Icaritin ameliorates extracellular microparticles-induced inflammatory pre-metastatic niche via modulating the cGAS-STING signaling.

The concept of the inflammatory pre-metastatic niche (PMN) provides a new and promising direction for the prevention and treatment of metastasis. The excessive activation of the GAS-STING signaling leads to augmented metastasis by promoting the formation of the inflammatory PMN. In this study, tumor-derived microparticles (MP) were used to establish the PMN model both in vitro and in vivo, and pro-inflammatory mediators were also employed to evaluate the effects of Icaritin (ICT). It was demonstrated that ICT could inhibit the pulmonary metastasis of B16BL6 melanoma cells in mice via interfering with PMN. The phosphorylation and dimerization of STING and its downstream signaling TBK1-IFNß were proved to be diminished in the presence of ICT. Furthermore, we revealed that ICT suppressed the generation of pro-inflammatory PMN through conferring the inactivation of the STING signaling pathway. CETSA and DARTS assay also confirmed that STING tended to be a target for the action of ICT. Collectively, our findings highlight a new binding mechanism between STING and ICT for the inhibition of transduction of the STING signaling pathway, suggesting that pharmacological or therapeutic intervention of the STING-TBK1-IFNß singling axis may serve as an effective strategy to prevent the progression of inflammatory PMN and lung metastasis.

Extracellular Microparticles Encapsulated with Diallyl Trisulfide Interfere with the Inflammatory Tumor Microenvironment and Lung Metastasis of Invasive Melanoma.

Lung metastasis is a fatal and late-stage event for many solid tumors. Multiple lines of evidence have demonstrated that diallyl trisulfide (DATS), an active ingredient of garlic, possesses striking antimetastatic effects. However, the lack of highly efficient organ-compatible carriers restricts its application. In the present study, we showed that extracellular microparticles encapsulated with DATS (DATS-MPs) were capable of interfering with the prometastatic inflammatory microenvironment in local tissues. DATS-MPs were successfully prepared and exhibited typical characteristics of B16BL6-derived extracellular vesicles. The DATS-MPs preferentially fused with cancer cells and endogenous cells (mouse lung epithelial MLE-12 cells) from the metastatic organs in vitro. More interestingly, the systemically administered MPs predominantly accumulated in the lung tissue that serves as their main metastatic organ. The drug-loaded MPs exerted higher antimetastatic effects than DATS alone in both the spontaneous and the experimental metastasis models in mice (*p < 0.05). Additionally, we found that DATS-MPs inhibited tumor cell migration and interfered with the prometastatic inflammatory microenvironment via decreasing the release of S100A8/A9, serum amyloid A (SAA), and interleukin-6 (IL-6) and inhibiting the expression of fibronectin, MRP8, myeloperoxidase (MPO), and the toll-like receptor 4 (TLR4)-Myd88 in the lung tissues. Collectively, DATS-MPs appeared to enhance the antimetastatic efficiency of DATS in animal models under study.

Experimental study of the anti-tumour activity and pharmacokinetics of arctigenin and its valine ester derivative.

Arctigenin (ARG) is a functional active component that has important physiological and pharmacological activities. The anti-tumour and anti-inflammatory activities of ARG show good potential for application and development, but this material has the defect of low water solubility. In this experiment, the valine derivative of ARG (ARG-V) was designed and synthesized to overcome this disadvantage. The ARG amino acid, EDCI and DMAP were raw materials in the addition reaction, with a molar ratio of 1:2:2:0.5. The yield of ARG-V was up to 80%. ARG-V has strong anti-tumour activity in vivo and in vitro. The inhibitory rate of ARG-V was 69.2%, with less damage to the immune organs and different degrees of increased serum cytotoxicity. Moreover, the pharmacokinetics of ARG following oral administration and ARG-V following oral administration in rats were also studied. The Cmax and AUC values of ARG-V showed significant differences compared to ARG. The relative bioavailabilities of three doses of ARG-V compared to ARG were 664.7%, 741.5% and 812.9%. These pharmacokinetic results may be useful for further studies of the bioactive mechanism of ARG and provide a theoretical basic for clinical use.