bluuebunny/crossref_metadata_2025 huggingface dataset:
Restoration of natural legacies of fire in European boreal forests: an experimental approach to the effects on wood-decaying fungi
Authors: Junninen Kaisa , Kouki Jari , Renvall Pertti
Published: March 2008

Effective fire suspension in Fennoscandian boreal forests has caused a number of species to become threatened. To compensate for the negative ecological impacts of fire elimination, prescribed burning of forests as a restoration method has been introduced recently. We studied the effects of controlled burning on assemblages of wood-decaying polypores (Basidiomycota), including red-listed species, in a large-scale field experiment in Finland. A total of 24 forest sites were included in the factorial study design with two factors: logging and burning. The presence of polypore fruiting bodies was documented 1 year before the treatments, and 1 and 4 years after the treatments. Over 11 000 observations of 104 species of polypores were made. Change in the fungal species composition due to logging and burning was clear after 4 years. At the species level, the responses to logging and fire varied depending on the species. Treatments increased fruiting of pioneer decayers; however, most red-listed species seemed to suffer. Thus, prescribed burning does not offer immediate benefits for most red-listed species. In unlogged forests, the restorative effects of fire are likely to be seen later as the death and decay processes of trees continue and provide more resources for polypores.
The importance of catchment slope to soil water N and C concentrations in riparian zones: implications for riparian buffer width
Authors: Hazlett P. , Broad K. , Gordon A. , Sibley P. , Buttle J. , Larmer D.
Published: March 2008

Buffer zones are an important component of forest-management strategies and are thought to reduce the impact of nutrients released after harvesting on water quality. Conceptually, steep slopes have shorter water residence times than shallow slopes, have a reduced capacity to moderate water quality, and therefore, require wider buffers. Carbon and N concentrations in riparian zone shallow soil water at 30 cm depth and lake water were measured on shallow and steep slopes at the Esker Lakes Research Area in northeastern Ontario to determine if nutrient concentrations were correlated to catchment terrain attributes. Field measured slope, slope class obtained from a triangular irregular network model, and upslope contributing area and topographic index calculated from a digital elevation model were calculated for each sampling location. Modeled terrain properties, including those currently used during forest-management planning, were not significantly correlated with soil water N and C concentrations, whereas only dissolved organic carbon levels were significantly greater on field measured steep slopes. Forest species composition and soil N levels were positively correlated with soil water N concentrations. These results from the undisturbed boreal ecosystem highlight the potential limitation of using only catchment slope as a tool for prescribing riparian buffers during harvesting when considering terrestrial nutrient export.
Growth, resource storage, and adaptation to drought in California and eastern Mediterranean oak seedlings
Authors: Grünzweig José M. , Carmel Yohay , Riov Joseph , Sever Nava , McCreary Douglas D. , Flather Curtis H.
Published: March 2008

Low recruitment of new plants as currently observed in several California oak species might partly result from insufficient storage of vital resources (reduced ability to regrow after disturbance) or from low adaptation to environmental stress, such as drought. We conducted two studies under divergent environmental conditions to compare seedlings of California oaks with ecologically equivalent species from the eastern Mediterranean region, where recruitment has been substantial over the past 25–30 years. Resource concentrations (nonstructural carbohydrates and nitrogen) in taproots and the ratio of root resource content to shoot biomass did not provide evidence that Californian oak seedlings have smaller reserves for resprouting than eastern Mediterranean species in these studies. However, we observed lower seedling survival among California species, when compared with Mediterranean species, under conditions of higher drought stress. In the California deciduous Quercus douglasii Hook. & Arn., water-use efficiency as measured by leaf gas exchange and leaf δ13C was lower compared with its Mediterranean equivalent Quercus ithaburensis Decne. In addition, stomatal conductance in the California evergreen Quercus agrifolia Née appeared to be less sensitive to vapor pressure deficit than in its Mediterranean equivalent Quercus calliprinos Webb. Our results suggest lower adaptation to drought in the California species tested here as compared with Mediterranean species, which will negatively impact recruitment of oaks from California under the currently drier soil conditions.
Effects of riparian forest thinning by two types of mechanical harvest on stream fish and habitat in northern Minnesota
Authors: Hemstad Nathaniel A. , Merten Eric C. , Newman Raymond M.
Published: March 2008

The response of fish communities and stream habitat to four riparian harvest treatments was studied in north-central Minnesota to determine if riparian harvest with two different harvest systems degrades stream systems. Treatments included control (no harvest), riparian control, cut-to-length riparian thin, and tree length riparian thin. Fish and habitat data were collected from 50 m reaches above, within, and downstream of each treatment 1 year preharvest (1997) and 3 years postharvest (1998–2000). Repeated measures analysis revealed few effects due to treatment; however, there was a 6%–10% significant reduction in canopy cover. Percent fine sediments increased significantly (15%) system-wide following forest harvest and persisted through 2000. This increase in fine sediments was correlated with a decrease in fish biotic integrity (r = –0.31). Habitat and fish variables were influenced more by year-to-year variation than by harvest treatment, suggesting that factors operating at a broader basin-wide scale may influence fish and habitat or mask any site-level harvest effects in this low-gradient stream system. Residual riparian basal areas ≥12.3m2/ha along reaches ≤200 m in length may be adequate to protect fish and habitat in these low-gradient streams, but basin-wide effects of harvest deserve more scrutiny.
Effect of cutting intensity on microenvironmental conditions and regeneration dynamics in yellow birch – conifer stands
Authors: Prévost Marcel
Published: March 2008

