The Multicenter, Randomized, Phase 2 PEACE V-STORM Trial: Defining the Best Salvage Treatment for Oligorecurrent Nodal Prostate Cancer Metastases.

Optimal local treatment for nodal oligorecurrent prostate cancer is unknown. The randomized phase 2 PEACE V-STORM trial will explore the best treatment approach in this setting. Early results on the acute toxicity profile are projected to be published in quarter 3, 2021.

The Yaa mutation promoting murine lupus causes defective development of marginal zone B cells.

The accelerated development of systemic lupus erythematosus (SLE) in BXSB male mice is associated with the presence of an as yet unidentified mutant gene, Yaa (Y-linked autoimmune acceleration). In view of a possible role of marginal zone (MZ) B cells in murine SLE, we have explored whether the expression of the Yaa mutation affects the differentiation of MZ and follicular B cells, thereby implicating the acceleration of the disease. In this study, we show that both BXSB and C57BL/6 Yaa mice, including two different substrains of BXSB Yaa males that are protected from SLE, displayed an impaired development of MZ B cells early in life. Studies in bone marrow chimeras revealed that the loss of MZ B cells resulted from a defect intrinsic to B cells expressing the Yaa mutation. The lack of selective expansion of MZ B cells in diseased BXSB Yaa males strongly argues against a major role of MZ B cells in the generation of pathogenic autoantibodies in the BXSB model of SLE. Furthermore, a comparative analysis with mice deficient in CD22 or expressing an IgM anti-trinitrophenyl/DNA transgene suggests that the hyperreactive phenotype of Yaa B cells, as judged by a markedly increased spontaneous IgM secretion, is likely to contribute to the enhanced maturation toward follicular B cells and the block in the MZ B cell generation.

Anti-CD20 therapeutic antibody rituximab modifies the functional organization of rafts/microdomains of B lymphoma cells.

Incubation of Burkitt lymphoma-derived Raji cells at physiological temperature with submicromolar concentrations of humanized anti-CD20 antibody rituximab (RTX) redistributes CD20 to liquid-ordered, plasma membrane rafts. This accumulation of the CD20 tetraspan protein in rafts does not change the existing lipid and phosphoprotein composition but makes sphingolipids and the Src regulator Cbp/PAG (Csk-binding protein/phosphoprotein associated with glycosphingolipid-enriched microdomain) transmembrane phosphoprotein more resistant to n-octyl-beta-pyranoside, a detergent that dissociates sphingolipid clusters. On the contrary, sphingolipids and Cbp/PAG are not protected by the presence of CD20 against the disruptive effects of methyl-beta-cyclodextrin, a cyclic carbohydrate that removes membrane cholesterol. After accumulation of CD20, the activity of the raft-associated Lyn kinase is down-regulated without apparent alteration of its relationship to substrates. Moreover, in rafts of lymphoblastoid cells that express lower amounts of Cbp/PAG, RTX redistributes CD20 to rafts but does not modulate the raft-associated protein tyrosine kinase activity, suggesting that the presence of Cbp/PAG protein in rafts is necessary for RTX to exert its transmembrane "signaling effects." Lastly, redistribution of CD20 in rafts renders the glycosylphosphatidyl inositol (GPI)-linked CD55 C'-defense protein hypersensitive to glycosylphosphatidyl inositol-specific phospholipases. By redistributing CD20 to rafts, RTX modifies their stability and organization and modulates the associated signaling pathways and C' defense capacity.

Differentially regulated expression and function of CD22 in activated B-1 and B-2 lymphocytes.

CD22 is a B cell-restricted transmembrane protein that apparently controls signal transduction thresholds initiated through the B cell Ag receptor (BCR) in response to Ag. However, it is still poorly understood how the expression of CD22 is regulated in B cells after their activation. Here we show that the expression levels of CD22 in conventional B-2 cells are markedly down-regulated after cross-linking of BCR with anti-IgM mAb but are up-regulated after stimulation with LPS, anti-CD40 mAb, or IL-4. In contrast, treatment with anti-IgM mAb barely modulated the expression levels of CD22 in CD5(+) B-1 cells, consistent with a weak Ca(2+) response in anti-IgM-treated CD5(+) B-1 cells. Moreover, in CD22-deficient mice, anti-IgM treatment did not trigger enhanced Ca(2+) influx in CD5(+) B-1 cells, unlike CD22-deficient splenic B-2 cells, suggesting a relatively limited role of CD22 in BCR signaling in B-1 cells. In contrast, CD22 levels were markedly down-regulated on wild-type B-1 cells in response to LPS or unmethylated CpG-containing oligodeoxynucleotides. These data indicate that the expression and function of CD22 are differentially regulated in B-1 and conventional B-2 cells, which are apparently implicated in innate and adaptive immunity, respectively.