Artificial dry surface biofilm models for testing the efficacy of cleaning and disinfection

Dry surface biofilms (DSB) harbouring pathogens are widespread in healthcare settings, are difficult to detect and are resistant to cleaning and disinfection interventions. Here, we describe a practical test protocol to palliate the lack of standard efficacy test methods for DSB. Staphylococcus aureus DSB were produced over a 12-day period, grown with or without the presence of organic matter, and their composition and viability were evaluated. Disinfectant treatment was conducted with a modified ASTM2967-15 test and reduction in viability, transferability and biofilm regrowth post-treatment were measured. Dry surface biofilms produced over a 12-day period had a similar carbohydrates, proteins and DNA content, regardless of the presence or absence of organic matter. The combination of sodium hypochlorite (1000 ppm) and a microfiber cloth was only effective against DSB in the absence of organic load. With the increasing concerns of the uncontrolled presence of DSB in healthcare settings, the development of effective intervention model in the presence of organic load is appropriate for the testing of biocidal products, while the use of three parameters, log₁₀ reduction, transferability and regrowth, provides an accurate and practical measurement of product efficacy. SIGNIFICANCE AND IMPACT OF THE STUDY: The widespread presence of biofilms on dry surfaces in healthcare settings has been recently documented. These dry surface biofilms (DSB) present an unprecedented challenge to cleaning and disinfection processes. Here, we describe a practical efficacy protocol based on an in vitro Staphylococcus aureus DSB model. The protocol measures reduction in viability, transferability and biofilm regrowth post-treatment to provide altogether a practical assessment of product efficacy against dry surface biofilms.

T-antigen of sv40 blocks p53 transactivation but not p53 specific binding to DNA

The p53 is a DNA binding phosphoprotein that can act as a transcriptional activator through high affinity DNA binding sequences (HBS). The large T antigen (LT-ag) of SV40 virus can bind p53 and their association is considered important for transforming activities of the virus. In this study, we investigated the effects of LT-ag on transcriptional transactivating function of p53 using cotransfection assays and DNA-binding electrophoretic mobility shift assays. A reporter gene containing a minimal TK promoter and two copies of HBS for p53 was cotransfected with p53 and LT-ag expression vector into human SKOV3 cells (p53 non-expressor). The LT-ag inhibited in a dose-dependent fashion transactivation by wild-type p53. The LT-ag was unable to inhibit transactivation of a reporter gene containing a similar promoter (TK). The LT-ag mutants defective for binding to p53, failed to inhibit transactivation. The LT-ag inhibited the transactivation of a CAT reporter gene containing the GAL4-DNA recognition sequences by the p53 protein which was fused to the heterologous DNA binding domain (amino acids 1-147 of GAL4) in cotransfected cells showing that inhibition of p53 activities by LT-ag was not restricted to the p53 HBS-dependent reporter. LT-ag failed to inhibit GAL4-p53 fragment containing the transactivating, but non-LT-ag binding region of p53, showing the importance of LT-ag binding to p53 in order to restrict p53 transactivation. Immunohistochemical analysis showed that in SKOV3, nuclear localization of wild type p53 was unaffected by coexpressed LT-ag. Gel shift analysis determined that nuclear extract from cells cotransfected with p53 and LT-ag expression vectors contained p53 not associated with LT-ag; this free p53 was able to bind to the HBS. These results suggest that LT-ag of SV40 preferentially binds the transcriptionally active p53, preventing it from transactivating through p53-HBS; the transcriptionally inactive p53 in these cells can still bind p53-HBS.

OS046. Genome-wide association scans identify novel maternalsusceptibility loci for preeclampsia

INTRODUCTION

We have successfully utilized a family-based study design to localize several positional candidate preeclampsia susceptibility genes to chromosomes 2q22(ACVR2A,LCT,LRP1B,RND3,GCA),5q (ERAP2) and 13q(TNFSF13B). We now report on our continued positional cloning efforts using an alternative genome-wide association (GWA) mapping strategy in large Caucasian case-control cohorts from Australia and Norway.

OBJECTIVES

To identify maternal genetic risk loci for preeclampsia.

METHODS

The unrelated Australian samples (545 cases,547 controls) were genotyped using Illumina BeadChip technology (700K loci) and have been analyzed using PLINK. All unrelated Norwegian samples were genotyped across several Illumina BeadChip substrates and consist of 847 cases (700K loci) and 638 controls. The Norwegian control samples originate from other HUNT studies pertaining to migraine (n=95,700K loci), lung cancer (n=89,370K loci) and normal brain pathology (n=454,2.5M loci). To analyze a concordant set of 2.5-3 million genotypes across all Norwegian samples we are currently using MaCH to impute those loci not directly genotyped. The Norwegian GWA data will be analyzed in SOLAR utilizing empirical kinship estimates to account for any distant relatedness.

RESULTS

1078 Australian samples (538 cases,540 controls) and 648, 175 SNPs passed our quality control metrics. Two SNP associations (rs7579169,p=3.6×10(-7); rs12711941,p=4.3×10(-7)) satisfied our genome-wide significant threshold (p<5.1×10(-7)). These SNPs reside less than 15kb downstream from the 3 terminus of the Inhibin, beta B (INHBB) gene on 2q14.2. Sequencing of the INHBB locus in our patient cohort identified a third intergenic SNP to significantly associate with preeclampsia (rs7576192,p=1.5×10(-7)). These three SNPs confer risk (OR>1.56) and are in strong linkage disequilibrium with each other (r(2)>0.9) but not with any other genotyped SNP ±200kb. The analysis of the Norwegian GWAS is underway.

CONCLUSION

The Australian GWAS has identified a novel preeclampsia risk locus on chromosome 2q. The INHBB gene closest to our SNP associations is a plausible positional candidate susceptibility gene. There is a substantive body of evidence implicating inhibins, activins and other members of the TGF-βsuperfamily to have a role in the development of preeclampsia. The biological connection between ACVR2A and INHBB leads us to speculate that our linkage-based and GWA-based study designs, respectively, have identified a key biological pathway involved in susceptibility to preeclampsia.

Effect of dasatinib against thyroid cancer cell lines in vitro and a xenograft model in vivo

Tyrosine kinase inhibitors (TKIs) have emerged as a promising class of agents against thyroid cancer. The aim of the present study was to investigate the in vitro and in vivo activity of dasatinib against a panel of thyroid cancer cell lines and explore possible mechanisms of action, using various assays and western blotting. Our results showed that dasatinib exhibits prominent cytostatic activity both in vitro and in vivo against thyroid cancer cell lines with RET/PTC rearrangement (BHP2-7) and KRAS mutation (Cal62). Although dasatinib has primarily been described as an ABL/SRCfamily kinase inhibitor, the cytostatic activity observed in the present study is mediated by several off-target effects of dasatinib, some of which have not previously been reported. These effects include a reduction in phospho-FAK, FAK, RAS, Caveolin and SYK protein levels and an increase in β-catenin protein expression, which leads to the induction of senescence, an increase in the adhesiveness of the cells, a decrease in reactive oxygen species level, and changes in the expression profile of molecules involved in cellular adhesion such as integrins. Therefore, we propose that dasatinib is an effective therapeutic agent for certain patients with thyroid cancer, and these candidate patients may be identifiable on the basis of standard genotypic analyses.