This paper presents the 5 year results of different cutting intensities (removal of 0%, 40%, 50%, 60%, and 100% of the basal area) applied in two mixed yellow birch ( Betula alleghaniensis Britt.) – conifer stands of eastern Quebec, Canada. Two sites 90 km apart were used: Armagh and Duchesnay. Each site had four replicates of the treatments in a randomized block design. The effect on light availability was similar in the two sites: the 0%, 40%, 50%, 60%, and 100% cuts transmitting a mean of 5%, 21%, 26%, 30%, and 94% of full light, respectively, during the first summer. Soil temperature increased only in the 100% cut (4−5 °C, maximum daily temperature). Soil disturbance during harvest was higher at Duchesnay than at Armagh, which clearly improved seedbed receptivity, particularly to yellow birch. After 5 years, treated areas contained 21 000 to 48 300 seedlings/ha at Duchesnay compared with 5500 – 10 500 seedlings/ha at Armagh. Significant losses of coniferous advance growth were observed at both sites, but a subsequent seedling recruitment occurred only at Duchesnay. Red spruce ( Picea rubens Sarg.) showed superior establishment in the 60% cut (4400 seedlings/ha) than under other cutting intensities (1600–2100 seedlings/ha), whereas balsam fir ( Abies balsamea (L.) Mill.) responded well to all partial cutting treatments. At both sites, pin cherry ( Prunus pensylvanica L.f.) was the main competing species in the 100% cut, whereas densities of the preestablished mountain maple ( Acer spicatum Lamb.) and striped maple ( Acer pensylvanicum L.) either remained the same or increased in the partial cuts.
Allometry and size structure of trees in two ancient snow forests in coastal British Columbia
Authors: Parish Roberta , Nigh Gordon D. , Antos Joseph A.
Published: March 2008

Shade-tolerant trees that start in the understory but ultimately reach the canopy persist through different microhabitat conditions during their ontogeny. We evaluate how the height to diameter ratio and the crown ratio (crown length/tree height) change during development and differ among four coniferous species ( Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes, Chamaecyparis nootkatensis (D. Don) Spach, Tsuga mertensiana (Bong.) Carrière, and Tsuga heterophylla (Ref.) Sarg.) in ancient forests. At two sites, we measured diameter, height, and height to the base of live crown for trees ≥4.0 cm diameter at breast height in four 0.25 ha plots. For each species, we constructed models of height based on diameter and crown length using part of the data for model development and part as the test data set. Models predicting tree height were effective for all species, and adding crown length considerably improved the prediction over diameter alone. The height to diameter ratio increased until the subcanopy and then decreased for two shade-tolerant species (A. amabilis and T. heterophylla) but decreased linearly throughout ontogeny for C. nootkatensis. Crown ratio increased as trees became larger except for C. nootkatensis, where the reverse occurred. Differences in allometric relationship among species reflect patterns of crown development and also suggest different approaches to a common structural constraint in these forests: heavy snow loads.
Rad9 Has a Functional Role in Human Prostate Carcinogenesis
Authors: Zhu Aiping , Zhang Charles Xia , Lieberman Howard B.
Published: March 2008

Prostate cancer is currently the most common type of neoplasm found in American men, other than skin cancer, and is the second leading cause of cancer death in males. Because cell cycle checkpoint proteins stabilize the genome, the relationship of one such protein, Rad9, to prostate cancer was investigated. We found that four prostate cancer cell lines (CWR22, DU145, LNCaP, and PC-3), relative to PrEC normal prostate cells, have aberrantly high levels of Rad9 protein. The 3′-end region of intron 2 of Rad9 in DU145 cells is hypermethylated at CpG islands, and treatment with 5′-aza-2′-deoxycytidine restores near-normal levels of methylation and reduces Rad9 protein abundance. Southern blot analyses indicate that PC-3 cells contain an amplified Rad9 copy number. Therefore, we provide evidence that Rad9 levels are high in prostate cancer cells due at least in part to aberrant methylation or gene amplification. The effectiveness of small interfering RNA to lower Rad9 protein levels in CWR22, DU145, and PC-3 cells correlated with reduction of tumorigenicity in nude mice, indicating that Rad9 actively contributes to the disease. Rad9 protein levels were high in 153 of 339 human prostate tumor biopsy samples examined and detectable in only 2 of 52 noncancerous prostate tissues. There was a strong correlation between Rad9 protein abundance and cancer stage. Rad9 protein level can thus provide a biomarker for advanced prostate cancer and is causally related to the disease, suggesting the potential for developing novel diagnostic, prognostic, and therapeutic tools based on detection or manipulation of Rad9 protein abundance. [Cancer Res 2008;68(5):1267–74]
Inhibition of the Ras-Net (Elk-3) Pathway by a Novel Pyrazole that Affects Microtubules
Authors: Wasylyk Christine , Zheng Hong , Castell Christelle , Debussche Laurent , Multon Marie-Christine , Wasylyk Bohdan
Published: March 2008

Net (Elk-3/SAP-2/Erp) is a transcription factor that is phosphorylated and activated by the Ras–extracellular signal-regulated kinase (Erk) signaling pathway and is involved in wound healing, angiogenesis, and tumor growth. In a cell-based screen for small molecule inhibitors of Ras activation of Net transcriptional activity, we identified a novel pyrazole, XRP44X. XRP44X inhibits fibroblast growth factor 2 (FGF-2)–induced Net phosphorylation by the Ras-Erk signaling upstream from Ras. It also binds to the colchicine-binding site of tubulin, depolymerizes microtubules, stimulates cell membrane blebbing, and affects the morphology of the actin skeleton. Interestingly, Combretastin-A4, which produces similar effects on the cytoskeleton, also inhibits FGF-2 Ras-Net signaling. This differs from other classes of agents that target microtubules, which have either little effect (vincristine) or no effect (docetaxel and nocodazole) on the Ras-Net pathway. XRP44X inhibits various cellular properties, including cell growth, cell cycle progression, and aortal sprouting, similar to other molecules that bind to the tubulin colchicine site. XRP44X has the potentially interesting property of connecting two important pathways involved in cell transformation and may thereby represent an interesting class of molecules that could be developed for cancer treatment. [Cancer Res 2008;68(5):1275–83]
Selective Inhibition of Histone Deacetylase 2 Silences Progesterone Receptor–Mediated Signaling
Authors: Biçaku Elona , Marchion Douglas C. , Schmitt Morgen L. , Münster Pamela N.
Published: March 2008

