Supraphysiological Androgens Promote the Tumor Suppressive Activity of the Androgen Receptor through cMYC Repression and Recruitment of the DREAM Complex

The androgen receptor (AR) pathway regulates key cell survival programs in prostate epithelium. The AR represents a near-universal driver and therapeutic vulnerability in metastatic prostate cancer, and targeting AR has a remarkable therapeutic index. Though most approaches directed toward AR focus on inhibiting AR signaling, laboratory and now clinical data have shown that high dose, supraphysiological androgen treatment (SPA) results in growth repression and improved outcomes in subsets of patients with prostate cancer. A better understanding of the mechanisms contributing to SPA response and resistance could help guide patient selection and combination therapies to improve efficacy. To characterize SPA signaling, we integrated metrics of gene expression changes induced by SPA together with cistrome data and protein-interactomes. These analyses indicated that the dimerization partner, RB-like, E2F, and multivulval class B (DREAM) complex mediates growth repression and downregulation of E2F targets in response to SPA. Notably, prostate cancers with complete genomic loss of RB1 responded to SPA treatment, whereas loss of DREAM complex components such as RBL1/2 promoted resistance. Overexpression of MYC resulted in complete resistance to SPA and attenuated the SPA/AR-mediated repression of E2F target genes. These findings support a model of SPA-mediated growth repression that relies on the negative regulation of MYC by AR leading to repression of E2F1 signaling via the DREAM complex. The integrity of MYC signaling and DREAM complex assembly may consequently serve as determinants of SPA responses and as pathways mediating SPA resistance.

SIGNIFICANCE

Determining the molecular pathways by which supraphysiological androgens promote growth arrest and treatment responses in prostate cancer provides opportunities for biomarker-selected clinical trials and the development of strategies to augment responses.

Nucleosome Patterns in Circulating Tumor DNA Reveal Transcriptional Regulation of Advanced Prostate Cancer Phenotypes

Advanced prostate cancers comprise distinct phenotypes, but tumor classification remains clinically challenging. Here, we harnessed circulating tumor DNA (ctDNA) to study tumor phenotypes by ascertaining nucleosome positioning patterns associated with transcription regulation. We sequenced plasma ctDNA whole genomes from patient-derived xenografts representing a spectrum of androgen receptor active (ARPC) and neuroendocrine (NEPC) prostate cancers. Nucleosome patterns associated with transcriptional activity were reflected in ctDNA at regions of genes, promoters, histone modifications, transcription factor binding, and accessible chromatin. We identified the activity of key phenotype-defining transcriptional regulators from ctDNA, including AR, ASCL1, HOXB13, HNF4G, and GATA2. To distinguish NEPC and ARPC in patient plasma samples, we developed prediction models that achieved accuracies of 97% for dominant phenotypes and 87% for mixed clinical phenotypes. Although phenotype classification is typically assessed by IHC or transcriptome profiling from tumor biopsies, we demonstrate that ctDNA provides comparable results with diagnostic advantages for precision oncology.

SIGNIFICANCE

This study provides insights into the dynamics of nucleosome positioning and gene regulation associated with cancer phenotypes that can be ascertained from ctDNA. New methods for classification in phenotype mixtures extend the utility of ctDNA beyond assessments of somatic DNA alterations with important implications for molecular classification and precision oncology. This article is highlighted in the In This Issue feature, p. 517.

Comprehensive assessment of anaplastic lymphoma kinase in localized and metastatic prostate cancer reveals targetable alterations

Anaplastic lymphoma kinase (ALK) is a tyrosine kinase with genomic and expression changes in many solid tumors. ALK inhibition is first line therapy for lung cancers with ALK alterations, and an effective therapy in other tumor types, but has not been well-studied in prostate cancer. Here, we aim to delineate the role of ALK genomic and expression changes in primary and metastatic prostate cancer. We determined ALK expression by immunohistochemistry and RNA-Seq, and genomic alterations by NGS. We assessed functional consequences of ALK overexpression and pharmacological ALK inhibition by cell proliferation and cell viability assays. Among 372 primary prostate cancer cases we identified one case with uniformly high ALK protein expression. Genomic analysis revealed a SLC45A3-ALK fusion which promoted oncogenesis in in vitro assays. We observed ALK protein expression in 5/52 (9%) of metastatic prostate cancer cases, of which 4 of 5 had neuroendocrine features. ALK-expressing neuroendocrine prostate cancer had a distinct transcriptional program, and earlier disease progression. An ALK-expressing neuroendocrine prostate cancer model was sensitive to pharmacological ALK inhibition. In summary, we found that ALK overexpression is rare in primary prostate cancer, but more frequent in metastatic prostate cancers with neuroendocrine differentiation. Further, ALK fusions similar to lung cancer are an occasional driver in prostate cancer. Our data suggest that ALK-directed therapies could be an option in selected patients with advanced prostate cancer.

Genomic attributes of homology-directed DNA repair deficiency in metastatic prostate cancer

Cancers with homology-directed DNA repair (HRR) deficiency exhibit high response rates to poly(ADP-ribose) polymerase inhibitors (PARPi) and platinum chemotherapy. Though mutations disrupting BRCA1 and BRCA2 associate with HRR deficiency (HRRd), patterns of genomic aberrations and mutation signatures may be more sensitive and specific indicators of compromised repair. Here, we evaluated whole-exome sequences from 418 metastatic prostate cancers (mPCs) and determined that one-fifth exhibited genomic characteristics of HRRd that included Catalogue Of Somatic Mutations In Cancer mutation signature 3. Notably, a substantial fraction of tumors with genomic features of HRRd lacked biallelic loss of a core HRR-associated gene, such as BRCA2. In this subset, HRRd associated with loss of chromodomain helicase DNA binding protein 1 but not with mutations in serine-protein kinase ATM, cyclin dependent kinase 12, or checkpoint kinase 2. HRRd genomic status was strongly correlated with responses to PARPi and platinum chemotherapy, a finding that supports evaluating biomarkers reflecting functional HRRd for treatment allocation.

BET Bromodomain Inhibition Blocks an AR-Repressed, E2F1-Activated Treatment-Emergent Neuroendocrine Prostate Cancer Lineage Plasticity Program

PURPOSE

Lineage plasticity in prostate cancer-most commonly exemplified by loss of androgen receptor (AR) signaling and a switch from a luminal to alternate differentiation program-is now recognized as a treatment resistance mechanism. Lineage plasticity is a spectrum, but neuroendocrine prostate cancer (NEPC) is the most virulent example. Currently, there are limited treatments for NEPC. Moreover, the incidence of treatment-emergent NEPC (t-NEPC) is increasing in the era of novel AR inhibitors. In contradistinction to de novo NEPC, t-NEPC tumors often express the AR, but AR's functional role in t-NEPC is unknown. Furthermore, targetable factors that promote t-NEPC lineage plasticity are also unclear.

EXPERIMENTAL DESIGN

Using an integrative systems biology approach, we investigated enzalutamide-resistant t-NEPC cell lines and their parental, enzalutamide-sensitive adenocarcinoma cell lines. The AR is still expressed in these t-NEPC cells, enabling us to determine the role of the AR and other key factors in regulating t-NEPC lineage plasticity.

RESULTS

AR inhibition accentuates lineage plasticity in t-NEPC cells-an effect not observed in parental, enzalutamide-sensitive adenocarcinoma cells. Induction of an AR-repressed, lineage plasticity program is dependent on activation of the transcription factor E2F1 in concert with the BET bromodomain chromatin reader BRD4. BET inhibition (BETi) blocks this E2F1/BRD4-regulated program and decreases growth of t-NEPC tumor models and a subset of t-NEPC patient tumors with high activity of this program in a BETi clinical trial.

CONCLUSIONS

E2F1 and BRD4 are critical for activating an AR-repressed, t-NEPC lineage plasticity program. BETi is a promising approach to block this program.

Identification of Therapeutic Vulnerabilities in Small-cell Neuroendocrine Prostate Cancer

PURPOSE

Small-cell neuroendocrine prostate cancer (SCNPC) exhibits an aggressive clinical course and incidence rates seem to be increasing following resistance to potent androgen receptor (AR) antagonists. Currently, treatment options are limited and few model systems are available to identify new approaches for treatment. We sought to evaluate commonalities between SCNPC and other aggressive neuroendocrine carcinomas to identify therapeutic targets.

