Quantitative relationship between functionally active telomerase and major telomerase components (hTERT and hTR) in acute leukaemia cells.

Functionally active telomerase is affected at various steps including transcriptional and post-transcriptional levels of major telomerase components (hTR and human telomerase reverse transcriptase (hTERT)). We therefore developed a rapid and sensitive method to quantify hTERT and its splicing variants as well as the hTR by a Taqman real-time reverse transcriptase-polymerase chain reaction to determine whether their altered expression may contribute to telomere attrition in vivo or not. Fresh leukaemia cells obtained from 38 consecutive patients were used in this study. The enzymatic level of telomerase activity measured by TRAP assay was generally associated with the copy numbers of full-length hTERT+alpha+beta mRNA (P=0.0024), but did not correlate with hTR expression (P=0.6753). In spite of high copy numbers of full-length hTERT mRNA, telomerase activity was low in some cases correlating with low copy numbers of hTR, raising the possibility that alteration of the hTR : hTERT ratio may affect functionally active telomerase activity in vivo. The spliced nonactive hTERT mRNA tends to be lower in patients with high telomerase activity, suggesting that this epiphenomenon may play some role in telomerase regulation. An understanding of the complexities of telomerase gene regulation in biologically heterogeneous leukaemia cells may offer new therapeutic approaches to the treatment of acute leukaemia.

Detection of telomerase reverse transcriptase mRNA in biopsy specimens and bile for diagnosis of biliary tract cancers.

Human telomerase reverse transcriptase (hTERT), which codes for the catalytic subunit of telomerase, is essential for telomerase activity. Recent studies revealed that levels of hTERT mRNA as well as telomerase activity are high in neoplasm. The purpose of this study was to correlate the expression of hTERT mRNA with telomerase activity in biopsy specimens and bile from biliary tract cancers and to evaluate the potential diagnostic value of hTERT mRNA analysis for biliary malignancy. We analyzed hTERT mRNA and telomerase activity in biopsy specimens and exfoliated bile cells from patients with cholangiocarcinoma, gallbladder carcinoma and bile duct stones. hTERT was detected by either nested reverse transcriptase-polymerase chain reaction (PCR) or real-time PCR. Telomerase activity was examined by a fluorescence-based telomeric repeat amplification protocol assay. Six of 10 malignant biopsy specimens had detectable hTERT and 7 of 10 had telomerase activity. All cases with hTERT expression had telomerase activity. In bile, 7 of 10 malignant patients had detectable hTERT and 3 of 10 had telomerase activity. Importantly, there were no false positive results in tissue specimens or bile examined in 6 non-cancerous cases. In conclusion, the detection of hTERT mRNA in biopsy specimens and bile cells, in combination with routine histologic and cytologic examination may improve the diagnosis of biliary tract cancers.

Telomerase activity and expression of telomerase RNA component and catalytic subunits in precancerous and cancerous colorectal lesions.

To investigate the role of telomerase activity in colorectal adenoma-carcinomas, telomerase activity, human telomerase RNA component (hTERC) and human telomerase reverse transcriptase (hTERT) mRNA were quantitatively analyzed in human cancerous and precancerous colorectal tissues. Sixty-six colorectal tumor specimens, including 10 invasive carcinomas, 6 mucosal carcinomas and 50 adenomas were evaluated. Ten specimens of normal tissue were also included in the study. Telomerase activity was assayed by semiquantitative fluorescence using the TRAP-eze(TM) telomerase detection kit. Analysis of the expression of each telomerase subunit gene was performed by real-time PCR amplification. There was a positive correlation between histological atypia and telomerase activity (rho = 0.700, p < 0.0001), hTERT mRNA expression (rho = 0.603, p < 0.0001), and hTERC expression (rho = 0.290, p < 0.05). There was also a positive correlation between the levels of hTERT mRNA and telomerase activity (r = 0.455, p < 0.01). Significant differences in the levels of hTERT mRNA were shown between normal tissues and the adenomas (p < 0.05) and between the mucosal carcinomas and invasive carcinomas (p < 0.05). The values of hTERC expression in neoplastic tissues were significantly higher than in the normal tissues; however, there were no significant differences between the adenomas and the carcinomas. In summary, although upregulation of hTERC expression is an early event in adenoma development, hTERT mRNA expression is gradually upregulated during the adenoma-carcinoma sequence and may be a rate-limiting determinant of telomerase activity.