Several histone deacetylases (HDAC) are involved in estrogen receptor (ER)–mediated gene transactivation, and HDAC inhibitors have been reported to restore sensitivity to antihormonal therapy. The modulation of ER is the most promising approach to ER-expressing breast cancers. Recent studies further suggest a critical role of the progesterone receptor (PR) on ER signaling. Although HDAC inhibitors modulate ER, little is known about their effects on PR. We evaluated the roles of specific HDAC isoenzymes and their inhibition on both ER and PR signaling and their importance in response to endocrine therapy. The roles of individual HDAC isoenzymes on ER and PR expression and their functions were evaluated by depletion of select HDAC enzymes using siRNA or pharmacologic inhibition. Cotreatment of breast cancer cell lines with HDAC inhibitors and the antiestrogen, tamoxifen, resulted in synergistic antitumor activity with simultaneous depletion of both ER and PR. Selective inhibition of HDAC2, but not HDAC1 or HDAC6, was sufficient to potentiate tamoxifen-induced apoptosis in ER/PR-positive cells. Depletion of HDAC1 and HDAC6 was associated with down-regulation of ER but not PR. Only the selective depletion of HDAC2 siRNA down-regulated both ER and PR expression, and was sufficient to potentiate tamoxifen. Selective depletion of HDAC2 resulted in simultaneous depletion of ER and PR, and potentiated the effects of antihormonal therapy in ER-positive cells. A more effective pharmacologic inhibition of HDAC2 and evaluation of HDAC2 and PR as therapeutic targets or as predictive markers in hormonal therapy may be considered when combining HDAC inhibitors and hormonal therapy. [Cancer Res 2008;68(5):1513–9]
p21Waf1/Cip1 Expression by Curcumin in U-87MG Human Glioma Cells: Role of Early Growth Response-1 Expression
Authors: Choi Byeong Hyeok , Kim Chang Gun , Bae Young-Seuk , Lim Yoongho , Lee Young Han , Shin Soon Young
Published: March 2008

Curcumin, a natural compound, is a well-known chemopreventive agent with potent anticarcinogenic activity in a wide variety of tumor cells. Curcumin inhibits cancer cell proliferation in part by suppressing cyclin D1 and inducing expression of the cyclin-dependent kinase inhibitor p21Waf1/Cip1. Both p53-dependent and p53-independent mechanisms regulate p21Waf1/Cip1 expression, but the mechanism by which curcumin regulates p21Waf1/Cip1 expression remains unknown. Here, we report that transcription of the p21Waf1/Cip1 gene is activated by early growth response-1 (Egr-1) independently of p53 in response to curcumin treatment in U-87MG human glioblastoma cells. Egr-1 is a transcription factor that helps regulate differentiation, growth, and apoptosis in many cell types. Egr-1 expression is induced by curcumin through extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK), but not the p38, mitogen-activated protein kinase (MAPK) pathways, which mediate the transactivation of Elk-1. Transient expression of Egr-1 enhanced curcumin-induced p21Waf1/Cip1 promoter activity, whereas suppression of Egr-1 expression by small interfering RNA abrogated the ability of curcumin to induce p21Waf1/Cip1 promoter activity. In addition, stable knockdown of Egr-1 expression in U-87MG cells suppressed curcumin-induced p21 expression. Our results indicate that ERK and JNK MAPK/Elk-1/Egr-1 signal cascade is required for p53-independent transcriptional activation of p21Waf1/Cip1 in response to curcumin in U-87MG human glioblastoma cells. [Cancer Res 2008;68(5):1369–77]
Endosomal Proteases Influence the Repertoire of MAGE-A3 Epitopes RecognizedIn vivoby CD4+ T Cells
Authors: Marturano Jill , Longhi Renato , Russo Vincenzo , Protti Maria Pia
Published: March 2008

Little is known about the repertoire of MAGE-A3 CD4+ T-cell epitopes recognized in vivo by neoplastic patients and how antigen processing influences epitope formation. Here, we first show that MAGE-A3–specific CD4+ T cells are present in the blood of advanced melanoma patients. MAGE-A3111-125, MAGE-A3191-205, and MAGE-A3281-300 were recognized by 7, 6, and 5 of the 11 patients tested, respectively. MAGE-A3146-160 and MAGE-A3171-185 were also recognized in two and one cases, whereas no recognition of MAGE-A3161-175 and MAGE-A3243-258 was observed. Cytokines produced were mainly interleukin 5 and/or granulocyte macrophage colony-stimulating factor, suggesting impairment of productive polarized Th1 responses. Secondly, proteases inhibitors were used to modulate in vitro the recognition by CD4+ T-cells clones of dendritic cells loaded with MAGE-A3–expressing cell lysates. We found that formation of MAGE-A3111-125 depended on both leupeptin-sensitive and pepstatin-sensitive proteases. In contrast, we found that MAGE-A3161-175, which was never recognized ex vivo, was formed by leupeptin but destroyed by pepstatin-sensitive proteases. Collectively, our results show that (a) anti–MAGE-A3 CD4+ T-cell immunity develops in vivo in neoplastic patients and is focused toward immunodominant epitopes, (b) the response in advanced disease is skewed toward a Th2 type, and (c) endosomal/lysosomal proteases in dendritic cells influence the repertoire of the epitopes recognized. [Cancer Res 2008;68(5):1555–62]
Anti–Tumor Necrosis Factor Therapy Inhibits Pancreatic Tumor Growth and Metastasis
Authors: Egberts Jan-Hendrik , Cloosters Vera , Noack Andreas , Schniewind Bodo , Thon Lutz , Klose Stefanie , Kettler Bastian , von Forstner Corinna , Kneitz Christian , Tepel Jürgen , Adam Dieter , Wajant Harald , Kalthoff Holger , Trauzold Anna
Published: March 2008