EXPERIMENTAL DESIGN

We generated whole transcriptome RNA-sequencing data from AR-active prostate cancers (ARPCs) and SCNPCs from tumors collected at rapid autopsy and two other neuroendocrine carcinomas, Merkel cell carcinoma (MCC), and small-cell lung cancer. We performed cross-tumor comparisons to identify conserved patterns of expression of druggable targets. We tested inhibitors to highly upregulated drug targets in a panel of prostate cancer cell lines and in vivo patient-derived xenograft (PDX) models.

RESULTS

We identified BCL2 as highly upregulated in SCNPC compared with ARPC. Inhibitors targeting BCL2 induced apoptotic cell death in SCNPC cell lines at nanomolar concentrations while ARPC cell lines were resistant. Treatment with the BCL2 inhibitor navitoclax leads to a reduction of growth of SCNPC PDX tumors in vivo, whereas ARPC PDX models were more resistant. We identified Wee1 as a second druggable target upregulated in SCNPC. Treatment with the combination of navitoclax and the Wee1 inhibitor AZD-1775 repressed the growth of SCNPC PDX resistant to single-agent BCL2 inhibitors.

CONCLUSIONS

The combination of BCL2 and Wee1 inhibition presents a novel therapeutic strategy for the treatment of SCNPC.

Molecular determinants of response to high-dose androgen therapy in prostate cancer

Clinical trials of high-dose androgen (HDA) therapy for prostate cancer (PC) have shown promising efficacy but are limited by lack of criteria to identify likely responders. To elucidate factors that govern the growth-repressive effects of HDAs, we applied an unbiased integrative approach using genetic screens and transcriptional profiling of PC cells with or without demonstrated phenotypic sensitivity to androgen-mediated growth repression. Through this comprehensive analysis, we identified genetic events and related signaling networks that determine the response to both HDA and androgen withdrawal. We applied these findings to develop a gene signature that may serve as an early indicator of treatment response and identify men with tumors that are amenable to HDA therapy.

Supraphysiological androgens suppress prostate cancer growth through androgen receptor-mediated DNA damage

Prostate cancer (PC) is initially dependent on androgen receptor (AR) signaling for survival and growth. Therapeutics designed to suppress AR activity serve as the primary intervention for advanced disease. However, supraphysiological androgen (SPA) concentrations can produce paradoxical responses leading to PC growth inhibition. We sought to discern the mechanisms by which SPA inhibits PC and to determine if molecular context associates with anti-tumor activity. SPA produced an AR-mediated, dose-dependent induction of DNA double-strand breaks (DSBs), G0/G1 cell cycle arrest and cellular senescence. SPA repressed genes involved in DNA repair and delayed the restoration of damaged DNA which was augmented by PARP1 inhibition. SPA-induced DSBs were accentuated in BRCA2-deficient PCs, and combining SPA with PARP or DNA-PKcs inhibition further repressed growth. Next-generation sequencing was performed on biospecimens from PC patients receiving SPA as part of ongoing Phase II clinical trials. Patients with mutations in genes mediating homology-directed DNA repair were more likely to exhibit clinical responses to SPA. These results provide a mechanistic rationale for directing SPA therapy to PCs with AR amplification or DNA repair deficiency, and for combining SPA therapy with PARP inhibition.

Abstract 2962: Targeting BCL2 as a therapeutic strategy in neuroendocrine prostate cancer

Small-cell neuroendocrine prostate carcinoma (SC/NEPC) is an aggressive subtype of prostate cancer (PC) with poor response to conventional therapies and no approved targeted therapies. The molecular mechanisms that drive the growth and survival of these tumors are poorly understood due to disease rarity and a lack of model systems for the subtype. SC/NEPC shares defining characteristics with other aggressive small-cell neuroendocrine tumors, such as “small-blue round cell” morphology and expression of chromogranin A. In this study, we compare whole transcriptome RNA-sequencing data from metastatic PCs and two additional SC/NE tumor types, small cell lung cancer (SCLC) and Merkel Cell carcinoma (MCC). By differential expression analysis of each neuroendocrine tumor type to Androgen Receptor-responsive Prostate Cancer (AR-PC), we identify 4,300 genes exhibiting shared expression patterns in multiple neuroendocrine tumor types. Among these “pan-neuroendocrine” genes are known and proposed drivers of the neuroendocrine transcriptional program including MYCN (p=8.7E-07, upregulated in SC/NEPC over AR-PC) and potential novel drivers of the neuroendocrine phenotype in PC such as MYCL (p=3.5E-05, upregulated in SC/NEPC over AR-PC). We also identify conserved expression patterns of druggable targets including BCL2 which has previously been reported as highly expressed in subsets of SCLC and MCC, but not SC/NEPC (p=1.24E-05, upregulated in SC/NEPC over AR-PC). We then analyzed a panel of cell lines and novel PDX models, which further confirm that the BCL2 protein is highly expressed specifically in the SC/NEPC phenotype. We determined that SC/NEPC cell lines and PDX models are sensitive to BCL2 family member inhibitors targeting BCL2, BCLXL, BCLW, including, ABT263, ABT199 and ABT737, at sub-micromolar concentrations, whereas models of ARPC were resistant. These inhibitors lead to apoptotic cell death in SC/NEPC. Collectively, our data suggests that BCL2 inhibition may present a novel targeted approach for SC/NEPC that warrants further evaluation.

Citation Format: Alexandra N. Corella, Jared M. Lucas, Arja Kaipainen, Ilsa M. Coleman, Colm Morrissey, Eva Corey, Paul Nghiem, David MacPherson, Peter S. Nelson. Targeting BCL2 as a therapeutic strategy in neuroendocrine prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2962.

Abstract B049: DNA damage echoes are key to prostate cancer susceptibility to supraphysiologic androgen levels

Purpose: Prostate cancer cells are dependent on AR for growth and survival, but recent reports have shown a paradoxical role of supraphysiologic androgen in growth inhibition, known as hormone interference. Androgen stimulation in AR-overexpressing prostate cancer cells leads to formation of double-strand breaks (DSBs). Here, we investigate the potential mechanism of high androgen induced DSBs and growth inhibition and its effect on survival following androgen stimulation in combination with DNA damage repair inhibitors or defects.

Experimental Design: AR-dependent LNCaP, AR overexpressing LNCaP and PC3, AR-independent PC3, and APIPC were used for this study. High levels of androgen (R1881)/ DHT and olaparib-induced DNA damage were evaluated by gH2AX and 53BP1 foci formation after 6 or 24h. For cell death assays the drug was administered continuously for 3 days following the plating day. DNA PKcs activity was determined by Ser2056foci formation and dissociation from chromatin was measured by Thr2609 foci. AR activity or DNA binding was evaluated by Ser81 AR phosphorylation. An ex vivo PDX model (LuCaP 96CR) was utilized to mimic the BRCA2 defect condition.

Results: We demonstrated that supraphysiologic androgen treatment on androgen-dependent and AR-overexpressing prostate cancer cell lines resulted in a dose-dependent induction of widespread DSBs, which was augmented after PARP inhibition (olaparib). AR expression correlated with persistent DNA damage as AR-independent cells lacked DSBs. High androgen treatment significantly induced caspase activity and reduced survival in AR-overexpressing cells. Hyperactivated DNA PKcs was retained on chromatin following high androgen exposure in these cells, leading to impaired dissociation of DNA PKcs from chromatin and inducing DNA damage. AR phosphorylation at Ser81 was also in concordance with hyperphosphorylated DNA PKcs, particularly in AR-overexpressing cells following high androgen and olaparib treatment. HR-deficient, BRCA2-null cells induced more DSBs after high androgen treatment with or without olaparib and were susceptible to DNA PKcs inhibition following androgen treatment. In contrast to this, AR-overexpressing cells did not exhibit any DNA damage following DNA PKcs inhibition after high androgen exposure. Ex vivo PDX models demonstrated a synergistic interaction between olaparib and high levels of androgen-induced DSB formation as well as hyperactive DNA PKcs.

