A Phase 1/2 multicenter trial of DKN-01 as monotherapy or in combination with docetaxel for the treatment of metastatic castration-resistant prostate cancer (mCRPC)

BACKGROUND

Dickkopf-related protein 1 (DKK1) is a Wingless-related integrate site (Wnt) signaling modulator that is upregulated in prostate cancers (PCa) with low androgen receptor expression. DKN-01, an IgG4 that neutralizes DKK1, delays PCa growth in pre-clinical DKK1-expressing models. These data provided the rationale for a clinical trial testing DKN-01 in patients with metastatic castration-resistant PCa (mCRPC).

METHODS

This was an investigator-initiated parallel-arm phase 1/2 clinical trial testing DKN-01 alone (monotherapy) or in combination with docetaxel 75 mg/m2 (combination) for men with mCRPC who progressed on ≥1 AR signaling inhibitors. DKK1 status was determined by RNA in-situ expression. The primary endpoint of the phase 1 dose escalation cohorts was the determination of the recommended phase 2 dose (RP2D). The primary endpoint of the phase 2 expansion cohorts was objective response rate by iRECIST criteria in patients treated with the combination.

RESULTS

18 pts were enrolled into the study-10 patients in the monotherapy cohorts and 8 patients in the combination cohorts. No DLTs were observed and DKN-01 600 mg was determined as the RP2D. A best overall response of stable disease occurred in two out of seven (29%) evaluable patients in the monotherapy cohort. In the combination cohort, five out of seven (71%) evaluable patients had a partial response (PR). A median rPFS of 5.7 months was observed in the combination cohort. In the combination cohort, the median tumoral DKK1 expression H-score was 0.75 and the rPFS observed was similar between patients with DKK1 H-score ≥1 versus H-score = 0.

CONCLUSION

DKN-01 600 mg was well tolerated. DKK1 blockade has modest anti-tumor activity as a monotherapy for mCRPC. Anti-tumor activity was observed in the combination cohorts, but the response duration was limited. DKK1 expression in the majority of mCRPC is low and did not clearly correlate with anti-tumor activity of DKN-01 plus docetaxel.

Hematoxylin and Eosin staining of PhenoCycler® Fusion flow cell slides

Multiplexed Imaging technologies are powerful techniques that enable ultrahigh-plex spatial phenotyping of whole tissue sections at single cell spatial resolution. Co-Detection by Indexing (CODEX) multiplexing can detect up to 100 proteins using cyclic detection of DNA conjugated antibodies applied to tissue sections. However, it is necessary to correlate multiplexed fluorescent (mIF) spatial images with Hematoxylin and Eosin (H&E) stained sections post analysis. To effectively correlate mIF spatial images with H&E morphology, an (H&E) staining protocol was developed that is directly applied to the CODEX Fusion flow-cell slide after analysis allowing for direct H&E correlation and annotation with mIF images.

Antiviral innate immune memory in alveolar macrophages following SARS-CoV-2 infection

Pathogen encounter results in long-lasting epigenetic imprinting that shapes diseases caused by heterologous pathogens. The breadth of this innate immune memory is of particular interest in the context of respiratory pathogens with increased pandemic potential and wide-ranging impact on global health. Here, we investigated epigenetic imprinting across cell lineages in a disease relevant murine model of SARS-CoV-2 recovery. Past SARS-CoV-2 infection resulted in increased chromatin accessibility of type I interferon (IFN-I) related transcription factors in airway-resident macrophages. Mechanistically, establishment of this innate immune memory required viral pattern recognition and canonical IFN-I signaling and augmented secondary antiviral responses. Past SARS-CoV-2 infection ameliorated disease caused by the heterologous respiratory pathogen influenza A virus. Insights into innate immune memory and how it affects subsequent infections with heterologous pathogens to influence disease pathology could facilitate the development of broadly effective therapeutic strategies.

Inflammation in the tumor-adjacent lung as a predictor of clinical outcome in lung adenocarcinoma

Approximately 30% of early-stage lung adenocarcinoma patients present with disease progression after successful surgical resection. Despite efforts of mapping the genetic landscape, there has been limited success in discovering predictive biomarkers of disease outcomes. Here we performed a systematic multi-omic assessment of 143 tumors and matched tumor-adjacent, histologically-normal lung tissue with long-term patient follow-up. Through histologic, mutational, and transcriptomic profiling of tumor and adjacent-normal tissue, we identified an inflammatory gene signature in tumor-adjacent tissue as the strongest clinical predictor of disease progression. Single-cell transcriptomic analysis demonstrated the progression-associated inflammatory signature was expressed in both immune and non-immune cells, and cell type-specific profiling in monocytes further improved outcome predictions. Additional analyses of tumor-adjacent transcriptomic data from The Cancer Genome Atlas validated the association of the inflammatory signature with worse outcomes across cancers. Collectively, our study suggests that molecular profiling of tumor-adjacent tissue can identify patients at high risk for disease progression.

Automated and robust extraction of genomic DNA from various leftover blood samples

With the development of genomic technologies, the isolation of genomic DNA (gDNA) from clinical samples is increasingly required for clinical diagnostics and research studies. In this study, we explored the potential of utilizing various leftover blood samples obtained from routine clinical tests as a viable source of gDNA. Using an automated method with optimized pre-treatments, we obtained gDNA from seven types of clinical leftover blood, with average yields of gDNA ranging from 3.11 ± 0.45 to 22.45 ± 4.83 μg. Additionally, we investigated the impact of storage conditions on gDNA recovery, resulting in yields of 8.62-68.08 μg when extracting gDNA from EDTA leftover blood samples stored at 4 °C for up to 13 weeks or -80 °C for up to 78 weeks. Furthermore, we successfully obtained sequenceable gDNA from both Serum Separator Tube and EDTA Tube using a 96-well format extraction, with yields ranging from 0.61 to 71.29 μg and 3.94-215.98 μg, respectively. Our findings demonstrate the feasibility of using automated high-throughput platforms for gDNA extraction from various clinical leftover blood samples with the proper pre-treatments.

Persistent hepatitis B virus and HIV coinfections in dually humanized mice engrafted with human liver and immune system

Chronic hepatitis B (CHB), caused by hepatitis B virus (HBV), remains a major medical problem. HBV has a high propensity for progressing to chronicity and can result in severe liver disease, including fibrosis, cirrhosis, and hepatocellular carcinoma. CHB patients frequently present with viral coinfection, including human immunodeficiency virus type (HIV) and hepatitis delta virus. About 10% of chronic HIV carriers are also persistently infected with HBV, which can result in more exacerbated liver disease. Mechanistic studies of HBV-induced immune responses and pathogenesis, which could be significantly influenced by HIV infection, have been hampered by the scarcity of immunocompetent animal models. Here, we demonstrate that humanized mice dually engrafted with components of a human immune system and a human liver supported HBV infection, which was partially controlled by human immune cells, as evidenced by lower levels of serum viremia and HBV replication intermediates in the liver. HBV infection resulted in priming and expansion of human HLA-restricted CD8+ T cells, which acquired an activated phenotype. Notably, our dually humanized mice support persistent coinfections with HBV and HIV, which opens opportunities for analyzing immune dysregulation during HBV and HIV coinfection, and preclinical testing of novel immunotherapeutics.

