[Role of allograft inflammatory factor-1 in regulating the proliferation, migration and apoptosis of colorectal cancer cells].

OBJECTIVE: To investigate the role of allograft inflammatory factor-1 (AIF-1) in colorectal cancer (CRC) progression and explore the possible mechanism. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Glia maturation factor beta is required for reactive gliosis after traumatic brain injury in zebrafish.

Gliosis is a hallmark of neural pathology that occurs after most forms of central nervous system (CNS) injuries including traumatic brain injury (TBI). Identification of genes that control gliosis may provide novel treatment targets for patients with diverse CNS injuries. Glia maturation factor beta (GMFB) is crucial in brain development and stress response. In the present study, GMFB was found to be widely expressed in adult zebrafish telencephalon. A gmfb mutant zebrafish was created using CRISPR/cas9. In the uninjured zebrafish telencephalon, glial fibrillary acidic protein (GFAP) fibers in gmfb mutants were disorganized and shorter than wild type zebrafish. After TBI, transformation of quiescent type I radial glial cells (RGC) to proliferative type II RGCs was significantly suppressed in the gmfb mutant. RGC proliferation and hypertrophy post-TBI was reduced in gmfb mutants, indicating that reactive gliosis was attenuated. TBI-induced acute inflammation was also found to be alleviated in the gmfb mutant. Morphological changes also suggest attenuation of microglial reactive gliosis. In a mouse model of TBI, GMFB expression was increased around the injury site. These GMFB+ cells were identified as astrocytes and microglia. Taken together, the data suggests that GMFB is not only required for normal development of GFAP fibers in the zebrafish telencephalon, but also promotes reactive gliosis after TBI. Our findings provide novel information to help better understand the reactive gliosis process following TBI.