Adenovirus-mediated interleukin-12 gene transfer combined with cytosine deaminase followed by 5-fluorocytosine treatment exerts potent antitumor activity in Renca tumor-bearing mice.

Abstract

BACKGROUND:

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.

METHODS:

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.

RESULTS:

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.

CONCLUSION:

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.

• Authors: Kyung-Sun Hwang, Won-Kyung Cho, Jinsang Yoo, Hwan-Jung Yun, Samyong Kim, Dong-Soo Im
• Journal: BMC cancer (BMC Cancer) Vol. 5 Pg. 51 (May 24 2005) ISSN: 1471-2407 [Electronic] England
• PMID: 15910693 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents
• DNA, Complementary
• Prodrugs
• Green Fluorescent Proteins
• Interleukin-12
• Interferon-gamma
• Cytosine Deaminase
• Fluorouracil

Topics

• Adenoviridae (genetics)
• Animals
• Antineoplastic Agents (pharmacology)
• Blotting, Western
• Carcinoma, Renal Cell (metabolism)
• Cell Line
• Cell Line, Tumor
• Cell Survival
• Cytosine Deaminase (pharmacology)
• DNA, Complementary (metabolism)
• Enzyme-Linked Immunosorbent Assay
• Escherichia coli (metabolism)
• Female
• Fluorouracil (pharmacology)
• Gene Transfer Techniques
• Genetic Therapy (methods)
• Genetic Vectors
• Green Fluorescent Proteins (metabolism)
• HeLa Cells
• Humans
• Interferon-gamma (metabolism)
• Interleukin-12 (genetics, metabolism)
• Kidney Neoplasms (metabolism)
• Killer Cells, Natural (metabolism)
• Male
• Mice
• Mice, Inbred BALB C
• Neoplasm Transplantation
• Neoplasms (genetics, therapy)
• Neoplasms, Experimental (genetics, therapy)
• Prodrugs (pharmacology)
• Spleen (metabolism)
• Time Factors
• Treatment Outcome