Deferasirox, an oral iron chelator, with gemcitabine synergistically inhibits pancreatic cancer cell growth in vitro and in vivo

// Shuhei Shinoda 1 , Seiji Kaino 1 , Shogo Amano 1 , Hirofumi Harima 1 , Toshihiko Matsumoto 1, 2 , Koichi Fujisawa 1 , Taro Takami 1 , Naoki Yamamoto 1 , Takahiro Yamasaki 2 and Isao Sakaida 1 1 Department of Gastroenterology and Hepatology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan 2 Department of Oncology and Laboratory Medicine, Yamaguchi University, Graduate School of Medicine, Yamaguchi, Japan Correspondence to: Taro Takami, email: t-takami@yamaguchi-u.ac.jp Keywords: deferasirox; iron chelator; gemcitabine; pancreatic cancer; ribonucleotide reductase Received: March 10, 2017      Accepted: April 28, 2018      Published: June 19, 2018 ABSTRACT Objectives: Iron is an essential element for cell proliferation and growth processes. We have reported that deferasirox (DFX), an oral iron chelator, showed antiproliferative activity against pancreatic cancer cells. This study aimed to elucidate the effects of combination of gemcitabine (GEM), standard chemotherapy for pancreatic cancer, and DFX in vitro and in vivo . Results: GEM+DFX showed antiproliferative activity and induced apoptosis in pancreatic cancer cells in vitro . GEM+DFX suppressed xenograft tumor growth and induced apoptosis without any serious side effects compared with control, GEM, and DFX (average tumor volume: control 697 mm 3 vs GEM 372 mm 3 , p < 0.05; GEM 372 mm 3 vs GEM+DFX 234 mm 3 , p < 0.05). RRM1 and RRM2 protein levels were substantially reduced by DFX in BxPC-3 in vitro . Conclusion: GEM+DFX has significant anticancer effects on pancreatic cancer cell through RR activity suppression. Methods: BxPC-3, a human pancreatic cancer cell line, was used in all experiments. Cellular proliferation rate was measured using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt assay. Apoptosis was evaluated by flow cytometry and by measuring caspase 3/7 activity with luminescence assay. In the tumor xenografts in nude mice models, when five weeks after engraftment, drug administration began (day 0). After treatment for 21 days, the mice were sacrificed and the tumors were excised. Apoptotic cells in xenografts were evaluated by terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling assay. Protein levels of ribonucleotide reductase (RR) subunit 1 (RRM1) and RR subunit 2 (RRM2) in BxPC-3 cells were assessed by western blot in vitro .