Impact of pathologic tumor characteristics in patients with sarcomatoid renal cell carcinoma

343

Background: Patients with sarcomatoid renal cell carcinoma (sRCC) are known to have a poor prognosis and response to therapy. We sought to determine the influence of pathologic tumor characteristics on outcome in order to aid clinical management.

Methods: A single center database was reviewed from 1989-2009 to identify all patients with sRCC. Clinical and staging variables were collected and pathologic information including histology, necrosis, percentage of sarcomatoid features (PSF), and microvascular invasion (MVI) was recorded. Influence of clinicopathologic variables on outcome was assessed.

Results: A total of 104 patients had confirmed sRCC. The median size of tumors was 9.5 cm (range 2.5-30), 65% of patients had areas of clear cell RCC, and 69.2% had metastatic disease at presentation. The PSF did not influence tumor size, stage, necrosis, MVI, nodes, or metastasis. A total of 85 patients (81.7%) died during the follow-up period with a median survival of 5.9 months. In the overall cohort poor performance status, metastatic disease, and MVI were independent predictors of poor survival. Increased PSF was associated with worse outcome, but it failed to reach significance on multivariate analysis. In a subset analysis of those with non-metastatic disease, MVI and non-clear histology influenced prognosis, but only PSF was the only predictor of outcome.

Conclusions: The PSF has limited influence on pathologic characteristics. However, increased PSF amounts may impact survival, especially in those with non-metastatic disease. The presence of MVI is an independent predictor of poor outcome while carcinoma grade and subtype have limited impact on survival. When counseling patients or designing clinical trials for these patients, PSF and MVI, not carcinoma grade or subtype should be considered.

No significant financial relationships to disclose.

In vivo activity of rituximab-CpG oligodeoxynucleotide conjugate against rituximab-resistant human CD20+ B-cell lymphoma

8529

Background: The anti-CD20 monoclonal antibody rituximab (R) is a mainstay in the treatment of B cell non-Hodgkin's lymphoma (NHL), exerting anti-tumor effects via antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity, and apoptosis induction. Toll-like receptor 9 agonist CpG oligodeoxynucleotides (CpG) are potent activators of ADCC and T cell immunity, and have been studied for anti-NHL effects when administered by systemic or intratumoral routes. We sought to optimize the delivery of CpG to sites of NHL to improve R efficacy. Methods: We utilized an aggressive syngeneic human CD20-expressing murine B cell lymphoma (38C13-huCD20) to study the in vivo augmentation of R efficacy by CpG. Established tumors in immunocompetent mice were treated with R plus CpG given systemically, intratumorally, or chemically linked to antibody using maleimide-sulfhydryl chemistry (D. Betting et al, J. Immunol. 2008; 181: 4131). Results: 5- to 7-day established tumors were completely resistant to single agent R. Combining intratumoral, but not systemic administration of CpG with R resulted in tumor eradication from up to 42% of mice (p < 0.0003 vs. R alone, CpG alone, R + systemic CpG). Mechanistic studies indicated that both natural killer cells and complement participated in the cure of tumors by intratumoral CpG + R, by increasing tumor cell sensitivity to complement and ADCC lysis, and by augmenting the cytotoxicity of ADCC effectors. To overcome the need for repeated direct intratumoral injections and allow precise targeting of CpG to tumor cells, we chemically linked CpG to R using a cleavable linker. A single i.v. injection of this R-CpG conjugate achieved eradication of established tumors from 100% of mice. In contrast, equivalent doses of unlinked i.v. R + CpG, CpG alone, or R alone cured only 8% of mice. Thus, combining CpG with R was most effective using direct conjugation to the antibody. Conclusions: In conclusion, enhancement of R efficacy required sustained intratumoral delivery of CpG to maximize anti-tumor responses. R-CpG conjugate efficiently eradicated an established B cell lymphoma that is fully resistant to single-agent R. Clinical testing of anti-CD20-CpG conjugates against B cell NHL is thus warranted.

[Table: see text]

Use of chromosome 9p status to identify a subset of high-risk localized renal cell carcinoma

5090

Background: We investigated whether deletion of chromosome 9p in clear cell renal cell carcinoma (ccRCC) predicts worse disease-specific (DSS) and recurrence-free survival (RFS), and if it is associated with worse prognosis in tumors < 4 cm. Methods: 316 patients undergoing nephrectomy prior to 2001 were included on a tissue microarray in whom FISH analysis using the LSI p16/CEP 9 Dual Color Probe was performed to assess chromosome 9p deletion status. An additional 389 patients undergoing nephrectomy after 2001 had 9p status determined by standard cytogenetics. Tumor grade, stage, size, 9p status, nodal involvement, and the presence of metastasis were recorded. Disease-specific and recurrence-free survival were determined, and independence was assessed using Cox proportional hazards models. Results: 9p deletions were detected in 14% of tumors. 54% of 9p-deleted tumors were high grade (G3–4) vs. 38% without 9p deletions, and 60% of 9p-deleted tumors were T3–4 vs 38% without 9p deletions (p < 0.01). 55% of those with 9p deletions had positive nodes or metastases vs. 34% of those without 9p deletions (p < 0.01). Median DSS for those with and without 9p deletions was 80 months and 37 months, respectively (p < 0.01). In localized disease, median RFS for those with 9p deletions was 53 months and was not reached in those without 9p deletions (p<0.01). In 188 patients presenting with localized RCC < 4 cm, loss of 9p occurred in 3/7 (42.9%) of patients with post-nephrectomy recurrence vs. 13/168 (7.2%) of patients without disease recurrence (p = 0.001). DSS for patients with 9p deletion in tumors < 4 cm was significantly worse than DSS in those without 9p deletions (HR 6.18; p = 0.02), and an independent effect on RFS was seen for 9p deletions in localized RCC (HR 2.3, p < 0.01). 9p status was not a significant predictor in metastatic RCC. Conclusions: Deletion of chromosome 9p in ccRCC occurs in 14% of patients and is associated with higher grade and T stage, presence of nodal and distant disease, worse prognosis, and in patients with small NOMO tumors, 9p deletions but not tumor size was independently associated with RFS. Identifying high risk patients with 9p deletions will allow better risk stratification for surveillance protocols and for adjuvant trials.

No significant financial relationships to disclose.

Expression of programmed death ligand 1 (PD-L1) by non-Hodgkin's lymphomas (NHL) and effect on tumor-associated T cells

8526

Background: PD-L1 is expressed on antigen presenting cells and inhibits activation of T cells through its receptor, PD-1. PD-L1 is aberrantly expressed on epithelial malignancies and may prevent an effective host anti-tumor immune response. The role of PD-L1 in NHL is unknown. Methods: PD-L1 expression was analyzed in 16 NHL cell lines by flow cytometry (FC) and in 111 lymphoma specimens by immunohistochemistry (IHC) (n=92) or FC (n=19). In functional studies, irradiated anaplastic large cell lymphoma (ALCL) cells were co-cultured with allogeneic T cells in the presence of anti-PD-L1 blocking antibody, and IFNγ secretion and thymidine incorporation was used to assess T cell function and proliferation. To further test tumor-T cell interactions, malignant ascites from a patient with ALK+ ALCL and peripheral blood mononuclear cells from a patient with leukemic mantle cell lymphoma, both containing PD-L1-expressing tumor cells and tumor-associated T cells, were stimulated with phytohemagglutinin (a polyclonal T cell activator) and incubated with anti-PD-L1 antibody. Levels of 16 inflammatory cytokines were measured as an assessment of T cell activity. Results: All 9 B cell lymphoma lines were negative for PD-L1, while all 5 ALCL cell lines were strongly positive. One T-cell ALL line was positive, and one peripheral T cell lymphoma was negative. Strong PD-L1 staining was detected by IHC in all 14 ALCL specimens and in 83% of diffuse large B cell lymphomas (DLBCL) analyzed (n=35). Activity of allogeneic T cells co-cultured with irradiated ALCL cells, as measured by IFNγ secretion and proliferation, was markedly enhanced in the presence of anti-PD-L1 blocking antibody. In the autologous setting using cultures of ALCL and mantle cell lymphoma specimens containing host T cells, secretion of inflammatory cytokines by tumor-associated T cells, including GMCSF, IFNγ, IL-1, IL-6, IL-8, TNFα, and MIP1α, were increased by incubation with anti-PD-L1 antibody. Conclusions: PD-L1 is highly expressed in ALCL and in a majority of DLBCL. Blockade of tumor-associated PD-L1 promoted activation of adjacent T cells. PD-L1 may play a role in thwarting an effective anti-tumor immune response and represents an attractive target for lymphoma immunotherapy.

