionnaires were employed in 1999 using a sample of 1,466 students (male 50.5%, female 49.5%) in grades 10 through 12 at seven public senior high schools in Okinawa, Japan. Health-risk behaviors studied included cigarette smoking, alcohol use, thinner use, nonuse of seat belts, suicide ideation, sexual intercourse, weight loss practices, and physical inactivity. Among male and female students, cigarette smoking, alcohol use, and sexual intercourse clustered. Accumulation of these risk behaviors also occurred because the observed proportion was greater than the expected proportion assuming independent occurrence. Vocational high school students and upper graders were strongly associated with accumulation of health risk behaviors. These findings identify a high-risk target group among Japanese adolescents and suggest that preventive intervention strategies should take into consideration the cluster and accumulation of health-risk behaviors.

Gender differences in the association between psychosocial factors and depressive symptoms in Japanese junior high school students

To determine psychosocial factors associated both with depressive symptoms and with gender differences in depressive symptoms among junior high school students, we conducted self-administered questionnaires using a sample of 2,660 students of 13 public junior high schools in Okinawa, Japan. Depressive symptomatology was measured by the Center for Epidemiologic Studies Depression Scale (CES-D). The psychosocial variables examined were life stresses, social support, health practices, self-esteem, and locus of control. Depressive symptoms were positively associated with life stresses and negatively associated with health practices, social support, self-esteem, and internal locus of control. In addition, female students were likely to report more depressive symptoms, life stresses, and low self-esteem and poor health practices. After controlling for the psychosocial variables differed by gender, gender differences in depressive symptoms were eliminated. In conclusion, for depressive symptoms of junior high school students, life stresses might be risk factors, but positive health practices, social support, high self-esteem, and internal locus of control might be protective factors. Gender differences in depressive symptoms could be explained by the females' elevation on these psychosocial variables.

Progesterone regulates human telomerase reverse transcriptase gene expression via activation of mitogen-activated protein kinase signaling pathway

Emerging evidence indicates that sex steroid hormones regulate telomerase in target tissues. We have reported that estrogen activates telomerase through transactivation of the telomerase catalytic subunit, human telomerase reverse transcriptase (hTERT). Progesterone usually antagonizes estrogen action in reproductive organs, but the effect on telomerase remains unclear. In this study, we examine the effects of progesterone on the gene expression of hTERT in breast and endometrial cancer cell lines expressing progesterone receptor. Progesterone significantly induced hTERT mRNA expression within 3 h after exposure. This transient effect peaked at 12 h and then decreased. In contrast, exposure to progesterone for > 48 h antagonized estrogen effects and inhibited the estrogen-induced activation of hTERT expression; the cyclin-dependent kinase inhibitor p21/Waf1/Cip1 plays an integral role in this inhibition. Thus, progesterone exerts diverse effects on hTERT mRNA expression in a time-dependent manner. We also found that the mitogen-activated protein kinase signaling pathway mediates both the short-term and long-term effects of progesterone on hTERT gene expression. These findings support the notion that hTERT gene is a target of both estrogen and progesterone.

Tumor-specific transgene expression from the human telomerase reverse transcriptase promoter enables targeting of the therapeutic effects of the Bax gene to cancers

Human telomerase reverse transcriptase (hTERT) is the catalytic subunit of telomerase, which is highly active in immortalized cells and >85% of human cancers but is quiescent in most normal somatic cells. To test the feasibility of using the hTERT promoter to induce tumor-specific transgene expression in cancer gene therapy, we constructed an adenoviral vector expressing a LacZ reporter gene driven by the hTERT core promoter and evaluated its activity in vitro and in vivo. The hTERT promoter could drive high-level expression of LacZ in tumor cells but not in normal cells and normal mouse tissues. Using a binary adenoviral system that can induce Bax gene expression, we showed that induction of the Bax gene expression via the hTERT promoter elicited tumor-specific apoptosis in vitro, suppressed tumor growth in nude mice, and prevented the toxicity of the Bax gene in vitro and in vivo. Thus, the hTERT promoter is apparently a strong and tumor-selective promoter with potential application in targeted cancer gene therapy.

A case of cervical cancer with aggressive tumor growth: possible autocrine growth stimulation by G-CSF and Il-6

BACKGROUND

Patients with tumors that produce hematopoietic growth factors, such as G-CSF, sometimes exhibit leukemoid reactions. Squamous cell carcinomas of the uterine cervix producing such factors are rarely reported.

