Anticancer Potential of Aguerin B, a Sesquiterpene Lactone Isolated from Centaurea behen in Metastatic Breast Cancer Cells.

BACKGROUND: Breast carcinoma is a malignant disease that represents the most common non-skin malignancy and a chief reason of cancer death in women. Large interest is growing in the use of natural products for cancer treatment, especially with goal of suppression angiogenesis, tumor cell growth, motility, as well as invasion and metastasis with low/no toxicity. It is evident from recent patents on the anticancer properties of sesquiterpene lactones such as parthenolide. OBJECTIVE: In this study, using MDA-MB-231 cells of a human breast adenocarcinoma, the effects of aguerin B, as a natural sesquiterpene lactone, has been evaluated, in terms of the expression of metastatic-related genes (Pak-1, Rac-1 and HIF-1α). METHODS: Cytotoxicity of aguerin B was tested toward MDA-MB-231 breast tumor cells using MTT. Scratch assay was accomplished to evaluate the tumor cell invasion. To understand the underlying molecular basis, the mRNA expressions were evaluated by real time PCR. RESULTS: It was found that aguerin B significantly inhibited human breast cancer cell growth in vitro (IC50 = 2µg/mL) and this effect was accompanied with a persuasive suppression on metastasis. Our results showed that aguerin B in IC50 concentration down-regulated Rac-1, Pak-1, Hif-1α and Zeb-1 transcriptional levels. CONCLUSION: Taken together, this study demonstrated that aguerin B possessed potential anti-metastatic effect, suggesting that it may consider as a potential multi target bio compound for treatment of breast metastatic carcinoma.

Verbascoside Attenuates Rac-1 and HIF-1α Signaling Cascade in Colorectal Cancer Cells.

OBJECTIVE: Metastasis phenotype is considered as the main challenge in colon cancer therapeutic methods. Furthermore, the side effects of conventional colorectal cancer treatment methods have attracted a lot of attention into natural ingredients. The aim of the study was to assess the molecular mechanism of verbascoside as natural bio-compound in human HT29 colon cancer cells. METHODS: HT29 cells were cultured in RPMI-1640 medium containing 10% FBS and 1% penicillin/ streptomycin at 37°C and 5% CO2. HT-29 cells were treated with different concentrations of verbascoside (10, 20, 30, 40, 50, 70, 100 µg/ml) for 24 hours, then MTT assay was used to calculate 50% inhibitory concentration. The migration of the colon cancer cells was evaluated by scratch assay. To evaluate involved antiproliferative mechanism, Rac-1 (Ras-related C3 botulinum toxin substrate 1) and HIF-1α (hypoxia-inducible factor-1α) related gene expression were evaluated by Real Time PCR. RESULTS: The results showed that verbascoside inhibited HT29 colon cancer cell proliferation dose-dependently and IC50 was evaluated as 50 µg/ml (***P<0.001). The results of wound healing assay demonstrated verbascoside decreased cell migration in a dose dependent manner. In the IC50 treated HT29 cells metastatic progression was significantly suppressed as **P<0.01. The results of Real Time PCR showed an attenuating effect of verbascoside on Rac-1, Zeb-1 (zinc finger E-box binding homeobox 1), Arp2 (Actin-Related Proteins), Pak1 (p21 (RAC1) activated kinase 1), VEGF (Vascular endothelial growth factor) and HIF-1α as Epithelial-Mesenchymal Transition markers. The down regulation of mRNA levels was Rac-1= 15.38, HIF-1 α = 16.66, Pak-1, Arp-2= 6.25, VEGF=24.39, Zeb-1=35.71 in HT29 cells treated with IC50 concentration of verbascoside. CONCLUSION: Colorectal cancer cells induce Rac-1 and HIF-1α overexpression which plays an important role in the activation and progression of cell motility, angiogenesis and metastasis. Overall results showed that verbascoside elucidated significant anti-metastatic and anti-invasion activities through suppression of Rac-1, HIF-1α, and Zeb-1 signaling pathway and it may be a suitable candidate to overwhelm colon cancer metastatic phenotype.