Abstract 989: Spatial profiling of androgen receptor splice variant 7 transcriptional activity in prostate cancer metastases

Introduction: Androgen receptor splice variant 7 (AR-V7) is expressed in metastases from patients with castration resistant prostate cancer (CRPC) and shows a high level of inter- and intra-tumoral variability. However, the downstream activity generated by AR-V7 in tissue has not been shown. Whether AR-V7 is active in tissue or whether AR-V7 is a non-functioning biomarker with full-length AR is not known. To address this question, we constructed a tissue microarray (TMA) of 56 metastases from 27 patients with CRPC to analyze spatial gene expression using the GeoMx Digital Spatial Profiler. Immunostaining was performed to define epithelial, vascular, and stromal compartments. The stained tissues were then hybridized with barcoded tagged oligonucleotides targeting 2093 unique genes, which included those representing AR, AR-V cryptic exons, AR and neuroendocrine activity, and immune cell markers. One 500 um region of interest (ROI) was assessed per tissue core (approximately 1200 cells). A sequential section from the same TMA was then stained with AR-V7 and AR-C-terminal specific antibodies. ROIs for RNA and protein were selected to be similar between slides. In addition to DSP, each metastasis was assessed by RNA-seq on the bulk tissue.

Results: The most differentially expressed genes (FDR<0.05) based on association with AR-V7 staining were known downstream AR regulated genes including KLK2 and 3, FKBP5, NKX3.1, TMPRSS2, FASN, and TARP. Additionally, genes associated with proliferation and stemness, e.g., POLB, KRT1, SOX2, were significantly expressed. Since 93% of patients were on ADT at time of tissue collection and over 80% also had been treated with either abiraterone or enzalutamide, the increase in AR downstream genes would not be expected to occur from ligand activation of AR-FL. We also have previously shown that knock-down of AR-V7 in LNCaP95 cells results in loss of AR binding to AREs. In these metastases, then, activation of AR downstream genes would be a result of AR-V7 nuclear transport of AR-FL through AR-V7/AR-FL heterodimers or transcriptional activation by AR-V7 homodimers. Of further note, AR cryptic exons 1, 2, and 5 were also significantly expressed in AR-V7 positive ROIs (p< 0.0001). RNA-seq intron/exon junction reads were used to demonstrate that additional AR-Vs, most commonly AR-V9, were also expressed in tissues positive for AR-V7, suggesting that AR splicing is a common event in CRPC. Finally, expression of neuroendocrine (NE) genes INSM1 and TUBB2 were not expressed in AR-V7 positive ROIs (negatively correlated, p<0.001), indicating that AR-V7 and NE phenotypes cannot co-exist in the same cell.

Conclusion: AR-V7 continues to drive prostate cancer through activation of the AR-cistrome. Its expression is heterogenous in metastases along with NE cells, suggesting that in the presence of AR-V7 and NE markers, therapy needs to be directed at the N-terminus of AR and NE components.

Citation Format: Cynthia C. Sprenger, Ilsa Coleman, Michelle Kriner, Lauren Brady, Margaret Hoang, Martine Roudier, Mamatha Damodarasamy, Radhika Patel, Lawrence True, Peter Nelson, Michael Haffner, Stephen Plymate. Spatial profiling of androgen receptor splice variant 7 transcriptional activity in prostate cancer metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 989.

Inter- and intra-tumor heterogeneity of metastatic prostate cancer determined by digital spatial gene expression profiling

Metastatic prostate cancer (mPC) comprises a spectrum of diverse phenotypes. However, the extent of inter- and intra-tumor heterogeneity is not established. Here we use digital spatial profiling (DSP) technology to quantitate transcript and protein abundance in spatially-distinct regions of mPCs. By assessing multiple discrete areas across multiple metastases, we find a high level of intra-patient homogeneity with respect to tumor phenotype. However, there are notable exceptions including tumors comprised of regions with high and low androgen receptor (AR) and neuroendocrine activity. While the vast majority of metastases examined are devoid of significant inflammatory infiltrates and lack PD1, PD-L1 and CTLA4, the B7-H3/CD276 immune checkpoint protein is highly expressed, particularly in mPCs with high AR activity. Our results demonstrate the utility of DSP for accurately classifying tumor phenotype, assessing tumor heterogeneity, and identifying aspects of tumor biology involving the immunological composition of metastases.

The inter- and intra-tumor heterogeneity of metastatic prostate cancer (mPC) is underexplored. Here the authors use Digital Spatial Profiling to study gene and protein expression heterogeneity in 27 mPC patients, finding variation in associated pathways and potential immunotherapy targets.

Fundamental control of grade-specific colorectal cancer morphology by Src regulation of ezrin-centrosome engagement

The phenotypic spectrum of colorectal cancer (CRC) is remarkably diverse, with seemingly endless variations in cell shape, mitotic figures and multicellular configurations. Despite this morphological complexity, histological grading of collective phenotype patterns provides robust prognostic stratification in CRC. Although mechanistic understanding is incomplete, previous studies have shown that the cortical protein ezrin controls diversification of cell shape, mitotic figure geometry and multicellular architecture, in 3D organotypic CRC cultures. Because ezrin is a substrate of Src tyrosine kinase that is frequently overexpressed in CRC, we investigated Src regulation of ezrin and morphogenic growth in 3D CRC cultures. Here we show that Src perturbations disrupt CRC epithelial spatial organisation. Aberrant Src activity suppresses formation of the cortical ezrin cap that anchors interphase centrosomes. In CRC cells with a normal centrosome number, these events lead to mitotic spindle misorientation, perturbation of cell cleavage, abnormal epithelial stratification, apical membrane misalignment, multilumen formation and evolution of cribriform multicellular morphology, a feature of low-grade cancer. In isogenic CRC cells with centrosome amplification, aberrant Src signalling promotes multipolar mitotic spindle formation, pleomorphism and morphological features of high-grade cancer. Translational studies in archival human CRC revealed associations between Src intensity, multipolar mitotic spindle frequency and high-grade cancer morphology. Collectively, our study reveals Src regulation of CRC morphogenic growth via ezrin-centrosome engagement and uncovers combined perturbations underlying transition to high-grade CRC morphology. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Abstract P1-19-05: Capivasertib (AZD5363) in combination with fulvestrant in PTEN-mutant ER+ metastatic breast cancer

Background: Loss of function in the tumor suppressor gene, PTEN, activates PI3K/AKT signaling, driving tumor growth. Somatic mutations in PTEN occur in 5-10% of estrogen-receptor-positive (ER+) breast cancer (BC), and PTEN loss/inactivation is associated with an aggressive BC phenotype and poor outcome. Capivasertib, a pan-AKT kinase inhibitor, has shown antitumor activity in solid tumors. In ER+ BC, suppression of PI3K/AKT signaling results in a compensatory increase in ER-dependent transcription, potentially limiting the efficacy of AKT inhibitors when given as monotherapy. We therefore investigated concurrent inhibition of AKT and ER with combination therapy of capivasertib and fulvestrant in PTEN-mutant ER+ metastatic BC (MBC).

Methods: In an expansion cohort (part F) of a Phase I study (NCT01226316), oral capivasertib 400 mg twice daily, 4 days on 3 days off, and fulvestrant at labeled dose, was administered to ER+ MBC patients (pts) with tumors harboring a deleterious PTEN alteration (identified in tissue/plasma by local next-generation sequencing [NGS], with central NGS and immunohistochemistry [IHC] performed retrospectively). Pts were enrolled in fulvestrant-naïve (FN) or fulvestrant-resistant (FR) cohorts (max 24 pts/cohort). Key objectives included safety and efficacy based on 24-week clinical benefit rate (CBR).

Results: At data cut-off, 31 pts (12 FN; 19 FR) received treatment. Median number of prior metastatic regimens was 7. FN pts had higher rates of visceral disease (100%) and prior chemotherapy receipt (median 4 [range 0-8]) than FR pts (84%; median 2 [1-7]), respectively]. CBR and median progression-free survival (PFS) were 17% and 2.6 months in FN pts, and 37% and 4.1 months in FR pts, respectively (Table). Twenty-four patients (77%) had PTEN mutations and 7 (23%) had PTEN gene deletions determined by local NGS. Central plasma NGS confirmed 79% (19/24) of the PTEN mutations, and IHC confirmed complete loss of the PTENprotein in 85% (22/26) of cases. Treatment-related grade ≥3 adverse events (AEs) occurred in 32%, most frequently diarrhea and maculopapular rash (both n=2 pts). Treatment-related AEs resulted in dose reduction in 2 pts.