Conclusions: These results suggest a potential mechanism of supraphysiologic androgen stimulated AR-induced DNA damage and proliferation inhibition. AR binds to DNA PKcs following high androgen and until AR levels become saturated DNA PKcs and AR stay on the chromatin, which leads to inefficient DNA damage repair. HR-deficient cells were particularly susceptible to high androgen. Our data provide a mechanistic rationale for the response of AR upregulated cells as well as DNA repair deficient cells to supraphysiologic androgen therapy in combination with PARP inhibition.

Citation Format: Payel Chatterjee, Jared M. Lucas, Michael D. Nyquist, Eva Corey, Peter S. Nelson. DNA damage echoes are key to prostate cancer susceptibility to supraphysiologic androgen levels [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr B049.

Abstract IA21: AR is ablated: Now what? Targeting the double-negative phenotype

Background/Introduction: Androgen receptor (AR) signaling is a distinctive feature of prostate cancer (PC) and represents the major therapeutic target for treating metastatic prostate cancer (mPC). Though highly effective, AR antagonism can produce tumors that bypass a functional requirement for AR, often through neuroendocrine (NE) transdifferentiation. Through the molecular assessment of mPCs over two decades, we find that a phenotypic shift has occurred in mPC with the emergence of an AR-null NE-null phenotype. We sought to identify drivers of these “double-negative” PCs (DNPC), with the ultimate objective of developing therapeutic strategies.

Methods: We used genome-wide profiling of copy number (array CGH), mutations (whole-exome sequencing-WES), and gene expression (RNA-seq) to compare the molecular landscapes of AR-active PC (ARPC), NEPC, and DNPC in tumors obtained from 84 consecutive men with mPC undergoing a rapid autopsy. We developed model systems including DNPC patient-derived xenografts (PDX) and cell lines that are devoid of AR activity and lack NE features. Using these models, we tested therapeutics hypothesized to inhibit the activity of pathways preferentially active in DNPC.

Results: In the era prior to the approval of the AR pathway antagonists enzalutamide and abiraterone, most CRPCs were ARPCs (85%) with rare NEPCs (10%) and rarer DNPCs (5%). In the contemporary era (2012-2016), we observed a shift in tumor phenotypes with a higher representation of DNPCs. Gene expression programs of the tumors classified by IHC supported these distinct subtypes. DNPCs did not exhibit GR activity or PI3K/AKT activation but were notable for high MAPK and FGF pathway activity. Models systems recapitulated these findings. FGFR antagonists differentially repressed the growth of DNPC tumors in vitro and in vivo.

Conclusions: Though the majority of mPCs that resist AR targeting retain AR signaling, an increasingly common subtype of mPC exhibits a DNPC phenotype. Our results indicate that at least a subset of these DNPCs are driven by FGF signaling and MAPK activation. Targeting the FGF axis may represent a therapeutic approach for those cancers resistant to AR-directed therapies and may circumvent treatment resistance if combined with initial AR pathway blockade.

Citation Format: Colm Morrissey, Eric G. Bluemn, Ilsa M. Coleman, Jared M. Lucas, Roger T. Coleman, Robin Tharakan, Daniella Bianchi-Frias, Ruth F. Dumpit, Arja Kaipainen, Alexandra N. Corella, Yu Chi Yang, Michael D. Nyquist, Elahe Mostaghel, Xiaotun Zhang, Eva Corey, Lisha G. Brown, Holly M. Nguyen, Michael Schweizer, Lawrence D. True, Paul S. Rennie, Robert L. Vessella, Peter S. Nelson. AR is ablated: Now what? Targeting the double-negative phenotype [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr IA21.

Androgen Receptor Pathway-Independent Prostate Cancer Is Sustained through FGF Signaling

Androgen receptor (AR) signaling is a distinctive feature of prostate carcinoma (PC) and represents the major therapeutic target for treating metastatic prostate cancer (mPC). Though highly effective, AR antagonism can produce tumors that bypass a functional requirement for AR, often through neuroendocrine (NE) transdifferentiation. Through the molecular assessment of mPCs over two decades, we find a phenotypic shift has occurred in mPC with the emergence of an AR-null NE-null phenotype. These "double-negative" PCs are notable for elevated FGF and MAPK pathway activity, which can bypass AR dependence. Pharmacological inhibitors of MAPK or FGFR repressed the growth of double-negative PCs in vitro and in vivo. Our results indicate that FGF/MAPK blockade may be particularly efficacious against mPCs with an AR-null phenotype.

A proteolytic modification of AIM promotes its renal excretion

Apoptosis inhibitor of macrophage (AIM, encoded by cd5l) is a multi-functional circulating protein that has a beneficial role in the regulation of a broad range of diseases, some of which are ameliorated by AIM administration in mice. In blood, AIM is stabilized by association with IgM pentamers and maintains its high circulating levels. The mechanism regulating the excessive accumulation of blood AIM remains unknown, although it is important, since a constitutive increase in AIM levels promotes chronic inflammation. Here we found a physiological AIM-cleavage process that induces destabilization of AIM and its excretion in urine. In blood, IgM-free AIM appeared to be cleaved and reduced in size approximately 10 kDa. Cleaved AIM was unable to bind to IgM and was selectively filtered by the glomerulus, thereby excreted in urine. Amino acid substitution at the cleavage site resulted in no renal excretion of AIM. Interestingly, cleaved AIM retained a comparable potency with full-length AIM in facilitating the clearance of dead cell debris in injured kidney, which is a key response in the recovery of acute kidney injury. Identification of AIM-cleavage and resulting functional modification could be the basis for designing safe and efficient AIM therapy for various diseases.

Evidence in immunotherapy for paediatric respiratory allergy: Advances and recommendations

Allergic respiratory diseases are major health problems in paediatric population due their high level of prevalence and chronicity, and to their relevance in the costs and quality of life. One of the most important risk factors for the development of airway diseases in children and adolescents is atopy. The mainstays for the treatment of these diseases are avoiding allergens, controlling symptoms, and preventing them through sustained desensitization by allergen immunotherapy (AIT). AIT is a treatment option that consists in the administration of increasing amounts of allergens to modify the biological response to them, inducing long-term tolerance even after treatment has ended. This treatment approach has shown to decrease symptoms and improve quality of life, becoming cost effective for a large number of patients. In addition, it is considered the only treatment that can influence the natural course of the disease by targeting the cause of the allergic inflammatory response. The aim of this publication is to reflect the advances of AIT in the diagnosis and treatment of allergic respiratory diseases in children and adolescents reviewing articles published since 2000, establishing evidence categories to support the strength of the recommendations based on evidence. The first part of the article covers the prerequisite issues to understand how AIT is effective, such as the correct etiologic and clinical diagnosis of allergic respiratory diseases. Following this, the article outlines the advancements in understanding the mechanisms by which AIT achieve immune tolerance to allergens. Administration routes, treatment regimens, dose and duration, efficacy, safety, and factors associated with adherence are also reviewed. Finally, the article reviews future advances in the research of AIT.

Substantial interindividual and limited intraindividual genomic diversity among tumors from men with metastatic prostate cancer

Tumor heterogeneity may reduce the efficacy of molecularly guided systemic therapy for cancers that have metastasized. To determine whether the genomic alterations in a single metastasis provide a reasonable assessment of the major oncogenic drivers of other dispersed metastases in an individual, we analyzed multiple tumors from men with disseminated prostate cancer through whole-exome sequencing, array comparative genomic hybridization (CGH) and RNA transcript profiling, and we compared the genomic diversity within and between individuals. In contrast to the substantial heterogeneity between men, there was limited diversity among metastases within an individual. The number of somatic mutations, the burden of genomic copy number alterations and aberrations in known oncogenic drivers were all highly concordant, as were metrics of androgen receptor (AR) activity and cell cycle activity. AR activity was inversely associated with cell proliferation, whereas the expression of Fanconi anemia (FA)-complex genes was correlated with elevated cell cycle progression, expression of the E2F transcription factor 1 (E2F1) and loss of retinoblastoma 1 (RB1). Men with somatic aberrations in FA-complex genes or in ATM serine/threonine kinase (ATM) exhibited significantly longer treatment-response durations to carboplatin than did men without defects in genes encoding DNA-repair proteins. Collectively, these data indicate that although exceptions exist, evaluating a single metastasis provides a reasonable assessment of the major oncogenic driver alterations that are present in disseminated tumors within an individual, and thus may be useful for selecting treatments on the basis of predicted molecular vulnerabilities.

