Stem cell dynamics and cellular heterogeneity across lineage subtypes of castrate resistant prostate cancer

To resist lineage-dependent therapies such as androgen receptor inhibition, prostate luminal epithelial adenocarcinoma cells often adopt a stem-like state resulting in lineage-plasticity and phenotypic heterogeneity. Castrate resistant prostate adenocarcinoma can transition to neuroendocrine and occasionally to amphicrine, co-expressed luminal and neuroendocrine, phenotypes. We developed CRPC patient-derived organoid models that preserve heterogeneity of the originating tumor, including an amphicrine model displaying a range of luminal and neuroendocrine phenotypes. To gain biological insight and to identify potential treatment targets within heterogeneous tumor cell populations, we assessed the lineage hierarchy and molecular characteristics of various CRPC tumor subpopulations. Transcriptionally similar stem/progenitor cells were identified for all lineage populations. Lineage tracing in amphicrine CRPC showed that heterogeneity originated from distinct subclones of infrequent stem/progenitor cells that produced mainly quiescent differentiated amphicrine progeny. By contrast, adenocarcinoma CRPC progeny originated from stem/progenitor cells and self-renewing differentiated luminal cells. NEPC was composed almost exclusively of self-renewing stem/progenitor cells. Amphicrine subpopulations were enriched for secretory luminal, mesenchymal, and enzalutamide treatment persistent signatures that characterize clinical progression. Finally, the amphicrine stem/progenitor subpopulation was specifically depleted with an AURKA inhibitor, which blocked tumor growth. These data illuminate distinct stem cell characteristics for subtype-specific CRPC in addition to demonstrating a context for targeting differentiation-competent prostate stem cells.

Localized high-risk prostate cancer harbors an androgen receptor low subpopulation susceptible to HER2 inhibition

Patients diagnosed with localized high-risk prostate cancer have higher rates of recurrence, and the introduction of neoadjuvant intensive hormonal therapies seeks to treat occult micrometastatic disease by their addition to definitive treatment. Sufficient profiling of baseline disease has remained a challenge in enabling the in-depth assessment of phenotypes associated with exceptional vs. poor pathologic responses after treatment. In this study, we report comprehensive and integrative gene expression profiling of 37 locally advanced prostate tumors prior to six months of androgen deprivation therapy (ADT) plus the androgen receptor (AR) inhibitor enzalutamide prior to radical prostatectomy. A robust transcriptional program associated with HER2 activity was positively associated with poor outcome and opposed AR activity, even after adjusting for common genomic alterations in prostate cancer including PTEN loss and expression of the TMPRSS2:ERG fusion. Patients experiencing exceptional pathologic responses demonstrated lower levels of HER2 and phospho-HER2 by immunohistochemistry of biopsy tissues. The inverse correlation of AR and HER2 activity was found to be a universal feature of all aggressive prostate tumors, validated by transcriptional profiling an external cohort of 121 patients and immunostaining of tumors from 84 additional patients. Importantly, the AR activity-low, HER2 activity-high cells that resist ADT are a pre-existing subset of cells that can be targeted by HER2 inhibition alone or in combination with enzalutamide. In summary, we show that prostate tumors adopt an AR activity-low prior to antiandrogen exposure that can be exploited by treatment with HER2 inhibitors.

GZMK+CD8+ T cells Target a Specific Acinar Cell Type in Sjögren's Disease

Sjögren's Disease (SjD) is a systemic autoimmune disease without a clear etiology or effective therapy. Utilizing unbiased single-cell and spatial transcriptomics to analyze human minor salivary glands in health and disease we developed a comprehensive understanding of the cellular landscape of healthy salivary glands and how that landscape changes in SjD patients. We identified novel seromucous acinar cell types and identified a population of PRR4+CST3+WFDC2- seromucous acinar cells that are particularly targeted in SjD. Notably, GZMK+CD8 T cells, enriched in SjD, exhibited a cytotoxic phenotype and were physically associated with immune-engaged epithelial cells in disease. These findings shed light on the immune response's impact on transitioning acinar cells with high levels of secretion and explain the loss of this specific cell population in SjD. This study explores the complex interplay of varied cell types in the salivary glands and their role in the pathology of Sjögren's Disease.

Immune niches in brain metastases contain TCF1+ stem-like T cells, are associated with disease control and are modulated by preoperative SRS

The CD8+ T-cell response is prognostic for survival outcomes in several tumor types. However, whether this extends to tumors in the brain, an organ with barriers to T cell entry, remains unclear. Here, we analyzed immune infiltration in 67 brain metastasis (BrM) and found high frequencies of PD1+ TCF1+ stem-like CD8+ T-cells and TCF1- effector-like cells. Importantly, the stem-like cells aggregate with antigen presenting cells in immune niches, and niches were prognostic for local disease control. Standard of care for BrM is resection followed by stereotactic radiosurgery (SRS), so to determine SRS's impact on the BrM immune response, we examined 76 BrM treated with pre-operative SRS (pSRS). pSRS acutely reduced CD8+ T cells at 3 days. However, CD8+ T cells rebounded by day 6, driven by increased frequency of effector-like cells. This suggests that the immune response in BrM can be regenerated rapidly, likely by the local TCF1+ stem-like population.

Abstract B050: Reproducible and effective preclinical models of prostate cancer metastasis established with PDXs

Metastatic castration resistant prostate cancer (mCRPC) is a lethal disease. Understanding the intricacy of this disease and developing targeted treatment is hampered by the lacking of clinically relevant animal models. LuCaP patient-derived xenografts (PDXs), established from advanced metastatic prostate cancer, are a large cohort that encompass the molecular and cellular heterogeneity of mCRPC. We have established four prostate cancer metastasis models from three androgen receptor (AR) positive lines (LuCaP136, LuCaP167 and LuCaP23.1) and one AR negative line LuCap145.2. The three AR positive LuCap lines metastasized to vertebrae and long bones with differing bone-associated histology while the AR negative LuCap145.2 metastasize to brain and spinal cord. The bone metastasis phenotypes of the models encompass: osteolytic (LuCaP136), mixed bone destruction and new bone formation (LuCaP167), and a highly osteoblastic histology (LuCaP23.1). LuCap136 and LuCap167 also metasize to soft tissues including adrenal, kidney and liver. Castration responses were studied on LuCap136 and LuCap167 models. Although both models are castration resistant, LuCap136 model initially are sensitive to castration with decreased tumor progression, and AR down-regulated in the metastatic sites. In contrast, tumor progression was not affected after castration in LuCap167 model. AR and ARV7 were up-regulated in metastatic cells. In summary, the LuCap PDX lines have the capacity for systemic growth in clinically accurate metastatic sites. In addition, the two AR positive models show different castration response which may be driven by different pathways. Understanding the complexity of these pathways would guide optimal selection of drug combinations to achieve the best outcome for patients with mCRPC.

Citation Format: JuanJuan I. Yin, Asha Daryanani, Aian Alilin, Ross Lake, Kathy Kelly. Reproducible and effective preclinical models of prostate cancer metastasis established with PDXs [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B050.

First Leptophobic Dark Matter Search from the Coherent-CAPTAIN-Mills Liquid Argon Detector

We report the first results of a search for leptophobic dark matter (DM) from the Coherent-CAPTAIN-Mills (CCM) liquid argon (LAr) detector. An engineering run with 120 photomultiplier tubes (PMTs) and 17.9×10^{20} protons on target (POT) was performed in fall 2019 to study the characteristics of the CCM detector. The operation of this 10-ton detector was strictly light based with a threshold of 50 keV and used coherent elastic scattering off argon nuclei to detect DM. Despite only 1.5 months of accumulated luminosity, contaminated LAr, and nonoptimized shielding, CCM's first engineering run has already achieved sensitivity to previously unexplored parameter space of light dark matter models with a baryonic vector portal. With an expected background of 115 005 events, we observe 115 005+16.5 events which is compatible with background expectations. For a benchmark mediator-to-DM mass ratio of m_{V_{B}}/m_{χ}=2.1, DM masses within the range 9  MeV≲m_{χ}≲50  MeV are excluded at 90% C. L. in the leptophobic model after applying the Feldman-Cousins test statistic. CCM's upgraded run with 200 PMTs, filtered LAr, improved shielding, and 10 times more POT will be able to exclude the remaining thermal relic density parameter space of this model, as well as probe new parameter space of other leptophobic DM models.

