Search

Abstract Non-small-cell lung carcinoma (NSCLC) is the most common lung cancer and one of the pioneer tumors in which immunotherapy has radically changed patients’ outcomes. However, several issues are emerging and their implementation is required to optimize immunotherapy-based protocols. In this work, we investigate the ability of the Bromodomain and Extra-Terminal protein inhibitors (BETi) to stimulate a proficient anti-tumor immune response toward NSCLC. By using in vitro, ex-vivo, and in vivo models, we demonstrate that these epigenetic drugs specifically enhance Natural Killer (NK) cell cytotoxicity. BETi down-regulate a large set of NK inhibitory receptors, including several immune checkpoints (ICs), that are direct targets of the transcriptional cooperation between the BET protein BRD4 and the transcription factor SMAD3. Overall, BETi orchestrate an epigenetic reprogramming that leads to increased recognition of tumor cells and the killing ability of NK cells. Our results unveil the opportunity to exploit and repurpose these drugs in combination with immunotherapy.

Binder Jetting (BJT) is a non-fusion-based Additive Manufacturing (AM) technique. It consists of the selective deposition of a liquid binder to join powder particles, thereby enabling the creation of near-net-shaped parts.In this study, the main printing parameters correlated to the binder distribution and infiltration (binder saturation, binder set time, drying time, and target bed temperature) were optimised to improve the precision of green parts printed with potassium sodium niobate (KNN) powder. The optimisation procedure was conducted using the Taguchi statistical method. An L9 orthogonal array with four factors of control at three levels each was employed. The analysis showed that the drying time had the greatest influence on the precision of green parts, followed by binder saturation and target bed temperature. Binder set time did not seem to affect the results.Dimensional analysis, microstructural and piezoelectric characterisation of parts densified by pressureless sintering were conducted. The highest average relative density exceeded 80% for the specimens printed with the lower binder saturation. Piezoelectric properties exhibit more complex behaviour. The prolonged infiltration of larger binder volumes is correlated to higher g33, thus FOMh and FOM33, and lower values for ε33T. On the other hand, d33 does not display a specific dependence on density or printing parameters.The results of this study indicate that BJT can be used to fabricate high-precision KNN components with good piezoelectric properties. The optimisation of printing parameters is essential to achieve the desired results.

ABSTRACT Background Myeloid neoplasms, including acute myeloid leukemia, have been traditionally among the less investigated cancer types concerning germline predisposition. Indeed, myeloid neoplasms with germline predisposition are challenging to identify because often display similar clinical and morphological characteristics of sporadic cases and have similar age at diagnosis. However, a misidentifications of familiarity in myeloid neoplasms have a critical impact on clinical management both for the carriers and their relatives. Aims We conducted a family segregation study, in order to identify novel cancer predisposing genes in myeloid neoplasms and classify novel identified variants. Methods and Results We performed a thorough genomic analysis using a large custom gene panel (256 genes), the Myelo‐Panel, targeted on cancer predisposing genes. In particular, we assessed both germline and somatic variants in four families, each with two siblings, who developed hematological neoplasms: seven acute myeloid leukemia and one Philadelphia‐positive chronic myeloid leukemia. In each family, we identified at least one novel potentially predisposing variant, affecting also genes not included in the current European LeukemiaNet guidelines for AML management. Moreover, we suggest reclassification of two germline variants as pathogenic: likely pathogenic p.S21Tfs*139 in CEPBA and VUS p.K392Afs*66 in DDX41. Conclusion We believe that predisposition to hematological neoplasms is still underestimated and particularly difficult to diagnosed. Considering that misidentification of familiarity in myeloid neoplasms have a critical impact on the clinical management both for the carriers and their relatives, our study highlights the importance of revision, in this clinical context, of clinical practices that should include thorough reconstruction of family history and in‐depth genetic testing.

