The Importance of Applying ACOSOG Z0011 Criteria in the Axillary Management of Invasive Lobular Carcinoma: A Multi-institutional Cohort Study.

BACKGROUND: The American College of Surgeons Oncology Group (ACOSOG) Z0011 trial led to a significant change in the management of patients with early stage breast cancer and limited sentinel lymph node (SLN) metastases. However, only 27 patients with invasive lobular carcinoma (ILC) were randomized to the completion axillary lymph node dissection (ALND) arm. To assess the generalizability of the Z0011 trial, the primary aim of this study was to determine the risk of residual nodal burden (RNB) for ILC. METHODS: A multi-institutional cohort study was completed. RNB was determined for women of any age with an ILC and at least one positive SLN who underwent a primary breast procedure (lumpectomy or mastectomy) and both a SLN biopsy followed by a completion ALND between July 1, 1999, and June 30, 2009, at two large academic centers. RESULTS: A total of 59 patients (60 ILCs) met the inclusion criteria. Although the overall RNB was 40%, it was significantly greater in the T3+ group compared to T1/T2 (87 vs. 24%, respectively, p < 0.0001). When comparing only ILCs that met all of the inclusion criteria for ACOSOG Z0011 (T1 or T2, 1 or 2 SLNs positive, no SLN extranodal extension, and breast conservation) to those ILCs that did not, the RNB was significantly greater in the latter (56 vs. 17 %; p < 0.003). CONCLUSIONS: Overall, the clinical practice changes that have occurred after publication of the ACOSOG Z0011 trial appear to be generalizable to ILCs within the inclusion criteria of the study.

Verotoxin A subunit protects lymphocytes and T cell lines against X4 HIV infection in vitro.

Our previous genetic, pharmacological and analogue protection studies identified the glycosphingolipid, Gb(3) (globotriaosylceramide, Pk blood group antigen) as a natural resistance factor for HIV infection. Gb(3) is a B cell marker (CD77), but a fraction of activated peripheral blood mononuclear cells (PBMCs) can also express Gb(3). Activated PBMCs predominantly comprise CD4+ T-cells, the primary HIV infection target. Gb(3) is the sole receptor for Escherichia coli verotoxins (VTs, Shiga toxins). VT1 contains a ribosome inactivating A subunit (VT1A) non-covalently associated with five smaller receptor-binding B subunits. The effect of VT on PHA/IL2-activated PBMC HIV susceptibility was determined. Following VT1 (or VT2) PBMC treatment during IL2/PHA activation, the small Gb(3)+/CD4+ T-cell subset was eliminated but, surprisingly, remaining CD4+ T-cell HIV-1(IIIB) (and HIV-1(Ba-L)) susceptibility was significantly reduced. The Gb(3)-Jurkat T-cell line was similarly protected by brief VT exposure prior to HIV-1(IIIB) infection. The efficacy of the VT1A subunit alone confirmed receptor independent protection. VT1 showed no binding or obvious Jurkat cell/PBMC effect. Protective VT1 concentrations reduced PBMC (but not Jurkat cell) proliferation by 50%. This may relate to the mechanism of action since HIV replication requires primary T-cell proliferation. Microarray analysis of VT1A-treated PBMCs indicated up regulation of 30 genes. Three of the top four were histone genes, suggesting HIV protection via reduced gene activation. VT blocked HDAC inhibitor enhancement of HIV infection, consistent with a histone-mediated mechanism. We speculate that VT1A may provide a benign approach to reduction of (X4 or R5) HIV cell susceptibility.

A synthetic globotriaosylceramide analogue inhibits HIV-1 infection in vitro by two mechanisms.

Previously, it was shown that the cell-membrane-expressed glycosphingolipid, globotriaosylceramide (Gb(3)/P(k)/CD77), protects against HIV-1 infection and may be a newly described natural resistance factor against HIV infection. We have now investigated the potential of a novel, water soluble, non-toxic and completely synthetic analogue of Gb(3)/P(k) (FSL-Gb(3)) to inhibit HIV-1 infection in vitro. A uniquely designed analogue, FSL-Gb(3), of the natural Gb(3)/P(k) molecule was synthesized. HIV-1(IIIB) (X4 virus) and HIV-1(Ba-L) (R5 virus) infection of PHA/interleukin-2-activated, peripheral blood mononuclear cells (PBMCs) and Jurkat T cells in vitro was assessed, as well as infection of U87.CD4.CCR5 by various clinical R5 tropic viruses after treatment with FSL-Gb(3). We monitored Gb(3), CD4 and CXCR4 expression by fluorescent antibody cell sorting and viral replication by p24(gag) ELISA. Total cellular Gb(3) was examined by glycosphingolipid extraction and thin layer chromatography. In vivo toxicity was monitored in mice by histological assessment of vital organs and lymphoid tissue. FSL-Gb(3) blocked X4 and R5 of both lab and clinical viral strains in activated PBMCs or the U87.CD4.CCR5 cell line with a 50% inhibitory concentration (IC(50)) of approximately 200-250 microM. FACS and TLC overlay showed that FSL-Gb(3) can insert itself into cellular plasma membranes and that cellular membrane-absorbed FSL-Gb(3) is able to inhibit subsequent HIV-1 infection. There was no effect of FSL-Gb(3) on cell surface levels of CD4 or CXCR4. Thus, FSL-Gb(3) can inhibit HIV-1 by two mechanisms: direct inhibition of virus and inhibition of viral entry. Infusion of FSL-Gb(3) into laboratory mice at doses well in excess of theoretical therapeutic doses was tolerated with no untoward reactions. Our results demonstrate the potential utility of using a completely synthetic, water soluble globotriaosylceramide analogue, FSL-Gb(3), having low toxicity, for possible future use as a novel therapeutic approach for the systemic treatment of HIV/AIDS.

