Abstract
Regulatory T cells play a key role in suppressing tumor immunity. Triptolide,
a major active component isolated from the Chinese medicinal herb
Tripterygium wilfordii, has been proven to possess multiple
antitumor activities. Here, we investigated the effect of triptolide on
regulatory T cells and on the level of IL-10, transforming growth
factor-β, and vascular endothelial growth factor in tumor-bearing
mice. Fifty male C57BL/6 mice were randomly grouped as follows: normal
control group, model group with B16-F10 cells implanted, and three treatment
groups with cyclophosphamide, triptolide-high dose, triptolide-low dose. The
proportion of regulatory T cells in the spleen and axillary lymph nodes was
evaluated by flow cytometric analysis. Production of cytokines IL-10,
transforming growth factor-β, and vascular endothelial growth factor
in serum was measured using enzyme-labeled immunosorbent assay kits. The
mRNA levels of Foxp3, IL-10, and transforming growth factor-β in the
spleen and vascular endothelial growth factor in tumor tissue were detected
by real-time PCR. The results showed that triptolide significantly decreased
the proportion of regulatory T cells and lowered the Foxp3 level in the
spleen and axillary lymph nodes of tumor-bearing mice. Production of IL-10
and transforming growth factor-β in peripheral blood, and the mRNA
level of IL-10 and transforming growth factor-β in the spleen were
also decreased. Additionally, triptolide could remarkably inhibit production
of vascular endothelial growth factor in tumor-bearing mice. In conclusion,
our study demonstrated that triptolide might inhibit tumor growth by
inhibiting regulatory T cells and some cytokines such as IL-10 and
transforming growth factor-β, as well as production of vascular
endothelial growth factor.
Key words
triptolide - regulatory T cells - melanoma - cytokines -
Tripterygium wilfordii
- Celastraceae