Chronic inflammation has been implicated in the pathogenesis of many severe autoimmune disorders, as well as in diabetes, pulmonary diseases, and cancer. Inflammation accompanies most solid cancers including pancreatic ductal adenocarcinoma (PDAC), one of the most fatal cancers with surgery being the only curative therapeutic approach currently available. In the present work, we investigated the role of the major proinflammatory cytokine tumor necrosis factor α (TNFα) in the malignancy of PDAC cells in vitro and in vivo. In vitro, TNFα strongly increased invasiveness of Colo357, BxPc3, and PancTuI cells and showed only moderate antiproliferative effect. TNFα treatment of mice bearing orthotopically growing PDAC tumors led to dramatically enhanced tumor growth and metastasis. Notably, we found that PDAC cells themselves secrete TNFα. Although inhibition of TNFα with infliximab or etanercept only marginally affected proliferation and invasiveness of PDAC cells in vitro, both reagents exerted strong antitumoral effects in vivo. In severe combined immunodeficient mice with orthotopically growing Colo357, BxPc3, or PancTuI tumors, human-specific anti-TNF antibody infliximab reduced tumor growth and metastasis by about 30% and 50%, respectively. Importantly, in a PDAC resection model performed with PancTuI cells, we found an even stronger therapeutic effect for both anti-TNF compounds. Infliximab and etanercept reduced the number of liver metastases by 69% and 42%, respectively, as well as volumes of recurrent tumors by 73% and 51%. Thus, tumor cell–derived TNFα plays a profound role in malignancy of PDAC, and inhibition of TNFα represents a promising therapeutic option particularly in adjuvant therapy after subtotal pancreatectomy. [Cancer Res 2008;68(5):1443–50]
Co-Targeting Insulin-Like Growth Factor I Receptor and HER2: Dramatic Effects of HER2 Inhibitors on Nonoverexpressing Breast Cancer
Authors: Chakraborty Ashok K. , Liang Ke , DiGiovanna Michael P.
Published: March 2008

The insulin-like growth factor I receptor (IGFIR) and HER2 display important signaling interactions in breast cancer. We examined the effect of combinations of antagonists of these receptors using two human breast cancer cell lines: BT474 (HER2+, IGFIR low) and MCF7 (HER2 low, IGFIR high). In BT474 cells, growth was inhibited by HER2 antagonists but not by IGFIR antagonists; however, IGFIR antagonists enhanced the effect of HER2 inhibitors. In MCF7 cells, growth was inhibited by IGFIR antagonists but not by HER2 antagonists; however, HER2 antagonism enhanced the effect of IGFIR inhibitors. Synergistic inhibition of soft agar growth was also observed. Although HER2 and IGFIR antagonists individually only minimally affected cell cycle, their combination gave a small enhancement of their effects. No single receptor-targeting drug was capable of inducing apoptosis, but combining antagonists of both receptors induced a dramatic degree of apoptosis in both cell lines. Induction of apoptosis was most striking in MCF7 cells using a Herceptin/IGFIR antagonist combination despite these cells being HER2 nonoverexpressing. Toward understanding the mechanism of these effects, we detected coassociation IGFIR and HER2 in both cell lines. Specific inhibitors of one of these receptors could cross-inhibit the activity of the other. Targeting both receptors gave the maximal inhibition of their downstream extracellular signal-regulated kinase 1/2 and AKT signaling pathways. Hence, such drug combinations may be clinically useful and may be beneficial even in tumors in which single drugs are inactive, as exemplified by the effect of the HER2/IGFIR inhibitor combination in HER2 nonoverexpressing MCF7 cells. [Cancer Res 2008;68(5):1538–45]
Met Receptor Contributes to Trastuzumab Resistance of Her2-Overexpressing Breast Cancer Cells
Authors: Shattuck David L. , Miller Jamie K. , Carraway Kermit L. , Sweeney Colleen
Published: March 2008

Her2 is overexpressed in 20% to 30% of breast tumors and correlates with reduced disease-free and overall patient survival. Trastuzumab, a humanized monoclonal antibody directed against Her2, represents the first Her2-targeted therapy, which decreases the risk of relapse and prolongs patient survival. Resistance to trastuzumab, both inherent and treatment-acquired, represents a significant barrier to the effective treatment of Her2 (+) breast cancer. The Met receptor tyrosine kinase is aberrantly expressed in breast cancer and predicts poor patient prognosis. In this study, we find that Met is frequently expressed in Her2-overexpressing breast cancer cells, as well as Her2 (+) breast cancer. Importantly, Met contributes to trastuzumab resistance, as inhibition of Met sensitizes cells to trastuzumab-mediated growth inhibition, whereas Met activation protects cells against trastuzumab by abrogating p27 induction. Remarkably, Her2-overexpressing breast cancer cells rapidly up-regulate Met expression after trastuzumab treatment, promoting their own resistance. Our study suggests that a subset of Her2 (+) patients may benefit from combined inhibition of Her2 and Met. [Cancer Res 2008;68(5):1471–7]
H-2Kb–Restricted CTL Epitopes from Mouse Heparanase Elicit an Antitumor Immune Response In vivo
Authors: Tang Xu-Dong , Wan Yin , Chen Ling , Chen Ting , Yu Song-Tao , Xiong Zhen , Fang Dian-Chun , Liang Guang-Ping , Yang Shi-Ming
Published: March 2008

