Citations

Abstract Kaposi's sarcoma (KS) is the most common neoplasm in untreated AIDS patients and accounts for significant morbidity and mortality worldwide. We have recently reported that Notch signaling (which plays an important role in cell proliferation, apoptosis, and oncogenesis) is constitutively activated in KS tumor cells. Blockade of this activity using γ-secretase inhibitors resulted in apoptosis of SLK cells, a KS tumor cell line; however, this apoptosis was preceded by a prolonged G2-M cell cycle arrest. This result led us to hypothesize that the cells were undergoing mitotic catastrophe, an abnormal mitosis that leads to eventual cell death. Here, we show that Notch inhibition in KS tumor cells using γ-secretase inhibitors or Notch-1 small interfering RNA resulted in G2-M cell cycle arrest and mitotic catastrophe characterized by the presence of micronucleated cells and an increased mitotic index. Interestingly, Notch inhibition led to a sustained increase in nuclear cyclin B1, a novel observation suggesting that Notch signaling can modulate expression of this critical cell cycle protein. Further analysis showed the induction of cyclin B1 was due, at least in part, to increased nuclear factor-κB (NF-κB) activity, which was also required for the G2-M growth arrest after Notch inhibition. Taken together, these studies suggest that Notch inhibition can initiate aberrant mitosis by inducing NF-κB activity that inappropriately increases cyclin B1 resulting in cell death via mitotic catastrophe. [Mol Cancer Ther 2007;6(7):1983–92]

Studies of the immunohistochemical profiles and clinical course of desmoplastic melanoma have produced conflicting results. We identified 28 cases of desmoplastic melanoma after a search of our files for spindle cell neoplasms of the head and neck from 1960 through 1995. The 17 male (61%) and 11 female (39%) patients averaged 65 years of age. The cheek was the most common location (12 cases, 43%). The average length of follow-up was 5 years. Overall 5-year survival rate was 46%. Melan A and tyrosinase positivity (P = 0.0195), smooth muscle actin positivity (P = 0.0328), tumor size (P = 0.0297), and tumor thickness (P = 0.0419) were significantly associated with local progression-free survival. No histologic or immunohistochemical marker was associated with overall or metastasis-free survival.

OBJECTIVETo evaluate hearing outcomes and effects of stimulation rate on performance with the Nucleus Freedom cochlear implant (Cochlear Americas, Denver, CO).STUDY DESIGN AND SETTINGRandomized, controlled, prospective, single‐blind clinical study using single‐subject repeated measures (A‐B‐A‐B) design at 14 academic centers in the United States and Canada and comparison with outcomes of a prior device by the same manufacturer.PATIENTSSeventy‐one severely/profoundly hearing impaired adults.RESULTSSeventy‐one adult recipients were randomly programmed in two different sets of rate: ACE or higher rate ACE RE. Mean scores for Consonant Nucleus Consonant words is 57%, Hearing in Noise Test (HINT) sentences in quiet 78%, and HINT sentences in noise 64%. Sixty‐seven percent of subjects preferred slower rates of stimulation, and performance did not improve with higher rates of stimulation using this device.CONCLUSIONSSubjects performed well, and there was no advantage to higher stimulation rates with this device.SIGNIFICANCEHigher stimulation rates do not necessarily result in improved performance.

Abstract Background: The International Staging System for multiple myeloma has increased the importance of accurate measurement of serum albumin. Two common albumin assays, bromcresol green (BCG) and agarose gel protein electrophoresis (PEL), frequently yield discordant results, creating confusion regarding which assay is superior for use in myeloma. Methods: We measured albumin by BCG on a Roche Modular system, by PEL with a Helena SPIFE SPE Vis agarose gel, and by immunonephelometry performed on a Dade Behring BNII nephelometer. BCG and PEL were used to measure albumin in 5777 patient samples, and all 3 methods were used in an additional 252 samples. The clinical impact was assessed on 698 myeloma patient samples. Results: For sera with zero/low monoclonal immunoglobulin protein (M)-spike (0 to <15 g/L), results for both BCG and PEL correlated well to nephelometry, although median PEL results were 8 g/L lower than corresponding BCG measurements. Correlation between PEL and nephelometry or BCG diminished with increasing M-spike, with PEL eventually overestimating albumin compared with both other assays. IgG and IgA M-spikes showed significantly different effects on albumin discordance. For 35% of myeloma patients, discrepancy between BCG and PEL had a potentially clinically significant effect on staging, but no difference in group survival was found. Conclusions: Both BCG and PEL correlate well to nephelometry in sera with zero/low M-spikes. In the presence of larger M-spikes, PEL correlates poorly to nephelometry or BCG, whereas BCG compares well with nephelometry regardless of M-spike. Thus, albumin measurement can be performed reliably in myeloma patient sera by use of inexpensive, automated BCG assays.

