Content area
Full text
Introduction
Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer-related death in females worldwide, with an estimated 1.7 million cases and 521,900 deaths in 2012 (1). Metastases to distant sites are common (2). Approximately 65–75% of patients with advanced breast cancer may develop bone metastases (3). Remarkable progress has been made in the treatment of breast cancer. However, despite these advances, the mortality rate is still high, mainly due to metastatic spread (4). Therefore, the development of new agents for breast cancer is important to reduce the mortality caused by this disease.
Natural products are a very important source providing promising leads for the development of novel cancer therapeutics due to their potentially low toxicity profiles and potential effectiveness (5). Arctium lappa L., commonly known as burdock or bardana, is a traditional Chinese medicine and perennial plant of the Compositae family. Recent studies demonstrated that Arctium lappa L. has numerous pharmacological activities, including anti-inflammatory (6), antitumor (7), antioxidant (8) and antiviral activities (9). However, the information concerning the antitumor constituents in this plant is still limited.
Arctigenin is the main active constituent that is extracted and isolated from the fruit of Arctium lappa L. (10). Experimental studies have shown various pharmacological effects of arctigenin including its antitumor activity (11–14). However, the antimetastatic effects of arctigenin on human breast cancer cells remain unknown. In the present study, we investigated the antimetastatic effect of arctigenin in human breast cancer cells. Results of this investigation may provide a scientific explanation for the antimetastatic mechanism of arctigenin.
Materials and methods
Chemicals and reagents
Arctigenin, isolated from the fruit of Arctium lappa L., was kindly gifted by Dr Kunming Qin at Nanjing University of Traditional Chinese Medicine, and dissolved in dimethyl sulfoxide (DMSO) at a final concentration of 10 mM. The purity of arctigenin was above 98% (confirmed by high performance liquid chromatography and spectral analysis). Antibodies against MMP-2 (#4022), MMP-9 (#13667) and β-tubulin (#2128) for western blot analysis were obtained from Cell Signaling Technology (Beverly, MA, USA). An antibody against heparanase (ab42817) was obtained from Abcam (Cambridge, UK). 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and DMSO were purchased from Sigma-Aldrich (St. Louis, MO, USA). Fetal bovine serum (FBS) was purchased from BD Pharmingen (San Diego, CA, USA).