Role of nitric oxide in pancreatic cancer cells exhibiting the invasive phenotype
Mayumi Fujita,
Veena Somasundaram,
Debashree Basudhar,
Robert Y.S. Cheng,
Lisa A. Ridnour,
Harumi Higuchi,
Kaori Imadome,
Jae Hong No,
Gaurav Bharadwaj,
David A. Wink
Affiliations
Mayumi Fujita
Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, MD, USA; Department of Basic Medical Sciences for Radiation Damages, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan; Corresponding author. Department of Basic Medical Sciences for Radiation Damages, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba-shi, Chiba-ken, 263-8555, Japan.
Veena Somasundaram
Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, MD, USA
Debashree Basudhar
Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, MD, USA
Robert Y.S. Cheng
Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, MD, USA
Lisa A. Ridnour
Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, MD, USA
Harumi Higuchi
Department of Basic Medical Sciences for Radiation Damages, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
Kaori Imadome
Department of Basic Medical Sciences for Radiation Damages, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
Jae Hong No
Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, MD, USA; Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
Gaurav Bharadwaj
Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, MD, USA
David A. Wink
Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, MD, USA; Corresponding author. Cancer and Inflammation Program, National Cancer Institute, Bldg. 567 Rm 254, 1050 Boyles St., Frederick, MD 21702, USA,
Pancreatic cancer is a highly metastatic tumor with an extremely low 5-year survival rate. Lack of efficient diagnostics and dearth of effective therapeutics that can target the cancer as well as the microenvironment niche are the reasons for limited success in treatment and management of this disease. Cell invasion through extracellular matrix (ECM) involves the complex regulation of adhesion to and detachment from ECM and its understanding is critical to metastatic potential of pancreatic cancer. To understand the characteristics of these cancer cells and their ability to metastasize, we compared human pancreatic cancer cell line, PANC-1 and its invading phenotype (INV) collected from transwell inserts. The invasive cell type, INV, exhibited higher resistance to Carbon-ion radiation compared to whole cultured (normally dish-cultured) PANC-1 (WCC), and had more efficient in vitro spheroid formation capability. Invasiveness of INV was hampered by nitric oxide synthase (NOS) inhibitors, suggesting that nitric oxide (NO) plays a cardinal role in PANC-1 invasion. In addition, in vitro studies indicated that a MEK-ERK-dependent, JAK independent mechanism through which NOS/NO modulate PANC-1 invasiveness. Suspended INV showed enhanced NO production as well as induction of several pro-metastatic, and stemness-related genes. NOS inhibitor, l-NAME, reduced the expression of these pro-metastatic or stemness-related genes, and dampened spheroid formation ability, suggesting that NO can potentially influence pancreatic cancer aggressiveness. Furthermore, xenograft studies with INV and WCC in NSG mouse model revealed a greater ability of INV compared to WCC, to metastasize to the liver and l-NAME diminished the metastatic lesions in mice injected with INV. Overall, data suggest that NO is a key player associated with resistance to radiation and metastasis of pancreatic cancer; and inhibition of NOS demonstrates therapeutic potential as observed in the animal model by specifically targeting the metastatic cells that harbor stem-like features and are potentially responsible for relapse. Keywords: Nitric oxide, Nitric oxide synthase, Pancreatic cancer, Invasion, Metastasis, Cancer stem cell