Clinical outcome following checkpoint therapy in renal cell carcinoma is associated with a burst of activated CD8 T cells in blood

PURPOSE

Checkpoint therapy is now the cornerstone of treatment for patients with renal cell carcinoma (RCC) with advanced disease, but biomarkers are lacking to predict which patients will benefit. This study proposes potential immunological biomarkers that could developed for predicting therapeutic response in patients with RCC.

METHODS

Using flow cytometry, RNA sequencing, and T-cell receptor (TCR) sequencing, we investigated changes in T cells in the peripheral blood of patients with advanced RCC after receiving immunotherapy. We used immunofluorescence (IF) imaging and flow cytometry to investigate how intratumoral T cells in patients' tumors (resected months/years prior to receiving checkpoint therapy) predicted patient outcomes after immunotherapy.

RESULTS

We found that a small proportion of CD4 and CD8 T cells in the blood activate following checkpoint therapy, expressing the proliferation marker Ki67 and activation markers HLA-DR and CD38. Patients who had the highest increase in these HLA-DR +CD38+CD8 T cells after treatment had the best antitumor immune response and experienced clinical benefit. Using RNA sequencing, we found that while these cells expanded in most patients, their phenotype did not drastically change during treatment. However, when we analyzed the TCR repertoire of these HLA-DR +CD38+CD8+T cells, we found that only patients who clinically benefitted had a burst of new clonotypes enter this pool of activated cells. Finally, we found that abundant T cells in the untreated tumors predicted clinical benefit to checkpoint therapy on disease progression.

CONCLUSIONS

Together, these data suggest that having a strong pre-existing immune response and immediate peripheral T-cell activation after checkpoint therapy is a predictor of clinical benefit in patients with RCC.

Differential organization of open field behavior in mice following acute or chronic simulated GCR exposure

Astronauts undertaking deep space travel will receive chronic exposure to the mixed spectrum of particles that comprise Galactic Cosmic Radiation (GCR). Exposure to the different charged particles of varied fluence and energy that characterize GCR may impact neural systems that support performance on mission critical tasks. Indeed, growing evidence derived from years of terrestrial-based simulations of the space radiation environment using rodents has indicated that a variety of exposure scenarios can result in significant and long-lasting decrements to CNS functionality. Many of the behavioral tasks used to quantify radiation effects on the CNS depend on neural systems that support maintaining spatial orientation and organization of rodent open field behavior. The current study examined the effects of acute or chronic exposure to simulated GCR on the organization of open field behavior under conditions with varied access to environmental cues in male and female C57BL/6 J mice. In general, groups exhibited similar organization of open field behavior under dark and light conditions. Two exceptions were noted: the acute exposure group exhibited significantly slower and more circuitous homeward progressions relative to the chronic group under light conditions. These results demonstrate the potential of open field behavior organization to discriminate between the effects of select GCR exposure paradigms.

A Subset of Localized Prostate Cancer Displays an Immunogenic Phenotype Associated with Losses of Key Tumor Suppressor Genes

PURPOSE

A subset of primary prostate cancer expresses programmed death-ligand 1 (PD-L1), but whether they have a unique tumor immune microenvironment or genomic features is unclear.

EXPERIMENTAL DESIGN

We selected PD-L1-positive high-grade and/or high-risk primary prostate cancer, characterized tumor-infiltrating lymphocytes with multiplex immunofluorescence, and identified genomic alterations in immunogenic and nonimmunogenic tumor foci.

RESULTS

One quarter of aggressive localized prostate cancer cases (29/115) had tumor PD-L1 expression more than 5%. This correlated with increased density of CD8⁺ T cells, a large fraction coexpressing PD-1, versus absent PD-1 expression on sparse CD8 T cells in unselected cases. Most CD8⁺PD-1⁺ cells did not express terminal exhaustion markers (TIM3 or LAG3), while a subset expressed TCF1. Consistent with these CD8⁺PD-1⁺TCF1⁺ cells being progenitors, they were found in antigen-presenting cell niches in close proximity to MHC-II⁺ cells. CD8 T-cell density in immunogenic prostate cancer and renal cell carcinoma (RCC) was nearly identical. Shallow RB1 and BRCA2 losses, and deep deletions of CHD1, were prevalent, the latter being strongly associated with a dendritic cell gene set in The Cancer Genome Atlas. Tumor mutation burden was variable; neither high microsatellite instability nor CDK12 alterations were present.

CONCLUSIONS

A subset of localized prostate cancer is immunogenic, manifested by PD-L1 expression and CD8⁺ T-cell content comparable with RCC. The CD8⁺ T cells include effector cells and exhausted progenitor cells, which may be expanded by immune checkpoint inhibitors (ICI). Genomic losses of RB1, BRCA2, and CHD1 may be drivers of this phenotype. These findings indicate that immunotherapies may be effective in biomarker-selected subpopulations of patients with localized prostate cancer.

ZBP1 not RIPK1 mediates tumor necroptosis in breast cancer

Tumor necrosis happens commonly in advanced solid tumors. We reported that necroptosis plays a major role in tumor necrosis. Although several key necroptosis regulators including receptor interacting protein kinase 1 (RIPK1) have been identified, the regulation of tumor necroptosis during tumor development remains elusive. Here, we report that Z-DNA-binding protein 1 (ZBP1), not RIPK1, mediates tumor necroptosis during tumor development in preclinical cancer models. We found that ZBP1 expression is dramatically elevated in necrotic tumors. Importantly, ZBP1, not RIPK1, deletion blocks tumor necroptosis during tumor development and inhibits metastasis. We showed that glucose deprivation triggers ZBP1-depedent necroptosis in tumor cells. Glucose deprivation causes mitochondrial DNA (mtDNA) release to the cytoplasm and the binding of mtDNA to ZBP1 to activate MLKL in a BCL-2 family protein, NOXA-dependent manner. Therefore, our study reveals ZBP1 as the key regulator of tumor necroptosis and provides a potential drug target for controlling tumor metastasis.

Abstract PO-041: An immunologic niche of antigen presenting cells and stem-like CD8+ T-cells is present in non-small cell lung cancer brain metastases

Background: Non-small cell lung cancer (NSCLC) patients with brain metastases have a very poor prognosis. The first line treatments for NSCLC brain metastases are typically surgery and pre- or post-operative stereotactic radiosurgery (SRS) or SRS alone. However, subsequent intra-cranial failure and death is common. Importantly, we have previously shown that a unique immune niche in genitourinary malignancies correlates with the risk for disease recurrence. Accordingly, here we investigated whether this immune niche was present in brain metastases, whether it correlated with patient outcomes, and whether it was modulated by SRS. Methods: Formalin fixed paraffin embedded brain metastases were stained by immunofluorescence for CD8, PD-1, TCF-1, MHC-II and DAPI. Following successful image acquisition using fluorescent whole slide scanning, we used a custom quantitative analysis pipeline to measure the cellularity, relative cellular locations, local cellular density, and marker staining intensity. Results: We identified immune niches consisting of both stem-like TCF-1+ CD8+ T-cells and antigen presenting cells (MHC-II+) in brain metastases. TCF-1+ CD8+ T-cells were found at in areas of higher MHC-II+ cell density than the TCF-1 CD8+negative T-cells. The amount of tumor issue occupied by immune niches correlated with TCF1+ CD8+ T-cell infiltration, as well as with total CD8+ T-cell and MHC-II+ cell infiltration. Importantly, we found that higher MHC-II+ cell density correlated with longer overall survival in this cohort of patients. Additionally, we found this immune niche is preserved following pre-operative SRS. Conclusions: Our study is the first to demonstrate stem-like CD8+ T-cells in brain metastases and that these cells form an immune niche similar to those described extra-cranial tumor sites. Additionally, we report that the immune niche is preserved following SRS, which is highly clinically relevant to the use of combinatorial strategies between SRS and checkpoint blockade.

Citation Format: Caroline S. Jansen, Luke del Balzo, Roshan Prabhu, Suzanna Logan, Prasanthi Chappa, Kirtesh Patel, Scott Wilkinson, Ross Lake, Hui-Kuo G. Shu, Jim Zhong, Vishal Dhere, Jeffrey Olson, Adam G. Sowalsky, Mohammad K. Khan, Haydn T. Kissick, Zachary S. Buchwald. An immunologic niche of antigen presenting cells and stem-like CD8+ T-cells is present in non-small cell lung cancer brain metastases [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-041.

