Citations

Remodeling of cell–cell contacts through the internalization of adherens junction proteins is an important event during both normal development and the process of tumor cell metastasis. Here we show that the integrity of tumor cell–cell contacts is disrupted after epidermal growth factor (EGF) stimulation through caveolae-mediated endocytosis of the adherens junction protein E-cadherin. Caveolin-1 and E-cadherin closely associated at cell borders and in internalized structures upon stimulation with EGF. Furthermore, preventing caveolae assembly through reduction of caveolin-1 protein or expression of a caveolin-1 tyrosine phospho-mutant resulted in the accumulation of E-cadherin at cell borders and the formation of tightly adherent cells. Most striking was the fact that exogenous expression of caveolin-1 in tumor cells that contain tight, well-defined, borders resulted in a dramatic dispersal of these cells. Together, these findings provide new insights into how cells might disassemble cell–cell contacts to help mediate the remodeling of adherens junctions, and tumor cell metastasis and invasion.

AbstractStromal elements present within the tumor microenvironment may suppress host immunity and promote the growth of malignant lymphocytes in B cell–derived non-Hodgkin lymphoma (NHL). In contrast, little is known about the microenvironment's role in T cell–derived NHL. B7-H1 (PD-L1, CD274), a member of the B7 family of costimulatory/coinhibitory ligands expressed by both malignant cells and stromal cells within the tumor microenvironment, has emerged as an important immune modulator capable of suppressing host immunity. Therefore, B7-H1 expression and function were analyzed in cutaneous and peripheral T-cell NHL. B7-H1 was expressed by tumor cells, monocytes, and monocyte-derived cells within the tumor microenvironment in T-cell NHL and was found to inhibit T-cell proliferation and promote the induction of FoxP3+ regulatory T cells. Collectively, the data presented provide the first evidence implicating B7-H1 in the suppression of host immunity in T-cell lymphoproliferative disorders and suggest that the targeting of B7-H1 may represent a novel therapeutic approach.

In this study, 65% (132/195) of level B/C obstetric recommendations are amenable to randomized clinical trials (RCTs) and seven were identified as most needed. The purpose of the survey was to evaluate levels B and C recommendations in obstetric practice bulletins (PBs) regarding the feasibility of performing RCT to elevate each subject to level A evidence. Eleven geographically dispersed physicians with experience in research reviewed levels B and C recommendations for the ethical and logistical feasibility of performing an RCT. In the 35 obstetric PBs, 195 level B/C recommendations were reviewed. The majority considered 47 (24%) topics unethical for an RCT and thought 16 (11%) did not need an RCT, thus leaving 132 (67%) levels B and C recommendations available for an RCT. Two-thirds of levels B and C recommendations in obstetric PB are amenable to RCTs and potentially becoming level A evidence.

ABSTRACTPasteurella (Mannheimia) haemolyticaleukotoxin (Lkt) causes cell type- and species-specific effects in ruminant leukocytes. Recent studies indicate thatP. haemolyticaLkt binds to bovine CD18, the common subunit of all β2 integrins. We designed experiments with the following objectives: to identify which member of the β2 integrins is a receptor for Lkt; to determine whether Lkt binding to the receptor is target cell (bovine leukocytes) specific; to define the relationships between Lkt binding to the receptor, calcium elevation, and cytolysis; and to determine whether a correlation exists between Lkt receptor expression and the magnitude of target cell cytolysis. We compared Lkt-induced cytolysis in neutrophils from control calves and from calves with bovine leukocyte adhesion deficiency (BLAD), because neutrophils from BLAD-homozygous calves exhibit reduced β2 integrin expression. The results demonstrate for the first time that Lkt binds to bovine CD11a and CD18 (lymphocyte function-associated antigen 1 [LFA-1]). The binding was abolished by anti-CD11a or anti-CD18 monoclonal antibody (MAb). Lkt-induced calcium elevation in bovine alveolar macrophages (BAMs) was inhibited by anti-CD11a or anti-CD18 MAb (65 to 94% and 37 to 98%, respectively, at 5 and 50 Lkt units per ml;P< 0.05). Lkt-induced cytolysis in neutrophils and BAMs was also inhibited by anti-CD11a or anti-CD18 MAb in a concentration-dependent manner. Lkt bound to porcine LFA-1 but did not induce calcium elevation or cytolysis. In neutrophils from BLAD calves, Lkt-induced cytolysis was decreased by 44% compared to that of neutrophils from control calves (P< 0.05). These results indicate that LFA-1 is a Lkt receptor, Lkt binding to LFA-1 is not target cell specific, Lkt binding to bovine LFA-1 correlates with calcium elevation and cytolysis, and bovine LFA-1 expression correlates with the magnitude of Lkt-induced target cell cytolysis.