Regression of gastric mucosa-associated lymphoid tissue lymphoma with reduced telomerase activity after eradication of Helicobacter pylori.

Recently, telomerase activity has been demonstrated in a large number of malignant tumors whereas its activity is not detected in most normal somatic cells suggesting its role in the immortalization process. Here we report the first investigation of telomerase activity in a case of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Elevated telomerase activity was detected in biopsy specimens of the lymphoma. After eradication of Helicobacter pylori, the level of telomerase activity returned to normal with histological regression of the lymphoma. The telomerase activity was associated with the disease activity of the gastric MALT lymphoma after eradication therapy in the present case.

Detection of telomerase activity in exfoliated cancer cells obtained from bile.

Telomerase is detected by the telomeric repeat amplification protocol (TRAP) assay in more than 85% of primary cancers. In the present study, we determined telomerase activity using exfoliated bile cells obtained from biliary tract neoplasia specimens. The aim of this study was to provide additional information regarding minimally invasive approaches to the detection of biliary tract cancer in combination with routine cytologic examination. We analyzed for telomerase activity bile juice from patients with gallbladder carcinoma, cholangiocarcinoma, cholecystitis and cholangitis. Semiquantitative determination of telomerase activity was performed using both a fluorescence-based TRAP assay on cell extracts and at the cellular level by an in situ TRAP assay. The fluorescence-based TRAP assay detected bile telomerase activity in samples from 4 of 10 patients with biliary tract cancer. In contrast, the in situ TRAP assay detected telomerase positive cells in samples from 6 of 10 patients with biliary tract cancer. However, only one of these samples showed class V cytology. A combination of semiquantitative analysis and an in situ TRAP assay to detect telomerase positive cells may improve the diagnosis of biliary tract cancers with the combination of routine cytologic examination.

Indomethacin suppresses the growth of colon 26, Meth-A and FM3A tumors in mice by reducing the prostaglandin E2 content and telomerase activity in tumor tissues.

The antitumor effect of indomethacin on Colon 26, Meth-A and FM3A tumors was investigated in mice. The prostaglandin E2 content in tumor tissues was assayed to find out if indomethacin acts on tumors, and the telomerase activity in tumors and somatic tissues (testis, liver, spleen and colon) was also monitored during indomethacin treatment. Growth of Colon 26, Meth-A and FM3A tumors was significantly (P < 0.001-0.05) suppressed by indomethacin compared to the untreated controls. The prostaglandin E2 content in the three tumors was markedly (P < 0.001) reduced by indomethacin. Telomerase activity in Colon 26 and FM3A tumors was significantly (P < 0.001) lower than that of untreated tumors (80% and 45% decrease versus the controls, respectively), and the activity in Meth-A tumor was slightly decreased (10% decrease versus the control) by indomethacin. Telomerase activity in the somatic tissues was not significantly affected by indomethacin. In summary, this study shows the effectiveness of indomethacin as an antitumor agent against three types of tumors, and suggests that indomethacin affects telomerase activity in tumors in vivo.

Telomerase enzyme activity and RNA expression in adriamycin-resistant human breast carcinoma MCF-7 cells.