The identification of CTL epitopes from tumor antigens is very important for the development of peptide-based, cancer-specific immunotherapy. Heparanase is broadly expressed in various advanced tumors and can serve as a universal tumor-associated antigen. Although several epitopes of heparanase antigen are known in humans, the corresponding knowledge in mice is still rather limited. The present study was designed to predict and identify the CTL epitopes in the mouse heparanase protein. For this purpose, H-2Kb–restricted CTL epitopes were identified by using the following four-step procedure: (a) a computer-based epitope prediction from the amino acid sequence of mouse heparanase, (b) a peptide-binding assay to determine the affinity of the predicted epitopes with the H-2Kb molecule, (c) the testing of the induction of CTLs toward various carcinoma cells expressing heparanase antigens and H-2Kb, and (d) the induction of immunoprotection and immunotherapy in vivo. The results showed that, of the tested peptides, effectors induced by peptides of mouse heparanase at residue positions 398 to 405 (LSLLFKKL; mHpa398) and 519 to 526 (FSYGFFVI; mHpa519) lysed three kinds of carcinoma cells expressing both heparanase and H-2Kb (B16 melanoma cells, EL-4 lymphoma cells, and Lewis lung cancer cells). In vivo experiments indicated that mHpa398 and mHpa519 peptides offered the possibility of not only immunizing against tumors but also treating tumor-bearing hosts successfully. Our results suggest that the mHpa398 and mHpa519 peptides are novel H-2Kb–restricted CTL epitopes capable of inducing heparanase-specific CTLs in vitro and in vivo. These epitopes may serve as valuable tools for the preclinical evaluation of vaccination strategies. [Cancer Res 2008;68(5):1529–37]
Use of Preoperative Plasma Endoglin for Prediction of Lymph Node Metastasis in Patients with Clinically Localized Prostate Cancer
Authors: Karam Jose A. , Svatek Robert S. , Karakiewicz Pierre I. , Gallina Andrea , Roehrborn Claus G. , Slawin Kevin M. , Shariat Shahrokh F.
Published: March 2008

Purpose: Current predictive tools and imaging modalities are not accurate enough to preoperatively diagnose lymph node metastases in patients with prostate cancer. The aim of the study was to evaluate whether preoperative plasma endoglin improves the prediction of lymph node metastases in patients with clinically localized prostate cancer.

Experimental Design: Endoglin levels were measured using a commercially available ELISA assay in banked plasma from 425 patients treated with radical prostatectomy and bilateral lymphadenectomy for clinically localized prostatic adenocarcinoma at two university hospitals between July 1994 and November 1997. Logistic regression analyses were undertaken to evaluate whether endoglin improves the accuracy of a standard preoperative model for prediction of lymph node metastasis and to build a predictive nomogram.

Results: Preoperative plasma endoglin levels were higher in patients with higher preoperative total serum prostate-specific antigen (PSA; Spearman correlation coefficient 0.296, P < 0.001), positive surgical margins (P = 0.03), higher pathologic Gleason sum (P = 0.04), and lymph node metastasis (P < 0.001). In a preoperative multivariable logistic regression analysis that included PSA and clinical stage, only preoperative endoglin (odds ratio, 1.17; 95% confidence interval, 1.09-1.26; P < 0.001) and biopsy Gleason sum (odds ratio, 18.57; 95% confidence interval, 1.08-318.36; P = 0.04) were associated with metastasis to lymph nodes. The addition of endoglin to a standard preoperative model (including PSA, clinical stage, and biopsy Gleason sum) significantly improved its accuracy for prediction of lymph node metastasis from 89.4% to 97.8% (P < 0.001).

Conclusions: Preoperative plasma endoglin improves the accuracy for prediction of pelvic lymph node metastasis in patients treated with radical prostatectomy for clinically localized prostate cancer by a statistically and clinically significant margin.
Combining the Antigen Processing Components TAP and Tapasin Elicits Enhanced Tumor-Free Survival
Authors: Lou Yuanmei , Basha Genc , Seipp Robyn P. , Cai Bing , Chen Susan S. , Moise Alexander R. , Jeffries Andrew P. , Gopaul Ray S. , Vitalis Timothy Z. , Jefferies Wilfred A.
Published: March 2008

Purpose: Tpn is a member of the MHC class I loading complex and functions to bridge the TAP peptide transporter to MHC class I molecules. Metastatic human carcinomas often express low levels of the antigen-processing components Tapasin and TAP and display few functional surface MHC class I molecules. As a result, carcinomas are unrecognizable by effector CTLs. The aim of this study is to examine if Tapasin (Tpn) plays a critical role in the escape of tumors from immunologic recognition.

Experimental Design: To test our hypothesis, a nonreplicating adenovirus vector encoding human Tpn (AdhTpn) was constructed to restore Tpn expression in vitro and in vivo in a murine lung carcinoma cell line (CMT.64) that is characterized by down-regulation of surface MHC class I due to deficiency in antigen-processing components.