Long non-coding RNA: A newly deciphered "code" in prostate cancer

As one of the most frequently diagnosed cancers in males, the development and progression of prostate cancer remains an open area of research. The role of lncRNAs in prostate cancer is an emerging field of study. In this review, we summarize what is currently known about lncRNAs in prostate cancer while focusing on a few key lncRNAs. PCA3 was the first lncRNA identified in prostate cancer and has been shown to be expressed in a majority of prostate cancer cases. It may act in both an androgen dependent and independent fashion and has clinical utility as a biomarker. Other lncRNAs are known to interact directly with the androgen receptor pathway including PlncRNA-1, HOTAIR, PRNCR1 and PCGEM1. Additionally, lncRNAs have been shown to interfere with tumor suppressors, DNA break repair, transcription and alternate RNA splicing. While only in its infancy, an understanding of the role of lncRNAs in prostate cancer development should present ample opportunities for the discovery of new cancer biomarkers and therapeutic targets.

DNA damage induces GDNF secretion in the tumor microenvironment with paracrine effects promoting prostate cancer treatment resistance

Though metastatic cancers often initially respond to genotoxic therapeutics, acquired resistance is common. In addition to cytotoxic effects on tumor cells, DNA damaging agents such as ionizing radiation and chemotherapy induce injury in benign cells of the tumor microenvironment resulting in the production of paracrine-acting factors capable of promoting tumor resistance phenotypes. In studies designed to characterize the responses of prostate and bone stromal cells to genotoxic stress, we found that transcripts encoding glial cell line-derived neurotrophic factor (GDNF) increased several fold following exposures to cytotoxic agents including radiation, the topoisomerase inhibitor mitoxantrone and the microtubule poison docetaxel. Fibroblast GDNF exerted paracrine effects toward prostate cancer cells resulting in enhanced tumor cell proliferation and invasion, and these effects were concordant with the expression of known GDNF receptors GFRA1 and RET. Exposure to GDNF also induced tumor cell resistance to mitoxantrone and docetaxel chemotherapy. Together, these findings support an important role for tumor microenvironment damage responses in modulating treatment resistance and identify the GDNF signaling pathway as a potential target for improving responses to conventional genotoxic therapeutics.

SRRM4 Expression and the Loss of REST Activity May Promote the Emergence of the Neuroendocrine Phenotype in Castration-Resistant Prostate Cancer

PURPOSE

The neuroendocrine phenotype is associated with the development of metastatic castration-resistant prostate cancer (CRPC). Our objective was to characterize the molecular features of the neuroendocrine phenotype in CRPC.

EXPERIMENTAL DESIGN

Expression of chromogranin A (CHGA), synaptophysin (SYP), androgen receptor (AR), and prostate-specific antigen (PSA) was analyzed by IHC in 155 CRPC metastases from 50 patients and in 24 LuCaP prostate cancer patient-derived xenografts (PDX). Seventy-one of 155 metastases and the 24 LuCaP xenograft lines were analyzed by whole-genome microarrays. REST splicing was verified by PCR.

RESULTS

Coexpression of CHGA and SYP in >30% of cells was observed in 22 of 155 metastases (9 patients); 11 of the 22 metastases were AR(+)/PSA(+) (6 patients), 11/22 were AR-/PSA- (4 patients), and 4/24 LuCaP PDXs were AR(-)/PSA(-). By IHC, of the 71 metastases analyzed by whole-genome microarrays, 5 metastases were CHGA(+)/SYP(+)/AR(-), and 5 were CHGA(+)/SYP(+)/AR(+). Only CHGA(+)/SYP(+) metastases had a neuroendocrine transcript signature. The neuronal transcriptional regulator SRRM4 transcript was associated with the neuroendocrine signature in CHGA(+)/SYP(+) metastases and all CHGA(+)/SYP(+) LuCaP xenografts. In addition, expression of SRRM4 in LuCaP neuroendocrine xenografts correlated with a splice variant of REST that lacks the transcriptional repressor domain.

CONCLUSIONS

(i) Metastatic neuroendocrine status can be heterogeneous in the same patient, (ii) the CRPC neuroendocrine molecular phenotype can be defined by CHGA(+)/SYP(+) dual positivity, (iii) the neuroendocrine phenotype is not necessarily associated with the loss of AR activity, and (iv) the splicing of REST by SRRM4 could promote the neuroendocrine phenotype in CRPC.

Chemotherapy-induced monoamine oxidase expression in prostate carcinoma functions as a cytoprotective resistance enzyme and associates with clinical outcomes

To identify molecular alterations in prostate cancers associating with relapse following neoadjuvant chemotherapy and radical prostatectomy patients with high-risk localized prostate cancer were enrolled into a phase I-II clinical trial of neoadjuvant chemotherapy with docetaxel and mitoxantrone followed by prostatectomy. Pre-treatment prostate tissue was acquired by needle biopsy and post-treatment tissue was acquired by prostatectomy. Prostate cancer gene expression measurements were determined in 31 patients who completed 4 cycles of neoadjuvant chemotherapy. We identified 141 genes with significant transcript level alterations following chemotherapy that associated with subsequent biochemical relapse. This group included the transcript encoding monoamine oxidase A (MAOA). In vitro, cytotoxic chemotherapy induced the expression of MAOA and elevated MAOA levels enhanced cell survival following docetaxel exposure. MAOA activity increased the levels of reactive oxygen species and increased the expression and nuclear translocation of HIF1α. The suppression of MAOA activity using the irreversible inhibitor clorgyline augmented the apoptotic responses induced by docetaxel. In summary, we determined that the expression of MAOA is induced by exposure to cytotoxic chemotherapy, increases HIF1α, and contributes to docetaxel resistance. As MAOA inhibitors have been approved for human use, regimens combining MAOA inhibitors with docetaxel may improve clinical outcomes.

The androgen-regulated protease TMPRSS2 activates a proteolytic cascade involving components of the tumor microenvironment and promotes prostate cancer metastasis

TMPRSS2 is an androgen-regulated cell-surface serine protease expressed predominantly in prostate epithelium. TMPRSS2 is expressed highly in localized high-grade prostate cancers and in the majority of human prostate cancer metastases. Through the generation of mouse models with a targeted deletion of Tmprss2, we demonstrate that the activity of this protease regulates cancer cell invasion and metastasis to distant organs. By screening combinatorial peptide libraries, we identified a spectrum of TMPRSS2 substrates that include pro-hepatocyte growth factor (HGF). HGF activated by TMPRSS2 promoted c-MET receptor tyrosine kinase signaling, and initiated a proinvasive epithelial-to-mesenchymal transition phenotype. Chemical library screens identified a potent bioavailable TMPRSS2 inhibitor that suppressed prostate cancer metastasis in vivo. Together, these findings provide a mechanistic link between androgen-regulated signaling programs and prostate cancer metastasis that operate via context-dependent interactions with extracellular constituents of the tumor microenvironment.

SIGNIFICANCE

The vast majority of prostate cancer deaths are due to metastasis. Loss of TMPRSS2 activity dramatically attenuated the metastatic phenotype through mechanisms involving the HGF-c-MET axis. Therapeutic approaches directed toward inhibiting TMPRSS2 may reduce the incidence or progression of metastasis in patients with prostate cancer.

Allergen-specific immunotherapy: update on immunological mechanisms

Immunotherapy selectively modulates the allergen-specific immune response. It involves the gradual administration of increasing amounts of allergen for the purpose of inducing protective immunological changes and it is the only curative approach for specific type I allergy.

AIM

Description of the allergic inflammation.- Comprehension of the early cellular changes after specific immunotherapy has been initiated. Exposure of the mechanisms involved in tolerance induction by regulatory T cells (Treg) with the inhibition of the Th2 responses. Comprehension of IL-10 and transforming growth factor (TGF- ) roles. Explanation of specific IgE, IgG and IgA changes. Description of the suppression of inflammatory responses during immunotherapy.

