Ai Xiao-Lan, Yao Fang, Wang Xiao-Jing, Duan Dong-Bei, Li Ke, Hu Zi-You, Yin Guo, Wang Mei, Wu Bing-Yi
Research Center of Clinical Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.E-mail:
Nan Fang Yi Ke Da Xue Xue Bao. 2018 May 20;38(5):511-519. doi: 10.3969/j.issn.1673-4254.2018.05.02.
To investigate the role of allograft inflammatory factor-1 (AIF-1) in colorectal cancer (CRC) progression and explore the possible mechanism.
The expression levels of AIF-1 in 70 CRC tissues and paired adjacent tissues were detected using immunohistochemistry and Western blotting, and the correlation of AIF-1 expression with the clinicopathological features of the patients was analyzed. In the CRC cell line SW480, the functional role of AIF-1 in regulating tumor progression was investigated by transfecting the cells with an AIF-1-overexpressing plasmid (AIF-1) and a negative control plasmid (NC). EdU proliferation assay and flow cytometry were used to assess the cell proliferation and cell cycle changes; Transwell migration assay and Annexin V-APC/7-AAD apoptosis assay kit were used to analyze the cell migration and apoptosis. The changes in the biological behaviors of the cells were observed after application of SB203580 to block the p38 MAPK pathway. The expression levels of CDK4, cyclin D1, P21, P27, MMP2, MMP9, Bax, Bcl2, Bcl-xl, p38 and p-p38 were detected using Western blotting.
AIF-1 was down-regulated in CRC tissues compared with the adjacent normal tissues, and its expression level was positively correlated with lymph node metastasis (P=0.008), TNM stage (P=0.003) and tumor size (P=0.023). Overexpression of AIF-1 in SW480 cells significantly reduced EdU-positive cells and caused obvious cell cycle arrest in G1 phase (P<0.05). AIF-1 overexpression resulted in significantly lowered protein expressions of CDK4 and cyclin D1, enhanced expressions of P21 and P27, attenuated cell migration ability (P<0.001), and decreased protein levels of MMP2 and MMP9. AIF-1 overexpression also induced obvious apoptosis of SW480 cells (P<0.01), significantly increased the protein levels of Bax and p-p38, and decreased the protein levels of Bcl-2 and Bcl-xl; SB203580 significantly attenuated the apoptosis-inducing effect of AIF-1 overexpression.
AIF-1 plays the role of a tumor suppressor in CRC by inhibiting cell proliferation, suppressing cell migration and inducing cell apoptosis. AIF-1 overexpression promotes the apoptosis of CRC cells by activating the p38 MAPK pathway.
探讨同种异体移植炎症因子-1（AIF-1）在结直肠癌（CRC）进展中的作用，并探索其可能机制。
采用免疫组织化学和蛋白质印迹法检测70例CRC组织及其配对的癌旁组织中AIF-1的表达水平，并分析AIF-1表达与患者临床病理特征的相关性。在CRC细胞系SW480中，通过转染AIF-1过表达质粒（AIF-1）和阴性对照质粒（NC），研究AIF-1在调节肿瘤进展中的功能作用。采用EdU增殖试验和流式细胞术评估细胞增殖和细胞周期变化；采用Transwell迁移试验和Annexin V-APC/7-AAD凋亡检测试剂盒分析细胞迁移和凋亡。应用SB203580阻断p38 MAPK通路后，观察细胞生物学行为的变化。采用蛋白质印迹法检测CDK4、细胞周期蛋白D1、P21、P27、基质金属蛋白酶2（MMP2）、基质金属蛋白酶9（MMP9）、Bax、Bcl-2、Bcl-xl、p38和p-p38的表达水平。
与癌旁正常组织相比，CRC组织中AIF-1表达下调，其表达水平与淋巴结转移（P=0.008）、TNM分期（P=0.003）和肿瘤大小（P=0.023）呈正相关。SW480细胞中AIF-1过表达显著减少EdU阳性细胞，并导致明显的G1期细胞周期阻滞（P<0.05）。AIF-1过表达导致CDK4和细胞周期蛋白D1蛋白表达显著降低，P21和P27表达增强，细胞迁移能力减弱（P<0.001），MMP2和MMP9蛋白水平降低。AIF-1过表达还诱导SW480细胞明显凋亡（P<0.01），显著增加Bax和p-p38蛋白水平，降低Bcl-2和Bcl-xl蛋白水平；SB203580显著减弱AIF-1过表达的促凋亡作用。
AIF-1通过抑制细胞增殖、抑制细胞迁移和诱导细胞凋亡，在CRC中发挥肿瘤抑制作用。AIF-1过表达通过激活p38 MAPK通路促进CRC细胞凋亡。