No significant financial relationships to disclose.

Induction of sodium iodide symporter gene and molecular characterisation of HNF3 beta/FoxA2, TTF-1 and C/EBP beta in thyroid carcinoma cells

Thyroid carcinoma cells often do not express thyroid-specific genes including sodium iodide symporter (NIS), thyroperoxidase (TPO), thyroglobulin (TG), and thyrotropin-stimulating hormone receptor (TSHR). Treatment of thyroid carcinoma cells (four papillary and two anaplastic cell lines) with histone deacetylase inhibitors (SAHA or VPA) modestly induced the expression of the NIS gene. The promoter regions of the thyroid-specific genes contained binding sites for hepatocyte nuclear factor 3 β (HNF3β)/forkhead box A2 (FoxA2), thyroid transcription factor 1 (TTF-1), and CCAAT/enhancer binding protein β (C/EBPβ). Quantitative reverse transcription-polymerase chain reaction (RT–PCR) showed decreased expression of HNF3β/FoxA2 and TTF-1 mRNA in papillary thyroid carcinoma cell lines, when compared with normal thyroid cells. Forced expression of these genes in papillary thyroid carcinoma cells inhibited their growth. Furthermore, the CpG island in the promoter region of HNF3β/FoxA2 was aberrantly methylated; and treatment with 5-aza-2-deoxycytidine (5-Az) induced its expression. Immunohistochemical staining showed that C/EBPβ was localised in the nucleus in normal thyroid cells but was detected in the cytoplasm in papillary thyroid carcinoma cells. Subcellular fractionation of papillary thyroid carcinoma cell lines also demonstrated high levels of expression of C/EBPβ in the cytoplasm, suggesting that a large proportion of C/EBPβ protein is inappropriately localised in the cytoplasm. In summary, these findings reveal novel abnormalities in thyroid carcinoma cells

Use of carbonic anhydrase IX (CAIX) expression and Von Hippel Lindau (VHL) gene mutation status to predict survival in renal cell carcinoma

5042

Background: VHL gene mutations induce the expression of CAIX, and previous studies have shown that low CAIX results in worse prognosis for RCC. We attempt to further describe the relationship between CAIX expression, VHL gene mutations and tumor characteristics. Methods: Radical nephrectomy was performed in 100 patients at 2 centers. Genomic DNA was extracted from frozen tumor samples using the QIAmp DNA mini kit. Four amplimers covering the whole coding sequence of the VHL gene were synthesized by PCR and sequenced by Big Dye. Mutation bearing sequences were confirmed by a second round of sequencing. The monoclonal antibody M75 was used to score the expression of the CAIX protein. Life table, Kaplan-Meier and Cox regression analyses addressed RCC-specific mortality (RCC-SM). Results: VHL mutations were identified in 58 patients (58%) and CAIX tumor expression ranged from 0% to 100%. Low CAIX expression (<85%) was associated with absence of VHL mutation (p=0.02), larger tumors (p=0.002), higher T stage (p=0.007), nodal metastases (p=0.001) and higher Fuhrman grade (p=0.006). Absence of VHL mutation was associated with worse ECOG (p=0.005), higher T stage (p=0.01) and presence of nodal (p=0.03) and distant metastases (p=0.02). Categorically-coded, CAIX was a statistically significant predictor of RCC-SM (p=0.002), while VHL mutation approached statistical significance (p=0.08) and a trend was observed for worse survival when VHL was not mutated. Patients with both high CAIX and VHL mutation had better survival (95.9% 1 year and 6 year median survival) than their counterparts with low CAIX expression and absence of VHL mutation (62.9% 1 year and 1.5 year median survival) (p<0.001). In Cox regression analyses, neither CAIX (p=0.06) nor VHL (p=0.4) achieved independent predictor status, when adjusted for age, gender, TNM stage, tumor size, Fuhrman and ECOG. Conclusions: Low CAIX expression is associated with the absence of VHL mutation and aggressive tumor characteristics, and is a statistically significant predictor of poor prognosis in patients with clear cell RCC.

No significant financial relationships to disclose.

Global DNA methylation profiling reveals silencing of a secreted form of Epha7 in mouse and human germinal center B-cell lymphomas

Most human lymphomas originate from transformed germinal center (GC) B lymphocytes. While activating mutations and translocations of MYC, BCL2 and BCL6 promote specific GC lymphoma subtypes, other genetic and epigenetic modifications that contribute to malignant progression in the GC remain poorly defined. Recently, aberrant expression of the TCL1 proto-oncogene was identified in major GC lymphoma subtypes. TCL1 transgenic mice offer unique models of both aggressive GC and marginal zone B-cell lymphomas, further supporting a role for TCL1 in B-cell transformation. Here, restriction landmark genomic scanning was employed to discover tumor-associated epigenetic alterations in malignant GC and marginal zone B-cells in TCL1 transgenic mice. Multiple genes were identified that underwent DNA hypermethylation and decreased expression in TCL1 transgenic tumors. Further, we identified a secreted isoform of EPHA7, a member of the Eph family of receptor tyrosine kinases that are able to influence tumor invasiveness, metastasis and neovascularization. EPHA7 was hypermethylated and repressed in both mouse and human GC B-cell non-Hodgkin lymphomas, with the potential to influence tumor progression and spread. These data provide the first set of hypermethylated genes with the potential to complement TCL1-mediated GC B-cell transformation and spread.

Renal clear-cell carcinoma: an ultrastructural study on the junctional complexes

Junctional complexes such as tight junctions, adherens junctions, and desmosomes play crucial roles in the structure and function of epithelial cells. These junctions are involved in increasing cell-cell contact and as well serve as signaling centers regulating multiple functions in epithelial cells. Carcinoma cell lines cultured in the laboratory generally lack junctional complexes. However, studies directed towards understanding the distribution of junctional complexes in human cancer tissues are lacking. In this study, we analyzed by electron microscopy the distribution of junctional complexes in patients diagnosed with renal clear-cell carcinoma. We found that both tight junctions and adherens junctions were drastically reduced in patients with cancer compared to normal tissues. Desmosomes were not detected in normal proximal tubules while distinctly present in cancer tissues. These results suggest that analysis of junctional complexes in human tumors should provide valuable information that might have prognostic and diagnostic value.