Prognostic value of ERG oncoprotein in prostate cancer recurrence and cause-specific mortality

BACKGROUND

ETS-related gene (ERG) protein is present in 40-70% of prostate cancer and is correlated with TMPRSS2-ERG gene rearrangements. This study evaluated ERG expression at radical prostatectomy to determine whether it was predictive of earlier relapse or prostate cancer-specific mortality (PCSM).

METHODS

One hundred patients who underwent radical prostatectomy at Virginia Mason in Seattle between 1991 and 1997 were identified. Recurrence was confirmed by tissue diagnosis or radiographic signs. PCSM was confirmed by death certificates. Thirty-three patients with metastases or PCSM were matched to patients without recurrence at a 1:2 ratio. Paraffin embedded tissue was stained with two anti-ERG monoclonal antibodies, EPR3864 and 9FY. Nuclear expression intensity was evaluated as present/absent, on a 4-point relative intensity scale, and as a composite score (0-300).

RESULTS

Mean follow-up was 10.26 years. The two antibodies were highly correlated (P < 0.0001). Patients with higher ERG expression intensity and composite scores were significantly more likely to develop biochemical relapse, metastases, and PCSM. Kaplan-Meier survival curve analysis for the composite score of ERG expression revealed a significant association between higher ERG expression (EPR3864) and shorter PCa-specific survival (P = 0.047).

CONCLUSIONS

While the presence of ERG expression at the time of surgery was not predictive of earlier relapse or PCSM, the relative intensity and composite score for ERG expression was prognostic for the development of biochemical relapse, metastases, and PCSM. Quantitative ERG scoring may be useful to identify patients who would benefit from adjuvant treatment or closer follow-up, allowing more accurate individual patient treatment plans.

Competitive role of CH4-CH4 and CH-π interactions in C6H6-(CH4)n aggregates: the transition from dimer to cluster features

The intermolecular methane-methane and benzene (Bz)-methane interactions formulated in this paper are suitable to investigate systems of increasing complexity. The proposed CH(4)-CH(4) and Bz-CH(4) potential energy functions are indeed applied to study some macroscopic properties of methane and important features of both small Bz-(CH(4))(n) (n > 1-10) clusters and Bz surrounded by several CH(4) molecules. Relevant parameters of the interaction, derived from molecular polarizability components, have been proved to be useful to describe in a consistent way both size repulsion and dispersion attraction forces. The proposed potential model also allows one to isolate the role of the different intermolecular energy contributions. The spatial distribution of the CH(4) molecules in the clusters is investigated by means of molecular dynamics simulations under various conditions, even when methane phase transition from liquid to gas is likely to occur. In addition, several properties, such as radial distribution functions, density values, and mean diffusion coefficients, are analyzed in detail.

Influenza and SARS-coronavirus activating proteases TMPRSS2 and HAT are expressed at multiple sites in human respiratory and gastrointestinal tracts

The type II transmembrane serine proteases TMPRSS2 and HAT activate influenza viruses and the SARS-coronavirus (TMPRSS2) in cell culture and may play an important role in viral spread and pathogenesis in the infected host. However, it is at present largely unclear to what extent these proteases are expressed in viral target cells in human tissues. Here, we show that both HAT and TMPRSS2 are coexpressed with 2,6-linked sialic acids, the major receptor determinant of human influenza viruses, throughout the human respiratory tract. Similarly, coexpression of ACE2, the SARS-coronavirus receptor, and TMPRSS2 was frequently found in the upper and lower aerodigestive tract, with the exception of the vocal folds, epiglottis and trachea. Finally, activation of influenza virus was conserved between human, avian and porcine TMPRSS2, suggesting that this protease might activate influenza virus in reservoir-, intermediate- and human hosts. In sum, our results show that TMPRSS2 and HAT are expressed by important influenza and SARS-coronavirus target cells and could thus support viral spread in the human host.

Reactive processes in gas phase Na(+)-iso-C3H7Cl collisions: experimental guided-ion-beam and ab initio studies of the reactions on the ground singlet potential surface of the system up to 12.00 eV

Reactive processes, taking place when sodium ions collide with neutral iso-C(3)H(7)Cl molecules in the 0.02-12.00 eV range of energies in the center of mass frame, have been studied using an octopole radiofrequency guided-ion-beam apparatus developed in our laboratory. A dehydrohalogenation reaction channel leading to Na(C(3)H(6))(+) formation has been observed up to 1.00 eV while another process producing NaHCl(+) continues up to 4.00 eV. Furthermore, C(3)H(7)(+) formation resulting from decomposition of the reactants, ion-molecule adducts, has also been observed as well as its decomposition into C(2)H(3)(+) on increasing collision energy. Cross-section energy dependences for all these reactions have been obtained in absolute units. The ab initio electronic structure calculations have been done at the MP2 level for the colliding system ground singlet potential surface, giving information on the reactive surface main topological features. From the surface reactants side to the products' one, different potential wells and barriers have been characterized and their connectivity along the reaction evolution has been established using the intrinsic-reaction-coordinate method, thus interpreting the dynamical evolution of the reactants' collision complex to products. Experimental results demonstrate that NaHCl(+) can be produced via different channels. Reaction rate constants at 308.2 K for both dehydrohalogenation reactions have been calculated from measured excitation functions. It has been also confirmed that the reactants adduct decomposition giving C(3)H(7)(+) and NaCl takes place on the same potential surface. A qualitative interpretation of the experimental results in terms of ab initio calculations is also given.

Influence of diabetes on endothelial cell response during sepsis

AIMS/HYPOTHESIS

Several endothelial pathways of cell adhesion, coagulation and vascular endothelial growth factor (VEGF) signalling are activated during sepsis. The objective of this analysis was to investigate the influence of diabetes on biomarkers of endothelial cell activation in sepsis.

METHODS

This was a prospective observational cohort study of a convenience sample of adult patients (age ≥ 18 years) for whom infection was clinically suspected and who presented to an urban tertiary care emergency department between February 2005 and November 2008. We investigated the association of diabetes and sepsis with various endothelial activation biomarkers of cell adhesion (E-selectin, vascular cell adhesion molecule 1 [VCAM-1] and intercellular adhesion molecule 1 [ICAM-1]), coagulation (plasminogen activator inhibitor 1 [PAI-1]) and VEGF signalling (soluble fms-like tyrosine kinase-1 [sFLT-1]).

RESULTS

A total of 207 patients (34% with sepsis, 32% with severe sepsis and 34% with septic shock) were studied, including 63 (30%) with diabetes. Compared with patients without diabetes, patients with diabetes had significantly increased E-selectin and sFLT-1 levels overall; this was most pronounced during septic shock in the stratified analysis. Multivariate models including age, sex, sepsis severity and other variables as potential covariates confirmed the association of diabetes with elevated circulating plasma levels of E-selectin (standardised β 0.24, p < 0.001) and sFLT-1 (standardised β 0.19, p < 0.01), but there was no significant association with VCAM-1, ICAM-1 or PAI-1.

CONCLUSIONS/INTERPRETATION

During septic shock, patients with diabetes had higher levels of circulating biomarkers of endothelial cell adhesion (E-selectin) and VEGF signalling (sFLT-1). Future studies should address whether enhanced activation of the endothelium places patients with diabetes at increased risk for the development of sepsis and worsening morbidity and mortality.

Clinical evolution of patients with respiratory allergic disease due to sensitisation to Alternaria alternata being treated with subcutaneous immunotherapy

INTRODUCTION

Sensitisation to Alternaria is a cause of respiratory disease in Spain, particularly in childhood, but it is also a significant marker of the severity of this disease. Therefore, the use of an aetiological treatment (allergen specific immunotherapy) is essential, and both subjective and objective clinical parameters should be used to follow up this treatment.

OBJECTIVE

This open-label, uncontrolled, observational, prospective study was designed in order to study the evolution of these patients on allergen specific immunotherapy therapy in daily clinical practice and to assess the use of different monitoring tools.

