Zhang Jun, Ren Hening, Yuan Ping, Lang Wenhua, Zhang Li, Mao Li
Department of Thoracic/Head and Neck Medical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
Cancer Res. 2006 Jan 1;66(1):18-23. doi: 10.1158/0008-5472.CAN-04-3905.
We recently reported that a high level of hepatoma-derived growth factor (HDGF) expression in tumors correlates with a high incidence of tumor relapse or distant metastasis and shortened survival time in patients with non-small cell lung cancer (NSCLC). However, the mechanisms of the HDGF-associated aggressive biological behavior are unknown. In this study, we knocked down HDGF expression in NSCLC cells to determine the biological consequences. Transfection with HDGF-specific small interfering RNA (siRNA) resulted in down-regulation of HDGF expression in four NSCLC cell lines. Down-regulation of HDGF resulted in no detectable effect on anchorage-dependent cell growth as determined with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, a microelectronic cell sensor system, and flow cytometry. In contrast, cells transfected with HDGF-siRNA grew more slowly and formed significantly fewer colonies in soft agar than did cells treated with LipofectAMINE alone or transfected with negative control siRNA. In an in vitro invasion assay, significantly fewer cells transfected with HDGF-siRNA than cells treated with LipofectAMINE alone were able to invade across a Matrigel membrane barrier. In an in vivo mouse model, A549 cells treated with HDGF-siRNA grown significantly slower than the cells treated with LipofectAMINE alone or negative control siRNA. Morphologically, HDGF-siRNA-treated tumors exhibited markedly reduced blood vessel formation and increased necrosis, whereas the Ki67 labeling indices were similar in tumors treated with controls. Our results suggest that HDGF is involved in anchorage-independent growth, cell invasion, and formation of neovasculature of NSCLC. These qualities may contribute to the HDGF-associated aggressive biological behavior of NSCLC.
我们最近报道，肿瘤中高水平的肝癌衍生生长因子（HDGF）表达与非小细胞肺癌（NSCLC）患者的肿瘤复发或远处转移高发生率以及生存时间缩短相关。然而，HDGF相关侵袭性生物学行为的机制尚不清楚。在本研究中，我们敲低NSCLC细胞中HDGF的表达以确定生物学后果。用HDGF特异性小干扰RNA（siRNA）转染导致四种NSCLC细胞系中HDGF表达下调。用3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐测定法、微电子细胞传感器系统和流式细胞术测定，HDGF下调对贴壁依赖性细胞生长没有可检测到的影响。相比之下，与单独用LipofectAMINE处理或用阴性对照siRNA转染的细胞相比，用HDGF-siRNA转染的细胞生长更慢，在软琼脂中形成的集落明显更少。在体外侵袭试验中，与单独用LipofectAMINE处理的细胞相比，用HDGF-siRNA转染的细胞能够穿过基质胶膜屏障侵袭的明显更少。在体内小鼠模型中，用HDGF-siRNA处理的A549细胞生长明显比单独用LipofectAMINE处理或阴性对照siRNA处理的细胞慢。形态学上，用HDGF-siRNA处理的肿瘤显示血管形成明显减少且坏死增加，而对照组处理的肿瘤中Ki67标记指数相似。我们的结果表明，HDGF参与NSCLC的非贴壁依赖性生长、细胞侵袭和新血管形成。这些特性可能导致NSCLC与HDGF相关的侵袭性生物学行为。
