LMP1 mRNA, expressed in latencies II and III, was present in three cases of PEL, although at very low levels that were not detectable at the protein level by immunohistochemistry.
The CD138/syndecan-1 isoform expressed by PEL has an average molecular weight of 420 kD, which is substantially different from that of CD138/syndecan-1 molecules generally expressed by plasma cells.
The PELs share several features with acquired immunodeficiency syndrome (AIDS)-associated primary central nervous system lymphomas (1 degree CNS-L), including B-cell phenotype, infection with Epstein-Barr virus, and lack of c-myc gene rearrangements.
These findings suggest that there may be an additional subcategory of primary effusion lymphoma that is not associated with HHV8 nor c-MYC(R) but is pathogenetically associated with the PAX-5 gene or hepatitis C virus.
These findings suggest that there may be an additional subcategory of primary effusion lymphoma that is not associated with HHV8 nor c-MYC(R) but is pathogenetically associated with the PAX-5 gene or hepatitis C virus.
Since BCL6 mutations are regarded as a genetic marker of B-cell transition through the germinal center (GC), these data are consistent with histogenetic derivation of PEL from GC or post-GC B-cells.
Using these mAbs, we have demonstrated that: (a) tumour cells from PEL expressed a syndecan-1 isoform with a higher molecular weight than that present on malignant plasma cells; (b) syndecan-1 expressed by PEL cells had a core protein identical in size to that expressed by plasma cells, suggesting that differences in syndecan-1 size were due to different GAG chains attached to an identical protein backbone; (c) the PEL-specific isoform of syndecan-1, which probably represented the major proteoglycan expressed by these cells, was effective in mediating cell adhesion to type I collagen substrates.
Anti-IL6 neutralizing antibodies had no effect on PEL cell line proliferation; conversely, whereas anti-IL6R alone inhibited only weakly, anti-gp130 and anti-gp130 plus anti-IL6R showed strong inhibitory effects (>20% inhibition in 5/9 lines and >60% inhibition in 3/9 lines).
In addition, we tested the response of the PEL cells to selected cytokines and the effects of neutralizing anti-cytokine and anti-cytokine receptor antibodies.
In addition, we tested the response of the PEL cells to selected cytokines and the effects of neutralizing anti-cytokine and anti-cytokine receptor antibodies.
Using specific ELISAs, PEL cell lines were found to produce large amounts of interleukin-6 (IL-6; 10-5000 pg/ml), IL-6 soluble receptor (IL-6sR; 30-600 pg/ml), IL-10 (600-80,000 pg/ml) and oncostatin M (OSM; 50-80 pg/ml) which in most cases were significantly higher than the levels produced by the Burkitt, B-NHL or myeloma cell lines; on the contrary, PEL cell lines did not elaborate significant levels of macrophage inhibitory protein (MIP-1alpha) and leukemia inhibitory factor (LIF).
To investigate whether HHV-8 may contribute to PEL development in the absence of EBV, the expression of seven potentially oncogenic HHV-8 open reading frames (ORFs) (ORF72/viral cyclin D, ORF16/viral bcl-2, ORF74/viral G-protein coupled receptor, ORFK2/viral IL-6, ORFK13/viral FLICE inhibitory protein, ORFK9/viral interferon regulatory factor, and ORFK1, equivalent to the gene encoding herpesvirus saimiri transforming protein) was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) in an EBV-negative PEL presenting in an HIV-negative patient.
To investigate whether HHV-8 may contribute to PEL development in the absence of EBV, the expression of seven potentially oncogenic HHV-8 open reading frames (ORFs) (ORF72/viral cyclin D, ORF16/viral bcl-2, ORF74/viral G-protein coupled receptor, ORFK2/viral IL-6, ORFK13/viral FLICE inhibitory protein, ORFK9/viral interferon regulatory factor, and ORFK1, equivalent to the gene encoding herpesvirus saimiri transforming protein) was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) in an EBV-negative PEL presenting in an HIV-negative patient.
To investigate whether HHV-8 may contribute to PEL development in the absence of EBV, the expression of seven potentially oncogenic HHV-8 open reading frames (ORFs) (ORF72/viral cyclin D, ORF16/viral bcl-2, ORF74/viral G-protein coupled receptor, ORFK2/viral IL-6, ORFK13/viral FLICE inhibitory protein, ORFK9/viral interferon regulatory factor, and ORFK1, equivalent to the gene encoding herpesvirus saimiri transforming protein) was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) in an EBV-negative PEL presenting in an HIV-negative patient.
Fifteen EBV positive PEL (12 AIDS-related, one post-transplant, two arising in immunocompetent hosts) were subjected to molecular characterization of the viral genes EBNA-1 and LMP-1, as well as definition of EBV type-1/type-2.
By using a combination of immunological and biological assays, production and secretion of a functional HGF species was identified in all PEL cell lines analyzed.
The Met protein expressed by PEL displays biochemical characteristics typical of Met expressed by other cell types and is capable of tyrosine autophosphorylation.
We have studied the purified KSHV-DHFR enzyme in vitro and analyzed its expression in cultured B-cell lines derived from primary effusion lymphoma (PEL), an AIDS-associated malignancy.
To clarify the pathogenesis and histogenesis of PEL by investigating (1) the lymphoma karyotype; (2) the expression status of the Met tyrosine kinase receptor and of its ligand hepatocyte growth factor (HGF); (3) the molecular profile of EBV, with particular focus on mutations of EBNA-1 genes, which are thought to affect viral tumorigenicity in EBV-infected neoplasms displaying the latency I phenotype.
To clarify the pathogenesis and histogenesis of PEL by investigating (1) the lymphoma karyotype; (2) the expression status of the Met tyrosine kinase receptor and of its ligand hepatocyte growth factor (HGF); (3) the molecular profile of EBV, with particular focus on mutations of EBNA-1 genes, which are thought to affect viral tumorigenicity in EBV-infected neoplasms displaying the latency I phenotype.
We provide evidence here that the cyclin protein is expressed in HHV8 positive primary effusion lymphoma (PEL)-derived cell lines and that its level of expression varies greatly between different lines.
Viral supernatant from JSC-1 was much more efficient at infecting primary human dermal microvascular endothelial cells (DMVECs) with KSHV than supernatants from BC-3 or BCP-1 PEL cell lines.