Geotechnical engineering properties of incinerator ash mixes

The incineration of solid waste produces large quantities of bottom and fly ash. Landfilling has been the primary mode of disposal of these waste materials. Shortage in landfill space and the high cost of treatment have, however, prompted the search for alternative uses of these waste materials. This study presents an experimental program that was conducted to determine the engineering properties of incinerator ash mixes for use as construction materials. Incinerator ash mixes were tested as received and around optimum compacted conditions. Compaction curves, shear strength, and permeability values of fly ash, bottom ash, and their various blends were investigated. Bottom ash tends to achieve maximum dry density at much lower water content than does fly ash. The mixes displayed a change in their cohesion and friction angle values when one of the two mix components was altered or as a result of the addition of water. The permeability of bottom ash is quite comparable to that of sand. The permeability of fly ash lies in the range of those values obtained for silts and clays. A 100% bottom ash compacted at the optimum water content has a lower density value and yields a higher friction angle and cohesion values than most construction fills. This would encourage the use of bottom ash as a fill or embankment material because free drainage of water will prevent the buildup of pore water pressures.

Interferon-alpha induces dendritic cell differentiation of CML mononuclear cells in vitro and in vivo

The ability of interferon-alpha (IFN-alpha) to induce dendritic cell (DC) differentiation in chronic myeloid leukemia (CML) was evaluated. Peripheral blood mononuclear cells from CML patients cultured with IFN-alpha and granulocyte-macrophage colony-stimulating factor (GM-CSF) developed a dendritic morphology. Fluorescence in situ hybridization demonstrated that the DCs harbored the bcr/abl translocation. The DCs prepared with IFN-alpha/GM-CSF expressed significantly higher levels of class I and II HLA than those grown in interleukin-4 (IL-4) and GM-CSF. The DCs prepared from newly diagnosed CML patients using IFN-alpha/GM-CSF expressed immunoregulatory proteins at levels comparable to normal DCs. In contrast, DCs cultured from CML patients who did not achieve a cytogenetic response to IFN-alpha expressed significantly lower levels of class I HLA, CD40, CD54, CD80 and CD86 than normal DCs. The expression of CD86 by CML DCs was enhanced when they were cultured with IFN-alpha/IL-4/GM-CSF, or when IFN-alpha/GM-CSF-treated cells were induced to mature by CD40 ligand. The DCs from IFN-alpha failures were less stimulatory than normal DCs in the allogeneic mixed leukocyte reaction. CML patients who had a cytogenetic response to IFN-alpha initially had low numbers of bone marrow DCs that increased significantly with treatment, while nonresponders had more prevalent DCs at baseline that showed no consistent change with treatment. Therefore, IFN-alpha can induce DC differentiation from CML progenitor cells both in vitro and in vivo. The therapeutic activity of IFN-alpha in CML may be due to its ability to stimulate the generation of DCs that can present CML-specific antigens. Resistance to IFN-alpha may result when DC differentiation becomes impaired.

Cytokeratin 20 as an immunocytochemical marker for detection of urothelial carcinoma in atypical cytology: preliminary retrospective study on archived urine slides

Previous studies have shown that expression of cytokeratin 20 (CK20), a constituent of intermediate filaments, is increased in malignant versus benign urine samples. To evaluate whether immunocytochemical staining of CK20 on archived urine slides could be used as a potential adjunct marker for triage of atypical urine cytology, we analyzed a total of 77 archived urine slides obtained from a spectrum of patients with various risks of developing urothelial carcinoma. These patients were divided into four groups on the basis of initial urine cytologic results and subsequent follow-up biopsy findings; group 1 had negative results in both evaluations, whereas the results in group 4 were positive for both cytology and biopsy. Groups 2 and 3 had a diagnosis of atypical urine cytology; however, patients in group 3 had a positive follow-up biopsy, and patients in group 2 did not. The Papanicolaou-stained archived urine slides were destained and then restained immunocytochemically with monoclonal antibody against CK20. With 5% positively stained nonumbrella cells as a threshold, CK20 was positive in 94.4% of group 3 or 4 patients. In contrast, CK20 was positive in 27.3% of group 2 patients and in 10.5% of group 1 patients. The overall sensitivity and specificity for CK20 for the detection of urothelial carcinoma in this population of patients were 94.4% and 80.5%, respectively. This study demonstrated that immunocytochemical analysis of CK20 on archived urine slides could be used to triage atypical urine cytology into low- and high-risk categories and that CK20 might be a simple and useful early detection marker for urothelial carcinoma.

Prostate stem cell antigen is overexpressed in human transitional cell carcinoma

Prostate stem cell antigen (PSCA), a homologue of the Ly-6/Thy-1 family of cell surface antigens, is expressed by a majority of human prostate cancers and is a promising target for prostate cancer immunotherapy. In addition to its expression in normal and malignant prostate, we recently reported that PSCA is expressed at low levels in the transitional epithelium of normal bladder. In the present study, we compared the expression of PSCA in normal and malignant urothelial tissues to assess its potential as an immunotherapeutic target in transitional cell carcinoma (TCC). Immunohistochemical analysis of PSCA protein expression was performed on tissue sections from 32 normal bladder specimens, as well as 11 cases of low-grade transitional cell dysplasia, 21 cases of carcinoma in situ (CIS), 38 superficial transitional cell tumors (STCC, stages T(a)-T(1)), 65 muscle-invasive TCCs (ITCCs, stages T(2)-T(4)), and 7 bladder cancer metastases. The level of PSCA protein expression was scored semiquantitatively by assessing both the intensity and frequency (i.e., percentage of positive tumor cells) of staining. We also examined PSCA mRNA expression in a representative sample of normal and malignant human transitional cell tissues. In normal bladder, PSCA immunostaining was weak and confined almost exclusively to the superficial umbrella cell layer. Staining in CIS and STCC was more intense and uniform than that seen in normal bladder epithelium (P < 0.001), with staining detected in 21 (100%) of 21 cases of CIS and 37 (97%) of 38 superficial tumors. PSCA protein was also detected in 42 (65%) of 65 of muscle-invasive and 4 (57%) of 7 metastatic cancers, with the highest levels of PSCA expression (i.e., moderate-strong staining in >50% of tumor cells) seen in 32% of invasive and 43% of metastatic samples. Higher levels of PSCA expression correlated with increasing tumor grade for both STCCs and ITCCs (P < 0.001). Northern blot analysis confirmed the immunohistochemical data, showing a dramatic increase in PSCA mRNA expression in two of five muscle-invasive transitional cell tumors when compared with normal samples. Confocal microscopy demonstrated that PSCA expression in TCC is confined to the cell surface. These data demonstrate that PSCA is overexpressed in a majority of human TCCs, particularly CIS and superficial tumors, and may be a useful target for bladder cancer diagnosis and therapy.

