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Updated: May 25, 2026
An Efficient Method for Adenovirus Production
Published on: June 10, 2021
A simple detection system for adenovirus receptor expression using a telomerase-specific replication-competent
1Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
Abstract:
Adenovirus serotype 5 (Ad5) is frequently used as an effective vector for induction of therapeutic transgenes in cancer gene therapy or of tumor cell lysis in oncolytic virotherapy. Ad5 can infect target cells through binding with the coxsackie and adenovirus receptor (CAR). Thus, the infectious ability of Ad5-based vectors depends on the CAR expression level in target cells. There are conventional methods to evaluate the CAR expression level in human target cells, including flow cytometry, western blotting and immunohistochemistry. Here, we show a simple system for detection and assessment of functional CAR expression in human tumor cells, using the green fluorescent protein (GFP)-expressing telomerase-specific replication-competent adenovirus OBP-401. OBP-401 infection induced detectable GFP expression in CAR-expressing tumor cells, but not in CAR-negative tumor cells, nor in CAR-positive normal fibroblasts, 24 h after infection. OBP-401-mediated GFP expression was significantly associated with CAR expression in tumor cells. OBP-401 infection detected tumor cells with low CAR expression more efficiently than conventional methods. OBP-401 also distinguished CAR-positive tumor tissues from CAR-negative tumor and normal tissues in biopsy samples. These results suggest that GFP-expressing telomerase-specific replication-competent adenovirus is a very potent diagnostic tool for assessment of functional CAR expression in tumor cells for Ad5-based antitumor therapy.
Insights
A novel adenovirus vector (OBP-401) expressing GFP can detect functional coxsackie and adenovirus receptor (CAR) expression in human tumor cells. This tool efficiently assesses CAR levels for Ad5-based cancer therapies.
Area of Science:
- Oncolytic virotherapy
- Gene therapy
- Molecular diagnostics
Background:
- Adenovirus serotype 5 (Ad5) is a common vector in cancer gene therapy and oncolytic virotherapy.
- Ad5 infectivity relies on coxsackie and adenovirus receptor (CAR) expression levels on target cells.
- Current methods for assessing CAR expression (flow cytometry, western blotting, IHC) have limitations.
Purpose of the Study:
- To develop a simple and effective system for detecting and assessing functional CAR expression in human tumor cells.
- To evaluate the utility of a green fluorescent protein (GFP)-expressing, telomerase-specific, replication-competent adenovirus (OBP-401) for this purpose.
Main Methods:
- Infection of human tumor cells and normal fibroblasts with OBP-401.
- Assessment of GFP expression as an indicator of CAR-mediated infection.
- Comparison of OBP-401's detection efficiency with conventional methods.
- Evaluation of OBP-401 in distinguishing CAR-positive tumor tissues from normal and CAR-negative tissues in biopsy samples.
Main Results:
- OBP-401 infection resulted in detectable GFP expression specifically in CAR-expressing tumor cells.
- GFP expression correlated significantly with CAR levels in tumor cells.
- OBP-401 demonstrated higher efficiency in detecting low CAR expression compared to conventional methods.
- OBP-401 successfully differentiated CAR-positive tumor tissues from CAR-negative tissues in biopsy samples.
Conclusions:
- GFP-expressing, telomerase-specific, replication-competent adenovirus (OBP-401) is a potent diagnostic tool.
- OBP-401 enables accurate assessment of functional CAR expression in tumor cells.
- This method is valuable for optimizing Ad5-based antitumor therapies.