Background: The management of locally advanced rectal cancer (LARC) relies on a multimodal approach. Neither instrumental work-up nor molecular biomarkers are currently available to identify a risk-adapted strategy. Objectives: We aim to investigate the role of circulating tumor DNA (ctDNA) and its clearance at different timepoints during chemo-radiotherapy (CRT) and correlate them with clinical outcomes. Design: Between November 2014 and November 2019, we conducted a monocentric prospective observational study enrolling consecutive patients with LARC managed with neoadjuvant standard CRT (capecitabine and concomitant pelvic long-course radiotherapy), followed by consolidation capecitabine in selected cases and surgery. Methods: Blood samples for ctDNA were obtained at pre-planned timepoints. We evaluated the correlation of baseline variant allele frequency (VAF) with pathologic complete response (pCR) down-staging, node regression (pN0), event-free survival (EFS), and overall survival (OS). Results: Among 112 screened patients, 61 were enrolled. In all, 38 (62%) had a positive ctDNA at baseline with VAF > 0 and 23 had negative ctDNA (VAF = 0). Among patients with negative ctDNA, 30% had a complete response, while only 13% of positive ctDNA patients had pCR [odds ratio (OR) 0.35 (95% confidence interval (CI): 0.10–1.26), p = 0.11]. Similarly, 96% and 74% of pN0 were observed among negative and positive ctDNA patients, respectively [OR 0.13 (95% CI: 0.02–1.07), p = 0.058]. The presence of a baseline VAF > 0 was associated with a trend toward a lower EFS compared with VAF = 0 patients [hazard ratio (HR) = 2.30, 95% CI: 0.63–8.36, p = 0.21]. Within the limitations of small sample size, no difference in OS was observed according to the baseline ctDNA status (HR = 1.18, 95% CI: 0.35–4.06, p = 0.79). Conclusion: Within the limitations of a reduced number of patients, patients with baseline negative ctDNA seem to show a higher probability of pN0 status and a trend toward improved EFS. Prospective translational studies are required to define the role of ctDNA analysis in the multimodal treatment of LARC.

Abstract Background Gorongosa National Park in Mozambique hosts a large population of baboons, numbering over 200 troops. Gorongosa baboons have been tentatively identified as part of Papio ursinus on the basis of previous limited morphological analysis and a handful of mitochondrial DNA sequences. However, a recent morphological and morphometric analysis of Gorongosa baboons pinpointed the occurrence of several traits intermediate between P. ursinus and P. cynocephalus, leaving open the possibility of past and/or ongoing gene flow in the baboon population of Gorongosa National Park. In order to investigate the evolutionary history of baboons in Gorongosa, we generated high and low coverage whole genome sequence data of Gorongosa baboons and compared it to available Papio genomes. Results We confirmed that P. ursinus is the species closest to Gorongosa baboons. However, the Gorongosa baboon genomes share more derived alleles with P. cynocephalus than P. ursinus does, but no recent gene flow between P. ursinus and P. cynocephalus was detected when available Papio genomes were analyzed. Our results, based on the analysis of autosomal, mitochondrial and Y chromosome data, suggest complex, possibly male-biased, gene flow between Gorongosa baboons and P. cynocephalus, hinting to direct or indirect contributions from baboons belonging to the “northern” Papio clade, and signal the presence of population structure within P. ursinus. Conclusions The analysis of genome data generated from baboon samples collected in central Mozambique highlighted a complex set of evolutionary relationships with other baboons. Our results provided new insights in the population dynamics that have shaped baboon diversity.

Abstract Breast cancer (BC) constitutes a major health problem worldwide, making it the most common malignancy in women. Current treatment options for BC depend primarily on histological type, molecular markers, clinical aggressiveness and stage of disease. Immunotherapy, such as αPD-1, have shown combinatorial clinical activity with chemotherapy in triple negative breast cancer (TNBC) delineating some therapeutic combinations as more effective than others. However, a clear overview of the main immune cell populations involved in these treatments has never been provided. Here, an assessment of the immune landscape in the tumor microenvironment (TME) of two TNBC mouse models has been performed using single-cell RNA sequencing technology. Specifically, immune cells were evaluated in untreated conditions and after treatments with chemotherapy or immunotherapy used as single agents or in combination. A decrease of Treg was found in treatments with in vivo efficacy as well as γδ T cells, which have a pro-tumoral activity in mice. Focusing on Cd8 T cells, across all the conditions, a general increase of exhausted-like Cd8 T cells was confirmed in pre-clinical treatments with low efficacy and an opposite trend was found for the proliferative Cd8 T cells. Regarding macrophages, M2-like cells were enriched in treatments with low efficacy while M1-like macrophages followed an opposite trend. For both models, similar proportions of B cells were detected with an increase of proliferative B cells in treatments involving cisplatin in combination with αPD-1. The fine-scale characterization of the immune TME in this work can lead to new insights on the diagnosis and treatment of TNBC.

