Igarashi Kentaro, Kawaguchi Kei, Kiyuna Tasuku, Murakami Takashi, Yamamoto Norio, Hayashi Katsuhiro, Kimura Hiroaki, Miwa Shinji, Tsuchiya Hiroyuki, Hoffman Robert M
AntiCancer, Inc., San Diego, CA, U.S.A.
Department of Surgery, University of California, San Diego, CA, U.S.A.
Anticancer Res. 2017 Mar;37(3):1005-1011. doi: 10.21873/anticanres.11410.
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. IC values 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.
我们之前报道过咖啡因可通过干扰细胞周期来增强骨肉瘤和软组织肉瘤的化疗疗效。丙戊酸具有组蛋白脱乙酰酶（HDAC）抑制活性。我们还报道了在细胞系原位小鼠模型中，咖啡因与丙戊酸联合治疗对骨肉瘤原发肿瘤的抗肿瘤疗效。
在本研究中，我们在体外以及骨肉瘤自发和实验性肺转移小鼠模型中对骨肉瘤细胞系进行了咖啡因与丙戊酸的联合治疗。使用WST-8法测定143B-RFP人骨肉瘤细胞在暴露于咖啡因和丙戊酸72小时后的存活率。计算IC值和联合指数。通过胫骨原位注射143B-RFP细胞建立原发性骨肉瘤和自发肺转移的小鼠模型。从第7天开始，每周给药5次，持续4周，给予丙戊酸、咖啡因以及两种药物的联合制剂。原位注射6周后，切除肺组织样本并用荧光成像系统观察。通过尾静脉注射143B-RFP细胞建立实验性肺转移小鼠模型。从第0天开始，每周给药5次，持续4周，用这些药物治疗小鼠。
咖啡因和丙戊酸在体外均引起浓度依赖性细胞杀伤。观察到联合治疗具有协同疗效。在自发肺转移模型中，未治疗组（G1）的肺转移灶数量为9.0±2.6；咖啡因组（G2）为10.8±2.9；丙戊酸组（G3）为10.0±3.1；联合组（G4）为3.0±1.1；（对照组与联合组相比，p = 6.78E-5；丙戊酸组与联合组相比，p = 0.006；咖啡因组与联合组相比，p = 0.003）。在实验性肺转移模型中，联合组显著减少了肺转移并提高了总体生存率（p = 0.0005）。
在体外以及骨肉瘤自发和实验性肺转移小鼠模型中均观察到咖啡因与丙戊酸联合治疗的疗效。
