Zhang R, DeGroot L J
Department of Medicine, The University of Chicago, IL 60637, USA.
Clin Endocrinol (Oxf). 2000 Jun;52(6):687-94. doi: 10.1046/j.1365-2265.2000.01003.x.
Interleukin-12 (IL12) is a heterodimeric cytokine that plays an important role in the development of cellular immunity. Studies have demonstrated antitumour activity after systemic administration of recombinant IL12. As with other cytokines, with increasing dosage and longer exposure, systemic toxicity is observed. To reduce systemic toxicity and obtain local production of IL12, we developed a replication defective adenovirus transducing two subunits of the murine IL12 (AdCMVmIL12) gene.
Two separate cassettes, expressing the p35 or p40 subunit of mIL12, under the control of human cytomeglavirus immediate early promoter, were inserted into the early1 (E1) region of adenovirus 5. Biological activity of virally expressed mIL12 was demonstrated in vitro through its ability to induce proliferation of mouse ConA blast cells.
Rat medullary thyroid carcinoma (MTC) cells infected with AdCMVmIL12 lost their tumorigenicity in their syngenic WAG/Rij rat hosts. Efficient antitumour activity was found after direct injection of the AdCMVmIL12 vector into rMTC tumours. After intratumoural treatment with AdCMVmIL12, 86% of tumour bearing animals were apparently cured, and almost all remaining tumours were stabilized. Challenge studies showed that most animals cured after the first treatment remained tumour free after reinjection of wild type rMTC cells, indicating that long-term antitumour immunity developed.
This study demonstrates the construction of an adenoviral vector expressing a functional heterodimeric mIL12 and its efficient antitumour activity after in vivo delivery in an animal model of medullary thyroid carcinoma.
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。研究表明，全身给予重组IL12后具有抗肿瘤活性。与其他细胞因子一样，随着剂量增加和暴露时间延长，会观察到全身毒性。为了降低全身毒性并实现IL12的局部产生，我们构建了一种复制缺陷型腺病毒，其转导小鼠IL12的两个亚基（AdCMVmIL12）基因。
将两个分别在人巨细胞病毒立即早期启动子控制下表达mIL12的p35或p40亚基的独立盒式结构插入腺病毒5的早期1（E1）区域。通过其诱导小鼠伴刀豆球蛋白A母细胞增殖的能力在体外证明了病毒表达的mIL12的生物学活性。
感染AdCMVmIL12的大鼠甲状腺髓样癌（MTC）细胞在同基因的WAG/Rij大鼠宿主中失去了致瘤性。将AdCMVmIL12载体直接注射到rMTC肿瘤中后发现了有效的抗肿瘤活性。用AdCMVmIL12进行瘤内治疗后，86%的荷瘤动物明显治愈，几乎所有剩余肿瘤都得到了稳定。攻毒研究表明，大多数首次治疗后治愈的动物在重新注射野生型rMTC细胞后仍无肿瘤，表明产生了长期抗肿瘤免疫。
本研究证明了一种表达功能性异源二聚体mIL12的腺病毒载体的构建及其在甲状腺髓样癌动物模型体内递送后的有效抗肿瘤活性。
