Osteoclast-like stromal giant cells in breast cancer likely belong to the spectrum of immunosuppressive tumor-associated macrophages

Background: Breast cancer with osteoclast-like stromal giant cells (OSGC) is an exceedingly rare morphological pattern of invasive breast carcinoma. The tumor immune microenvironment (TIME) of these tumors is populated by OSGC, which resemble osteoclasts and show a histiocytic-like immunophenotype. Their role in breast cancer is unknown. The osteoclast maturation in the bone is regulated by the expression of cytokines that are also present in the TIME of tumors and in breast cancer tumor-associated macrophages (TAMs). TAMs-mediated anti-tumor immune pathways are regulated by miRNAs akin to osteoclast homeostasis. Here, we sought to characterize the different cellular compartments of breast cancers with OSGC and investigate the similarities of OSGC with tumor and TIME in terms of morphology, protein, and miRNA expression, specifically emphasizing on monocytic signatures.

Methods and Results: Six breast cancers with OSGC were included. Tumor-infiltrating lymphocytes (TILs) and TAMs were separately quantified. The different cellular populations (i.e., normal epithelium, cancer cells, and OSGC) were isolated from tissue sections by laser-assisted microdissection. After RNA purification, 752 miRNAs were analyzed using a TaqMan Advanced miRNA Low-Density Array for all samples. Differentially expressed miRNAs were identified by computing the fold change (log2Ratio) using the Kolmogorov-Smirnov test and p values were corrected for multiple comparisons using the false discovery rate (FDR) approach. As a similarity analysis among samples, we used the Pearson test. The association between pairs of variables was investigated using Fisher exact test. Classical and non-classical monocyte miRNA signatures were finally applied. All OSGC displayed CD68 expression, TILs (range, 45–85%) and high TAMs (range, 35–75%). Regarding the global miRNAs profile, OSGC was more similar to cancer cells than to non-neoplastic ones. Shared deregulation of miR-143-3p, miR-195-5p, miR-181a-5p, and miR-181b-5p was observed between OSGC and cancer cells. The monocyte-associated miR-29a-3p and miR-21-3p were dysregulated in OSGCs compared with non-neoplastic or breast cancer tissues.

Conclusion: Breast cancers with OSGC have an activated TIME. Shared epigenetic events occur during the ontogenesis of breast cancer cells and OSGC but the innumophenotype and miRNA profiles of the different cellular compartmens suggest that OSGC likely belong to the spectrum of M2 TAMs.

Abstract 2350: Foxj1 is a new master regulator of activated PI3K pathway pancreatic cancer

Background: Pancreatic ductal adenocarcinoma (PDAC) is predicted to become the second leading cause of cancer mortality within a decade with overall 5-year survival of 8% for all stages combined. Currently, it is well documented that mechanisms driving PDAC progression involve epigenetic and transcriptional rewiring. Here we combined assay for transposase-accessible chromatin using sequencing (ATAC-seq) and enrichment for H3K27 acetylation chromatin immunoprecipitation (H3K27ac ChIP-seq) measures to explore the epigenetic landscape of different mouse primary pancreatic tumor (PPT) cell lines.

Methods: Kras-driven (n=36) and PI3K-driven PPT cell lines (n=9) were cultured in DMEM medium (Gibco). DNA was extracted using manufacture protocols (Qiagen, MinElute PCR Purification Kit) then DNA libraries and high-throughput sequencing were performed. Bioinformatics analysis (ROSE2 Python script) was conducted on H3k27ac ChIP-seq data to define super-enhancer (SEs) and SE-associated genes. Then, ATAC-seq data was explored using Coltron Python package to distinguish enriched Transcription Factor (TF) motifs into SEs. Transcriptomic data was used to slim down the list of potential cis-regulatory elements. We developed knockout (ko) PPT cell lines using CRISPR/CAS9 gene editing method to better characterize the role of Foxj1 as a novel potential master regulator in pancreatic cancer. Lastly, immunohistochemistry (IHC) staining for FOXJ1 was conducted on human PDAC cohort.

