AAV2-mediated in vivo immune gene therapy of solid tumours

Adeno-associated virus type 2-mediated gene transfer of a short hairpin-RNA targeting human IGFBP-2 suppresses the proliferation and invasion of MDA-MB-468 cells

Adeno-associated virus 2 (AAV2) is prepotent in the biological treatment of breast tumor because of its low pathogenicity and immunogenicity. Our previous study demonstrated that insulin‑like growth factor‑binding protein 2 (IGFBP‑2) was highly expressed in patients with breast metastasis. In the present study, the effects of recombinant AAV2 on the growth and metastasis of breast cancer cells were determined in vitro, and in vivo. rAAV2-ZsGreen-shRNA-scramble and rAAV2‑ZsGreen‑shRNA‑hIGFBP‑2 were used to transfect MDA‑MB‑468, and MCF‑10A cells respectively, and observed that these virus could not penetrate the normal human breast epithelia MCF‑10A cell line. To investigate the effect of the recombinant virus on chemotherapeutics, paclitaxel was added to MDA‑MB‑468 cells and it was demonstrated that rAAV2‑ZsGreen‑shRNA‑hIGFBP-2-infected MDA-MB-468 cells were highly chemosensitive to paclitaxel compared with rAAV2‑ZsGreen‑shRNA‑scramble‑injected cells. In addition, it was demonstrated that the invasive ability of rAAV2‑ZsGreen‑shRNA‑hIGFBP‑2‑infected MDA-MB-468 cells was highly impaired compared with the rAAV2‑ZsGreen‑shRNA‑scramble group. In the nude mice xenografts, the rAAV2‑ZsGreen‑shRNA‑hIGFBP‑2 injection inhibited tumor growth and Ki‑67 expression was significantly downregulated compared with the scramble group. Following IGFBP‑2 knockdown using rAAV2-ZsGreen-shRNA-hIGFBP‑2, matrix metalloproteinase‑2 expression was significantly reduced in tumor tissues compared with that in rAAV2‑ZsGreen‑shRNA‑scramble treated tumor tissues. These findings have provided a direction for the application of novel AAV2‑based therapeutics for treating aggressive triple‑negative breast cancer types.

Targeting Atp6v1c1 Prevents Inflammation and Bone Erosion Caused by Periodontitis and Reveals Its Critical Function in Osteoimmunology

Periodontal disease (Periodontitis) is a serious disease that affects a majority of adult Americans and is associated with other systemic diseases, including diabetes, rheumatoid arthritis, and other inflammatory diseases. While great efforts have been devoted toward understanding the pathogenesis of periodontitis, there remains a pressing need for developing potent therapeutic strategies for targeting this pervasive and destructive disease. In this study, we utilized novel adeno-associated virus (AAV)-mediated Atp6v1c1 knockdown gene therapy to treat bone erosion and inflammatory caused by periodontitis in mouse model. Atp6v1c1 is a subunit of the V-ATPase complex and regulator of the assembly of the V0 and V1 domains of the V-ATPase complex. We demonstrated previously that Atp6v1c1 has an essential function in osteoclast mediated bone resorption. We hypothesized that Atp6v1c1 may be an ideal target to prevent the bone erosion and inflammation caused by periodontitis. To test the hypothesis, we employed AAV RNAi knockdown of Atp6v1c1 gene expression to prevent bone erosion and gingival inflammation simultaneously. We found that lesion-specific injection of AAV-shRNA-Atp6v1c1 into the periodontal disease lesions protected against bone erosion (>85%) and gingival inflammation caused by P. gingivalis W50 infection. AAV-mediated Atp6v1c1 knockdown dramatically reduced osteoclast numbers and inhibited the infiltration of dendritic cells and macrophages in the bacteria-induced inflammatory lesions in periodontitis. Silencing of Atp6v1c1 expression also prevented the expressions of osteoclast-related genes and pro-inflammatory cytokine genes. Our data suggests that AAV-shRNA-Atp6v1c1 treatment can significantly attenuate the bone erosion and inflammation caused by periodontitis, indicating the dual function of AAV-shRNA-Atp6v1c1 as an inhibitor of bone erosion mediated by osteoclasts, and as an inhibitor of inflammation through down-regulation of pro-inflammatory cytokine expression. This study demonstrated that Atp6v1c1 RNAi knockdown gene therapy mediated by AAV-shRNA-Atp6v1c1 is a promising novel therapeutic approach for the treatment of bone erosion and inflammatory related diseases, such as periodontitis and rheumatoid arthritis.

AAV2-mediated gene transfer of VEGF-Trap with potent suppression of primary breast tumor growth and spontaneous pulmonary metastases by long-term expression

Vascular endothelial growth factor (VEGF) is an important signaling protein and a predominant mediator of angiogenesis in tumor growth and metastasis. Therefore, antagonism of the VEGF pathway results in inhibition of abnormal angiogenesis, then suppression of tumor growth and metastasis. VEGF-Trap, a high-affinity soluble decoy receptor, is currently in phase II clinical trails, and has demonstrated more efficacy in different types of solid tumors by intravenous injection every two weeks. In our study, we used recombinant AAV2 as a delivery vehicle to achieve long-lasting expression of VEGF Trap protein in a mouse model for the first time. We report that AAV2-VEGF-Trap can be safely administered and sustained expression in vivo via a single intravenously administration, simultaneously suppressing primary tumor growth and preventing the pulmonary metastases of 4T1 tumors. Decreased microvessel density and increased tumor cell apoptosis were observed in the treatment group. AAV2-VEGF-Trap can obviously decrease not only the concentration of VEGF in sera, but also the concentration of other angiogenic factors, such as aFGF, bFGF, angiopoietin-1 and others. These studies suggest that AAV-mediated long-term expression of VEGF-Trap is a useful and safe tool to block tumor progression and inhibit spontaneous pulmonary metastases.