Telomerase activity in esophageal squamous cell carcinoma and lesions unstained with Lugol's solution

BACKGROUND/AIMS: Telomerase is a ribonucleoprotein enzyme that protects erosion of telomeres at the ends of chromosomes and its activity has been detected in immortalized cells and most human cancers. METHODOLOGY: We analyzed telomerase activity in primary esophageal squamous cell carcinomas (SCCs) without any preoperative treatment and lesions unstained with Lugol's solution, using a telomeric repeat amplification protocol (a TRAP) assay. RESULTS: Strong telomerase activities were detected in all resected specimens of esophageal SCCs, and in 33 of 40 endoscopic biopsy specimens of lesions unstained with Lugol's solution. Among lesions unstained with Lugol's solution, 19 of 19 esophageal SCCs, and 13 of 13 dysplasias, which are considered as clinically precancerous lesions had strong telomerase activities. CONCLUSIONS: These results indicate that reactivation of telomerase may occur at an early stage in the carcinogenesis of esophageal SCCs, and telomerase activity may be a practically useful molecular biological marker for supporting the diagnosis of early esophageal SCCs.     

Telomerase activity in HeLa cervical carcinoma cell line proliferation

Normal human somatic cells in culture have a limited dividing potential. This is due to DNA end replication problem, whereby telomeres shorten with each subsequent cell division. When a critical telomere length is reached cells enter senescence. To overcome this problem, immortal HeLa cell line express telomerase, an enzyme that prevents telomere shortening. Although immortal, the existence of non-dividing cells that do not incorporate ³H-thymidine over 24 h of growth has been well documented in this cell line. Using DiI labeling and high-speed cell sorting, we have separated and analyzed fractions of HeLa cells that divided vigorously as well as those that cease divisions over several days in culture. We also analyzed telomerase activity in separated fractions and surprisingly, found that the fraction of cells that divided 0–1 time over 6 days in culture have several times higher endogenous telomerase activity than the fastest dividing fraction. Additionally, the non-growing fraction regains an overall high labeling index and low SA-β-Gal activity when subcultured again. This phenomenon should be considered if telomerase inhibition is to be used as an approach to cancer therapy. In this paper we also discuss possible molecular mechanisms that underlie the observed results.     

胰腺癌患者手术标本及胰液脱落细胞端粒酶活性的检测

目的 研究胰腺良，恶性患者手术标本，经ERCP所获胰液脱落细胞的端粒酶活性的表达，探索胰腺癌诊断的新方法。方法 采用TRAP-ELISA的方法检测胰腺癌细胞株，胰腺良恶性疾病组织物，胰液细胞的端粒酶活性。结果 6株胰腺癌细胞株均检测到了端粒酶活性，胰腺癌手术标本端粒酶的阳性率为63%（5/8），而4例正常胰腺组织和2例胰腺良性疾病患者的胰腺标本未检测到端粒酶活性，胰腺癌患者的胰液细胞中，有58%（11/19）检测到有端粒酶活性的表达，而胰腺良性疾病也有高达62.5%(5/8)的阳笥率，两者无差别。结论 胰腺癌组织标本中有较高的端粒酶活性表达；胰液脱落细胞检测端粒酶活性无助于鉴别胰腺良恶性疾病。     

Telomerase activity and survival of late-stage South African esophageal carcinoma patients.

Squamous cell carcinoma of the esophagus is a cancer with a high incidence in South Africa. We have investigated the prognostic value of telomerase activity in tumors as well as nearby normal tissue. Biopsies from 98 patients (71 men and 27 women) were analyzed using an adaptation of the TRAP assay. We found all tumor biopsies to have moderate to high telomerase activity, while one third of biopsies from normal mucosa were negative. The telomerase activity level of the tumors had no prognostic value (P = 0.95) as determined by the log rank test. A P-value of 0.02 was found when the telomerase-negative and moderately positive normal biopsies were grouped together and compared to those with high activity. Our results show that telomerase activity of normal mucosa in the vicinity of the tumor can identify a population of patients with significantly worse prognosis, even in late stage patients.     

Telomerase activity correlates with cell cycle regulators in human hepatocellular carcinoma

AIMS/BACKGROUND: Mutation in cell cycle genes is the most common genetic change in malignant tumor cells. Telomerase activation, considered as essential in the immortality of cancer cells, is found in most cancers, where there may be an association with an active cell cycle. METHODS: In this study study we used the TRAP assay to determine telomerase activity in liver tumor specimens from 25 cases of hepatocellular carcinoma (HCCs) as well as in corresponding non-cancerous liver tissue in each patient. The expression of cyclin D1, cdk2, and cdk4 protein was also examined by Western blot. RESULTS: Twenty-one of the 25 cases of HCC were found to have increased telomerase activity, whereas only five out of the 25 non-cancerous liver samples were found to have weak telomerase activity. Telomerase activity was not found to be related to tumor size, HBsAg, HBeAg, anti-HCV, transaminase, or alpha-fetoprotein serum titer. Furthermore, three out of the 25 cases of HCC showed cyclin D1 overexpression, whereas 15 of the 23 cases of HCC showed decreased cyclin D1 expression. Down regulation of cyclin D1, cdk2, cdk4 protein correlated with telomerase activity (p<0.004, p<0.013, and p<0.001 respectively). CONCLUSION: The results indicate that genetic defects in HCC facilitate the reactivation of telomerase activity, a process which may be dependent on cyclin D1 with its cyclin dependent kinase (cdk) partner defect.     

