Development and characterization of a monoclonal antibody directed against human telomerase reverse transcriptase (hTERT)

Telomerase: A prominent oncological target for development of chemotherapeutic agents

Telomerase is a ribonucleoprotein (RNP) responsible for the maintenance of chromosomal integrity by stabilizing telomere length. Telomerase is a widely expressed hallmark responsible for replicative immortality in 80-90% of malignant tumors. Cancer cells produce telomerase which prevents telomere shortening by adding telomeres sequences beyond Hayflick's limit; which enables them to divide uncontrollably. The activity of telomerase is relatively low in somatic cells and absent in normal cells, but the re-activation of this RNP in normal cells suppresses p53 activity which leads to the avoidance of senescence causing malignancy. Here, we have focused explicitly on various anti-telomerase therapies and telomerase-inhibiting molecules for the treatment of cancer. We have covered molecules that are reported in developmental, preclinical, and clinical trial stages as potent telomerase inhibitors. Apart from chemotherapy, we have also included details of immunotherapy, gene therapy, G-quadruplex stabilizers, and HSP-90 inhibitors. The purpose of this work is to discuss the challenges behind the development of novel telomerase inhibitors and to identify various perspectives for designing anti-telomerase compounds.

Telomerase Activity Analysis In Urine Sediment for Bladder Cancer

Bladder cancer with an incidence of 15 cases per 100,000 persons in the global population is the most common tumor of the urinary tract. Imaging techniques, cytoscopy, and cytology are not sufficiently accurate to detect early stage tumors, and the need for new diagnostic markers is still an urgency. Among the biomarkers most recently proposed to improve diagnostic accuracy and especially sensitivity, increasing attention has been focused on the role of the ribonucleoprotein, telomerase. Previous studies have shown that the quantitative telomerase repeat amplification protocol (TRAP) assay performed in voided urine is an important noninvasive tool for the diagnosis of bladder tumors since it has very high sensitivity and specificity, even for early stage and low-grade tumors. Telomerase activity in urine determined by TRAP seems to be marker of great potential, even more advantageous in cost-benefit terms when used in selected symptomatic patients or professionally high-risk subgroups. Here we report the real-time PCR protocol to detect telomerase activity in urine sediment for bladder cancer.

The current role of telomerase in the diagnosis of bladder cancer

Bladder cancer has an incidence of 15 cases per 100,000 persons in the global population and is the most common tumor of the urinary tract. Imaging techniques, cytoscopy, and cytology are either invasive or not sufficiently accurate to detect early stage tumors, and the need for new diagnostic markers still remains. Among the markers most recently proposed to improve diagnostic accuracy and especially sensitivity, increasing attention has been focused on the role of the ribonucleoprotein, telomerase. Relevant papers on the etiology, diagnosis, and evaluation of bladder cancer using telomerase in urine were searched for and considered. The PubMed search was performed using the text terms "bladder cancer", "diagnosis", and "telomerase". Previous studies have shown that the quantitative Telomerase Repeat Amplification Protocol (TRAP) assay performed in voided urine is an important non-invasive tool for the diagnosis of bladder tumors since it has very high sensitivity and specificity, even for early stage and low grade tumors. The main limitation of this test is the rate of false positive results due to the presence of inflammatory or non-tumor cells (i.e., epithelial cells from the lower genital tract), which express telomerase activity (TA). Consequently, an in situ analysis would seem to be important to identify the nature of telomerase-positive cells. Immunocytochemical detection of the hTERT subunit by a specific antibody seemed to open up the possibility to identify different cellular components of urine. However, the lack of a strict relationship between hTERT protein expression and telomerase activity has, to a certain extent, made this approach less relevant. In conclusion, telomerase activity in urine determined by TRAP seems to be marker of great potential, even more advantageous in cost/benefit terms when used in selected symptomatic patients or professionally high-risk subgroups.