BZLF1-armed oncolytic adenovirus for targeted therapy of EBV-associated gastric carcinoma : 엡스타인-바 바이러스 관련 위암 표적 치료를 위한 BZLF1 기반 종양용해 아데노바이러스

다국어 초록 (Multilingual Abstract)

Oncolytic adenoviruses represent a promising therapeutic strategy by selectively targeting tumor cells and inducing potent antitumor effects. In this study, we engineered a novel oncolytic adenovirus, designated Ad-TBZ, specifically designed to target Epstein-Barr virus-associated gastric carcinoma (EBVaGC). Ad-TBZ was constructed to harbor an E1A-IRES-E1B cassette under the control of the human telomerase promoter (hTERTp), together with BZLF1 expressed under the cytomegalovirus promoter (CMVp). EBVaGC accounts for approximately 10% of all gastric cancers worldwide, with more than 80,000 new cases annually, and is characterized by the presence of latent EBV infection in tumor cells.
Ad-TBZ demonstrated selective replication and significant cytotoxicity in EBVaGC cell lines, including SNU719, YCCEL1, NCC24, AGS-EBV, and MKN1-EBV. In particular, SNU719 and MKN1-EBV cells exhibited up to 99% cytopathic effect (CPE) at multiplicities of infection (MOIs) ranging from 15 to 300. By contrast, no cytotoxicity was observed in EBV-negative gastric cancer cells (AGS), while AGS-EBV cells showed dose-dependent cytotoxicity. Furthermore, in normal fibroblasts (CCD-986sk), Ad-TBZ infection did not induce BZLF1 protein expression or cytotoxicity, confirming its tumor-specific selectivity. Annexin V & Dead Cell assay revealed that Ad-TBZ induced late apoptosis at levels ranging from 10% to 80%. In xenograft mouse models (MKN1-EBV and SNU719), Ad-TBZ significantly suppressed tumor growth, accompanied by increased expression of BZLF1 and E1A proteins confirmed by immunohistochemistry. Moreover, combinatorial treatment with platinum-based chemotherapy showed potential synergistic effects under specific in vitro conditions and yielded significant antitumor efficacy in vivo.
Collectively, these findings demonstrate that Ad-TBZ is a safe and effective therapeutic platform with high tumor specificity and potent antitumor activity against EBVaGC. This study provides a foundation for the development of Ad-TBZ as a novel therapeutic option for EBVaGC and highlights its potential applicability to EBV-associated malignancies.

목차 (Table of Contents)

• I. INTRODUCTION 1
• 1. Anti-cancer drug 1
• 2. Oncolytic adenoviruses (OAds) 2
• 3. Epstein-Barr virus associated gastric carcinoma (EBVaGC) 3
• 4. Ad-TBZ (BZLF1-expressing oncolytic adenovirus) 4
• 5. Purpose of study 6
• II. MATERIALS AND METHODS 7
• 1. Cell cultures and reagents 7
• 2. Recombinant adenovirus construction 7
• 3. Western blotting 9
• 4. Cell viability assay 10
• 5. Apoptosis assay 11
• 6. Cytopathic effect (CPE) assay of oncolytic adenovirus in EBVaGC 12
• 7. Animals 12
• 8. Animal study #1: Ad-TBZ in the MKN1-EBV xenograft model 13
• 9. Animal study #2: Ad-TBZ in the SNU719 xenograft model 13
• 10. Animal study #3: Synergy of Ad-TBZ and oxaliplatin in the SNU719 model 14
• 11. Immunohistochemistry (IHC) 14
• 12. Statistical analysis 15
• III. RESULTS 16
• 1. Construction and functional characterization of Ad-TBZ 16
• 2. Selective cytotoxicity of Ad-TBZ in EBVaGC vs. normal cells 19
• 3. Tumor-specific effects of Ad-TBZ and BZLF1-mediated cytopathic effects 22
• 4. Antitumor effects of Ad-TBZ in the MKN1-EBV xenograft model 25
• 5. Antitumor effects of Ad-TBZ in the SNU719 xenograft model 27
• 6. In vitro synergistic effects of Ad-TBZ and oxaliplatin in gastric cancer cells 31
• 7. Synergistic effects of Ad-TBZ and oxaliplatin in the SNU719 xenograft model 34
• IV. DISCUSSION 38
• V. REFERENCES 42
• VI. ABSTRACT 48
• 국문 초록 50