Telomerase activity in human ovarian carcinoma.

Telomeres fulfill the dual function of protecting eukaryotic chromosomes from illegitimate recombination and degradation and may aid in chromosome attachment to the nuclear membrane. We have previously shown that telomerase, the enzyme which synthesizes telomeric DNA, is not detected in normal somatic cells and that telomeres shorten with replicative age. In cells immortalized in vitro, activation of telomerase apparently stabilizes telomere length, preventing a critical destabilization of chromosomes, and cell proliferation continues even when telomeres are short. In vivo, telomeres of most tumors are shorter than telomeres of control tissues, suggesting an analogous role for the enzyme. To assess the relevance of telomerase and telomere stability in the development and progression of tumors, we have measured enzyme activity and telomere length in metastatic cells of epithelial ovarian carcinoma. We report that extremely short telomeres are maintained in these cells and that tumor cells, but not isogenic nonmalignant cells, express telomerase. Our findings suggest that progression of malignancy is ultimately dependent upon activation of telomerase and that telomerase inhibitors may be effective antitumor drugs.     

Long-term survivors after the resection of limited esophageal small cell carcinoma

Patients with small cell carcinoma of the esophagus have a poor prognosis and have generally been treated by chemotherapy. However, all reported cases were at advanced stages. We need to establish an adequate treatment for patients with small cell carcinoma of the esophagus with invasion limited to the submucosal layer. In this paper, five cases of small cell carcinomas, which accounted for 2.8% of 180 surgically treated esophageal carcinomas, were reviewed for pathological findings, treatment, and outcome. Among three patients who had a small cell carcinoma of the esophagus with invasion limited to the submucosal layer, two patients survived for 7 and 9 years after surgery with no evidence of the disease. One of them was treated using surgery alone. Consequently, surgery may be considered as a possible choice of treatment for small cell carcinoma of the esophagus with invasion limited to the submucosa.     

Genes associated with telomerase activity levels in esophageal carcinoma cell lines

Telomerase activity levels have been shown to correlate with tumor progression in several malignancies. However, the genetic regulation of telomerase activity levels is not fully understood. The aim of the present study has been to identify a gene expression profile, predicting correlation with the telomerase-activity test. Ten human esophageal carcinoma cell lines were investigated using the telomerase activity assay (TRAPeze) Telomerase Detection Kit), followed by further characterization using the GeneChip Human Genome U133A 2.0 Array (Affymetrics Inc., USA), including 14 500 human genes. Telomerase activity levels were detected in all cell lines with a broad range of activity levels. Using a high correlation coefficient, r > 0.90, the following genes were found to be positively correlated with telomerase activity levels: N-myristoyltransferase 2; ribosomal protein L3; retinoblastoma-like 2 (pRb2/p130); and cyclin G2. Only one gene was negatively correlated with telomerase activity levels, zinc finger protein 207. In conclusion, the present microarray data provide primary validation data indicating possible candidates for prognostic and prediction factors in esophageal cancer in relation to telomerase activity.     

Long-surviving case of advanced esophageal small cell carcinoma with a multidisciplinary treatment approach

A 64-year-old man presented with dysphagia and heartburn. Upper gastrointestinal endoscopy showed an irregular type 2 tumor of the lower esophagus. Histological examination of the biopsy specimen revealed undifferentiated carcinoma, small cell type. Subtotal esophagectomy was performed. Two months after the initial surgery, an intradural extramedullary metastasis was found, and tumorectomy was performed. Eight months after the initial surgery, lymph node metastases were found, and alternate-week administration of CPT-11 was begun. Thirteen months after the initial surgery, an oropharyngeal metastasis was identified for which he received radiation therapy with a total dose of 45 Gy. One month later, abdominal CT scan showed multiple liver metastases and a left adrenal metastasis. He received CPT-11 for another 12 months, but eventually succumbed to his disease 30 months after the initial diagnosis. Our case suggests that controlling each of the recurrent lesions with various treatment modalities might lead to prolonged survival.     