Spatial transcriptomics stratifies psoriatic disease severity by emergent cellular ecosystems

Whereas the cellular and molecular features of human inflammatory skin diseases are well characterized, their tissue context and systemic impact remain poorly understood. We thus profiled human psoriasis (PsO) as a prototypic immune-mediated condition with a high predilection for extracutaneous involvement. Spatial transcriptomics (ST) analyses of 25 healthy, active lesion, and clinically uninvolved skin biopsies and integration with public single-cell transcriptomics data revealed marked differences in immune microniches between healthy and inflamed skin. Tissue-scale cartography further identified core disease features across all active lesions, including the emergence of an inflamed suprabasal epidermal state and the presence of B lymphocytes in lesional skin. Both lesional and distal nonlesional samples were stratified by skin disease severity and not by the presence of systemic disease. This segregation was driven by macrophage-, fibroblast-, and lymphatic-enriched spatial regions with gene signatures associated with metabolic dysfunction. Together, these findings suggest that mild and severe forms of PsO have distinct molecular features and that severe PsO may profoundly alter the cellular and metabolic composition of distal unaffected skin sites. In addition, our study provides a valuable resource for the research community to study spatial gene organization of healthy and inflamed human skin.

Histopathology of the Mitral Valve Residual Leaflet in Obstructive Hypertrophic Cardiomyopathy

BACKGROUND

Mitral valve (MV) elongation is a primary hypertrophic cardiomyopathy (HCM) phenotype and contributes to obstruction. The residual MV leaflet that protrudes past the coaptation point is especially susceptible to flow-drag and systolic anterior motion. Histopathological features of MVs in obstructive hypertrophic cardiomyopathy (OHCM), and of residual leaflets specifically, are unknown.

OBJECTIVES

The purpose of this study was to characterize gross, structural, and cellular histopathologic features of MV residual leaflets in OHCM. On a cellular-level, we assessed for developmental dysregulation of epicardium-derived cell (EPDC) differentiation, adaptive endocardial-to-mesenchymal transition and valvular interstitial cell proliferation, and genetically-driven persistence of cardiomyocytes in the valve.

METHODS

Structural and immunohistochemical staining were performed on 22 residual leaflets excised as ancillary procedures during myectomy, and compared with 11 control leaflets from deceased patients with normal hearts. Structural components were assessed with hematoxylin and eosin, trichrome, and elastic stains. We stained for EPDCs, EPDC paracrine signaling, valvular interstitial cells, endocardial-to-mesenchymal transition, and cardiomyocytes.

RESULTS

The residual leaflet was always at A2 segment and attached by slack, elongated and curlicued, myxoid chords. MV residual leaflets in OHCM were structurally disorganized, with expanded spongiosa and increased, fragmented elastic fibers compared with control leading edges. The internal collagenous fibrosa was attenuated and there was collagenous tissue overlying valve surfaces in HCM, with an overall trend toward decreased leaflet thickness (1.09 vs 1.47 mm, P = 0.08). No markers of primary cellular processes were identified.

CONCLUSIONS

MV residual leaflets in HCM were characterized by histologic findings that were likely secondary to chronic hemodynamic stress and may further increase susceptibility to systolic anterior motion.

Human hepatocyte PNPLA3-148M exacerbates rapid non-alcoholic fatty liver disease development in chimeric mice

Advanced non-alcoholic fatty liver disease (NAFLD) is a rapidly emerging global health problem associated with pre-disposing genetic polymorphisms, most strikingly an isoleucine to methionine substitution in patatin-like phospholipase domain-containing protein 3 (PNPLA3-I148M). Here, we study how human hepatocytes with PNPLA3 148I and 148M variants engrafted in the livers of broadly immunodeficient chimeric mice respond to hypercaloric diets. As early as four weeks, mice developed dyslipidemia, impaired glucose tolerance, and steatosis with ballooning degeneration selectively in the human graft, followed by pericellular fibrosis after eight weeks of hypercaloric feeding. Hepatocytes with the PNPLA3-148M variant, either from a homozygous 148M donor or overexpressed in a 148I donor background, developed microvesicular and severe steatosis with frequent ballooning degeneration, resulting in more active steatohepatitis than 148I hepatocytes. We conclude that PNPLA3-148M in human hepatocytes exacerbates NAFLD. These models will facilitate mechanistic studies into human genetic variant contributions to advanced fatty liver diseases.

A phase 1/2 multicenter investigator-initiated trial of DKN-01 as monotherapy or in combination with docetaxel for the treatment of metastatic castration-resistant prostate cancer (mCRPC)

5048

Background: Dickkopf-1 (DKK1) is a secreted Wnt signaling modulator that is upregulated in prostate cancers with low androgen receptor (AR) expression and co-occurring mutations in Wnt signaling family genes. DKN-01, a potent humanized monoclonal antibody (IgG4) with neutralizing activity against DKK1, delays prostate cancer growth in pre-clinical DKK1-expressing models in an NK cell dependent manner. These data provided the rationale for a prospective clinical trial testing DKN-01 in patients with mCRPC and elevated DKK1. Here, we report the safety and efficacy results of the phase 1 dose escalation cohorts. Methods: This is an investigator-initiated parallel-arm non-randomized phase 1/2 clinical trial testing DKN-01 alone or in combination with docetaxel 75 mg/m2 for men with mCRPC who progressed on ≥1 AR signaling inhibitor. Eligible patients who had progressed on or were intolerant of docetaxel were assigned to the monotherapy cohort whereas taxane-naïve patients were assigned to the DKN-01 plus docetaxel combination cohort. DKK1 status was determined by RNA in-situ expression. The primary endpoint of the phase 1 dose escalation cohorts was safety, characterized by dose-limiting toxicity (DLT). A secondary endpoint of the study was to correlate anti-tumor activity, DKK1 expression (cutoff H-score ≥ 1), and clinical evidence of aggressive variant prostate cancer (AVPC). Results: 13 pts were enrolled in the completed phase 1 portion of this study – 7 patients in the monotherapy cohort and 6 patients in the combination cohort. No DLTs were observed at DKN-01 300mg or 600mg dose levels as monotherapy or in combination with docetaxel. No treatment-related serious adverse events occurred in either cohort. A best overall response of stable disease occurred in 2 out of 7 patients in the monotherapy cohort. In the combination cohort, all 5 evaluable patients had a partial response (PR) – 3 confirmed and 2 unconfirmed. All evaluable combination patients had ≥ 50% reduction in either PSA or CEA. Confirmed PRs in the combination cohort were observed in both DKK1 low (DKK1 H-score < 1) and high expressing tumors (H-score ≥1), including in 2 out of 3 patients with AVPC. Conclusions: DKN-01 600mg was well tolerated and selected as the recommended phase 2 dose as monotherapy and in combination with docetaxel. DKN-01 in combination with docetaxel showed promising clinical activity in prostate cancers regardless of DKK1 expression and was particularly promising in patients with AVPC. Further accrual into the phase 2 portion of this study is ongoing alongside preclinical and correlative studies aiming to investigate the mechanism of action of this combination therapeutic strategy. Clinical trial information: NCT03837353.

Membrane attack complex (MAC) deposition in renal tubules is associated with interstitial fibrosis and tubular atrophy: a pilot study

INTRODUCTION

Treatment failures for lupus nephritis (LN) are high with 10%-30% of patients progressing to end-stage renal disease (ESRD) within 10 years. Interstitial fibrosis/tubular atrophy (IFTA) is a predictor of progression to ESRD. Prior studies suggest that tubulointerstitial injury secondary to proteinuria in LN is mediated by complement activation in the tubules, specifically through the membrane attack complex (MAC). This study aimed to investigate the associations between tubular MAC deposition with IFTA and proteinuria.