Results: By k-means clustering, we identified 463 SE-associated genes. Many of them are associated with Kras-driven (epithelial or mesenchymal) or PI3K-driven cell lines exclusively. Surprisingly, we found Foxj1 as SE-associated TF exclusively in PI3K-driven PPT cell lines. Consistent with the epigenetic data, transcriptomic analysis confirmed higher expression of Foxj1 in PI3K-driven PPT cell lines. Then, RNA-seq data revealed downregulation of predicted Foxj1 target genes and enhanced EMT and Wnt/β-catenin signatures in Foxj1 ko cells. These data suggest that epithelial properties of PDAC cells are stabilized by Foxj1 activity. Consistent with these results we detect a higher potential of TGFβ treatment to induce mesenchymal features in Foxj1 ko cells. Furthermore, overexpression of β-catenin protein was confirmed by immunofluorescence. Enhanced Wnt/β-catenin signaling could be responsible for the higher proliferation of Foxj1 ko cells as revealed by proliferation assay. Finally, we investigated FOXJ1 protein level in our PDAC human cohort. Interestingly, we found high nuclear FOXJ1 expression in 23% of cases which is linked with better overall survival.

Conclusions: In summary, our data revealed Foxj1 as a novel PDAC associated TF with the ability to reduce the cancer aggressiveness blocking epithelial to mesenchymal transition and β-catenin activity elucidating the better prognosis into the FOXJ1 high expressed patients.

Citation Format: Andrea Terrasi, Swathi Subramanian, Christine Klement, Sruthi Ramesh, Heike Bollig, Chiara Falcomatà, Katja Steiger, Rupert Öllinger, Dieter Saur, Roland Rad, Maximilian Reichert, Günter Schneider, Gunnar Schotta. Foxj1 is a new master regulator of activated PI3K pathway pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2350.

HDAC2 Facilitates Pancreatic Cancer Metastasis

The mortality of patients with pancreatic ductal adenocarcinoma (PDAC) is strongly associated with metastasis, a multistep process that is incompletely understood in this disease. Although genetic drivers of PDAC metastasis have not been defined, transcriptional and epigenetic rewiring can contribute to the metastatic process. The epigenetic eraser histone deacetylase 2 (HDAC2) has been connected to less differentiated PDAC, but the function of HDAC2 in PDAC has not been comprehensively evaluated. Using genetically defined models, we show that HDAC2 is a cellular fitness factor that controls cell cycle in vitro and metastasis in vivo, particularly in undifferentiated, mesenchymal PDAC cells. Unbiased expression profiling detected a core set of HDAC2-regulated genes. HDAC2 controlled expression of several prosurvival receptor tyrosine kinases connected to mesenchymal PDAC, including PDGFRα, PDGFRβ, and EGFR. The HDAC2-maintained program disabled the tumor-suppressive arm of the TGFβ pathway, explaining impaired metastasis formation of HDAC2-deficient PDAC. These data identify HDAC2 as a tractable player in the PDAC metastatic cascade. The complexity of the function of epigenetic regulators like HDAC2 implicates that an increased understanding of these proteins is needed for implementation of effective epigenetic therapies.

SIGNIFICANCE

HDAC2 has a context-specific role in undifferentiated PDAC and the capacity to disseminate systemically, implicating HDAC2 as targetable protein to prevent metastasis.

An EBC/Plasma miRNA Signature Discriminates Lung Adenocarcinomas From Pleural Mesothelioma and Healthy Controls

Background

Despite significant improvement in screening programs for cancers of the respiratory district, especially in at-risk subjects, early disease detection is still a major issue. In this scenario, new molecular and non-invasive biomarkers are needed to improve early disease diagnosis.

Methods

We profiled the miRNome in exhaled breath condensate (EBC) and plasma samples from fourteen patients affected by lung AdCa, nine healthy subjects. miRNA signatures were then analyzed in another neoplasia of the respiratory district, i.e. pleural mesothelioma (n = 23) and subjects previously exposed to asbestos were used as controls for this cohort (n = 19). Selected miRNAs were analyzed in purified pulmonary neoplastic or normal epithelial and stromal cell subpopulation from AdCa patients. Finally, the plasmatic miRNA signature was analyzed in a publicly available cohort of NSCLC patients for data validation and in silico analysis was performed with predicted miRNA targets using the multiMiR tool and STRING database.

Results

miR-597-5p and miR-1260a are significantly over-expressed in EBC from lung AdCa and are associated with AdCa. Similarly, miR-1260a is also up-regulated in the plasma of AdCa patients together with miR-518f-3p and correlates with presence of lung cancer, whereas let-7f-5p is under-expressed. Analysis of these circulating miRNAs in pleural mesothelioma cases confirmed that up-regulation of miR-518f-3p, -597-5p and -1260a, is specific for lung AdCa. Lastly, quantification of the miRNAs in laser-assisted microdissected lung tissues revealed that miR-518f-3p, 597-5p and miR-1260a are predominantly expressed in tumor epithelial cells. Validation analysis confirmed miR-518f-3p as a possible circulating biomarker of NSCLC. In silico analysis of the potentially modulated biological processes by these three miRNAs, shows that tumor bioenergetics are the most affected pathways.

