Rabbit Anti-Human RAF1 (Phospho-Ser289) polyclonal antibody

Presence of tumor-derived cell-free miRNA in biological fluids as well as simplicity and robustness of cell-free miRNA quantification makes them suitable markers for cancer diagnostics. Based on previously published data demonstrating diagnostic potentialities of miR-205 in blood and miR-19b as well as miR-125b in urine of prostate cancer patients, bioinformatics analysis was carried out to follow their involvement in prostate cancer development and select additional miRNA-markers for prostate cancer diagnostics. Studied miRNAs are involved in different signaling pathways and regulate a number of genes involved in cancer development. Five of their targets (CCND1, BRAF, CCNE1, CCNE2, RAF1), according to the STRING database, act as part of the same signaling pathway. RAF1 is regulated by miR-19b and miR-125b, and it was shown to be involved in prostate cancer development by DIANA and STRING databases. Thus, other microRNAs regulating RAF1 expression such as miR-16, -195, -497, and -7 (suggested by DIANA, TargetScan, MiRTarBase and miRDB databases) can potentially be regarded as prostate cancer markers.

Long non-coding RNAs (ncRNAs) are major regulators of gene expression and cell fate. TheINK4locus encodes the tumour suppressor proteins p15(INK4b), p16(INK4a)and p14(ARF)required for cell cycle arrest and whose expression increases during senescence.ANRILis a ncRNA antisense to thep15gene. In proliferative cells,ANRILprevents senescence by repressingINK4genes through the recruitment of Polycomb-group proteins. In models of replicative and RASval12 oncogene-induced senescence (OIS), the expression ofANRILand Polycomb proteins decreases, thus allowingINK4derepression. Here, we found in a model of RAF1 OIS thatANRILexpression rather increases, due in particular to an increased stability. This led us to search for circularANRILisoforms, as circular RNAs are rather stable species. We found that the expression of two circularANRILincreases in several OIS models (RAF1, MEK1 and BRAF). In proliferative cells, they repressp15expression, while in RAF1 OIS, they promote full induction ofp15, p16andp14(ARF)expression. Further analysis of one of these circularANRILshows that it interacts with Polycomb proteins and decreases EZH2 Polycomb protein localization and H3K27me3 at thep15andp16promoters, respectively. We propose that changes in the ratio between Polycomb proteins and circularANRILisoforms allow these isoforms to switch from repressors ofp15gene to activators of allINK4genes in RAF1 OIS. Our data reveal that regulation ofANRILexpression depends on the senescence inducer and underline the importance of circularANRILin the regulation ofINK4gene expression and senescence.