METHODS

In this cross-sectional study, LN kidney biopsies were assessed for MAC deposition by staining for Complement C9, a component of the MAC. Chromogenic immunohistochemistry was performed on paraffin-embedded human renal biopsy sections using unconjugated, murine anti-human Complement C9 (Hycult Biotech, clone X197). Tubular C9 staining intensity was analysed as present versus absent. IFTA was defined as minimal (<10%), mild (10%-24%), moderate (25%-50%) and severe (>50%).

RESULTS

Renal biopsies from 30 patients with LN were studied. There were 24 (80%) female sex, mean age (SD) was 33 (12) years old and 23 (77%) had pure/mixed proliferative LN. Tubular C9 staining was present in 7 (23%) biopsies. 27 patients had minimal-to-mild IFTA and 3 patients had moderate IFTA. Among the C9 + patients, 3 (43%) had moderate IFTA as compared with none in the C9- group, p=0.009. C9 + patients had higher median (IQR) proteinuria as compared with C9- patients: 6.2 g (3.3-13.1) vs 2.4 g (1.3-4.6), p=0.001 at the time of biopsy. There was no difference in estimated glomerular filtration rate (eGFR) between the C9 + and C9- groups.

CONCLUSION

This study demonstrated that tubular MAC deposition is associated with higher degree of IFTA and proteinuria, which are predictors of progression to ESRD. These results suggest that tubular MAC deposition may be useful in classification of LN. Understanding the role of complement in tubulointerstitial injury will also identify new avenues for LN treatment.

Somatic Focal Copy Number Gains of Noncoding Regions of Receptor Tyrosine Kinase Genes in Treatment-Resistant Epilepsy

Epilepsy is a heterogenous group of disorders defined by recurrent seizure activity due to abnormal synchronized activity of neurons. A growing number of epilepsy cases are believed to be caused by genetic factors and copy number variants (CNV) contribute to up to 5% of epilepsy cases. However, CNVs in epilepsy are usually large deletions or duplications involving multiple neurodevelopmental genes. In patients who underwent seizure focus resection for treatment-resistant epilepsy, whole genome DNA methylation profiling identified 3 main clusters of which one showed strong association with receptor tyrosine kinase (RTK) genes. We identified focal copy number gains involving epidermal growth factor receptor (EGFR) and PDGFRA loci. The dysplastic neurons of cases with amplifications showed marked overexpression of EGFR and PDGFRA, while glial and endothelial cells were negative. Targeted sequencing of regulatory regions and DNA methylation analysis revealed that only enhancer regions of EGFR and gene promoter of PDGFRA were amplified, while coding regions did not show copy number abnormalities or somatic mutations. Somatic focal copy number gains of noncoding regulatory represent a previously unrecognized genetic driver in epilepsy and a mechanism of abnormal activation of RTK genes. Upregulated RTKs provide a potential avenue for therapy in seizure disorders.

Validation of PD-L1 clone 22C3 immunohistochemical stain on two Ventana DISCOVERY autostainer models: detailed protocols, test performance characteristics, and interobserver reliability analyses

Immunohistochemical (IHC) stain for PD-L1 as a biomarker for immunotherapy is recommended in non-small cell lung cancer (NSCLC). Under the FDA, the selection of patients for pembrolizumab requires companion diagnostic testing using the Dako Agilent PD-L1 IHC 22C3 pharmDx kit performed on the Dako Autostainer Link 48 platform. However, because it is not widely available, there is need for cross-platform validation. Existing studies provide incomplete protocol detail. In our study, 73 lung tumors were stained using the FDA-approved test ('gold standard'). The same blocks were stained using two different models of the Ventana DISCOVERY platform (ULTRA, n = 73 and XT, n = 70) using different parameters, and interpreted by three pathologists. The ULTRA group met College of American Pathologists (CAP) validation criteria (concordance 91.8%) while the XT group did not (concordance 67.1%). Using tumor proportion score (TPS) ≥1% and TPS ≥50% as cut-offs, the ULTRA protocol had higher sensitivity (97.8% and 91.7%) than XT (73.3% and 60.9%) and similar specificity (ULTRA 88.9% and 100%, XT 88% and 100%). Discordance between ULTRA and XT was 27%, and in all these cases ULTRA was concordant with gold standard. Interobserver reliability was substantial for ULTRA and almost perfect for XT, providing evidence that staining rather than observer variability accounts for XT's inferior performance. Cross-validation of the clinically used 22C3 anti PD-L1 antibody test with substantial interobserver agreement is possible on the commonly used the Ventana DISCOVERY ULTRA automated instrument, while the validation failed on the XT. Cautious attention to detail must be paid when choosing cross-validation parameters.

Keratin 19 and mesenchymal markers for evaluation of epithelial-mesenchymal transition and stem cell niche components in primary biliary cholangitis by sequential elution-stripping multiplex immunohistochemistry

Multiplexed immunohistochemical techniques give insight into contextual cellular relationships by offering the ability to collect cell-specific data with spatial information from formalin-fixed, paraffin-embedded tissue sections. We established an automated sequential elution-stripping multiplex immunohistochemical assay to address two controversial scientific questions in the field of hepatopathology: 1) whether epithelial-to-mesenchymal transition or mesenchymal-to-epithelial transition occurs during liver injury and repair of a chronic liver disease and 2) if there is a stromal:epithelial relationship along the canals of Hering that would support the concept of this biliary structure being a stem/progenitor cell niche. Our 4-plex assay includes both epithelial and mesenchymal clinical immunohistochemical markers and was performed on clinical human liver specimens in patients with primary biliary cholangitis. The assay demonstrated that in each specimen, co-expression of epithelial and mesenchymal markers was observed in extraportal cholangiocytes. In regard to possible mesenchymal components in a stem cell niche, 82.3% ± 5.5% of extraportal cholangiocytes were intimately associated with a vimentin-positive cell. Co-expression of epithelial and mesenchymal markers by extraportal cholangiocytes is evidence for epithelial to mesenchymal transition in primary biliary cholangitis. Vimentin-positive stromal cells are frequently juxtaposed to extraportal cholangiocytes, supporting an epithelial:mesenchymal relationship within the hepatobiliary stem cell niche. Our automated sequential elution-stripping multiplex immunohistochemical assay is a cost-effective multiplexing technique that can be readily applied to a small series of clinical pathology samples in order to answer scientific questions involving cell:cell relationships and cellular antibody expression.

Experimental Variables that Affect Human Hepatocyte AAV Transduction in Liver Chimeric Mice

Adeno-associated virus (AAV) vector serotypes vary in their ability to transduce hepatocytes from different species. Chimeric mouse models harboring human hepatocytes have shown translational promise for liver-directed gene therapies. However, many variables that influence human hepatocyte transduction and transgene expression in such models remain poorly defined. Here, we aimed to test whether three experimental conditions influence AAV transgene expression in immunodeficient, fumaryl-acetoactetate-hydrolase-deficient (Fah -/-) chimeric mice repopulated with primary human hepatocytes. We examined the effects of the murine liver injury cycle, human donor variability, and vector doses on hepatocyte transduction with various AAV serotypes expressing a green fluorescent protein (GFP). We determined that the timing of AAV vector challenge in the liver injury cycle resulted in up to 7-fold differences in the percentage of GFP expressing human hepatocytes. The GFP+ hepatocyte frequency varied 7-fold between human donors without, however, changing the relative transduction efficiency between serotypes for an individual donor. There was also a clear relationship between AAV vector doses and human hepatocyte transduction and transgene expression. We conclude that several experimental variables substantially affect human hepatocyte transduction in the Fah -/- chimera model, attention to which may improve reproducibility between findings from different laboratories.