A novel structure associated with aging is augmented in the DPP6-KO mouse brain

In addition to its role as an auxiliary subunit of A-type voltage-gated K⁺ channels, we have previously reported that the single transmembrane protein Dipeptidyl Peptidase Like 6 (DPP6) impacts neuronal and synaptic development. DPP6-KO mice are impaired in hippocampal-dependent learning and memory and exhibit smaller brain size. Using immunofluorescence and electron microscopy, we report here a novel structure in hippocampal area CA1 that was significantly more prevalent in aging DPP6-KO mice compared to WT mice of the same age and that these structures were observed earlier in development in DPP6-KO mice. These novel structures appeared as clusters of large puncta that colocalized NeuN, synaptophysin, and chromogranin A. They also partially labeled for MAP2, and with synapsin-1 and VGluT1 labeling on their periphery. Electron microscopy revealed that these structures are abnormal, enlarged presynaptic swellings filled with mainly fibrous material with occasional peripheral, presynaptic active zones forming synapses. Immunofluorescence imaging then showed that a number of markers for aging and especially Alzheimer’s disease were found as higher levels in these novel structures in aging DPP6-KO mice compared to WT. Together these results indicate that aging DPP6-KO mice have increased numbers of novel, abnormal presynaptic structures associated with several markers of Alzheimer’s disease.

MEIS1 down-regulation by MYC mediates prostate cancer development through elevated HOXB13 expression and AR activity

Localized prostate cancer develops very slowly in most men, with the androgen receptor (AR) and MYC transcription factors amongst the most well-characterized drivers of prostate tumorigenesis. Canonically, MYC up-regulation in luminal prostate cancer cells functions to oppose the terminally differentiating effects of AR. However, the effects of MYC up-regulation are pleiotropic and inconsistent with a poorly proliferative phenotype. Here we show that increased MYC expression and activity are associated with the down-regulation of MEIS1, a HOX-family transcription factor. Using RNA-seq to profile a series of human prostate cancer specimens laser capture microdissected on the basis of MYC immunohistochemistry, MYC activity, and MEIS1 expression were inversely correlated. Knockdown of MYC expression in prostate cancer cells increased the expression of MEIS1 and increased the occupancy of MYC at the MEIS1 locus. Finally, we show in laser capture microdissected human prostate cancer samples and the prostate TCGA cohort that MEIS1 expression is inversely proportional to AR activity as well as HOXB13, a known interacting protein of both AR and MEIS1. Collectively, our data demonstrate that elevated MYC in a subset of primary prostate cancers functions in a negative role in regulating MEIS1 expression, and that this down-regulation may contribute to MYC-driven development and progression.

Multiple primary prostate tumors with differential drug sensitivity

342

Background: The differential aggressiveness of potentially independent prostate cancer clones remains largely unknown. Appropriate prostate cancer staging using mpMRI and biopsy tissue can be confounded by sampling error. To date, there has been no understanding of whether clonal variability influences management decisions for localized prostate tumors. We sought to identify the sensitivity and genomic profile of distinct localized tumors from a patient following systemic intense neoadjuvant androgen deprivation therapy (ADT). Methods: A 66-year-old man with high risk prostate cancer enrolled in a Phase 2 study of intense neoadjuvant ADT (goserelin + enzalutamide; inADT). Baseline mpMRI showed a single semi-contiguous lesion encompassing the right apical-mid PZ extending into the left distal apical PZ. MR/US-fusion targeted biopsy was performed before 6 months of inADT. A second mpMRI was performed before radical prostatectomy. Whole exome sequencing on microdissected tumor foci identified somatic mutations and copy number alterations, which were further used with immunohistochemistry to assess tumor clonal architecture and genomic/phenotypic evolution of treatment resistant tumor. Results: We found two clonally independent tumors exhibited intrinsic heterogeneity at baseline which correlated with response or resistance. Biopsies of distinct left- and right-sided tumors showed differing histologies. mpMRI and pathology showed near complete response of the left-sided tumor and substantial resistance of the right-sided tumor, which exhibited a large intraductal component. Histology and whole exome data highlighted a divergence in the status of PTEN and TP53, tumor suppressor genes implicated in prostate cancer progression. Conclusions: These data highlight that even nascent prostate cancer is heterogenous and neoadjuvant therapeutic strategies will need to consider this for clinical optimization. Evolutionary trajectories that resulted in tumor heterogeneity in this case likely contributed to our observation that two independent prostate tumor nodules with distinct genetic alterations responded differently to neoadjuvant intense ADT. Clinical trial information: NCT02430480.

A case report of multiple primary prostate tumors with differential drug sensitivity

Localized prostate cancers are genetically variable and frequently multifocal, comprising spatially distinct regions with multiple independently-evolving clones. To date there is no understanding of whether this variability can influence management decisions for patients with prostate tumors. Here, we present a single case from a clinical trial of neoadjuvant intense androgen deprivation therapy. A patient was diagnosed with a large semi-contiguous tumor by imaging, histologically composed of a large Gleason score 9 tumor with an adjacent Gleason score 7 nodule. DNA sequencing demonstrates these are two independent tumors, as only the Gleason 9 tumor harbors single-copy losses of PTEN and TP53. The PTEN/TP53-deficient tumor demonstrates treatment resistance, selecting for subclones with mutations to the remaining copies of PTEN and TP53, while the Gleason 7 PTEN-intact tumor is almost entirely ablated. These findings indicate that spatiogenetic variability is a major confounder for personalized treatment of patients with prostate cancer.

An intra-tumoral niche maintains and differentiates stem-like CD8 T cells

Tumour-infiltrating lymphocytes are associated with a survival benefit in several tumour types and with the response to immunotherapy^1-8. However, the reason some tumours have high CD8 T cell infiltration while others do not remains unclear. Here we investigate the requirements for maintaining a CD8 T cell response against human cancer. We find that CD8 T cells within tumours consist of distinct populations of terminally differentiated and stem-like cells. On proliferation, stem-like CD8 T cells give rise to more terminally differentiated, effector-molecule-expressing daughter cells. For many T cells to infiltrate the tumour, it is critical that this effector differentiation process occur. In addition, we show that these stem-like T cells reside in dense antigen-presenting-cell niches within the tumour, and that tumours that fail to form these structures are not extensively infiltrated by T cells. Patients with progressive disease lack these immune niches, suggesting that niche breakdown may be a key mechanism of immune escape.

Determination of Percentage of RoundUp Ready® Soya in Soya Flour Using Real-Time Polymerase Chain Reaction: Interlaboratory Study

An interlaboratory study was conducted to evaluate a method for determination of the percentage of RoundUp Ready® (RR) soya in soya flour using Taqman® technology. The method included DNA extraction from the test portion with cetyltrimethylammonium bromide buffer followed by chloroform extraction and Wizard® resin cleanup steps. The DNA was then assayed with primer and probe sets specific for lectin as the endogenous control and the RR insert as the target. The percentage of RR soya in the soya fraction of the sample was calculated by using a matrix-matched standard curve. Ten samples of split-level blind duplicates were sent to 22 laboratories in 12 countries worldwide. Test portions contained 0, 0.5, 0.7, 1.6, 2, and 3.9% (w/w) RR soya prepared gravimetrically from commercially available RR standard reference materials. Based on the results for test materials, the relative standard deviation for repeatability (RSDr) for the method ranged from 9.3 to 19.3% and, for reproducibility (RSDR), ranged from 20.3 to 33.7%.

Platelets Promote Metastasis via Binding Tumor CD97 Leading to Bidirectional Signaling that Coordinates Transendothelial Migration

Tumor cells initiate platelet activation leading to the secretion of bioactive molecules, which promote metastasis. Platelet receptors on tumors have not been well-characterized, resulting in a critical gap in knowledge concerning platelet-promoted metastasis. We identify a direct interaction between platelets and tumor CD97 that stimulates rapid bidirectional signaling. CD97, an adhesion G protein-coupled receptor (GPCR), is an overexpressed tumor antigen in several cancer types. Purified CD97 extracellular domain or tumor cell-associated CD97 stimulated platelet activation. CD97-initiated platelet activation led to granule secretion, including the release of ATP, a mediator of endothelial junction disruption. Lysophosphatidic acid (LPA) derived from platelets induced tumor invasiveness via proximal CD97-LPAR heterodimer signaling, coupling coincident tumor cell migration and vascular permeability to promote transendothelial migration. Consistent with this, CD97 was necessary for tumor cell-induced vascular permeability in vivo and metastasis formation in preclinical models. These findings support targeted blockade of tumor CD97 as an approach to ameliorate metastatic spread.

Low Abundance of Circulating Tumor DNA in Localized Prostate Cancer

PURPOSE

Despite decreased screening-based detection of clinically insignificant tumors, most diagnosed prostate cancers are still indolent, indicating a need for better strategies for detection of clinically significant disease before treatment. We hypothesized that patients with detectable circulating tumor DNA (ctDNA) were more likely to harbor aggressive disease.