Table. Clinical efficacyFN, n=12FR, n=19ORR, % (95% CI)8 (0.2, 39)21 (6, 46)CBR, % (95% CI)17 (2, 48)37 (16, 62)Confirmed response, n (%)1 (8)4 (21)Stable disease ≥24 weeks, n (%)2 (17)3 (16)Median PFS, months (95% CI)2.6 (1.2–4.2)4.1 (1.5–6.7)Median duration of response, months (95% CI)5.5 (NC–NC)6.9 (1.4–NC)Data cut-off was 21 March 2019. Median time from last fulvestrant administration to study entry in FR pts (n=19) was 13.8 months (range 0.7–28.2). CBR was defined as confirmed responders and those with stable disease ≥24 weeks. NC, not calculable (because of limited pt numbers); ORR, objective response rate

Conclusions: Capivasertib plus fulvestrant is clinically active in heavily pretreated PTEN-mutated ER+ MBC, including in pts with prior resistance to fulvestrant. Efficacy appeared marginally better in FR than FN pts, possibly due to enrichment of pts with more aggressive disease in the FN cohort. Further analyses of the relationship between genomic features, such as concurrent mutations with drug activity, will be reported.

Citation Format: Lillian M Smyth, Gerald Batist, Funda Meric-Bernstam, Peter Kabos, Iben Spanggaard, Ana Lluch, Alison Schram, Andrea Varga, Andrea Wong, Helen Ambrose, Alan Barnicle, T. Hedley Carr, Elza C de Bruin, Carolina Salinas-Souza, Andrew Foxley, Joana Hauser, Justin PO Lindemann, Rhiannon Maudsley, Robert McEwen, Michele Moschetta, Martine Roudier, Gaia Schiavon, Pedram Razavi, Udai Banerji, Sarat Chandarlapaty, José Baselga, David M Hyman. Capivasertib (AZD5363) in combination with fulvestrant in PTEN-mutant ER+ metastatic breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-19-05.

Abstract 4541: MET gene copy number gains evaluated by NGS is more predictive than other methods to enrich for papillary RCC patients sensitive to savolitinib, a selective MET inhibitor

There is no approved therapy specifically for the treatment of papillary renal cell carcinoma (PRCC). Advances in molecular profiling of PRCC have identified a segment of PRCC with 10% MET mutation rates (Linehan et al 2016). Chromosome 7 gain is a hallmark of PRCC and thought to occur at 50% frequency in PRCC (Jiang et al 1998). We undertook a retrospective analysis of archival tumors to evaluate MET pathway aberrations for correlation with efficacy in a phase II study of savolitinib (volitinib, AZD6094, HMPL-504) in patients with PRCC (NCT02127710). Archival diagnostic tumor samples were mandated for central confirmation of PRCC diagnosis, histological subtyping, and for exploratory biomarker analysis. Eighty-four archival tumors were obtained and profiled using four methods: H&E stain for PRCC histological subtype, immunohistochemistry (IHC) for c-Met protein expression (Ventana, CONFIRM), fluorescent in situ hybridization (FISH) for MET gene amplification (Abbott, VYSIS), and Next Generation Sequencing (NGS) as an orthogonal method for confirmation of MET amplifications, detection of HGF gene amplifications, MET mutations, chromosome 7 ploidy, and other exploratory genomic biomarkers (Foundation Medicine Inc., T7 panel). Eight patients with a confirmed partial response (PR) to savolitinib were used to define MET-driven PRCC. Retrospective analysis demonstrated that only NGS, not IHC, FISH or histological subtype, identified all PRs. NGS detected any one of the following biomarkers alone or in combination in PRs: chromosome 7 copy number gain, MET or HGF gene focal amplification, MET kinase domain mutations. The frequency of these biomarkers in the phase II population were 31.5%, 10%, 1%, and 7.5%, respectively and captured all responders (18% ORR); however, 42% of non-responders (PD and SD) were also classified as MET-driven by NGS. Focal MET amplifications were confirmed with MET FISH testing, but FISH was unable to identify gains in chromosome 7. IHC was not as sensitive as NGS (57% vs 100%) but had a higher specificity. Molecular characterization of MET status was more predictive of response to savolitinib than a classification based on pathology.

Citation Format: Melanie M. Frigault, Sabina Signoretti, Aleksandra Markovets, Daniel Stetson, William Howat, Martine Roudier, Vincent Haddad, Brian Dougherty, Toni K. Choueiri, J. Carl Barrett. MET gene copy number gains evaluated by NGS is more predictive than other methods to enrich for papillary RCC patients sensitive to savolitinib, a selective MET inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4541.

The brain-penetrant clinical ATM inhibitor AZD1390 radiosensitizes and improves survival of preclinical brain tumor models

Poor survival rates of patients with tumors arising from or disseminating into the brain are attributed to an inability to excise all tumor tissue (if operable), a lack of blood-brain barrier (BBB) penetration of chemotherapies/targeted agents, and an intrinsic tumor radio-/chemo-resistance. Ataxia-telangiectasia mutated (ATM) protein orchestrates the cellular DNA damage response (DDR) to cytotoxic DNA double-strand breaks induced by ionizing radiation (IR). ATM genetic ablation or pharmacological inhibition results in tumor cell hypersensitivity to IR. We report the primary pharmacology of the clinical-grade, exquisitely potent (cell IC₅₀, 0.78 nM), highly selective [>10,000-fold over kinases within the same phosphatidylinositol 3-kinase-related kinase (PIKK) family], orally bioavailable ATM inhibitor AZD1390 specifically optimized for BBB penetration confirmed in cynomolgus monkey brain positron emission tomography (PET) imaging of microdosed ¹¹C-labeled AZD1390 (K_p,uu, 0.33). AZD1390 blocks ATM-dependent DDR pathway activity and combines with radiation to induce G₂ cell cycle phase accumulation, micronuclei, and apoptosis. AZD1390 radiosensitizes glioma and lung cancer cell lines, with p53 mutant glioma cells generally being more radiosensitized than wild type. In in vivo syngeneic and patient-derived glioma as well as orthotopic lung-brain metastatic models, AZD1390 dosed in combination with daily fractions of IR (whole-brain or stereotactic radiotherapy) significantly induced tumor regressions and increased animal survival compared to IR treatment alone. We established a pharmacokinetic-pharmacodynamic-efficacy relationship by correlating free brain concentrations, tumor phospho-ATM/phospho-Rad50 inhibition, apoptotic biomarker (cleaved caspase-3) induction, tumor regression, and survival. On the basis of the data presented here, AZD1390 is now in early clinical development for use as a radiosensitizer in central nervous system malignancies.

LuCaP Prostate Cancer Patient-Derived Xenografts Reflect the Molecular Heterogeneity of Advanced Disease an--d Serve as Models for Evaluating Cancer Therapeutics

BACKGROUND

Metastatic prostate cancer is a common and lethal disease for which there are no therapies that produce cures or long-term durable remissions. Clinically relevant preclinical models are needed to increase our understanding of biology of this malignancy and to evaluate new agents that might provide effective treatment. Our objective was to establish and characterize patient-derived xenografts (PDXs) from advanced prostate cancer (PC) for investigation of biology and evaluation of new treatment modalities.

METHODS

Samples of advanced PC obtained from primary prostate cancer obtained at surgery or from metastases collected at time of death were implanted into immunocompromised mice to establish PDXs. Established PDXs were propagated in vivo. Genomic, transcriptomic, and STR profiles were generated. Responses to androgen deprivation and docetaxel in vivo were characterized.

RESULTS

We established multiple PDXs (LuCaP series), which represent the major genomic and phenotypic features of the disease in humans, including amplification of androgen receptor, PTEN deletion, TP53 deletion and mutation, RB1 loss, TMPRSS2-ERG rearrangements, SPOP mutation, hypermutation due to MSH2/MSH6 genomic aberrations, and BRCA2 loss. The PDX models also exhibit variation in intra-tumoral androgen levels. Our in vivo results show heterogeneity of response to androgen deprivation and docetaxel, standard therapies for advanced PC, similar to the responses of patients to these treatments.

CONCLUSIONS

The LuCaP PDX series reflects the diverse molecular composition of human castration-resistant PC and allows for hypothesis-driven cause-and-effect studies of mechanisms underlying treatment response and resistance. Prostate 77: 654-671, 2017. © 2017 The Authors. The Prostate Published by Wiley Periodicals, Inc.

Epithelial mesenchymal-like transition occurs in a subset of cells in castration resistant prostate cancer bone metastases

TGFβ is a known driver of epithelial-mesenchymal transition (EMT) which is associated with tumor aggressiveness and metastasis. However, EMT has not been fully explored in clinical specimens of castration-resistant prostate cancer (CRPC) metastases. To assess EMT in CRPC, gene expression analysis was performed on 149 visceral and bone metastases from 62 CRPC patients and immunohistochemical analysis was performed on 185 CRPC bone and visceral metastases from 42 CRPC patients. In addition, to assess the potential of metastases to seed further metastases the mitochondrial genome was sequenced at different metastatic sites in one patient. TGFβ was increased in bone versus visceral metastases. While primarily cytoplasmic; nuclear and cytoplasmic Twist were significantly higher in bone than in visceral metastases. Slug and Zeb1 were unchanged, with the exception of nuclear Zeb1 being significantly higher in visceral metastases. Importantly, nuclear Twist, Slug, and Zeb1 were only present in a subset of epithelial cells that had an EMT-like phenotype. Underscoring the relevance of EMT-like cells, mitochondrial sequencing revealed that metastases could seed additional metastases in the same patient. In conclusion, while TGFβ expression and EMT-associated protein expression is present in a considerable number of CRPC visceral and bone metastases, nuclear Twist, Slug, and Zeb1 localization and an EMT-like phenotype (elongated nuclei and cytoplasmic compartment) was only present in a small subset of CRPC bone metastases. Mitochondrial sequencing from different metastases in a CRPC patient provided evidence for the seeding of metastases from previously established metastases, highlighting the biological relevance of EMT-like behavior in CRPC metastases.