Conclusions

Overall, our data suggest a 3-miRNAs signature as a non-invasive and accurate biomarker of lung AdCa. This approach could supplement the current screening approaches for early lung cancer diagnosis.

The Oncosuppressors MEN1 and CDC73 Are Involved in lncRNA Deregulation in Human Parathyroid Tumors

A role for long non-coding RNAs (lncRNAs) in endocrine cancer pathogenesis is emerging. However, knowledge regarding their expression pattern, correlation with known genetic defects, and clinical implications in parathyroid tumors is still unclear. Here, we profiled 90 known lncRNAs in a first series of normal (PaN = 2), adenomatous (PAd = 12), and carcinomatous (PCa = 4) parathyroid glands and we confirmed deregulation of 11 lncRNAs using an independent cohort of patients (PaN = 4; PAd = 26; PCa = 9). Expression of lncRNAs was correlated with cytogenetic aberrations, status of genes multiple endocrine neoplasia 1 (MEN1) and cell division cycle 73 (CDC73), or clinical features. Globally, lncRNAs discriminate according to tissue histology. BC200 consistently identifies parathyroid cancers from adenomas and atypical adenomas. Loss-of-heterozygosity (LOH) at chromosomes 1, 11, 15, 21, and 22 significantly impacts expression of lncRNAs in PAds. Silencing of the key parathyroid gene MEN1 modulates the expression of six lncRNAs in primary PAds-derived cultures. Analogous levels of lncRNAs are measured in PAds with the mutation in the MEN1 gene compared with PAds with wild-type MEN1. Similarly, carcinomas with mutated CDC73 differ from PCas with wild-type protein in terms of expression of lncRNAs. PCas harboring CDC73 mutations overexpress BC200 compared to wild-type carcinomas. Overall, these findings shed light on deregulation of lncRNAs in human parathyroid tumors and propose that circuits between lncRNAs and the oncosuppressors MEN1 or CDC73 may have a role in parathyroid tumorigenesis as epigenetic modulators. © 2020 American Society for Bone and Mineral Research (ASBMR).

A miRNome analysis of drug-free manic psychotic bipolar patients versus healthy controls

The lifetime presence of psychotic symptoms is associated with more clinical severity, poorer outcome and biological changes in patients affected by bipolar disorder (BD). Epigenetic mechanisms have been evoked to explain the onset of psychotic symptoms in BD as well as the associated biological changes. The main objective of the present study was to evaluate the expression profiles of circulating microRNAs (miRNAs) in drug-free manic psychotic bipolar patients versus healthy controls (HC), to identify possible non-invasive molecular markers of the disorder. 15 drug-free manic psychotic bipolar patients and 9 HC were enrolled and 800 miRNAs expression profile was measured by Nanostring nCounter technology on plasma samples and validated through qPCR. Overall, twelve miRNAs showed a significantly altered expression between the two groups (p < 0.05). Functional annotation of predicted miRNAs targets by MultiMIR R tool showed repression in bipolar patients of genes with a role in neurodevelopment and neurogenesis, and upregulation of genes involved in metabolism regulation. We identified a signature of circulating miRNA characteristic of manic psychotic bipolar patients, suggesting a possible role in neurodevelopment and metabolic processes regulation.

Free carrier enhanced depletion in ZnO nanorods decorated with bimetallic AuPt nanoclusters

The decoration of semiconductor nanostructures with small metallic clusters usually leads to an improvement of their properties in sensing or catalysis. Bimetallic cluster decoration typically is claimed to be even more effective. Here, we report a detailed investigation of the effects of Au, Pt or AuPt nanocluster decoration of ZnO nanorods on charge transport, photoluminescence and UV sensitivity. ZnO nanorods were synthesized by chemical bath deposition while decoration with small nanoclusters (2-3 nm in size) was achieved by a laser-ablation based cluster beam deposition technology. The structural properties were investigated by scanning electron microscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy and Rutherford backscattering spectrometry, and the optoelectronic properties by current-voltage and photoluminescence measurements. The extent of band bending at the cluster-ZnO interface was quantitatively modeled through numerical simulations. The decoration of ZnO nanorods with monometallic Au or Pt nanoclusters causes a significant depletion of free electrons below the surface, leading to a reduction of UV photoluminescence, an increase of ZnO nanorod dark resistance (up to 200 times) and, as a consequence, an improved sensitivity (up to 6 times) to UV light. These effects are strongly enhanced (up to 450 and 10 times, respectively) when ZnO nanorods are decorated with bimetallic AuPt nanoclusters that substantially augment the depletion of free carriers likely due to a more efficient absorption of the gas molecules on the surface of the bimetallic AuPt nanoclusters than on that of their monometallic counterparts. The depletion of free carriers in cluster decorated ZnO nanorods is quantitatively investigated and modelled, allowing the application of these composite materials in UV sensing and light induced catalysis.