Interleukin 2 gene therapy for prostate cancer: phase I clinical trial and basic biology

Twenty-four patients with locally advanced prostate cancer (CaP) were enrolled in a phase I clinical trial using gene-based immunotherapy. A functional DNA-lipid complex encoding the interleukin 2 (IL-2) gene (Leuvectin; Vical, San Diego, CA) was administered intraprostatically into the hypoecogenic tumor lesion, using transrectal ultrasound guidance. Two groups of patients having locally advanced tumors were enrolled to receive a treatment regimen composed of two serial intraprostatic injections of the IL-2 gene agent administered 1 week apart. The first groups of patients included radical prostatectomy candidates who subsequently underwent surgery after the completion of the treatment regimen. The second group consisted of patients who had failed a prior therapy. Prostate specimens of the treated areas were attained after treatment and compared with the transrectal biopsies performed at baseline to assess for any responses. IL-2 gene therapy was well tolerated, with no grade 3 or 4 toxic reactions occurring. The most commonly reported symptoms were mild hematuria, transient rectal bleeding, and perineal discomfort that are likely attributable to the injection itself. During the entire course of treatment, there were no significant changes in American Urologic Association (AUA) symptom scores, in hematologic disturbances, electrolyte imbalances, or hepatic functions. Evidence of systemic immune activation was observed after IL-2 gene therapy, based on an increase in the intensity of T cell infiltration seen on immunohistochemical analysis of tissue samples from the injected tumor sites, and based on increased proliferation rates of peripheral blood lymphocytes that were cocultured with patient serum collected after treatment. Furthermore, transient decreases in serum prostate-specific antigen (PSA) (responders) were seen in 16 of 24 patients (67%) on day 1. Fourteen of the patients persisted in this decrease to day 8 (58%). In eight patients the PSA level rose (nonresponders). More patients (9 to 10) in the group that failed prior therapy responded to the IL-2 gene injections (chi-square test, p = 0.04), and 6 of the 9 also had lower than baseline PSA levels at week 10 after treatment. To the best of our knowledge, this is the first clinical study of its kind aimed at exploring the role of IL-2-based gene therapy in CaP patients. This phase I trial demonstrated the safety of intraprostatic Leuvectin injection, with transient PSA-based responses seen after therapy.

Primary effusion lymphoma in an HIV-negative patient with no serologic evidence of Kaposi's sarcoma virus

Primary effusion lymphoma (PEL) is a newly described high-grade B cell lymphoma which develops in association with Kaposi's sarcoma-associated herpesvirus (KSV) in human immunodeficiency virus (HIV)-infected individuals. We hereby describe a very unusual presentation of PEL that developed in the abdominal cavity of an HIV negative, KSV negative patient with a 1-year history of refractory ascites due to alcohol-related liver cirrhosis. Possible factors aiding lymphomagenesis in the cirrhotic state are discussed.

Preoperative prostate needle biopsy p27 correlates with subsequent radical prostatectomy p27, Gleason grade and pathological stage

PURPOSE

Loss of p27 protein expression in radical prostatectomy specimens has been shown to be an adverse prognostic factor in patients with clinically localized prostate cancer. To our knowledge no studies have examined p27 expression in prostate needle biopsies. To test the potential predictive power of p27 in prostate biopsies we compared p27 expression in preoperative biopsies and matched prostatectomy specimens of patients with clinically localized prostate cancer.

MATERIALS AND METHODS

Matched biopsies and radical prostatectomy specimens from 44 patients were examined. Mean followup was 22.7 months (range 1 to 46). Tumors expressing less than 30% positive nuclei were classified as low expressors and tumors expressing greater than 30% positive nuclei were classified as high expressors of p27 protein.

RESULTS

Expression of p27 in prostate biopsies correlated significantly with subsequent p27 expression in radical prostatectomy specimens (p = 0.002). Sensitivity and specificity of biopsy p27 for predicting subsequent prostatectomy p27 were 87.5% and 88.9%, respectively (p <0.001). Univariate analysis showed that low expression of p27 in the biopsy correlated significantly with biopsy and prostatectomy Gleason score (p = 0.000 and 0.001, respectively), and final pathological stage (p = 0.028). Despite the small sample size and short followup, 36.4% of patients with low p27 expression had a biochemical recurrence compared to only 12.1% with high expression (hazards ratio 3.56). In addition, Kaplan-Meier analysis suggested that low p27 expression in prostate biopsies may be associated with a shorter time to recurrence, although this did not reach statistical significance (p = 0.081).

CONCLUSIONS

Expression of p27 in prostate biopsies can be used to predict the degree of expression in radical prostatectomy specimens. As loss of p27 protein expression in prostatectomy specimens has been shown to correlate with biochemical recurrence and shortened prostate specific survival, these results suggest that biopsy p27 may help identify high risk patients preoperatively.

Effects of long-term administration of vitamin D3 analogs to mice

This study explores the effects of chronic administration of vitamin D(3) compounds on several biological functions in mice. Knowledge of long-term tolerability of vitamin D(3) analogs may be of interest in view of their potential clinical utility in the management of various pathologies such as malignancies, immunological disorders and bone diseases. Four unique vitamin D(3) analogs (code names, compounds V, EO, LH and LA) and 1,25-dihydroxyvitamin D(3) (1, 25(OH)(2)D(3)) were administered i.p. for 55 weeks to Balb/c mice. Each analog had previously been shown to have potent in vitro activities. After 55 weeks of administration, the mice had a profound decrease in their serum levels of interleukin-2 (IL-2). Likewise, several analogs depressed serum immunoglobulin G concentrations (compounds LH and LA), but levels of blood lymphocytes and splenic lymphocyte subsets (CD4, CD8 and CD19) were not remarkably depressed. The percent of committed myeloid hematopoietic stem cells was 4- to 5-fold elevated in the bone marrow of the mice that received analogs LH and V; nevertheless, their peripheral blood white and red cell counts and platelets were not significantly different in any of the groups. The mice that received 1,25(OH)(2)D(3) had a decrease in bone quantity and quality with a decrease in cross-sectional area and cortical thickness, and a 50% reduction in both stiffness and failure load compared with the control group. In contrast, the cohort that received a fluorinated analog (compound EO) developed bones with significantly larger cross-sectional area and cortical thickness as well as stronger mechanical properties compared with the control group. At the conclusion of the study, body weights were significantly decreased in all experimental mice. Their blood chemistries were normal. Extensive gross and microscopic autopsy analyses of the mice at the conclusion of the study were normal, including those of their kidneys. In conclusion, the vitamin D(3) analogs were fairly well tolerated. They did suppress immunity as measured by serum IL-2 and may provide a means to depress the immune response after organ transplantation and for autoimmune diseases. Use of these analogs prevented the detrimental effects of vitamin D(3) administration on mechanical and geometric properties of bone, while one analog (compound EO) actually enhanced bone properties. These results suggest that long-term clinical trials with the analogs are feasible.

CXC and CC chemokine receptors on coronary and brain endothelia

BACKGROUND

Chemokine receptors on leukocytes play a key role in inflammation and HIV-1 infection. Chemokine receptors on endothelia may serve an important role in HIV-1 tissue invasion and angiogenesis.

MATERIALS AND METHODS

The expression of chemokine receptors in human brain microvascular endothelial cells (BMVEC) and coronary artery endothelial cells (CAEC) in vitro and cryostat sections of the heart tissue was determined by light and confocal microscopy and flow cytometry with monoclonal antibodies. Chemotaxis of endothelia by CC chemokines was evaluated in a transmigration assay.

RESULTS

In BMVEC, the chemokine receptors CCR3 and CXCR4 showed the strongest expression. CXCR4 was localized by confocal microscopy to both the cytoplasm and the plasma membrane of BMVEC. In CAEC, CXCR4 demonstrated a strong expression with predominantly periplasmic localization. CCR5 expression was detected both in BMVEC and CAEC but at a lower level. Human umbilical cord endothelial cells (HUVEC) expressed strongly CXCR4 but only weakly CCR3 and CCR5. Two additional CC chemokines, CCR2A and CCR4, were detected in BMVEC and CAEC by immunostaining. Immunocytochemistry of the heart tissues with monoclonal antibodies revealed a high expression of CXCR4 and CCR2A and a low expression of CCR3 and CCR5 on coronary vessel endothelia. Coronary endothelia showed in vitro a strong chemotactic response to the CC chemokines RANTES, MIP-1alpha, and MIP-1beta.

