Human Telomerase Reverse Transcriptase Messenger Research Articles

Human telomerase reverse transcriptase messenger RNA (HTERT MRNA) for hepatocellular carcinoma detection in comparison with galad score

Human telomerase reverse transcriptase messenger RNA (HTERT MRNA) for hepatocellular carcinoma detection in comparison with galad score

New prognostic biomarkers of mortality in patients undergoing liver transplantation for hepatocellular carcinoma.

The outcome prediction of hepatocellular carcinoma (HCC) patients undergoing liver transplantation (LT) was classically established using various macromorphological factors and serum alpha-fetoprotein levels prior to LT. However, other biomarkers have recently been reported to be associated with the prognosis of HCC patients undergoing to LT. This review summarizes clinical data on these new biomarkers. High blood levels of malondialdehyde, total antioxidant capacity, caspase-cleaved cytokeratin-18, soluble CD40 ligand, substance P, C-reactive protein, and vascular endothelial growth factor, increased neutrophil to lymphocyte ratio and platelet to lymphocyte ratio in blood, high peripheral blood expression of human telomerase reverse transcriptase messenger ribonucleic acid, and high HCC expression of dickkopf-1 have recently been associated with decreased survival rates. In addition, high blood levels of des-gamma-carboxy prothrombin, and high HCC expression of glypican-3, E-cadherin and beta-catenin have been associated with increased HCC recurrence. Additional research is necessary to establish the prognostic role of these biomarkers in HCC prior to LT. Furthermore, some of these biomarkers are also interesting because their potential modulation could help to create new research lines for improving the outcomes of those patients.

1037 Serum Human Telomerase Reverse Transcriptase Messenger RNA As a Novel Marker for Pancreatic Ductal Adenocarcinoma

1037 Serum Human Telomerase Reverse Transcriptase Messenger RNA As a Novel Marker for Pancreatic Ductal Adenocarcinoma

Human telomerase reverse transcriptase messenger RNA (TERT mRNA) as a tumour marker for early detection of hepatocellular carcinoma

Background and study aimsHepatocellular carcinoma (HCC) is the fifth most common malignancy in the world. Although tumour markers such as α-foetoprotein (AFP) are widely used and important for HCC detection in clinical scenes, they still do not provide a satisfactory solution to detect HCC at the early stage. The aim of our study was to illustrate the significance of serum human telomerase reverse transcriptase messenger RNA (hTERT mRNA) as a novel biomarker for early detection of HCC. Patients and methodsThirty-five patients with HCC, 15 patients with liver cirrhosis, and 10 healthy subjects were sex and age matched. History taking, full physical examination, and laboratory investigations including liver function tests, hepatitis markers, AFP, and quantification of serum human telomerase reverse transcriptase mRNA (hTERT mRNA) using real-time reverse transcription polymerase chain reaction (RT-PCR) were conducted. Ultrasonography (US), triphasic computed tomography (CT), and liver biopsy were carried out. ResultsThe hTERT was above the cutoff point (>144copies/ml) in 27 HCC patients with a sensitivity of 77.14% and a specificity of 100% and with a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 65.2%. AFP was above the cutoff point (>50ng/ml) in 23 HCC patients with a sensitivity of 65.71% and a specificity of 96% and with a PPV of 96.3% and an NPV of 53.8%.Our study also showed a statistically significant relationship between the size of the tumour in HCC patients and both AFP and hTERT, and hTERT appears to be more correlated with the size of the tumour than AFP. There is no direct correlation between hTERT or AFP and the number of focal lesions with p value >0.05. ConclusionSerum hTERT mRNA is more sensitive and specific than AFP in the early detection of HCC and its level correlates with the size of the tumour.

