The Saponin Monomer of Dwarf Lilyturf Tuber, DT-13, Reduces Human Breast Cancer Cell Adhesion and Migration during Hypoxia via Regulation of Tissue Factor

Abstract

In 2009, the most commonly diagnosed type of cancer among women in the United States was breast cancer, accounting for 27% (192370) of all new cancer cases.1) Despite improvements in detecting and treating the primary tumor, long-term survival is often compromised by the appearance of metastatic lesions in unrelated tissues such as the brain or bone.2) The metastatic dissemination of tumor cells requires the acquisition of biological properties including enhanced migratory behavior and the capacity to breach blood vessel walls and the dense collagenous matrix surrounding tumors.3,4) Currently, there is no effective therapy for this cancer in the advanced stages after metastasis, and new approaches are urgently needed to treat such a malignant disease.Hypoxia is an important factor that promotes cancer metastasis. 5,6) In contrast to established cell lines cultured under normal oxygen concentrations, tumors in the body grow under a specific internal environment characterized by much lower oxygen concentrations. Tissue factor (TF) is frequently over-expressed in human tumors and exhibits dual influences through its signaling and procoagulant activity. 7)In some cases, tumor cells were found to ectopically produce the main TF ligand, plasma protein factor VII, an observation that may suggest a cancer-specific 'autocrine' activation of the TF pathway.7) These new observations of TF suggest this unique molecule can be exploited in various ways to treat human cancer. As it is functionally involved in tumor initiation, growth and angiogenesis, TF could be a rational target for the development of agents to specifically kill tumor cells or block metastasis.8) Overall, several new findings related to TF create a fascinating prospect that this unique molecule could be explored in various ways to treat human cancer.Dwarf lilyturf tuber, a traditional Chinese medicinal (TCM) plant, is used widely in the clinics.9) The saponin monomer 13 of dwarf lilyturf tuber (DT-13), one of the saponin monomers of dwarf lilyturf tuber isolated from Ophiopogon japonicus (THUNB.) ker-Gaul, 9,10) has been found to exhibit anti-tumor effects.11) However, direct evidence for the mechanism of action of DT-13 on tumors during hypoxia is lacking. Interestingly, in our preliminary experiments, we found that DT-13 could inhibit hypoxia-induced adhesion of cancer cells. Thus, the purpose of this present study was to investigate the effects of DT-13 on human breast carcinoma metastasis in hypoxic conditions, and explore the possible mechanism of DT-13 against tumor metastases. MATERIALS AND METHODS Cell Lines and Cell CultureHuman breast carcinoma MDA-MB-435 cells were cultured as monolayers in Dulbecco's modified Eagle's medium media (DMEM, Gibco) supplemented with 10% fetal calf serum (FCS, Gibco), 100 U/ml penicillin and 100 mg/ml streptomycin. To create hypoxic conditions, 70-80% confluent cells were placed in an anaerobic chamber (HERAcell 150, Thermo) with 1% O 2 and 5% CO 2 at 37°C.Cytotoxicity Assays Inhibitory effects were determined using t...

NF-κB-dependent increase in tissue factor expression is responsible for hypoxic podocyte injury

“…In cancer cells, such as glioma, lung cancer, and breast cancer hypoxia induces TF [15,16,17]. On the other hand, the expression of TF in podocytes under hypoxic conditions is not known.…”

Phytochemical and pharmacological overview on <i>Liriopes radix</i>

“…DT-13 decreased the migratory response by hypoxia also inhibited hypoxia induced expression of V3 integrin, tissue factor (TF), and early growth response gene-1 (Egr-1) and decreased excretion of MMP-9 of MDA-MB-435 cells. DT-13 also inhibits the up regulation of TF mRNA and protein levels and its pro-coagulant activity under hypoxia [62]. Furthermore, DT-13 inhibited the phosphorylation of p38 in MDA-MB-435 cells [63].…”

The influence of YS-1 on the Dll4-Notch1 signaling pathway

“…In order to investigate the alteration of the Dll4-Notch1 protein expression levels by YS-1, p43 siRNA, and pcDNA þ -p43, immunoblotting analysis was performed as previously described [18]. Briefly, adherent cells were washed twice with phosphate-buffered saline (PBS), and then lysed in RIPA buffer.…”