CASE

A 56-year-old woman had severe leukocytosis (>50 x 10(3)/microl) and fever without evidence of infection after radical hysterectomy for treatment of her cervical cancer. The parametrial recurrent mass appeared after the operation and exhibited extremely aggressive growth. Serum levels of G-CSF and IL-6 were extremely high, and immunohistochemical analysis and RT-PCR assays revealed that G-CSF and IL-6 as well as their receptors were produced in tumor cells.

CONCLUSIONS

This is a case of cervical cancer which exhibited an aggressive clinical course, possibly due to autocrine stimulation of cell growth by G-CSF and IL-6.

A novel telomerase-specific gene therapy: gene transfer of caspase-8 utilizing the human telomerase catalytic subunit gene promoter

Apoptosis is a genetically encoded cell death process and is a pathway that may be disrupted in tumor cells. Therefore, therapies that restore the ability to undergo apoptosis are promising for the treatment of tumor cells. We have demonstrated that the transfer of apoptosis-inducible genes inhibits the growth of tumors in vitro and in vivo through induction of apoptosis. However, to restrict induction of apoptosis to tumor cells, we need to explore a tumor-specific expression system of these genes. In the present study, we developed the telomerase-specific transfer system of apoptosis-inducible genes, utilizing the promoter of the human telomerase catalytic subunit (hTERT) gene. Approximately 90% of tumors have telomerase activity whereas most normal cells do not express the activity. These observations indicate that telomerase is a particularly attractive target for the tumor-specific expression system of vectors. We demonstrate here that by using the hTERT promoter-driven caspase-8 expression vector (hTERT/caspase-8), apoptosis is restricted to telomerase-positive tumor cells of wide range, and is not seen in normal fibroblast cells without telomerase activity. Furthermore, treatment of subcutaneous tumors in nude mice with the hTERT/caspase-8 construct inhibited tumor growth significantly because of induction of apoptosis (p < 0.01). The telomerase-specific expression of apoptosis-inducible genes afforded by the hTERT promoter, therefore, may be a novel and promising targeting approach for the treatment of tumors with telomerase activity.

Demethylating reagent 5-azacytidine inhibits telomerase activity in human prostate cancer cells through transcriptional repression of hTERT

Telomerase activation is thought to be a critical step in cellular immortality and oncogenesis. Several reagents including differentiation-inducing and antineoplastic agents are known to inhibit telomerase activity, although the molecular mechanisms through which they inhibit telomerase activity remain unclear. Demethylating reagents have recently been used as potential antineoplastic drugs for some types of cancers including those of the prostate. In the present study, we examined the effect of the demethylating reagent 5-azacytidine (5-aza-CR) on telomerase activity using cells of two prostate cancer cell lines, DU-145 and TSU-PR1. 5-aza-CR treatment significantly reduced telomerase activity in TSU-PR1 cells, but not in DU-145 cells, although growth inhibition was observed to a similar extent in both cell lines. Reverse transcription-PCR analyses revealed that inhibition of telomerase activity was accompanied by down-regulation of telomerase catalytic subunit (hTERT) mRNA expression. Transient expression assays showed that 5-aza-CR repressed the transcriptional activity of the hTERT promoter and that the E-box within the core promoter was responsible for this down-regulation. Western blot analyses revealed that 5-aza-CR reactivated p16 expression and repressed c-Myc expression in TSU-PR1 cells but not in DU-145 cells. Overexpression of p16 in TSU-PR1 cells led to significant repression of c-Myc transcription. These findings suggest that 5-aza-CR inhibits telomerase activity via transcriptional repression of hTERT, in which p16 and c-Myc may play a key role.

Identification and characterization of negative regulatory elements of the human telomerase catalytic subunit (hTERT) gene promoter: possible role of MZF-2 in transcriptional repression of hTERT

Human telomerase reverse transcriptase (hTERT) is a catalytic subunit of human telomerase and is a critical determinant of the enzymatic activity of telomerase. Expression of hTERT is known to be regulated mainly at the transcriptional level. In the present study, using transient expression assays, we identified a 400 bp silencer of the hTERT promoter between -776 and -378 upstream of the proximal core promoter. The inhibitory effects of this silencer were enhanced with cellular differentiation. A computer-assisted homology search identified multiple binding motifs for myeloid-specific zinc finger protein 2 (MZF-2) within this region. Mutation introduced in these sites resulted in significant activation of hTERT transcription. Gel shift assays demonstrated that MZF-2 proteins specifically bound to these sites. Overexpression of MZF-2 in cells led to down-regulation of hTERT transcription as well as telomerase activity. These findings suggest that the 400 bp region upstream of the hTERT core promoter that we identified functions as a negative regulatory region and that MZF-2 may be an effector of negative regulation of hTERT.