CONCLUSIONS

The endothelia isolated from the brain display strongly both the CCR3 and CXCR4 HIV-1 coreceptors, whereas the coronary endothelia express strongly only the CXCR4 coreceptor. CCR5 is expressed at a lower level in both endothelia. The differential display of CCR3 on the brain and coronary endothelia could be significant with respect to the differential susceptibility of the heart and the brain to HIV-1 invasion. In addition, CCR2A is strongly expressed in the heart endothelium. All of the above chemokine receptors could play a role in endothelial migration and repair.

Evidence for clonal outgrowth of androgen-independent prostate cancer cells from androgen-dependent tumors through a two-step process

Prostate cancers require androgen for growth but progress to an androgen-independent stage under the selective pressure of androgen ablation therapy. Here we describe a novel human prostate cancer xenograft (LAPC-9) propagated by serial passage in male severe combined immunodeficient mice that expresses prostate-specific antigen and wild-type androgen receptor. In response to castration, LAPC-9 cells undergo growth arrest and persist in a dormant, androgen-responsive state for at least 6 months. After prolonged periods of androgen deprivation, spontaneous androgen-independent outgrowths develop. Thus, prostate cancers progress to androgen independence through two distinct stages, initially escaping dependence on androgen for survival and, subsequently, for growth. Through the use of serial dilution and fluctuation analysis, we provide evidence that the latter stage of androgen independence results from clonal expansion of androgen-independent cells that are present at a frequency of about 1 per 10(5)-10(6) androgen-dependent cells. We conclude that prostate cancers contain heterogeneous mixtures of cells that vary in their dependence on androgen for growth and survival and that treatment with antiandrogen therapy provides selective pressure and alters the relative frequency of these cells, thereby leading to outgrowths of androgen-independent cancers.

Loss of p73 gene expression in leukemias/lymphomas due to hypermethylation

The p73 gene, a member of the p53 family, is a new candidate tumor suppressor gene. To investigate the possibility of genetic alteration of p73 in leukemia and lymphoma, we examined 55 cell lines and 39 patient samples together with 17 nonhematopoietic cancer cell lines. Gene expression of p73 was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in cell lines (5 of 7 pre B/B-acute lymphoblastic leukemia [ALL], 13 of 21 T-ALL/lymphoblastic lymphomas [LBL], 9 of 10 B-non-Hodgkin's lymphomas [B-NHL], 8 of 9 acute myelogenous leukemias [AML], 2 of 2 T-NHL, 3 of 3 multiple myeloma), and in patient samples (16 of 23 pre B-ALL, 5 of 8 T-ALL/LBL, 5 of 8 B-NHL). PCR-single-strand conformation polymorphism (SSCP) of cDNAs showed no mutation in 43 p73-expressing cell lines within the regions that corresponded to the 5 mutational hotspots of the p53 gene. Neither homologous deletion nor rearrangement of the p73 gene were found by Southern blot analysis in any of the cell lines that lack expression of p73. In contrast to prior published data, analysis of a polymorphic site showed that the p73 gene was expressed biallelically in cell lines and normal peripheral blood. Notably, the p73-negative cell lines were hypermethylated at a CpG island in the 5' untranslated region of the p73 mRNA, and treatment of these cell lines with 5-azacytidine (5-AC), a demethylation reagent, induced p73 expression. Taken together, we found that a sizable proportion (32%) of ALL/B-NHL cell lines and primary tumors had negligible or limited expression of the p73 gene associated with hypermethylation of the gene. These findings suggest that silencing of the p73 gene by hypermethylation may contribute to development and/or progression of lymphoid neoplasms.

Novel 20-epi-vitamin D3 analog combined with 9-cis-retinoic acid markedly inhibits colony growth of prostate cancer cells

BACKGROUND

1,25 dihydroxyvitamin D3 (1,25D) and retinoids may play an important role in preventing progression of prostate cancer.

METHODS

We examined the ability of four novel 20-epi-vitamin D3 analogs (CB1093, KH1060, KH1266, and CB1267), either alone or in combination with 9-cis retinoic acid (RA) to inhibit colony growth of a human prostate cancer cell line, LNCaP, using soft agar as well as bone marrow stroma. Also, the effect of these analogs on the cell cycle and expression of Ki-67, p21(waf-1), and p27(kip1) in LNCaP cells was examined.

RESULTS

The analog CB1267 was the most potent, with 8 x 10(-10) M of the analog inhibiting 50% colony growth (ED50) of LNCaP. 9-cis-RA also inhibited colony growth of LNCaP (ED50, 5 x 10(-7) M). Combined, CB1267 and 9-cis-RA synergistically inhibited colony growth and significantly increased the number of LNCaP cells in G0/G1 phase. Cell cycle arrest was associated with increased levels of p21(waf-1) and p27(kip1) and decreased expression of Ki-67 protein. Pulse-exposure to this combination (5 x 10(-8) M) irreversibly inhibited colony growth, both in soft agar and on normal human bone marrow stroma.

CONCLUSIONS

Combination of a new vitamin D3 analog (CB1267) and a retinoid (9-cis-RA) potently inhibited colony formation of LNCaP prostate cancer cells in vitro, suggesting further studies in animal models. This combination may afford an interesting therapeutic approach to low-burden prostate cancer.

20-Cyclopropyl-cholecalciferol vitamin D3 analogs: a unique class of potent inhibitors of proliferation of human prostate, breast and myeloid leukemia cell lines

We have synthesized and studied the ability of a series of nine novel 1,25 dihydroxyvitamin D3 [1,25(OH)2D3] analogs to inhibit clonal growth of myeloid leukemic cells (HL,60), prostate (LNCaP, PC-3 and DU-145) and breast (MCF-7) cancers cells. DU-145 cells were actively resistant to compounds (cmpd) with all of these modifications, but when we removed C-19 (E, 1,25-Dihydroxy-23E-ene-26,27-hexafluoro-19-nor-20-cyclopropy l- cholecalciferol) an analog resulted that was inhibitory against all three prostate cell lines, breast and HL-60 cell lines. Further analysis showed that pulse exposure (3 days, 10(-7) M) to this analog was enough to inhibit clonal growth of PC-3 cell by 50%. Furthermore, cmpd E increased the number of PC-3 cells in G1 and decreased the number in S phase. 1,25(OH)2D3 mediates its biological activities through specific binding to the vitamin D3 receptor (VDR) and subsequent association with vitamin D3 response elements (VDRE) in genes modulated by 1,25(OH)2D3. Several novel vitamin D3 cmpds have recently been identified which have 5- to 1000-fold greater abilities to induce differentiation and to inhibit proliferation of prostate cancer, breast cancer and HL-60 leukemic blast cells as compared to the parental 1,25(OH)2D3. To clarify the mechanism by which nine of these vitamin D3 analogs mediate their remarkably potent biological activities, we have investigated their abilities in PC-3 prostate cancer cells to transactivate a chroramphenicol acetyl transferase (CAT) reporter gene containing a VDRE from the human osteocalcin gene attached to a thymidine kinase minimal promoter. Dose-response studies of Cmpd E showed that in serumless culture conditions, transactivation of the VDRE-CAT was stronger than cmpd J [1,25(OH)2D3]. Then, we investigated the effects of vitamin D3 cmpd J in mice. Our data showed the growth inhibitory action of the vitamin D3 cmpd E in prostate cancer cell line (PC-3) was stastically superior to the non-treatment group in terms of tumor size and tumor weight in mice. In summary, this is the first report of a potent series of 20-cyclopropyl-cholecalciferol vitamin D3 analogs with the ability to inhibit proliferation of LNCaP, PC-3, DU-145, MCF-7 and HL-60 cell lines. These cmpds may mediate their potent anti-proliferative activities through a cell cycle arrest pathway.