Telomerase activity in hepatocellular carcinoma as a predictor of postoperative recurrence

Telomerase is a ribonucleoprotein that stabilizes telomeres and allows unlimited cell division. It has been reported that most cancer cells evince reactivated telomerase. We examined telomerase activity in 29 patients with hepatocellular carcinoma (HCC) by a polymerase chain reaction-based semiquantitative assay. Of 24 HCCs, telomerase activity was positive in 23 (95,8%), of which 16 showed strong activity. In 11 well differentiated HCCs, telomerase activity was strong in 5, weak in 5, and undetected in 1 and in 13 moderately differentiated HCCs, it was strong in 11 and weak in 2. Five of 6 HCCs less than 2 cm in diameter expressed strong telomerase activity, while weak telomerase activity was detected in 7 of 19 (36.8%) resected noncancerous liver tissues from the HCC patients. Five of these 7 patients (71%) manifested recurrence within 6 months after surgery. The recurrence rate in these patients whose noncancerous liver tissue was positive for telomerase activity was significantly higher than that in patients in whom it was negative (P=0.017). These results suggest that the presence of telomerase activity may be a useful diagnostic marker of HCC, regardless of tumor size, and that its detection in resected noncancerous liver tissues may serve as a useful predictor of postoperative recurrence.     

Radiation-induced esophageal squamous cell carcinoma in situ

A report of radiation-induced squamous cell carcinoma in situ of the esophagus is presented. This report indicates that the patient developed the carcinoma in situ many years after chest wall irradiation for breast cancer treatment. A review of the literature with respect to carcinogenesis after radiotherapy is included and recommendations for the follow-up of patients having mediastinal radiation are suggested.     

Synchronous esophageal and renal cell carcinoma

Multiple cancer associated with esophageal cancer is not uncommon; however, synchronous esophageal and renal cell carcinoma is very rare. Only three cases have been reported to date, and one of these patients was treated in our institution. We have since successfully treated another patient. Here, we report the two cases treated in our institution. In the first case, esophagectomy, nephrectomy, and reconstruction using a gastric tube were carried out in one stage. Post-operative renal function was temporarily impaired by the complications of anastomotic leakage and pyothorax but no hemodialysis was needed. In the second case, as the patient had undergone distal gastrectomy because of gastric cancer, we chose a two-stage operation, i.e. esophagectomy and nephrectomy as the first stage, followed by reconstruction using a colon substitute after 4 weeks, resulting in only slight renal dysfunction. Patients 1 and 2 are alive and well 7 years and 2 years after the operations respectively.     

Synchronous solitary small intestinal metastasis from esophageal squamous cell carcinoma: report of a case

A 69-year-old male was referred to our hospital with squamous cell carcinoma of the lower thoracic esophagus and a chief complaint of vomiting. On positron emission tomography, fluorodeoxyglucose accumulation was detected in the primary tumor and paraesophageal lymph node. Thoracic esophagectomy and 3-field lymphadenectomy were performed following the administration of neoadjuvant chemotherapy composed of fluorouracil plus cisplatin. Intraoperatively, during the catheter jejunostomy procedure for enteral nutrition, a jejunal nodule measuring 1.5 cm in size at 35 cm distal from the Treitz ligament was detected. The nodule was completely resected using partial jejunotomy. A submucosal tumor-like elevated lesion was seen in the resected specimen. Histologically, squamous cell carcinoma invaded the muscularis propria. Lymphovascular permeation was observed. The patient’s postoperative course was uneventful, and he was discharged on postoperative day 25. After 4 months, CT showed recurrence of multiple liver metastases. Unfortunately, the patient died 6 months after the operation.     

Expression and prognostic significance of esophageal squamous cell carcinoma associated long non-coding RNA-1 in esophageal squamous cell carcinoma

正Objective To analyze the expression and prognostic significance of esophageal squamous cell carcinoma associated long non-coding RNA-1 (ESCCAL-1) in esophageal squamous cell carcinoma (ESCC) tissues.Methods From August 2011 to May 2013, 73 patients with ESCC,who received radical resection in the First Affiliated Hospital of Zhengzhou University and Henan Cancer Hospi-     

Correlation between expression of human telomerase subunits and telomerase activity in esophageal squamous cell carcinoma

AIM: To investigate telomerase activity and hTERT, TP-1 expression and their relationships in esophageal squamouscell carcinoma (ESCC).METHODS: Telomerase activity was measured in 60 ESCCtissues using telomeric repeat amplification protocol (TRAP)assay by silver staining. In situ hybridization was used for detecting hTERT and TP-lmRNA.RESULTS: The telomerase activity was detected in 83.3 % of ESCC tissues. The difference of telomerase activity was significant between well and poorly cancer differentiated lesions (P<0.05). The positive rate of telomerase activity was higher in patients with lymphatic metastasis than in patients without lymphatic metastasis. In cancer tissues hTERT mRNA expression was 75 % and TP-1 mRNA expression was 71.7 %. The expression of hTERT, TP-1 mRNA in well and poorly differentiated carcinoma was not significant. The expression of hTERT mRNA was correlated with telomerase activity, but TP-1 mRNA expression was not correlated with it.CONCLUSION: Telomerase activity and hTERT, TP-1 mRNA expression are up-regulated in ESCC. Telomerase activity in ESCC is correlated with lymphatic metastasis and cancer differentiation. Telomerase activity may be used as a prognostic marker in ESCC. hTERT mRNA expression is correlated with telomerase activity. Enhanced hTERT mRNA expression may initially comprehend the telomerase activity level, but it is less sensitive than TRAP assay.