Hwang Kyung-Sun, Cho Won-Kyung, Yoo Jinsang, Yun Hwan-Jung, Kim Samyong, Im Dong-Soo
Laboratory of Gene Therapy and Virology, Korea Research Institute of Bioscience and Biotechnology, Yusong, Daejeon, Republic of Korea.
BMC Cancer. 2005 May 24;5:51. doi: 10.1186/1471-2407-5-51.
Therapeutic gene transfer affords a clinically feasible and safe approach to cancer treatment but a more effective modality is needed to improve clinical outcomes. Combined transfer of therapeutic genes with different modes of actions may be a means to this end. Interleukin-12 (IL-12), a heterodimeric immunoregulatory cytokine composed of covalently linked p35 and p40 subunits, has antitumor activity in animal models. The enzyme/prodrug strategy using cytosine deaminase (CD) and 5-fluorocytosine (5-FC) has been used for cancer gene therapy. We have evaluated the antitumor effect of combining IL-12 with CD gene transfer in mice bearing renal cell carcinoma (Renca) tumors.
Adenoviral vectors were constructed encoding one or both subunits of murine IL-12 (Ad.p35, Ad.p40 and Ad.IL-12) or cytosine deaminase (Ad.CD). The functionality of the IL-12 or CD gene products expressed from these vectors was validated by splenic interferon (IFN)-gamma production or viability assays in cultured cells. Ad.p35 plus Ad.p40, or Ad.IL-12, with or without Ad.CD, were administered (single-dose) intratumorally to Renca tumor-bearing mice. The animals injected with Ad.CD also received 5-FC intraperitoneally. The antitumor effects were then evaluated by measuring tumor regression, mean animal survival time, splenic natural killer (NK) cell activity and IFN-gamma production.
The inhibition of tumor growth in mice treated with Ad.p35 plus Ad.p40 and Ad.CD, followed by injection of 5-FC, was significantly greater than that in mice treated with Ad.CD/5-FC, a mixture of Ad.p35 plus Ad.p40, or Ad.GFP (control). The combined gene transfer increased splenic NK cell activity and IFN-gamma production by splenocytes. Ad.CD/5-FC treatment significantly increased the antitumor effect of Ad.IL-12 in terms of tumor growth inhibition and mean animal survival time.
The results suggest that adenovirus-mediated IL-12 gene transfer combined with Ad.CD followed by 5-FC treatment may be useful for treating cancers.
治疗性基因转移为癌症治疗提供了一种临床可行且安全的方法，但需要更有效的方式来改善临床疗效。联合转移具有不同作用方式的治疗性基因可能是实现这一目标的一种手段。白细胞介素-12（IL-12）是一种由共价连接的p35和p40亚基组成的异二聚体免疫调节细胞因子，在动物模型中具有抗肿瘤活性。使用胞嘧啶脱氨酶（CD）和5-氟胞嘧啶（5-FC）的酶/前药策略已用于癌症基因治疗。我们评估了在携带肾细胞癌（Renca）肿瘤的小鼠中联合IL-12与CD基因转移的抗肿瘤效果。
构建编码小鼠IL-12的一个或两个亚基（Ad.p35、Ad.p40和Ad.IL-12）或胞嘧啶脱氨酶（Ad.CD）的腺病毒载体。通过培养细胞中脾细胞干扰素（IFN）-γ产生或活力测定来验证从这些载体表达的IL-12或CD基因产物的功能。将Ad.p35加Ad.p40或Ad.IL-12，联合或不联合Ad.CD，瘤内注射（单剂量）给携带Renca肿瘤的小鼠。注射Ad.CD的动物还腹腔注射5-FC。然后通过测量肿瘤消退、动物平均生存时间、脾自然杀伤（NK）细胞活性和IFN-γ产生来评估抗肿瘤效果。
用Ad.p35加Ad.p40和Ad.CD治疗，随后注射5-FC的小鼠中肿瘤生长的抑制明显大于用Ad.CD/5-FC、Ad.p35加Ad.p40的混合物或Ad.GFP（对照）治疗的小鼠。联合基因转移增加了脾NK细胞活性和脾细胞IFN-γ产生。就肿瘤生长抑制和动物平均生存时间而言，Ad.CD/5-FC治疗显著增加了Ad.IL-12的抗肿瘤效果。
结果表明，腺病毒介导的IL-12基因转移联合Ad.CD随后进行5-FC治疗可能对癌症治疗有用。