The diagnostic utility of EZH2 H-score and Ki-67 index in non-invasive breast apocrine lesions

In diagnostic breast pathology, there is no reliable applicable immunostain to help discern atypical and in situ apocrine lesions from benign apocrine tissue. At present, the diagnosis of non-invasive apocrine lesions remains challenging with current diagnoses rendered based on discrete morphologic characteristics on conventional hematoxylin and eosin staining. Interobserver variability is significant even among subspecialists partly due to lack of adjuvant diagnostic immunohistochemical stains. Herein, we set to elucidate the potential utility of EZH2 and Ki-67 immunostains as tangible tools in non-invasive apocrine proliferations. A cohort of apocrine breast lesions [Benign apocrine hyperplasia (BAH), n = 10; Atypical apocrine hyperplasia (AAH), n = 16; Apocrine ductal carcinoma in situ (ADCIS), n = 12] were subjected to EZH2 immunostaining and analyzed via H-scoring of nuclear expression. Mean H-scores for EZH2 progressively increased from BAH (23.5), to AAH (47.4) and ADCIS (196.4), and showed a significant difference utilizing the Kruskal-Wallis test (p < 0.0001). Further interrogation of Ki-67 demonstrated incremental expression from BAH to AAH and ADCIS at 1.6 %, 4.7 % and 24.7 %, respectively (p < 0.0001, Kruskal-Wallis test), suggesting an association with increased proliferation. Our results demonstrate that a combination of EZH2 and Ki-67 immunostaining may be employed in differentiating among challenging apocrine breast lesions and suggest a putative diagnostic utility for EZH2 and Ki-67 in non-invasive apocrine breast lesions.

Expression profiling of the adhesion G protein-coupled receptor GPR133 (ADGRD1) in glioma subtypes

Background

Glioma is a family of primary brain malignancies with limited treatment options and in need of novel therapies. We previously demonstrated that the adhesion G protein-coupled receptor GPR133 (ADGRD1) is necessary for tumor growth in adult glioblastoma, the most advanced malignancy within the glioma family. However, the expression pattern of GPR133 in other types of adult glioma is unknown.

Methods

We used immunohistochemistry in tumor specimens and non-neoplastic cadaveric brain tissue to profile GPR133 expression in adult gliomas.

Results

We show that GPR133 expression increases as a function of WHO grade and peaks in glioblastoma, where all tumors ubiquitously express it. Importantly, GPR133 is expressed within the tumor bulk, as well as in the brain-infiltrating tumor margin. Furthermore, GPR133 is expressed in both isocitrate dehydrogenase (IDH) wild-type and mutant gliomas, albeit at higher levels in IDH wild-type tumors.

Conclusion

The fact that GPR133 is absent from non-neoplastic brain tissue but de novo expressed in glioma suggests that it may be exploited therapeutically.

Preclinical assessment of antiviral combination therapy in a genetically humanized mouse model for hepatitis delta virus infection

Chronic delta hepatitis, caused by hepatitis delta virus (HDV), is the most severe form of viral hepatitis, affecting at least 20 million hepatitis B virus (HBV)-infected patients worldwide. HDV/HBV co- or superinfections are major drivers for hepatocarcinogenesis. Antiviral treatments exist only for HBV and can only suppress but not cure infection. Development of more effective therapies has been impeded by the scarcity of suitable small-animal models. We created a transgenic (tg) mouse model for HDV expressing the functional receptor for HBV and HDV, the human sodium taurocholate cotransporting peptide NTCP. Both HBV and HDV entered hepatocytes in these mice in a glycoprotein-dependent manner, but one or more postentry blocks prevented HBV replication. In contrast, HDV persistently infected hNTCP tg mice coexpressing the HBV envelope, consistent with HDV dependency on the HBV surface antigen (HBsAg) for packaging and spread. In immunocompromised mice lacking functional B, T, and natural killer cells, viremia lasted at least 80 days but resolved within 14 days in immunocompetent animals, demonstrating that lymphocytes are critical for controlling HDV infection. Although acute HDV infection did not cause overt liver damage in this model, cell-intrinsic and cellular innate immune responses were induced. We further demonstrated that single and dual treatment with myrcludex B and lonafarnib efficiently suppressed viremia but failed to cure HDV infection at the doses tested. This small-animal model with inheritable susceptibility to HDV opens opportunities for studying viral pathogenesis and immune responses and for testing novel HDV therapeutics.

Transcriptomic profiles conducive to immune-mediated tumor rejection in human breast cancer skin metastases treated with Imiquimod

Imiquimod is a topical toll-like-receptor-7 agonist currently used for treating basal cell carcinoma. Recently, imiquimod has demonstrated tumor regression in melanoma and breast cancer skin metastases. However, the molecular perturbations induced by imiquimod in breast cancer metastases have not been previously characterized. Here, we describe transcriptomic profiles associated with responsiveness to imiquimod in breast cancer skin metastases. Baseline and post-treatment tumor samples from patients treated with imiquimod in a clinical trial were profiled using Nanostring technology. Through an integrative analytic pipeline, we showed that tumors from patients who achieved a durable clinical response displayed a permissive microenvironment, substantiated by the upregulation of transcripts encoding for molecules involved in leukocyte adhesion and migration, cytotoxic functions, and antigen presentation. In responding patients, Imiquimod triggered a strong T-helper-1 (Th-1)/cytotoxic immune response, characterized by the coordinated upregulation of Th-1 chemokines, migration of Th-1 and cytotoxic T cells into the tumor, and activation of immune-effector functions, ultimately mediating tumor destruction. In conclusion, we have shown that topical imiquimod can induce a robust immune response in breast cancer metastases, and this response is more likely to occur in tumors with a pre-activated microenvironment. In this setting, imiquimod could be utilized in combination with other targeted immunotherapies to increase therapeutic efficacy.

Single cell analysis of urothelial carcinoma (UC) liver metastases identifies epithelial-mesenchymal transition (EMT) as a potential mechanism of resistance to immunotherapy

e16018

Background: UC liver metastases are associated with a low response rate to immune checkpoint blockade (ICB) and short survival. We sought to identify tumor specific factors promoting resistance to ICB. Methods: DEPArray is a dielectrophoresis based cell sorting platform for isolating immunohistochemically-defined cell populations from formalin-fixed paraffin-embedded (FFPE) tissue. Available FFPE tissue blocks of mUC liver metastases from patients (pts) treated with ICB were selected for analysis. Following histologic evaluation, tissue blocks were digested to yield cellular suspensions for immunophenotypic DEPArray sorting by keratin (K) and vimentin (V) to identify carcinoma cells and stromal cells, respectively. Cell pools were further analyzed for recurrent mutations and copy number alterations by a targeted OncoSeek panel and by MiSeq. Results: 12 unique patient samples were profiled. Median age was 73 (range 65-89), 11/12 male, 7 (58%) were platinum-refractory, and 4 (33%) received only ICB. 7 (58%) biopsies were obtained prior to initiation of ICB (1PR, 1SD, 5PD). Routine H&E sections generally revealed tumors completely devoid of immune cells, but admixed with atypical mesenchymal cells ranging from 5% to 60% of cellular composition. DEPArray sorting by K and V identified three discrete cell populations: K+/V- carcinoma cells, K-/V+ stromal cells, and K+/V+ cells that exhibited mesenchymal morphology. Of 8 samples with adequate cell counts (range 75-154 cells), next-generation sequencing (NGS) identified that K+/V- carcinoma cells and K+/V+ double positive cells shared unique somatic alterations in 7 (88%) pts, including point mutations in FGFR3, ERBB2, FBXW7, PIK3CA, FLT3 and STK11, and amplification of CDK4. In one liver responder to ICB, V+ stromal cells carried a putative germline TP53 R248W mutation. Conclusions: Archival FFPE tissue from mUC liver metastases can be digitally sorted by DEPArray to yield pools of ~100 cells suitable for NGS. UC liver metastases exhibit a population of K+/V+ cells with clonal somatic alterations suggestive of an EMT cancer cell phenotype that may be playing a role in ICB resistance.