Interplay Between V-ATPase G1 and Small EV-miRNAs Modulates ERK1/2 Activation in GBM Stem Cells and Nonneoplastic Milieu

The ATP6V1G1 subunit (V1G1) of the vacuolar proton ATPase (V-ATPase) pump is crucial for glioma stem cells (GSC) maintenance and in vivo tumorigenicity. Moreover, V-ATPase reprograms the tumor microenvironment through acidification and release of extracellular vesicles (EV). Therefore, we investigated the role of V1G1 in GSC small EVs and their effects on primary brain cultures. To this end, small EVs were isolated from patients-derived GSCs grown as neurospheres (NS) with high (V1G1^HIGH-NS) or low (V1G1^LOW-NS) V1G1 expression and analyzed for V-ATPase subunits presence, miRNA contents, and cellular responses in recipient cultures. Our results show that NS-derived small EVs stimulate proliferation and motility of recipient cells, with small EV derived from V1G1^HIGH-NS showing the most pronounced activity. This involved activation of ERK1/2 signaling, in a response reversed by V-ATPase inhibition in NS-producing small EV. The miRNA profile of V1G1^HIGH-NS-derived small EVs differed significantly from that of V1G1^LOW-NS, which included miRNAs predicted to target MAPK/ERK signaling. Mechanistically, forced expression of a MAPK-targeting pool of miRNAs in recipient cells suppressed MAPK/ERK pathway activation and blunted the prooncogenic effects of V1G1^HIGH small EV. These findings propose that the GSC influences the brain milieu through a V1G1-coordinated EVs release of MAPK/ERK-targeting miRNAs. Interfering with V-ATPase activity could prevent ERK-dependent oncogenic reprogramming of the microenvironment, potentially hampering local GBM infiltration. IMPLICATIONS: Our data identify a novel molecular mechanism of gliomagenesis specific of the GBM stem cell niche, which coordinates a V-ATPase-dependent reprogramming of the brain microenvironment through the release of specialized EVs.

Circulating fractures-related microRNAs distinguish primary hyperparathyroidism-related from estrogen withdrawal-related osteoporosis in postmenopausal osteoporotic women: A pilot study

Primary hyperparathyroidism (PHPT) represents a common cause of secondary osteoporosis in postmenopausal women, where the negative effect of estrogen withdrawal and that of hyperparathyroidism on bone mineralization coexist. Circulating microRNAs (miRNAs) expression profile has been correlated to both osteoporosis and fragility fractures. The study aimed to profile a set of miRNAs associated with osteoporotic fractures, namely miR-21-5p, miR-23a-5p, miR-24-2-5p, miR-24-3p, miR-93-5p, miR-100-5p, miR-122-5p, miR-124-3p, miR-125b-5p and miR-148-3p, in the plasma of 20 postmenopausal PHPT women. PHPT miRNAs profiles were compared with those detected in 10 age-matched postmenopausal non-PHPT osteoporotic women (OP). All the 10 miRNAs were detected in the plasma samples of both PHPT and OP women. The miRNA profiles clearly distinguished PHPT from OP samples, and identified within the PHPT group, two clusters differing for the PHPT severity, in term of ionized calcium and bone mineralization. In particular, miR-93-5p was significantly downregulated in PHPT samples, while miR-24-3p negatively correlated with the T-score at lumbar, femur neck and total hip sites. PHPT women who experienced osteoporotic fractures had plasma miR-24-3p levels higher than those detected in unfractured PHPT women. In conclusion, PHPT may modulate circulating fractures-related miRNAs, in particular, miR-93-5p, which may distinguish estrogen-related from PHPT-related osteoporosis.

A GBM-like V-ATPase signature directs cell-cell tumor signaling and reprogramming via large oncosomes

Background

The V-ATPase proton pump controls acidification of intra and extra-cellular milieu in both physiological and pathological conditions. We previously showed that some V-ATPase subunits are enriched in glioma stem cells and in patients with poor survival. In this study, we investigated how expression of a GBM-like V-ATPase pump influences the non-neoplastic brain microenvironment.