Abstract Leukemic cells proliferate faster than non-transformed counterparts. This requires them to change their metabolism to adapt to their high growth. This change can stress cells and facilitate recognition by immune cells such as cytotoxic lymphocytes, which express the activating receptor Natural Killer G2-D (NKG2D). The tumor suppressor gene p53 regulates cell metabolism, but its role in the expression of metabolism-induced ligands, and subsequent recognition by cytotoxic lymphocytes, is unknown. We show here that dichloroacetate (DCA), which induces oxidative phosphorylation (OXPHOS) in tumor cells, induces the expression of such ligands, e.g. MICA/B, ULBP1 and ICAM-I, by a wtp53-dependent mechanism. Mutant or null p53 have the opposite effect. Conversely, DCA sensitizes only wtp53-expressing cells to cytotoxic lymphocytes, i.e. cytotoxic T lymphocytes and NK cells. In xenograft in vivo models, DCA slows down the growth of tumors with low proliferation. Treatment with DCA, monoclonal antibodies and NK cells also decreased tumors with high proliferation. Treatment of patients with DCA, or a biosimilar drug, could be a clinical option to increase the effectiveness of CAR T cell or allogeneic NK cell therapies.

Abstract Solid tumor cells have an altered metabolism that can protect them from cytotoxic lymphocytes. The anti-diabetic drug metformin modifies tumor cell metabolism and several clinical trials are testing its effectiveness for the treatment of solid cancers. The use of metformin in hematologic cancers has received much less attention, although allogeneic cytotoxic lymphocytes are very effective against these tumors. We show here that metformin induces expression of Natural Killer G2-D (NKG2D) ligands (NKG2DL) and intercellular adhesion molecule-1 (ICAM-1), a ligand of the lymphocyte function-associated antigen 1 (LFA-1). This leads to enhance sensitivity to cytotoxic lymphocytes. Overexpression of anti-apoptotic Bcl-2 family members decrease both metformin effects. The sensitization to activated cytotoxic lymphocytes is mainly mediated by the increase on ICAM-1 levels, which favors cytotoxic lymphocytes binding to tumor cells. Finally, metformin decreases the growth of human hematological tumor cells in xenograft models, mainly in presence of monoclonal antibodies that recognize tumor antigens. Our results suggest that metformin could improve cytotoxic lymphocyte-mediated therapy.

The contribution of cell-extrinsic factors in Acute Myeloid Leukemia (AML) generation and persistence has gained interest. Bitter taste receptors (TAS2Rs) are G protein-coupled receptors known for their primary role as a central warning signal to induce aversion toward noxious or harmful substances. Nevertheless, the increasing amount of evidence about their extra-oral localization has suggested a wider function in sensing microenvironment, also in cancer settings. In this study, we found that AML cells express functional TAS2Rs. We also highlighted a significant association between the modulation of some TAS2Rs and the poor-prognosis AML groups, i.e., TP53- and TET2-mutated, supporting a potential role of TAS2Rs in AML cell biology. Gene expression profile analysis showed that TAS2R activation with the prototypical agonist, denatonium benzoate, significantly modulated a number of genes involved in relevant AML cellular processes. Functional assay substantiated molecular data and indicated that denatonium reduced AML cell proliferation by inducing cell cycle arrest in G0/G1 phase or induced apoptosis via caspase cascade activation. Moreover, denatonium exposure impaired AML cell motility and migratory capacity, and inhibited cellular respiration by decreasing glucose uptake and oxidative phosphorylation. In conclusion, our results in AML cells expand the observation of cancer TAS2R expression to the setting of hematological neoplasms and shed light on a role of TAS2Rs in the extrinsic regulation of leukemia cell functions.

Background Rituximab in combination with chemotherapy is now widely accepted as standard of care for AIDS-related lymphomas (ARLs) of B-cell origin. However, the clinical impact of rituximab in resource limited settings remains unknown. Different settings and patient heterogeneity may affect the effect of any given treatment. The study objectives were to determine if rituximab use was associated with improved 18-month overall survival (OS) of patients with ARLs and to identify correlates of 18-month OS. Methods A retrospective review of medical records of adult HIV infected patients treated for high-grade large cell non-Hodgkin’s lymphoma with chemotherapy +/- rituximab between 2015–2017 was conducted. Vital status and disease progression/relapse at 18 months were determined. Survival functions were estimated using Kaplan-Meier methodology. Equality of survival functions were assessed using Log-rank tests and Cox regression analysis to identify risk factors for mortality. Results One hundred and twenty-four eligible medical records were identified. This was a cohort of black Africans with a median age of 42 (IQR: 33–47) and a 57% male gender distribution. Overall survival at 6, 12 and 18 months for the population was 75.9%, 44.0% and 30.6% respectively. Over the study period, 72.6% of patients were diagnosed with disease progression/ relapse. There was a higher rate of rituximab use in patients who were treated at a private institution and those with medical insurance. Rituximab use was not associated with a reduction in 18-month mortality [adjusted hazard ratio (aHR)1.28, (95% CI 0.63–2.60)]. Risk factors for 18-month mortality were male gender [aHR 1.89, (95% CI 1.04–3.43)], age 40+ years [aHR 2.49, (1.33–4.67)], receipt of

