Antimetastatic Efficacy of the Combination of Caffeine and Valproic Acid on an Orthotopic Human Osteosarcoma Cell Line Model in Nude Mice.
We have previously reported that caffeine can enhance chemotherapy efficacy of bone and soft tissue sarcoma via cell-cycle perturbation. Valproic acid has histone deacetylase (HDAC) inhibitory activity. We have also reported the anti-tumor efficacy of combination treatment with caffeine and valproic acid against osteosarcoma primary tumors in a cell-line orthotopic mouse model.



In this study, we performed combination treatment of caffeine and valproic acid on osteosarcoma cell lines in vitro and in spontaneous and experimental lung metastasis mouse models of osteosarcoma. Survival of 143B-RFP human osteosarcoma cells after exposure to caffeine and valproic acid for 72 hours was determined using the WST-8 assay. IC50values and combination indices were calculated. Mouse models of primary osteosarcoma and spontaneous lung metastasis were obtained by orthotopic intra-tibial injection of 143B-RFP cells. Valproic acid, caffeine, and combination of both drugs were administered from day 7, five times a week, for four weeks. Six weeks after orthotopic injection, lung samples were excised and observed with a fluorescence imaging system. A mouse model of experimental lung metastasis was obtained by tail vein injection of 143B-RFP cells. The mice were treated with these agents from day 0, five times a week for four weeks.



Both caffeine and valproic acid caused concentration-dependent cell kill in vitro. Synergistic efficacy of the combination treatment was observed. In the spontaneous lung-metastasis model, the number of lung metastasis was 9.0±2.6 in the untreated group (G1); 10.8±2.9 in the caffeine group (G2); 10.0±3.1 in the valproic-acid group (G3); and 3.0±1.1 in the combination group (G4); (p=6.78E-5 control vs. combination; p=0.006 valproic acid vs. combination; p=0.003 caffeine vs. combination). In the experimental lung-metastasis model, the combination group significantly reduced lung metastases and improved overall survival (p=0.0005).



Efficacy of the combination of caffeine and valproic acid was observed in vitro and in spontaneous and experimental lung-metastasis mouse models of osteosarcoma.
AntiCancer, Inc., San Diego, CA, U.S.A.|Department of Surgery, University of California, San Diego, CA, U.S.A.|Department of Orthopaedic Surgery, Kanazawa University, Kanazawa, Japan.
Kentaro
K
Igarashi
AntiCancer, Inc., San Diego, CA, U.S.A.|Department of Surgery, University of California, San Diego, CA, U.S.A.
Kei
K
Kawaguchi
AntiCancer, Inc., San Diego, CA, U.S.A.|Department of Surgery, University of California, San Diego, CA, U.S.A.
Tasuku
T
Kiyuna
AntiCancer, Inc., San Diego, CA, U.S.A.|Department of Surgery, University of California, San Diego, CA, U.S.A.
Takashi
T
Murakami
Department of Orthopaedic Surgery, Kanazawa University, Kanazawa, Japan.
Norio
N
Yamamoto
Department of Orthopaedic Surgery, Kanazawa University, Kanazawa, Japan.
Katsuhiro
K
Hayashi
Department of Orthopaedic Surgery, Kanazawa University, Kanazawa, Japan.
Hiroaki
H
Kimura
Department of Orthopaedic Surgery, Kanazawa University, Kanazawa, Japan.
Shinji
S
Miwa
Department of Orthopaedic Surgery, Kanazawa University, Kanazawa, Japan all@anticancer.com tsuchi@med.kanazawa-u.ac.jp.
Hiroyuki
H
Tsuchiya
AntiCancer, Inc., San Diego, CA, U.S.A. all@anticancer.com tsuchi@med.kanazawa-u.ac.jp.|Department of Surgery, University of California, San Diego, CA, U.S.A.
Robert M
RM
Hoffman
D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001859:Bone Neoplasms / Q000188:drug therapy; D002110:Caffeine / Q000008:administration & dosage*; D016923:Cell Death; D045744:Cell Line, Tumor; D002470:Cell Survival; D006801:Humans; D020128:Inhibitory Concentration 50; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis / Q000188:drug therapy*; D009368:Neoplasm Transplantation; D012516:Osteosarcoma / Q000188:drug therapy*; D014635:Valproic Acid / Q000008:administration & dosage*
D002110:Caffeine; D014635:Valproic Acid
143B; Osteosarcoma; RFP; caffeine; combination therapy; nude mice; orthotopic; red fluorescent protein; valproic acid