Zhu Xi-Ling, Liang Li, Ding Yan-Qing
Department of Pathology, Southern Medical University, Guangzhou 510515 Guangdong Province, China.
Int J Colorectal Dis. 2008 Nov;23(11):1041-7. doi: 10.1007/s00384-008-0520-2. Epub 2008 Jul 30.
Formin-like 2 (FMNL2) is a member of diaphanous-related formins which can control the actin-dependent processes such as cell motility and invasion. In this study, we investigated the expression of FMNL2 in colorectal cancer (CRC) and its correlation with CRC metastasis.
PATIENTS-METHODS: Paraffin-embedded specimens of CRC (including 75 primary CRC tumors and 45 corresponding metastatic lymph nodes) and normal colorectal mucosa (30 samples) were immunostained with a FMNL2 antibody. Thirty-two paired snap-frozen tumor tissues and adjacent normal colorectal mucosa were subjected to real-time reverse-transcription polymerase chain reaction (RT-PCR). Six CRC cell lines (SW480, SW620, SW480/M5, LoVo, LS174T, and HT29) were assayed for FMNL2 expression by Western blotting and real-time RT-PCR. Their invasive abilities in vitro were determined by Boyden chamber assay.
The immunohistochemical analysis showed FMNL2 expression was considerably higher in CRC tumors and corresponding metastatic lymph nodes than in normal colorectal mucosa (P < 0.05, respectively). Elevated FMNL2 expression was significantly correlated with lymphatic metastasis of CRC (P < 0.05). Real-time RT-PCR analysis confirmed the results obtained by immunohistochemistry. At mRNA and protein levels, FMNL2 expression was substantially upregulated in cell lines derived from CRC metastases (SW620, SW480/M5, and LoVo) compared to ones derived from primary CRC (HT29, LS174T, and SW480; P < 0.05). In vitro cell invasive assay demonstrated that the former three cell lines had higher invasive ability than the latter cell lines.
FMNL2 may play an important role in the metastasis of CRC and may be a useful marker for metastasis of CRC.
类formin 2（FMNL2）是与透明质酸相关的formin家族成员，可调控肌动蛋白依赖性过程，如细胞迁移和侵袭。在本研究中，我们调查了FMNL2在结直肠癌（CRC）中的表达及其与CRC转移的相关性。
用FMNL2抗体对CRC石蜡包埋标本（包括75例原发性CRC肿瘤和45例相应的转移淋巴结）及正常结直肠黏膜（30份样本）进行免疫染色。对32对速冻肿瘤组织和相邻正常结直肠黏膜进行实时逆转录聚合酶链反应（RT-PCR）。通过蛋白质免疫印迹法和实时RT-PCR检测6种CRC细胞系（SW480、SW620、SW480/M5、LoVo、LS174T和HT29）中FMNL2的表达。通过Boyden小室试验测定它们在体外的侵袭能力。
免疫组化分析显示，CRC肿瘤及相应转移淋巴结中FMNL2的表达明显高于正常结直肠黏膜（P均<0.05）。FMNL2表达升高与CRC的淋巴转移显著相关（P<0.05）。实时RT-PCR分析证实了免疫组化结果。在mRNA和蛋白质水平上，与原发性CRC来源的细胞系（HT29、LS174T和SW480）相比，CRC转移来源的细胞系（SW620、SW480/M5和LoVo）中FMNL2表达显著上调（P<0.05）。体外细胞侵袭试验表明，前三种细胞系的侵袭能力高于后三种细胞系。
FMNL2可能在CRC转移中起重要作用，可能是CRC转移的一个有用标志物。