Results: Ex vivo, Tpn expression increased surface MHC class I and restored susceptibility of tumor cells to antigen-specific CTL killing, and AdhTpn infection of dendritic cells also significantly increased cross-presentation and cross-priming. Furthermore, tumor-bearing animals inoculated with AdhTpn demonstrated a significant increase in CD8+ and CD4+ T cells and CD11c+ dendritic cells infiltrating the tumors. Provocatively, whereas syngeneic mice bearing tumors that were inoculated with AdhTpn a significant reduction in tumor growth and increased survival compared with vector controls, combining AdhTpn inoculation with AdhTAP1 resulted in a significant augmentation of protection from tumor-induced death than either component alone.

Conclusions: This is the first demonstration that Tpn alone can enhance survival and immunity against tumors but additionally suggests that Tpn and TAP should be used together as components of immunotherapeutic vaccine protocols to eradicate tumors.
Cell Adhesion Molecules, Vascular Endothelial Growth Factor, and Basic Fibroblast Growth Factor in Patients with Non–Small Cell Lung Cancer Treated with Chemotherapy with or without Bevacizumab—an Eastern Cooperative Oncology Group Study
Authors: Dowlati Afshin , Gray Robert , Sandler Alan B. , Schiller Joan H. , Johnson David H.
Published: March 2008

Background: E4599 was a phase II/phase III trial, in which 878 patients with advanced non–small cell lung cancer were randomized to carboplatin + paclitaxel (PC arm) or PC + bevacizumab (BPC arm). Survival and progression-free survival were superior on the BPC arm. The rationale for markers used in this correlative study was based on elevated vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), soluble intercellular adhesion molecule (ICAM) and E-selectin in a variety of malignances and changes in response to endothelial cell apoptosis.

Materials and Methods: Prospective correlates included measurements of pretreatment plasma VEGF, as well as pretreatment and week 7, bFGF, ICAM, and E-selectin. Low and high levels were defined as less than or equal to or more than the median.

Results: E-selectin (P < 0.0001) showed a decrease and bFGF showed an increase (P = 0.004) from baseline at week 7, which were similar in both arms. Baseline ICAM showed significant associations with response and survival in both groups. Patients with low baseline ICAM had a higher response rate (32% versus 14%; P = 0.02), better overall survival (P = 0.00005), and better 1-year survival (65% versus 25%) than those with high ICAM, respectively, regardless of treatment arm. Patients with high VEGF levels were more likely to respond to BPC compared with PC, but this was not predictive of survival. The results also suggest a benefit from bevacizumab for patients with low baseline ICAM levels (53% reduction in the progression-free survival hazard rate).

Conclusions: In this study, baseline ICAM levels were prognostic for survival and predictive of response to chemotherapy with or without bevacizumab. VEGF levels were predictive of response to bevacizumab but not survival.
Acquirement of Rituximab Resistance in Lymphoma Cell Lines Is Associated with Both GlobalCD20Gene and Protein Down-Regulation Regulated at the Pretranscriptional and Posttranscriptional Levels
Authors: Czuczman Myron S. , Olejniczak Scott , Gowda Aruna , Kotowski Adam , Binder Arvinder , Kaur Harman , Knight Joy , Starostik Petr , Deans Julie , Hernandez-Ilizaliturri Francisco J.
Published: March 2008

Acquirement of resistance to rituximab has been observed in lymphoma patients. To define mechanisms associated with rituximab resistance, we developed various rituximab-resistant cell lines (RRCL) and studied changes in CD20 expression/structure, lipid raft domain (LRD) reorganization, calcium mobilization, antibody-dependent cellular cytotoxicity, and complement-mediated cytotoxicity (CMC) between parental and RRCL. Significant changes in surface CD20 antigen expression were shown in RRCL. Decreased calcium mobilization and redistribution of CD20 into LRD were found in RRCL. Western blotting identified a unique 35 kDa protein band in RRCL, which was not seen in parental cells and was secondary to an increase in surface and cytoplasmic expression of IgM light chains. CD20 gene expression was decreased in RRCL. In vitro exposure to PS341 increased CD20 expression in RRCL and minimally improved the sensitivity to rituximab-associated CMC. Our data strongly suggest that the acquisition of rituximab resistance is associated with global gene and protein down-regulation of the CD20 antigen affecting LRD organization and downstream signaling. CD20 expression seems to be regulated at the pretranscriptional and posttranscriptional levels. Proteasome inhibition partially reversed rituximab resistance, suggesting the existence of additional mediators of rituximab resistance. Future research is geared to identify drugs and/or biological agents that are effective against RRCL.
Acquired Resistance to Rituximab Is Associated with Chemotherapy Resistance Resulting from Decreased Bax and Bak Expression
Authors: Olejniczak Scott H. , Hernandez-Ilizaliturri Francisco J. , Clements James L. , Czuczman Myron S.
Published: March 2008

Purpose: Targeting malignant B cells using rituximab (anti-CD20) has improved the efficacy of chemotherapy regimens used to treat patients with non-Hodgkin's lymphoma. Despite the promising clinical results obtained using rituximab, many patients relapse with therapy-resistant disease following rituximab-based treatments. We have created a cell line model of rituximab resistance using three B-cell non-Hodgkin's lymphoma–derived cell lines (Raji, RL, and SUDHL-4). In an attempt to define strategies to overcome rituximab resistance, we sought to determine the chemotherapy sensitivity of our rituximab-resistant cell lines (RRCL).

Experimental Design: Parental, rituximab-sensitive cell lines (RSCL) Raji, RL, and SUDHL-4, along with RRCLs derived from them, were exposed to several chemotherapeutic agents with different mechanisms of action and the ability of these agents to induce apoptotic cell death was measured. Expression of multidomain Bcl-2 family proteins was studied as potential mediators of chemotherapy/rituximab resistance.