Rituximab improves outcomes for persons with lymphoproliferative disorders and is increasingly used to treat immune-mediated illnesses. Recent reports describe 2 patients with systemic lupus erythematosus and 1 with rheumatoid arthritis who developed progressive multifocal leukoencephalopathy (PML) after rituximab treatment. We reviewed PML case descriptions among patients treated with rituximab from the Food and Drug Administration, the manufacturer, physicians, and a literature review from 1997 to 2008. Overall, 52 patients with lymphoproliferative disorders, 2 patients with systemic lupus erythematosus, 1 patient with rheumatoid arthritis, 1 patient with an idiopathic autoimmune pancytopenia, and 1 patient with immune thrombocytopenia developed PML after treatment with rituximab and other agents. Other treatments included hematopoietic stem cell transplantation (7 patients), purine analogs (26 patients), or alkylating agents (39 patients). One patient with an autoimmune hemolytic anemia developed PML after treatment with corticosteroids and rituximab, and 1 patient with an autoimmune pancytopenia developed PML after treatment with corticosteroids, azathioprine, and rituximab. Median time from last rituximab dose to PML diagnosis was 5.5 months. Median time to death after PML diagnosis was 2.0 months. The case-fatality rate was 90%. Awareness is needed of the potential for PML among rituximab-treated persons.

Abstract Several DXA-based structural engineering models (SEMs) of the proximal femur have been developed to estimate stress caused by sideway falls. Their usefulness in discriminating hip fracture has not yet been established and we therefore evaluated these models. The hip DXA scans of 51 postmenopausal women with hip fracture (30 femoral neck, 17 trochanteric, and 4 unspecified) and 153 age-, height-, and weight-matched controls were reanalyzed using a special version of Hologic's software that produced a pixel-by-pixel BMD map. For each map, a curved-beam, a curved composite-beam, and a finite element model were generated to calculate stress within the bone when falling sideways. An index of fracture risk (IFR) was defined over the femoral neck, trochanter, and total hip as the stress divided by the yield stress at each pixel and averaged over the regions of interest. Hip structure analysis (HSA) was also performed using Hologic APEX analysis software. Hip BMD and almost all parameters derived from HSA and SEM were discriminators of hip fracture on their own because their ORs were significantly &gt;1. Because of the high correlation of total hip BMD to HSA and SEM-derived parameters, only the bone width discriminated hip fracture independently from total hip BMD. Judged by the area under the receiver operating characteristics curve, the trochanteric IFR derived from the finite element model was significant better than total hip BMD alone and similar to the total hip BMD plus bone width in discriminating all hip fracture and femoral neck fracture. No index was better than total hip BMD for discriminating trochanteric fractures. In conclusion, the finite element model has the potential to replace hip BMD in discriminating hip fractures.

Abstract Purpose: Although the prognostic value of B7-H1 and B7-H4 expression by tumor cells in clear cell renal cell carcinoma (ccRCC) has been established, the role of B7-H3 is unknown. As such, we evaluated the association of B7-H3 expression with clinicopathologic outcomes in patients treated for ccRCC. Experimental Design: Nephrectomy specimens from 743 consecutive patients treated for ccRCC at our institution from 1990 to 1999 were evaluated for B7-H3 expression by immunohistochemical staining. Associations of B7-H3 expression with clinical and pathologic features were evaluated using χ2 and Fisher's exact tests. Associations of B7-H3 expression with death from RCC were evaluated using Cox proportional hazards regression models. Results: B7-H3 expression by tumor cells or tumor vasculature was noted in 17% and 95% of specimens, respectively. The presence of either tumor cell or diffuse tumor vasculature expression of B7-H3 was present in 46% of specimens and was associated with multiple adverse clinical and pathologic features. After multivariable adjustment, the presence of either tumor cell or diffuse tumor vasculature B7-H3 expression was significantly associated with an increased risk of death from RCC (risk ratio, 1.38; 95% confidence interval, 1.03-1.84; P = 0.029). Conclusions: Both tumor cell and tumor vasculature B7-H3 expression convey important information to predict ccRCC outcomes. Collectively, our past and present studies pertaining to B7-H ligand expression indicate that ccRCC may use redundant mechanisms to compromise host antitumoral immunity. Future studies will focus on the effect of combined B7-H ligand expression in RCC.

