Disease relevance of CD44

• These granulomas also had many major histocompatibility class II+ cells and CD11c+ dendritic cells, and cells expressing CD18 and CD44 [1].
• CD44 was present within benign and malignant melanomas, but its expression was more intense in malignant melanomas (P < 0.01) [2].
• The observed aberrant fucosylation of these proteins is consistent with the hypothesis that CD44 and E-selectin play a key role in metastasis and the spread of cancer cells to remote sites [3].
• Up-regulation of the hyaluronate receptor CD44 in canine distemper demyelinated plaques [4].
• As astrocytes are the main target cell of canine distemper virus (CDV), the consequences of a CDV infection on the CD44 expression and distribution in brains with spontaneous demyelinating canine distemper encephalitis (CDE) were of interest [4].

High impact information on CD44

• The NF2 tumor suppressor gene product, merlin, mediates contact inhibition of growth through interactions with CD44 [5].
• These data indicate that merlin and CD44 form a molecular switch that specifies cell growth arrest or proliferation [5].
• An antibody to CD44 enhances hematopoiesis in long-term marrow cultures [6].
• Monoclonal antibody S5, which is specific for CD44, facilitates engraftment of major histocompatibility complex (MHC)-mismatched canine bone marrow (BM) when infused into recipient animals before total body irradiation (TBI) and marrow infusion [6].
• In summary, CD44 is up-regulated on astrocytes in the early phase of CDE and seems to represent a marker for the activation of immune cells in the late phase of the infection [4].

Biological context of CD44

• Using PCR with primers complementary to regions contiguous to the insertion point and a variant exon, all ten variant exons of dog CD44 were detected in a high number of different isoforms [7].
• CD44, the main cell surface receptor for hyaluronan (HA), is often overexpressed in tumour cells, and its presence has been related to cell proliferation and migration [2].
• Two of the proteins identified, CD44 and E-selectin, are known to be involved in cell adhesion and cancer cell migration [3].

Anatomical context of CD44

• Expression of CD44 variant transcripts in dog lymphatic tissue [7].
• Both canine melanoma cell lines expressed CD44 and produced HA, but only CML-1 produced versican [2].
• Microglia and monocytes can be clearly distinguished by their differential expression intensity of surface antigens (CD45, CD44, CD14) [8].
• Cells expressing all three components (CD44, HA and versican) formed abundant extracellular matrices as demonstrated by a particle exclusion assay [2].
• The association of high molecular mass (M(r)) HA with cell surface receptors such as CD44 gives rise to pericellular matrix (PCM) formation by many eukaryotic cells in culture [9].

Associations of CD44 with chemical compounds

• The gene of the CD44 cell surface glycoprotein consists of 20 exons [7].
• The expression of CD44 and HA was studied using fluorescent probes, and crystal binding was quantified with radiolabeled calcium oxalate monohydrate [9].

Analytical, diagnostic and therapeutic context of CD44

• Molecular cloning of the dog homologue of the human CD44 was achieved using RT/PCR [10].
• Molecular cloning of the canine CD44 antigen cDNA [10].
• Conversely, immunoblotting demonstrated the content of non-muscle myosin heavy chain, l-caldesmon, vimentin, alpha/beta-protein kinase C (PKC), and CD44 homing cellular adhesion molecule (HCAM) increased one- to sixfold as cells became proliferative [11].
• For immunoelectron microscopy, 90-nm-thick sections were double stained with anti-GFAP and anti-CD44 mAbs to specify CD44-expressing structures [4].
• Ligation of CD44 in the early phase may induce chemokines and cytokines and hence initiate and perpetuate the inflammatory process [12].

References