Hypomethylating agents are a classical frontline low-intensity therapy for older patients with acute myeloid leukemia. Recently, TP53 gene mutations have been described as a potential predictive biomarker of better outcome in patients treated with a ten-day decitabine regimen., However, functional characteristics of TP53 mutant are heterogeneous, as reflected in multiple functional TP53 classifications and their impact in patients treated with azacitidine is less clear. We analyzed the therapeutic course and outcome of 279 patients treated with azacitidine between 2007 and 2016, prospectively enrolled in our regional healthcare network. By screening 224 of them, we detected TP53 mutations in 55 patients (24.6%), including 53 patients (96.4%) harboring high-risk cytogenetics. The identification of any TP53 mutation was associated with worse overall survival but not with response to azacitidine in the whole cohort and in the subgroup of patients with adverse karyotype. Stratification of patients according to three recent validated functional classifications did not allow the identification of TP53 mutated patients who could benefit from azacitidine. Systematic TP53 mutant classification will deserve further exploration in the setting of patients treated with conventional therapy and in the emerging field of therapies targeting TP53 pathway.

Abstract Oxidative phosphorylation (OXPHOS) generates ROS as a byproduct of mitochondrial complex I activity. ROS-detoxifying enzymes are made available through the activation of their antioxidant response elements (ARE) in their gene promoters. NRF2 binds to AREs and induces this anti-oxidant response. We show that cells from multiple origins performing OXPHOS induced NRF2 expression and its transcriptional activity. The NRF2 promoter contains MEF2 binding sites and the MAPK ERK5 induced MEF2-dependent NRF2 expression. Blocking OXPHOS in a mouse model decreased Erk5 and Nrf2 expression. Furthermore, fibroblasts derived from patients with mitochondrial disorders also showed low expression of ERK5 and NRF2 mRNAs. Notably, in cells lacking functional mitochondrial complex I activity OXPHOS did not induce ERK5 expression and failed to generate this anti-oxidant response. Complex I activity induces ERK5 expression through fumarate accumulation. Eukaryotic cells have evolved a genetic program to prevent oxidative stress directly linked to OXPHOS and not requiring ROS.

Disease relapse caused by drug resistance still represents a major clinical hurdle in cancer treatments. Tumor cells may take advantage of different intracellular and genetic systems attenuating the drug effects. Resistant cells or minimal residual disease (MRD) cells have strong clinical relevance, as they might give rise to secondary tumors when the therapy is concluded. Thus, MRDs are crucial therapeutic targets in order to prevent tumor relapse. Therefore, several groups aim at understanding how MRDs are orginated, characterizing their molecular features, and eradicating them. In this review, we will describe MRD from a genetic, evolutionary, and molecular point of view. Moreover, we will focus on the new in vitro, in vivo, preclinical, and clinical studies that aim at eradicating tumor resistance.

Abstract Controlling cholesterol levels is a major challenge in human health, since hypercholesterolemia can lead to serious cardiovascular disease. Drugs that target carbohydrate metabolism can also modify lipid metabolism and hence cholesterol plasma levels. In this sense, dichloroacetate (DCA), a pyruvate dehydrogenase kinase (PDK) inhibitor, augments usage of the glycolysis-produced pyruvate in the mitochondria increasing oxidative phosphorylation (OXPHOS). In several animal models, DCA decreases plasma cholesterol and triglycerides. Thus, DCA was used in the 70 s to treat diabetes mellitus, hyperlipoproteinemia and hypercholesterolemia with satisfactory results. However, the mechanism of action remained unknown and we describe it here. DCA increases LDLR mRNA and protein levels as well as LDL intake in several cell lines, primary human hepatocytes and two different mouse models. This effect is mediated by transcriptional activation as evidenced by H3 acetylation on lysine 27 on the LDLR promoter. DCA induces expression of the MAPK ERK5 that turns on the transcription factor MEF2. Inhibition of this ERK5/MEF2 pathway by genetic or pharmacological means decreases LDLR expression and LDL intake. In summary, our results indicate that DCA, by inducing OXPHOS, promotes ERK5/MEF2 activation leading to LDLR expression. The ERK5/MEF2 pathway offers an interesting pharmacological target for drug development.