Cell Surface Notch Ligand DLL3 is a Therapeutic Target in Isocitrate Dehydrogenase-mutant Glioma

PURPOSE

Isocitrate dehydrogenase (IDH)-mutant glioma is a distinct glioma molecular subtype for which no effective molecularly directed therapy exists. Low-grade gliomas, which are 80%-90% IDH-mutant, have high RNA levels of the cell surface Notch ligand DLL3. We sought to determine DLL3 expression by IHC in glioma molecular subtypes and the potential efficacy of an anti-DLL3 antibody-drug conjugate (ADC), rovalpituzumab tesirine (Rova-T), in IDH-mutant glioma.

EXPERIMENTAL DESIGN

We evaluated DLL3 expression by RNA using TCGA data and by IHC in a discovery set of 63 gliomas and 20 nontumor brain tissues and a validation set of 62 known IDH wild-type and mutant gliomas using a monoclonal anti-DLL3 antibody. Genotype was determined using a DNA methylation array classifier or by sequencing. The effect of Rova-T on patient-derived endogenous IDH-mutant glioma tumorspheres was determined by cell viability assay.

RESULTS

Compared to IDH wild-type glioblastoma, IDH-mutant gliomas have significantly higher DLL3 RNA (P < 1 × 10^-15) and protein by IHC (P = 0.0014 and P < 4.3 × 10^-6 in the discovery and validation set, respectively). DLL3 immunostaining was intense and homogeneous in IDH-mutant gliomas, retained in all recurrent tumors, and detected in only 1 of 20 nontumor brains. Patient-derived IDH-mutant glioma tumorspheres overexpressed DLL3 and were potently sensitive to Rova-T in an antigen-dependent manner.

CONCLUSIONS

DLL3 is selectively and homogeneously expressed in IDH-mutant gliomas and can be targeted with Rova-T in patient-derived IDH-mutant glioma tumorspheres. Our findings are potentially immediately translatable and have implications for therapeutic strategies that exploit cell surface tumor-associated antigens.

Chibby is a weak regulator of β-catenin activity in gastric epithelium

The canonical Wnt-β-catenin pathway is important in normal development. Mutations in β-catenin or proteins involved with regulating its phosphorylation or localization result in its nuclear accumulation where it activates its target genes and stimulates cell proliferation. This pathway is dysregulated in many different types of cancer, including gastric cancer (GC). Chibby (Cby) is a 14-kDa protein that inhibits β-catenin localization to the nucleus and represses β-catenin-induced transcriptional activity. In the current study, we examined the expression and function of Cby in normal and cancerous human gastric tissue. Reverse-transcription polymerase chain reaction and immunohistochemistry revealed that Cby is expressed in human stomach and localized to glandular elements. Immunohistochemical staining intensity of Cby was decreased in GC tissue when compared with normal gastric epithelium. In AGS cells, a human gastric carcinoma cell line, Cby expression was low. Stable AGS cell transfectants overexpressing Cby were prepared. Cby overexpression did not affect proliferation rates or β-catenin levels. However, confocal microscopy and subcellular fractionation studies revealed that Cby overexpression resulted in a small decrease in nuclear β-catenin. Moreover, Cby overexpression caused a molecular weight shift in nuclear β-catenin and resulted in decreased β-catenin signaling in AGS cells as measured by the TopFlash assay. However, Cby overexpression did not affect c-Myc protein levels. To conclude, Cby expression was decreased in GC samples and Cby expression altered β-catenin localization in cultured GC cells. However, Cby did not affect cell proliferation rates or β-catenin-induced protein expression. Cby may be involved in the early events in the pathogenesis of GC.

Low-Grade Astrocytoma Mutations in IDH1, P53, and ATRX Cooperate to Block Differentiation of Human Neural Stem Cells via Repression of SOX2

Low-grade astrocytomas (LGAs) carry neomorphic mutations in isocitrate dehydrogenase (IDH) concurrently with P53 and ATRX loss. To model LGA formation, we introduced R132H IDH1, P53 shRNA, and ATRX shRNA into human neural stem cells (NSCs). These oncogenic hits blocked NSC differentiation, increased invasiveness in vivo, and led to a DNA methylation and transcriptional profile resembling IDH1 mutant human LGAs. The differentiation block was caused by transcriptional silencing of the transcription factor SOX2 secondary to disassociation of its promoter from a putative enhancer. This occurred because of reduced binding of the chromatin organizer CTCF to its DNA motifs and disrupted chromatin looping. Our human model of IDH mutant LGA formation implicates impaired NSC differentiation because of repression of SOX2 as an early driver of gliomagenesis.

Targeting Poxvirus Decapping Enzymes and mRNA Decay to Generate an Effective Oncolytic Virus

Through the action of two virus-encoded decapping enzymes (D9 and D10) that remove protective caps from mRNA 5′-termini, Vaccinia virus (VACV) accelerates mRNA decay and limits activation of host defenses. D9- or D10-deficient VACV are markedly attenuated in mice and fail to counter cellular double-stranded RNA-responsive innate immune effectors, including PKR. Here, we capitalize upon this phenotype and demonstrate that VACV deficient in either decapping enzyme are effective oncolytic viruses. Significantly, D9- or D10-deficient VACV displayed anti-tumor activity against syngeneic mouse tumors of different genetic backgrounds and human hepatocellular carcinoma xenografts. Furthermore, D9- and D10-deficient VACV hyperactivated the host anti-viral enzyme PKR in non-tumorigenic cells compared to wild-type virus. This establishes a new genetic platform for oncolytic VACV development that is deficient for a major pathogenesis determinant while retaining viral genes that support robust productive replication like those required for nucleotide metabolism. It further demonstrates how VACV mutants unable to execute a fundamental step in virus-induced mRNA decay can be unexpectedly translated into a powerful anti-tumor therapy.

Mouse models of acute and chronic hepacivirus infection

An estimated 71 million people worldwide are infected with hepatitis C virus (HCV). The lack of small-animal models has impeded studies of antiviral immune mechanisms. Here we show that an HCV-related hepacivirus discovered in Norway rats can establish high-titer hepatotropic infections in laboratory mice with immunological features resembling those seen in human viral hepatitis. Whereas immune-compromised mice developed persistent infection, immune-competent mice cleared the virus within 3 to 5 weeks. Acute clearance was T cell dependent and associated with liver injury. Transient depletion of CD4⁺ T cells before infection resulted in chronic infection, characterized by high levels of intrahepatic regulatory T cells and expression of inhibitory molecules on intrahepatic CD8⁺ T cells. Natural killer cells controlled early infection but were not essential for viral clearance. This model may provide mechanistic insights into hepatic antiviral immunity, a prerequisite for the development of HCV vaccines.

