Deng Biyong, Feng Youwei, Deng Bixiang
Cell Physiol Biochem. 2015;37(6):2434-43. doi: 10.1159/000438596. Epub 2015 Dec 10.
BACKGROUND/AIMS: Osteosarcoma (OS) is a primary malignant bone tumor in humans, and is notorious mainly for its distal metastases. We have recently shown that Shikonin, an effective constituent extracted from Chinese medicinal herb, inhibits OS cell invasion through suppression of matrix metalloproteinase 13 (MMP13). However, the underlying mechanisms remain unknown.
Here, we studied the levels of tumor necrosis factor (TNF)-alpha-induced protein 8-like 2 (TIPE2) in OS cells upon Shikonin treatment. TIPE2 levels were adapted in OS cell lines through transfection with plasmids carrying transgene or short-hairpin interference RNA (shRNA), and the effects of TIPE2 adaptation on MMP13 and cell invasiveness were evaluated by RT-qPCR, Western blot, ELISA and transwell cell migration assay, respectively. TIPE2 levels in OS specimens from patients were examined and correlated with cancer metastases and patient survival.
We found that Shikonin dose-dependently decreased MMP13 levels, and increased TIPE2 levels in two OS cell lines, U2OS and SaOS-2. Overexpression of TIPE2 in U2OS significantly suppressed MMP13 levels and cell invasiveness. Depletion of TIPE2 in SaOS-2 cells significantly increased MMP13 levels and cell invasiveness. Moreover, TIPE2 levels in OS specimens were significantly decreased, compared to adjacent non-cancer bone tissue. Lower TIPE2 levels correlated with higher incidence of metastases and worse 5-year survival.
TIPE2 mediates the suppressive effects of Shikonin on MMP13 in osteosarcoma cells, and TIPE2 may be a novel therapeutic target for OS.
背景/目的：骨肉瘤（OS）是人类原发性恶性骨肿瘤，主要因其远处转移而臭名昭著。我们最近发现，从中药中提取的有效成分紫草素通过抑制基质金属蛋白酶13（MMP13）来抑制OS细胞侵袭。然而，其潜在机制仍不清楚。
在此，我们研究了紫草素处理后OS细胞中肿瘤坏死因子（TNF）-α诱导蛋白8样2（TIPE2）的水平。通过用携带转基因的质粒或短发夹干扰RNA（shRNA）转染来调节OS细胞系中的TIPE2水平，并分别通过RT-qPCR、蛋白质印迹、酶联免疫吸附测定和Transwell细胞迁移试验评估TIPE2调节对MMP13和细胞侵袭性的影响。检测患者OS标本中的TIPE2水平，并将其与癌症转移和患者生存率相关联。
我们发现紫草素在两种OS细胞系U2OS和SaOS-2中剂量依赖性地降低MMP13水平，并增加TIPE2水平。U2OS中TIPE2的过表达显著抑制MMP13水平和细胞侵袭性。SaOS-2细胞中TIPE2的缺失显著增加MMP13水平和细胞侵袭性。此外，与相邻的非癌骨组织相比，OS标本中的TIPE2水平显著降低。较低的TIPE2水平与较高的转移发生率和较差的5年生存率相关。
TIPE2介导紫草素对骨肉瘤细胞中MMP13的抑制作用，并且TIPE2可能是OS的一个新的治疗靶点。