Telomerase activity in cancer as a diagnostic and therapeutic target

Major advances have been made in understanding the role of telomerase in cellular immortalization and carcinogenesis. Human telomeres undergo progressive shortening with cell division, and critical shortening of telomeres with cellular aging triggers a signal for cells to stop dividing and senesce. Telomerase is an enzyme that adds telomeric-repeated sequences to the ends of human chromosome DNA. Telomerase is active in the vast majority of tumors, but not in normal somatic tissues, and prevents progressive shortening of telomeres with cell division, probably giving tumor cells a growth advantage over normal cells. Highly-sensitive PCR-based TRAP (telomeric repeat amplification protocol) assay provided the means to analyze telomerase in a wide variety of tissues. Evidence has been accumulated that this assay may be useful as a potential diagnostic tool for cancer. The constituents of telomerase complex have recently been identified, and human telomerase reverse transcriptase (hTERT) has been found to be responsible for the enzymatic activity of telomerase. Detection of hTERT mRNA may therefore be useful for the screening and diagnosis of cancers. The mechanisms regulating hTERT expression have been extensively analyzed, and transcriptional regulation of hTERT has been found to be essential for hTERT expression, in which several nuclear factors including c-Myc play crucial roles. Understanding of such mechanisms might provide insight into molecular basis of human carcinogenesis and contributes to the development of novel cancer gene therapy targeting telomerase.

Risk factors for cigarette smoking among high school students in Okinawa, Japan

The purpose of this study was to examine the relationships between risk factors and smoking status among high school students in Okinawa, Japan. We also examined if there is a dose-response relation between the number of risk factors and smoking status. Self-reported questionnaires including smoking status and potential risk factors were conducted using a sample of 1,029 students of a public senior high school in Okinawa. The percentage of smokers was 40.0% for males and 10.6% for females, and it was significantly higher for males than females. As a result of multivariate analysis, we identified four significant risk factors; peer smoking, attitude of peer toward subject smoking, intention to smoke at the age 20, and alcohol drinking. The number of these risk factors was linearly associated with increased percentage of smokers, and a linear trend was significant for both gender students. Additionally, magnitude of risk for smoking among females became considerably great compared with those of males as the number of risk factors increased. In conclusion, this study was the first study in Japan to indicate a significant dose-response relationship between the number of risk factors and smoking status among high school students. We also found that females with many risk factors had extremely increased vulnerability to smoking compared to male counterpart. These findings may be useful to identify high-risk students who need more intensive smoking prevention programs and to develop the content of effective interventions.

Adenoviral expression of p53 represses telomerase activity through down-regulation of human telomerase reverse transcriptase transcription

Telomerase activation is a critical step in cellular immortality and oncogenesis. The activity of telomerase is known to be correlated with cell proliferation, but its regulation by cell cycle regulators is not well understood. In the present study, we examined the effects of p53 on telomerase activity. Wild-type p53 was introduced into SiHa cells via a recombinant adenoviral vector, Ad5CMV-p53, and change in telomerase activity was examined by quantitative telomerase assay. Telomerase activity in the Ad5CMV-p53-infected cells was significantly repressed 36 h after infection following down-regulation of human telomerase catalytic subunit [human telomerase reverse transcriptase (hTERT)] mRNA expression, whereas no change in telomerase activity was observed in the cells infected with control vector AdSCMV-beta-gal. Interestingly, repression of telomerase activity was an early event that preceded cell growth inhibition or apoptosis induced by p53 overexpression, suggesting that p53 directly regulates telomerase activity. Transient expression assays using hTERT-promoter reporter constructs revealed that overexpression of p53 significantly repressed promoter activity of hTERT. 5'-Truncation of the promoter sequences revealed that the proximal core promoter region containing multiple binding sites for transcription factor Spl was responsible for p53-mediated transcriptional repression. Mutations in these binding sites for Spl led to failure of p53 to repress transcription. These findings suggest that p53 repressed telomerase activity through down-regulation of hTERT transcription and that interaction of p53 with Sp1 or other transcription factors may be involved in this regulation.