METHODS

We applied ultra-low-pass whole-genome sequencing to profile cell-free DNA from 112 patients diagnosed with localized prostate cancer and performed targeted resequencing of plasma DNA for somatic mutations previously identified in matched solid tumor in nine cases. We also performed similar analyses of data from patients with metastatic prostate cancer.

RESULTS

In all cases of localized prostate cancer, even in clinically high-risk patients who subsequently had recurrent disease, ultra-low-pass whole-genome sequencing and targeted resequencing did not detect ctDNA in plasma acquired before surgery or before recurrence. In contrast, using both approaches, ctDNA was detected in patients with metastatic prostate cancer.

CONCLUSION

Our findings demonstrate clear differences between localized and advanced prostate cancer with respect to the dissemination and detectability of ctDNA. Because allele-specific alterations in ctDNA are below the threshold for detection in localized prostate cancer, other approaches to identify cell-free nucleic acids of tumor origin may demonstrate better specificity for aggressive disease.

Abstract 2510: Combining genetic and histopathologic features to predict response to anti-androgen therapy in aggressive prostate cancer

Background: Genetic alterations in lethal, metastatic prostate cancer include the loss of PTEN, translocation of the TMPRSS2 and ERG genes, upregulation of the androgen receptor (AR), and disruption of the DNA homologous repair pathway driven by mutations to BRCA1, BRCA2, and ATM. Many of these mutations can be observed while the cancer is still localized in the prostate. Here, we seek to identify genetic features indicative of therapeutic response and novel drivers of cancer progression to inform clinical practice.

Methods: Using tissue from 33 patients in an intense neoadjuvant anti-androgen clinical trial at the NCI (NCT02430480), we examined genetic features that would predict exceptional or poor response to anti-androgen enzalutamide therapy. Each patient on trial presented with multiple tumor foci, allowing us to investigate the intratumoral heterogeneity across foci within individual patients, as well as investigating the tumor profiles across multiple patients. Several patients exhibited exceptional response with residual tumor burdens less than 0.5cc, while others had substantial treatment-resistant cancers. We developed a panel of 12 immunohistopathological stains and used this panel to guide laser capture microdissection on pre-treatment biopsies and spatially matched post-treatment radical prostatectomy specimens to isolate ultrapure tumor foci from each patient. DNA from these foci was used for whole exome sequencing, as somatic copy number alterations and mutations also confirm their evolutionary relationship. This enabled us to classify baseline specimens as responder or nonresponder, while examining variations in genetic features between the two cohorts.

Results: To date, focal PTEN loss was observed in all nonresponders, while focal ERG staining was absent in 100% of responders and present in 60% of nonresponders. Synaptophysin positivity was rare at baseline but predicted resistance to treatment with 100% sensitivity. Intriguingly, baseline copy number profiles highlight a 6q deletion in 100% of exceptional responders, but not in the non-responders. Together, these data suggest an immunostain panel to assess oncogene and tumor suppressor alterations can predict response to anti-androgen therapy, while also suggesting a novel role of 6q in resistance to anti-androgen hormone therapy. Current studies are examining the role of 6q in response to anti-androgen therapies, which remains an area of active interest in our laboratory.

Conclusions: These findings demonstrate the feasibility in identifying intratumoral heterogeneity based on prostate biomarker status both in pre-treatment and post-treatment specimens. Using these data, comprehensive molecular analysis of prostate cancer at diagnosis may better-enable physicians to predict response to anti-androgen therapy and provide tailored treatment based on gene expression status.

Citation Format: Scott Wilkinson, Huihui Ye, Nicole Carrabba, Rayann Atway, Shana Y. Trostel, Thomas Hennigan, Ross Lake, Stephanie Harmon, Guinevere Chun, Baris Turkbey, Peter A. Pinto, Peter L. Choyke, Fatima Karzai, David J. VanderWeele, Kathleen Kelly, William L. Dahut, Adam G. Sowalsky. Combining genetic and histopathologic features to predict response to anti-androgen therapy in aggressive prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2510.

Molecular and histopathologic correlates of imaging and biological responses to neoadjuvant GnRH agonist plus enzalutamide for high risk prostate cancer

34

Background: AR directed therapies are standard of care for metastatic prostate cancer, and their use for high-risk localized disease may improve survival. Previous trials showed low rates of complete pathologic responses to neoadjuvant ADT. The underlying biology and molecular features of tumors that fail to respond remain unknown. Methods: Men with localized prostate cancer with high risk features received 6 months of GnRH agonist plus enzalutamide. mpMRI was performed at baseline and prior to RP. MRI-US fusion guided biopsies were performed at study enrollment. RP specimens were sectioned in the same plane as mpMRI. Imaging and anatomical landmarks on pre- and post-treatment mpMRI were used to match targeted biopsies to RPs. IHC stains including AR, GR, and SYP were performed to guide laser capture microdissection (LCM) and characterization of residual disease. DNA was extracted from LCM biopsy and RP tissues. Whole exome sequencing with somatic mutation calling and copy number analysis was performed. Results: Most patients showed incomplete pathologic responses despite reductions in tumor volume. Several patients harbored multiple tumor clones prior to treatment, distinguished by distinct copy number alterations and mutations in biopsies. Alignment of biopsies to pre- and post-treatment mpMRI correlated with imaging response and histopathology of matched RP sections. Minimal genomic divergence from untreated clones on biopsy suggested intrinsic resistance, while extensive divergence indicated selection for pre-existing subclones. Most residual tumor was AR- and GR-positive adenocarcinoma, with some regions of AR-negative Panneth cell-like differentiation positive for synaptophysin. AR-V7 was rare in residual tumor and < 1% cells were positive for KI-67. The most common alteration in all samples was single-copy loss of chromosome 16q overlapping with ZFHX3. Conclusions: Our approach of repeated sampling by matching targeted biopsies to mpMRI demonstrates feasibility in comparing mpMRI response, pathologic treatment response, and the underlying genomic features that drive tumor development versus treatment resistance. Clinical trial information: NCT02430480.

Carfilzomib potentiates CUDC-101-induced apoptosis in anaplastic thyroid cancer

Anaplastic thyroid cancer (ATC) is one of the most aggressive human malignancies, with no effective treatment currently available. Previously, we identified agents active against ATC cells, both in vitro and in vivo, using quantitative high-throughput screening of 3282 clinically approved drugs and small molecules. Here, we report that combining two of these active agents, carfilzomib, a second-generation proteasome inhibitor, and CUDC-101, a histone deacetylase and multi-kinase inhibitor, results in increased, synergistic activity in ATC cells. The combination of carfilzomib and CUDC-101 synergistically inhibited cellular proliferation and caused cell death in multiple ATC cell lines harboring various driver mutations observed in human ATC tumors. This increased anti-ATC effect was associated with a synergistically enhanced G2/M cell cycle arrest and increased caspase 3/7 activity induced by the drug combination. Mechanistically, treatment with carfilzomib and CUDC-101 increased p21 expression and poly (ADP-ribose) polymerase protein cleavage. Our results suggest that combining carfilzomib and CUDC-101 would offer an effective therapeutic strategy to treat ATC.

Stepped-wedge cluster randomised controlled trial to assess the effectiveness of an electronic medication management system to reduce medication errors, adverse drug events and average length of stay at two paediatric hospitals: a study protocol

INTRODUCTION

Medication errors are the most frequent cause of preventable harm in hospitals. Medication management in paediatric patients is particularly complex and consequently potential for harms are greater than in adults. Electronic medication management (eMM) systems are heralded as a highly effective intervention to reduce adverse drug events (ADEs), yet internationally evidence of their effectiveness in paediatric populations is limited. This study will assess the effectiveness of an eMM system to reduce medication errors, ADEs and length of stay (LOS). The study will also investigate system impact on clinical work processes.

METHODS AND ANALYSIS

A stepped-wedge cluster randomised controlled trial (SWCRCT) will measure changes pre-eMM and post-eMM system implementation in prescribing and medication administration error (MAE) rates, potential and actual ADEs, and average LOS. In stage 1, 8 wards within the first paediatric hospital will be randomised to receive the eMM system 1 week apart. In stage 2, the second paediatric hospital will randomise implementation of a modified eMM and outcomes will be assessed. Prescribing errors will be identified through record reviews, and MAEs through direct observation of nurses and record reviews. Actual and potential severity will be assigned. Outcomes will be assessed at the patient-level using mixed models, taking into account correlation of admissions within wards and multiple admissions for the same patient, with adjustment for potential confounders. Interviews and direct observation of clinicians will investigate the effects of the system on workflow. Data from site 1 will be used to develop improvements in the eMM and implemented at site 2, where the SWCRCT design will be repeated (stage 2).