Abstract 1718: The importance of clinically relevant rapid autopsy specimens and LuCaP patient-derived xenograft models to interrogate the heterogeneous and evolving treatment resistance of castration-resistant prostate cancer

Recent advances in our understanding of metastatic castration-resistant prostate cancer (mCRPC) biology have led to the approval and use of multiple novel drugs, including abiraterone, enzalutamide, cabazitaxel, sipuleucel-T and radium-223. Although these agents all provide improvement in survival, resistance always develops after an initial response. To understand the biology of responses and resistance, clinically relevant specimens and preclinical models are needed. To address this critical need, our objectives are: 1) to collect samples of metastases prior to and after treatment for evaluation of potential biomarkers of responses and resistance and 2) to generate patient-derived xenografts (PDXs) that are representative of these novel phenotypes of advanced mCRPC.

A Rapid Autopsy Program (RAP) was established at the University of Washington to study the lethal phenotype of mCRPC. Through the RAP we have collected more than 3000 tissue specimens, including bone and visceral metastases from over 110 patients who died of mCRPC. The samples were processed for paraffin embedding and frozen for future histological and molecular analyses. All samples are tracked in a relational database and cross-linked to clinical and pathologic data.

To provide clinically relevant preclinical models for studies of late stage advanced prostate cancer, we also implant tissues acquired during the RAP into immunocompromised mice in order to establish novel CRPC PDXs. At present we have 28 primary PDXs (the LuCaP series), and 10 castration-resistant sublines of the primary lines. The LuCaP models have been extensively characterized by light microscopy, immunohistochemistry, expression arrays, RNASeq, IHC, exome sequencing and other methodologies. We have also determined responses of these PDXs to castration and docetaxel. To address the need for models representing the current tumor phenotypes that exist in patients who develop resistance to secondary androgen-targeting therapy, we have also evaluated responses to abiraterone and enzalutamide, and are experimentally developing abiraterone- and enzalutamide-resistant LuCaP PDXs. In addition, we are continuing to generate novel PDXs using abiraterone- and enzalutamide-resistant patient samples, and have four models that were established from abiraterone-resistant tumors.

In summary, we have established a large biorepository of mCRPC specimens and PDXs. Moreover, due to the constant evolution of the advanced PCa phenotype we continue to acquire mCRPC specimens and establish novel PDXs that are refractory to the most recent treatments which allow us to investigate biology of late stage mCRPC and to provide valuable clinical specimens and LuCaP PDXs to the PCa research community.

Citation Format: Colm Morrissey, Ming H. Lam, Tia S. Higano, Lawrence D. True, Martine Roudier, Robert B. Montgomery, Peter S. Nelson, Paul H. Lange, Evan Y. Yu, Robert L. Vessella, Eva Corey. The importance of clinically relevant rapid autopsy specimens and LuCaP patient-derived xenograft models to interrogate the heterogeneous and evolving treatment resistance of castration-resistant prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1718. doi:10.1158/1538-7445.AM2015-1718

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.

Experimental Hamster Infection with a Strain of Leptospira borgpetersenii Ballum Isolated from a Reservoir Mouse in New Caledonia

Leptospirosis is a neglected zoonosis caused by pathogenic Leptospira. In this study, we characterized the virulence of isolate B3-13S obtained from a wild mouse (Mus musculus) captured in New Caledonia, subsequently identified as a bacterium belonging to the L. borgpetersenii serogroup Ballum. Hamsters were infected with an intraperitoneal injection of 2 × 10(8) bacteria, resulting in severe histopathological organ damages consistent with tissue lesions previously observed with other strains. Hamsters were also injected with 1 × 10(8) or 5 × 10(7) bacteria and animals that recovered showed renal carriage of leptospires in concentrations similar to the bacterial load quantified in mouse kidneys, with urinary shedding of bacteria up to 4 weeks postinfection. The serogroup Ballum is increasingly reported in human leptospirosis, and these results highlight the use of the B3-13S isolate for the development of models resulting in either severe acute or chronic forms of the infection, allowing for better characterization of its pathogenesis.

Abstract 1989: SRRM4 and the loss of REST may promote the emergence of the neuroendocrine /neuronal phenotype in castration resistant prostate cancer

Introduction: Recent findings suggest that neuroendocrine/neuronal (NE) differentiation may be associated with the development of metastatic castration-resistant prostate cancer (CRPC). Our objective was to characterize the NE phenotype in CRPC.

Methods: Using specimens obtained at rapid autopsy at the University of Washington, 2 tissue microarrays were made from (1) 155 metastatic sites from 50 autopsy patients who died from CRPC and (2) 24 LuCaP prostate cancer xenografts. NE markers, including Chromogranin A (CHGA), Synaptophysin (SYN), androgen receptor (AR), and prostate specific antigen (PSA) were analyzed by immunohistochemistry (IHC). To characterize the molecular features of the NE phenotype in CRPC, transcript levels in 78 corresponding metastatic sites and 24 LuCaP xenografts were determined by hybridization to whole genome microarrays.

Results: Co-expression of CHGA and SYN (by at least >10% of cells) was observed in 22 of 155 sites (11 sites were AR-). PSA, a surrogate of AR activity, was absent in all NE CRPC tumors that did not express AR. Four of the 24 LuCaP xenografts displayed an NE phenotype (all were AR-). Gene expression data were generated from 78 laser captured metastases, and 24 LuCaP xenografts. Five metastatic sites were CHGA+, SYN+ and AR-, and 5 were CHGA+, SYN+ and AR+, 4 LuCaP xenografts were CHGA+, SYN+ and AR- by IHC. Only CHGA+, SYN+ sites had a NE transcript signature, with the CHGA+, SYN+ and AR- specimens expressing a greater number of genes associated with the NE phenotype. In addition, a decrease in the expression of REST was observed in the 10 CHGA+, SYN+ metastatic sites and LuCaP xenografts. SRRM4 transcript expression was associated with the NE signature in 5 of the 6 CHGA+, SYN+ patients and the LuCaP xenografts. Furthermore RT-PCR comparing the epithelial to the NE LuCaP xenografts correlated the expression of SRRM4 with a splice variant of REST that lacks the repressor domain and the NE phenotype.

Conclusions: Our data suggest that a) the CRPC NE phenotype can be defined by CHGA+, SYN+ dual positivity and is more common in CRPC than historically in hormone sensitive primary disease, b) NE status from different sites in the same patient can be heterogeneous c) the NE phenotype is not necessarily associated with the loss of AR activity, and d) the loss of REST expression or the splicing of REST through the activity of SRRM4 could promote the NE phenotype in CRPC. These molecular studies suggest that evolution from hormone sensitive, to castration resistant on to NE disease involves the loss of REST or the loss of REST repressor activity due to alternate splicing by SRRM4.

Citation Format: Xiaotun Zhang, Ilsa Coleman, Roger Coleman, Lisha Brown, Lori Kollath, Lisly Chéry, Jared Lucas, Eva Corey, Martine Roudier, Paul Lange, Celestia Higano, Lawrence True, Peter Nelson, Robert Vessella, Colm Morrissey. SRRM4 and the loss of REST may promote the emergence of the neuroendocrine /neuronal phenotype in castration resistant prostate cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1989. doi:10.1158/1538-7445.AM2014-1989

Characterization of osteoblastic and osteolytic proteins in prostate cancer bone metastases

BACKGROUND

Approximately 90% of patients who die of Prostate Cancer (PCa) have bone metastases, which promote a spectrum of osteoblastic, osteolytic or mixed bone responses. Numerous secreted proteins have been reported to promote osteoblastic or osteolytic bone responses. We determined whether previously identified and/or novel proteins were associated with the osteoblastic or osteolytic response in clinical specimens of PCa bone metastases.

METHODS

Gene expression was analyzed on 14 PCa metastases from 11 patients by microarray profiling and qRT-PCR, and protein expression was analyzed on 33 PCa metastases from 30 patients by immunohistochemistry on highly osteoblastic and highly osteolytic bone specimens.

RESULTS

Transcript and protein levels of BMP-2, BMP-7, DKK-1, ET-1, and Sclerostin were not significantly different between osteoblastic and osteolytic metastases. However, levels of OPG, PGK1, and Substance P proteins were increased in osteoblastic samples. In addition, Emu1, MMP-12, and sFRP-1 were proteins identified with a novel role of being associated with either the osteoblastic or osteolytic bone response.

CONCLUSIONS

This is the first detailed analysis of bone remodeling proteins in human specimens of PCa bone metastases. Three proteins not previously shown to be involved may have a role in the PCa bone response. Furthermore, our data suggests that the relative expression of numerous, rather than a single, bone remodeling proteins determine the bone response in PCa bone metastases.