Identification of differentially expressed genes associated with clinical response after treatment of breast cancer skin metastases with imiquimod

e12541

Background: Imiquimod, a Toll-like receptor 7 agonist, activates innate immunity and has a response rate of 20% in breast cancer skin metastases. Tumor regression is associated with increased tumor infiltrating lymphocytes and increased Th1 cytokines in tumor supernatant, however gene expression changes are unknown. This is the first report of gene expression changes induced by imiquimod treatment in breast cancer skin metastases. Methods: FFPE-extracted mRNA from 8 patients pre and post 8 weeks of imiquimod treatment was analyzed using Nanostring PanCancer Immune Profiling Panel. Gene expression and pathway analysis was conducted with nSolver 3.0 with clinical response as outcome, controlling for HER2 ER/PR status, with 5% significance level used. Results: In all patients, imiquimod was associated with upregulation of genes in innate immunity such as TLR7, IL-1, T-cell, B-cell, and NK related genes. Three patients had a clinical response after imiquimod. Forty-two differentially expressed genes were identified in responders vs. non-responders after imiquimod. Reponders had up-regulation of T cell (CD2, SPN), NK cell (KLRC2), B cell (CD48), lymphocyte (LY96), and IL-2 (IL2RG) related genes. The top upregulated pathways were cytotoxicity, NK cell function, and antigen processing. Pre-treatment, the responders had upregulation of TNF and IL-17 related genes (TNFRSF10B, IL17RA) compared to non-responders. Comparing pre-treatment to post-treatment, Imiquimod was associated with mRNA expression changes in 72 genes in responders vs non responders. The top upregulated genes involved activation of lymphocytes (SH2D1A), NK cells (KLRC2), DCs (CLEC4C), several chemokines, IL7R and immune regulators PLD1 and IRF5. Conclusions: Clinical response to Imiquimod treatment of breast cancer skin metastases is associated with upregulation of genes in innate immunity suggestive of an anti-tumor immune response. Inhibition of negative feedback by addition of PLD1 inhibitors may enhance treatment response. Understanding the genetic signature of imiquimod can enhance prediction of response and inform possible combination therapies in the future.

Arrested Development: Infantile Hemangioma and the Stem Cell Teratogenic Hypothesis

BACKGROUND

Early-life programming is defined by the adaptive changes made by the fetus in response to an adverse in utero environment. Infantile hemangioma (IH), a vascular anomaly, is the most common tumor of infancy. Here we take IH as the tumor model to propose the stem cell teratogenic hypothesis of tumorigenesis and the potential involvement of the immune system.

OBJECTIVES

Teratogenic agents include chemicals, heavy metals, pathogens, and ionizing radiation. To investigate the etiology and pathogenesis of IH, we hypothesized that they result from a teratogenic mechanism. Immature, incompletely differentiated, dysregulated progenitor cells (multipotential stem cells) are arrested in development with vasculogenic, angiogenic, and tumorigenic potential due to exposure to teratogenic agents such as extrinsic factors that disrupt intrinsic factors via molecular mimicry. During the critical period of immunological tolerance, environmental exposure to immunotoxic agents may harness the teratogenic potential in the developing embryo or fetus and modify the early-life programming algorithm by altering normal fetal development, causing malformations, and inducing tumorigenesis. Specifically, exposure to environmental agents may interfere with physiological signaling pathways and contribute to the generation of IH, by several mechanisms.

DISCUSSION

An adverse in utero environment no longer serves as a sustainable environment for proper embryogenesis and normal development. Targeted disruption of stem cells by extrinsic factors can alter the genetic program.

CONCLUSIONS

This article offers new perspectives to stimulate discussion, explore novel experimental approaches (such as immunotoxicity/vasculotoxicity assays and novel isogenic models), and to address the questions raised to convert the hypotheses into nontoxic, noninvasive treatments.

Infiltrating Myeloid Cells Exert Protumorigenic Actions via Neutrophil Elastase

Tissue infiltration and elevated peripheral circulation of granulocytic myeloid-derived cells is associated with poor outcomes in prostate cancer and other malignancies. Although myeloid-derived cells have the ability to suppress T-cell function, little is known about the direct impact of these innate cells on prostate tumor growth. Here, it is reported that granulocytic myeloid-derived suppressor cells (MDSC) are the predominant tumor-infiltrating cells in prostate cancer xenografts established in athymic nude mice. MDSCs significantly increased in number in the peripheral circulation as a function of xenograft growth and were successfully depleted in vivo by Gr-1 antibody treatment. Importantly, MDSC depletion significantly decreased xenograft growth. We hypothesized that granulocytic MDSCs might exert their protumorigenic actions in part through neutrophil elastase (ELANE), a serine protease released upon granulocyte activation. Indeed, it was determined that NE is expressed by infiltrating immune cells and is enzymatically active in prostate cancer xenografts and in prostate tumors of prostate-specific Pten-null mice. Importantly, treatment with sivelestat, a small-molecule inhibitor specific for NE, significantly decreased xenograft growth, recapitulating the phenotype of Gr-1 MDSC depletion. Mechanistically, NE activated MAPK signaling and induced MAPK-dependent transcription of the proliferative gene cFOS in prostate cancer cells. Functionally, NE stimulated proliferation, migration, and invasion of prostate cancer cells in vitro IHC on human prostate cancer clinical biopsies revealed coexpression of NE and infiltrating CD33⁺ MDSCs.Implications: This report suggests that MDSCs and NE are physiologically important mediators of prostate cancer progression and may serve as potential biomarkers and therapeutic targets. Mol Cancer Res; 15(9); 1138-52. ©2017 AACR.

NOTCH1 and SOX10 are Essential for Proliferation and Radiation Resistance of Cancer Stem-Like Cells in Adenoid Cystic Carcinoma

PURPOSE

Although the existence of cancer stem cells (CSC) in adenoid cystic carcinoma (ACC) has been proposed, lack of assays for their propagation and uncertainty about molecular markers prevented their characterization. Our objective was to isolate CSC from ACC and provide insight into signaling pathways that support their propagation.

EXPERIMENTAL DESIGN

To isolate CSC from ACC and characterize them, we used ROCK inhibitor-supplemented cell culture, immunomagnetic cell sorting, andin vitro/in vivoassays for CSC viability and tumorigenicity.

RESULTS

We identified in ACC CD133-positive CSC that expressed NOTCH1 and SOX10, formed spheroids, and initiated tumors in nude mice. CD133(+)ACC cells produced activated NOTCH1 (N1ICD) and generated CD133(-)cells that expressed JAG1 as well as neural differentiation factors NR2F1, NR2F2, and p27Kip1. Knockdowns ofNOTCH1, SOX10, and their common effectorFABP7had negative effects on each other, inhibited spheroidogenesis, and induced cell death pointing at their essential roles in CSC maintenance. Downstream effects ofFABP7knockdown included suppression of a broad spectrum of genes involved in proliferation, ribosome biogenesis, and metabolism. Among proliferation-linked NOTCH1/FABP7 targets, we identified SKP2 and its substrate p27Kip1. A γ-secretase inhibitor, DAPT, selectively depleted CD133(+)cells, suppressed N1ICD and SKP2, induced p27Kip1, inhibited ACC growthin vivo, and sensitized CD133(+)cells to radiation.

CONCLUSIONS

These results establish in the majority of ACC the presence of a previously uncharacterized population of CD133(+)cells with neural stem properties, which are driven by SOX10, NOTCH1, and FABP7. Sensitivity of these cells to Notch inhibition and their dependence on SKP2 offer new opportunities for targeted ACC therapies.