ETHICS AND DISSEMINATION

The research has been approved by the Human Research Ethics Committee of the Sydney Children's Hospitals Network and Macquarie University. Results will be reported through academic journals and seminar and conference presentations.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ANZCTR) 370325.

Filling gaps in notification data: a model-based approach applied to travel related campylobacteriosis cases in New Zealand

Background

Data containing notified cases of disease are often compromised by incomplete or partial information related to individual cases. In an effort to enhance the value of information from enteric disease notifications in New Zealand, this study explored the use of Bayesian and Multiple Imputation (MI) models to fill risk factor data gaps. As a test case, overseas travel as a risk factor for infection with campylobacteriosis has been examined.

Methods

Two methods, namely Bayesian Specification (BAS) and Multiple Imputation (MI), were compared regarding predictive performance for various levels of artificially induced missingness of overseas travel status in campylobacteriosis notification data. Predictive performance of the models was assessed through the Brier Score, the Area Under the ROC Curve and the Percent Bias of regression coefficients. Finally, the best model was selected and applied to predict missing overseas travel status of campylobacteriosis notifications.

Results

While no difference was observed in the predictive performance of the BAS and MI methods at a lower rate of missingness (<10 %), but the BAS approach performed better than MI at a higher rate of missingness (50 %, 65 %, 80 %). The estimated proportion (95 % Credibility Intervals) of travel related cases was greatest in highly urban District Health Boards (DHBs) in Counties Manukau, Auckland and Waitemata, at 0.37 (0.12, 0.57), 0.33 (0.13, 0.55) and 0.28 (0.10, 0.49), whereas the lowest proportion was estimated for more rural West Coast, Northland and Tairawhiti DHBs at 0.02 (0.01, 0.05), 0.03 (0.01, 0.08) and 0.04 (0.01, 0.06), respectively. The national rate of travel related campylobacteriosis cases was estimated at 0.16 (0.02, 0.48).

Conclusion

The use of BAS offers a flexible approach to data augmentation particularly when the missing rate is very high and when the Missing At Random (MAR) assumption holds. High rates of travel associated cases in urban regions of New Zealand predicted by this approach are plausible given the high rate of travel in these regions, including destinations with higher risk of infection. The added advantage of using a Bayesian approach is that the model’s prediction can be improved whenever new information becomes available.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1784-8) contains supplementary material, which is available to authorized users.

Mechanical properties of the tumor stromal microenvironment probed in vitro and ex vivo by in situ-calibrated optical trap-based active microrheology

One of the hallmarks of the malignant transformation of epithelial tissue is the modulation of stromal components of the microenvironment. In particular, aberrant extracellular matrix (ECM) remodeling and stiffening enhances tumor growth and survival and promotes metastasis. Type I collagen is one of the major ECM components. It serves as a scaffold protein in the stroma contributing to the tissue's mechanical properties, imparting tensile strength and rigidity to tissues such as those of the skin, tendons, and lungs. Here we investigate the effects of intrinsic spatial heterogeneities due to fibrillar architecture, pore size and ligand density on the microscale and bulk mechanical properties of the ECM. Type I collagen hydrogels with topologies tuned by polymerization temperature and concentration to mimic physico-chemical properties of a normal tissue and tumor microenvironment were measured by in situ-calibrated Active Microrheology by Optical Trapping revealing significantly different microscale complex shear moduli at Hz-kHz frequencies and two orders of magnitude of strain amplitude that we compared to data from bulk rheology measurements. Access to higher frequencies enabled observation of transitions from elastic to viscous behavior that occur at ~200Hz to 2750Hz, which largely was dependent on tissue architecture well outside the dynamic range of instrument acquisition possible with SAOS bulk rheology. We determined that mouse melanoma tumors and human breast tumors displayed complex moduli ~5-1000 Pa, increasing with frequency and displaying a nonlinear stress-strain response. Thus, we show the feasibility of a mechanical biopsy in efforts to provide a diagnostic tool to aid in the design of therapeutics complementary to those based on standard histopathology.

Abstract LB-281: Elucidating potential therapeutic targets in a model of Pten/Tp53 null prostate cancer using high-throughput screening technology

Prostate cancer (PCa) demonstrates significant intra and inter tumor heterogeneity, similar to many other solid tumors. The “gold standard” of therapy for metastatic prostate cancer is androgen deprivation therapy (ADT). Although ADT is initially effective, acquired resistance, termed castration resistant prostate cancer (CRPC), almost always occurs. It is believed that development of CRPC is governed by both intrinsically resistant progenitor cells and by acquired genomic mutations. Clinically advanced CRPC tumors often display loss of PTEN (40%) and aberrations in TP53 (50%), the presence of which in primary prostate cancer are associated with poor clinical prognosis. Our goal is to identify novel targeted therapies against progenitor cells harboring Pten/Tp53 mutations.

To enable high throughput screening, we derived multiple cell lines from a PB-Cre4 Ptenfl/fl;Tp53fl/fl mouse model before (intact) and after (castrate) castration. The RNA-seq analyses of the 8 resultant cell lines revealed distinct clustering of intact and castrate lines as well as patterns of expression characteristic of progenitor cells. Cell lineage marker analysis showed strong KRT8 and minimal KRT5 expression. Using these 8 distinct luminal cell lines, we performed the mechanism interrogation plate (MIPe) screen, a high throughput 1,912 compound screening assay at the National Center for Advancing Translational Science (NCATS). Post-screen informatics data processing and subsequent analysis sorted out compounds that displayed strong activity (1.1 and 1.2 curve class). Multiple compounds were unique to each cell line, however, no difference in sensitivity between the two groups of intact and castrate cell types was observed. Grouping of intact and castrate cell lines together as one population identified a diverse array of 235 compounds (12% of MIPe library) with robust activity against most of the cell lines. Some of these compounds are redundant for specific targets that are key regulators of a multitude of signaling pathways, such as the heat shock protein HSP90AB1, which was targeted by 11 different compounds. In contrast, other targets, like BIRC5, were potently targeted by only one compound. A majority of the 235 compounds targeted components of signaling pathways important in PCa, including: 28 compounds targeting PI3K/AKT/mTOR signaling (AKT1, PIK3CA, mTORc 1/2), 13 compounds targeting cell cycle regulators (CDK1, CDK4), 13 compounds targeting DNA repair and replication (CHEK1, TOP2A), 6 compounds targeting NFKB signaling (IKBKB,ITK) and 5 compounds targeting MAPK signaling (MAPK8, MAP2K1). Using high throughput screening technology to sort for compounds based on potency and activity identified clinically and biologically relevant therapeutic applications for existing compounds in a novel context, Pten/Tp53 null PCa progenitor cells.

Citation Format: Keith H. Jansson, John K. Simmons, Caitlyn Fuller, Supreet Agarwal, Paul G. Hynes, Lei Fang, Ross Lake, Jacob Cawley, Lauren Stahl, Xiaohu Zhang, Rajarshi Guha, Craig Thomas, Kathleen Kelly. Elucidating potential therapeutic targets in a model of Pten/Tp53 null prostate cancer using high-throughput screening technology. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-281.

Abstract LB-276: The identification and characterization of prostate adenocarcinoma tumor initiating cells

Primary prostate cancer is typically of luminal phenotype. However, little is known about the stem/progenitor properties of transformed luminal tumor cells as they fail to survive in culture. Using the organoid culture methodology, we show two distinct luminal progenitors in aggressive Pten/Tp53-null mouse model of prostate cancer. Not only did tumors contain previously described multipotent progenitors, but also a major population of committed luminal progenitors. The distinction between committed luminal and multipotent organoids was also evident in subcutaneous grafts as tumors of adenocarcinoma or multilineage histological phenotypes were observed, respectively. Moreover, using organoids we show that the self-renewing capacity of luminal-committed progenitors is a tumor-specific property, absent in benign luminal cells. Further, a significant fraction of luminal progenitors displayed resistance to in vivo castration as well as to androgen receptor inhibition ex vivo. Importantly, 3D organoid techniques have allowed us to relate our findings in humans as we can successfully grow similar luminal tumor populations from patient derived xenografts (PDXs) models of prostate cancer. In all, these data reveal two distinct luminal tumorigenic populations in mouse models of prostate cancer, providing insight into luminal tumor initiating cells in prostate cancer that can also influence response to therapy.