Sclerostin is expressed in articular cartilage but loss or inhibition does not affect cartilage remodeling during aging or following mechanical injury

OBJECTIVE

Sclerostin plays a major role in regulating skeletal bone mass, but its effects in articular cartilage are not known. The purpose of this study was to determine whether genetic loss or pharmacologic inhibition of sclerostin has an impact on knee joint articular cartilage.

METHODS

Expression of sclerostin was determined in articular cartilage and bone tissue obtained from mice, rats, and human subjects, including patients with knee osteoarthritis (OA). Mice with genetic knockout (KO) of sclerostin and pharmacologic inhibition of sclerostin with a sclerostin-neutralizing monoclonal antibody (Scl-Ab) in aged male rats and ovariectomized (OVX) female rats were used to study the effects of sclerostin on pathologic processes in the knee joint. The rat medial meniscus tear (MMT) model of OA was used to investigate the pharmacologic efficacy of systemic Scl-Ab or intraarticular (IA) delivery of a sclerostin antibody-Fab (Scl-Fab) fragment.

RESULTS

Sclerostin expression was detected in rodent and human articular chondrocytes. No difference was observed in the magnitude or distribution of sclerostin expression between normal and OA cartilage or bone. Sclerostin-KO mice showed no difference in histopathologic features of the knee joint compared to age-matched wild-type mice. Pharmacologic treatment of intact aged male rats or OVX female rats with Scl-Ab had no effect on morphologic characteristics of the articular cartilage. In the rat MMT model, pharmacologic treatment of animals with either systemic Scl-Ab or IA injection of Scl-Fab had no effect on lesion development or severity.

CONCLUSION

Genetic absence of sclerostin does not alter the normal development of age-dependent OA in mice, and pharmacologic inhibition of sclerostin with Scl-Ab has no impact on articular cartilage remodeling in rats with posttraumatic OA.

Abstract 406: Characterizing the molecular features of the neuroendocrine phenotype in castration resistant prostate cancer

Metastatic castration-resistant prostate cancer (CRPC) has a poor prognosis and remains a significant therapeutic challenge. Understanding the conversion from hormone sensitive to castration resistance may promote the development of more effective therapies. Recent findings suggest that neuroendocrine (NE) differentiation may be associated with the development of CRPC. Our objective was to characterize the NE phenotype in CRPC.

Using specimens obtained at radical prostatectomy and rapid autopsy at the University of Washington, 2 sets of tissue microarrays were made from 50 radical prostatectomies and 155 metastatic sites from 50 autopsy patients who died from CRPC (with up to 4 metastatic sites from each patient). NE markers, including Chromogranin A (CHGA), Neuron specific enolase (NSE) and Synaptophysin (SYN), as well as androgen receptor (AR) and prostate specific antigen (PSA) were analyzed by immunohistochemistry (IHC). To characterize the molecular features of the NE phenotype in CRPC, 78 corresponding metastatic sites were also assessed by Agilent gene expression analysis.

IHC revealed that only 2 of 50 primary prostate cancers had >10% CHGA positive cells whereas 7 of 50 primary prostate cancers 1-10% of cells expressed CHGA and all 50 were AR positive. By contrast, 29 of 50 CRPC autopsy patients had at least 1 CHGA+ metastasis; 53 of 155 metastatic sites had >10% CHGA positive cells (11 sites were AR negative), and 7 had 1-10% CHGA positive cells. Compared to primary prostate carcinomas, CRPC metastases had an increase in the frequency of CHGA+ expression (4% vs. 58%, p<0.001). Two other NE markers were also highly expressed by >10% of cells in each of the CRPC metastases. Of 155 CRPC metastases: 28 were positive for SYN and 47 were positive for NSE. Co-expression of CHGA and SYN was observed in 22 sites from 10 patients (10 sites did not express AR) and co-expression of CHGA, SYN and NSE was observed in 12 sites from 6 patients (6 sites did not express AR). PSA, a surrogate of AR activity, was absent in all NE CRPC tumors that did not express AR. All AR negative sites (12/155) expressed at least one NE marker. Gene expression data were generated from 78 laser captured metastases, which were grouped into 4 categories: 21 CHGA+ sites, 6 CHGA+, SYN+ and AR- sites, 5 CHGA+, SYN+ and AR+ sites, and 40 CHGA-, SYN-, NSE- and AR+ sites.

This study is the first extensive analysis of the NE features of CRPC. Our data suggest that a) the NE phenotype (as defined by CHGA expression) is significantly more common in CRPC than in hormone sensitive primary disease, b) NE status from different sites in the same patient can be heterogeneous, and c) the NE phenotype is not necessarily associated with the loss of AR. These molecular studies suggest that evolution from hormone sensitive to castration resistant disease involves emergence of NE characteristics over time that may explain the behavior of true “androgen independent” disease.

Citation Format: Xiaotun Zhang, Ilsa Coleman, Roger Coleman, Khanhthy Doan, Martine Roudier, Lisly Chéry, Jennifer Noteboom, Celestia Higano, Lawrence D. True, Paul H. Lange, Peter S. Nelson, Robert L. Vessella, Colm Morrissey. Characterizing the molecular features of the neuroendocrine phenotype in castration resistant prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 406. doi:10.1158/1538-7445.AM2013-406

Abstract 5122: Characterizing the molecular features of ERG positive tumors in primary and castration resistant prostate cancer

Metastatic castration-resistant prostate cancer (CRPC) has a poor prognosis and remains a significant therapeutic challenge. Gene fusions between the TMPRSS2 gene and members of the ETS family of transcription factors (ERG, ETV-1 ETV-4 and 5) have been found in prostate cancer (PCa). In this study we hypothesized that the overexpression of ERG in PCa promotes the expression of common genes and pathways in nuclear ERG positive hormone sensitive primary PCa and metastatic CRPC tumors. Our objective was to identify these common genes and pathways.

Using LuCaP PCa xenografts developed at the University of Washington, specimens obtained at radical prostatectomy, and metastatic specimens obtained at rapid autopsy, 3 sets of tissue microarrays were made from 24 LuCaP PCa xenograft lines, 114 radical prostatectomies and 155 metastases from 50 autopsy patients who died from CRPC (with up to 4 metastases from each patient). Nuclear ERG expression was analyzed by immunohistochemistry (IHC). In addition, to characterize the molecular features of ERG expressing PCa, 24 LuCaP PCa xenografts, 24 radical prostatectomies, and 78 corresponding metastases were also assessed by Agilent gene expression analysis.

Consistent with previously published FISH and qRT-PCR analyses, IHC revealed that 7 of 24 LuCaP xenograft lines were nuclear ERG positive. Fifty-one of 114 primary prostate cancers were nuclear ERG positive. However, among the 155 CRPC metastases from 50 autopsy patients, 15 of 155 metastases had nuclear ERG positivity. These 15 metastases represent 7 of 50 patients with at least 1 nuclear ERG positive metastasis. This suggests that nuclear ERG expression is less frequent in CRPC than in hormone sensitive primary prostate carcinomas. Furthermore, not all metastases in a given patient were nuclear ERG positive. In addition, gene expression data was generated from 24 LuCaP PCa xenografts, 24 radical prostatectomies and 78 CRPC metastases, which were grouped into ERG positive and ERG negative metastases based on nuclear ERG positivity in the same tissue specimen by IHC. The gene expression profiles of the ERG positive and ERG negative cancer tissues are being analyzed to identify ERG regulated genes and ERG regulated pathways of interest.

This study is a comprehensive analysis of ERG expression and downstream effectors of ERG in xenograft models of PCa, primary PCa and CRPC. Our data suggest that ERG expression is less frequent in CRPC and nuclear ERG status can vary from site to site within a CRPC patient. The gene expression studies will further define the role of ERG in PCa.

Citation Format: Martine Roudier, Ilsa Coleman, Xiaotun Zhang, Roger Coleman, Lisly Chéry, Lisha Brown, Bryce Lakely, Celestia Higano, Lawrence D. True, Paul H. Lange, Shiv Srivistava, Aykut Üren, Eva Corey, Robert L. Vessella, Peter S. Nelson, Colm Morrissey. Characterizing the molecular features of ERG positive tumors in primary and castration resistant prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5122. doi:10.1158/1538-7445.AM2013-5122

Abstract 305: The biological and molecular characterization of clinically relevant prostate cancer xenograft lines (LuCaP series), including responses to therapy

Introduction:

Prostate cancer (PCa) is a heterogeneous disease, which results in an unpredictable and varied response to therapy. A limitation in unraveling the complexities of PCa and developing / evaluating novel therapeutic strategies has been the lack of pre-clinical models that closely replicate this heterogeneity. To overcome this limitation we have established over 3 dozen PCa xenograft lines (LuCaP series).

Methods:

Characterization of the xenograft lines derived from PCa primaries and metastases includes: (a) growth properties, (b) expression of 45 biomarkers by immunohistochemistry (IHC), (c) gene expression, (d) copy number gains and losses, (e) expression of the androgen receptor (AR) and its splice variants, (f) bone response (i.e. osteoblastic, osteolytic or mixed), and (g) response to therapy, i.e. androgen ablation, docetaxel and anti-IGF-1R.

