ANLN

Abstract: We report the cDNA sequence and localization of a protein first identified by actin filament chromatography of Drosophila embryo extracts as ABP8 (Miller, K. G., C. M. Field, and B. M. Alberts. 1989. J. Cell Biol. 109:2963-2975). The cDNA encodes a 1201-amino acid protein which we name anillin. Anillin migrates at 190 kD on SDS-PAGE. Anillin is expressed throughout Drosophila development and in tissue culture cells. By immunofluorescence, anillin localizes to the nucleus of interphase cells, except in the syncytial embryo where it is always cytoplasmic. During metaphase, it is present in the cytoplasm and cortex, and during anaphase-telophase it becomes highly enriched in the cleavage furrow along with myosin II. In the syncytial embryo, anillin, along with myosin-II, is enriched in cortical areas undergoing cell cycle regulated invagination including metaphase furrows and the cellularization front. In contractile rings, metaphase furrows, and nascent ring canals, anillin remains bound to the invaginated cortex suggesting a stabilizing role. Anillin is not expressed in cells that have left the cell cycle. Anillin isolated from embryo extracts binds directly to actin filaments. The domain responsible for this binding has been mapped to a region of 244 amino acids by expression of protein fragments in bacteria. This domain, which is monomeric in solution, also bundles actin filaments. We speculate that anillin plays a role in organizing and/or stabilizing the cleavage furrow and other cell cycle regulated, contractile domains of the actin cytoskeleton.

Abstract: We demonstrate that the contractile ring protein anillin interacts directly with nonmuscle myosin II and that this interaction is regulated by myosin light chain phosphorylation. We show that despite their interaction, anillin and myosin II are independently targeted to the contractile ring. Depletion of anillin in Drosophila or human cultured cells results in cytokinesis failure. Human cells depleted for anillin fail to properly regulate contraction by myosin II late in cytokinesis and fail in abscission. We propose a role for anillin in spatially regulating the contractile activity of myosin II during cytokinesis.

Abstract: Pancreatic cancer is a highly lethal malignancy with poor prognosis. Anillin (ANLN), an actin binding protein, is upregulated and plays an important role in many malignant tumors. However, the precise role of ANLN in pancreatic cancer remains unclear. The expression of ANLN and its association with pancreatic cancer patient survival were analyzed using an online database and confirmed by immunohistochemistry. The ANLN protein expression in pancreatic cancer cell lines was detected by Western blot. Cell proliferation, colony formation and transwell assays in vitro and in vivo tumor growth were used to determine the role of ANLN in pancreatic cancer. Gene expression microarray analysis and a series of in vitro assays were used to elucidate the mechanisms of ANLN regulating pancreatic cancer progression. We found that the ANLN expression was significantly upregulated in pancreatic cancer tissues and cell lines. The high expression of ANLN was associated with tumor size, tumor differentiation, TNM stage, lymph node metastasis, distant metastasis and poor prognosis in pancreatic cancer. ANLN downregulation significantly inhibited cell proliferation, colony formation, migration, invasion and tumorigenicity in nude mice. Meanwhile, we found that ANLN knockdown inhibited several cell-cell adhesion related genes, including the gene encoding LIM and SH3 protein 1 (LASP1). LASP1 upregulation partially reversed the tumor-suppressive effect of ANLN downregulation on pancreatic cancer cell progression. Moreover, we found that ANLN downregulation induced the expression of miR-218-5p which inhibited LASP1 expression through binding to its 3’UTR. We also found that ANLN-induced enhancer of zeste homolog 2 (EZH2) upregulation was involved in regulating miR-218-5p/LASP1 signaling axis. EZH2 upregulation or miR-218-5p downregulation partially reversed the tumor-suppressive effect of ANLN downregulation on pancreatic cancer cell progression. ANLN contributed to pancreatic cancer progression by regulating EZH2/miR-218-5p/LASP1 signaling axis. These findings suggest that ANLN may be a candidate therapeutic target in pancreatic cancer.