Zhang Rusheng, DeGroot Leslie J
Thyroid Study Unit, Department of Medicine, The University of Chicago, Chicago, Illinois 60637, USA.
Endocrinology. 2003 Apr;144(4):1393-8. doi: 10.1210/en.2002-221013.
Interleukin-12 (IL12) is a heterodimeric cytokine that plays an important role in the development of cellular immunity. We previously reported the antitumor activity of mouse IL12 (mIL12) transduced by adenovirus in a medullary thyroid carcinoma model. In this study, a rat thyroid follicular cancer cell line (RTC-R2) was employed to develop tumors after sc injection in Wistar rats. In five of five animals, RTC-R2 cells infected with mIL12 transducing adenovirus (AdCMVmIL12) in vitro failed to be tumorigenic in vivo in syngenic rats, whereas four of five animals developed tumors after injection of luciferase transducing adenovirus (AdCMVLuc)-infected cells. After intratumoral treatment with AdCMVmIL12 at 1 x 10(9) plaque-forming units per rat, 90% (26/29) of animals bearing small (<100 mm(3)) tumors were apparently cured. Larger tumors treated by injection of AdCMVmIL12 became significantly smaller than AdCMVLuc-treated animals, and growth stabilized. Challenge studies showed that only 3 of 28 animals previously treated and cured with AdCMVmIL12 developed a tumor after sc reinjection of RTC-R2 cells, whereas all animals developed tumors in naïve animals. Thus, AdCMVmIL12-treated animals developed long-term antitumor immunity. We also studied animals with two tumors, injecting virus in one. Tumors regressed at both sites in five of six animals after treatment of one tumor with AdCMVmIL12, and in the sixth animal one site tumor regressed and another tumor continued to grow. In AdCMVLuc-treated animals, both tumors regressed in only one animal, and the reminder continued to grow. To detect toxicity to liver and other tissues after administration of AdCMVmIL2, the vector was administrated intratumorally or iv at the dose of 2 x 10(9) plaque-forming units per rat. No change in behavior was observed in any of the treated animals. Rats were killed at different time after virus administration. An overt increase of spleen size was observed 7 d after infection in all animals treated with AdCMVmIL12. All animals given virus IV had some lymphocyte infiltration in the sinusoids and triads of the liver, whereas AdCMVmIL12 injected intratumorally did not cause this effect. Spleens of some virus-treated animals showed decreased white pulp, with apparently increased hematopoiesis. No specific changes were found in lungs and kidneys. Iv administration of AdCMVmIL12 induced a moderate increase of glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase, whereas AdCMVmIL12 injected intratumorally did not. This study confirms the efficient antitumor activity of an adenovirus expressing mIL12 after in vivo delivery in an animal model and indicates the possibility of application to patients because of the low toxicity.
白细胞介素-12（IL12）是一种异源二聚体细胞因子，在细胞免疫的发展中起重要作用。我们之前报道了腺病毒转导的小鼠IL12（mIL12）在甲状腺髓样癌模型中的抗肿瘤活性。在本研究中，使用大鼠甲状腺滤泡癌细胞系（RTC-R2），经皮下注射到Wistar大鼠体内以形成肿瘤。在五只动物中的五只里，体外感染mIL12转导腺病毒（AdCMVmIL12）的RTC-R2细胞在同基因大鼠体内未能致瘤，而五只动物中的四只在注射荧光素酶转导腺病毒（AdCMVLuc）感染的细胞后形成了肿瘤。每只大鼠瘤内注射1×10⁹ 噬斑形成单位的AdCMVmIL12后，90%（26/29）携带小肿瘤（<100 mm³）的动物明显治愈。注射AdCMVmIL12治疗的较大肿瘤明显比AdCMVLuc治疗的动物的肿瘤更小，且生长稳定。攻毒研究表明，之前用AdCMVmIL12治疗并治愈的28只动物中，只有3只在皮下再次注射RTC-R2细胞后形成了肿瘤，而所有未处理的动物都形成了肿瘤。因此，经AdCMVmIL12治疗的动物产生了长期抗肿瘤免疫力。我们还研究了有两个肿瘤的动物，在其中一个肿瘤中注射病毒。用AdCMVmIL12治疗一个肿瘤后，六只动物中的五只两个部位的肿瘤都消退了，第六只动物一个部位的肿瘤消退而另一个肿瘤继续生长。在AdCMVLuc治疗的动物中，只有一只动物的两个肿瘤都消退了，其余的继续生长。为检测给予AdCMVmIL2后对肝脏和其他组织的毒性，以每只大鼠2×10⁹ 噬斑形成单位的剂量瘤内或静脉注射该载体。在任何一只处理过的动物中均未观察到行为改变。病毒给药后在不同时间处死大鼠。在所有用AdCMVmIL12治疗的动物中，感染后7天观察到脾脏大小明显增加。所有静脉注射病毒的动物在肝脏的血窦和汇管区有一些淋巴细胞浸润，而瘤内注射AdCMVmIL12未引起这种效应。一些病毒处理动物的脾脏白髓减少，造血明显增加。在肺和肾中未发现特异性变化。静脉注射AdCMVmIL12导致谷草转氨酶和谷丙转氨酶适度升高，而瘤内注射AdCMVmIL12则未出现这种情况。本研究证实了在动物模型中体内递送后表达mIL12的腺病毒具有有效的抗肿瘤活性，并表明由于毒性低而有可能应用于患者。
