Paclitaxel is the most commonly used chemotherapeutic agent in breast cancer treatment. In addition to its well-known cytotoxic effects, recent studies have shown that paclitaxel has tumor-supportive activities. Importantly, paclitaxel levels are not maintained at the effective concentration through one treatment cycle; rather, the concentration decreases during the cycle as a result of drug metabolism. Therefore, a comprehensive understanding of paclitaxel's effects requires insight into the dose-specific activities of paclitaxel and their influence on cancer cells and the host microenvironment. Here we report that a low dose of paclitaxel enhances metastasis of breast cancer cells to the liver in mouse models. We used microarray analysis to investigate gene expression patterns in invasive breast cancer cells treated with low or clinically relevant high doses of paclitaxel. We also investigated the effects of low doses of paclitaxel on cell migration, invasion and metastasis in vitro and in vivo. The results showed that low doses of paclitaxel promoted inflammation and initiated the epithelial-mesenchymal transition, which enhanced tumor cell migration and invasion in vitro. These effects could be reversed by inhibiting NF-jB. Furthermore, low doses of paclitaxel promoted liver metastasis in mouse xenografts, which correlated with changes in estrogen metabolism in the host liver. Collectively, these findings reveal the paradoxical and dosedependent effects of paclitaxel on breast cancer cell activity, and suggest that increased consideration be given to potential adverse effects associated with low concentrations of paclitaxel during treatment.
Metastasis of breast cancer is the vital step for malignant progression. During such a process, hematogenous metastasis is an indispensable approach for the dissemination of cancer cells. A platelet, contributes to hypercoagulable state, and is also identified the crucial factor in the coagulation system for supporting metastasis. Therefore, the relationship of a platelet and a tumor cell plays a critical role in tumor cell metastasis. Consequently, inhibiting tumor cell‑induced platelet aggregation (TCIPA) is recongnized as a crucial target on suppression of tumor metastasis such as aspirin (ASA). Under such circumstance, here we report that, through dissociating the tumor‑platelet (T‑P) complex, 80% ethanol extracts of Caulis Spatholobi (SET) successfully alleviated the hypercoagulation state, thereby reducing tumor metastasis and improving the prospects of survival in breast cancer cell model. Through MTT and anti‑aggregation assay stimulated by ADP, we detected the optimum treatment time and the optimum dose of SET. By using confocal microscopy, we observed that SET can strongly block the formation of T‑P complex in vitro. The result was further quantified and confirmed by the FACS analysis. The fluorescent value of T‑P complex was obviously decreased in the drug‑treated groups. In vivo, 4T1 cells were injected through the mouse tail vein for dynamic visualization by small animal imaging system. The metastatic intensity was quantified and the survival curve was analyzed. Additionally, general observation and hematoxylin and eosin (H&E) staining of lung tissue was performed. SET exerted an obvious effect on the inhibition of metastasis and increasing the survival rate of mice. For the molecular mechanism study of anti‑TCIPA, zymography and RT‑PCR assay preliminarily revealed the molecular mechanism of SET in the regulation of P‑T interaction. Collectively, through drug efficacy identification and pharmacological revealing, we have obtained a promising candidate for the interference of breast metastasis by suppressing TCIPA, which will be beneficial for clinical cancer treatment.
BackgroundThis study directly and dynamically investigated the effects of SL extract (i.e., a combination of Radix Salviae miltiorrhizae and Andrographis paniculata extract) on plaque progression in vivo by high resolution ultrasound biomicroscopy (UBM).MethodsAn atherosclerosis model was established by placing a perivascular collar on the right common carotid artery in apolipoprotein E-deficient (ApoE-/-) mice. Thickness, plaque area and local blood flow were observed by UBM, pathological changes were observed by histochemical staining, and lipid levels were measured by respective commercially available kits.ResultsCompared with the model group, the SL extract groups showed reduced wall thickness of the aortic arch (GC: P = 0.001, P = 0.002, and P < 0.001; LC: P < 0.001, P < 0.001, and P < 0.001; BC: P = 0.027, P = 0.017, and P = 0.003; respectively), which presented with retarded plaque progression of the cartoid artery with concordantly increased blood flow (P = 0.002 and P < 0.001) as visualized in vivo by UBM. Histological analysis confirmed the reduction of carotid atherosclerosis.ConclusionsThe SL extract inhibited the formation of atherosclerotic plaques in an ApoE-/- mice model by UBM analysis, and did so by effects that ameliorated local blood flow and improved blood lipid levels.
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