Sp1 cooperates with c-Myc to activate transcription of the human telomerase reverse transcriptase gene (hTERT)

Telomerase activation is thought to be a critical step in cellular immortalization and carcinogenesis. The human telomerase catalytic subunit (hTERT) is a rate limiting determinant of the enzymatic activity of human telomerase. In the previous study, we identified the proximal 181 bp core promoter responsible for transcriptional activity of the hTERT gene. To identify the regulatory factors of transcription, transient expression assays were performed using hTERT promoter reporter plasmids. Serial deletion assays of the core promoter revealed that the 5'-region containing the E-box, which binds Myc/Max, as well as the 3'-region containing the GC-box, which binds Sp1, are essential for transactivation. The mutations introduced in the E-box or GC-box significantly decreased transcriptional activity of the promoter. Overexpression of Myc/Max or Sp1 led to significant activation of transcription in a cell type-specific manner, while Mad/Max introduction repressed it. However, the effects of Myc/Max on transactivation were marginal when Sp1 sites were mutated. Western blot analysis using various cell lines revealed a positive correlation between c-Myc and Sp1 expression and transcriptional activity of hTERT. Using fibroblast lineages in different stages of transformation, we found that c-Myc and Sp1 were induced to a dramatic extent when cells overcame replicative senescence and obtained immortal characteristics, in association with telomerase activation. These findings suggest that c-Myc and Sp1 cooperatively function as the major determinants of hTERT expression, and that the switching functions of Myc/Max and Mad/Max might also play roles in telomerase regulation.

Estrogen activates telomerase

Telomerase activity is present in most malignant tumors and provides a mechanism for the unlimited potential for division of neoplastic cells. Although telomerase is known to be a regulated enzyme, the factors and mechanisms involved in telomerase regulation are not well understood. In the present study, we examined the effects of estrogen on telomerase activity. Telomerase activity in estrogen receptor (ER)-positive MCF-7 cells was up-regulated by the treatment with 17beta-estradiol. This activation accompanied up-regulation of the telomerase catalytic subunit, hTERT mRNA. Gel shift assays revealed that the imperfect palindromic estrogen-responsive element in the hTERT promoter specifically binds to ER. Transient expression assays using luciferase reporter plasmids containing various fragments of hTERT promoter showed that this imperfect palindromic estrogen-responsive element is responsible for transcriptional activation by ligand-activated ER. We also found that estrogen activates c-Myc expression in MCF-7 cells and that E-boxes in the hTERT promoter that bind c-Myc/Max play additional roles in estrogen-induced transactivation of hTERT. Estrogen thus activates telomerase via direct and indirect effects on the hTERT promoter. These findings may help elucidate the mechanisms of hormonal control of telomerase activity and aid understanding of the roles of sex steroids in cellular senescence and aging as well as estrogen-induced carcinogenesis.

Morphologic analysis of dentofacial structure in patients with acromegaly

The purpose of this study was to investigate the morphologic changes of the oral and maxillofacial skeletal structure in patients with acromegaly and the correlation between growth hormone, age at onset, and duration. Fifty-four acromegalic patients (28 men and 26 women) were compared with 45 normal adults (23 men and 22 women) using casts and cephalometric analysis. The incisor relationship was classified into four types: edge-to-edge bite, crossbite, maxillary incisor protrusion, and normal bite. Many cases of edge-to-edge bite and crossbite were observed in acromegalic patients. The most characteristic craniofacial skeletal differences in patients with acromegaly were protruded glabella and increased anterior face height. Enlargement of the ascending ramus and prominence of the mandible, chin, and mouth were the most noticeable profile characteristics of acromegalic patients. Male patients tended to demonstrate downward mandibular advancement and crossbite, while females showed extension of the ascending ramus, downward displacement of mandible, bimaxillary alveolar protrusion, and edge-to-edge bite.

Expression of human telomerase subunits in ovarian malignant, borderline and benign tumors