Recapitulation of treatment response patterns in a novel humanized mouse model for chronic hepatitis B virus infection

There are ~350 million chronic carriers of hepatitis B (HBV). While a prophylactic vaccine and drug regimens to suppress viremia are available, chronic HBV infection is rarely cured. HBV's limited host tropism leads to a scarcity of susceptible small animal models and is a hurdle to developing curative therapies. Mice that support engraftment with human hepatoctyes have traditionally been generated through crosses of murine liver injury models to immunodeficient backgrounds. Here, we describe the disruption of fumarylacetoacetate hydrolase directly in the NOD Rag1^-/- IL2RγNULL (NRG) background using zinc finger nucleases. The resultant human liver chimeric mice sustain persistent HBV viremia for >90 days. When treated with standard of care therapy, HBV DNA levels decrease below detection but rebound when drug suppression is released, mimicking treatment response observed in patients. Our study highlights the utility of directed gene targeting approaches in zygotes to create new humanized mouse models for human diseases.

Infantile Hemangioma Originates From A Dysregulated But Not Fully Transformed Multipotent Stem Cell

Infantile hemangioma (IH) is the most common tumor of infancy. Its cellular origin and biological signals for uncontrolled growth are poorly understood, and specific pharmacological treatment is unavailable. To understand the process of hemangioma-genesis we characterized the progenitor hemangioma-derived stem cell (HemSC) and its lineage and non-lineage derivatives. For this purpose we performed a high-throughput (HT) phenotypic and gene expression analysis of HemSCs, and analyzed HemSC-derived tumorspheres. We found that IH is characterized by high expression of genes involved in vasculogenesis, angiogenesis, tumorigenesis and associated signaling pathways. These results show that IH derives from a dysregulated stem cell that remains in an immature, arrested stage of development. The potential biomarkers we identified can afford the development of diagnostic tools and precision-medicine therapies to "rewire" or redirect cellular transitions at an early stage, such as signaling pathways or immune response modifiers.

Nuclear TBLR1 as an ER corepressor promotes cell proliferation, migration and invasion in breast and ovarian cancer

Estrogen receptors (ER) play important roles in the development and progression of breast and ovarian cancers. ERs mediate transcriptional regulation through interaction with cofactors and binding to response elements within the regulatory elements of target genes. Here, we examined the expression and function of TBLR1/TBL1XR1, a core component of NCoR (nuclear receptor corepressor) and SMRT (silencing mediator of retinoic acid and thyroid receptor) corepressor complexes, in breast and ovarian cancers. We found that although TBLR1 is present in both the nucleus and cytoplasm of normal and neoplastic breast and ovarian cells, it is expressed at significantly higher levels in the nucleus of malignant breast and ovarian cells compared to benign cells. TBLR1 functions as an ER corepressor to inhibit ER-mediated transcriptional activation in both breast and ovarian cell lines, but it has no effect on androgen receptor (AR) mediated transcriptional activation in these cells. Furthermore, ectopic expression of nuclear TBLR1 in breast and ovarian cancer cells stimulates cell proliferation. The increased cell proliferation by nuclear TBLR1 is through both ER-independent and ER-dependent mechanisms as evidenced by increased growth in hormone-free medium and estrogen medium, as well as reduced growth with ER knockdown by siRNA. Nuclear TBLR1 overexpression also increased migration and invasion in both breast and ovarian cancer cells. Determining the functional relationship between TBLR1 and ER may provide insights to develop novel treatment strategies and improve response to hormonal therapy in breast and ovarian cancers.

Humanized mice efficiently engrafted with fetal hepatoblasts and syngeneic immune cells develop human monocytes and NK cells

BACKGROUND & AIMS

Human liver chimeric mice are useful models of human hepatitis virus infection, including hepatitis B and C virus infections. Independently, immunodeficient mice reconstituted with CD34(+) hematopoietic stem cells (HSC) derived from fetal liver reliably develop human T and B lymphocytes. Combining these systems has long been hampered by inefficient liver reconstitution of human fetal hepatoblasts. Our study aimed to enhance hepatoblast engraftment in order to create a mouse model with syngeneic human liver and immune cells.

METHODS

The effects of human oncostatin-M administration on fetal hepatoblast engraftment into immunodeficient fah(-/-) mice was tested. Mice were then transplanted with syngeneic human hepatoblasts and HSC after which human leukocyte chimerism and functionality were analyzed by flow cytometry, and mice were challenged with HBV.

RESULTS

Addition of human oncostatin-M enhanced human hepatoblast engraftment in immunodeficient fah(-/-) mice by 5-100 fold. In contrast to mice singly engrafted with HSC, which predominantly developed human T and B lymphocytes, mice co-transplanted with syngeneic hepatoblasts also contained physiological levels of human monocytes and natural killer cells. Upon infection with HBV, these mice displayed rapid and sustained viremia.

CONCLUSIONS

Our study provides a new mouse model with improved human fetal hepatoblast engraftment and an expanded human immune cell repertoire. With further improvements, this model may become useful for studying human immunity against viral hepatitis.

LAY SUMMARY

Important human pathogens such as hepatitis B virus, hepatitis C virus and human immunodeficiency virus only infect human cells which complicates the development of mouse models for the study of these pathogens. One way to make mice permissive for human pathogens is the transplantation of human cells into immune-compromised mice. For instance, the transplantation of human liver cells will allow the infection of these so-called "liver chimeric mice" with hepatitis B virus and hepatitis C virus. The co-transplantation of human immune cells into liver chimeric mice will further allow the study of human immune responses to hepatitis B virus or hepatitis C virus. However, for immunological studies it will be crucial that the transplanted human liver and immune cells are derived from the same human donor. In our study we describe the efficient engraftment of human fetal liver cells and immune cells derived from the same donor into mice. We show that liver co-engraftment resulted in an expanded human immune cell repertoire, including monocytes and natural killer cells in the liver. We further demonstrate that these mice could be infected with hepatitis B virus, which lead to an expansion of natural killer cells. In conclusion we have developed a new mouse model that could be useful to study human immune responses to human liver pathogens.

Abstract 2800: Dietary black raspberries (BRBs) inhibit tumor progression in PTEN-deficient mouse model of prostate cancer

Black raspberries (BRBs) a natural food demonstrated to have anti-oxidant, anti-inflammatory and anti-cancer activities,have been shown to inhibit oral, esophageal, mammary gland and colon cancers in rodents. Several human trials have been completed to date to assess the efficacy of BRB formulations for cancer prevention. However, the chemopreventive potential of BRBs against prostate cancer, the most commonly diagnosed malignancy and the second leading cause of death among men in the United States, is yet to be reported. Among the murine models, PTEN-mutant mice develop tumors in situ that faithfully mimic the intratumor heterogeneity observed during the progression of human prostate cancer. Therefore, we utilized this clinically relevant PTEN-mutant mouse model to evaluate the chemopreventive potential of BRBs against prostate cancer.

Genotyped 5-week-old male PTEN-mutant mice, randomly assigned to control and treatment groups (n = 12 mice/group), were fed AIN-93G diet (control) or AIN-93G diet supplemented with BRBs (5 or 10%) for 23 weeks. Age-matched non-transgenic mice (wild-type) served as experimental controls (n = 6). Animal weight and food consumption were measured during the treatment period, and the mice were euthanized at 28 weeks of age. Prostate tissues were harvested, weighed and fixed in 10% formalin for histopathological analysis. Histological, cell proliferation (Ki-67 staining) and apoptosis (TUNEL) analyses were performed to determine the chemopreventive potential of BRBs.

