The gene is methylated in human hepatocellular carcinoma (Yoshida et?al
The gene is methylated in human hepatocellular carcinoma (Yoshida et?al., 2004; Yoshikawa et?al., 2001) or colorectal tumors (Fujitake et?al., 2004; Lin et?al., 2004). carcinomas. Forced expression of SOCS1 in metastatic colorectal SW620 cells reverses AC-264613 many characteristics of EpithelialCMesenchymal Transition (EMT), as highlighted by the disappearance of the transcription factor ZEB1 and the mesenchymal form of p120ctn and the re\expression of E\cadherin. Furthermore, miRNA profiling indicated that SOCS1 also up\regulates the expression of the mir\200 family of miRNAs, which can promote the mesenchymalCepithelial transition and reduce tumor cell migration. Accordingly, overexpression of SOCS1 induced cell morphology changes and dramatically reduced tumor cell invasion knockout mice (Alexander et?al., 1999) highlights the physiological importance of this protein. SOCS1 expression is usually tightly regulated by several mechanisms. SOCS1 is usually primarily regulated at the transcriptional level. Indeed, upon cytokine cell stimulation, active JAK kinases and downstream Transmission Transducers and Activators of Transcription (STAT) proteins induce the expression of genes. Besides, the SOCS1 promoter is usually actively repressed by the nuclear proteins GFI\1B (Jegalian and Wu, AC-264613 2002), Ets\1 (Travagli et?al., 2004) and Sp2 (Letourneur et?al., 2009). The gene can also be regulated by methylation of the CpG islands located in Rabbit Polyclonal to CBLN1 the translated exon 2 (Yoshikawa et?al., 2001). Stabilization of SOCS1 proteins by proteasome inhibitors suggests that cells may also regulate SOCS1 levels AC-264613 through the proteasome pathway (Zhang et?al., 1999). Expression of SOCS1 is usually often de\regulated in malignancy cells. The gene is usually methylated in human hepatocellular carcinoma (Yoshida et?al., 2004; Yoshikawa et?al., 2001) or colorectal tumors (Fujitake et?al., 2004; Lin et?al., 2004). In colon cancer, gene methylation is mainly associated with the CpG island methylator phenotype (CIMP) subclass (Shen et?al., 2007), and represents one of the nine high\rating CIMP\predicting markers (Weisenberger et?al., 2006). Besides, analysis of genetic variations in colorectal cancers indicated that single nucleotide polymorphisms (SNPs) in genes belonging to the JAK/STAT signaling pathway, including two in the gene, were associated with malignancy AC-264613 survival (Slattery et?al., 2013). Beyond being mere diagnostic/prognostic markers, genetic and epigenetic events occurring at the locus may also have a functional relevance in cancers. On one hand, several studies have characterized as a tumor suppressor gene. (Tg) mice, in which lethality conferred by the lack of SOCS1 is usually bypassed through expression of ectopic SOCS1 in T and B cells, spontaneously developed colorectal carcinomas at 6 months of age (Hanada et?al., 2006). Of notice, Tg mice treated with anti\IFN\antibody did not develop such tumors, suggesting that chronic inflammation was a critical determinant for the development of these colorectal tumors. studies with human hepatocellular carcinoma\derived cell lines indicated that restoration of SOCS1 expression leads to growth\suppressing activity (Yoshikawa et?al., 2001). Similarly, SOCS1 expression was found to be reduced in melanoma\derived tissues that experienced metastasized to the brain, as compared to the corresponding melanoma tumors (Huang et?al., 2008). Thus, these studies suggested that SOCS1 has an important, protective role in malignancy development. On the other hand, SOCS1 has been also identified as a progression marker of human melanoma. Indeed, in human melanoma, Li et?al. (2004) indicated that the level of SOCS1 protein correlates with tumor invasion and stage of diseases. Specifically, melanocytes of the normal skin or melanocytic nevi AC-264613 lack SOCS1 protein expression while melanoma cells express SOCS1 (Li et?al., 2004). The later finding suggests that the exact role of SOCS1 in tumor progression is likely to depend on the type of malignancy considered. Here we resolved the role of in colorectal malignancy (CRC). We statement that while SOCS1 is usually well expressed in CRC, its expression level decreases with the aggressiveness of the tumors. By manipulating SOCS1 levels in colorectal tumor cells, we show that this protein controls the EMT process, and the tumor cell invasiveness and metastatic potential. 2.?Material and methods 2.1. Plasmids The pcDNA3\myc\mplasmids and then cultured under 500?g/mL G418 selective conditions for at least 1 month (Travagli et?al., 2004). Two impartial clones were selected and utilized for further experiments. For transient transfection, the p4xTSV luc (GAS\reporter plasmid) (Moriggl et?al., 1996) and the pSRluc reporter (Seguin et?al., 2009) were used as previously explained (Travagli et?al., 2004). For soft agar growth assays, 2??104?cells were suspended in DMEM with 0.36% low melting agarose (Invitrogen) and 10% FCS and plated onto 1?mL/35?mm dish of DMEM with 0.6% agarose and 10% FCS. After 3 weeks, plates and individual clones were photographed and the number of colonies was decided in 3 impartial experiments. For invasion assays, cells were seeded at 2??105 per well in 24\well matrigel precoated transwell filter plates (BD BioCoat Matrigel Invasion Chambers) in serum\free.