Shashkova Elena V, Doronin Konstantin, Senac Julien S, Barry Michael A
Division of Infectious Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota, USA.
Cancer Res. 2008 Jul 15;68(14):5896-904. doi: 10.1158/0008-5472.CAN-08-0488.
Liver tropism of systemically delivered adenoviruses (Ad) represents a considerable challenge for their use as anticancer therapeutics. More than 90% of i.v. injected Ad is rapidly taken up by the liver leading to hepatotoxicity, reduced virus uptake by target tumor tissue, and diminished therapeutic efficacy. The lack of clinical activity of systemically given oncolytic Ad demands for better understanding and improvement of virus pharmacokinetics. We studied the effects of Ad "detargeting" from liver macrophages (Kupffer cells) and hepatocytes on toxicity and anticancer efficacy using a nonattenuated oncolytic Ad expressing enhanced green fluorescent protein-firefly luciferase fusion protein (Ad-EGFPLuc). Kupffer cell depletion before i.v. injection of Ad-EGFPLuc increased transgene expression in the liver 40.7-fold on day 3 after the injection indicating compensatory enhancement of hepatocyte transduction due to increased bioavailability of the virus. Pretreatment of mice with the anticoagulant drug warfarin to block blood factor-dependent binding of the virus to hepatocytes markedly reduced luciferase expression in the liver and mediated the corresponding decrease of hepatotoxicity in mice with intact and depleted liver macrophages. Combined depletion of Kupffer cells and pretreatment with warfarin before a single i.v. injection of Ad-EGFPLuc significantly reduced tumor growth and prolonged survival of nude mice bearing subcutaneous xenografts of aggressive human hepatocellular carcinoma. The improved antitumor activity correlated with enhanced transgene expression and virus spread in the tumors. These data suggest that detargeting oncolytic Ad from liver macrophages and hepatocytes is an effective strategy to increase the therapeutic window for therapy against disseminated tumor sites.
全身给药的腺病毒（Ad）对肝脏的趋向性是其作为抗癌治疗药物应用的一个重大挑战。静脉注射的Ad超过90%会迅速被肝脏摄取，导致肝毒性、靶肿瘤组织对病毒的摄取减少以及治疗效果降低。全身给予溶瘤Ad缺乏临床活性，这需要更好地理解和改善病毒药代动力学。我们使用表达增强型绿色荧光蛋白-萤火虫荧光素酶融合蛋白的非减毒溶瘤Ad（Ad-EGFPLuc），研究了Ad从肝巨噬细胞（库普弗细胞）和肝细胞“脱靶”对毒性和抗癌疗效的影响。静脉注射Ad-EGFPLuc前清除库普弗细胞，在注射后第3天肝脏中的转基因表达增加了40.7倍，这表明由于病毒生物利用度增加，肝细胞转导得到了代偿性增强。用抗凝药物华法林预处理小鼠以阻断病毒与肝细胞的血液因子依赖性结合，显著降低了肝脏中的荧光素酶表达，并介导了肝巨噬细胞完整和清除的小鼠肝毒性的相应降低。在单次静脉注射Ad-EGFPLuc前联合清除库普弗细胞和用华法林预处理，显著降低了携带侵袭性人肝细胞癌皮下异种移植物的裸鼠的肿瘤生长并延长了其生存期。改善的抗肿瘤活性与肿瘤中转基因表达增强和病毒传播相关。这些数据表明，使溶瘤Ad从肝巨噬细胞和肝细胞脱靶是增加针对播散性肿瘤部位治疗的治疗窗的有效策略。
