br Introduction br Colorectal cancer
Colorectal cancer (CRC) is one of the most common malignancies in the world. It is the third most commonly diagnosed cancer among both men and women in the United States, accounting for approximately 135,000 new cases and 50,000 deaths per year . The mortality of colon cancer is always ascribed to metastasis, and the most prominent type of distant metastasis observed in colon cancer is liver metastasis [2,3]. Cancer metastasis is known to be a complex multistep cascade. The epithelial-mesenchymal transition (EMT) is regarded as the most im-portant process of tumour invasion and metastasis, which is a crucial step in regulating the malignant behaviours of colon cancer A23187 [4–6]. Aside from traditional surgical treatment, chemotherapy and radiotherapy are still the two most effective methods for the prevention and treatment of
Correspondence to: S. Wang, The MOE Key Laboratory for Standardization of Chinese Medicine, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
CRC. However, these treatments are usually associated with multiple un-desirable side effects. The increasing toxicity profile and acquired chemo-therapy resistance are still important problems that need to be resolved. Hence, the development of therapeutic agents that can inhibit metastasis is crucial for improving the management of CRC.
Polysaccharides are an important type of biological macromolecules that are widely involved in the various activities of organisms. In recent years, natural polysaccharides have become the focus of research due to advantages such as having an immunity enhancement effect [7,8], antitumour activity [9–11], and few toxic and adverse side effects. These active polysaccharides have unique advantages for inhibiting can-cer cell proliferation, inducing apoptosis and suppressing cancer cell in-vasion and metastasis [12,13].
Scutellaria barbata D. Don (SB) is a traditional Chinese medicine from China. SB is a perennial herb of the Lamiaceae (mint) family that mainly grows in northeast Asia and has been used as an anti-inflammatory, an-tioxidant, antitumour agent and a diuretic in China. It has been clinically used for treating cancer, snake bites, and inflammatory diseases. It con-tains various types of bioactive substances, such as flavones, terpenoids, alkaloids and steroid compounds. In recent years, it has been found that
SB can inhibit many kinds of tumours, such as colorectal cancer [14,15], hepatocellular carcinoma , lung cancer [17,18], ovarian cancer , breast cancer , and skin cancer . However, there has been no fur-ther research on the polysaccharides of SB, in particular, studies relating to tumour invasion and metastasis are lacking.
In this study, we isolated a homogeneous polysaccharide from Scutellaria barbata D. Don, SBPW3. SBPW3 was characterized by HPLC analysis, monosaccharide composition analysis, and FT-IR. To verify the effect of SBPW3 on colon cancer cell metastasis, we established an epithelial-mesenchymal transition model by treating colon cancer cells (HT-29) with transforming growth factor-β1 (TGF-β1). This model was used to investigate the effect of SBPW3 on the invasive and metastatic abilities of colon cancer cells. These results provide ex-perimental evidence to support the future research of the polysaccha-rides of Scutellaria barbata D. Don.
2. Materials and methods
2.1. Materials and animals
The whole plant of Scutellaria barbata D. Don (Product No. 140409) was purchased from Kangqiao Medicinal Materials Electuary Co. Ltd. in Shanghai, China. A DEAE cellulose column was purchased from Yeli