Citation Format: Supreet Agarwal, Paul Hynes, Ross Lake, Lei Fang, Heather Tillman, Mike Beshiri, Keith Jansson, Wouter Karthaus, Philip Iaquinta, Charles Sawyers, Kathleen Kelly. The identification and characterization of prostate adenocarcinoma tumor initiating cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-276.

Capturing Accurate and Useful Information on Medication-Related Telenursing Triage Calls

Registered nurses providing telenursing triage and advice services record information on the medication related calls they handle. However the quality and consistency of these data were rarely examined. Our aim was to examine medication related calls made to the healthdirect advice service in November 2014, to assess their basic characteristics and how the data entry format influenced information collected and data consistency. Registered nurses selected the patient question type from a range of categories, and entered the medications involved in a free text field. Medication names were manually extracted from the free text fields. We also compared the selected patient question type with the free text description of the call, in order to gauge data consistency. Results showed that nurses provided patients with advice on medication-related queries in a timely matter (the median call duration of 9 minutes). From 1835 calls, we were able to identify and classify 2156 medications into 384 generic names. However, in 204 cases (11.2% of calls) no medication name was entered. A further 308 (15.0%) of the medication names entered were not identifiable. When we compared the selected patient question with the free text description of calls, we found that these were consistent in 63.27% of cases. Telenursing and triage advice services provide a valuable resource to the public with quick and easily accessible advice. To support nurses provide quality services and record accurate information about the queries, appropriate data entry format and design would be beneficial.

Vital signs monitoring and nurse-patient interaction: A qualitative observational study of hospital practice

BACKGROUND

High profile safety failures have demonstrated that recognising early warning signs of clinical and physiological deterioration can prevent or reduce harm resulting from serious adverse events. Early warning scoring systems are now routinely used in many places to detect and escalate deteriorating patients. Timely and accurate vital signs monitoring are critical for ensuring patient safety through providing data for early warning scoring systems, but little is known about current monitoring practices.

OBJECTIVE

To establish a profile of nurses' vital signs monitoring practices, related dialogue, and adherence to health service protocol in New South Wales, Australia.

METHODS

Direct observations of nurses' working practices were conducted in two wards. The observations focused on times of the day when vital signs were generally measured. Patient interactions were recorded if occurring any time during the observation periods. Participants (n=42) included nursing staff on one chronic disease medical and one acute surgical ward in a large urban teaching hospital in New South Wales.

RESULTS

We observed 441 patient interactions. Measurement of vital signs occurred in 52% of interactions. The minimum five vital signs measures required by New South Wales Health policy were taken in only 6-21% of instances of vital signs monitoring. Vital signs were documented immediately on 93% of vitals-taking occasions and documented according to the policy in the patient's chart on 89% of these occasions. Nurse-patient interactions were initiated for the purpose of taking vital signs in 49% of interactions, with nurse-patient discourse observed during 88% of all interactions. Nurse-patient dialogue led to additional care being provided to patients in 12% of interactions.

CONCLUSION

The selection of appropriate vital signs measured and responses to these appears to rely on nurses' clinical judgement or time availability rather than on policy-mandated frequency. The prevalence of incomplete sets of vital signs may limit identification of deteriorating patients. The findings from this study present an important baseline profile against which to evaluate the impact of introducing continuous monitoring approaches on current hospital practice.

Identification of Different Classes of Luminal Progenitor Cells within Prostate Tumors

Primary prostate cancer almost always has a luminal phenotype. However, little is known about the stem/progenitor properties of transformed cells within tumors. Using the aggressive Pten/Tp53-null mouse model of prostate cancer, we show that two classes of luminal progenitors exist within a tumor. Not only did tumors contain previously described multipotent progenitors, but also a major population of committed luminal progenitors. Luminal cells, sorted directly from tumors or grown as organoids, initiated tumors of adenocarcinoma or multilineage histological phenotypes, which is consistent with luminal and multipotent differentiation potentials, respectively. Moreover, using organoids we show that the ability of luminal-committed progenitors to self-renew is a tumor-specific property, absent in benign luminal cells. Finally, a significant fraction of luminal progenitors survived in vivo castration. In all, these data reveal two luminal tumor populations with different stem/progenitor cell capacities, providing insight into prostate cancer cells that initiate tumors and can influence treatment response.

AR-regulated TWEAK-FN14 pathway promotes prostate cancer bone metastasis

The recurrence of prostate cancer metastases to bone after androgen deprivation therapy is a major clinical challenge. We identified FN14 (TNFRSF12A), a TNF receptor family member, as a factor that promotes prostate cancer bone metastasis. In experimental models, depletion of FN14 inhibited bone metastasis, and FN14 could be functionally reconstituted with IKKβ-dependent, NFκB signaling activation. In human prostate cancer, upregulated FN14 expression was observed in more than half of metastatic samples. In addition, FN14 expression was correlated inversely with androgen receptor (AR) signaling output in clinical samples. Consistent with this, AR binding to the FN14 enhancer decreased expression. We show here that FN14 may be a survival factor in low AR output prostate cancer cells. Our results define one upstream mechanism, via FN14 signaling, through which the NFκB pathway contributes to prostate cancer metastasis and suggest FN14 as a candidate therapeutic and imaging target for castrate-resistant prostate cancers.

Understanding the burden of disease in Nepal: a call for local evidence

The burden of disease, most commonly expressed in terms of Disability-Adjusted Life Years, has become a crucial component in decision making processes within the health sector. In Nepal, however, burden of disease estimates are scarce and lack representativeness. To improve our understanding of the burden of disease in Nepal and thereby increase the efficiency of health policies, there is an urgent need to strengthen the local evidence base. All relevant stakeholders should therefore collaborate to generate new data, improve existing data generation mechanisms, make generated data available, and optimize the use of available data.

Abstract 2708: The TWEAK-FN14 pathway promotes prostate cancer bone metastasis through the NFκB pathway

Advanced prostate cancer is highly associated with castration resistance and the development of bone metastases. Understanding the mechanisms contributing to prostate cancer bone metastasis is needed in order to develop novel therapeutic agents. NFκB signaling has been implicated in prostate cancer progression. The Tweak-Fn14 axis, which activates both canonical and non-canonical NFκB pathways, has been shown to be up-regulated in many cancer types. However, the role of the Tweak-Fn14 signaling in prostate cancer progression has not been investigated. In this study, we show that oncogenic Ras transformation of the AR negative, DU145 cell line led to the acquisition of bone metastatic capability and associated increased expression of TWEAK and FN14. Knocking down FN14 using shRNAs, as well as blocking the NFκB pathway using an IKBα super repressor, in DU145/Rasb1 cells, significantly inhibited bone metastasis and improved survival. This inhibitory effect of FN14shRNA was fully rescued by activating the NFκB canonical pathway, but not the NFκB non-canonical pathway. FN14 expression is also high in the bone metastatic, AR negative prostate cancer PC3 cell line. Similarly, knocking-down FN14 in PC3 cells inhibited bone metastatic capacity following intracardiac inoculation in a xenograft model. TWEAK and FN14 are relatively low or undetectable in AR positive prostate cancer cell lines including Lncap and 22RV1. AR binding was detected in both TWEAK and FN14 promoters as determined by chromatin immunoprecipitation analysis in Lncap. Reporter assays demonstrated that AR binding inhibited FN14 and TWEAK transcription. The above experimental models were further supported by analyses of publically available expression data sets for clinical prostate cancer samples that showed FN14 expression was inversely correlated with AR gene expression signatures. In addition, individual FN14 RNA mean expression was higher in clinical metastasis of castrate (n=11) as compared to non-castrate (n=8) patients. We propose that down-regulation of AR activity under castrate conditions may lead to increased FN14 expression and NFκB activation, which provides a survival benefit for prostate cancer cells associated with disease progression. Therefore, targeting the TWEAK-FN14 pathway in prostate cancer patients provides potential, new preventive and therapeutic approaches.