Telomerase activity has been reported in cancer cells after treatment with antineoplastic agents. Assessment of telomerase activity could be a valuable tool to measure the reduction of aggression caused by chemotherapy. This study was designed to investigate the significance of telomerase for chemotherapy with respect to Adriamycin (ADM)-resistance. MCF-7 and its ADM-resistant line (AdrR) were treated with ADM, 5-fluorouracil (5FU) or taxotere (TAXO). Telomerase activity and human telomerase RNA component (hTR) were quantitatively measured by the telomeric repeat amplification protocol assay and RT-PCR, respectively. Cell counting and MTT assay were also performed. In MCF-7, enzyme activity was significantly reduced by ADM and 5FU treatments. In AdrR, 5FU and TAXO reduced enzyme activity, while ADM significantly increased the activity. No significant changes in hTR were seen in these two cell lines after treatment with any of these drugs. When Bcl-2 expression was examined after drug treatments, ADM increased Bcl-2 expression in AdrR cells, while not changing it in MCF-7 cells. We conclude that an unusual reaction of telomerase activity in AdrR may explain, at least in part, one of the mechanisms of the malignant biological behavior related with the drug-resistance to ADM.

Clinical implications of telomerase activity in resected hepatocellular carcinoma.

This study investigated the relationship of telomerase activity to its clinical implications in hepatocellular carcinoma (HCC). Telomerase activity was quantatively examined by a non-radioisotope quantitative system based on a TRAP-eze (ONCOR) in 42 HCC nodules and 40 non-cancerous liver tissue adjacent to the HCC nodules, obtained by surgical resection. Telomerase activity was confirmed in 37 HCC nodules (88.1%), being more statistically intense in de-differentiated tumors (p<0.01). Telomerase activity was positive in 9 cases (22.5%) of non-cancerous liver tissue and its activation was closely associated with the biologically malignant potential of the tumor itself such as the histological grade, portal vascular invasion, and intrahepatic metastasis (p<0. 05). The disease-free survival rate with its activity was also statistically lower than that without its activity of the non-cancerous tissue (p<0.01). These results indicate that telomerase may be a useful marker of biological characteristics in HCC and may lead to more effective surgical procedures.

Telomerase activity in human renal cell carcinoma.

OBJECTIVE: To determine if telomerase activity plays an important role in the progression of renal cell carcinoma (RCC). MATERIALS AND METHODS: Telomerase activity was measured in 53 tissue samples of RCC (52 patients), 11 samples of normal renal tissue and six tissue samples from benign renal disease using a fluorescence-based telomeric repeat amplification protocol. The activity was assessed for associations with clinical and pathological variables of RCC. To examine the influence of telomerase activity on cell immortalization in vitro, primary cultures of RCC cells were produced; the maximum passage number beyond which cell culture could not be continued was compared with the associated telomerase activity. RESULTS: Among the tissue samples of benign renal disease, one from a patient with a hydronephrotic nonfunctioning kidney had detectable telomerase activity, whereas none of the normal renal tissues had. In 32 of the 53 RCC tissue samples (60%), telomerase activity was detectable, varying from 1.8 to 100.0 TPG units, but was not associated with any clinical or pathological variable such as clinical stage, tumour size, grade or pathological subtype. Telomerase activity also had no association with the maximum passage number of primary cell cultures. CONCLUSIONS: Telomerase activity may not be a prognostic marker for RCC. Alternative mechanism(s) which lengthen telomeres should be considered if maintaining telomere length is considered essential to tumour progression.

Telomerase reverse transcriptase mRNA expression and telomerase activity in hepatocellular carcinoma.

Human telomerase reverse transcriptase (hTERT) has been identified as the catalytic subunit of human telomerase. To clarify the clinical significance of hTERT mRNA in hepatocellular carcinoma (HCC), we investigated the relationship between telomerase activity and hTERT mRNA in human HCC and non-HCC tissues. The hTERT mRNA was detected in 17 (89.47%) of 19 livers with HCC and in 4 (21.05%) of 19 noncancerous tissues from these livers. Telomerase activity was detected in 17 of the 19 tumor tissues (89.47%) and in 4 of the 19 nontumor tissues (21.05%). The hTERT mRNA was detected in all tissues that were telomerase-positive and it was undetected in all tissues that were telomerase-negative. The correlation between the expression of hTERT mRNA and human telomerase activity in this study indicates that hTERT mRNA could be useful to diagnose cancer. Also, as telomerase production may be under the control of hTERT mRNA, the possibility is great that noncancerous liver tissue with chronic liver diseases acquires HCC when the hTERT mRNA is positive.

