Development of a Conditional Replication Competent Adenovirus, Controlled by the Human Telomerase Promoter (htert)

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1 Development of a Conditional Replication Competent Adenovirus, Controlled by the Human Telomerase Promoter (htert) Eunhee Kim, Joo-Hang Kim, M.D., Ha-Youn Shin, Han Saem Lee, Joo-Hyuk Sohn, M.D., Jai Myung Yang, Ph.D., Jungho Kim, Ph.D. and Chae-Ok Yun, Ph.D. Institute for Cancer Research, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul; Department of Life Science, Sogang University, Seoul, Korea Purpose: This study has been planned to generate a replication-competent adenovirus which replicates in a cancer cell-specific manner, thus minimizing the side effects and toxicity of cancer gene therapy. Materials and Methods: we have generated an EB 9 kd attenuated recombinant adenoviruses, Ad-TERT- 9 and Ad-mTERT- 9, which encode EA gene driven by the wild type htert and modified m-htert promoter containing additional c-myc and Sp binding sites in the backbone of Ad- EB9. The in vitro efficacy and specificity of the htert and m-htert promoter have been evaluated by the comparison of viral replication and cytopathic effect in cancer cells and normal cell lines. To assess anti-tumor effect and safety of htert or m-htert promoter driven replication competent adenoviruses, tumor regression after subcutaneous injection in subcutaneous C33A xenografts and lacz expression after systemic injection in organs were examined. Results: The activation of htert or m-htert promoter was significantly up-regulated only in htert-positive cells, but not in htert-negative cells. Moreover, the activity of m-htert promoter was substantially increased in htert-positive cancer cells, but not in htert-negative cells. While Ad-TERT- 9 replicated in and induced cytopathic effect in cancer and in some normal cell lines, Ad-mTERT- 9 enhanced viral replication and cytopathic effect in cancer cells only. Furthermore, the growth of established human cervical carcinoma in nude mice was significantly suppressed by intratumoral injection of Ad-mTERT- 9. Conclusions: The use of m-htert promoter is not only useful in the regulation of therapeutic gene expression but also that replication-competent oncolytic adenovirus under the control of m-htert promoter may be a new promising tool for the treatment of human malignancies. (Cancer Research and Treatment 3;35:9-6) Key Words: Cancer gene therapy, htert, Replication competent adenovirus

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4 A E3 ψ CMV lacz IX Ad left genome dl-cmv-z ψ htert lacz IX Ad left genome dl-tert- Z ψ htert Myc/Sp lacz IX Ad left genome dl-mtert-z B stop mutation E3 ψ EA EB9 EB55 Ad left genome Ad- EB9 ψ htert EA EB9 EB55 Ad left genome Ad-TERT- 9 ψ htert Myc/Sp EA EB9 EB55 Ad left genome Ad-mTERT- 9

5 Relative internal telomerase activity Hep3B A549 H46 C33A SK-Hep Cancer cell HepG MCF-7 U5-N HeLa 73WE IMR9 WI38 Normal cell BJ

6 dl-cmv-z dl-tert-z dl-mtert-z C33A U5N MCF7 73WE WI38

7 Relative lacz expression (OD 45 ) A. Cancer cells H A C33A MOI SK-Hep HepG Hep3B MOI U U5N MCF MOI B. Normal cells 73WE CBHEL MRC5 Relative lacz expression (OD 45 ) IMR WI BJ MOI MOI

8 Cancer Normal Cancer Normal Cancer Normal Anti-EA Anti-actin Ad- EB9 Ad-TERT- 9 Ad-mTERT- 9

9 A. Cancer cells MOI SK-Hep H46 C33A MOI U5N A549 HeLa B. Normal cells MOI WI38 BJ IMR9

10 Relative viability(%) A. Cancer cells Relative viability(%) SK-Hep H46 C33A U5N A549 HeLa days after infection B. Normal cells WI38 BJ IMR days after infection

11 Tumor size Viral injection Days after injection

12 Liver Heart Lung dl-cmv-z x x4 dl-tert-z x x4 dl-mtert-z x x4

13 Spleen Kidney Muscle dl-cmv-z x x4 dl-tert-z x x4 dl-mtert-z x x4

14 Stomach Testis Tumor x dl-cmv-z x4 dl-tert-z x x4 dl-mtert-z x x4

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