Methods

Large oncosome (LO) vesicles were isolated from primary glioblastoma (GBM) neurospheres, or from patient sera, and co-cultured with primary neoplastic or non-neoplastic brain cells. LO transcript and protein contents were analyzed by qPCR, immunoblotting and immunogold staining. Activation of pathways in recipient cells was determined at gene and protein expression levels. V-ATPase activity was impaired by Bafilomycin A1 or gene silencing.

Findings

GBM neurospheres influence their non-neoplastic microenvironment by delivering the V-ATPase subunit V1G1 and the homeobox genes HOXA7, HOXA10, and POU3F2 to recipient cells via LO. LOs reprogram recipient cells to proliferate, grow as spheres and to migrate. Moreover, LOs are particularly abundant in the circulation of GBM patients with short survival time. Finally, impairment of V-ATPase reduces LOs activity.

Interpretation

We identified a novel mechanism adopted by glioma stem cells to promote disease progression via LO-mediated reprogramming of their microenvironment. Our data provide preliminary evidence for future development of LO-based liquid biopsies and suggest a novel potential strategy to contrast glioma progression.

Fund

This work was supported by Fondazione Cariplo (2014-1148 to VV) and by the Italian Minister of Health-Ricerca Corrente program 2017 (to SF).

Abstract 3732: Insights into the non-coding genome of parathyroid tumors

Background. Parathyroid tumors are characterized by genetic and epigenetic alterations resulting in aberrant expression of protein coding genes and non-coding RNAs. Although long non-coding RNAs (lncRNAs) play a regulatory role in endocrine cancer pathogenesis, a lncRNAs signature in human parathyroid tumors is still missing. Here we investigated the lncRNAs alterations, both at genomic and transcriptional level, in human non-familial parathyroid tumors.

Methods. The expression of 90 lncRNAs was investigated in 4 parathyroid carcinomas (PCas), 12 adenomas (PAds) and 2 normal glands (PaNs) using a commercial array. Both unsupervised (hierarchical clustering-HCL and Principal Component Analysis-PCA) and supervised (Significance Analysis of Microarray, SAM) analyses were performed to identify differences in lncRNAs expression between the 3 tissue types. Significant lncRNAs were validated in a second set of parathyroid tissues including 7 PCas, 26 PAds, 6 atypical PAds (aPAds) and 4 PaNs. Genomic characterization of 21 PAds was performed by array Comparative Genomic Hybridization (aCGH). CDC73 and Multiple Endocrine Neoplasia 1 (MEN1) genes mutations were detected by Sanger sequencing.

Results. HCL analysis of lncRNAs expression identified 2 major groups in which PaNs and PCas were distinguished. Nine lncRNAs were differentially expressed in parathyroid tissues. Specifically, KCNQ1OT1 and SNHG6 were enriched in PaNs, HAR1B, MEG3, HOXA3as and NEAT1 expression characterized PAds, whereas BC200, HOXA6as and WT1-AS were significantly upregulated in PCas. Besides confirming previous data, validation analysis highlighted a different lncRNAs expression pattern in PCas and aPAds according to CDC73 mutation status, with mutated tumors overexpressing the majority of the lncRNAs. Interestingly, BACE1-AS, KCNQ1OT1, NEAT1 and SNHG6 levels in PAds were significantly correlated with MEN1 levels while HAR1B upregulation was associated with chromosome 11 loss of heterozygosity (LOH).

Conclusions. Overall these findings shed light on lncRNAs deregulation in parathyroid pathobiology. Parathyroid tumors histotypes are characterized by different lncRNAs signatures that are related to chromosome 11 derangements and to MEN1 inactivation. Finally, MEN1 may play an epigenetic role in lncRNAs regulation, supporting the important role of chromosome 11 in parathyroid tumorigenesis.

Citation Format: Annamaria Morotti, Irene Forno, Valentina Andrè, Vito Guarnieri, Andrea Terrasi, Rosa Maria Silipigni, Silvana Guerneri, Chiara Verdelli, Alfredo Scillitani, Leonardo Vicentini, Filomena Cetani, Edoardo Beretta, Sabrina Corbetta, Valentina Vaira. Insights into the non-coding genome of parathyroid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3732.

Expression of C19MC miRNAs in HCC associates with stem-cell features and the cancer-testis genes signature

BACKGROUND

Intratumor heterogeneity of hepatocellular carcinoma (HCC) and, among HCC cell subsets, the cancer stem cell population (hCSC), is responsible for therapeutic resistance and disease relapse.