Improvement in detecting telomerase activity using silica-based resin treatment: An experience of urine in bladder carcinoma.

To improve the telomeric repeat amplification protocol (TRAP) assay to detect telomerase activity using a small amount of sample, we used a resin-column to purify and to concentrate the TS extension DNA sequence. We used 14 samples of naturally voided urine (10 ml) from patients with bladder carcinoma and 9 urine samples from patients with non-malignant urological neoplasias. We used ethylenediamine tetraacetic acid (EDTA) to stabilize telomerase activity and resin treatment to concentrate TS-extended DNA and to exclude PCR inhibitor(s), and then performed extract-based fluorescence TRAP to detect telomerase activity. None of the urinary samples without resin-column treatment had detectable telomerase activity, whereas, in resin-column treated samples, 4/9 (44%) urine samples without EDTA and 9/14 (64%) with EDTA treatment had detectable telomerase activity. A combination of EDTA treatment and resin-column thus may be available to detect telomerase activity using a relatively small amount of secretion fluids, including exfoliated urinary cells.

Levels of telomerase catalytic subunit mRNA as a predictor of potential malignancy.

This study investigated the relationship between the levels of human telomerase reverse transcriptase (hTERT) mRNA and that of telomerase activity in hepatocellular carcinoma (HCC). A significant correlation between hTERT mRNA expression and telomerase activity by transfecting the gene encoding hTERT into telomerase-negative human fibroblast cells has clearly been demonstrated. However, the relationship between levels of telomerase activity and that of hTERT mRNA has yet to be elucidated. In this study, the levels of hTERT mRNA were analyzed in 24 HCC patients by real-time PCR. And the intensity of telomerase activity was analyzed by fluorescence-based TRAP method. The difference of hTERT mRNA level was highly significant between tumor tissues and non-cancerous liver tissues. And there were significant correlations between the levels of hTERT mRNA and that of telomerase activity (r=0.751) in tumor tissues. We observed a strong correlation between levels of hTERT mRNA and that of telomerase activity in HCC. Our results suggest that the levels of hTERT mRNA would be useful in genetic diagnostic tests, instead of telomerase activity, to screen at-risk patients of HCC in human liver tissues.

Effectiveness of indomethacin as an antitumor agent in Colon 26-bearing conventional and nude mice, and telomerase activity in the tumors.

The antitumor effect of indomethacin on Colon 26 tumor was investigated in conventional (CDF1) and nude mice (BALB/c nu/nu), and the telomerase activity in the tumor tissues treated with indomethacin was monitored. Growth of Colon 26 tumor was significantly suppressed with indomethacin treatment compared to the controls both in conventional and nude mice. And telomerase activity in the tumor tissues noticeably declined in contrast to normal somatic tissues (testis, liver and colon), which were not affected by indomethacin treatment. We also showed that indomethacin can suppress tumor growth in association with a preferential decrease in telomerase activity in tumor tissues both in conventional and nude mice to the same extent. This study suggests a method for investigating the mechanism of tumor suppression by indomethacin, and suggests that indomethacin might be useful as a novel agent for human cancer therapy.

Genetic diagnostic test of hepatocellular carcinoma by telomerase catalytic subunit mRNA.

This study investigated the relationship between telomerase activity and telomere length and between telomerase reverse transcriptase (hTERT) mRNA and telomere length. Both cancerous and non-cancerous tissues were studied in individuals with hepatic carcinoma. In this study, the telomere length in HCC livers had a wide range, no clear significant correlation was found between hTERT mRNA and telomere length. Telomerase activity was more strongly correlated with hTERT mRNA than with telomere length. The correlation between hTERT mRNA and telomerase activity shown here indicates that hTERT mRNA has potential for cancer diagnosis.

Surgical significance of telomerase activity in noncancerous liver tissue from patients with hepatocellular carcinoma.

