Abstract
Telomeres are protective chromosomal ends that shield the chromosomes from DNA damage,
exonucleolytic degradation, recombination, and end-to-end fusion. Telomerase is a ribonucleoprotein
that adds TTAGGG tandem repeats to the telomeric ends. It has been observed that 85 to 90% of human
tumors express high levels of telomerase, playing a crucial role in the development of cancers. Interestingly,
the telomerase activity is generally absent in normal somatic cells. This selective telomerase expression
has driven scientists to develop novel anti-cancer therapeutics with high specificity and potency.
Several advancements have been made in this area, which is reflected by the enormous success of
the anticancer agent Imetelstat. Since the discovery of Imetelstat, several research groups have contributed
to enrich the therapeutic arsenal against cancer. Such contributions include the application of new
classes of small molecules, peptides, and hTERT-based immunotherapeutic agents (p540, GV1001,
GRNVAC1 or combinations of these such as Vx-001). Many of these therapeutic tools are under different
stages of clinical trials and have shown promising outcomes. In this review, we highlight the current
status of telomerase-based cancer therapeutics and the outcome of these investigations.
Keywords:
Telomeres, hTERT, Telomerase inhibitors, Clinical trials, Cancer therapy, Vaccines.
Graphical Abstract
[103]
Röth, A. Harley, C.B.; Baerlocher, G.M. Small Molecules in Oncology; Springer: Berlin, 2010, pp. 221-234.
[106]
Kozloff, M.; Sledge, G.; Benedetti, F.; Starr, A.; Wallace, J.; Stuart, M.; Gruver, D.; Miller, K. Phase I study of imetelstat (GRN163L) in combination with paclitaxel (P) and bevacizumab (B) in patients (pts) with locally recurrent or Metastatic Breast Cancer (MBC) J. Clin. Oncol., 2010, 28(15_suppl), 2598-2598.
[135]
Brunsvig, P.; Gjertsen, M.; Kvalheim, G.; Aamdal, S.; Markowski-Grimsrud, C.; Sve, I.; Dyrhaug, M.; Trachsel, S.; Møller, M.; Eriksen, J. A phase I/II study of telomerase peptide vaccination of patients with non-small cell lung cancer. J. Clin. Oncol., 2005, 2580-2580.
[146]
Lencioni, R. Seminars in liver disease; Thieme Medical Publishers: New York, 2010, 30, p. 052-060.
[164]
Gridelli, C.; Ciuleanu, T.; Gomez, M.D.; Szczesna, A.; Bover, I.; Dols, M.C.; Kentepozidis, N.; Viteri, S.; Manegold, C.; Khayat, D. LBA52Randomized double blind phase IIb trial in advanced NSCLC patients who did not progress after first line platinum based chemotherapy: Vx-001, a therapeutic cancer vaccine, vs. placebo as maintenance therapy. Ann. Oncol., 2017, 285.
[184]
Vonderheide, R.H.; Aggarwal, C.; Bajor, D.L.; Goldenberg, J.; Loch, C.; Lee, J.C.; Yan, J.; Morrow, M.P.; DeMichele, A.; Langer, C. J Study of hTERT and IL-12 DNA immunotherapy using electroporation in patients with solid tumors after definitive surgery and adjuvant therapy. J. Clin. Oncol., 2015, 33, TPS3104