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Query: UMLS:C0079731 (B-cell lymphoma)
 16,671 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this research was to determine whether prostaglandin E2 (PGE2), a major product of macrophages which can kill certain murine B cell lymphomas, induces death by a necrotic mechanism or by an alternate pathway called apoptosis. CH31 is a phenotypically "immature" B cell lymphoma which resembles immature neonatal B cells in its susceptibility to killing by reagents which cross-link surface immunoglobulin (sIg). In the present study we first show that PGE2, but not the closely related prostanoid, PGF2 alpha, kills CH31 lymphoma cells. In contrast, CH12, a phenotypically "mature" lymphoma which is not negatively affected by sIg cross-linking, is not induced to die after exposure to PGE2. Agarose gel electrophoresis demonstrated that the DNA of PGE2-treated CH31, but not CH12 cells, is cleaved into characteristic 200 base pair oligonucleosomal fragments indicative of an apoptotic mechanism of death. However, a necrotic form of death, indicated by random DNA cleavage which produces a smear following electrophoresis, could be induced by treatment of CH12 or CH31 with anti-class II MHC antibodies and complement. The apoptotic mechanism of CH31 cell killing by PGE2 was confirmed using scanning electron microscopy which demonstrated the unique membrane blebbing and bubbling pathognomonic of this form of death. Finally, using a recently devised flow cytometric method to study apoptosis in heterogeneous cell populations, we compared the ability of anti-IgM, PGE2, or PGF2 alpha to induce apoptosis in B lymphocytes from neonatal or adult mice. Anti-IgM, and to a lesser extent PGE2, but not PGF2 alpha, induces apoptosis in a fraction of neonatal B cells. None of these treatments induced cell death in B lymphocytes from mature mice. Overall, these observations suggest that PGE-secreting cells such as macrophages, which inhabit the B cell microenvironments of lymphoid organs, may eliminate a subset of immature B lymphocytes and may be important in controlling the spread of PGE-sensitive malignant B lymphoma cells.
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PMID:Prostaglandin E2 induces apoptosis in immature normal and malignant B lymphocytes. 162 42

The physiological functions of human TCRVgamma9Vdelta2(+) gammadelta lymphocytes reactive to non-peptide phosphoantigens contribute to cancer immunosurveillance and immunotherapy. However, their regulation by mesenchymal stem cells (MSC), multipotent and immunomodulatory progenitor cells able to infiltrate tumors, has not been investigated so far. By analyzing freshly isolated TCRVgamma9Vdelta2(+) lymphocytes and primary cell lines stimulated with synthetic phosphoantigen or B-cell lymphoma cell lines in the presence of MSC, we demonstrated that MSC were potent suppressors of gammadelta-cell proliferation, cytokine production and cytolytic responses in vitro. This inhibition was mediated by the COX-2-dependent production of prostaglandin E2 (PGE(2)) and by MSC through EP2 and EP4 inhibitory receptors expressed by Vgamma9Vdelta2 T lymphocytes. COX-2 expression and PGE(2) production by MSC were not constitutive, but were induced by IFN-gamma and TNF-alpha secreted by activated Vgamma9Vdelta2 T cells. This regulatory cross-talk between MSC and Vgamma9Vdelta2 T lymphocytes involving PGE(2) could be of importance for the antitumor and antimicrobial activities of gammadelta T cells.
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PMID:A regulatory cross-talk between Vgamma9Vdelta2 T lymphocytes and mesenchymal stem cells. 1919 41

Previous clinicopathological studies demonstrated that overexpression of cyclooxygenase-2 (COX-2) is associated with a poor treatment response of esophageal carcinoma. The aim of this study was to elucidate the role of COX-2 overexpression in the chemosensitivity of esophageal carcinoma cells. TE13 human esophageal squamous cell carcinoma cells were transfected with a COX-2 constitutive expression vector, and stable transfectants overexpressing COX-2 were established. COX-2 overexpression in COX-2 transfectants was confirmed with western blotting and prostaglandin-E(2) (PGE(2)) assay. Chemosensitivity testing revealed that sensitivity of COX-2 transfectants to 5-fluorouracil and cisplatin was significantly lower than in control vector-only transfectants, and that sensitivity of COX-2 transfectants was restored by the transfection of COX-2-specific siRNA. In addition, expression of antiapoptotic B-cell lymphoma-extra large (BCL-xL) and myeloid cell leukaemia-1 (MCL-1) was increased in COX-2 transfectants. These results indicate that COX-2 overexpression may reduce the chemosensitivity of esophageal carcinoma cells through up-regulation of the expression of antiapoptotic BCL-2 family proteins.
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PMID:COX-2 overexpression Induced by gene transfer reduces sensitivity of TE13 esophageal carcinoma cells to 5-fluorouracil and cisplatin. 2339 46