AIMS

To characterize hCSC-enriched HCCs at the molecular level.

METHODS

Side population (SP) was used to identify the hCSCs in multiple tumor sampling from different patients and primary HCCs cultures. FACS was used to immunoprofile cultures. miRNAs were profiled in samples and correlated to SP. The Cancer Genome Atlas (TCGA) HCC dataset was analyzed to search for signatures associated with C19MC miRNAs expression. Results were confirmed by immunohistochemistry.

RESULTS

The miRNA cluster on chromosome 19 (C19MC) was enriched in SP and in HCCs with a high SP fraction. At the molecular level, an elevated C19MC was correlated with expression of precursor transcripts. In TCGA-HCC series, high C19MC expression identified a subset of patients with poorer prognosis, advanced disease and overexpression of the cancer-testis (CT) antigens. These data were confirmed in an independent cohort of HCCs and at the protein level.

CONCLUSION

C19MC miRNAs and CT antigens overexpression represents a novel oncogenic pathway in a subset of hCSC-enriched HCCs with dismal prognosis. CT antigens are promising immunotherapy targets. Therefore, these molecular signatures could identify HCCs who could benefit from immunotherapy.

Abstract 2889: V-ATPase control of EV signaling in glioma stem cells

Background: Recent evidences highlighted that GBM secreted microvesicles (EVs), particularly exosomes (Exo) and large oncosomes (LO), play a major role in the cross-talk between tumor cell and non-neoplastic parenchyma. How GBMs manage to thrive in a highly unfavorable, acidic microenvironment is still unclear, but recent work from our group has identified the vacuolar pump H+-ATPase (V-ATPase) as an important effector of GBM growth and glioma stem cells (GSC) maintenance. Additionally, in ExoCarta database V-ATPase subunits have been described in Exo from different cancer cell types.

Taken together, these data identify V-ATPase as an important driver of gliomagenesis, and a novel, actionable therapeutic target for disease intervention. However, the role of V-ATPase in reprogramming the GBM microenvironment has not been previously investigated.

Methods: Exo and LO were isolated by an Invitrogen kit and serial centrifugation, respectively, from media of patients’ derived GBM neurospheres, enriched in GSC (NS, n=12) or differentiated cultures (n=8). For EVs internalization studies, Exo or LO were stained using FM 1-43 FX dye and the process was followed live for 30’ and at selected time points (30’-4h-24h), using a confocal microscopy or flow cytometry (FACS). Electron microscopy, FACS (of Exo stained with CellTrace and SytoRNA in combination with CD63 coated beads), Nanosight and immunoblotting (for CD63, CD9 and Clathrin) analyses were used to confirm EVs subtypes. Cultures from patients’ derived brain tumor margins or primary GBM (differentiated and not) were used as EVs-recipient cells. miRNA profiling was performed using Taqman Low density arrays and analyzed by R packages. Gene Ontology analysis was performed by DAVID. The study was approved by the Institutional Ethical Committee.

Results: NS are able to produce different EVs, which are internalized by recipient cells after 4 and up to 24 hours of co-culture. Both Exo than LO from NS are able to significantly increase cell growth in recipient cells (brain tumor margins and primary GMB differentiated monolayers), and this effect is stronger with EVs produced by NS with higher V-ATPase expression (V-ATPaseHIGH NS). Primary GBM cells after co-culture with EVs are able to produce a higher number of NS and V-ATPase activity block by BafilomycinA1 in NS-producing EVs completely revert this effect. Finally, the co-culture of V-ATPaseLOW NS with EVs from V-ATPaseHIGH NS increases their motility in collagen matrixes.

At molecular level, profiling of Exo-derived miRNAs distinguishes differentiated cultures from NS and, among NS, V-ATPaseHIGH cultures. In silico analysis and annotation of miRNA target genes from V-ATPaseHIGH–derived Exo showed an enrichment of cancer, cell cycle and PI3K/Akt pathways.

Conclusions: Altogether, these data point toward the central role of different EV types in GBM communication and suggest a role of the V-ATPase proton pump in regulating EV’s contents.

