Expression and function of a receptor for hyaluronan-mediated motility on normal and malignant B lymphocytes

Abstract

Migration through extracellular matrix is fundamental to malignant invasion. A receptor for hyaluronan-mediated motility (RHAMM) has previously been shown to play a fundamental role in locomotion of ras- transformed cells as well as functioning in signal transduction. Expression of RHAMM was characterized on B lymphocytes from normal and malignant lymphoid tissues using multiparameter phenotypic immunofluorescence analysis as well as functional analysis of its role in locomotion of malignant hairy cell leukemia B cells. RHAMM is not detectable on most normal B cells located in blood, spleen, or lymph node, but it is detectable on bone marrow and thymic B cells. Among B- cell malignancies, it is expressed on most terminally differentiated B cells from multiple myeloma bone marrows, is present on a subset of non- Hodgkin's lymphomas, and is absent on B chronic lymphocytic leukemia. Activation of peripheral blood B cells by Staphylococcus A cowan (SAC), but not by pokeweed mitogen, induced transient expression of RHAMM at day 3 of culture, suggesting RHAMM may be used by antigen-activated normal B cells. For malignant cells, expression of RHAMM increased on long-term culture of bone marrow plasma cells from multiple myeloma patients, indicating prolonged expression in contrast to the transient expression on SAC-activated normal B cells. Intriguingly, RHAMM was expressed on hairy leukemia cells located in spleen but absent from those in peripheral blood of the same patient. RHAMM, as expressed on splenic hairy cells, was a 58-Kd molecule that binds hyaluronan, is encoded by a 5.2-kb messenger RNA, and participates in locomotion by these cells. Hairy cells locomoted in response to hyaluronan at 4 mu per minute. Monoclonal antibody to RHAMM inhibited this locomotion almost completely as detected using video time-lapse cinemicrography. These observations are consistent with a role for RHAMM in malignant invasion and metastatic growth.

Differential modulation of the immune response by breast‐ or formula‐feeding of infants

“…VLA-5) and the expressed a401 integrin, while for formula-fed children, 7 5 4 0 % expressed a high density of a 4 p l and 40-50% expressed a661 (29). This apparent activation of B cells was confirmed by the expression of RHAMM, a receptor for hyaluronan-mediated motility, absent from normal B cells (20,21) but readily detectable on 30-50% of B cells from formula-fed children. Thus based on several measures, unlike PBMC from breastfed children, T and B cells from children fed formula appear to circulate in a chronically activated state.…”

Beta1‐Integrins Control Spontaneous Adhesion and Motility of Human Progenitor Thymocytes and Regulate Differentiation‐Dependent Expression of the Receptor for Hyaluronan‐Mediated Motility

“…5). MN Thy were cultured for 3 days on wells coated with MoAbs to ␤ 1 -, ␣ 4 -or ␣ 5 -integrins followed by extraction of RNA and detection of RHAMM-specific mRNA using a RHAMM cDNA probe [36]. The inhibition of RHAMM-specific mRNA by all three MoAbs confirmed that the absence or reduction of staining for surface RHAMM reflected an inhibition of mRNA expression and thus a genuine loss of RHAMM from the cell surface.…”

“…Northern analysis of mRNA. RNA extraction, Northern analysis and dot-blots were carried out as previously described [34][35][36], and blots were probed with RHAMM cDNA [16,36].…”

Multidrug transporter p‐glycoprotein 170 as a differentiation antigen on normal human lymphocytes and thymocytes: Modulation with differentiation stage and during aging

“…Cord blood was taken at delivery. Solid tissues were minced and passed through a sieve to disperse cells followed by purification on Ficoll-Paque (Pharmacia, Dorval, Quebec, Canada) [41,42]. Lymphoid cells from bone marrow were flushed from the bone using a syringe to force medium through the bone matrix.…”