Altered Gene Expression upon BCR Cross-Linking in Burkitt's Lymphoma B Cell Line

Nakayama, Yasuhiro; Iwamoto, Yoshiki; Maher, Stephen E.; Tanaka, Yujiro; Bothwell, Alfred L.M.

doi:10.1006/bbrc.2000.3639

Cited by 8 publications

(8 citation statements)

References 28 publications

(22 reference statements)

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“…Expression of transforming v-src in fibroblasts down-regulates SIRP␣, whereas overexpression of SIRP␣ reduces anchorage-independent cell growth (45). Although SIRP␣ is not normally expressed on B cells, representational difference analysis of a Burkitt's lymphoma B-cell line has demonstrated up-regulation of SIRP␣ on immunoglobulin cross-linking (46). Recent reports have also shown reduced expression of SIRP␣ in breast cancer relative to paired normal breast tissues, as examined by Western blotting, although the cell types that expressed SIRP␣ were not identified (47).…”

Section: Introductionmentioning

confidence: 99%

Expression and Activation of Signal Regulatory Protein α on Astrocytomas

Chen

Brown²,

Huang³

et al. 2004

Cancer Research

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High-grade astrocytomas and glioblastomas are usually unresectable because they extensively invade surrounding brain tissue. Here, we report the expression and function of a receptor on many astrocytomas that may alter both the proliferative and invasive potential of these tumors. Signal regulatory protein (SIRP) ␣1 is an immunoglobulin superfamily transmembrane glycoprotein that is normally expressed in subsets of myeloid and neuronal cells. Transfection of many cell types with SIRP␣1, including glioblastomas, has been shown to inhibit their proliferation in response to a range of growth factors. Furthermore, the expression of a murine SIRP␣1 mutant has been shown to enhance cell adhesion and initial cell spreading but to inhibit cell extension and movement. The extracellular portion of SIRP␣1 binds CD47 (integrin-associated protein), although this interaction is not required for integrin-mediated activation of SIRP␣1. On phosphorylation, SIRP␣1 recruits the tyrosine phosphatases SHP-1 and SHP-2, which are important in its functions. Although SHP-1 is uniquely expressed on hematopoietic cells, SHP-2 is ubiquitously expressed, so that SIRP␣1 has the potential to function in many cell types, including astrocytomas. Because SIRP␣1 regulates cell functions that may contribute to the malignancy of these tumors, we examined the expression of SIRPs in astrocytoma cell lines by flow cytometry using a monoclonal antibody against all SIRPs. Screening of nine cell lines revealed clear cell surface expression of SIRPs on five cell lines, whereas Northern blotting for SIRP␣ transcripts showed mRNA present in eight of nine cell lines. All nine cell lines expressed the ligand for SIRP␣1, CD47. To further examine the expression and function of SIRPs, we studied the SF126 and U373MG astrocytoma cell lines, both of which express SIRPs, in greater detail. SIRP transcripts in these cells are identical in sequence to SIRP␣1. The expressed deglycosylated protein is the same size as SIRP␣1, but in the astrocytoma cells, it is underglycosylated compared with SIRP␣1 produced in transfected Chinese hamster ovary cells. It is nonetheless still capable of binding soluble CD47. Moreover, SIRP␣1 in each of the two cell lines recruited SHP-2 on phosphorylation, and SIRP␣1 phosphorylation in cultured cells is CD47 dependent. Finally, examination of frozen sections from 10 primary brain tumor biopsies by immunohistochemistry revealed expression of SIRPs on seven of the specimens, some of which expressed high levels of SIRPs. Most of the tumors also expressed CD47. This is the first demonstration that astrocytomas can express SIRP␣. Given the known role of SIRP␣ in regulating cell adhesion and responses to mitogenic growth factors, the expression of SIRP␣1 on astrocytomas may be of considerable importance in brain tumor biology, and it offers the potential of a new avenue for therapeutic intervention.

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Section: Introductionmentioning

confidence: 99%

Expression and Activation of Signal Regulatory Protein α on Astrocytomas

Chen

Brown²,

Huang³

et al. 2004

Cancer Research

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“…47,48 Over-expression of LCP2 has been detected in a Burkitt's lymphoma B cell line after B cell receptor cross-linking, and the protein may have a role in B cell receptor signaling as well. 48,49 Interestingly, LCP2 was also found to be over-expressed in CLL by the cDNA array method. 26 No involvement of the gene in ALL has been reported so far.…”

Section: Discussionmentioning

confidence: 99%

Expression of myeloid-specific genes in childhood acute lymphoblastic leukemia – a cDNA array study

et al. 2002

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Several specific cytogenetic changes are known to be associated with childhood acute lymphoblastic leukemia (ALL), and many of them are important prognostic factors for the disease. Little is known, however, about the changes in gene expression in ALL. Recently, the development of cDNA array technology has enabled the study of expression of hundreds to thousands of genes in a single experiment. We used the cDNA array method to study the gene expression profiles of 17 children with precursor-B ALL. Normal B cells from adenoids were used as reference material. We discuss the 25 genes that were most over-expressed compared to the reference. These included four genes that are normally expressed only in the myeloid lineages of the hematopoietic cells: RNASE2, GCSFR, PRTN3 and CLC. We also detected over-expression of S100A12, expressed in nerve cells but also in myeloid cells. In addition to the myeloid-specific genes, other over-expressed genes included AML1, LCP2 and FGF6. In conclusion, our study revealed novel information about gene expression in childhood ALL. The data obtained may contribute to further studies of the pathogenesis and prognosis of childhood ALL.

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“…Cells were maintained in RPMI 1640 medium supplemented with 10% FBS. Activation of BL-2, CL-01 or Ramos with anti-IgM treatment was performed as previously described (11). immortalized human microvascular endothelial cell line) were available from our laboratories stocks.…”

Section: Methodsmentioning

confidence: 99%

“…The original cDNA fragment was a 756 bp DNA fragment isolated by RDA (11) with the Accession No. AW755261.…”

Section: Methodsmentioning

confidence: 99%

BXMAS1 Identifies a Cluster of Homologous Genes Differentially Expressed in B Cells

Nakayama

Weissman

Bothwell

2001

Biochemical and Biophysical Research Communications

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Altered Gene Expression upon BCR Cross-Linking in Burkitt's Lymphoma B Cell Line

Cited by 8 publications

References 28 publications

Expression and Activation of Signal Regulatory Protein α on Astrocytomas

Expression and Activation of Signal Regulatory Protein α on Astrocytomas

Expression of myeloid-specific genes in childhood acute lymphoblastic leukemia – a cDNA array study

BXMAS1 Identifies a Cluster of Homologous Genes Differentially Expressed in B Cells

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