Results:

Forty distinct xenograft lines comprise the current LuCaP panel. Four are neuroendocine, 12 are castration resistant (CR) sublines and 7 are abiraterone or MDV-3100 resistant sublines. Comprehensive characterization studies have been done on 24 lines. All lines histologically resemble the originating clinical specimen. Unsupervised gene expression array clustering analyses revealed (a) association between the xenograft and the originating clinical specimen, (b) pairing of androgen-sensitive lines with their CR sublines, (c) a distinction between adenocarcinoma and neuroendocrine phenotypes and (d) insignificant drift over a 2-5 year period of serial passage. Biomarker expression is quite heterogeneous and in most cases, protein expression correlated well with gene expression.

Importantly, 7 LuCaP models elicit an osteoblastic reaction in the bone, 5 models are PTEN negative, and 8 lines have the TMPRSS2:ERG fusion. The xenograft lines express different levels of AR with some expressing AR splice variants.

Heterogeneity was also observed in responses to therapy; prolonged survival (PS) following androgen ablation or docetaxel treatment ranged from 1 - 7 fold. Interestingly, LuCaP 86.2, expressing predominantly ARv567es, was among the least responsive to androgen ablation (PS 1.1) whereas it is one of the most responsive to docetaxel (PS >4). Several novel anti-androgen therapies are currently under investigation as individual agents and in combination; heterogeneous responses are being observed. To explore mechanisms of resistance, we are also maintaining sublines that developed resistance to abiraterone and MDV-3100.

Conclusions: These LuCaP PCa xenograft lines are highly diverse and clinically relevant models to study PCa biology and to evaluate new treatment modalities. The diversity of phenotypes and responses to therapy most importantly suggests that misleading conclusions can be drawn from the use of only one or two models in preclinical evaluations.

Citation Format: Holly Nguyen, Eva Corey, Colm Morrissey, Peter Nelson, Xiaotun Zhang, Martine Roudier, Stephen Plymate, Lawrence True, Celestia Higano, Robert Montgomery, Paul Lange, Robert Vessella. The biological and molecular characterization of clinically relevant prostate cancer xenograft lines (LuCaP series), including responses to therapy. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 305. doi:10.1158/1538-7445.AM2013-305

Abstract 1532: The identification of osteoblastic and osteolytic factors in prostate cancer bone metastases

Prostate Cancer (PCa) metastasizes to the bone in approximately 90% of patients who die of PCa. Growth of tumor cells in the bone can lead to replacement of bone marrow, spinal cord compression, severe bone pain, cachexia and death. The bone response to a metastasis can manifest as a spectrum of osteoblastic to osteoblastic/osteolytic (mixed) or osteolytic responses in the same patient at different biopsy sites. A number of proteins have been proposed to promote the osteoblastic and osteolytic responses in PCa bone metastasis. Our objective was to determine whether known bone forming and degrading factors are associated with the osteoblastic or osteolytic response in pre-clinical models and clinical specimens of PCa bone metastasis. Additionally, we wanted to identify novel proteins that may be associated with the osteoblastic and osteolytic response in PCa bone metastases. Using specimens obtained at rapid autopsy at the University of Washington, we compared the gene expression profile of osteoblastic and osteolytic metastases (n=14) from 13 patients and validated our findings by qRT-PCR. We also interrogated the same factors at the protein level in 18 osteoblastic and 18 osteolytic PCa bone metastases from 27 patients by immunohistochemistry (IHC). Additionally, we are currently interrogating the levels of these factors in 6 novel LuCaP xenograft models of PCa that promote an osteoblastic response and 4 that promote an osteolytic response in the tibia of immune compromised mice by IHC. Using gene expression arrays, validated by qRTPCR, we identified a putative osteoblastic factor EMID1 (p=0.01) and two putative osteolytic factors, MMP12 (p=0.03) and sFRP1 (p=0.02). By IHC, MMP12 expression approached significance (p=0.07), whereas sFRP1 was significantly higher in the osteolytic samples (p=0.02). Interestingly, we did not observed significant differences in transcript levels between osteoblastic and osteolytic metastases for a number of proposed osteoblastic and osteolytic factors including BMP2 and 7, tachykinin 1, endothelin 1, osteoprotegerin, and sclerostin. Furthermore, none of the proposed osteoblastic and osteolytic factors we interrogated by IHC showed a significant difference in protein expression between osteoblastic and osteolytic PCa bone metastases. This is the first detailed analysis of PCa osteoblastic and osteolytic factors in human specimens and animal models of PCa in the bone. Our data suggest that many of the factors important in bone remodeling may not be central to the bone response in PCa bone metastases. Additionally we have identified three factors that may have a role in bone remodeling in PCa bone metastases.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1532. doi:1538-7445.AM2012-1532

Abstract C34: The biological and molecular characterization of 28 unique prostate cancer xenograft lines (LuCaP series), including responses to therapy

Introduction: Prostate cancer (PCa) is a heterogeneous disease which results in an unpredictable and wide range of responses to therapy. A significant limitation in unraveling the complexities of PCa and developing / evaluating novel therapeutic strategies is the lack of pre-clinical models that closely replicate the diversity of the disease seen in man. To overcome this limitation we have established over 2 dozen PCa xenograft lines (LuCaP series). This poster will provide a summary of the biological and molecular characterization of nearly all of these xenograft lines including their responses to therapy.

Methods: Characterization of the xenograft lines derived from primary PCa and PCa metastases includes: (a) basic histology, (b) serum PSA levels, (c) tumor doubling time, (d) expression of 38 biomarkers by immunohistology (IHC), (e) oligo array profiles, (f) expression of the androgen receptor (AR) and its splice variants, (g) bone response, and (h) response to therapy, i.e. androgen ablation, docetaxel and anti-IGF-1R.

Results: Of the 28 derived LuCaP xenograft lines, 24 are adenocarcinoma and 4 are neuroendocrine. Our results show that all lines histologically resemble the originating clinical specimen. Unsupervised gene expression array clustering analyses revealed (a) association between the xenograft and the originating clinical specimen, (b) pairing of androgen-sensitive lines with their castration-resistant offspring, (c) a distinction between adenocarcinoma and neuroendocrine phenotypes and (d) that gene expression profiles were not significantly altered by continuous passage in vivo for 2-8 years.

Importantly, seven of our models elicit an osteoblastic reaction in the bone, five models are PTEN negative, eight lines have the TMPRSS2:ERG fusion, and there are eight matched pairs of androgen-sensitive and castration-resistant xenografts.

As in the clinical scenario, the xenograft lines display considerable diversity. They express variable amounts of PSA (range from 0-1000 ng/ml/1 g), different levels of AR and express an AR splice variant after castration. IHC revealed considerable heterogeneity in all biomarkers evaluated. In most cases protein expression correlated well with gene expression.

Heterogeneity was also observed in responses to therapy; prolonged survival (PS) following androgen ablation or docetaxel each ranged from 1 - 7.3 fold. Interestingly, LuCaP 86.2, expressing predominantly ARv567es, was among the least responsive to androgen ablation (PS 1.1) whereas it is one of the most responsive to docetaxel (PS >4). Several novel anti-androgen therapies are currently under investigation.

Conclusions: These 28 LuCaP PCa xenograft lines are highly diverse and clinically relevant models to study PCa biology and evaluate new treatment modalities. The diversity of phenotypes and responses to therapy most importantly suggests that misleading conclusions can be drawn from the use of only one or two PCa models in preclinical evaluations. Use of multiple models is extremely important in the evaluation of new therapeutic strategies, especially those targeting specific pathways.

Citation Format: Holly Nguyen, Martine Roudier, Lawrence True, Robert Vessella, Eva Corey, Colm Morrissey, Peter Nelson, Xiaotun Zhang, Stephen Plymate, Celestia Higano, Paul Lange. The biological and molecular characterization of 28 unique prostate cancer xenograft lines (LuCaP series), including responses to therapy [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr C34.

Inhibition of RANKL increases the anti-tumor effect of the EGFR inhibitor panitumumab in a murine model of bone metastasis

Bone metastases cause severe skeletal complications and are associated with osteoclast-mediated bone destruction. RANKL is essential for osteoclast formation, function, and survival, and is the primary effector of tumor-induced osteoclastogenesis and osteolysis. RANKL inhibition by its soluble decoy receptor osteoprotegerin (OPG) prevents tumor-induced osteolysis and decreases skeletal tumor burden. Because osteoclast-mediated bone resorption releases growth factors from the bone matrix, the host bone microenvironment induces a vicious cycle of bone destruction and tumor proliferation and survival. A prediction of this vicious cycle hypothesis is that targeting the host bone microenvironment by osteoclast inhibition would reduce tumor growth and survival and may enhance the anti-tumor effects of targeted therapies. The epidermal growth factor receptor (EGFR) pathway regulates critical processes such as cell growth and survival, and anti-EGFR therapies can cause tumor cell arrest and apoptosis. We evaluated whether reduction of osteolysis by RANKL inhibition could enhance the anti-tumor effects of an anti-EGFR antibody (panitumumab) in a novel murine model of human A431 epidermoid carcinoma bone metastasis. Skeletal tumor progression was assessed longitudinally by bioluminescence imaging. RANKL inhibition by OPG-Fc treatment resulted in a reduction in tumor progression in bony sites. OPG-Fc treatment also caused a dose-dependent reduction in tumor-induced osteolysis, supporting the essential role of RANKL in this process. In combination, RANKL inhibition increased the anti-tumor efficacy of an anti-EGFR antibody, and completely blocked tumor-induced bone breakdown, demonstrating that addition of the indirect anti-tumor effect of RANKL inhibition increases the anti-tumor efficacy of panitumumab, a targeted anti-EGFR antibody.