Results: We found that RRCLs are resistant to multiple chemotherapeutic agents and have significantly decreased expression of the Bcl-2 family proteins Bax, Bak, and Bcl-2. RRCLs do not undergo rituximab- or chemotherapy-induced apoptosis but die in a caspase-dependent manner when either wild-type Bax or Bak is exogenously expressed. Furthermore, forced expression of Bak sensitized RRCL to chemotherapy-induced apoptosis.

Conclusions: Whereas a single or limited exposure of lymphoma cells to rituximab may lead to a favorable ratio of proapoptotic to antiapoptotic Bcl-2 family proteins, repeated exposure to rituximab is associated with a therapy-resistant phenotype via modulation of Bax and Bak expression.
HMGA1 Is a Molecular Determinant of Chemoresistance to Gemcitabine in Pancreatic Adenocarcinoma
Authors: Liau Siong-Seng , Whang Edward
Published: March 2008

Purpose: HMGA1 proteins are architectural transcription factors that are overexpressed by pancreatic adenocarcinomas. We previously have shown that RNA interference targeting the HMGA1 gene may represent a potential chemosensitizing strategy in pancreatic adenocarcinoma cells. In this study, we tested the hypothesis that HMGA1 promotes chemoresistance to gemcitabine in pancreatic cancer cells.

Experimental Design and Results: Stable short hairpin RNA–mediated HMGA1 silencing in BxPC3 and MiaPaCa2 cells promoted chemosensitivity to gemcitabine, with reductions in gemcitabine IC50 and increases in gemcitabine-induced apoptosis and caspase-3 activation. In contrast, forced HMGA1 overexpression in MiaPaCa2 cells promoted chemoresistance to gemcitabine, with increases in gemcitabine IC50 and reductions in gemcitabine-induced apoptosis and caspase-3 activation. Dominant negative Akt abrogated HMGA1 overexpression–induced increases in chemoresistance to gemcitabine. Finally, HMGA1 silencing promoted chemosensitivity to gemcitabine in vivo in a nude mouse xenograft model of pancreatic adenocarcinoma.

Conclusion: Our findings suggest that HMGA1 promotes chemoresistance to gemcitabine through an Akt-dependent mechanism. Targeted therapies directed at HMGA1 represent a potential strategy for ameliorating chemoresistance in pancreatic adenocarcinoma.
Phase I/II Study of Atrasentan, an Endothelin A Receptor Antagonist, in Combination with Paclitaxel and Carboplatin as First-Line Therapy in Advanced Non–Small Cell Lung Cancer
Authors: Chiappori Alberto A. , Haura Eric , Rodriguez Francisco A. , Boulware David , Kapoor Rachna , Neuger Anthony M. , Lush Richard , Padilla Barbara , Burton Michelle , Williams Charles , Simon George , Antonia Scott , Sullivan Daniel M. , Bepler Gerold
Published: March 2008

Purpose: Endothelins and their cell membrane receptors (ETAR and ETBR) are implicated in neoplastic pathogenesis. Atrasentan, a potent, selective ETAR antagonist, has a direct effect on tumor proliferation, apoptosis, and angiogenesis. This study was designed to assess the influence of atrasentan on paclitaxel pharmacokinetics and to determine the safety and efficacy of atrasentan in combination with paclitaxel-carboplatin.

Experimental Design: Chemonaive patients with stage IIIB (malignant pleural effusion) and IV non–small cell lung cancer were enrolled. Toxicity and response were determined using the National Cancer Institute Common Toxicity Criteria version 2.0 and Response Evaluation Criteria in Solid Tumors criteria, respectively. Treatment consisted of paclitaxel (225 mg/m2) and carboplatin (area under the curve, 6) administered on day 1 every 3 weeks. A fixed 10 mg daily oral dose of atrasentan was administered continuously, starting on day 4 of cycle 1. Paclitaxel clearance was calculated during the first two cycles (pre- and post-atrasentan) in the first 10 patients.

Results: All 44 patients were evaluable for survival, toxicity, and response. No significant change in mean paclitaxel clearance was detected (mean ± SD, 21.2 ± 4.5 L/h versus 21.3 ± 4.9 L/h) for pre- and post-atrasentan values, respectively (P = 0.434). Grade 3/4 toxicities ≥10% were lymphopenia (22.7%), neutropenia (20.5%), dyspnea (11.4%), and hyperglycemia (11.4%). Response rate was 18.2%, with progression-free survival of 4.2 months, median survival of 10.6 months, and 1-year survival of 43%.

Conclusion: Atrasentan plus paclitaxel-carboplatin was safe and well tolerated, with no apparent paclitaxel-atrasentan pharmacokinetic interaction. Efficacy and survival in advanced non–small cell lung cancer were comparable with studies of chemotherapy alone.
Sensitive and Specific New Enzyme-Linked Immunosorbent Assay for N-ERC/Mesothelin Increases its Potential as a Useful Serum Tumor Marker for Mesothelioma
Authors: Shiomi Kazu , Hagiwara Yoshiaki , Sonoue Kouji , Segawa Tatsuya , Miyashita Kazuya , Maeda Masahiro , Izumi Hiroshi , Masuda Kimihiko , Hirabayashi Masataka , Moroboshi Takao , Yoshiyama Takashi , Ishida Atsuko , Natori Yuji , Inoue Akira , Kobayashi Masashi , Sakao Yukinori , Miyamoto Hideaki , Takahashi Kazuhisa , Hino Okio
Published: March 2008

Background: Because mesothelioma initially progresses on the surface of the pleura and peritoneum without forming masses, it has been difficult to diagnose at an early stage. It would be very useful to identify a tumor marker that could be used for screening to enable more diagnoses to be made at an early, treatable stage.