MATERIAL AND METHODS

A total of 99 patients were included. They were monosensitised to this perennial allergen and treated with subcutaneous allergen specific immunotherapy. After one year of follow-up, these patients were assessed for the presence of symptoms, use of medication, clinical incidents, quality of life and asthma control.

RESULTS

After one year of treatment a significant fall was observed in the use of concomitant medication (β2-agonists: p=0.0278, inhaled corticosteroids: p=0.0007, anti-leukotrienes: p=0.0495), nasal symptoms (p=0.0081), quality of life (PAQLQ, p<0.0001) and asthma control (ACQ, p<0.0001). Twenty-one patients had to attend emergency department due to exacerbation of their allergic disease, and only one of them had to be admitted to hospital.

CONCLUSION

respiratory allergic disease due to Alternaria alternata is a disease which is hard to control, and in our daily practice, the use of specific subcutaneous immunotherapy can be of significant benefit in our paediatric patients.

Microarrays: Molecular allergology and nanotechnology for personalised medicine (II)

Progress in nanotechnology and DNA recombination techniques have produced tools for the diagnosis and investigation of allergy at molecular level. The most advanced examples of such progress are the microarray techniques, which have been expanded not only in research in the field of proteomics but also in application to the clinical setting. Microarrays of allergic components offer results relating to hundreds of allergenic components in a single test, and using a small amount of serum which can be obtained from capillary blood. The availability of new molecules will allow the development of panels including new allergenic components and sources, which will require evaluation for clinical use. Their application opens the door to component-based diagnosis, to the holistic perception of sensitisation as represented by molecular allergy, and to patient-centred medical practice by allowing great diagnostic accuracy and the definition of individualised immunotherapy for each patient. The present article reviews the application of allergenic component microarrays to allergology for diagnosis, management in the form of specific immunotherapy, and epidemiological studies. A review is also made of the use of protein and gene microarray techniques in basic research and in allergological diseases. Lastly, an evaluation is made of the challenges we face in introducing such techniques to clinical practice, and of the future perspectives of this new technology.

Guided-ion-beam and ab initio study of the Li+, K+, and Rb+ association reactions with gas-phase butanone and cyclohexanone in their ground electronic states

The association reactions between Li(+), K(+), and Rb(+) (M) and butanone and cyclohexanone molecules under single collision conditions have been studied using a radiofrequency-guided ion-beam apparatus, characterizing the adducts by mass spectrometry. The excitation function for the [M-(molecule)](+) adducts (in arbitrary units) has been obtained at low collision energies in the 0.10 eV up to a few eV range in the center of mass frame. The measured relative cross sections decrease when collision energy increases, showing the expected energy dependence for adduct formation. The energetics and structure of the different adducts have been calculated ab initio at the MP2(full) level, showing that the M(+)-molecule interaction takes place through the carbonyl oxygen atom, as an example of a nontypical covalent chemical bond. The cross-section energy dependence and the role of radiative cooling rates allowing the stabilization of the collision complexes are also discussed.

An experimental guided-ion-beam and ab initio study of the ion-molecule gas-phase reactions between Li+ ions and iso-C3H7Cl in their ground electronic state

Reactive collisions between Li(+) ions and i-C(3)H(7)Cl molecules have been studied in the 0.20-12.00 eV center-of-mass energy range using an octopole radio frequency guided-ion beam apparatus recently developed in our laboratory. At low collision energies, dehydrohalogenation reactions giving rise to Li(C(3)H(6))(+) and Li(HCl)(+) are the main reaction channels, while at higher ones C(3)H(7)(+) and C(2)H(3)(+) become dominant, all their reactive cross sections having been measured as a function of the collision energy. To obtain information about the potential energy surfaces (PESs) on which the reactive processes take place, ab initio calculations at the MP2 level have been performed. For dehydrohalogenations, the reactive ground singlet PES shows ion-molecule adduct formation in both the reactant and product sides of the surface. Following the minimum energy path connecting both minima, an unstable intermediate and the corresponding barriers, both lying below the reactant's energy, have been characterized. The entrance channel ion-molecule adduct is also involved in the formation of C(3)H(7)(+), which then generates C(2)H(3)(+) via an CH(4) unimolecular elimination. A qualitative interpretation of the experimental results based on ab initio calculations is also included.

The androgen-regulated type II serine protease TMPRSS2 is differentially expressed and mislocalized in prostate adenocarcinoma

Transmembrane serine protease 2 (TMPRSS2) is an androgen-regulated member of the type two transmembrane protease (TTSP) family. Two other members of the TTSP family, matriptase and hepsin, are over-expressed in prostate adenocarcinoma and mechanistically influence cancer cell invasion and metastasis. This study was performed to determine TMPRSS2 protein expression in primary and metastatic prostate cancers. We developed a monoclonal antibody capable of the sensitive and specific detection of TMPRSS2 protein. TMPRSS2 regulation by androgen and presence in seminal fluid was measured. TMPRSS2 localization and expression was evaluated in 415 cases of primary prostate cancer and 144 prostate cancer metastases by immunohistochemistry. We determined that TMPRSS2 protein expression is regulated by androgens and that TMPRSS2 is a component of the normal seminal fluid proteome. TMPRSS2 protein is abundantly expressed in the prostate, with low levels in the epithelia of the colon, stomach, epididymis and breast. Pancreatic acini, hepatic bile ducts, testicular Leydig cells and the kidney also express TMPRSS2. In the prostate, TMPRSS2 protein is specifically localized to the secretory epithelium, with enhanced expression in the plasma membrane orientated towards the ductal lumen. TMPRSS2 expression was significantly higher in both neoplastic prostate and in the epithelium of prostatic hyperplasia compared to normal epithelium (p < 0.01). TMPRSS2 expression was further elevated in higher Gleason grade cancers (patterns 4 and 5) compared to pattern 3 (p = 0.04). Furthermore, in most high-grade cancers, TMPRSS2 was mislocalized, being expressed in the cytoplasm as well as in the cell membrane. Prostate cancer metastases also generally expressed high levels of TMPRSS2. In summary, the TMPRSS2 protease is expressed highly in primary and metastatic prostate cancers and is associated with tumour cell differentiation. Based on studies with the related proteins matriptase and hepsin, TMPRSS2 should be investigated for causal roles in prostate carcinogenesis.

Size-Specific Interaction of Alkali Metal Ions in the Solvation of M+−Benzene Clusters by Ar Atoms

The size-specific influence of the M+ alkali ion (M = Li, Na, K, Rb, and Cs) in the solvation process of the M+-benzene clusters by Ar atoms is investigated by means of molecular dynamic simulations. To fully understand the behavior observed in M+-bz-Ar(n) clusters, solvation is also studied in clusters containing either M+ or benzene only. The potential energy surfaces employed are based on a semiempirical bond-atom decomposition, which has been developed previously by some of the authors. The outcome of the dynamics is analyzed by employing radial distribution functions, studying the evolution of the distances between the Ar atoms and the alkali ion M+ or the benzene molecule for all M+-bz-Ar(n) clusters. For all members, in the M+-bz series, the benzene molecule (bz) is found to remain strongly bound to M+ even in the presence of solvent atoms. The radial distribution functions for the heavier clusters (K+-bz, Rb+-bz, and Cs+-bz), are found to be different than for the lighter (Na+-bz and Li+-bz) ones.

From Ar Clustering Dynamics to Ar Solvation for Na+−Benzene

The gradual evolution from cluster rearrangement to solvation dynamics is discussed by considering the rearrangement of n (n = 1, ..., 19) Ar atoms around Na+-benzene clusters and using an atom-bond potential energy surface. The nature of the bonding is discussed on the basis of the decomposition of the interaction energy and of the formation of the possible conformers. The benzene molecule is found to remain strongly bound to Na+ independently of the number of solvating rare-gas atoms, although due to the anisotropy of the interaction potential, the Ar atoms solvate the Na+-benzene cluster preferentially on the side of the cation. Other specific features of the solvation process are discussed.

