Setty Bhuvana A, Jin Yi, Houghton Peter J, Yeager Nicholas D, Gross Thomas G, Nelin Leif D
Division of Pediatric Hematology/Oncology/BMT, Nationwide Children's Hospital; Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital; and Department of Pediatrics, The Ohio State University, Columbus, USA.
Cell Physiol Biochem. 2016;39(2):802-13. doi: 10.1159/000447790. Epub 2016 Aug 1.
BACKGROUND/AIMS: Despite significant advancements in the diagnosis and treatment of osteosarcoma, the overall survival has remained relatively unchanged for over two decades. Hypoxic conditions have been demonstrated in solid tumors and are associated with increased cell proliferation and angiogenesis. L-arginine metabolism by arginase produces L-ornithine, the precursor for polyamine and proline synthesis required for cellular proliferation. We hypothesized that hypoxia would increase cellular proliferation via arginase induction in human osteosarcoma cell lines.
We utilized a variety of approaches to examine the role of arginase II in hypoxic (1% O2, 5% CO2) cellular proliferation.
Arginase II mRNA and protein levels were significantly increased in osteosarcoma cells exposed to hypoxia for 48 hours. There were twice as many viable cells following 48 hours of hypoxia than following 48 hours of normoxia (21% O2, 5% CO2). The addition of difluoromethylornithine (DFMO), a putative arginase inhibitor, prevented hypoxia-induced proliferation. Transfection of small interfering RNAs (siRNA) targeting arginase II resulted in knockdown of arginase II protein levels and prevented hypoxia-induced cellular proliferation.
These data support our hypothesis that hypoxia increases proliferation of osteosarcoma cells in an arginase II-dependent manner. We speculate that arginase II may represent a therapeutic target in osteosarcoma.
背景/目的：尽管骨肉瘤的诊断和治疗取得了显著进展，但二十多年来总体生存率相对未变。实体瘤中已证实存在缺氧情况，且与细胞增殖和血管生成增加有关。精氨酸酶介导的L-精氨酸代谢产生L-鸟氨酸，它是细胞增殖所需的多胺和脯氨酸合成的前体。我们推测缺氧会通过诱导人骨肉瘤细胞系中的精氨酸酶来增加细胞增殖。
我们采用多种方法来研究精氨酸酶II在缺氧（1%氧气，5%二氧化碳）细胞增殖中的作用。
暴露于缺氧环境48小时的骨肉瘤细胞中，精氨酸酶II的mRNA和蛋白水平显著增加。缺氧48小时后的活细胞数量是常氧（21%氧气，5%二氧化碳）48小时后的两倍。添加假定的精氨酸酶抑制剂二氟甲基鸟氨酸（DFMO）可阻止缺氧诱导的增殖。转染靶向精氨酸酶II的小干扰RNA（siRNA）导致精氨酸酶II蛋白水平降低，并阻止了缺氧诱导的细胞增殖。
这些数据支持我们的假设，即缺氧以精氨酸酶II依赖的方式增加骨肉瘤细胞的增殖。我们推测精氨酸酶II可能是骨肉瘤的一个治疗靶点。
