Lentivirus-mediated small interfering RNA targeting VEGF-C inhibited tumor lymphangiogenesis and growth in breast carcinoma.

Lymph node metastasis is a major prognostic factor for patients with breast cancer. The activation of vascular endothelial growth factor (VEGF)-C plays a key role in lymph node metastasis through promoting lymphangiogenesis. Thus, we attempted to elucidate whether small interfering RNAs (siRNA) targeting VEGF-C could suppress lymphangiogenesis and lymph node metastasis in vivo. A lentivirus-based VEGF-C siRNA vector was infected into breast cancer cells and a xenograft model. The expression of VEGF-C mRNA and protein were quantified by quantitative real-time polymerase chain reaction (QRT-PCR), immunohistochemistry, and western blot analysis. The effect of VEGF-C siRNA on breast cancer cells was investigated by an invasion assay. Lymphangiogenesis was analyzed with anti-LYVE-1 and anti-D2-40 by immunohistochemical analysis. Lentivirus-mediated VEGF-C siRNA stably reduced VEGF-C mRNA and protein expression. VEGF-C siRNA inhibited the invasive ability of breast cancer cells in vitro. Five weeks after intratumoral injection, the tumor volume was significantly smaller in the VEGF-C siRNA group than in the control scramble siRNA group in the MDA-MB-231 cell xenograft model. The numbers of LYVE-1 and D2-40 positive vessels per microscopic field were significantly decreased in the VEGF-C siRNA group, which indicates that VEGF-C siRNA inhibited lymphangiogenesis. Moreover, lymph node metastasis was significantly suppressed by VEGF-C siRNA in vivo. In conclusion, these results indicate that lentivirus-mediated VEGF-C siRNA offers a new approach for therapeutic intervention to prevent tumor growth and lymphatic metastasis of breast cancer.

Guo B ，Zhang Y ，Luo G ，Li L ，Zhang J ... -  《-》

Vector-based RNA interference against vascular endothelial growth factor-C inhibits tumor lymphangiogenesis and growth of colorectal cancer in vivo in mice.

He XW ，Yu X ，Liu T ，Yu SY ，Chen DJ ... -  《CHINESE MEDICAL JOURNAL》

Down-regulation of vascular endothelial cell growth factor-C expression using small interfering RNA vectors in mammary tumors inhibits tumor lymphangiogenesis and spontaneous metastasis and enhances survival.

Chen Z ，Varney ML ，Backora MW ，Cowan K ，Solheim JC ，Talmadge JE ，Singh RK ... -  《CANCER RESEARCH》

Suppression of growth of pancreatic cancer cell and expression of vascular endothelial growth factor by gene silencing with RNA interference.

Wang J ，Shi YQ ，Yi J ，Ye S ，Wang LM ，Xu YP ，He M ，Kong XM ... -  《Journal of Digestive Diseases》

Combination therapy with short interfering RNA vectors against VEGF-C and VEGF-A suppresses lymph node and lung metastasis in a mouse immunocompetent mammary cancer model.

Cancer metastasis contributes significantly to cancer mortality and is facilitated by lymphangiogenesis and angiogenesis. Vascular endothelial growth factor-C (VEGF-C) and VEGF-A are involved in lymphangiogenesis and angiogenesis. To inhibit metastasis, combination therapy with vector-based small interfering RNA (siRNA) against VEGF-C and/or VEGF-A was conducted on murine metastatic mammary cancer. Syngeneic, inoculated, metastatic mammary cancers received direct intratumoral injection of plasmid siRNA vector targeting VEGF-C (psiRNA-VEGF-C), VEGF-A (psiRNA-VEGF-A), both VEGF-C and VEGF-A (both psiRNA-VEGF-C and psiRNA-VEGF-A vectors injected, referred to as the psiRNA-VEGF-C+A group) or a scrambled sequence (psiRNA-SCR) as control, once a week for 8 weeks. Gene electrotransfer was performed on the tumors after each injection. Tumor volume was significantly lower in the psiRNA-VEGF-A and the psiRNA-VEGF-C+A groups throughout the study. Lymph node metastasis was significantly less frequent in all therapeutic groups, whereas the multiplicity of lung metastases was significantly lower in the psiRNA-VEGF-C+A group only. All siRNA therapeutic groups showed a significant reduction in the number of dilated lymphatic vessels containing intraluminal cancer cells and microvessel density. Our data suggest that specific silencing of the VEGF-C or VEGF-A gene alone can inhibit lymph node metastasis. However, combination siRNA therapy targeting both VEGF-C and VEGF-A inhibits both lymph node and lung metastasis, rendering this combined therapy more beneficial than either alone. The observed anti-metastatic activity of siRNA-expressing vectors targeting VEGF-C or VEGF-A may be of high clinical significance in the treatment of metastatic breast cancer.

Shibata MA ，Morimoto J ，Shibata E ，Otsuki Y ... -  《-》