Abstract
Human telomerase reverse transcriptase (hTERT) gene is a biomarker for the targeted therapy in various cancers. Presence of increased telomerase activity is a common feature of all cancers including glioblastoma. Both RNA and catalytic subunits of hTERT are the target sites for blocking its activity. The current study focuses on the expression of hTERT in glioblastoma and its regulation using two different novel siRNAs (small interfering RNA). Our patient data demonstrated increased expression of hTERT, which could be correlated with carcinogenesis in glioma. In vitro studies in siRNA transfected LN18 cells confirmed significant cell death (p < 0.05) as evidenced by MTT and trypan blue exclusion assay. These results were further supported by flow cytometry data, which showed significant increase in early and late apoptosis. The hTERT mRNA expression was effectively downregulated by 45 and 39 % with siRNA1 and siRNA2, respectively. These results were further confirmed by immunoblotting analysis (p < 0.05). Our results suggest that both the siRNAs effectively down regulated the expression of hTERT at mRNA and protein levels, thereby decreasing cell viability and proliferation rate. Hence siRNA mediated downregulation of hTERT could be a potential therapeutic avenue in glioblastoma.
Similar content being viewed by others
References
Andrews LG, Tollefsbol TO (2007) Methods of telomerase inhibition. Methods Mol Biol 405:1–7
Blackburn EH (2001) Switching and signaling at the telomere. Cell 106:661–673
Blackburn EH, Greider CW, Henderson E, Lee MS, Shampay J, Shippen-Lentz D (1989) Recognition and elongation of telomeres by telomerase. Genome 31:553–560
Burnett JC, Rossi JJ, Tiemann K (2011) Current progress of siRNA/shRNA therapeutics in clinical trials. Biotechnol J 6:1130–1146
Cesare AJ, Reddel RR (2010) Alternative lengthening of telomeres: models, mechanisms and implications. Nat Rev Genet 11:319–330
Chiodi I, Mondello C (2011) Telomere-independent functions of telomerase in nuclei, cytoplasm, and mitochondria. Front Oncol 2:133
Cong YS, Wright WE, Shay JW (2002) Human telomerase and its regulation. Microbiol Mol Biol Rev 66:407–425
Counter CM, Hirte HW, Bacchetti S, Harley CB (1994) Telomerase activity in human ovarian carcinoma. Proc Natl Acad Sci USA 91:2900–2904
Cowell JK (1999) Telomeres and telomerase in ageing and cancer. Age 22:59–64
Cunningham AP, Love WK, Zhang RW, Andrews LG, Tollefsbol TO (2006) Telomerase inhibition in cancer therapeutics: molecular-based approaches. Curr Med Chem 13:2875
de Souza Nascimento P, Alves G, Fiedler W (2006) Telomerase inhibition by an siRNA directed against hTERT leads to telomere attrition in HT29 cells. Oncol Rep 16:423–428
Ge L, Shao W, Zhang Y, Qiu Y, Cui D, Huang D, Deng Z (2011) RNAi targeting of hTERT gene expression induces apoptosis and inhibits the proliferation of lung cancer cells. Oncol Lett 2:1121–1129
George J, Banik NL, Ray SK (2009) Combination of hTERT knockdown and IFN-γ treatment inhibited angiogenesis and tumor progression in glioblastoma. Clin Cancer Res 15:7186–7195
George J, Banik NL, Ray SK (2010) Knockdown of hTERT and concurrent treatment with interferon-gamma inhibited proliferation and invasion of human glioblastoma cell lines. Int J Biochem Cell Biol 42:1164–1173
Goodenberger ML, Jenkins RB (2012) Genet adult glioma Cancer Genet 205:613–621
Greider CW (1991) Telomerase is processive. Mol Cell Biol 11:4572–4580
Guittat L, Alberti P, Gomez D, De Cian A, Pennarun G, Lemarteleur T, Mergny JL (2004) Targeting human telomerase for cancer therapeutics. Cytotechnology 45:75–90
Kim TK, Eberwine JH (2010) Mammalian cell transfection: the present and the future. Anal Bioanal Chem 397:3173–3178
Kim NW, Piatyszek MA, Prowse KR, Harley CB, West MD, Ho PDL, Shay JW (1994) Specific association of human telomerase activity with immortal cells and cancer. Science 266:2011–2015
Kotoula V, Barbanis S, Nikolakaki E, Koufoyannis D, Papadimitriou CS, Karkavelas G (2004) Relative expression of human telomerase catalytic subunit (hTERT) transcripts in astrocytic gliomas. Acta Neuropathol 107:443–451
Kurvinen K, Syrjänen S, Johansson B (2006) Long-term suppression of telomerase expression in HeLa cell clones, transfected with an expression vector carrying siRNA targeting hTERT mRNA. Int J Oncol 29:279–288
Langford LA, Piatyszek MA, Shay JW, Schold SC (1995) Telomerase activity in human brain tumours. Lancet 346:1267–1268
Le S, Zhu JJ, Anthony DC, Greider CW, Black PM (1998) Telomerase activity in human gliomas. Neurosurgery 42:1120–1124
Li S, Rosenberg JE, Donjacour AA, Botchkina IL, Hom YK, Cunha GR, Blackburn EH (2004) Rapid inhibition of cancer cell growth induced by lentiviral delivery and expression of mutant-template telomerase RNA and anti-telomerase short-interfering RNA. Cancer Res 64:4833–4840