Quantitative analysis of survivin in colorectal adenocarcinoma: increased expression and correlation with telomerase activity

The aims of the present study are to quantitatively analyze survivin expression, its clinicopathologic roles, and correlation with telomerase activity in a large cohort of patients with colorectal adenocarcinoma. Real-time polymerase chain reaction was used to quantitate expression level of survivin messenger RNA and human telomerase reverse transcriptase messenger RNA (telomerase activity) in 51 patients with colorectal adenocarcinomas. The findings were correlated with the clinicopathologic features of patients, which were prospectively collected into a computerized database. Survivin messenger RNA was expressed in all tumor samples. The level of expression in tumor tissues was increased in comparison with matched nontumor mucosa in the same patient (P = .01). The level of expression of survivin was significantly correlated with the level of human telomerase reverse transcriptase expression (P = .008) and size of the colorectal adenocarcinomas (P = .004). Survival of the patients with colorectal adenocarcinoma was associated with the TNM stages (P = .001) and not with the level of expression of survivin. Thus, survivin activity was altered in colorectal adenocarcinoma. The high prevalence of survivin expression and correlation with telomerase activity are important factors for consideration in gene targeting therapy for colorectal adenocarcinoma.

PD2-2-1: A higher expression of human telomerase reverse transcriptase messenger rna is a favorable prognostic factor in non-small cell lung cancer with human papillomavirus 16/18 E6 protein expression

PD2-2-1: A higher expression of human telomerase reverse transcriptase messenger rna is a favorable prognostic factor in non-small cell lung cancer with human papillomavirus 16/18 E6 protein expression

Effect of RNA interference targeting human telomerase reverse transcriptase on telomerase and its related protein expression in nasopharyngeal carcinoma cells

Analysis of the correlation between telomerase and the expression of its related proteins may provide insight into the molecular mechanism of nasopharyngeal carcinogenesis. We investigated the effect of short hair pin ribonucleic acid (RNA) specific for human telomerase reverse transcriptase messenger RNA on the expression of the proteins c-myc (the transcription factor c-myc is a shortlived nuclear phospho-protein involved in cell proliferation and differentiation, belongs to the myc family), proliferating cell nuclear antigen and Caspase-3 in nasopharyngeal carcinoma cells. Short hairpin RNA expression vectors targeting the messenger RNA of human telomerase reverse transcriptase were constructed. Cells were treated with the short hairpin RNA expression vectors targeting human telomerase reverse transcriptase or vectors that included mismatched short hairpin RNA, and telomerase activity was measured by telomeric repeat amplification enzyme-linked immunosorbent assay. Cell viability was examined using the 3-(4,5-dimethyl thizol-2-yl) 2,5-diphenyl tetrazolium bromide assay. The expression of the three proteins (c-myc, proliferating cell nuclear antigen and Caspase-3) was determined by Western blotting. Short hairpin RNA specific for human telomerase reverse transcriptase messenger RNA significantly inhibited telomerase activity. In addition, the expression of and proliferating cell nuclear antigen were both inhibited, while the expression of Caspase-3 was up-regulated. Our results suggest that short hairpin RNA directed against human telomerase reverse transcriptase inhibits cell viability by regulating telomerase activity and its related proteins expression in nasopharyngeal carcinoma cells. Therefore, RNA interference technology may be a promising strategy for the treatment of nasopharyngeal cancer.

Quantitative determination of human telomerase reverse transcriptase messenger RNA expression in premalignant cervical lesions and correlation with human papillomavirus load

Expression of human telomerase reverse transcriptase (hTERT) messenger RNA (mRNA) and human papillomavirus (HPV)-16 load were quantified using real-time polymerase chain reaction and correlated with cytological findings and the presence of HPV infection in cervical specimens. Human telomerase reverse transcriptase mRNA expression was evaluated in 15 (20.5%) of 73 specimens of atypical squamous epithelial cells of undetermined significance, in 62 (39.7%) of 156 low-grade squamous intraepithelial lesions (LGSILs), in 49 (96%) of 51 high-grade squamous intraepithelial lesions (HGSILs), and in 9 (20%) of 45 normal samples, whereas viral load was quantified in 52 (89.6%) of 58 samples infected with HPV-16. The mean levels of hTERT mRNA expression were 0.11 in normal tissue, 0.23 in atypical squamous epithelial cells of undetermined significance, 0.75 in LGSILs, and 2.5 in HGSILs. Thus, a significant increase in hTERT mRNA expression was observed with increasing degrees of cervical dysplasia. The HPV-16 load was significantly higher in samples of HGSIL than in those of LGSILs (P < .001). A significant correlation was observed between viral load and quantitative hTERT mRNA expression (r = 0.65; P < .05). Quantitative hTERT mRNA assessment showed 96% sensitivity and 100% negative predictive value for high-grade dysplasia, whereas the specificity and positive predictive value were 72% and 36.2%, respectively. It is suggested that quantitative hTERT has a very high sensitivity and negative predictive value, whereas the observed specificity was moderate, indicating that it cannot be used as a diagnostic marker but may be an adjunct in the management of women with high-grade cervical dysplasia. However, the final diagnosis must rely on the inclusion of clinical evaluation and additional assessment data.

