Ocimum basilicum (basil polysaccharide, BPS) and the effects of curcumin and BPS on the invasion activity of the SKOV3 ovarian cancer cells and human monocyte-derived dendritic cells

In the present study, a polysaccharide extract was obtained from Ocimum basilicum (basil polysaccharide, BPS) and the effects of curcumin and BPS on the invasion activity of the SKOV3 ovarian cancer cells and human monocyte-derived dendritic cells (DCs) were investigated. SKOV3 cells and immature or mature DCs were treated with 50 μM curcumin or 100 μg/ml BPS. A transwell invasion assay demonstrated that curcumin and BPS differentially regulate the invasion of SKOV3 cells and DCs. Curcumin significantly decreased the invasion of SKOV3 cells and immature and mature DCs, while BPS only decreased SKOV3 cell invasion. Osteopontin (OPN) mRNA and protein expression were significantly reduced in curcumin and BPS-treated SKOV3 cells and curcumin‐treated DCs. Furthermore, flow cytometry showed that curcumin significantly inhibited the surface expression of CD44 in SKOV3 cells and DCs, while BPS had a minimal effect on CD44 expression. Matrix metallopeptidase-9 (MMP-9) mRNA and protein expression were also reduced in all curcumin-treated cells and BPS-treated SKOV3 cells. The results indicated that curcumin and BPS regulated invasion of SKOV3 cells and DCs by distinctly downregulating OPN, CD44 and MMP-9 expression. Therefore, Curcumin and BPS may be suitable candidates for DC-based vaccines for ovarian cancer immunotherapy. Introduction Ovarian cancer is one of the most common types of malignancy in females worldwide, with an estimated 225,500 novel cases and 140,200 cancer-related mortalities occurring annually (1). Although chemotherapy for ovarian cancer has been well established throughout the last three decades, the 5-year survival rate remains <50%, the lowest of all gynecological malignancies. The cause for this is that ovarian cancer tends to have distantly metastasized by the time the majority of cases are diagnosed (1). Local invasion is an initiating step in cell migration and commonly occurs prior to distant metastasis; therefore, decreasing invasion activity of cancer cells may improve the outcome of ovarian cancer patients. In healthy individuals, malignant cells are under the surveillance of immune cells to resist invasion and metastasis, which is an essential aspect of anticancer immunity. Dendritic cells (DCs) are known to be the most specialized antigen-presenting cells and are important in the development of anticancer immune responses as they control the initiation and polarization of adaptive immunity (2). A previous clinical trial showed promising results achieved by DC vaccination in advanced ovarian cancer patients, with 90% overall survival during 36 months of observation (3). Fulfilling this function, however, is dependent upon the migration of DCs to T-cell-rich lymph organs following the uptake of the vaccination and the presentation of tumor antigens. Inhibition of DC invasion activity facilitates tumor escape from host immune surveillance. A previous study indicated that intratumoral injection of DCs generated in vitro, fails to initiate systemic antitumor immunity as the DCs migrated into regional lymph nodes less efficiently (4). Thus, a complementary therapy, which decreases the motility of cancer cells without markedly affecting DC invasion, may be beneficial in preventing ovarian cancer metastasis. Cell invasion results from cross-talk between cells and the extracellular matrix (ECM). Osteopontin (OPN), a phosphorylated glycoprotein with pleiotropic properties, is expressed on the ECM and on the surface of a number of cells, including malignant cells, lymphocytes and vascular smooth muscle cells. OPN promotes cell adhesion and invasion in various Effects and mechanisms of curcumin and basil polysaccharide on the invasion of SKOV3 cells and dendritic cells JING LV1*, QIANQIAN SHAO1*, HUAYANG WANG1, HUAN SHI1, TING WANG1,2, WENJUAN GAO1, BINGFENG SONG1, GUANGJUAN ZHENG2, BEIHUA KONG3 and XUN QU1 1Institute of Basic Medical Sciences, Qilu Hospital of Shandong University, Jinan, Shandong 250012; 2Department of Pathology, Shandong University of Traditional Chinese Medicine, Changqing University Science and Technology Park, Jinan, Shandong 250355; 3Department of Gynaecology and Obstetrics, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China Received March 17, 2013; Accepted September 2, 2013 DOI: 10.3892/mmr.2013.1695 Correspondence to: Dr Xun Qu, Institute of Basic Medical Sciences, Qilu Hospital of Shandong University, 107 Wenhuaxi Road, Jinan, Shandong 250012, P.R. China E-mail: [email protected] *Contributed equally