AbstractPurpose: Regulatory T cells (Tregs) have been implicated as inhibitors of antitumoral immunity, and evidence suggests that elimination of Tregs may augment natural and pharmacologic immunity. We tested for the presence of putative Tregs within renal cell carcinoma (RCC) tumors.Experimental Design: We identified 170 patients who underwent radical or partial nephrectomy for clear cell RCC between 2000 and 2002. Specimens were stained with anti-CD4, anti-CD25, and anti-Foxp3 antibodies and examined using confocal microscopy. Associations of CD4+CD25+Foxp3− and CD4+CD25+Foxp3+ T cells with death from RCC were evaluated using Cox proportional hazards regression models.Results: At last follow-up, 46 of 170 patients had died; of these, 37 died from RCC at a median of 1.4 years following nephrectomy (range, 0-4.4). Among the 124 remaining patients, median follow-up was 3.7 years (range, 0-5.7). Forty-three (25.3%) tumors harbored CD4+CD25+Foxp3+ T cells. The presence of Foxp3+ T cells was not significantly associated with RCC death univariately. One hundred forty-three (84.1%) tumors harbored CD4+CD25+Foxp3− T cells. The indicator for ≥10% CD4+CD25+Foxp3− T cells was significantly associated with RCC death univariately [risk ratio (RR), 2.60; 95% confidence interval (95% CI), 1.35-4.98; P = 0.004], after adjusting for tumor B7-H1 expression (RR, 2.53; 95% CI, 1.32-4.85; P = 0.005) and lymphocytic infiltration (RR, 2.53; 95% CI, 1.32-4.87; P = 0.005).Conclusions: Increased presence of CD4+CD25+Foxp3+ T cells was not significantly associated with RCC death. In contrast, CD4+CD25+Foxp3− T cells, which may represent a unique set of Tregs or activated helper T cells, was significantly associated with outcome.

Caveolar endocytosis is an important mechanism for the uptake of certain pathogens and toxins and also plays a role in the internalization of some plasma membrane (PM) lipids and proteins. However, the regulation of caveolar endocytosis is not well understood. We previously demonstrated that caveolar endocytosis and β1-integrin signaling are stimulated by exogenous glycosphingolipids (GSLs). In this study, we show that a synthetic GSL with nonnatural stereochemistry, β-d-lactosyl-N-octanoyl-l-threo-sphingosine, (1) selectively inhibits caveolar endocytosis and SV40 virus infection, (2) blocks the clustering of lipids and proteins into GSLs and cholesterol-enriched microdomains (rafts) at the PM, and (3) inhibits β1-integrin activation and downstream signaling. Finally, we show that small interfering RNA knockdown of β1 integrin in human skin fibroblasts blocks caveolar endocytosis and the stimulation of signaling by a GSL with natural stereochemistry. These experiments identify a new compound that can interfere with biological processes by inhibiting microdomain formation and also identify β1 integrin as a potential mediator of signaling by GSLs.

AbstractPurpose: Clear cell renal cell carcinoma (ccRCC) is an immunogenic tumor that can progress in the presence of an intact host immune system. We previously reported that survivin and B7-H1 are independently associated with disease progression and death when expressed by ccRCC tumors. Herein, we examine the clinical effect of ccRCC combined expression of both survivin and B7-H1.Experimental Design: Specimens from 298 patients who underwent nephrectomy for ccRCC between 1990 and 1994 were immunohistochemically stained for survivin and B7-H1. Cancer-specific survival was estimated using the Kaplan-Meier method. Associations of both markers with ccRCC death were assessed using Cox proportional hazards regression models.Results: At last follow-up, 94 patients died from ccRCC. Among the living patients, the median follow-up was 11.2 years (range, 0-15 years). There were 177 (59.4%) survivinLow/B7-H1−, 51 (17.1%) survivinHi/B7-H1−, 29 (9.7%) survivinLow/B7-H1+, and 41 (13.8%) survivinHi/B7-H1+ tumors. The 5-year cancer-specific survival rates for patients within each group were 89.3%, 59.7%, 70.0%, and 16.2%, respectively. Combined survivinHi/B7-H1+ expression was associated with ccRCC death univariately (risk ratio, 12.82; 95% confidence interval, 7.50-21.92; P < 0.001) and in multivariate analysis (risk ratio, 2.81; 95% confidence interval, 1.56-5.04; P < 0.001). SurvivinHi/B7-H1+ tumors exhibited increased levels of infiltrating mononuclear cells and survivin-specific T cells compared with survivinLow/B7-H1− tumors.Conclusion: Patients with survivinHi/B7-H1+ ccRCC tumors are at increased risk of ccRCC death. SurvivinHi/B7-H1+ tumors also harbor increased amounts of infiltrating mononuclear cells and survivin-specific T cells relative to survivinLow/B7-H1− tumors. Taken together, dual expression of survivin and B7-H1 can be used to predict ccRCC tumor aggressiveness.