Serum Human Telomerase Reverse Transcriptase Messenger RNA as a Novel Tumor Marker for Hepatocellular Carcinoma

We previously reported the usefulness of a qualified highly sensitive detection method for human telomerase reverse transcriptase (hTERT) mRNA in serum with 89.7% sensitivity for hepatocellular carcinoma (HCC). In this study, we developed a quantitative detection method for serum hTERT mRNA and examined the clinical significance in HCC diagnosis. EXPERIMENTAL BACKGROUND: In 64 patients with HCC, 20 with liver cirrhosis, 20 with chronic hepatitis, and 50 healthy individuals, we measured serum hTERT mRNA by using the newly developed real-time quantitative reverse transcription-PCR with SYBR Green I. We examined its sensitivity and specificity in HCC diagnosis, clinical significance in comparison with other tumor markers, and its correlations with the clinical variables by using multivariate analyses. Serum hTERT mRNA showed higher values in patients with HCC than those with chronic liver diseases. hTERT mRNA expression was shown to be independently correlated with clinical variables such as tumor size, number, and degree of differentiation (P < 0.001, each). The sensitivity/specificity of hTERT mRNA and alpha-fetoprotein (AFP) mRNA in HCC diagnosis were 88.2%/70.0% for hTERT and 71.6%/67.5% for AFP, respectively. hTERT mRNA proved to be superior to AFP mRNA, AFP, and des-gamma-carboxy prothrombin in HCC diagnosis. Furthermore, hTERT mRNA in serum was associated with that in HCC tissue. The usefulness of hTERT mRNA expression in HCC diagnosis and its superiority to conventional tumor markers were shown. Therefore, serum hTERT mRNA is a novel and available marker for HCC diagnosis.

Quantitative Assessment of Telomerase Activity and Human Telomerase Reverse Transcriptase Messenger RNA Levels in Pancreatic Juice Samples for the Diagnosis of Pancreatic Cancer

Measurement of telomerase activity is a promising diagnostic tool for pancreatic cancer. Detection of mRNA for human telomerase reverse transcriptase (hTERT), a catalytic subunit of telomerase, is also a diagnostic candidate. In the present study, we developed a telomeric repeat amplification protocol assay with real-time PCR and a protocol for quantification of hTERT mRNA with real-time PCR. To evaluate the feasibility of these methods for diagnosis of pancreatic cancer, we measured telomerase activity and hTERT expression in pancreatic cancer cell lines, pancreatic tissues, and pancreatic juice samples from patients with different pancreatic diseases. There were significant correlations between telomerase activity and hTERT expression in cell lines, tissues, and juice samples. The levels of telomerase activity and hTERT expression were significantly higher in tumoral tissues than in nontumoral tissues. In pancreatic juice specimens, some carcinoma samples showed remarkably high expression of hTERT. However, there were no significant differences in hTERT expression between patients with carcinoma and those with benign diseases, although significant differences in telomerase activity were observed. Our present results suggest that the combined assessment of hTERT and telomerase activities in pancreatic juice provides a potent diagnostic method for pancreatic cancer.

Proteomic Profiling of Pancreatic Cancer for Biomarker Discovery

Pancreatic cancer is a uniformly lethal disease that is difficult to diagnose at early stage and even more difficult to cure. In recent years, there has been a substantial interest in applying proteomics technologies to identify protein biomarkers for early detection of cancer. Quantitative proteomic profiling of body fluids, tissues, or other biological samples to identify differentially expressed proteins represents a very promising approach for improving the outcome of this disease. Proteins associated with pancreatic cancer identified through proteomic profiling technologies could be useful as biomarkers for the early diagnosis, therapeutic targets, and disease response markers. In this article, we discuss recent progress and challenges for applying quantitative proteomics technologies for biomarker discovery in pancreatic cancer.