Materials and Methods: We had previously identified N-ERC/mesothelin as a potential biomarker for mesothelioma. In the current work, we used a newly developed ELISA system to gain data on N-ERC/mesothelin levels in various clinical settings. A total of 102 healthy volunteers were recruited. In addition, 39 patients were diagnosed with mesothelioma, 53 patients were diagnosed with diseases that should be distinguished from mesothelioma, and 201 subjects were diagnosed with asbestos-related nonmalignant diseases (including simple exposure to asbestosis) who were treated at any of the cooperating hospitals were enrolled.

Results: Serum N-ERC/mesothelin levels measured by a new ELISA system showed that the median values from patients with mesothelioma were extremely high compared with levels obtained from other patients. Analysis in terms of histologic type showed that serum levels of N-ERC/mesothelin were elevated in epithelioid type mesothelioma, especially. In four important models of clinical settings, the sensitivity and specificity of N-ERC/mesothelin were about 71% to 90% and 88% to 93%, respectively.

Conclusion: N-ERC/mesothelin is a very promising tumor marker for mesothelioma, especially epithelioid mesothelioma.
Oncolytic Herpes Simplex Virus Type-1 Therapy in a Highly Infiltrative Animal Model of Human Glioblastoma
Authors: Huszthy Peter C. , Goplen Dorota , Thorsen Frits , Immervoll Heike , Wang Jian , Gutermann Anja , Miletic Hrvoje , Bjerkvig Rolf
Published: March 2008

We have examined the spread and antitumor efficacy of an oncolytic herpes simplex virus-1–based vector (G207) in glioblastoma biopsy spheroids in vitro and in vivo after local delivery to corresponding intracranial xenografts. Spheroids from three patients were infected with increasing doses of G207 and transgene expression was quantified. Other infected spheroids were followed for 10 days to assess cytotoxic effects. For the in vivo study, spheroids were grafted intracerebrally into Rowett nude rats. The resulting highly infiltrative xenografts were injected with 3.4 × 106 plaque-forming units (penetration study) or 6.8 × 106 plaque-forming units (therapeutic study) of G207 using microprocessor-controlled stereotaxic delivery. Vector spread was tracked by histochemical staining. In the therapeutic study, tumor volumes were monitored weekly by magnetic resonance imaging, and survival data were collected. In vitro, lacZ expression was seen at the spheroid surfaces 24 h postinfection, whereas the spheroid cores were transgene positive after 96 h. Cytotoxic susceptibility varied between the patients, showing a 36% to 95% lysis 10 days postinfection. Local delivery of G207 into intracranial xenografts resulted in extensive vector spread throughout the lesions. In the therapeutic study, G207 application reduced tumor volumes compared with controls, but did not significantly improve survival of the animals. Histologic analysis revealed infection of host structures such as the ventricular and choroid plexus ependyma. In conclusion, G207 replicates in patient-derived glioblastoma multiforme xenografts and tumor volumes are reduced after intratumoral delivery; however, the survival data suggest that the therapeutic effect could be improved by repeated vector application or through combination with other treatment modalities.
Platinum Resistance: The Role of DNA Repair Pathways
Authors: Martin Lainie P. , Hamilton Thomas C. , Schilder Russell J.
Published: March 2008

Although platinum chemotherapeutic agents such as carboplatin, cisplatin, and oxaliplatin are used to treat a broad range of malignant diseases, their efficacy in most cancers is limited by the development of resistance. There are multiple factors that contribute to platinum resistance but alterations of DNA repair processes have been known for some time to be important in mediating resistance. Recently acquired knowledge has provided insight into the molecular mechanisms of DNA repair pathways and their effect on response to chemotherapy. This review will discuss the most important DNA repair pathways known to be involved in the platinum response, i.e., nucleotide excision repair (NER) and mismatch repair (MMR), and will briefly touch on the role of BRCA in DNA repair. The therapeutic implications of alterations in DNA repair which affect response to platinum in the treatment of patients with malignant disease, such as excision repair cross-complementation group 1 (ERCC1) deficiency and mismatch repair deficiency, will be reviewed.
Dietary Intake of Lactose as a Strong Predictor for Secretor Status of Nipple Aspirate Fluid in Healthy Premenopausal Nonlactating Women
Authors: Huang Yafei , Anderson Karl E. , Nagamani Manubai , Grady James J. , Lu Lee-Jane W.
Published: March 2008

Purpose: Nipple aspirate fluid (NAF) is considered a potential source for discovering breast cancer biomarkers. However, the success rate of obtaining NAF was reported to vary from 48% to 77%, and mechanisms for its secretion are not fully understood. The purpose of this study was to investigate dietary, demographic, reproductive, hormonal, and anthropometric factors that are associated with the ability to obtain NAF by aspiration (secretor status) from premenopausal women.

Study Design: NAF procedures were attempted for women who were 30 to 40 years old, not pregnant, not breast-feeding, and not taking contraceptive medications.

Results: Compared with nonsecretors, secretors of NAF consumed significantly more dietary lactose (mainly from milk), were more likely to be parous, were older at first and last childbirth, breast-fed their babies for a longer period of time, and had an earlier menarche and lower plasma concentrations of 17β-estradiol (P < 0.05). Using multivariate logistic regression models, higher dietary intake of lactose [odds ratio (OR), 2.7; 95% confidence interval (95% CI), 1.5-4.8], earlier menarche (OR, 0.8; 95% CI, 0.7-1.0), being parous (OR, 2.3; 95% CI, 1.0-5.6), and being older at first childbirth (OR, 1.5; 95% CI, 1.0-2.1) were found to be independent and positive predictors for being a secretor of NAF.

Conclusions: These findings suggest that dietary intake of lactose, a modifiable factor, may be used to change the NAF secretor status of women. This finding may facilitate the use of NAF as a diagnostic material for detecting breast diseases.