Lysis of dysplastic but not normal oral keratinocytes and tissue-engineered epithelia with conditionally replicating
Kamis Gaballah1, Allison Hills, David Curiel
1Head and Neck Cancer Unit, King's College London, Guy's, King's and St. Thomas' Hospitals, London, United Kingdom.
Abstract:
There is no effective medical treatment for oral precancer, and surgery to remove these lesions is imprecise because abnormal mucosa extends beyond the visible lesion. Development of vectors for tumor-selective viral replication has been a significant advance, and viral lysis is well suited to destruction of oral precancerous mucosa. To facilitate evaluation of new treatments, we engineered dysplastic oral epithelium using keratinocytes isolated from dysplastic lesions. We show that these model systems recapitulate the key characteristics of the clinical lesions closely, and that topical delivery of the conditionally replicating adenovirus (CRAd) dl922-947 can lyse tissue-engineered epithelia that show mild, moderate, or severe dysplasia, but normal oral epithelia are very resistant to this treatment. The lytic effect is determined by various factors, including the grade and proliferation index of the dysplastic epithelia. The presence of suprabasal cycling cells, expression of the coxsackie adenovirus receptor (CAR), the transcription cofactor p300, and other aberrations that affect the regulation of the cell cycle or apoptosis and promote viral replication may also be important. The ability of dl922-947 to destroy engineered oral dysplasia was significantly greater than that observed using wild-type adenovirus, d/1520, or viruses modified to bypass cell entry dependent on the presence of CAR. Evidence of infection in clinical dysplastic lesions was also shown ex vivo using tissue explants. We conclude that dl922-947 may provide an efficient molecular cytotoxic to dissolve oral dysplastic lesions.
Insights
A novel conditionally replicating adenovirus (CRAd) dl922-947 effectively destroys engineered oral dysplasia, offering a potential new treatment for oral precancer. Normal oral tissues show resistance, indicating targeted therapeutic potential.
Area of Science:
- Oncolytic Virology
- Oral Pathology
- Biotechnology
Background:
- Oral precancer lacks effective medical treatments, and surgical removal is often imprecise due to microscopic spread.
- Tumor-selective viral replication vectors represent a promising advance for targeted cancer therapy.
- Viral lysis is a suitable mechanism for destroying oral precancerous tissues.
Purpose of the Study:
- To engineer a reliable in vitro model of dysplastic oral epithelium for treatment evaluation.
- To assess the efficacy of a conditionally replicating adenovirus (CRAd) dl922-947 in lysing engineered oral dysplasia.
- To identify factors influencing the selective destruction of dysplastic oral epithelia by CRAd dl922-947.
Main Methods:
- Engineered dysplastic oral epithelium using keratinocytes from clinical lesions.
- Topically delivered CRAd dl922-947 to tissue-engineered epithelia with varying degrees of dysplasia.
- Assessed viral lysis and infection in normal and dysplastic oral epithelia.
- Compared the efficacy of dl922-947 with wild-type adenovirus and modified viruses.
- Evaluated viral infection in ex vivo clinical dysplastic oral tissue explants.
Main Results:
- Engineered oral epithelia models accurately recapitulated key features of clinical lesions.
- CRAd dl922-947 effectively lysed mild, moderate, and severe dysplastic oral epithelia.
- Normal oral epithelia demonstrated significant resistance to dl922-947-mediated lysis.
- Lytic effect correlated with dysplasia grade, proliferation index, suprabasal cycling cells, and coxsackie adenovirus receptor (CAR) expression.
- dl922-947 showed superior efficacy compared to wild-type adenovirus and CAR-independent viruses.
- Evidence of dl922-947 infection was observed in ex vivo clinical dysplastic lesions.
Conclusions:
- CRAd dl922-947 is an efficient molecular cytotoxic agent for targeting and dissolving oral dysplastic lesions.
- The engineered oral dysplasia model is valuable for evaluating novel oncolytic virotherapies.
- dl922-947 demonstrates tumor-selective replication and lysis, with potential for treating oral precancer.