Citation Format: Juan Juan Yin, Yen-Nien Liu, Ben Barrett, Lei Fang, Ross Lake, Orla Casey, Heather Tillman, Yvona Ward, Kathleen Kelly. The TWEAK-FN14 pathway promotes prostate cancer bone metastasis through the NFκB pathway. [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 2708. doi:10.1158/1538-7445.AM2013-2708

TMPRSS2- driven ERG expression in vivo increases self-renewal and maintains expression in a castration resistant subpopulation

Genomic rearrangements commonly occur in many types of cancers and often initiate or alter the progression of disease. Here we describe an in vivo mouse model that recapitulates the most frequent rearrangement in prostate cancer, the fusion of the promoter region of TMPRSS2 with the coding region of the transcription factor, ERG. A recombinant bacterial artificial chromosome including an extended TMPRSS2 promoter driving genomic ERG was constructed and used for transgenesis in mice. TMPRSS2-ERG expression was evaluated in tissue sections and FACS-fractionated prostate cell populations. In addition to the anticipated expression in luminal cells, TMPRSS2-ERG was similarly expressed in the Sca-1^hi/EpCAM⁺ basal/progenitor fraction, where expanded numbers of clonogenic self-renewing progenitors were found, as assayed by in vitro sphere formation. These clonogenic cells increased intrinsic self renewal in subsequent generations. In addition, ERG dependent self-renewal and invasion in vitro was demonstrated in prostate cell lines derived from the model. Clinical studies have suggested that the TMPRSS2-ERG translocation occurs early in prostate cancer development. In the model described here, the presence of the TMPRSS2-ERG fusion alone was not transforming but synergized with heterozygous Pten deletion to promote PIN. Taken together, these data suggest that one function of TMPRSS2-ERG is the expansion of self-renewing cells, which may serve as targets for subsequent mutations. Primary prostate epithelial cells demonstrated increased post transcriptional turnover of ERG compared to the TMPRSS2-ERG positive VCaP cell line, originally isolated from a prostate cancer metastasis. Finally, we determined that TMPRSS2-ERG expression occurred in both castration-sensitive and resistant prostate epithelial subpopulations, suggesting the existence of androgen-independent mechanisms of TMPRSS2 expression in prostate epithelium.

Self-renewing Pten-/- TP53-/- protospheres produce metastatic adenocarcinoma cell lines with multipotent progenitor activity

Prostate cancers of luminal adenocarcinoma histology display a range of clinical behaviors. Although most prostate cancers are slow-growing and indolent, a proportion is aggressive, developing metastasis and resistance to androgen deprivation treatment. One hypothesis is that a portion of aggressive cancers initiate from stem-like, androgen-independent tumor-propagating cells. Here we demonstrate the in vitro creation of a mouse cell line, selected for growth as self-renewing stem/progenitor cells, which manifests many in vivo properties of aggressive prostate cancer. Normal mouse prostate epithelium containing floxed Pten and TP53 alleles was subjected to CRE-mediated deletion in vitro followed by serial propagation as protospheres. A polyclonal cell line was established from dissociated protospheres and subsequently a clonal daughter line was derived. Both lines demonstrate a mature luminal phenotype in vitro. The established lines contain a stable minor population of progenitor cells with protosphere-forming ability and multi-lineage differentiation capacity. Both lines formed orthotopic adenocarcinoma tumors with metastatic potential to lung. Intracardiac inoculation resulted in brain and lung metastasis, while intra-tibial injection induced osteoblastic bone formation, recapitulating the bone metastatic phenotype of human prostate cancer. The cells showed androgen receptor dependent growth in vitro. Importantly, in vivo, the deprivation of androgens from established orthotopic tumors resulted in tumor regression and eventually castration-resistant growth. These data suggest that transformed prostate progenitor cells preferentially differentiate toward luminal cells and recapitulate many characteristics of the human disease.

LPA receptor heterodimerizes with CD97 to amplify LPA-initiated RHO-dependent signaling and invasion in prostate cancer cells

CD97, an adhesion-linked G-protein-coupled receptor (GPCR), is induced in multiple epithelial cancer lineages. We address here the signaling properties and the functional significance of CD97 expression in prostate cancer. Our findings show that CD97 signals through Gα12/13 to increase RHO-GTP levels. CD97 functioned to mediate invasion in prostate cancer cells, at least in part, by associating with lysophosphatidic acid receptor 1 (LPAR1), leading to enhanced LPA-dependent RHO and extracellular signal-regulated kinase activation. Consistent with its role in invasion, depletion of CD97 in PC3 cells resulted in decreased bone metastasis without affecting subcutaneous tumor growth. Furthermore, CD97 heterodimerized and functionally synergized with LPAR1, a GPCR implicated in cancer progression. We also found that CD97 and LPAR expression were significantly correlated in clinical prostate cancer specimens. Taken together, these findings support the investigation of CD97 as a potential therapeutic cancer target.

Improved antibacterial host defense and altered peripheral granulocyte homeostasis in mice lacking the adhesion class G protein receptor CD97

CD97 is a member of the adhesion family of G protein-coupled receptors. Alternatively spliced forms of CD97 bind integrins alpha5beta1 and alphavbeta3, decay accelerating factor, or dermatan sulfate. CD97 is expressed on myeloid cells at high levels and a variety of other cell types at lower levels. Little is known about the physiological function of CD97. To begin dissecting the function of CD97, we evaluated the immune response of CD97 null mice to systemic infection by Listeria monocytogenes. CD97 null mice were significantly more resistant to listeriosis than matched wild-type mice. A major determinant of the difference in survival appeared to be the comparatively more robust accumulation of granulocytes in the blood and in infected livers of CD97 null mice within 18 h of inoculation, correlating with a decrease in the number of bacteria. CD97 null mice also displayed a mild granulocytosis in the nonchallenged state. Because there is a strong suggestion that CD97 functions in an adhesive capacity, we examined the migratory properties of granulocytes in CD97 null mice. In chimeric animals, CD97 null and wild-type granulocytes migrated similarly, as determined by inflammation-induced emigration from the bone marrow and accumulation in the peritoneum. Granulocyte development in the bone marrow of CD97 null mice was comparable to that of wild-type mice, and CD97 deficiency did not appear to stimulate granulocytosis secondary to peripheral inflammation and resultant granulocyte colony-stimulating factor induction, unlike various other models of adhesion deficiencies. Our results suggest that CD97 plays a role in peripheral granulocyte homeostasis.

Remediation of bromate-contaminated groundwater in an ex situ fixed-film bioreactor

Use of a pilot-scale fixed-film bioreactor was investigated for remediation of bromate contamination within groundwater. Bromate reduction with stoichiometric production of bromide was observed, providing supporting evidence for complete reduction of bromate with no production of stable intermediates. Reduction of 87-90% bromate from an influent concentration of 1.1 mg L(-1) was observed with retention times of 40-80 h. Lower retention times led to decreases in bromate reduction capability, with 11.5% removal at a 10 h retention time. Nitrate reduction of 76-99% from a 30.7 mg L(-1) as NO(3)(-) influent was observed at retention times of 10-80 h, although an increase in nitrite production to 2.7 mg L(-1) occurred with a 10 h retention time. Backwashing was not required, with the large plastic packing media able to accommodate biomass accumulation without decreases in operational efficiency. This study has provided proof of concept and demonstrated the potential of biological bromate reduction by fixed-film processes for remediation of a bromate contaminated groundwater source.

Reduction of bromate in groundwater with an ex situ suspended growth bioreactor

A potential remediation technique for groundwater contaminated by bromate has been investigated, utilising biological bromate reduction to bromide by augmentation of indigenous microbial populations. This technique, involving addition of a carbon source to contaminated groundwater, is being developed as an ex-situ methodology analogous to commercial denitrification systems, but may also have in-situ applications. Trials have focussed on a laboratory-scale anaerobic suspended growth chemostat system, investigating glucose addition to real groundwater supplies. Steady states for a range of glucose and bromate concentrations demonstrated bromate reduction up to 700 microgl(-1) (50% of 1400 microgl(-1) influent) with glucose excess (above 52 mgl(-1)), but specific reduction rates (up to 2.83 micromol Br.g dry wt(-1) hr(-1) for 1400 microgl(-1) bromate influent) were low compared to denitrification (up to 305 micromol N g dry wt(-1) hr(-1)). More recent enrichment trials have demonstrated reduction of 32 mgl(-1) bromate within a 40 hour residence time with specific reduction rates of up to 160.48 micromol Br.g dry wt(-1) hr(-1), suggesting the presence of high rate bromate reducing bacterial strains.