Citation Format: Irene Bertolini, Andrea Terrasi, Andrea Di Cristofori, Silvano Bosari, Valentina Vaira. V-ATPase control of EV signaling in glioma stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2889. doi:10.1158/1538-7445.AM2017-2889

Recurrent NAB2-STAT6 gene fusions and oestrogen receptor-α expression in pulmonary adenofibromas

AIMS

Pulmonary adenofibromas are rare benign fibroepithelial tumours of the lung with unknown histogenesis and an indolent clinical behaviour. Their stroma resembles that of solitary fibrous tumours, whereas the glands are composed of respiratory epithelium organized in a phyllodes-like architecture. Differentiation of pulmonary adenofibromas from other more aggressive intrathoracic tumours is clinically relevant. However, their biology is unknown. Here, we sought to characterize pulmonary adenofibromas at a clinicopathological level and to define whether they could be underpinned by a highly recurrent somatic genetic alteration akin to tumours with similar morphology.

METHODS AND RESULTS

Seven pulmonary adenofibromas were subjected to immunohistochemical analysis for thyroid transcription factor 1 (TTF1), napsin A, cytokeratin 7, E-cadherin, CD99, CD34, CD31, STAT6, oestrogen receptor (ER), progesterone receptor, androgen receptor, bcl-2, and vimentin, as well as electron microscopy and capillary sequencing on microdissected samples to evaluate the presence of NAB2-STAT6 fusion genes and MED12 exon 2 mutations in their discrete components. A control group comprising pulmonary solitary fibrous tumours, pulmonary hamartomas and breast fibroadenomas was also analysed. We confirmed that the stromal elements of pulmonary adenofibromas pertain to the fibroblastic lineage, and show ER overexpression in 71% of cases, whereas the epithelium consists of TTF1-positive, E-cadherin positive bronchiolar elements. A highly recurrent NAB2-STAT6 fusion variant (exon 4-exon 2) was detected in the stroma but not in the epithelium. No MED12 mutations were identified.

CONCLUSIONS

Here, we demonstrate that pulmonary adenofibromas are neoplastic lesions harbouring the molecular hallmark of solitary fibrous tumours.

CD18 promoter methylation is associated with a higher risk of thrombotic complications in primary myelofibrosis

Morbidity and mortality of BCR-ABL1-negative myeloproliferative neoplasm (MPN) patients are influenced by disease-related hemostatic complications, mostly of thrombotic nature. The pathogenesis of thrombosis is multifactorial: in particular, it has been demonstrated that a deregulated expression of Mac1 (also known as surface receptor integrin CD18/CD11b) by leukocytes has a role in favoring platelets' activation in MPN patients. Based on these data, we investigated the epigenetic status of CD18/CD11b in 78 primary myelofibrosis (PMF) patients to explore any possible association between the epigenetic profiles of these two genes and thrombotic risk. The percentage of CD18 methylation in the PMF samples ranged from hypomethylated to hypermethylated (range: 11-90 %, mean: 64 %), whereas in controls CD18 methylation status clustered in a more restricted interval (range: 24-68 %, mean: 45 %; cases vs.

CONTROLS

p = 0.006). Furthermore, the results showed that CD18 hypermethylation (>76 % methylation) was correlated with thrombotic complications. On the contrary, CD11b promoter resulted unmethylated (1-5 %) in both cases and controls. Previous studies showed that older age, JAK2V617F mutation, and thrombophilia might play a role in MPN patients' thrombotic risk. In our cases, the prognostic value of these variables was coherent, being thrombotic events significantly associated with age >65 years (p = 0.001), JAK2 mutation (p = 0.01), and positive thrombophilia tests (p = 0.04). However, multivariate analysis showed that only CD18 methylation and age >65 years were independent prognostic factors of thrombosis (p = 0.02 and p = 0.04, respectively). Taken together, our findings suggest a possible role of CD18 epigenetic regulation in the pathogenesis of the thrombotic complications in PMF patients.

Radiative mechanism and surface modification of four visible deep level defect states in ZnO nanorods

Visible luminescence from ZnO nanorods (NRs) is attracting large scientific interest for light emission and sensing applications. We study visible luminescent defects in ZnO NRs as a function of post growth thermal treatments, and find four distinct visible deep level defect states (VDLSs): blue (2.52 eV), green (2.23 eV), orange (2.03 eV), and red (1.92 eV). Photoluminescence (PL) studies reveal a distinct modification in the UV (3.25 eV) emission intensity and a shift in the visible spectra after annealing. Annealing at 600 °C in Ar (Ar600) and O2 (O600) causes a blue and red-shift in the visible emission band, respectively. All samples demonstrate orange emission from the core of the NR, with an additional surface related green, blue, and red emission in the As-Prep, Ar600, and O600 samples, respectively. From PL excitation (PLE) measurements we determine the onset energy for population of the various VDLSs, and relate it to the presence of an Urbach tail below the conduction band due to a presence of ionized Zni or Zni complexes. We measured an onset energy of 3.25 eV for the as prepared sample. The onset energy red-shifts in the annealed samples by about 0.05 to 0.1 eV indicating a change in the defect structure, which we relate to the shift in the visible emission. We then used X-ray photoemission spectroscopy (XPS), and elastic recoil detection analysis (ERDA) to understand changes in the surface structure, and H content, respectively. The results of the XPS and ERDA analysis explain how the chemical states are modified due to annealing. We summarize our results by correlating our VDLSs with specific intrinsic defect states to build a model for PL emission in ZnO NRs. These results are important for understanding how to control defect related visible emission for sensing and electroluminescence applications.