Abstract B7x is the newest member of the B7-CD28 family and is thought to dampen immune responses via negative costimulation. Tumor expression of B7x was recently described in renal cell carcinoma (RCC) and was associated with poor outcome. We developed an assay to detect serum-soluble B7x (sB7x) and investigated 101 patients with clear cell RCC who underwent nephrectomy between 2003 and 2007. For controls, we obtained serum from 101 sex-matched blood donors within the same age range. Following an ELISA for sB7x, detectable levels (&gt;0.1 ng/mL) of sB7x were observed in 53 RCC patients compared with 18 controls (P &lt; 0.001). Median (range) concentrations of sB7x for RCC patients and controls were 14.4 ng/mL (0.1–56.9) and 2.7 ng/mL (0.2–37.1), respectively. For RCC patients with detectable sB7x, median levels were significantly higher for patients with a tumor thrombus (19.2 versus 6.6 ng/mL; P = 0.007), positive lymph nodes (41.3 versus 10.3 ng/mL; P = 0.018), and distant metastases at nephrectomy (43.3 versus 8.5 ng/mL; P = 0.002) and tended to be higher in patients with high-grade tumors (18.8 versus 8.5; P = 0.090). Additionally, median sB7x levels for tumor-node-metastasis stage I to IV RCC were 6.6, 10.3, 14.5, and 43.3 ng/mL, respectively (P = 0.012). In this first evaluation of sB7x in RCC, we show that RCC patients are more likely to have detectable sB7x compared with controls and higher sB7x levels correlate with advanced tumor stage. These early results merit further investigation of this serum marker for potential diagnostic and prognostic purposes. [Cancer Res 2008;68(15):6054–8]

Abstract Purpose: Aberrant expression of T-cell coregulatory molecules has been investigated as a mechanism by which certain cancers may evade host immune surveillance. We evaluated expression of the T-cell coregulators B7-H1, B7-H3, and PD-1 in urothelial cell carcinoma (UCC) of the bladder. Experimental Design: Immunohistochemistry for B7-H1, B7-H3, and PD-1 was done on paraffin-embedded sections from 318 consecutive patients with UCC who underwent radical cystectomy. Expression was correlated with clinicopathologic outcomes and postoperative survival. Results: B7-H3 was widely expressed in UCC, as 222 of 314 (70.7%) tumors showed positive staining. Expression of B7-H3 in UCC was significantly increased compared with adjacent, nontumor urothelium, as a median of 70% of tumor cells expressed B7-H3, compared with 20% of cells in nontumor specimens (P &lt; 0.001). The increase in B7-H3 expression was independent of tumor stage (P = 0.13). Expression of B7-H1 by UCC tumors (P &lt; 0.001) and PD-1 by tumor-infiltrating lymphocytes (P = 0.012) were significantly associated with increased pathologic stage. Patients who had received intravesical bacillus Calmette-Guerin before cystectomy tended to show increased expression of B7-H3 (P = 0.023) and PD-1 (P = 0.071) but were less likely to express B7-H1 (P = 0.027). Moreover, for the subset of patients with organ-confined disease (n = 167), B7-H1 expression independently predicted all-cause mortality after cystectomy (hazard ratio, 3.18; 95% confidence interval, 1.74-5.79; P &lt; 0.001). Conclusions: B7-H3 is highly expressed in UCC across tumor stages, whereas B7-H1 and PD-1 expression are associated with advanced disease. B7-H1 expression predicts mortality after cystectomy for patients with organ-confined tumors. These molecules may represent novel diagnostic or prognostic markers, as well as therapeutic targets, for patients with UCC.