CD97, an adhesion receptor on inflammatory cells, stimulates angiogenesis through binding integrin counterreceptors on endothelial cells

CD97, a membrane protein expressed at high levels on inflammatory cells and some carcinomas, is a member of the adhesion G protein-coupled receptor family, whose members have bipartite structures consisting of an extracellular peptide containing adhesion motifs noncovalently coupled to a class B 7-transmembrane domain. CD97alpha, the extracellular domain of CD97, contains 3 to 5 fibrillin class 1 epidermal growth factor (EGF)-like repeats, an Arg-Gly-Asp (RGD) tripeptide, and a mucin stalk. We show here that CD97alpha promotes angiogenesis in vivo as demonstrated with purified protein in a directed in vivo angiogenesis assay (DIVAA) and by enhanced vascularization of developing tumors expressing CD97. These data suggest that CD97 can contribute to angiogenesis associated with inflammation and tumor progression. Strong integrin alpha5beta1 interactions with CD97 have been identified, but alpha v beta3 also contributes to cell attachment. Furthermore, soluble CD97 acts as a potent chemoattractant for migration and invasion of human umbilical vein endothelial cells (HUVECs), and this function is integrin dependent. CD97 EGF-like repeat 4 is known to bind chondroitin sulfate. It was found that coengagement of alpha5beta1 and chondroitotin sulfate proteoglycan by CD97 synergistically initiates endothelial cell invasion. Integrin alpha5beta1 is the first high-affinity cellular counterreceptor that has been identified for a member within this family of adhesion receptors.

Postcibal gastric emptying of pancreatin pellets: effects of dose and meal oil

To treat pancreatic exocrine insufficiency, physicians often prescribe enterically coated pellets of pancreatin to be taken with meals. The pellets are only partially effective in correcting the digestion and absorption of fat. We sought to determine in normal subjects whether emptying of pellets from the postcibal stomach was dose-related and whether the gastric emptying of lipophilic Creon-20 or Pancrease was altered by the presence or the absence of oil in a meal. Gastric emptying of pellets surface-labeled with 113mIn or 99mTc was followed with a gamma camera for 300 min after isocaloric meals. From our observations, we concluded that gastric emptying of 0.28-1.12 g of 1-mm or 2-mm pellets was dose-related (P < 0.01) and emptying of neither Creon-20 nor Pancrease was much affected by oil in the meal.

MAML1, a human homologue of Drosophila mastermind, is a transcriptional co-activator for NOTCH receptors

Notch receptors are involved in cell-fate determination in organisms as diverse as flies, frogs and humans. In Drosophila melanogaster , loss-of-function mutations of Notch produce a 'neurogenic' phenotype in which cells destined to become epidermis switch fate and differentiate to neural cells. Upon ligand activation, the intracellular domain of Notch (ICN) translocates to the nucleus, and interacts directly with the DNA-binding protein Suppressor of hairless (Su(H)) in flies, or recombination signal binding protein Jkappa (RBP-Jkappa) in mammals, to activate gene transcription. But the precise mechanisms of Notch-induced gene expression are not completely understood. The gene mastermind has been identified in multiple genetic screens for modifiers of Notch mutations in Drosophila. Here we clone MAML1, a human homologue of the Drosophila gene Mastermind, and show that it encodes a protein of 130 kD localizing to nuclear bodies. MAML1 binds to the ankyrin repeat domain of all four mammalian NOTCH receptors, forms a DNA-binding complex with ICN and RBP-Jkappa, and amplifies NOTCH-induced transcription of HES1. These studies provide a molecular mechanism to explain the genetic links between mastermind and Notch in Drosophila and indicate that MAML1 functions as a transcriptional co-activator for NOTCH signalling.

Increased regional cerebral perfusion by 99mTc hexamethyl propylene amine oxime single photon emission computed tomography in post-traumatic stress disorder

OBJECTIVE

Because of the treatment resistance and chronic affective lability of many post-traumatic stress disorder (PTSD) patients and the hypothesized association of these behaviors with temporal and limbic structures, a study was conducted to determine whether these patients would exhibit alterations in regional cerebral perfusion in the temporal and limbic regions compared with age-matched normal volunteers at rest.

METHOD

We studied 17 patients using 99mTc hexamethyl propylene amine oxime single photon emission computed tomography. Seven of the patients were on a selective serotonin reuptake inhibitor, five were on a tricyclic antidepressant, and five were on no medication at the time of the study. Patients were compared with eight age-matched normal controls.

RESULTS

All PTSD patients showed a relative increase in regional cerebral perfusion in the anterior and posterior cingulate regions bilaterally, the right temporal and parietal regions, the right caudate/putamen region, and the left orbital and hippocampal regions compared with the control group. When the group of PTSD patients who were free of medication were compared with the control group, increased regional cerebral perfusion was found in the right and left caudate/putamen regions and the right orbital and anterior cingulate cortex bilaterally.

CONCLUSIONS

PTSD is associated with increased regional blood flow in limbic areas and the right temporal and parietal cortex compared with age-matched normal volunteers.

Gastric emptying of indigestible versus digestible oils and solid fats in normal humans

Recent scintigraphic studies indicate that lipolytic products in the small intestine do not inhibit gastric emptying of fat as potently as previously suggested by studies that compared a liquid indigestible oil with a solid digestible fat. The older studies left open the confounding possibility that solid fats emptied differently than liquid oil. We studied eight normal subjects who ingested four meals in which fat was (1) liquid, digestible Crisco oil, (2) liquid, indigestible sucrose polyester oil, (3) digestible, solid Crisco, and (4) indigestible, solid olestra. Fats were labeled with iodine-123, and their gastric emptying was followed with a gamma camera. Indigestible fats (whether liquid or solid) emptied consistently faster than digestible fats (P < 0.005), although differences were small. Solid fats emptied about as rapidly as oils in the first hour; but more slowly thereafter (P < 0.01). A comparison of present scintigraphic with older studies suggested that solid fats were not well tracked by duodenal, marker-perfusion techniques, which misled previous investigators.

Cytokine gene therapy or infusion as treatment for solid human cancer

In the induction of tissue-directed immune responses, cytokines tend to be released within the affected tissues. We used two strategies to expose tumor tissues to continuous high levels of cytokines: First, a vaccinia interleukin (IL)2 recombinant was injected directly intratumorally 3-weekly at 10(7) pfus/dose in six patients with the solid tumor malignant mesothelioma (MM). No virus excretion was detectable. At each cycle vaccinia-IL-2 mRNA (SQ [semi-quantitative] reverse transcription polymerase chain reaction) was maximal 24-72 h following injection reduced at 8 days and faded by 21 days. No tumor regression occurred. Second, based on the success of granulocyte macrophage colony-stimulating factor (GM-CSF) in gene transfer experiments, we conducted a study using continuous intratumoral GM-CSF infusion in eight patients with MM using a portable pump at doses of 10 micro/cg/24 h over 8 weeks. Systemic neutrophil agglutination and local catheter-related difficulties occurred. Two patients demonstrated tumor necrosis, one of whom had a marked progressive mononuclear cell infiltration of the tumor associated with a partial response (>50% reduction in tumor area). Murine studies using our MM model in CBA and BALB/C mice have demonstrated that B7-1 and allo-class I transfections induce strong tumor-specific cytotoxic T lymphocyte responses: GM-CSF, IL-12, and IL-2 induced mixed nonspecific plus specific responses, whereas B7-2 and class II transfections were not effective. We conclude that increased intratumoral cytokine concentrations can be generated using both gene transfer and cytokine infusion approaches; however, both have their limitations and, at this stage, have not produced dramatic antitumor effects in humans.

Mismatch of duodenal deliveries of dietary fat and pancreatin from enterically coated microspheres

Gastric emptying of dietary fat is affected by both chemical and physical factors; but when ingested as a free oil or an aqueous emulsion, fat may empty most rapidly immediately after the meal. In contrast, gastric transit of 1- to 3-mm spheres (like those of enterically coated pancreatins) is known to vary inversely with sphere diameter; and spheres leave the stomach initially slowly, if their diameter is > or = 1.6 mm. Our objective was to determine whether 2-mm microspheres of Pancrease would empty much more slowly than free or emulsified oil and whether 1.2-mm microspheres of Creon would empty as fast as free oil. We used a gamma camera to track the concurrent gastric emptying of 123I-labeled oil and 113mIn-labeled spheres of Pancrease or Creon in pancreatic-insufficient subjects with cystic fibrosis who ingested 20 g of free oil in spaghetti meals or 20 g of oil emulsified in a milk meal. We found that either type of oil emptied rapidly initially but slowed later, whereas either dosage form emptied slowly initially but rapidly later. Unexpectedly, the smaller spheres of Creon emptied about the same as Pancrease did after the spaghetti meal. For example, 50% of oil but < 25% of either dosage form had left the stomach by 90 min after the meals. Both dosage forms were lipophilic, forming aggregates in vitro. We concluded that the gastric emptying of either dosage form frequently lagged behind the emptying of oil from ordinary meals. We speculated that the similar transits of the 1.2-mm Creon and the 2-mm Pancrease resulted from aggregation of these microspheres in the presence of free oil.