Abstract
Alternative medicine has been highly advocated worldwide in recent decades. Botanical drugs, one major area of alternative medicine have been the most popularly used. Rhizoma polygoni cuspidati (rhizome of Polygonum cuspidatum, Hu-Zhang in Chinese) belongs to the family of Polygonaceae. It has been used for a long time in Asia. Traditional uses of rhizoma polygonum cuspidatum are treatments for arthralgia, chronic bronchitis, jaundice, amenorrhea, and high blood pressure. Several chemical compounds including stilbenes, anthraquinones and flavones were isolated from Polygonum cuspidatum extract (PCE), and natural ingredients, resveratrol and emodin, were selected to assess the effect of herbal drug. PCE has anti-inflammatory, cardio-protective, anti-proliferative, and antioxidant activities both in vitro and in vivo. Nasopharyngeal carcinoma (NPC) is a non-lymphomatous, non-keratinising squamous carcinomas or keratinising squamous-cell carcinomas, prevalent in southeastern Asia, southern part of China and Taiwan. This disease occurs in the epithelia lining of the retronasal cavity. Epstein-Barr virus (EBV) is regarded as one of the etiological factors in tumorigenesis of nasopharyngeal carcinoma. An EBV-negative nasopharyngeal carcinoma cell line, TW01, and EBV-positive nasopharyngeal carcinoma cell line, NA, were uesd as the model in this study. The main goal of this study is to investigate whether PCE could inhibit human NA and TW01 nasopharyngeal carcinoma cell proliferation and anti-tumor activities. The results of cytotoxicity assay revealed that PCE could inhibit cell gorwth in a dose-dependent manner. IC50 values of two NPC cell lines revealed that the toxicity of PCE to nasopharyngeal carcinoma cell lines was low. To assess whether PCE had anti-tumor activity in low cytotoxicity, migration, invasion and gelatin zymograph assays were carried out. Treatment with PCE could suppress migratory and invasive abilities signigicantly in NPC cells, and gelatin zymograph assay indicated that PCE could reduce matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) activities. The expression of one mediator in Wnt signaling pathway, β-catenin, and cell adhsion component, E-cadherin, and MMP regulators, NF-κB and Sp1 were affected upon treatment of PCE. Taken together, these results indicate that PCE can effectively inhibit cell growth, migration and invasion of NPC cells through regulation of the expression of β-catenin, E-cadherin, NF-κB and Sp1 at nuclear and cytoplasmic levels. In conclusion, Polygonum cuspidatum extract is potentially a botanical supplement for cancer metastatic therapy.