Cyclin A1 expression in leukemia and normal hematopoietic cells

Human cyclin A1 is a newly cloned, tissue-specific cyclin that is prominently expressed in normal testis. In this study, we showed that cyclin A1 was highly expressed in a subset of leukemia samples from patients. The highest frequency of cyclin A1 overexpression was observed in acute myelocytic leukemias, especially those that were at the promyelocyte (M3) and myeloblast (M2) stages of development. Cyclin A1 expression was also detected in normal CD34(+) progenitor cells. The expression of cyclin A1 increased when these cells were stimulated to undergo myeloid differentiation in vitro. Taken together, our observations suggest that cyclin A1 may have a role in hematopoiesis. High levels of cyclin A1 expression are especially associated with certain leukemias blocked at the myeloblast and promyelocyte stages of differentiation.

Combination therapy of a vitamin D3 analog and all-trans-retinoic acid: effect on human breast cancer in nude mice

BACKGROUND

Vitamin D3 analogs and all-trans-retinoic acid (ATRA) are able to inhibit the growth of a variety of malignant cells.

MATERIAL AND METHODS

We examined the ability of three vitamin D3 analogs to inhibit the growth of a human mammary cancer cell line (MCF-7) in Beige Nude xid (BNX) mice either alone or with ATRA. Vitamin D3 analogs 1,25 dihydroxyvitamin D3 (code name, compound C), 1,25 (OH)2-16-ene-23-yne-19-nor-26,27-F6-D3 (compound LH) and 24a,26a,27a,-trihomo-22,24-diene-1,25(OH)2D3 (EB1089) were used.

RESULTS

The antitumor effect of ATRA alone was greater than that of either of the vitamin D3 analogs alone, and an additive effect was observed when a vitamin D3 analog and ATRA were administered together. EB1089 was the most potent vitamin D3 analog; and EB1089 plus ATRA was the most potent combination decreasing the tumor mass nearly 3-fold compared to tumors of diluent control mice. None of the animals became hypercalcemic. Their complete blood counts, serum electrolyte analysis as well as their liver and renal functions were all fairly similar and within the normal range.

CONCLUSION

This combination of a vitamin D3 analog and ATRA has the potential to be an adjuvant therapy for breast cancer.

Novel vitamin D3 analog (CB1093) when combined with paclitaxel and cisplatin inhibit growth of MCF-7 human breast cancer cells in vivo

Vitamin D3 compounds paclitaxel (Taxol) and cisplatin (CDDP, cis-diamminodichloroplatinum) inhibit growth of a variety of malignant cells. We examined the ability of a novel 20-epi-vitamin D3 analog (code name, CB1093), Taxol and CDDP either alone or in combination to inhibit the growth of a human mammary cancer (MCF-7) growing in BNX triple immunodeficient mice. Tumors in control animals demonstrated infiltrating poorly differentiated adenocarcinomas. At the doses chosen, the antitumor effect of Taxol alone was greater than that of either CB1093 or CDDP alone; and additive effects were observed when either CB 1093 + Taxol or CB 1093 + CDDP + Taxol were administered together. The combination of CB 1093 + Taxol + CDDP was most potent, inhibiting tumor weights by nearly 83% compared to control tumors and producing extensive necrosis of the remaining tumor mass. No additive effect occurred by combining either CB1093 + CDDP or Taxol + CDDP compared to Taxol alone. For all cohorts, their complete hematopoietic blood counts, serum electrolyte analyses including serum calciums as well as their liver and renal functions were within the normal range. Extensive histological analyses of the liver, spleen, kidneys, bone marrow, skin and subcutaneous fat pads from these mice showed no abnormalities. In summary, combined therapy with CB1093 (a potent vitamin D3 analog), Taxol and CDDP, which have non-cross reactive toxicities, holds promise in the treatment of patients with breast cancer.

Seroprevalence of HHV-8 antibodies in HIV-positive homosexual men without Kaposi's sarcoma and their clinical follow-up

Human herpesvirus 8 (HHV-8) has been associated with Kaposi's sarcoma (KS). Because KS is most frequently seen in HIV-positive homosexual men, we retrospectively evaluated the seroprevalence of HHV-8 in this risk group and compared the clinical history and clinical course of the HHV-8-negative and HHV-8-positive groups. The study was performed by analyzing banked serum samples from asymptomatic HIV-positive men. HHV-8 seropositivity was determined by an indirect immunofluorescence test. A total of 56% of patients (42/75) were seropositive for anti-HHV-8 IgG antibodies as opposed to 12% of 40 age-matched HIV-negative controls. Median CD4 counts at study entry were significantly lower in the HHV-8-positive group than in the HHV-8-negative group (520 vs 686); however, the percentage decrease during a 30-month follow-up did not differ significantly. KS developed in two patients during follow-up; both were HHV-8-positive and had CD4 counts of less than 200/microL at the time of clinical manifestation. One HHV-8-positive patient in whom AIDS developed died of infectious complications. The longest follow-up in the HHV-8-positive cohort without development of KS was 81 months. We conclude that HHV-8 has a high seroprevalence in asymptomatic, homosexual, HIV-positive persons. An HHV-8 infection can precede the development of KS by many years. Immunosuppression below a certain threshold may trigger the clinical manifestation of KS.

Multiple myeloma: the cells of origin--a two-way street

Multiple myeloma results from an interplay between the monoclonal malignant plasma cells and supporting nonmalignant cells in the bone marrow. Recent studies suggest that the final transforming event in this B cell disorder occurs at a late stage of B cell differentiation based on the characteristics of the immunoglobulin genes expressed by the malignant clone as well as surface markers present on the tumor cells. Recently, an increasing pathogenic role in this malignancy by the nonmalignant cells in the bone marrow has been suggested by several studies. Specific infection of these supporting cells by the recently identified Kaposi's sarcoma-associated herpes virus (KSHV) suggests a novel mechanism by which this nonmalignant population may lead to the development of this B cell malignancy and support its growth.

Mutational analysis of the hMSH2 gene in a wide variety of tumors

The hMSH2 gene participates in DNA mismatch repair and its mutation can result in genetic instability of the human genome which is an important feature of tumorigenesis. In this study, genetic alterations of the hMSH2 gene were examined in 43 ovarian, 36 non-small cell lung (NSCL), 31 poorly differentiated gastric, 15 endometrial, and 11 colon cancers, nine gastric cancer cell lines, 41 adult T-cell leukemias (ATLs), two ATL cell lines, and 37 non-Hodgkin's lymphomas (NHLs), using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique. Microsatellite instability (MSI) was also investigated for ovarian, NSCL, and colon cancers. The incidence of MSI was 1/36 (3%) for NSCL, 2/23 (9%) for ovarian, and 1/11 (9%) for colon cancers. Missense base changes of the hMSH2 gene were identified in two gastric cancer patients (ATG to ATA resulting in Met changing to Ile at codon 688 in exon 13 and ACA to GCA resulting in Thr changing to Ala at codon 803 in exon 14). These mutations were found in samples with no MSI. One ovarian and one gastric cancer, and six ATL samples showed two types of polymorphisms of hMSH2 (CTT to TTT resulting in Leu changing to Phe at codon 390 in exon 7 and CAG to AAG resulting in Gin to Arg at codon 419 in exon 7). Our data suggest that MSI and hMSH2 mutations are uncommon in sporadic tumors.