The human P(k) histo-blood group antigen provides protection against HIV-1 infection.

Several human histo-blood groups are glycosphingolipids, including P/P1/P(k). Glycosphingolipids are implicated in HIV-host-cell-fusion and some bind to HIV-gp120 in vitro. Based on our previous studies on Fabry disease, where P(k) accumulates and reduces infection, and a soluble P(k) analog that inhibits infection, we investigated cell surface-expressed P(k) in HIV infection. HIV-1 infection of peripheral blood-derived mononuclear cells (PBMCs) from otherwise healthy persons, with blood group P(1)(k), where P(k) is overexpressed, or blood group p, that completely lacks P(k), were compared with draw date-matched controls. Fluorescence-activated cell sorter analysis and/or thin layer chromatography were used to verify P(k) levels. P(1)(k) PBMCs were highly resistant to R5 and X4 HIV-1 infection. In contrast, p PBMCs showed 10- to 1000-fold increased susceptibility to HIV-1 infection. Surface and total cell expression of P(k), but not CD4 or chemokine coreceptor expression, correlated with infection. P(k) liposome-fused cells and CD4(+) HeLa cells manipulated to express high or low P(k) levels confirmed a protective effect of P(k). We conclude that P(k) expression strongly influences susceptibility to HIV-1 infection, which implicates P(k) as a new endogenous cell-surface factor that may provide protection against HIV-1 infection.

Induction of HIV-1 resistance: cell susceptibility to infection is an inverse function of globotriaosyl ceramide levels.

To examine the role of the glycosphingolipid (GSL), globotriaosylceramide (Gb(3), CD77, p(k) blood group antigen) in HIV-1 infection, we have pharmacologically modulated Gb(3) metabolism in an X4 HIV-1 infectable monocytic cell line (THP-1) that naturally expresses Gb(3) and in a Gb(3)-expressing glioblastoma cell line (U87) transfected to express both CD4 and CCR5 to permit R5 HIV-1 infection. THP-1 and U87 cells were treated with either a competitive inhibitor of alpha-galactosidase A, 1-deoxygalactonojirimycin (DGJ) to induce Gb(3) accumulation, or a glucosylceramide synthase inhibitor, phenyl-2-palmitylamino-3-pyrrolidino-1-propanol (P4) to deplete cells of Gb(3). HIV susceptibility was determined via measurement of p24(gag) antigen production by ELISA. In addition, total cellular Gb(3) content was determined using thin layer chromatography followed by Verotoxin1 overlay binding. The cell surface expression of Gb(3) was verified by FACS analysis. We found that DGJ significantly decreased THP-1 and U87 cell susceptibility to HIV-1(IIIB) and HIV-1(BaL) infection, respectively, at a concentration of approximately 100 microM. In contrast, P4 (2 microM) substantially increased cellular susceptibility to HIV-1 infection. Total cellular GSL analysis verified increased Gb(3) expression in cells treated with DGJ and considerable reduction of Gb(3) in P4-treated cells as compared to controls. These results show a reciprocal relationship between Gb(3) expression and infection with either X4 HIV-1(IIIB) or R5 HIV-1(Ba-L). These results support previous studies that Gb(3) provides resistance to HIV infection. Variable Gb(3) expression may provide a natural HIV resistance factor in the general population, and pharmacological manipulation of Gb(3) levels may provide an approach to induction of HIV resistance.

Chemical treatment of anti-D results in improved efficacy for the inhibition of Fcgamma receptor-mediated phagocytosis.

BACKGROUND: This study investigated whether treatment of immunoglobulins anti-D or intravenous immune globulin (IVIG) with chemicals previously shown to inhibit phagocytosis could result in an enhancement of Fcgamma receptor (FcgammaR) blockade in vitro. If successful, this approach may provide the possibility of targeting these chemicals to monocyte-macrophages for increased efficacy of immunoglobulin-based therapies in vivo. STUDY DESIGN AND METHODS: For proof-of-concept, the chemical thimerosal, a prototype FcgammaR inhibitor, was combined with RhIG or IVIG. Residual chemical was removed by extensive dialysis. With a monocyte monolayer assay (MMA) and a concentration of immunoglobulin alone that results in 50 percent inhibition of MMA phagocytosis of antibody-coated red blood cells, the effect of thimerosal treatment on the ability of the immunoglobulin to show a significant enhancement of efficacy was determined. RESULTS: It is shown that combining thimerosal with anti-D, either slide and rapid tube or commercially available (WinRho SDF, Cangene), results in a highly significant increase in efficacy over anti-D alone to inhibit phagocytosis in vitro. This effect was not due to residual unbound compound or to cellular toxicity of the chemically treated immunoglobulins. Treatment of IVIG with thimerosal had no significant effect on its ability to inhibit in vitro phagocytosis. CONCLUSION: Our results indicate that it is possible to modify an immunoglobulin by chemical treatment such that the treated immunoglobulin demonstrates significantly enhanced ability to inhibit FcgammaR-mediated phagocytosis. It is also demonstrated that IVIG and anti-D appear to respond differently after chemical treatment. Further examination of this strategy is warranted and has the potential to reduce the dose, cost, and possibly, adverse effects of immunoglobulin-based therapies.