Inhibition of vascular endothelial growth factor by small interfering RNA upregulates differentiation, maturation and function of dendritic cells

Abstract

This study aimed to investigate the effects of vascular endothelial growth factor (VEGF) secreted by MCF-7 breast cancer cells on the differentiation, maturation and function of dendritic cells (DCs). Small interfering RNAs (siRNAs) directed against the VEGF gene were designed and transfected into MCF-7 breast cancer cells at an optimal concentration (100 nmol/l) using cationic liposome transfection reagent, whereas the control group was transfected with only transfection reagent. Western blot analysis and ELISA were used to determine VEGF protein expression and VEGF concentration, respectively. Mononuclear cells were cultured with the culture supernatants from primary MCF-7 cells (control group) and siRNA-treated MCF-7 cells (siRNA group). The DC phenotypes, including CD1a, CD80, CD83, CD86 and HLA-DR, were evaluated by flow cytometry. The MTT assay was used to assess the cytotoxicity of DC-mediated tumor-specific cytotoxic T lymphocytes (CTLs) against MCF-7 cells in the two different culture supernatants. The VEGF-targeted constructed siRNA inhibited VEGF expression in MCF-7 cells. Cultivation with the culture supernatants from MCF-7 cells treated with siRNA affected DC morphology. DCs in the siRNA group exhibited a significantly higher expression of CD86, CD80, CD83 and HLA-DR compared to the cells in the control group, whereas the expression of CD1a in the siRNA group was significantly lower compared to that in the control group. The cytotoxic activity of CTLs mediated by DCs was significantly altered by siRNA transfection. These results indicated that VEGF may play a significant role in tumor development, progression and immunosuppression.

Direct and indirect regulation of the tumor immune microenvironment by VEGF

“…Consistently, elevated DCs and reduced immature progenitor cells in peripheral blood have been detected in cancer patients after bevacizumab administration 80 . In vitro studies also suggest that supernatant from breast cancer cell lines with VEGF expression ablated by shRNA induces PBMC‐derived DCs to up‐regulate CD80, CD86, and HLA‐DR expression and enhances DC‐mediated T‐cell cytotoxicity 81 …”

Angiogenesis for tumor vascular normalization of Endostar on hepatoma 22 tumor-bearing mice is involved in the immune response

“…The results of the present study indicated that Endostar treatment was able to increase IFN-γ and CD86 levels and decrease the level of IL-17 in HCC mice. VEGF may serve an important role in tumor development, progression and immunosuppression associated with CD86 ( 58 ). Therefore, it was hypothesized that vascular normalization of Endostar may be associated with the suppression on Th17 response and regulation on Th1/Th2 imbalance.…”

Impact of Tumor-Derived Factors on Dendritic Cells in Cancer

“…Перспективным направлением является терапия с использованием препаратов -«ловушек» VEGF (афлиберцепт), направленная на ингибирование сигнального пути VEGF и повышение количества зрелых ДК у пациентов с рефрактерными солидными опухолями [29]. В свою очередь, исследования in vitro продемонстрировали, что ингибирование экспрессии VEGF с помощью коротких интерферирующих РНК в клетках рака молочной железы эффективно восстанавливает процесс дифференцировки и созревания ДК, что увеличивает способность ДК индуцировать опухолеспецифический цитотоксический Т-клеточный ответ [30].…”