Abstract 4760: Stromal contribution to the colorectal cancer transcriptome

Recent studies have identified a stem/serrated/mesenchymal (SSM) molecular subtype of colorectal cancer (CRC) that is associated with poor prognosis. We noted that genes upregulated in this subtype are also prominently expressed by stromal cells. This led us to hypothesize that the SSM transcripts could derive from the tumor microenvironment, rather than being intrinsic to cancer cells. To test this hypothesis, we analyzed microarray and RNAseq expression data from patient-derived xenografts (PDXs) of CRC, where human cancer cells are supported by murine stroma. Species-specific expression analysis revealed that mRNA levels of SSM genes are mostly due to stromal expression. Considering only genes exclusively expressed by stromal cells in PDXs, We then built three expression signatures specifically reporting the abundance of cancer-associated fibroblasts (CAFs), leucocytes or endothelial cells. In human CRC samples, all stromal signatures were strongly associated with the SSM subtype. A high CAF signature was associated with poor prognosis in untreated CRC patients, while in rectal cancer high stromal signatures jointly predicted radioresistance. These data show that the distinctive transcriptional and clinical features of the SSM subtype can be ascribed to its particularly abundant stroma.

Citation Format: Claudio Isella, Andrea Terrasi, Sara E. Bellomo, Consalvo Petti, Andrea Muratore, Alfredo Mellano, Mark De Ridder, Paola Cassoni, Guy Storme, Andrea Bertotti, Enzo Medico. Stromal contribution to the colorectal cancer transcriptome. [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 4760. doi:10.1158/1538-7445.AM2015-4760

The role of the interface in germanium quantum dots: when not only size matters for quantum confinement effects

Quantum confinement (QC) typically assumes a sharp interface between a nanostructure and its environment, leading to an abrupt change in the potential for confined electrons and holes. When the interface is not ideally sharp and clean, significant deviations from the QC rule appear and other parameters beyond the nanostructure size play a considerable role. In this work we elucidate the role of the interface on QC in Ge quantum dots (QDs) synthesized by rf-magnetron sputtering or plasma enhanced chemical vapor deposition (PECVD). Through a detailed electron energy loss spectroscopy (EELS) analysis we investigated the structural and chemical properties of QD interfaces. PECVD QDs exhibit a sharper interface compared to sputter ones, which also evidences a larger contribution of mixed Ge-oxide states. Such a difference strongly modifies the QC strength, as experimentally verified by light absorption spectroscopy. A large size-tuning of the optical bandgap and an increase in the oscillator strength occur when the interface is sharp. A spatially dependent effective mass (SPDEM) model is employed to account for the interface difference between Ge QDs, pointing out a larger reduction in the exciton effective mass in the sharper interface case. These results add new insights into the role of interfaces on confined systems, and open the route for reliable exploitation of QC effects.

Stromal contribution to the colorectal cancer transcriptome

Recent studies identified a poor-prognosis stem/serrated/mesenchymal (SSM) transcriptional subtype of colorectal cancer (CRC). We noted that genes upregulated in this subtype are also prominently expressed by stromal cells, suggesting that SSM transcripts could derive from stromal rather than epithelial cancer cells. To test this hypothesis, we analyzed CRC expression data from patient-derived xenografts, where mouse stroma supports human cancer cells. Species-specific expression analysis showed that the mRNA levels of SSM genes were mostly due to stromal expression. Transcriptional signatures built to specifically report the abundance of cancer-associated fibroblasts (CAFs), leukocytes or endothelial cells all had significantly higher expression in human CRC samples of the SSM subtype. High expression of the CAF signature was associated with poor prognosis in untreated CRC, and joint high expression of the stromal signatures predicted resistance to radiotherapy in rectal cancer. These data show that the distinctive transcriptional and clinical features of the SSM subtype can be ascribed to its particularly abundant stromal component.