Altered sialidase expression in human myeloid cells undergoing apoptosis and differentiation (original) (raw)

Sialidase and malignancy: A minireview

Glycoconjugate Journal, 2000

Aberrant sialylation in cancer cells is thought to be a characteristic feature associated with malignant properties including invasiveness and metastatic potential. Sialidase which catalyzes the removal of sialic acid residues from glycoproteins and glycolipids, has been suggested to play important roles in many biological processes through regulation of cellular sialic acid contents. The altered expression of sialidase observed in cancer would, therefore, suggest its involvement in the malignant process. In mammalian cells, three types of sialidase cloned and characterized to date were found to behave in different manners during carcinogenesis. Recent progress in molecular cloning of these sialidases has facilitated elucidation of the molecular mechanisms and significance of these alterations. Herein we briefly describe our own studies on sialidase changes associated with malignant transformation and summarize the topic from both a retrospective and a prospective viewpoint. Sialidases are indeed closely related to malignancy and are thus potential targets for cancer diagnosis and therapy.

Sialidase significance for cancer progression

Glycoconjugate Journal, 2012

Aberrant glycosylation is a characteristic feature of cancer cells. In particular, altered sialylation is closely associated with malignant properties, including invasiveness and metastatic potential. To elucidate the molecular mechanisms underlying the aberrancy, our studies have focused on mammalian sialidase, which catalyzes the removal of sialic acid residues from glycoproteins and glycolipids. The four types of mammalian sialidase identified to date show altered expression and behave in different manners during carcinogenesis. The present review briefly summarizes results on altered expression of sialidases and their possible roles in cancer progression. These enzymes are indeed factors defining cancer malignancy and thus potential targets for cancer diagnosis and therapy.

Sweet kiss of dying cell: Sialidase activity on apoptotic cell is able to act toward its neighbors

Autoimmunity, 2012

Apoptotic cells and subcellular microparticles expose increased sialidase activity on their surfaces, which results from caspase-3 dependent activation of plasma membrane associated Neuraminidase-1 (Neu1). Desialylation of dying cells is also known to promote efferocytosis. The intriguing question remained whether sialidase on the surface of dying cell merely acts on self targets (cis-action), or whether it can also cleave glycoepitopes of neighboring cells (trans-action). Here, we co-incubated human viable and apoptotic Jurkat lymphocytes or neutrophils with human erythrocytes and evaluated their glycoprofile for terminal sialic acids by agglutination assay, flow cytometry, ELISA and dot-blot analyses. Data suggest that erythrocytes were desialylated as soon as 3 hours after co-incubation with apoptotic cells, but not with viable ones. After co-incubation of L929 murine fibroblasts with viable or apoptotic murine L1210 cells the L929 cells gained a desialylated glycoprofile, only after co-incubation with apoptotic cells. Our data suggests that activated sialidase(s) on the surfaces of apoptotic cells are capable to desialylate neighboring cells in trans.

Transcriptional control of mammalian sialidase genes

International Congress Series, 2001

Sialidase catalyzes the release of sialic acid from glycoproteins and glycolipids, which is an initial step in the degradation of these molecules. Sialidases of mammalian origin have been implicated not only in lysosomal catabolism but also in the modulation of functional molecules involved in many biological processes. However, the regulation mechanism of desialylation remains obscure because the structure and function of mammalian sialidase genes are not fully understood. Recently, three types of mammalian sialidase have been isolated, and the cDNAs enabled us to elucidate the desialylation mechanism at a molecular level. We previously cloned rat cytosolic sialidase gene and demonstrated that the gene is highly expressed in skeletal muscle, contains TATA box and E-box, known as a target sequence of myogenic transcription factors, in its promoter region, and is, in fact, involved in muscle cell differentiation. We next were able to clone a human membrane sialidase and found that the gene is highly expressed in the skeletal muscle and testis and is up-regulated in various human tumors. Unlike the cytosolic sialidase gene, the membrane gene contains neither TATA box nor E-box in its 5 0 flanking region, suggesting that transcription of these two genes is differently regulated in the skeletal muscle. D