Combination of a potent 20-epi-vitamin D3 analogue (KH 1060) with 9-cis-retinoic acid irreversibly inhibits clonal growth, decreases bcl-2 expression, and induces apoptosis in HL-60 leukemic cells

All-trans retinoic acid (RA) is the first highly effective differentiation-inducing agent for remission induction in patients with acute promyelocytic leukemia. However, remissions are short-lived because the treatment fails to induce complete differentiation and fails to eradicate the malignant clone. To eliminate rapidly the malignant clone, in analogy with aggressive chemotherapy, the combination of potent differentiation- and apoptosis-inducing drugs working through different receptors and signal pathways may be useful. The active form of vitamin D3 (1,25-dihydroxyvitamin D3; 1,25(OH)2D3) inhibits proliferation and induces differentiation of myeloid leukemic cells. The 9-cis-RA, unlike all-trans-RA which binds only retinoic acid receptors, is a high affinity ligand for both retinoic acid receptors and retinoid X receptors. The aim of this study was to evaluate the therapeutic potential of combining a vitamin D(3) analogue, 20-epi-22-oxa-24a,26a,27a-tri-homo-1alpha,25(OH) 2D, (KH 1060), which belongs to the family of potent 20-epi-1,25(OH),D3 analogues, with 9-cis-RA by assessing their effects on the proliferation, differentiation, and apoptosis of the human leukemia cell line HL-60 in vitro. Our data show that KH 1060 alone is a very potent inhibitor of clonal proliferation of HL-60, but this effect is reversible, and that 9-cis-RA alone is a weak inhibitor of clonal proliferation of HL-60 cells. In contrast, the combination of KH 1060 and 9-cis-RA synergistically and irreversibly inhibited the clonal proliferation of HL-60 cells and induced apoptosis, as detected by morphological changes and DNA fragmentation. This combination also affected the expression of apoptosis-related genes. The bcl-2 protein became nearly undetectable, and expression of bax protein increased slightly (the bax:bcl-2 ratio was 14-fold higher than in untreated cells). Differentiation of treated HL-60 cells was assessed by their ability to produce superoxide, as measured by reduction of nitro blue tetrazolium, positive staining for alpha-naphthyl acetate esterase, phagocytosis, morphology, and analysis of membrane-bound differentiation markers with two-color immunofluorescence. Treatment with the combination of KH 1060 and 9-cis-RA was a potent inducer of differentiation of HL-60, with the cells developing a myelomonocytic phenotype. In summary, our data demonstrate that the combination of both KH 1060 and 9-cis-RA irreversibly and synergistically inhibited clonal growth, induced differentiation and apoptosis of HL-60 cells concomitantly with a very marked decreased expression of bcl-2, and increased the bax:bcl-2 ratio. This drug combination may have important therapeutic significance.

Nodular lymphocyte-predominant Hodgkin's disease associated with large-cell lymphoma: analysis of Ig gene rearrangements by V-J polymerase chain reaction

The clonality of nodular lymphocyte-predominant Hodgkin's disease (NLPHD) and the relationship to composite or sequential large-cell lymphomas (LCLs) is poorly understood. Clonal Ig heavy-chain gene rearrangements (lgHGR) have infrequently been observed in NLPHD by Southern hybridization. The goals of this study were (1) to determine if IgHGR could be identified by polymerase chain reaction (PCR) techniques in the LCL associated with NLPHD; (2) to determine if the lgHGR identified in the LCL could also be found in the associated NLPHD; and (3) to determine if Epstein-Barr virus (EBV) played a role a role in histologic progression to LCL. Using consensus primers to conserved regions in the lgH variable (V) and joining (J) region genes, we analyzed formalin-fixed paraffin-embedded sections from the biopsies of 25 patients referred to the National Cancer Institute (NCI) registry for NLPHD and LCL using both single-step and seminested V-J PCR. The histologically aggressive component was further subclassified as frank LCL or as L&H-cell-rich, but not fulfilling criteria for LCL. Matched samples representing both NLPHD and aggressive components were available in 13 cases. In 12 cases, only one component was available (aggressive, n = 8; NLPHD, n = 4). In addition, we also amplified, with 32P labeling, 12 cases of NLPHD without associated LCL. Two clonal IgHGR were identified in 29 cases (7%) of typical NLPHD, both of which were associated with LCL containing a similar sized band by PCR. The clonal identity of the bands in the NLPHD and associated LCL was confirmed by sequencing the products in these two cases. Eight of 10 cases (80%) of LCL associated with NLPHD contained a clonal band by this technique. By contrast, none of the cases classified as L&H-cell-rich contained an IgHGR. The single-step and seminested PCR methods produced identical results. All clonal LCLs were studied for EBV sequences by in situ hybridization using the EBER1 probe, and were negative. We conclude that the LCLs associated with NLPHD are clonal B-cell malignancies. However, by these methods, the same clone can be identified in only a minority of cases of NLPHD and LCL. EBV does not appear to play a role in histologic progression. Moreover, our results suggest that many cases suspected of being LCL may actually represent NLPHD with increased numbers of L&H cells. In histologically equivocal cases, the diagnosis of LCL should be reserved for those cases in which a clonal B-cell neoplasm can be demonstrated.

Heparin-binding secretory transforming gene (hst) facilitates rat lactotrope cell tumorigenesis and induces prolactin gene transcription

We have shown previously that human prolactinomas express transforming sequences of the heparin-binding secretory transforming gene (hst) which encodes fibroblast growth factor-4 (FGF-4). To elucidate the role of hst in pituitary tumorigenesis we treated primary rat pituitary and pituitary tumor cell cultures with recombinant FGF-4 and also stably transfected pituitary cell lines with full-length human hst cDNA. Transfectants were screened for hst mRNA expression and FGF-4 production. FGF-4 (0.1-50 ng/ml) caused a dose-dependent 2.5-fold increase of prolactin (PRL) secretion (P < 0.001) in GH4 cells and up to 60% (P < 0.05) in primary cultures, while decreasing growth hormone release (P < 0.001). GH4 hst transfectants displayed markedly enhanced basal PRL secretion (threefold, P < 0.001) and also proliferated faster (P < 0.001). FGF-4 treatment of wild-type GH4 cells, transiently transfected with an expression construct (rPRL.luc) containing a luciferase reporter driven by the rPRL promoter, resulted in a dose-dependent increase of up to 3.3-fold in PRL transcriptional activity. Tumors derived from in vivo subcutaneous injection of GH4 hst-transfected cells strongly expressing FGF-4 grew more aggressively as assessed by histologic invasiveness and proliferating cell nuclear antigen staining (P < 0.01). The results indicate that hst overexpression mediates lactotrope tumor growth and potently stimulates PRL synthesis. Thus, hst may directly facilitate prolactinoma development via paracrine or autocrine action of its secreted protein, FGF-4.