Telomerase activity has been detected in tissue from noncancerous liver of patients with chronic liver disease, but its functional significance remains to be elucidated. We therefore evaluated the telomerase activity in surgically obtained noncancerous liver tissue from 20 hepatocellular carcinoma (HCC) patients. Two samples of noncancerous liver tissue were obtained from each patient: one from the parenchyma adjacent to the HCC nodules of the resected specimen; the other from the parenchyma distant from the HCC nodules of the remnant liver. Telomerase activity was assayed by a non-radioisotope quantitative system based on "TRAP-eze." Five samples from the noncancerous liver tissue adjacent to the HCC nodules (25.0%) were telomerase-positive; all such cases showed high-grade malignant potential, such as intrahepatic metastasis and/or portal vascular invasion and infiltration of the fibrous capsule in the corresponding HCC nodules, and telomerase positivity showed neither a relationship with the histological activity index scores nor a correlation with liver function. Interestingly, no telomerase activity was detected in any of the 20 samples obtained from the parenchyma of the remnant liver. These results indicate that telomerase in noncancerous liver tissue is associated not with the hepatic condition accompanying HCC, but with the biological characteristics of the tumor itself, and may derive from infiltrating cancer cells. Determination of telomerase status may aid in designing more effective surgical procedures.

Negative strand of hepatitis C virus RNA in the liver of patients with chronic hepatitis C after interferon treatment.

In patients receiving interferon therapy for chronic hepatitis C, serum hepatitis C virus (HCV) RNA often reverts from an undetectable to a detectable form after completion of treatment. Detection of the negative strand of HCV-RNA in liver tissue is regarded as an index of viral proliferation. Therefore, we investigated changes in the hepatic negative-strand HCV-RNA following interferon therapy to determine whether this parameter could predict the long-term response to treatment. The subjects of this study were 27 patients with chronic active hepatitis C. Serum positive-strand and hepatic tissue negative-strand HCV-RNA were detected using polymerase chain reaction. At the completion of interferon treatment, serum HCV-RNA was not detected in 21 patients. One year following treatment it remained undetectable in 14 of these patients but it had reverted to a detectable form in seven. The 14 patients in whom hepatic negative-strand RNA was not detected between 2 weeks and 12 months after treatment, had not relapsed after another year. In the 13 remaining patients, negative-strand RNA was found in liver tissue and serum RNA either reverted to a detectable form or remained detectable throughout. From these findings, we conclude that the detection of negative-strand HCV-RNA in liver tissue 2 weeks after the completion of interferon therapy is useful for predicting the long-term effect of therapy.

[Phylogenetic relationships of mastomys to mouse and rat deduced from satellite DNA sequences].

Mastomys is a rodent with a intermediate size between mouse and rat, and classify as a subgenus of Praomys coucha. Our study determined the phylogenetic evolutional relationships of mastomys to mouse and rat deduced from satellite DNA sequences. Genomic DNA was extracted from each liver and digested by restriction enzymes (EcoRI and BglII). After separation and purification, we obtained these EcoRI/BglII-0.5 Kbp repeated elements and determined the nucleotide sequences. The similarities and speed of evolution were 86.06% and 0.1578 between mastomys and mouse, 85.56% and 0.1671 between mastomys and rat, and 83.91% and 0.1863 between rat and mouse, indicating that mastomys was evolutionary classified between mouse and rat, and closely related with mouse.

[Emergency coronary artery bypass grafting with warm blood cardioplegia for a patient with acute myocardial infarction and severe left ventricular dysfunction].

Emergency coronary artery bypass grafting was performed in a 61 year old man who developed acute severe cardiac and respiratory dysfunction after myocardial infarction. At operation cardiac arrest was obtained by warm blood cardioplegia in antegrade intermittent fashion. The left anterior descending artery, diagonal branch, and right coronary artery were revascularized by saphenous vein (SVG). After declamping the aorta, spontaneous heart beating was obtained and postoperative course was uneventful. Postoperative examination showed patent all SVGs and improved cardiac function. Although the delivery of the warm blood cardioplegia was controversial, our recent study revealed that the intermittent antegrade delivery of warm blood cardioplegia showed no ischemic changes of the heart during the procedure.