Telomerase activity is involved in the maintenance of telomere length and is thought to be required for cellular immortality and oncogenesis. Three major subunits composing telomerase, human telomerase RNA (hTR), telomerase-associated protein (TPI) and human telomerase catalytic subunit (hTERT), have been identified. However, their functions and the regulatory mechanisms by which telomerase is activated have not been fully determined. In the present study, a total of 35 epithelial ovarian cancers, 5 ovarian low potential malignancies (LPM), 11 ovarian benign cysts and 12 normal ovaries, as well as various cell lines derived from ovarian cancers, were examined for the expression of hTR, TPI mRNA and hTERT mRNA. Correlations of expression with telomerase activity were evaluated. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that hTR and TPI mRNA were expressed in more than 80% of ovarian cancers, LPM, ovarian cysts and even in normal ovaries. However, hTERT mRNA was observed only in ovarian cancers, most of which exhibited telomerase activity. Normal ovarian tissues, ovarian cysts and LPM, most of which had no telomerase activity, did not express hTERT. Five telomerase-positive ovarian cancer cell lines expressed each of the telomerase subunits, whereas 2 telomerase-negative normal primary fibroblast cell lines expressed TPI mRNA and hTR, but not hTERT mRNA. There was a significant correlation of telomerase activity with hTERT mRNA expression but not with TPI or hTR expression. Expression of hTERT is thus specific to cancer lesions and appears to be a rate-limiting determinant of the enzymatic activity of human telomerase. Up-regulation of hTERT may play a critically important role in the development of ovarian cancers.

Expression of human telomerase subunits in ovarian malignant, borderline and benign tumors

Telomerase activity is involved in the maintenance of telomere length and is thought to be required for cellular immortality and oncogenesis. Three major subunits composing telomerase, human telomerase RNA (hTR), telomerase-associated protein (TPI) and human telomerase catalytic subunit (hTERT), have been identified. However, their functions and the regulatory mechanisms by which telomerase is activated have not been fully determined. In the present study, a total of 35 epithelial ovarian cancers, 5 ovarian low potential malignancies (LPM), 11 ovarian benign cysts and 12 normal ovaries, as well as various cell lines derived from ovarian cancers, were examined for the expression of hTR, TPI mRNA and hTERT mRNA. Correlations of expression with telomerase activity were evaluated. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that hTR and TPI mRNA were expressed in more than 80% of ovarian cancers, LPM, ovarian cysts and even in normal ovaries. However, hTERT mRNA was observed only in ovarian cancers, most of which exhibited telomerase activity. Normal ovarian tissues, ovarian cysts and LPM, most of which had no telomerase activity, did not express hTERT. Five telomerase-positive ovarian cancer cell lines expressed each of the telomerase subunits, whereas 2 telomerase-negative normal primary fibroblast cell lines expressed TPI mRNA and hTR, but not hTERT mRNA. There was a significant correlation of telomerase activity with hTERT mRNA expression but not with TPI or hTR expression. Expression of hTERT is thus specific to cancer lesions and appears to be a rate-limiting determinant of the enzymatic activity of human telomerase. Up-regulation of hTERT may play a critically important role in the development of ovarian cancers.

Human telomerase reverse transcriptase as a critical determinant of telomerase activity in normal and malignant endometrial tissues

Telomerase activation is thought to be essential for cellular immortality and oncogenesis. It is observed in most malignant tumors but not in most normal somatic tissues. Normal human endometrium is, however, known to express significant telomerase activity in a menstrual phase-dependent manner. The 3 major subunits composing telomerase have been identified. Using normal and malignant endometrial tissues, we studied how these components are involved in telomerase activation. A total of 23 endometrial cancers and 32 normal human endometria in various menstrual phases as well as cell lines derived from endometrial cancer were examined for the expression of each telomerase subunit using RT-PCR analysis. Telomerase activity in each sample was determined by the TRAP assay, and the correlation between subunit expression and telomerase activity was examined. RT-PCR analysis revealed that telomerase RNA (hTR) and telomerase-associated protein (TP1) mRNA were constitutively expressed in both normal and malignant endometrial tissues. Expression of human telomerase reverse transcriptase (hTERT) mRNA was observed in most endometrial cancers, while that in normal endometrium depended on the phases of menstrual cycles. Proliferative phase normal endometria expressed hTERT mRNA, while secretory phase endometria did not. There was a strong association between telomerase activity and hTERT expression but not TP1 or hTR expression in both normal and tumor tissues. Five telomerase-positive endometrial cancer cell lines expressed each of the telomerase subunits including hTERT, while 2 telomerase-negative normal primary fibroblast cells expressed TP1 mRNA and hTR, but not hTERT mRNA. Our findings suggest that hTERT is a rate-limiting determinant of enzymatic activity of human telomerase. Since some normal tissues with high regenerative potential can express hTERT, special attention should be paid to the clinical use of hTERT inhibitors as anti-cancer drugs.