Li S, Crothers J, Haqq CM, Blackburn EH (2005) Cellular and gene expression responses involved in the rapid growth inhibition of human cancer cells by RNA interference-mediated depletion of telomerase RNA. J Biol Chem 280:23709–23717
Li H, He J, Yi H, Xiang G, Chen K, Fu B, Chen G (2015) siRNA suppression of hTERT using activatable cell-penetrating peptides in hepatoma cells. Biosci Rep 35:1–8
Liu AQ, Ge LY, Lu XL, Luo XL, Cai YL, Ye XQ, Geng FF (2014) Silencing of the hTERT gene by shRNA inhibits colon cancer SW480 cell growth in vitro and in vivo. PLoS One 9:e107019
Maida Y, Masutomi K (2015) Telomerase reverse transcriptase moonlights: therapeutic targets beyond telomerase. Cancer Sci 106:1486–1492
McNamara MG, Sahebjam S, Mason WP (2013) Emerging biomarkers in glioblastoma. Cancers 5:1103–1119
Nakatani K, Yoshimi N, Mori H, Yoshimura SI, Sakai H, Shinoda J, Sakai N (1997) The significant role of telomerase activity in human brain tumors. Cancer 80:471–476
Natarajan S, Chen Z, Wancewicz EV, Monia BP, Corey DR (2004) Telomerase reverse transcriptase (hTERT) mRNA and telomerase RNA (hTR) as targets for downregulation of telomerase activity. Oligonucleotides 14:263–273
Qian X, Cheng J, Chen A, Wang Y, Tao Y, Cao J, Feng Z (2008) Long-term effects of short hairpin RNA-targeted human telomerase reverse transcriptase on suppression of SGC-7901 cell proliferation by inhibition of telomerase activity. Oncol Rep 19:575–581
Sano T, Asai A, Mishima K, Fujimaki T, Kirino T (1998) Telomerase activity in 144 brain tumours. Br J Cancer 77:1633
Saretzki G (2003) Telomerase inhibition as cancer therapy. Cancer Lett 194:209–219
Shammas MA, Koley H, Batchu RB, Bertheau RC, Protopopov A, Munshi NC, Goyal RK (2005) Telomerase inhibition by siRNA causes senescence and apoptosis in Barrett’s adenocarcinoma cells: mechanism and therapeutic potential. Mol Cancer 4:24
Shay JW, Bacchetti S (1997) A survey of telomerase activity in human cancer. Eur J Cancer 33:787–791
Shay JW, Zou Y, Hiyama E, Wright WE (2001) Telomerase and cancer. Hum Mol Genet 10:677–685
Shen H, Sun T, Ferrari M (2012) Nanovector delivery of siRNA for cancer therapy. Cancer Gene Ther 19:367–373
Shervington A, Patel R (2008) Silencing DNA methyltransferase (DNMT) enhances glioma chemosensitivity. Oligonucleotides 18:365–374
Shi YA, Zhao Q, Zhang LH, Du W, Wang XY, He X, Li YL (2014) Knockdown of hTERT by siRNA inhibits cervical cancer cell growth in vitro and in vivo. Int J Oncol 45:1216–1224
Sugita Y, Nakashima A, Kato S, Sakata K, Morimatsu M, Shigemori M (2000) Telomerase activity in gliomas with the use of non-radioisotopic and semi-quantitative procedure for terminal repeat amplification protocol. Oncol Rep 7:1087–1179
Tchirkov A, Rolhion C, Kemeny JL, Irthum B, Puget S, Khalil T, Verrelle P (2003) Clinical implications of quantitative real-time RT–PCR analysis of hTERT gene expression in human gliomas. Br J Cancer 88:516–520
Wang R, Lin F, Wang X, Gao P, Dong K, Wei SH, Zhang HZ (2007) The therapeutic potential of survivin promoter-driven siRNA on suppressing tumor growth and enhancing radiosensitivity of human cervical carcinoma cells via downregulating hTERT gene expression. Cancer Biol Ther 6:1301–1307
Wang T, Xue Y, Wang M, Sun Q (2012) Silencing of the hTERT gene through RNA interference induces apoptosis via Bax/Bcl-2 in human glioma cells. Oncol Rep 28:1153–1158
Westphal M, Lamszus K (2015) Circulating biomarkers for gliomas. Nat Rev Neurol 11:556–566
Zhang W, Xing L (2013) RNAi gene therapy of SiHa cells via targeting human TERT induces growth inhibition and enhances radiosensitivity. Int J Oncol 43:1228–1234
Zhao Y, Ren JL, Zhang R, Ma LY, Bao W, Wang CJ, Yang AG (2005) Study on apoptosis of human cervical carcinoma HeLa cells with RNA interference targeting hTERT. Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi 21:524–526
Acknowledgments
Lavanya Ch was supported by a UGC RGNF-Senior research fellowship (University Grants Commission- Rajiv Gandhi National Fellowship), New Delhi, India. The study was financially supported by DST-SERB (Department of Science and Technology-Science and Engineering Research Board), Government of India. We thank Dr. Pandareesh MD for technical help and data analysis. We thank Dr. Hemanth, Dr. Anu Mary Vargeesh for helping in cell culture work.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that there are no conflicts of interest.
Rights and permissions
About this article
Cite this article
Lavanya, C., Sibin, M.K., Srinivas Bharath, M.M. et al. RNA interference mediated downregulation of human telomerase reverse transcriptase (hTERT) in LN18 cells. Cytotechnology 68, 2311–2321 (2016). https://doi.org/10.1007/s10616-016-0025-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10616-016-0025-8