Suppressive role of diallyl trisulfide in the activated platelet-mediated hematogenous metastasis of MDA-MB-231 human breast cancer cells.

Accumulating evidence has indicated that garlic consumption may reduce the risk of developing several types of cancer, and extensive studies have revealed the effects of its bioactive component, diallyl trisulfide (DATS), on the proliferation and apoptosis of tumor cells. The present study was undertaken to examine whether DATS affects hematogenous metastasis. In view of the dynamic crosstalk interplayed by tumor cells and platelets in hematogenous metastasis, we attempted to demonstrate the role of DATS in the metastatic behavior of MDA-MB-231 human breast cancer cells, which were co-incubated with activated platelets. Indeed, our data indicated that DATS significantly blocked platelet activation and aggregation induced by platelet-activating factor (PAF), and decreased the production of thromboxane B2 (TXB2). It was also found that DATS suppressed the migration and invasion of MDA-MB-231 cells in the presence of platelets activated by PAF in vitro in a dose-dependent manner. Furthermore, our results revealed thaat the release of activated TGF-ß1 in the platelet-tumor cell system was markedly attenuated by DATS. Therefore, our findings strongly suggest that the diverse pharmacological activities of DATS are at least partially reflected by the interruption of the activated platelets-mediated metastasis of breast cancer cells.

Xanthatin anti-tumor cytotoxicity is mediated via glycogen synthase kinase-3ß and ß-catenin.

Xanthatin, a xanthanolide sesquiterpene lactone isolated from Xanthium strumarium L. (Asteraceae), has prominent anti-tumor activity. Initial mechanism of action studies suggested xanthatin triggered activation of Wnt/ß-catenin. We examined the effects of xanthatin on signaling pathways in A459 lung cancer cells and mouse embryonic fibroblasts to ascertain requirements for xanthatin-induced cell death and tumor growth in xenografts. Genetic inactivation of GSK-3ß, but not the related isoform GSK-3α, compromised xanthatin cytotoxicity while inactivation of ß-catenin enhanced xanthatin-mediated cell death. These data provide insight into how xanthatin and related molecules could be effectively targeted toward certain tumors.

Antimetastatic Therapies of the Polysulfide Diallyl Trisulfide against Triple-Negative Breast Cancer (TNBC) via Suppressing MMP2/9 by Blocking NF-κB and ERK/MAPK Signaling Pathways.

BACKGROUND: Migration and invasion are two crucial steps of tumor metastasis. Blockage of these steps may be an effective strategy to reduce the risk. The objective of the present study was to investigate the effects of diallyl trisulfide (DATS), a natural organosulfuric compound with most sulfur atoms found in garlic, on migration and invasion in triple negative breast cancer (TNBC) cells. Molecular mechanisms underlying the anticancer effects of DATS were further investigated. METHODS AND RESULTS: MDA-MB-231 cells and HS 578t breast cancer cells were treated with different concentrations of DATS. DATS obviously suppressed the migration and invasion of two cell lines and changed the morphological. Moreover, DATS inhibited the mRNA/protein/ enzymes activities of MMP2/9 via attenuating the NF-κB pathway. DATS also inhibited ERK/MAPK rather than p38 and JNK. CONCLUSION: DATS inhibits MMP2/9 activity and the metastasis of TNBC cells, and emerges as a potential anti-cancer agent. The inhibitory effects are associated with down-regulation of the transcriptional activities of NF-κB and ERK/MAPK signaling pathways.

Phenolcarboxylic acids from medicinal herbs exert anticancer effects through disruption of COX-2 activity.

Integrated research of herbs and formulas characterized by functions of promoting blood circulation and removing blood stasis is one of the most active fields in traditional Chinese medicine. This paper strives to demonstrate the roles of a homologous series of phenolcarboxylic acids from these medicinal herbs in cancer treatment via targeting cyclooxygenase-2 (COX-2), a well-recognized mediator in tumorigenesis. We selected thirteen typical phenolcarboxylic acids (benzoic acid derivatives, cinnamic acid derivatives and their dehydration-condensation products), and found gallic acid, caffeic acid, danshensu, rosmarinic acid and salvianolic acid B showed 50% inhibitory effects on hCOX-2 activity and A549 cells proliferation. 2D-quantitative method was introduced to describe the potential structural features that contributed to certain bioactivities. We also found these compounds underwent responsible hydrogen bonding to Arg120 and Ser353 in COX-2 active site residues. We further extensively focused on danshensu [d-(+)-ß-(3,4-dihydoxy-phenylalanine)] or DSS, which exerted COX-2 dependent anticancer manner. Both genetic and pharmacological inhibition of COX-2 could enhance the ability of DSS inhibiting A549 cells growth. Additionally, COX-2/PGE2/ERK signaling axis was essential for the anticancer effect of DSS. Furthermore, combined treatment with DSS and celecoxib could produce stronger anticancer effects in experimental lung metastasis of A549 cells in vivo. All these findings indicated that phenolcarboxylic acids might possess anticancer effects through jointly targeting COX-2 activity in cancer cells and provided strong evidence in cancer prevention and therapy for the herbs characterized by blood-activating and stasis-resolving functions in clinic.