PTEN-mutant mice fed control or BRB (5 or 10%) diets had steady body weight gain, 16 to 18 g during the 23-week treatment. BRB diets were well tolerated as none of the animals fed BRBs exhibited any observable toxicity. PTEN-mutant mice (control) had increased prostate weight (ave. = 248 mg) relative to wild-type mouse prostate (ave. = 90 mg), and 5 and 10% BRB diets significantly (p&lt;0.01) decreased the prostate weights to ave. = 116 and 162 mg, respectively, compared to control. In addition, 5% BRBs significantly (p&lt;0.05) reduced the prostate weights compared to 10% BRBs. Histological examination of dorsolateral prostate (DLP) revealed that 98% of PTEN-mutant mice fed control diet developed invasive adenocarcinomas, whereas both 5 and 10% BRB diets significantly reduced tumor incidence and the progression of PIN lesions to invasive adenocarcinomas by 64% (p&lt;0.0001) and 43% (p&lt;0.001), respectively. Interestingly, 5% BRBs appear to be more effective than 10% BRBs (p&lt;0.01). Both 5 and 10% BRBs significantly reduced tumor cell proliferation rates and induced apoptosis, p&lt;0.0001 and p&lt;0.001, respectively. Furthermore, mice fed both 5 and 10% BRBs contained more normal appearing prostates (free from PIN lesions and adenocarcinomas), when compared to control mice (54 and 33% compared to 3%, respectively). In conclusion, our data indicate that BRBs may have significant potential for prostate cancer prevention and/or treatment.

Citation Format: Narayanan K. Narayanan, Gary D. Stoner, Daniel S. Peiffer, Karen Galdanes, Eric Larios, Alu Mark, Lisa Maziniski, Luis Chiriboga, Maarten C. Bosland. Dietary black raspberries (BRBs) inhibit tumor progression in PTEN-deficient mouse model of 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 2800. doi:10.1158/1538-7445.AM2015-2800

Hepatitis C virus infects rhesus macaque hepatocytes and simianized mice

At least 170 million people are chronically infected with hepatitis C virus (HCV). Owing to the narrow host range of HCV and restricted use of chimpanzees, there is currently no suitable animal model for HCV pathogenesis studies or the development of a HCV vaccine. To identify cellular determinants of interspecies transmission and establish a novel immunocompetent model system, we examined the ability of HCV to infect hepatocytes from a small nonhuman primate, the rhesus macaque (Macaca mulatta). We show that the rhesus orthologs of critical HCV entry factors support viral glycoprotein-dependent virion uptake. Primary hepatocytes from rhesus macaques are also permissive for HCV-RNA replication and particle production, which is enhanced when antiviral signaling is suppressed. We demonstrate that this may be owing to the diminished capacity of HCV to antagonize mitochondrial antiviral-signaling protein-dependent innate cellular defenses. To test the ability of HCV to establish persistent replication in vivo, we engrafted primary rhesus macaque hepatocytes into immunocompromised xenorecipients. Inoculation of resulting simian liver chimeric mice with either HCV genotype 1a or 2a resulted in HCV serum viremia for up to 10 weeks.

CONCLUSION

Together, these data indicate that rhesus macaques may be a viable model for HCV and implicate host immunity as a potential species-specific barrier to HCV infection. We conclude that suppression of host immunity or further viral adaptation may allow robust HCV infection in rhesus macaques and creation of a new animal model for studies of HCV pathogenesis, lentivirus coinfection, and vaccine development.

Broadly neutralizing antibodies abrogate established hepatitis C virus infection

In most exposed individuals, hepatitis C virus (HCV) establishes a chronic infection; this long-term infection in turn contributes to the development of liver diseases such as cirrhosis and hepatocellular carcinoma. The role of antibodies directed against HCV in disease progression is poorly understood. Neutralizing antibodies (nAbs) can prevent HCV infection in vitro and in animal models. However, the effects of nAbs on an established HCV infection are unclear. We demonstrate that three broadly nAbs-AR3A, AR3B, and AR4A-delivered with adeno-associated viral vectors can confer protection against viral challenge in humanized mice. Furthermore, we provide evidence that nAbs can abrogate an ongoing HCV infection in primary hepatocyte cultures and in a human liver chimeric mouse model. These results showcase a therapeutic approach to interfere with HCV infection by exploiting a previously unappreciated need for HCV to continuously infect new hepatocytes to sustain a chronic infection.

Resiquimod as an immunologic adjuvant for NY-ESO-1 protein vaccination in patients with high-risk melanoma

The Toll-like receptor (TLR) 7/8 agonist resiquimod has been used as an immune adjuvant in cancer vaccines. We evaluated the safety and immunogenicity of the cancer testis antigen NY-ESO-1 given in combination with Montanide (Seppic) with or without resiquimod in patients with high-risk melanoma. In part I of the study, patients received 100 μg of full-length NY-ESO-1 protein emulsified in 1.25 mL of Montanide (day 1) followed by topical application of 1,000 mg of 0.2% resiquimod gel on days 1 and 3 (cohort 1) versus days 1, 3, and 5 (cohort 2) of a 21-day cycle. In part II, patients were randomized to receive 100-μg NY-ESO-1 protein plus Montanide (day 1) followed by topical application of placebo gel [(arm A; n = 8) or 1,000 mg of 0.2% resiquimod gel (arm B; n = 12)] using the dosing regimen established in part I. The vaccine regimens were generally well tolerated. NY-ESO-1-specific humoral responses were induced or boosted in all patients, many of whom had high titer antibodies. In part II, 16 of 20 patients in both arms had NY-ESO-1-specific CD4⁺ T-cell responses. CD8⁺ T-cell responses were only seen in 3 of 12 patients in arm B. Patients with TLR7 SNP rs179008 had a greater likelihood of developing NY-ESO-1-specific CD8⁺ responses. In conclusion, NY-ESO-1 protein in combination with Montanide with or without topical resiquimod is safe and induces both antibody and CD4⁺ T-cell responses in the majority of patients; the small proportion of CD8⁺ T-cell responses suggests that the addition of topical resiquimod to Montanide is not sufficient to induce consistent NY-ESO-1-specific CD8⁺ T-cell responses.

A link between premenopausal iron deficiency and breast cancer malignancy

Background

Young breast cancer (BC) patients less than 45 years old are at higher risk of dying from the disease when compared to their older counterparts. However, specific risk factors leading to this poorer outcome have not been identified.

Methods

One candidate is iron deficiency, as this is common in young women and a clinical feature of young age. In the present study, we used immuno-competent and immuno-deficient mouse xenograft models as well as hemoglobin as a marker of iron status in young BC patients to demonstrate whether host iron deficiency plays a pro-metastatic role.

Results

We showed that mice fed an iron-deficient diet had significantly higher tumor volumes and lung metastasis compared to those fed normal iron diets. Iron deficiency mainly altered Notch but not TGF-β and Wnt signaling in the primary tumor, leading to the activation of epithelial mesenchymal transition (EMT). This was revealed by increased expression of Snai1 and decreased expression of E-cadherin. Importantly, correcting iron deficiency by iron therapy reduced primary tumor volume, lung metastasis, and reversed EMT markers in mice. Furthermore, we found that mild iron deficiency was significantly associated with lymph node invasion in young BC patients (p<0.002).

Conclusions

Together, our finding indicates that host iron deficiency could be a contributor of poor prognosis in young BC patients.