Imaging hNET reporter gene expression with 124I-MIBG

Area of Science:

• Molecular Biology
• Biotechnology
• Medical Imaging

Background:

• The norepinephrine transporter (NET) is a potential reporter gene.
• Previous efforts have explored NET for reporter gene applications.

Purpose of the Study:

• To construct and validate an internal ribosomal entry site (IRES)-linked human NET (hNET)-green fluorescent protein (GFP) hybrid reporter gene.
• To assess its utility for both nuclear and optical imaging applications.

Main Methods:

• A retroviral vector (pQCXhNET-IRES-GFP) was created to generate reporter cell lines and xenografts.
• Cells were sorted using fluorescence-activated cell sorting (FACS) based on GFP expression.
• In vitro and in vivo imaging studies were conducted using radiolabeled metaiodobenzylguanidine (MIBG).

Main Results:

• Transduced cells showed high accumulation of (123)I- or (124)I-MIBG compared to wild-type cells, primarily due to increased influx.
• A correlation was observed between radiotracer accumulation (K(1)) and GFP fluorescence intensity.
• (124)I-MIBG small-animal PET imaging of xenografts revealed advantages over (123)I-MIBG SPECT due to longer MIBG retention in transduced xenografts.

Conclusions:

• The hNET-IRES-GFP reporter system shows potential for broader application in reporter gene imaging.
• This technology could be translated to patient studies using existing SPECT and PET radiopharmaceuticals.