Study of ab initio molecular data for inelastic and reactive collisions involving the H3+ quasimolecule

The lowest two ab initio potential energy surfaces (PES), and the corresponding nonadiabatic couplings between them, have been obtained for the H3+ system; the molecular data are compared to those calculated with the diatomic in molecules (DIM) method. The form of the couplings is discussed in terms of the topology of the molecular structure of the triatomic. The method of Baer is employed to generate "diabatic" states and the residual nonadiabatic couplings are calculated. The ab initio results for these are markedly different from the corresponding DIM data, and show the need to consider the third PES.

Atom−Bond Pairwise Additive Representation for Cation−Benzene Potential Energy Surfaces: An ab Initio Validation Study

The achievement of extensive and meaningful molecular dynamics simulations requires both the detailed knowledge of the basic features of the intermolecular interaction and the representation of the involved potential energy surface in a simple, natural and analytical form. This double request stimulated us to extend to ion-molecule systems a semiempirical method previously introduced for the description of weakly interacting atom-molecule aggregates and formulated in terms of atomic species-molecular bond interaction additivity. The method is here applied to the investigation of the prototypical M(+)-C6H6 systems (M = Li, Na, K, Rb and Cs) and some of its predictions are tested against accurate ab initio calculations. Such calculations have been performed by employing the MP2 method and large basis sets, privileging the description of the metal atoms. The agreement between potential energy scans semiempirically obtained and ab initio results is good for all the investigated geometries, thus showing that the adopted representation is in general able to reproduce all the main features of the potential energy surface for these systems. The role of the various noncovalent interaction components, as a function of the geometry and of the intermolecular distance in the M(+)-C6H6 complexes, is also investigated for a more detailed assessment of the results of the semiempirical method.

Inelastic electronic excitation and electron transfer processes in collisions between Mg(3S01) atoms and K+(S01) ions studied by crossed beams in the 0.10-3.80-keV energy range

Inelastic and charge-transfer excitation processes in collisions between ground-state neutral Mg atoms and K+ ions have been studied by means of a crossed molecular-beam technique. Decay fluorescent emissions from Mg(3 1P1),Mg(4 3S1), and Mg(3s(1)3d(1), 3(3)D3,2,1) as well as the phosphorescent emission due to Mg(3 3P1) have been observed from excited Mg atoms and the charge-transfer emission decays from K(4 2P 3/2,1/2), K(5 2P 3/2, 1/2), K(6 2S 1/2), and K(4 2D 5/2, 3/2) for excited K atoms. The corresponding absolute cross-sections values versus collision energy functions were determined in the 0.10-3.80 keV laboratory energy range. In order to interpret the experimental results, accurate ab initio full configuration-interaction calculations using pseudopotentials have been performed for the (Mg-K)+ system, giving a manifold of adiabatic singlet and triplet potential-energy curves correlating with the different collision channels, which allow a qualitative interpretation of the emission excitation functions measured for the different processes studied. A comparative study with other Mg-alkali ion systems previously studied is also included.

Regulation of hepatocyte activator inhibitor-1 expression by androgen and oncogenic transformation in the prostate

Hepatocyte activator inhibitor-1 (HAI-1) is a transmembrane serine protease inhibitor that regulates the conversion of latent to active hepatocyte growth factor (HGF). Studies supporting a role for the HGF pathway in prostate carcinogenesis prompted an analysis of HAI-1 expression in the prostate. Here we analyze the regulation of HAI-1 expression by androgen, oncogenic transformation, and cancer progression. Immunohistochemical analysis revealed that HAI-1 expression was restricted to prostate epithelium, where staining occurred primarily in basal and atrophic luminal epithelial cells. Compared to normal glands, HAI-1 expression was significantly increased in localized prostate cancer and was present in most prostate cancer metastases. HAI-1 protein expression levels were sensitive to androgen in normal epithelium but not in cancer. Although androgen did not increase HAI-1 protein expression levels in LNCaP cells, it decreased HAI-1 surface expression, consistent with previous data from our group (Martin DB, Gifford DR, Wright ME, Keller A, Yi E, Goodlett DR, Aebersold R, Nelson PS: Quantitative proteomic analysis of proteins released by neoplastic prostate epithelium. Cancer Res 2004, 64:347-355). HAI-1 overexpression in cancer was predictive of prostate-specific antigen recurrence (relative risk, 1.24). These results suggest that HAI-1 regulates the HGF Met axis on prostate epithelial cells and influences HGF mediated tumor invasion and metastasis.

Electronic excitation and charge transfer processes in collisions between Mg(3 1S0) atoms and Rb+(1S0) ions in the 0.07–4.00 keV energy range

Inelastic collision processes between neutral Mg atoms and Rb(+) ions, both in their ground states, have been studied by means of a crossed molecular beam technique measuring the decay fluorescence of the excited species formed. Emissions corresponding to Mg(3 (1)P(1)), Mg(3 (3)D(3,2,1)), and Mg(4 (3)S(1)), formed by direct target excitation, Rb(5 (2)P(3/2,1/2)), Rb(6 (2)P(3/2,1/2)) produced by electron capture and also the phosphorescent emission due to decay of Mg(3 (3)P(1)), have been detected and the corresponding absolute cross-section values measured both as total values and resolved into their J states. No polarization measurements could be made. Ab initio calculations using pseudopotentials have been performed and from these a manifold of adiabatic energy curves correlating with the different entry and exit channels have been obtained, allowing to propose a qualitative interpretation of the results, such as the shape of the cross section vs energy for different transitions and the oscillating nature of the branching ratios due to interference effects.

Collagen-binding matrix proteins from elastomeric extraorganismic byssal fibers

The byssal threads of marine mussels represent a peculiar case of extraorganismic extracellular material. The threads consist of fibrous chimeric collagens such as preCol-P (with collagenous, elastin-like and histidine-rich domains) embedded in a microfibrillar matrix. We report here on the extraction, purification, and characterization of water-soluble proximal thread matrix protein 1 (PTMP1), which is preferentially located in the proximal portion of each byssal thread and decreases in a proximal to distal direction. PTMP1 has a mass of about 50 kDa as determined by matrix-assisted laser desorption-ionization with time-of-flight (MALDI-TOF) mass spectrometry. Glycine is the most common residue at 12.2 mol %, followed by asparagine/aspartic acid and glutamine/glutamic acid at 11.4 and 9.9 mol %, respectively. Glycosylation has been detected by Western blotting with biotinylated concanavalin A and neutral sugar analysis. With degenerate primers designed from the N-terminal sequence and an additional internal peptide derived by Lys-C endopeptidase digestion, a complete cDNA sequence for this protein was obtained by polymerase chain reaction (PCR) amplification of a Mytilus edulis foot cDNA library. Two variants with minor sequence differences limited to the N-terminus were found. The cDNA-deduced protein sequence reveals two symmetric internal repeats that together account for >85% of the protein. Sequence and epitope similarity of PTMP1 to the A domains of von Willebrand factor and integrin alpha(1)I suggest a capacity for collagen binding. Enzyme-linked immunosorbent assay (ELISA)-based measurement of PTMP1 binding to immobilized type I collagen shows high affinity (apparent K(D) = 0.25 microM), but the binding exhibits no dependence on metals. Using primers designed from M. edulis, we also found a PTMP1-like cDNA in a related species, M. galloprovincialis, with a deduced protein sequence having 97% identity with one M. edulis variant and 99% identity with the other. The corresponding cDNA sequences have 94% and 96% identity, respectively.

A molecular, morphometric and mechanical comparison of the structural elements of byssus from Mytilus edulis and Mytilus galloprovincialis

Marine mussels are renowned for their ability to produce an extra-organismic tendon-like structure that can withstand the wave forces associated with the intertidal habitat. Initial characterization of byssal properties has focused on Mytilus edulis, with few detailed comparisons with other mussels. M. galloprovincialis, a closely related species, provides an opportunity for a thorough comparison. Three full-length cDNA clones encoding the byssal collagens, precollagen D(preCol-D), preCol-NG and preCol-P, were isolated from M. galloprovincialis. Comparisons with M. edulis preCol-D,preCol-NG and preCol-P reveal a 91.3 %, 88.6 % and 90.1 % identity with the cDNA and an 89.0 %, 88.1 % and 89.0 % identity with the deduced protein sequences, respectively. Key elements are maintained between the species: in particular, modeled bends in the collagen helix due to breaks in the Gly-X-Y pattern and the location of cysteine and putative 3,4-dihydroxyphenylalanine (DOPA) residues. A potentially important difference between the two is that, in all cases, M. galloprovincialis byssal collagens contain additional histidine residues in their flanking domains. The significance of this may lie in the ability of M. galloprovincialisto utilize more metal chelate cross-links, which have been implicated in byssal thread stability.