Abstract 3242: The molecular and biological characterization of 25 unique prostate cancer xenograft lines, including response to therapy

Introduction: Prostate cancers (PCa) exhibit a wide range of molecular and biological profiles. In concert with this heterogeneity, there is a wide spectrum of responses to therapy. One of the significant limitations in unraveling the complexities of PCa and designing/evaluating novel therapeutic strategies has been the lack of pre-clinical models that closely replicate the diversity seen in man. To overcome this limitation we have developed 25 unique PCa xenograft lines (LuCaP series) where the initiating implants were derived from primary tumors, soft-tissue metastases and bone metastases. This presentation will provide details of a comprehensive molecular and biological characterization of these lines, including their responses to therapy.

Methods: Tumors were obtained either from radical prostatectomies or from our rapid autopsy program, which is designed specifically for the acquisition of metastatic foci. Tumor pieces were implanted into male, immune compromised mice. Characterization involves: (a) quantification of serum PSA levels, (b) basic histology, (c) tumor doubling time, (d) a panel of >15 biomarkers assessed by immunohistochemistry, (e) gene expression array profiles, (f) chromosomal losses and gains, (g) expression of the TMPRSS2:ERG fusion gene, (h) presence of the androgen receptor (AR) and its splice variants, (i) bone remodeling perturbations associated with tumor growth in bone, and (j) response to therapy, including androgen ablation and docetaxel.

Results: Overall, 18% of the attempts to establish xenografts were successful resulting in 25 lines. As in the clinical scenario, these xenografts display a wide range of characterization profiles. While most are adenocarcinomas, 3 are neuroendocrine and all histologically resemble the originating clinical specimen. PSA serum levels can reach into the low thousands of ng/ml for a 1 g tumor. AR gene and protein expression is highly variable and >50% of the lines express a constitutively active AR splice variant. The gene expression profiles show multiple clustering patterns that include a close association of the xenograft with the clinical specimen, pairing of androgen dependent lines with their castrate-resistant offspring and a distinction between adenocarcinoma and neuroendocrine histologies. Five of the lines are PTEN negative and 9 express the TMPRSS2:ERG gene fusion. The bone remodeling response ranges from osteoblastic to lytic. Responses to androgen ablation and docetaxel range from long duration to no response.

Conclusions: These 25 LuCaP PCa xenograft lines provide a highly diverse, yet clinically relevant, panel for the study of PCa biology. This diversity most importantly suggests that misleading conclusions can be drawn from use of only one or two PCa models. This is extremely important in the evaluation of new therapeutic strategies, especially those that target specific pathways.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3242.

Abstract 3302: Profiling prostate cancer metastases

Introduction: Prostate cancer (PCa) metastasizes to a number of sites, however, it has a propensity to metastasize to bone. There is considerable variation in sites of metastases, the phenotype of metastases, and bone response in PCa. Our objective was to detail the behavior of PCa metastases in a large cohort of patients who have died of PCa.

Methods: Tissue samples used in this study were obtained from seventy patients who had died from advanced PCa and who underwent a rapid autopsy, which was performed under the aegis of the Prostate Cancer Donor Program at the University of Washington. We evaluated the clinical history, sites of metastasis, pathology, biomarker expression and bone response for all 70 patients. We used laser capture microdissection to isolate mRNA from liver, lymph node and bone metastases and performed expression analyses on AgilentTM Oligo Arrays (n=32). Tissue microarrays were used to determine the number of neuroendocrine metastases, androgen receptor positivity, androgen-associated protein expression, and PCa proliferation rates (Ki-67) from 42 patients. Histomorphometry was used to evaluate bone response in ∼20 predetermined bone biopsy sites from 50 of the patients.

Results: PCa bone metastases occurred in 90% of our patients that died of PCa. Additionally, the majority of bone metastases were predominantly osteoblastic 71%, with 20% predominantly osteolytic and 9% with a mixed or no bone response. The predominant non-bone sites were lymph nodes, liver, lung and adrenal glands respectively. Seven of 42 patients had metastases with a neuroendocrine phenotype. Nuclear androgen receptor expression was high in bone and low in liver metastases and the correlation between nuclear AR and cytoplasmic PSA was 0.49. Proliferation rates were low in normal prostate increasing in Gleason 3 through 4, and higher in metastases. In a preliminary expression analysis we observed significantly higher expression of CD302, ZNF329, and TMEM79 in the PCa bone metastases compared to soft tissue metastases. Interestingly, bone histomorphometry revealed that the number of TRAcP positive osteoclasts was halved in bone cores from patients treated with bisphosphonates (n=459) compared to bone cores from non-bisphosphonate treated patients (n=284) (p=0.0003).

Conclusions: The heterogeneity of PCa metastases both within and between patients is a considerable obstacle in determining the appropriate treatment regime for each individual. Our data highlight these differences, while suggesting patients may be grouped into cohorts with consistent molecular signatures and clinical outcomes.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3302.

Combined therapy with the RANKL inhibitor RANK-Fc and rhApo2L/TRAIL/dulanermin reduces bone lesions and skeletal tumor burden in a model of breast cancer skeletal metastasis

In bone metastases, tumor cells interact with the bone microenvironment to induce osteoclastogenesis, leading to bone destruction and the growth factor release.  RANK ligand (RANKL) is essential for osteoclast formation, function, and survival.  Tumor cell-mediated osteolysis is thought to occur ultimately via induction of RANKL within the bone stroma, and inhibition of RANKL in models of breast cancer bone metastases blocks tumor-induced osteolysis and reduces skeletal tumor burden.  In addition, the skeleton is co-opted by tumor cells and functions as a supportive tumor microenvironment.  Inhibition of RANKL, by reducing tumor-induced osteoclastogenesis, may reduce the local release of growth factors and calcium which may potentially enhance the anti-tumor activity of cytotoxic or direct tumor apoptotic agents.  Recombinant human Apo2 ligand/ TNF-related apoptosis-inducing ligand (rhApo2L/TRAIL/dulanermin) is a dual pro-apoptotic receptor agonist that preferentially induces apoptosis in cancer cells versus normal cells.  We therefore examined RANKL inhibition (using RANK-Fc) in combination with rhApo2L/TRAIL on tumor-induced osteolysis and skeletal tumor burden in a murine intracardiac injection model of MDA-MB-231 breast carcinoma bone metastasis.  rhApo2L/TRAIL treatment resulted in a rapid reduction of skeletal tumor burden. Treatment with RANK-Fc prevented osteolytic lesions and reduced skeletal tumor burden. Combining RANK-Fc with rhApo2L/TRAIL was superior to either rhApo2L/TRAIL or RANK-Fc alone at reducing skeletal tumor burden in the bone metastasis model.  Our findings show that RANKL inhibition effectively inhibits pathologic osteolysis induced by human breast adenocarcinoma MDA-MB-231 cells in animals with established tumors, and also enhances the ability of rhApo2L/TRAIL to reduce skeletal tumor burden in vivo.

Denosumab for the treatment of giant cell tumor (GCT) of bone: Final results from a proof-of-concept, phase II study

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Background: GCT of bone is a primary osteolytic bone tumor with low metastatic potential that is associated with significant skeletal morbidity. GCT is rich in stromal cells that express RANKL, a key mediator of osteoclast activation. In this open-label, study, we investigated whether denosumab, a fully human monoclonal antibody against RANKL, could have a potential therapeutic effect on giant cell histology for patients with GCT. Methods: In this single-arm study, 37 patients with measurable or unresectable GCT received denosumab 120 mg subcutaneously once monthly with loading doses on days 8 and 15 of month 1. The primary endpoint was the proportion of patients with a tumor response (≥90% elimination of giant cells or no radiographic progression of the target lesion) at week 25 as assessed by histology and CT or MRI. A sample size of 35 patients was planned. All 37 enrolled patients were evaluated for safety; 35 were eligible for efficacy evaluation (2 had insufficient histology or radiology data). Results: Thirty of 35 patients (86%; 95% CI 70%-95%) had a tumor response: 20 of 20 by histology and 10 of 15 by radiology. Of 31 patients with data for assessments of clinical benefit, 26 (84%%; 95% CI 66%-95%) reported reduced pain or improvement in functional status. Bone repair was reported in 9 patients (29%; 95% CI 14%-48%). Suppression of the bone turnover markers urinary N-telopeptide and serum C-telopeptide was seen as early as 28 days after the first dose and sustained for the duration of the study. Adverse events (AEs) were reported in 33 patients (89%). One death due to surgical complications (not treatment-related) occurred on-study. No patient experienced treatment-related serious AEs or developed anti-denosumab antibodies. Conclusions: In this study, 86% of patients with measurable or unresectable GCT experienced a tumor response with denosumab. Further clinical trials of denosumab as a new therapy for GCT are warranted.

