Adeno-associated Viral Vector Mediated Systemic Anti-angiogenic Gene Therapy For Murine Lymphoma

Since tumor growth and metastasis depends on the generation of new blood vessels, anti-angiogenic therapy was proposed to be effective for the treatment of a variety of malignancies. To examine the feasibility of adeno-associated viral (AAV) vector mediated systemic anti-angiogenic gene therapy for lymphoma, we transduced C2C12 with the AAV expressing endostatin and got the high transduction efficency and the high endostatin expression.we established a lymphoma murine model in which the lymphoma cell line A20 expressing luciferase gene was inoculated into the caudal vein of BALB/C. Using this lymphoma murine model, we can detect the tumor growth and metastasis by a real-time in vivo imaging analyze system (IVIS) which make the tumor growth monitoring noninvasive and exact.Intramuscular infusion of 14×10⁹ vg /mouse and 1×10¹⁰vg /mouse CAGS-AAV-endostatin pseudotyped with serotype 8 capsid,in 6 lymphoma mice respectively,resulted in therapeutic serum endostatin expression of endostatin at levels that were comparable to those achieved after delivery of 1×10¹⁰vg /mouse GFP expressing AAV intramuscularly, 2.3(48.9±7.5 vs. 21.3±3.3 ng/ml; p<0.001) times and 2.6times(55.5±7.2 vs. 21.3±3.3ng/ml; p<0.001) respectively in the first week,4.4 times(95.6±4.1 vs. 21.7±3.3ng/ml; p<0.001) and 4.3 times(94.2±8.2 vs. 21.3±3.3ng/ml; p0.001) in the second week.Four weeks after IM, the serum endostatin concentration was detected to be significantly higher in the1×10¹⁰ vg/mouse group than the 1×10⁹ vg/mouse group (105.3±9.6 vs. 78.8±5.3ng/ml; p<0.001).Suppression of tumor growth was observed in ssAAVtype8 expressing mEnd injected mice 1×10⁹vg/mouse and 1×10¹⁰vg/mouse group compared to control in the first week respectively (1.3×10⁷±7.1×10⁶ vs. 1.3×10⁸±2.5×10⁷ photons/sec; p<0.003), (1.6×10⁷±1.8×10⁷ vs. 1.3×10⁸±2.5×0⁷photons/sec; p<0.003) and the second week (3.7×10⁷±3.1×10⁷ vs. 2.2×10⁸±5.9×10⁷photons/sec; p<0.01), (2.3×10⁷±2.7×10⁷ vs. 2.2×10⁸±5.9×10⁷ photons/sec; p<0.01). Survival effect was also detected in ssAAV2/8 injected mice(1×10¹⁰ vg/mouse group>1×10⁹ vg/mouse group>control). These results demonstrated that ssAAVtype8 mediated systemic expression of endostatin is useful for the gene therapy of lymphoma with low dose administration .