Lymphocyte telomere dynamics and telomerase activity in inflammatory bowel disease: effect of drugs and smoking

The chromosome instability observed in peripheral blood lymphocytes in ulcerative colitis could be a biomarker of cancer susceptibility. To determine whether accelerated telomere shortening could explain chromosome instability and assess the effect of drugs and smoking on telomere dynamics in these cells. Peripheral blood lymphocytes were isolated from ulcerative colitis, Crohn's disease and non-inflammatory bowel disease control patients. Telomere lengths were measured by quantitative real-time polymerase chain reaction. After activation and cell separation, telomerase activity and human telomerase reverse transcriptase messenger ribonucleic acid were measured by telomerase repeat amplification protocol enzyme-linked immunosorbent serological assay and quantitative real-time polymerase chain reaction, respectively. Age-related telomere loss in peripheral blood lymphocytes was similar in ulcerative colitis, Crohn's disease and control patients. Telomerase activity decreased with age in all groups and correlated positively with telomere length (r = 0.489, P = 0.006). Among Crohn's disease patients, azathioprine was associated with decreased telomerase activity (0.66 vs. 1.54, P = 0.026, P < 0.05) and smoking was associated with decreased human telomerase reverse transcriptase mRNA expression (10.5 vs. 33.3, P = 0.036, P < 0.05). Telomere shortening is not accelerated and therefore cannot be the cause of the chromosome instability observed in ulcerative colitis peripheral blood lymphocytes. Azathioprine and cigarette smoking modify telomerase expression in these cells.

Apoptosis regulating genes, bcl-2 and bax, and human telomerase reverse transcriptase messenger RNA expression in adrenal tumors: Possible diagnostic and prognostic importance

Background. Apoptosis-suppressing gene, bcl-2, and apoptosis-inducing gene, bax, are expressed in various tumors. Human telomerase reverse transcriptase (hTERT) expression is increased in many cancers. The purpose of this investigation was to determine whether bcl-2 or bax gene expression differs between benign and malignant adrenal tumors, and whether hTERT gene expression correlates with the prognosis of patients with adrenal cancer. Methods. Expression of bcl-2 and bax from 52 adrenal surgical specimens was analyzed by reverse transcription-polymerase chain reaction. Expression of hTERT was analyzed by real-time quantitative reverse transcription-polymerase chain reaction, and expressed using the delta-delta threshold cycle method. Results. All normal adrenal tissues (n = 7) and benign adrenal tumors (n = 41) expressed bcl-2 and bax, whereas all adrenocortical cancers (n = 4) expressed bcl-2 but not bax. Expression of hTERT was increased in adrenocortical cancers compared with that in normal tissues (P <.05), cortical adenomas (n = 17) (P <.05), cortical hyperplasias (n = 4) (P <.05), and pheochromocytomas (n = 20) (P <.05). The one patient with an adrenocortical cancer without increased hTERT expression is alive with distant metastasis 5 years after adrenalectomy. The other 3 patients with adrenocortical cancer died 5 to 24 months after adrenalectomy. Conclusions. Expression of bax gene appears to distinguish adrenal cancer from benign adrenal tumors. Gene expression of hTERT should be investigated as a prognostic marker in adrenal cortical cancers. (Surgery 2002;132:1021-7.)

PROSPECTIVE EVALUATION OF GENETIC ABNORMALITIES AND TELOMERASE EXPRESSION IN EXFOLIATED URINARY CELLS FOR BLADDER CANCER DETECTION

