Tehran University Medical Journal

Background: Transitional Cell Carcinoma (TCC) of bladder is the second most common urogenital malignancy and because of its high rate of recurrence (two third of tumors recur) vigilant surveillance is necessary. There have been a lot of efforts to find a proper biomarker for detecting urothelial cancers because available methods are expensive and invasive (like cystoscopy) or have a low degree of sensitivity (like urine cytology). Urothelial malignancies, like other cancers tend to express a large amount of telomerase. The aim of this study was to evaluate the possible application of voided urine human telomerase reverse transcriptase (hTERT) mRNA assay in detecting low-grade bladder carcinoma in comparison with urine cytology.

Methods: Voided urine samples were collected from 49 patients who were supposed to go under operation. Samples were examined by both Quantitative Real-time RT-PCR (for measuring hTERT mRNA level) and cytology the results were then compared to the final pathologic studies.

Results: Regardless of clinical stage and or pathological grade of tumor, sensitivity of telomerase test and urine cytology was 74% and 16% respectively. There was a strong correlation between results of urine cytology and stage and/or grade of tumor however, sensitivity of telomerase test was acceptable regardless of stage and or grade of tumor. There was a statistically significant difference between sensitivity of urine cytology and telomerase test (p<0.001).

Conclusion: Detection of hTERT-mRNA can potentially be used as a non-invasive method for diagnosis and follow up of bladder carcinoma instead of urine cytology.

Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Telomere, by which is a terminal structure of eukaryotic chromosomes was discovered at first in 1938 and has a vital role in chromosome protection. Telomere in human and other vertebrates consists of thousands of 5′-TTAGGG-3′ tandem repeats at the end of the chromosome, has a main role in the chromosome stability. Telomere protects the end of the chromosome from degeneration, rearrangement and end to end fusion. There is a telomere loss at every cell division. Progressive loss in telomere length results in disassociation of telomere binding proteins and change in gene expression profiles. Adjacent genes are suppressed by the telomere effect so the telomere loss results in adjacent gene expressions. Apoptosis and replicative senescence are caused by progressive telomere loss. There are three mechanisms for increasing telomere length in eukaryotes and telomerase is the predominant mechanism. Telomerase can synthesize telomere, without the template. Telomerase is overexpressed In 90% of cancers. Therefore cancerous cells compensate the telomere loss in every cell division because of telomerase. In conclusion, telomerase is a proper target for cancer therapy and many methods including direct inhibition of telomerase and immunotherapy have been introduced.

Background: Human papilloma virus (HPV) is one of the most important factors in cervical cancer. Viral sequences are integrated into the host cell genome. In mild cases the virus causes skin damages, in severe cases it leads to cancer. Like many other cancers, telomerase gene expression was increased in cervical cancer. This enzyme is a reverse transcriptase that contains two common subunits: i) catalytic protein called human telomerase reverse transcriptase (hTERT) and, ii) RNA sequence called hTR. hTERT expression is hardly found in any somatic tissues. Detection of high telomerase activity in human cells, lead to tumor genesis. So hTERT can be used as a diagnostic tool in cancer detection.

Methods: This experimental study was carried out from May 2013 to April 2014 in Nanobiotechnology Research Center, Baqiyatallah University of Medical Sciences in Tehran, Iran. Caski and Hela cancer cell lines were used which contain HPV16 and HPV18 respectively. Cell lines were cultured and total RNA was extracted. Following normalization agent glyceraldehyde-3-phosphate dehydrogenase (GADPH), hTERT expression level was determining by real-time PCR method. For each sample, the expression level of hTERT and GAPDH were quantified as copy numbers (per reaction) using the standard curve. Finally, hTERT levels in Hela and Caski cell lines were compared quantitatively by t-test using GraphPad statistic software version 5 (San Diego, CA, USA).

Results: According to the charts real-time PCR, hTERT gene expression in Hela and Caski cancer cell lines is significantly different (t=0.0319).

Conclusion: All results confirm that hTERT expression levels in Hela and Caski cell lines are significantly different and the level of hTERT expression in the Caski cell line was slightly higher than that of Hela cell line. The significant difference between hTERT mRNA expression levels reported here could be used as a tumor marker for HPV16 and HPV18 in cervical cancer.

Background: Telomerase as an enzyme with reverse transcriptase activity has an essential role in telomere maintenance by adding a telomere repeat sequence to the 3' end of chromosome and is important for regulating of many processes in embryonic development including cell proliferation and differentiation. Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) with a self-renewal capacity are cells that can differentiate into various germ layer derivatives including neural cells and cardiomyocytes, and undergo biological changes during long-term cultivation. Hence, the passage number in which the cells expanded seems to be very important for proliferating and differentiating. This study was aimed at investigating the relationship between the telomerase activity and the growth rate of (hUC-MSCs) at different passages.

Methods: This experimental study was performed in Ardabil University of Medical Sciences, Iran, from March 2014 to December 2014. The umbilical cord samples were obtained from full-term neonate hospitalized in Alavi’s Hospital in Ardabil under sterile conditions. The umbilical vessels were clear off and the small pieces of the umbilical cord were cultured in Dulbecco's modified eagle's medium (DMEM) supplemented with 20% fetal bovine serum (FBS). Then, the hUC-MSCs were harvested from passage one to three to calculate the population doubling time (PDT) and extract proteins by using CHAPS lysis buffer. Finally, the telomerase activity of the cells at different passages was measured by telomeric repeat amplification protocol (TRAP) and qRT-TRAP assays.

Results: The hUC-MSCs population doubling time at passage from 1 to 3 were calculated as the average of 54.68±1.92, 55.03±1.71 and 69.41±2.54 hours, respectively, suggesting the higher cell passage number, the more extended PDT. The threshold cycles (CTs) for the telomerase activity also showed 30.58±0.51, 27.24±0.74 and 32.13±0.75 for the cell passage from one to three, respectively, representing the significant increasing in telomerase activity at passage two compared with the other passages (P= 0.021).

Conclusion: Analysis of the growth curve, PDT determination and measurement of telomerase activity of the human umbilical cord-derived mesenchymal stem cells showed that the long-term cell culture can affect on the cell proliferation and the telomerase activity.