[Table: see text]

RANK ligand inhibition plus docetaxel improves survival and reduces tumor burden in a murine model of prostate cancer bone metastasis

Tumor cells induce excessive osteoclastogenesis, mediating pathologic bone resorption and subsequent release of growth factors and calcium from bone matrix, resulting in a "vicious cycle" of bone breakdown and tumor proliferation. RANK ligand (RANKL) is an essential mediator of osteoclast formation, function, and survival. In metastatic prostate cancer models, RANKL inhibition directly prevents osteolysis via blockade of osteoclastogenesis and indirectly reduces progression of skeletal tumor burden by reducing local growth factor and calcium concentrations. Docetaxel, a well-established chemotherapy for metastatic hormone-refractory prostate cancer, arrests the cell cycle and induces apoptosis of tumor cells. Suppression of osteoclastogenesis through RANKL inhibition may enhance the effects of docetaxel on skeletal tumors. We evaluated the combination of the RANKL inhibitor osteoprotegerin-Fc (OPG-Fc) with docetaxel in a murine model of prostate cancer bone metastasis. Tumor progression, tumor area, and tumor proliferation and apoptosis were assessed. OPG-Fc alone reduced bone resorption (P < 0.001 versus PBS), inhibited progression of established osteolytic lesions, and reduced tumor area (P < 0.0001 versus PBS). Docetaxel alone reduced tumor burden (P < 0.0001 versus PBS) and delayed the development of osteolytic lesions. OPG-Fc in combination with docetaxel suppressed skeletal tumor burden (P = 0.0005) and increased median survival time by 16.7% (P = 0.0385) compared with docetaxel alone. RANKL inhibition may enhance docetaxel effects by increasing tumor cell apoptosis as evident by increased active caspase-3. These studies show that inhibition of RANKL provides an additive benefit to docetaxel treatment in a murine model of prostate cancer bone metastasis and supports clinical evaluation of this treatment option in patients.

Targeted expression of csCSF-1 in op/op mice ameliorates tooth defects

OBJECTIVE

The aim of this study was to characterize the tooth phenotype of CSF-1-deficient op/op mice and determine whether expression of csCSF-1 in these mice has a role in primary tooth matrix formation.

DESIGN

Ameloblasts and odontoblasts, isolated from wt/wt frozen sections using laser capture microdissection, were analysed for csCSF-1, sCSF-1 and CSF-1R mRNA by RT-PCR. Mandibles, excised from 8 days op/op and wt/wt littermates, were examined for tooth morphology as well as amelogenin and DMP1 expression using in situ hybridisation. op/opCS transgenic mice, expressing csCSF-1 in teeth and bone using the osteocalcin promoter, were generated. Skeletal X-rays and histomorphometry were performed; teeth were analysed for morphology and matrix proteins.

RESULTS

Normal dental cells in vivo express both CSF-1 isoforms and CSF-1R. Compared to wt/wt, op/op teeth prior to eruption showed altered dental cell morphology and dramatic reduction in DMP1 transcripts. op/opCS mice showed marked resolution of osteopetrosis, tooth eruption and teeth that resembled amelogenesis imperfecta-like phenotype. At 3 weeks, op/op teeth showed severe enamel and dentin defects and barely detectable amelogenin and DMP1. In op/opCS mice, DMP1 in odontoblasts increased to near normal and dentin morphology was restored; amelogenin also increased. Enamel integrity improved in op/opCS, although it was thinner than wt enamel.

CONCLUSIONS

Results demonstrate that ameloblasts and odontoblasts are a source and potential target of CSF-1 isoforms in vivo. Expression of csCSF-1 within the tooth microenvironment is essential for normal tooth morphogenesis and may provide a mechanism for coordinating the process of tooth eruption with endogenous matrix formation.

The placental-umbilical unit in sickle cell disease pregnancy: A model for studying in vivo functional adjustments to hypoxia in humans

The placental-umbilical unit in sickle cell disease (SCD) pregnancy was used to explore hypoxia in vivo, an important factor in the pathophysiology of this disease. Gross examination and microscopic analysis of the placentas, taken immediately after delivery, indicate good concordance between maturity and term as controls, but higher frequency of vascular injuries such as excess syncytial knots, excess fibrin deposits, congestion and villous necroses. Unexpectedly, neither leukocyte recruitment nor alteration in extraplacental membrane was observed, suggesting the absence of inflammation. Additionally, interleukin (IL)-6 and IL-8 concentrations, measured by enzyme-linked immunosorbent assay (ELISA), were similar in the placental maternal blood from controls and SCD. There were also no significant differences found in IL-6 vein blood concentrations between controls and SCD, IL-8 being not detected. Immunostaining of umbilical vein endothelium in SCD pregnancies showed redistribution of PECAM-1 (CD31), von Willebrand factor (vWF), and P-selectin to the cell surface, controls exhibiting the classical pattern. Staining quantification indicated increases in vWF (+36.2%; P=.006) and vascular endothelial growth factor (VEGF) expression (+96.0%; P=.006) over control, but a reduction in endothelial nitric oxide synthase (eNOS) (-45.5%; P=.029). These results document, for the first time, direct functional adjustments in response to hypoxia in human in vivo. The mechanism for these changes has not been clearly established, but it may reflect increased tolerance to SCD hypoxic conditions and hypoxia in general.

[Squamous cell carcinoma on a leg ulcer in the West Indies]

INTRODUCTION

The epidemiology of carcinoma developing on a leg ulcer is poorly, although high incidence rates are reported in Africa.

PATIENTS AND METHODS

Retrospective study of cases reported in Guadeloupe, a tropical country with a large population from African descent and with high quality health care level.

RESULTS

Sixteen cases, mean age 71, were diagnosed over a 10-Year period in the only referral hospital. The annual incidence was an estimated 0.4/100,000. Preceding ulcers had a long course (mean of 27 Years) and had various causes. Social distress was the rule (14/16 patients). One third of the clearly differentiated (15/16) squamous cell-type tumors exhibited metastatic extension on presentation. At Year 3, the mortality rate was of 40 p. cent. The best survival rate (6 remissions/8 cases) was associated with primary limb amputation.

DISCUSSION

Malignant ulcers appeared more frequent in Guadeloupe than in the influent countries of the North, but with an instance 4-fold lower than in Africa. Like many other tropical diseases, socio-behavioral factors may play a major role.

Analyse en composantes principales de la grille AGGIR chez les patients âgés déments

AGGIR grid is the national standardized instrument determining aimed at the dependency of old people in France living in institutions as well as in the community. Attribution of the governmental financial assistance APA (Allocation Personnalisée d'Autonomie) depends essentially on the classification of frail old people in 6 degrees of dependency (GIR1 to GIR6). The aim of the present study was to test the reliability of this grid to evaluate the degree of dependency in demented elderly people. Mild, moderate or severe demented patients were included in the study (n= 120). A factorial validation of the A GGIR grid was performed by principal components analysis (PCA). This analysis showed a 5-factor solution: factor 1 named the property factor (27 percent of the variance), factor 2 named the dynamic factor (21 percent),factor 3 named the cognitive factor (20 percent), factor 4 named the external mobility factor (11 percent) and factor 5 named the communication factor (11 percent). The result showed that the AGGIR grid takes physical dependency more into account than psychological and behavioral dependency. This result suggests a need for readjustment of the AGGIR grid for demented patients by adding new variables taking into account psychosocial and behavioral disorders.

Factorial validation of the Severe Impairment Battery for patients with Alzheimer's disease. A pilot study

The Severe Impairment Battery (SIB) estimates the cognitive aptitudes and other skills of severely impaired dementia patients. The main objective of this pilot study was to clearly identify the number of factors present in the SIB and to analyze the relationships between the different cognitive domains explored by the SIB and loss of autonomy. We administered the SIB, the Mini Mental State Examination (MMSE) and two scales of dependency to 48 patients with Alzheimer's disease in its late stages. A factorial analysis (Principal Components Analysis) showed a 4-factor solution for the SIB: a cognitive factor, a praxis and visuospatial functions factor, the reactivity to external stimuli factor and the social aptitudes factor. A factorial analysis involving the dependency scales showed a cognitive factor, a dependency and constructional praxis factor, the reactivity to external stimuli factor and the social aptitudes factor. Reactivity to external stimuli and social aptitudes were not significantly correlated to cognitive aspects nor to dependency. The finding of dependency as a factor different from cognitive deterioration suggests that, in setting a treatment strategy for demented patients, attempts should be made to treat dependency in its own right. In addition, since reactivity to external stimuli and social aptitudes are not related to cognitive aspects nor to dependency, these functions should also be encouraged and stimulated.

