J Korean Med Sci.  2007 Sep;22(Suppl):S73-S78. 10.3346/jkms.2007.22.S.S73.

Change of the Expression of Human Telomerase Reverse Transcriptase mRNA and Human Telomerase RNA after Cisplatin and 5-Fluorouracil Exposure in Head and Neck Squamous Cell Carcinoma Cell Lines

• Lee BJ
• Lee BH
• Wang SG
• Lee JC
• Roh HJ
• Goh EK
• Kim CM
• Jun ES

• KMID: 1785792
• DOI: http://doi.org/10.3346/jkms.2007.22.S.S73

Abstract

Telomerase activity appears to be associated with cell immortalization and malignant progression. Understanding how telomerase activity is regulated in vivo is important not only for understanding the molecular biology of telomerase but also for the potential clinical application of anticancer drugs. This study evaluated telomerase activity and quantified the expression of human telomerase reverse transcriptase (hTERT) mRNA and human telomerase RNA (hTR) using a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) method before and after the exposure of cisplatin and 5-fluorouracil (5-FU) in two head and neck squamous cell carcinoma (HNSCC) cell lines. Two human HNSCC cell lines (PNUH-12 and SNU-899) were studied. Cell cytotoxicity, the change of telomerase activity, and hTERT mRNA and hTR expression by 5-FU and cisplatin exposure were assessed by MTT assay, TRAP assay, and real-time RT-PCR, respectively. In two cell lines, after cisplatin exposure, the telomerase activity and hTERT mRNA expression decreased, but hTR expression in- creased according to the concentration of drug. However, in both cell lines, the telomerase activity and hTR did not show any significant change after 5-FU treatment, but the expression of hTERT mRNA decreased. These results suggest that there may be other important regulating mechanism except hTERT mRNA as the regulation factor of telomerase activity in HNSCC cell lines.

Keyword

Telomerase; Telomerase Reverse Transcriptase; Telomerase RNA, Cisplatin; 5-Fluorouracil

MeSH Terms

Antineoplastic Agents/pharmacology
Base Sequence
Carcinoma, Squamous Cell/*drug therapy/*enzymology/genetics
Cell Line, Tumor
Cisplatin/*pharmacology
DNA Primers/genetics
Fluorouracil/*pharmacology
Gene Expression/drug effects
Head and Neck Neoplasms/*drug therapy/*enzymology/genetics
Humans
RNA, Messenger/*genetics/*metabolism
RNA, Neoplasm/*genetics/*metabolism
Reverse Transcriptase Polymerase Chain Reaction
Telomerase/*genetics/*metabolism

Figure

• 

  Fig. 1 Cytotoxic effects of cisplatin (A) and 5-fluorouracil (5-FU) (B) in PNUH-12, SNU-899, and HEp-2. As the concentration of the cisplatin and 5-FU increased, the survival decreased.

• 

  Fig. 2 Photographs showing the telomerase activity of three head and neck cancer cell lines by cisplatin and 5-fluorouracil (5-FU) exposure. Telomerase activity was observed by telomerase assay in PNUH-12 (A) and SNU-899 (B) cell lines. The telomerase activity decreased in a concentration-dependent manner after cisplatin exposure, while the change in telomerase activity was insignificant after 5-FU exposure.

• 

  Fig. 3 Detection of hTERT mRNA in PNUH-12 (A) and SNU-899 (B) samples by real-time RT-PCR analysis using the LightCycler. Concomitant detection of PBGD mRNA served as a reference for relative quantification. The normalized hTERT mRNA levels decreased after cisplatin and 5-fluorouracil (5-FU) exposure in both cell lines.

• 

  Fig. 4 Detection of hTR in PNUH-12 (A) and SNU-899 (B) samples by real-time RT-PCR analysis using the LightCycler. Concomitant detection of PBGD mRNA served as a reference for relative quantification. In both cell lines, hTR levels were increased after cisplatin exposure, but, thy did not change significantly after 5-FU exposure.

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