No abstract

Thymoquinone (TQ), the predominant bioactive constituent derived from the medicinal spice Nigella sativa (also known as black cumin), has been applied for medical purposes for more than 2,000 years. Recent studies reported that thymoquinone exhibited inhibitory effects on the cell proliferation of several cancer cell lines. This study was performed to investigate the antitumor and anti-angiogenic effects of thymoquinone on osteosarcoma in vitro and in vivo. Our results showed that thymoquinone induced a higher percentage of growth inhibition and apoptosis in the human osteosarcoma cell line SaOS-2 compared to that of control, and thymoquinone significantly blocked human umbilical vein endothelial cell (HUVEC) tube formation in a dose-dependent manner. To investigate the possible mechanisms involved in these events, we performed electrophoretic mobility shift assay (EMSA) and western blot analysis, and found that thymoquinone significantly downregulated NF-κB DNA-binding activity, XIAP, survivin and VEGF in SaOS-2 cells. Moreover, the expression of cleaved caspase-3 and Smac were upregulated in SaOS-2 cells after treatment with thymoquinone. In addition to these in vitro results, we also found that thymoquinone inhibits tumor angiogenesis and tumor growth through suppressing NF-κB and its regulated molecules. Collectively, our results demonstrate that thymoquinone effectively inhibits tumor growth and angiogenesis both in vitro and in vivo. Moreover, inhibition of NF-κB and downstream effector molecules is a possible underlying mechanism of the antitumor and anti-angiogenic activity of thymoquinone in osteosarcoma.

The aryl hydrocarbon receptor (AhR) is an important immune regulator with a role in inflammatory response. However, the role of AhR in IL-10 production by inflammatory macrophages is currently unknown. In this study, we investigated LPS-induced IL-10 expression in macrophages from AhR-KO mice and AhR-overexpressing RAW264.7 cells. AhR was highly expressed after LPS stimulation through NF-κB pathway. Loss of AhR resulted in reduced IL-10 expression in LPS-induced macrophages. Moreover, the IL-10 expression was elevated in LPS-induced AhR-overexpressing RAW264.7 cells. Maximal IL-10 expression was dependent on an AhR non-genomic pathway closely related to Src and STAT3. Furthermore, AhR-associated Src activity was responsible for tyrosine phosphorylation of STAT3 and IL-10 expression by inflammatory macrophages. Adoptive transfer of AhR-expressing macrophages protected mice against LPS-induced peritonitis associated with high IL-10 production. In conclusion, we identified the AhR-Src-STAT3-IL-10 signaling pathway as a critical pathway in the immune regulation of inflammatory macrophages, It suggests that AhR may be a potential therapeutic target in immune response.

No abstract

Bone marrow stromal cells (BMSCs) have been well established as an ideal source of cell-based therapy for bone tissue engineering applications. Boron (B) is a notable trace element in humans; so far, the effects of boron on the osteogenic differentiation of BMSCs have not been reported. The aim of this study was to evaluate the effects of boron (0, 1, 10,100, and 1,000 ng/ml) on osteogenic differentiation of human BMSCs. In this study, BMSCs proliferation was analyzed by cell counting kit-8 (CCK8) assay, and cell osteogenic differentiation was evaluated by alkaline phosphatase (ALP) activity assay, Von Kossa staining, and real-time PCR. The results indicated that the proliferation of BMSCs was no different from the control group when added with B at the concentration of 1, 10, and 100 ng/ml respectively (P > 0.05); in contrast, 1,000 ng/ml B inhibited the proliferation of BMSCs at days 4, 7, and 14 (P < 0.05). By ALP staining, we discovered that BMSCs treated with 10 and 100 ng/ml B presented a higher ALP activity compared with control (P < 0.05). By real-time PCR, we detected the messenger RNA expression of ALP, osteocalcin, collagen type I, and bone morphogenetic proteins 7 were also increased in 10 and 100 ng/ml B treatment groups (P < 0.05). The calcium depositions were increased in 1 and 10 ng/ml B treatment groups (P < 0.05). Taken all together, it was the first time to report that B could increase osteogenic effect by stimulating osteogenic differentiation-related marker gene synthesis during the proliferation and differentiation phase in human BMSCs and could be a promising approach for enhancing osteogenic capacity of cell-based construction in bone tissue engineering.