Disclosures: The

following people have nothing to disclos

Disclosures: The

following people have nothing to disclose: Xiangmei Chen, Jun Lv, Pengfei Zhu, Fengmin Lu Background and Aims: Lymphoid enhancer factor/T cell factor proteins (LEF/TCFs) mediate Wnt signals by recruiting beta-catenin and its co-activators to Wnt response elements of target genes. This activity of LEF 1 is important during development and its dysregulation associated with progress of several types of cancers. However, the role and mechanisms of LEF1 on the progress of hepatocellular carcinoma (HCC) remain to be investigated. Methods: Resected human HCC samples from 20 patients with postoperative recurrence and 12 without were analyzed by expression array. Immunohistochemical (IHC) staining was performed in another independent validation set of 74 HCC tissue DAPT samples. Tumor sphere formation was carried out in ultralow plates. Soft agar colony formation and trans-well invasion were performed to study the effects of downregulation of LEF1 in Mahlavu cells on tumor behaviors. Nude mice were used in xenotransplant experiments. Real time reverse transcription PCR, Western blot analysis and reporter assays were carried out to study the regulation mechanism of LEF1

on the expression of Twist, Snail, Slug, Vimentin and Oct4 genes. Chromatin immunoprecipitation Selleck Carfilzomib (ChIP) was performed to study the binding of LEF1 on promoter regions of EMT regulators and stemness genes. Results: Microarray analysis showed that LEF 1 was associated with postoperative recurrence which was validated by IHC staining in another HCC cohort (p<0.0001). Moreover, over-expression of LEF1 was associated with Twist over-expression (p=0.018), a trend of Snail over-expression (p=0.064), multi-nodular tumors (p=0.025). In multivariate analysis, Methamphetamine LEF 1 was one of the factors significantly associated with recurrence (p=0.002). Tumor sphere of Mahlavu cells showed upregulation of, beta-catenin, LEF1, Twist, Snail, Slug, Oct4 and increased trans-well invasion. Downregulation of LEF1 by shRNA decreased Twist, Snail, Slug, Vimentin and Oct4

gene expression both in RNA and protein levels. Tumor sphere, soft agar colony formation, trans-well invasion were also decreased. Xenotransplant of Mahlavu cells with knockdown of LEF1 in nude mice showed smaller tumors compared to those parental Mahlavu cells. ChIP assay and reporter assays revealed that LEF1 can physically interact with and transcrip-tionally activate the promoter regions of Oct4, Snail, Slug and Twist. Conclusion: Taken together, LEF1 plays a pivotal role in the progress of HCC through transcriptional regulation of cancer stem-like cell regulator and EMT regulators. Disclosures: The following people have nothing to disclose: Jaw-Ching Wu, Chih-Li Chen, Ya-Yun Sun, Chien-Wei Su Purpose: Hepatitis C Virus (HCV) is the most common cause of hepatocellular carcinoma (HCC) in the west.

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