1. Division of Molecular and Cellular Pathology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
2. Department of Cell Biology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan
3. Oral Pathology Section, Department of Surgical Pathology, Niigata University Hospital, 2-5274 Gakkoucho-dori, Chuo-ku, Niigata 951-8514, Japan
4. Department of Pathology, Niigata Cancer Center Hospital, 2-15-3 Kawagishi-cho, Chuo-ku, Niigata 951-8133, Japan
5. Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta 55281
6. Faculty of Medicine, Udayana University, Denpasar 80232, Bali, Indonesia
Pancreatic ductal adenocarcinoma (PDAC) is currently one of the most intractable malignancies with a typical scirrhous pattern in histology. Due to its abundant tumor stroma and scant vascularization, chemotherapeutic agents are considered inefficiently permeable to cancer nests, making it highly difficult to cure the patients with PDAC. However, PDAC is also considered to owe its intractability to other critical factors such as cellular interaction between tumor cells and tumor microenvironment as well as architectural barriers, which increases in therapeutic resistance. Here, we report a specific cellular interaction between PDAC cells and mesenchymal stem cells (MSCs) intermingled in PDAC stroma, which facilitates cancer invasion. Secretory phenotype profiling revealed that production of Amphiregulin (AREG) and MMP-3 were specifically upregulated under the coexistence of BxPC3 cells with human MSCs (approximately four to ten folds in AREG, and twenty to sixty-folds in MMP-3 compared to that of BxPC3 cells alone), whereas MMP-9 expression was decreased (less than one-tenth comparing with that of BxPC3 cells alone). Blockage of AREG production by its specific siRNA removed MSC-mediated driving force of BxPC3 invasiveness. Immunohistochemical analysis of tissue samples obtained both from PDAC patients and PDAC imitating mouse xenografted models revealed that significant coexpression of AREG and its receptor EGFR were detected on the cancer cells at invasive front. These results strongly suggested that cellular interaction between cancer cells and MSCs in the PDAC stroma might be critical to cancer progression, especially in the process of local invasion and the early stage development of metastasis.
Keywords: MSC, PDAC, microenvironment, stroma, AREG, MMP