Bone Regeneration Laboratory, Research Institute Codivilla-Putti, Rizzoli Orthopaedic Institute, Via di Barbiano 1/10, 40136 Bologna, Italy.
Toxicol In Vitro. 2012 Feb;26(1):142-9. doi: 10.1016/j.tiv.2011.10.009. Epub 2011 Oct 25.
Natural derivatives of vitamin A, including all-trans-retinoic acid (ATRA), commonly known as retinoids, currently produce favorable results in the treatment of many types of tumors. The rexinoid 6-OH-11-O-hydroxyphenantrene (IIF) is a synthetic derivative of ATRA. Previous in vitro and in vivo studies demonstrated that IIF is able to induce growth inhibition of various cancer cells and is a potent apoptosis-inducing agent with clinical potential. Osteosarcoma (OS) is the most common type of bone cancer, characterized by a rising aggressiveness. Recent evidences suggest that mesenchymal stem cells (MSC) may favour tumor growth and progression. Thus, it is important to investigate whether a compound with potential anti-tumoral properties such as IIF affects not only tumor cells but also MSC. The current study is an attempt to understand the mode of the potential cytotoxicity of IIF on OS cells and MSC. The response to IIF treatment of osteosarcoma SaOS-2, MG63, and U2OS cells and of bone marrow-derived MSC was the subject of investigation. The results showed that IIF significantly inhibited cell growth in OS cell lines and MSC in both a time- and dose-dependent manner, as evaluated by methylene blue assay. This was also associated with altered cell morphology and an increase in cell death with the involvement of apoptosis as demonstrated by NucleoCounter, Hoechst 33342 staining and FACS analysis. No cell death and apoptosis was found in U2OS cells. Analysis of cells treated with 20 and 40μM IIF for 24h by western blot suggests the activation of initiator caspase 9, indicating the involvement of caspases in inducing apoptosis. Furthermore, IIF upregulated the expression of the pro-apoptotic protein Bax and downregulated the anti-apoptotic protein Bcl2. For the first time, our results collectively provide an evidence for cell growth inhibition and activation of apoptosis in human OS cells and MSC by IIF. These results confirm that IIF may be an effective compound for anticancer treatment, including that of OS.
天然维生素 A 的衍生物，包括全反式维甲酸（ATRA），通常被称为维甲酸，目前在治疗多种类型的肿瘤方面取得了良好的效果。瑞香素 6-OH-11-O-羟基菲（IIF）是 ATRA 的合成衍生物。先前的体外和体内研究表明，IIF 能够诱导各种癌细胞的生长抑制，并且是一种具有临床潜力的强效凋亡诱导剂。骨肉瘤（OS）是最常见的骨癌类型，其特征是侵袭性不断增加。最近的证据表明，间充质干细胞（MSC）可能有利于肿瘤的生长和进展。因此，研究具有潜在抗肿瘤特性的化合物（如 IIF）是否不仅影响肿瘤细胞，而且还影响 MSC 非常重要。本研究旨在探讨 IIF 对 OS 细胞和 MSC 的潜在细胞毒性作用模式。研究了骨肉瘤 SaOS-2、MG63 和 U2OS 细胞和骨髓来源 MSC 对 IIF 治疗的反应。结果表明，IIF 以时间和剂量依赖的方式显著抑制 OS 细胞系和 MSC 的细胞生长，通过亚甲基蓝测定评估。这也与细胞形态的改变以及涉及凋亡的细胞死亡增加有关，如 NucleoCounter、Hoechst 33342 染色和 FACS 分析所示。在 U2OS 细胞中未发现细胞死亡和凋亡。用 20 和 40μM IIF 处理 24 小时的细胞的 Western blot 分析表明起始半胱天冬酶 9 的激活，表明半胱天冬酶参与诱导凋亡。此外，IIF 上调促凋亡蛋白 Bax 的表达并下调抗凋亡蛋白 Bcl2。我们的结果首次提供了证据表明 IIF 可抑制人骨肉瘤细胞和 MSC 的细胞生长并激活细胞凋亡。这些结果证实，IIF 可能是一种有效的抗癌治疗化合物，包括骨肉瘤。
