Visualization of telomerase reverse transcriptase (hTERT) promoter activity using a trimodality fusion reporter...

Area of Science:

• Biomedical imaging
• Molecular biology
• Cancer research

Background:

• Chemotherapy efficacy relies on targeting critical tumor growth genes.
• Noninvasive monitoring of gene expression changes during treatment is crucial for assessing therapeutic response.
• Human telomerase reverse transcriptase (hTERT) is a key gene involved in tumor cell proliferation.

Purpose of the Study:

• To develop and validate a noninvasive method for measuring chemotherapy-induced changes in hTERT gene expression.
• To utilize radionuclide and optical imaging techniques for real-time monitoring of hTERT activity.
• To assess the utility of a multimodality reporter construct in studying gene expression in living subjects.

Main Methods:

• A fusion reporter construct including Renilla luciferase, monomeric red fluorescence protein 1, and truncated thymidine kinase was designed.
• The reporter construct was placed under the control of hTERT promoter fragments.
• Tumor cell lines were transfected, treated with 5-fluorouracil, and changes in reporter gene expression were imaged using bioluminescent, fluorescent, and radionuclide methods.

Main Results:

• The reporter construct demonstrated high expression in hTERT-expressing cell lines, allowing visualization of hTERT promoter activity.
• Cell lines lacking hTERT transcription showed minimal reporter expression.
• 5-fluorouracil treatment led to observable decreases in hTERT gene expression, visualized by fluorescent microscopy and bioluminescent imaging.

Conclusions:

• A single reporter construct can monitor hTERT promoter activity using both radionuclide and optical imaging systems.
• This multimodality reporter system provides a viable approach for studying critical tumor growth gene expression in vivo.
• The findings support the potential of this technique for noninvasive assessment of chemotherapy effects on tumor biology.