M. edulis threads are typically twice the length and diameter of M. galloprovincialis threads and appear to contain nearly 10 % more collagen. These differences are maintained even when the different thread portions are compared. Despite differences in a number of parameters, most notably that whole M. galloprovincialis threads are stiffer, threads whether whole or separated into proximal and distal portions, have similar mechanical behaviors. It is apparent from this comparison that M. galloprovincialis and M. edulis are seemingly interchangeable models for byssal research.

Elastomeric gradients: a hedge against stress concentration in marine holdfasts?

The byssal threads of marine mussels are elastomeric fibres with a great capacity for absorbing and dissipating energy. Up to 70% of the total absorbed energy can be dissipated in the byssus. Because byssal threads attach the mussel to hard inert surfaces in its habitat, they must combine the need to be good shock absorbers with appropriate matching of Young's modulus between living tissue and a hard sub-stratum such as stone - stiffnesses that can differ by five orders of magnitude. Recent data suggest that improved modulus matching and decreased stress concentration between different portions of the byssus is achieved by the use of protein gradients. Protein gradients in byssal threads are constructed using natural macromolecular chimeras having a central collagenous domain, variable flanking modules and histidine-rich amino and carboxy termini. Stiff silk-like flanking modules prevail distally, while at the animal end, rubbery modules resembling elastin predominate. In between the two thread ends there is a mix of both module types. The histidine-rich termini provide metal binding/cross-linking sites, while collagen domains may confer self-assembly on all parts of the structure. A graded axial distribution of flanking modules is expected to moderate stress concentration in joined materials having disparate moduli.

Aggressiveness and Competitive Fitness of Phytophthora infestans Isolates Collected from Potato and Tomato in France

ABSTRACT To test the hypothesis that host-related differences in the genotypic composition of populations of the late blight pathogen Phytophthora infestans can be explained by differential pathogenicity, the aggressiveness of isolates of the pathogen collected in France from potato and tomato was measured on detached leaflets of potato (cv. Bintje) and tomato (cv. Marmande). A preliminary trial with four isolates (two each from potato and tomato) showed that lesion appearance and development were similar for each isolate in detached leaflets and in whole plant tests in growth cabinets. Isolates collected from tomato were more pathogenic to tomato than isolates collected from potato. This was particularly the case for isolates belonging to the A2 mating type. Isolates originating from potato had a higher infection efficiency and a higher sporulation capacity on this host, but they induced lesions that generally spread more slowly than those caused by isolates from tomato. Extensive variation for components of aggressiveness on potato, and to a lesser extent on tomato, was observed in collections of isolates from each of the two hosts. Competition experiments between one potato isolate and one tomato isolate in field plots of the susceptible potato cv. Bintje clearly demonstrated the higher competitive fitness of the potato isolate on its host of origin. Therefore, differential pathogenicity to potato and tomato certainly contributes to the differentiation between P. infestans populations present on potato and tomato in France; however, additional factors, possibly related to survival ability or random genetic drift, are probably also involved and may explain the persistence of weakly pathogenic isolates in these populations.

Post operative performance of racing Standardbreds treated arthroscopically for carpal chip fractures: 176 cases (1986-1993)

A retrospective study of 176 Standardbred horses that had arthroscopic surgery for carpal chip fractures over a 7 year period was done in order to determine fracture location and post operative performance. Chip fractures of the proximal third carpal bone and the distal radiocarpal bone occurred with equal frequency (49.2 and 49.6% respectively), and chip fractures involving the antebrachiocarpal joint were rare. Trotters had significantly more third carpal bone lesions than radiocarpal bone lesions when compared to pacers (P = 0.0304). Seventy-four per cent of horses made at least one start following surgery. Pacers were significantly more likely to have at least one start after surgery than were trotters (P = 0.0009). Median earnings per start significantly decreased after surgery (P = 0.0081), while median race mark significantly increased after surgery (P = 0.0100). It is concluded that the majority of Standardbreds will be useful racehorses following carpal arthroscopy; however, most earn less money per start and many race at a lower class.

A physiological evaluation of carbon sources for calcification in the octocoral Leptogorgia virgulata (Lamarck)

The union of calcium cations with carbonate anions to form calcium carbonate (CaCO3) is a fundamentally important physiological process of many marine invertebrates, in particular the corals. In an effort to understand the sources and processes of carbon uptake and subsequent deposition as calcium carbonate, a series of studies of the incorporation of 14C-labeled compounds into spicules was undertaken using the soft coral Leptogorgia virgulata. It has been surmised for some time that dissolved inorganic carbon in sea water is used in the biomineralization process. Furthermore, it was suspected that metabolically generated CO2 is also available for calcification. As a means of testing these possible sources of carbon in spicule calcification, key enzymes or transport systems in each pathway were inhibited. First, the enzyme carbonic anhydrase was specifically inhibited using acetazolamide. Second, the active transport of bicarbonate was inhibited using DIDS (4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid). Third, CO2 generation resulting from glycolysis and the citric acid cycle was arrested using iodoacetic acid, which interferes specifically with the enzyme glyceraldehyde-3-phosphate dehydrogenase. The results indicate that dissolved CO2 is the largest source of carbon used in the formation of calcitic sclerites, followed by HCO3- from dissolved inorganic carbon. In L. virgulata, the dissolved inorganic carbon is responsible for approximately 67% of the carbon in the sclerites. The other 33% comes from CO2 generated by glycolysis. Two important conclusions can be drawn from this work. First, carbon for spiculogenesis comes not only from dissolved inorganic carbon in the environment but also from metabolically produced carbon dioxide. While the latter has been theorized, it has never before been demonstrated in octocorals. Second, regardless of the carbon source, the enzyme carbonic anhydrase plays a pivotal role in the physiology of spicule formation in Leptogorgia virgulata.

FRAXE mutation analysis in three Spanish families

Very little is known about the phenotype of FRAXE-positive individuals and the relation between the genotype/phenotype and genotype/ cytogenetic expression. We describe three families with normal and mildly affected individuals and a severely retarded male expressing fragility at the FRAXE locus or presenting different expansions at the CGG FRAXE triplet. In addition, we analyze the FRAXE mutation in sperm DNA from a retarded male carrier with a handicapped daughter expressing fragility at the FRAXE locus. Mental status in FRAXE individuals is highly variable and, although mild mental retardation is observed in most cases, several carrier males are apparently normal. It seems that methylation is not as strictly associated with size of CGG triplets in the FRAXE locus as in FRAXA, and it is possible that normal carrier individuals with fully methylated increments in lymphocytes have a certain proportion of unmethylated alleles in the critical (i.e., neural) tissues, FRAXE mutation is apparently similar to FRAXA in that males with somatic large methylated increments are carriers of small unmethylated ones in germinal cells.

Regulation of FGF-4 enhancer activity by transcription factor NF-Y

Regulation of FGF-4 gene expression is controlled both by elements in the promoter and by an enhancer domain located in the untranslated region of the third exon. We have determined that transcription factor NF-Y binds to the FGF-4 promoter. We further show by mutational analysis that binding of NF-Y is essential for FGF-4 enhancer activity but has minimal effect on activity of the FGF-4 promoter alone.

[Infection with hepatitis B and C viruses in the mentally retarded]

AIM

To study the prevalence of hepatitis C virus infection (HCV) and the associated risk factors in an institution for the mentally retarded, in addition to its relation with hepatitis B infection (HBV).

METHODS

The presence of antibodies against the HCV (anti-HCV) and markers for the HBV was evaluated in 94 mentally retarded subjects admitted to a single institution. Information concerning the sex, age, length of admission, type and degree of mental retardation, history of sexual promiscuity, surgery and blood transfusions was collected in every individual.

RESULTS

The prevalence of infection by HBV was 22.3%. Only one individual was detected as being positive for the HCV.