To evaluate alternative procedures to cytoscopic examination we prospectively compared noninvasive procedures for detecting bladder cancer namely cytology, loss of heterozygosity (LOH), microsatellite instability and human telomerase catalytic subunit reverse transcriptase (hTERT) messenger (m) RNA detection. Specificity and cutoff values were established in the blood and urine sediment of 50 controls. Sensitivity was analyzed in the urine and tissue samples of 50 patients with bladder cancer. The diagnosis was established by cystoscopic and histological examination. Genomic alterations were studied using a panel of 24 microsatellite markers to detect LOH events, while 3 additional mononucleotide repeats were analyzed for microsatellite instability detection. Telomerase expression was detected in urinary cells by nested RT-polymerase chain reaction amplification of hTERT mRNA. All techniques were compared by cytological examination. Sensitivity and specificity were 31% and 100% for cytological testing, 96% and 100% for LOH, and 75% and 69% for RT-polymerase chain reaction of hTERT, respectively. No alteration was detected on microsatellite instability analysis in urine or tumor tissue cells. Using only the 5 markers most strongly associated with bladder cancer selected by logistic regression analysis, namely ABL1, IFNa, D9S12, MJD58 and D18S364, LOH test sensitivity slightly decreased to 90%. Urinary LOH analysis was the most sensitive and specific method for bladder cancer detection and it appeared less dependent on urine sediment quality. The logistic regression score may be an interesting complement to cystoscopy. The specificity of hTERT mRNA detection was incomplete since false-positives were observed in 31% of cases. Absent microsatellite instability in our cohort showed that these genomic alterations are not present at the early step of bladder cancer.

Evidence for telomerase involvement in the angiogenesis of astrocytic tumors: expression of human telomerase reverse transcriptase messenger RNA by vascular endothelial cells.

Evidence from recent in vitro studies indicates that reactivation of telomerase, the enzyme that synthesizes the telomere ends of chromosomes, is a crucial event in the unlimited clonal expansion of endothelial cells that precedes the neoplastic conversion of these cells. It is known that high-grade gliomas express telomerase and that, in these neoplasms, proliferating endothelial cells may undergo transformational changes with development of sarcomatous components within the primitive tumor. To assess whether telomerase is involved in the endothelial cell proliferation that characterizes brain tumor angiogenesis, the authors investigated at the single-cell level the expression of messenger (m)RNA for the human telomerase catalytic subunit human telomerase reverse transcriptase (hTERT) by vascular cells of astrocytic tumors. The in situ hybridization (ISH) method was performed by processing histological sections with specific riboprobes for hTERT and for c-myc, an oncogene that is known to upregulate hTERT. Results of the ISH studies were compared with proliferative activity, as estimated by Ki-67 immunostaining. The expression of hTERT mRNA by vascular endothelial cells was related to the histological grade of the tumor because it was detected in five (29%) of 17 low-grade astrocytomas, nine (56%) of 16 anaplastic astrocytomas, and 19 (100%) of 19 glioblastomas multiforme (GBMs). Expression of c-myc mRNA was strictly correlated with that of hTERT mRNA. In low-grade astrocytomas and anaplastic astrocytomas, a dissociation was noted between hTERT mRNA expression and the proliferation rate of endothelial cells. Conversely, GBMs displayed a significant correlation between the level of hTERT mRNA expression and endothelial cell proliferation. Data from an in vitro assay in which human umbilical vein endothelial cells were stimulated to proliferate by adding vascular endothelial growth factor and an ISH study of newly formed vessels surrounding brain infarcts confirmed that expression of hTERT mRNA does not merely reflect the proliferative status of endothelial cells but represents a specific feature of brain tumor neovascularization. The results of this study are consistent with a role of telomerase in the angiogenesis of astrocytic tumors. Expression of hTERT mRNA by tumor vascular cells is an early event during the progression of astrocytic tumors, which precedes endothelial cell proliferation and may represent a first sign of dedifferentiation. Other than elucidating the mechanisms of tumor angiogenesis, these results encourage research on antitelomerase drugs for the treatment of malignant gliomas.

Comparison of Human Telomerase Reverse Transcriptase Messenger RNA and Telomerase Activity as Urine Markers for Diagnosis of Bladder Carcinoma

Comparison of Human Telomerase Reverse Transcriptase Messenger RNA and Telomerase Activity as Urine Markers for Diagnosis of Bladder Carcinoma

Comparison of Human Telomerase Reverse Transcriptase Messenger RNA and Telomerase Activity as Urine Markers for Diagnosis of Bladder Carcinoma

Comparison of Human Telomerase Reverse Transcriptase Messenger RNA and Telomerase Activity as Urine Markers for Diagnosis of Bladder Carcinoma