Cloning of human telomerase catalytic subunit (hTERT) gene promoter and identification of proximal core promoter sequences essential for transcriptional activation in immortalized and cancer cells

Telomerase activation is thought to be a critical step in cellular immortalization and carcinogenesis. Of the three major subunits comprising human telomerase, human telomerase catalytic subunit (hTERT) has been shown to be a rate-limiting determinant of the enzymatic activity of human telomerase. However, little is known concerning how expression of hTERT is regulated in human cells. To identify the regulatory elements controlling hTERT gene expression, approximately 3.5 kb of the 5'-flanking sequence of hTERT was cloned and characterized. The promoter of hTERT was GC rich and lacked both TATA and CAAT boxes. The CapSite Hunting method identified transcription start site 19 bp upstream of the first nucleotide of the published cDNA sequence. Transient expression assays revealed that transcription of hTERT was significantly activated in cancer cell lines but repressed in normal primary cells. Using the fibroblast lineage at various stages of transformation, we found that transcription occurred in strains that had overcome replicative senescence and expressed telomerase activity. Deletion analysis of hTERT promoter identified the 181-bp core promoter region upstream of the transcription start site. Gel shift analysis revealed two major factors binding to core promoter, an E box (CACGTG) binding factor and Sp1. Overexpression of c-Myc resulted in a significant increase in transcriptional activity of the core promoter. These findings suggest that hTERT expression is strictly regulated at the transcription machinery, and that the proximal core promoter containing an E box and Sp1 sites is required for transactivation of hTERT.

Human telomerase reverse transcriptase as a critical determinant of telomerase activity in normal and malignant endometrial tissues

Telomerase activation is thought to be essential for cellular immortality and oncogenesis. It is observed in most malignant tumors but not in most normal somatic tissues. Normal human endometrium is, however, known to express significant telomerase activity in a menstrual phase-dependent manner. The 3 major subunits composing telomerase have been identified. Using normal and malignant endometrial tissues, we studied how these components are involved in telomerase activation. A total of 23 endometrial cancers and 32 normal human endometria in various menstrual phases as well as cell lines derived from endometrial cancer were examined for the expression of each telomerase subunit using RT-PCR analysis. Telomerase activity in each sample was determined by the TRAP assay, and the correlation between subunit expression and telomerase activity was examined. RT-PCR analysis revealed that telomerase RNA (hTR) and telomerase-associated protein (TP1) mRNA were constitutively expressed in both normal and malignant endometrial tissues. Expression of human telomerase reverse transcriptase (hTERT) mRNA was observed in most endometrial cancers, while that in normal endometrium depended on the phases of menstrual cycles. Proliferative phase normal endometria expressed hTERT mRNA, while secretory phase endometria did not. There was a strong association between telomerase activity and hTERT expression but not TP1 or hTR expression in both normal and tumor tissues. Five telomerase-positive endometrial cancer cell lines expressed each of the telomerase subunits including hTERT, while 2 telomerase-negative normal primary fibroblast cells expressed TP1 mRNA and hTR, but not hTERT mRNA. Our findings suggest that hTERT is a rate-limiting determinant of enzymatic activity of human telomerase. Since some normal tissues with high regenerative potential can express hTERT, special attention should be paid to the clinical use of hTERT inhibitors as anti-cancer drugs.

Expression of telomerase activity in human endometrium is localized to epithelial glandular cells and regulated in a menstrual phase-dependent manner correlated with cell proliferation

Telomerase activity is observed in most malignant tumors and germ cells, whereas normal somatic cells usually do not express it. Human endometrium is composed of glandular and stromal components and exhibits dramatic changes in proliferative activity during the menstrual cycle, which is exquisitely regulated by estrogen function. We previously reported that normal human endometrium expresses telomerase activity. However, it remains unclear which of the above components are the major sources of telomerase activity and how levels of telomerase activity are regulated over the menstrual cycle. Quantitative analysis of telomerase activity revealed that it changes dramatically over the course of the menstrual cycle and is strictly regulated in a menstrual-phase-dependent manner. Maximal activity equivalent to that in endometrial cancer was present in late proliferative phase, and minimal activity in late secretory phase. Postmenopausal endometrium and endometrium treated with anti-estrogen drugs exhibited decreased telomerase activity. Testing isolated epithelial glandular cells and stromal cells, we found that telomerase activity was localized to epithelial glandular cells. In situ RNA hybridization analysis also revealed epithelial-specific expression of human telomerase RNA. In vitro analysis of cultured epithelial cells demonstrated that telomerase activity is correlated with epithelial proliferation but not affected by estrogen treatment. These findings suggest that expression of telomerase activity is specific to epithelial cells and linked to cell proliferative status. The involvement of estrogen in telomerase regulation remains to be elucidated.