Tissue reaction against a self-setting calcium phosphate cement set in bone or outside the organism

Calcium phosphate cements are able to set in situ when injected into bone tissue. We evaluated the tissue reaction occurring when a DCPD-based calcium phosphate cement was either set within the bone or implanted when already set. The samples were implanted in rabbit condyles and examined histologically after 8 and 16 weeks. The relative bone surface, the fibrous capsule around the implants and the implant section surface were measured. Solid material seemed to be better tolerated than paste implants. More bone was found at the solid implant contact whatever the implantation time and the solid material degraded much less rapidly. In conclusion, the physico-chemical modification of the biological environment occurring during setting increases the foreign body reaction against the material.

[Cysticercosis in Guadeloupe]

We report two cases of cysticercosis proved by histology, one in the brain, the other in the orbit. The first case was observed in a traveller, heavy smoker, serologically negative to cysticercosis in whom an isolated cerebral tumoral metastasis was suspected and resected. The lesion was centered by a typical cysticercus of Taenia solium. The second was a periorbital intramuscular nodule observed in a child who had never left our island. The fibroinflammatory nodule was centered by a cysticercus with a scolex without rostellum and without suckers. Its histological aspect led us to the diagnosis of cysticercosis. Three species of Taenia are discussed : T. solium, T. crassiceps and T. bovis. This case shows that the human transmission of the disease may exist in Guadeloupe.

[Cutaneo-mucous manifestations of dengue]

OBJECTIVES

To describe muco-cutaneous manifestations of dengue fever, assessing their incidence and histopathological aspects.

PATIENTS AND METHODS

During a dengue 2 epidemic, occurring in Guadeloupe in 1994, all patients admitted with a confirmed diagnostic of dengue fever were assessed for dermatological changes by 2 clinicians; 5 patients underwent skin biopsy with immuno-fluorescence staining.

RESULTS

Among 39 adult inpatients (Sex ratio 1.1, medium age 41 years) none presented a severe form of the disease, whereas 18/39 (46 p. 100) had some muco-cutaneous changes, associating rash (13 cases (33 p. 100)), mucous membranes involvement (7 cases (18 p. 100)), or minor haemorrhages (6 cases (15 p. 100)). The rash appeared macular, discrete, itching, troncular with peripheral extension, rather than maculo-papular (morbiliform) as usually described. Apart from cases which minor haemorrhagic changes, significatively associated with marked thrombocytopenia (medium 37 x 10(9)/1), dengue cases either with or without muco-cutaneous changes had similar clinical (duration, severity) or biological (neutro-lympho-thrombocytopenia, transaminases) features, and evolution. Histological changes appeared non specific (minor lymphocytic dermal vasculitis, non contributive immuno-fluorescence).

DISCUSSION

Clinical and histological features of the rash are unspecific and inconstant: they do not allow an easy and accurate diagnosis. Complete clinical, epidemiological (very recent travel in endemic areas) or biological data should be collected, and early virological or later serological confirmation is needed. As well as travel facilities are growing, the dengue area is extending: dengue fever should therefore be considered in every traveller with fever and rash.

Biomedical applications of maghemite ferrofluid

The use of cell-targeted ferrofluid in the characterization of modifications of cell membranes is reviewed. Maghemite ferrofluid was synthesized by the Massart method, complexed with dimercaptosuccinic acid (FF). Cell targeting by FF was developed by coupling FF to various biological effectors such as antibodies, lectins, etc, which enabled magnetic cell sorting. Modifications in erythrocyte membranes were studied using FF bound to recombinant human annexin V (AnxFF) which is very sensitive, compared to other Anx-based reagents, in the early detection of phosphatidylserine (PS) exposition on the outer leaflet of the plasma membrane. Thus PS exposition on mouse RBC was detected already after a 24-h storage at 4 degrees C and, transiently, 24 h after their infection by Plasmodium parasites, at which time the parasites are still confined to the liver, thus leading to the recruitment of young RBC and the accumulation of a species, intermediate between reticulocytes and erythrocytes, and the actual RBC target of plasmodial invasion. AnxFF revealed PS exposition on RBC from sickle cell anemia patients, following various inflammations and already after 20 days of human blood storage under blood bank conditions. Such a sensitive detection should be similar to that of macrophages which recognize exposed PS on cells and bring about the latter's elimination from the circulation. AnxFF binding determination was combined with that of cell electrophoretic mobility, glycerol resistance and filterability to characterize RBC membrane modifications in Alzheimer's disease patients which suggested a continuous damage and regeneration in RBC of these patients. A logistic analysis suggested that several three-parameter combinations could permit diagnosis of Alzheimer's disease with up to 95% accuracy. THP1 cells and macrophages, derived themselves by incubation with retinoic acid, were bound to FF and placed in a radio frequency alternating magnetic field. Magnetocytolysis was associated with FF attachment to the cells without damage to non-bound cells and without heating of the surrounding solution.

Increased total 7 alpha-hydroxy-dehydroepiandrosterone in serum of patients with Alzheimer's disease

Evidence has indicated that circulating adrenal steroid quantitites were significantly changed in patients with Alzheimer's disease (AD). Aside of 3 beta-sulfatation and 3 beta-acylations, levels of dehydroepiandrosterone (DHEA) result from production and metabolic transformation yields. 7 alpha-Hydroxylation of DHEA has been described in humans, and 7 alpha-hydroxy-DHEA may be responsible for the known antiglucocorticoid effects of DHEA. Using a negative ion fragmentometry method with gas chromatography/mass spectrometry on trifluoroacetate derivatives, we measured levels of free 7 alpha-hydroxy-DHEA as well as its sulfated conjugate and its fatty acid esters in serum of 10 female patients with AD and of 8 age-matched healthy control women. Free 7 alpha-hydroxy-DHEA levels in AD and controls were not significantly different (240.2 +/- 37.2 pg/ml and 206.8 +/- 21.6 pg/ml, respectively), but sulfate conjugate levels were significantly increased in AD (p = .01) (262 +/- 28.4 and 145.4 +/- 27.6, respectively) as well as fatty acid esters (p = .041) (65.7 +/- 6.9 and 40.7 +/- 9.2, respectively). These results indicated that the total 7 alpha-hydroxy-DHEA produced was significantly increased in AD (p = .024) and may contribute to the disease-related disturbances of DHEA production and metabolism.

Discrimination of facial identity and of emotions in Alzheimer's disease

OBJECTIVE

To investigate processing of human faces identity and of emotional expressions in patients with Alzheimer's Disease (AD).

BACKGROUND

Mechanisms responsible for discriminating facial identity may be dissociated from those involved in discriminating facial expressions. Patients with prosopagnosia often have preserved capacities for processing emotional facial expressions and occasionally, patients with focal lesions may recognize human faces without being able to recognize their facial expression. Such a dissociation has not been clearly shown in groups of AD patients.

METHODS

Thirty-one probable AD patients and 14 control subjects were administered tasks of discrimination of faces and of emotions.

RESULTS

AD patients were significantly impaired in discriminating facial identities and in naming and pointing to named emotions, but were comparable to controls in discriminating facial expressions of emotion. The deficits of facial discrimination and of identification of emotions were, on the whole, correlated with the MMS and Raven scores. Discrimination of emotions was not correlated to either test, suggesting that this ability is based on cognitive processes different from those underlying the MMS and the PM47.

CONCLUSIONS

This dissociation implies two separate systems, one dedicated to discrimination of facial identities and the other to discrimination of emotions. This is compatible with the modular organization of cognitive deficits in AD and may explain the well known experience that nonverbal communication often remains effective even in patients with severe dementia.

Membrane modifications of red blood cells in Alzheimer's disease

Red blood cells (RBC) from 24 Alzheimer's disease (AD) patients, 18 age- and sex-matched nondemented (ND) patients, hospitalized in the same facility for orthopedic problems, and 18 healthy volunteers aged 30-52 years were studied in order to gain insight into the nature of RBC membrane modifications in AD. Significant differences were found between RBC from AD and ND patients or young controls respectively for annexin V-binding (45.5 +/- 18.0% vs 27.1 +/- 14.7 and 2.7 +/- 1.9, p = .003), fraction of glycerol resistant cells (30.8 +/- 11.1% vs 19.6 +/- 6.4 and 10.2 +/- 3.1, p = .026), cell electrophoretic mobility in polymer (1.028 +/- 0.022 microns sec-1 V-1 cm vs 1.046 +/- 0.022 and 1.053 +/- 0.021, p = .02) and only limited significance for the filterability (1.46 +/- 0.12 msec vs 1.58 +/- 0.11 and 1.54 +/- 0.11, p = 0.1). A logistic analysis, using simultaneously several features as independent variables, suggested the combined use of annexinV- binding, glycerol resistance, and cell filterability which allowed the assignment of 95% of patients from this cohort to the right group. A prospective analysis of a larger cohort is required for the estimation of the diagnostic value of this test battery. In addition, the high level of annexin binding is characteristic of a disruption of the phospholipid asymmetry in aged or damaged cells, while the high glycerol resistance combined with low electrophoretic mobility an rigidity characterize young RBC, thus indicating an enhanced turnover of RBC in Alzheimer's disease.