Objective： Oncolytic adenovirus, also called conditionally replicating adenovirus （CRAD）, has been developed for the treatment of cancer. However, there is a tremendous need to enhance their antitumor efficacy. Her...Objective： Oncolytic adenovirus, also called conditionally replicating adenovirus （CRAD）, has been developed for the treatment of cancer. However, there is a tremendous need to enhance their antitumor efficacy. Here we wish to evaluate whether a strategy that combines the herpes simplex virus-thymidine kinase with oncolytic effects offers a therapeutic advantage. Methods： A novel adenovirus Ad-ETK containing a sequentially positioned promoter of human telomerase reverse transcriptase （hTERT）, the coding sequence of E1A gene, an internal ribosome entry site sequence （IRES） and the coding sequence of herpes simplex virus-thymidine kinase （HSV-TK） was constructed. Infection of various cells with Ad-ETK followed by RT-PCR confirmed the expression of E1A and HSV-TK. The oncolytic ability and synergism between oncolytic effects and HSV-TK system was measured. The infection efficiency was determined by flow cytometry. Results： Ad-ETK deliverys E1A and HSV-TK gene, which selectively replicates in hTERT-positive tumor cells, and the progeny virus can reach up to 150 IU/cell. Our in vitro study showed that Ad-ETK plus ganciclovir （GCV） induced an obvious cell death. Conclusion： An oncolytic adenovirus plus the HSV-TK/GCV suicide gene system resulted in a significant improvement in treatment efficacy and it may offer important considerations in the development and preclinical assessments of oncolytic virotherapy.展开更多
More than two decades have passed since the first gene therapy clinical trial was conducted.During this time,we have gained much knowledge regarding gene therapy in general,but also learned to understand the fear that...More than two decades have passed since the first gene therapy clinical trial was conducted.During this time,we have gained much knowledge regarding gene therapy in general,but also learned to understand the fear that persists in society.We have experienced drawbacks and successes.More than 1700 clinical trials have been conducted where gene therapy is used as a means for therapy.In the very first trial,patients with advanced melanoma were treated with tumor infiltrating lymphocytes genetically modified ex-vivo to express tumor necrosis factor.Around the same time the first gene therapy trial was conducted,the ethical aspects of performing gene therapy on humans was intensively discussed.What are the risks involved with gene therapy?Can we control the technology?What is ethically acceptable and what are the indications gene therapy can be used for?Initially,gene therapy was thought to be implemented mainly for the treatment of monogenetic diseases,such as adenosine deaminase deficiency.However,other therapeutic areas have become of interest and currently cancer is the most studied therapeutic area for gene therapy based medicines.In this review I will be giving a short introduction into gene therapy and will direct the discussion to where we should go from here.Furthermore,I will focus on the use of the Herpes simplex virus-thymidine kinase for gene therapy of malignant gliomas and highlight the efficacy of gene therapy for the treatment of malignant gliomas,but other strategies will also be mentioned.展开更多
文摘Objective： Oncolytic adenovirus, also called conditionally replicating adenovirus （CRAD）, has been developed for the treatment of cancer. However, there is a tremendous need to enhance their antitumor efficacy. Here we wish to evaluate whether a strategy that combines the herpes simplex virus-thymidine kinase with oncolytic effects offers a therapeutic advantage. Methods： A novel adenovirus Ad-ETK containing a sequentially positioned promoter of human telomerase reverse transcriptase （hTERT）, the coding sequence of E1A gene, an internal ribosome entry site sequence （IRES） and the coding sequence of herpes simplex virus-thymidine kinase （HSV-TK） was constructed. Infection of various cells with Ad-ETK followed by RT-PCR confirmed the expression of E1A and HSV-TK. The oncolytic ability and synergism between oncolytic effects and HSV-TK system was measured. The infection efficiency was determined by flow cytometry. Results： Ad-ETK deliverys E1A and HSV-TK gene, which selectively replicates in hTERT-positive tumor cells, and the progeny virus can reach up to 150 IU/cell. Our in vitro study showed that Ad-ETK plus ganciclovir （GCV） induced an obvious cell death. Conclusion： An oncolytic adenovirus plus the HSV-TK/GCV suicide gene system resulted in a significant improvement in treatment efficacy and it may offer important considerations in the development and preclinical assessments of oncolytic virotherapy.
文摘More than two decades have passed since the first gene therapy clinical trial was conducted.During this time,we have gained much knowledge regarding gene therapy in general,but also learned to understand the fear that persists in society.We have experienced drawbacks and successes.More than 1700 clinical trials have been conducted where gene therapy is used as a means for therapy.In the very first trial,patients with advanced melanoma were treated with tumor infiltrating lymphocytes genetically modified ex-vivo to express tumor necrosis factor.Around the same time the first gene therapy trial was conducted,the ethical aspects of performing gene therapy on humans was intensively discussed.What are the risks involved with gene therapy?Can we control the technology?What is ethically acceptable and what are the indications gene therapy can be used for?Initially,gene therapy was thought to be implemented mainly for the treatment of monogenetic diseases,such as adenosine deaminase deficiency.However,other therapeutic areas have become of interest and currently cancer is the most studied therapeutic area for gene therapy based medicines.In this review I will be giving a short introduction into gene therapy and will direct the discussion to where we should go from here.Furthermore,I will focus on the use of the Herpes simplex virus-thymidine kinase for gene therapy of malignant gliomas and highlight the efficacy of gene therapy for the treatment of malignant gliomas,but other strategies will also be mentioned.