Surgery remains the most successful curative treatment for cancer. However, some patients with early-stage disease who undergo surgery eventually succumb to distant metastasis. Here, we show that in response to surgery, the lungs become more vulnerable to metastasis due to extracellular matrix remodeling. Mice that undergo surgery or that are preconditioned with plasma from donor mice that underwent surgery succumb to lung metastases earlier than controls. Increased lysyl oxidase (LOX) activity and expression, fibrillary collagen crosslinking, and focal adhesion signaling contribute to this effect, with the hypoxic surgical site serving as the source of LOX. Furthermore, the lungs of recipient mice injected with plasma from post-surgical colorectal cancer patients are more prone to metastatic seeding than mice injected with baseline plasma. Downregulation of LOX activity or levels reduces lung metastasis after surgery and increases survival, highlighting the potential of LOX inhibition in reducing the risk of metastasis following surgery.

Tyrosine kinases have been implicated in promoting tumorigenesis of several human cancers. Exploiting these vulnerabilities has been shown to be an effective anti-tumor strategy as demonstrated for example by the Bruton's tyrosine kinase (BTK) inhibitor, ibrutinib, for treatment of various blood cancers. Here, we characterize a new multiple kinase inhibitor, ARQ531, and evaluate its mechanism of action in preclinical models of acute myeloid leukemia. Treatment with ARQ531, by producing global signaling pathway deregulation, resulted in impaired cell cycle progression and survival in a large panel of leukemia cell lines and patient-derived tumor cells, regardless of the specific genetic background and/or the presence of bone marrow stromal cells. RNA-seq analysis revealed that ARQ531 constrained tumor cell proliferation and survival through Bruton's tyrosine kinase and transcriptional program dysregulation, with proteasome-mediated MYB degradation and depletion of short-lived proteins that are crucial for tumor growth and survival, including ERK, MYC and MCL1. Finally, ARQ531 treatment was effective in a patient-derived leukemia mouse model with significant impairment of tumor progression and survival, at tolerated doses. These data justify the clinical development of ARQ531 as a promising targeted agent for the treatment of patients with acute myeloid leukemia.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematologic malignancy for which there is still no effective therapy. In order to identify genetic alterations useful for a new treatment design, we used whole-exome sequencing to analyze 14 BPDCN patients and the patient-derived CAL-1 cell line. The functional enrichment analysis of mutational data reported the epigenetic regulatory program to be the most significantly undermined (P

Tumor cell metabolism is altered during leukemogenesis. Cells performing oxidative phosphorylation (OXPHOS) generate reactive oxygen species (ROS) through mitochondrial activity. To limit the deleterious effects of excess ROS, certain gene promoters contain antioxidant response elements (ARE), e.g. the genes NQO-1 and HO-1. ROS induces conformational changes in KEAP1 and releases NRF2, which activates AREs. We show in vitro and in vivo that OXPHOS induces, both in primary leukemic cells and cell lines, de novo expression of NQO-1 and HO-1 and also the MAPK ERK5 and decreases KEAP1 mRNA. ERK5 activates the transcription factor MEF2, which binds to the promoter of the miR-23a–27a–24-2 cluster. Newly generated miR-23a destabilizes KEAP1 mRNA by binding to its 3′UTR. Lower KEAP1 levels increase the basal expression of the NRF2-dependent genes NQO-1 and HO-1. Hence, leukemic cells performing OXPHOS, independently of de novo ROS production, generate an antioxidant response to protect themselves from ROS.

Genomic instability plays a pathological role in various malignancies, including acute myeloid leukemia (AML), and thus represents a potential therapeutic target. Recent studies demonstrate that SIRT6, a NAD+-dependent nuclear deacetylase, functions as genome-guardian by preserving DNA integrity in different tumor cells. Here, we demonstrate that also CD34+ blasts from AML patients show ongoing DNA damage and SIRT6 overexpression. Indeed, we identified a poor-prognostic subset of patients, with widespread instability, which relies on SIRT6 to compensate for DNA-replication stress. As a result, SIRT6 depletion compromises the ability of leukemia cells to repair DNA double-strand breaks that, in turn, increases their sensitivity to daunorubicin and Ara-C, both in vitro and in vivo. In contrast, low SIRT6 levels observed in normal CD34+ hematopoietic progenitors explain their weaker sensitivity to genotoxic stress. Intriguingly, we have identified DNA-PKcs and CtIP deacetylation as crucial for SIRT6-mediated DNA repair. Together, our data suggest that inactivation of SIRT6 in leukemia cells leads to disruption of DNA-repair mechanisms, genomic instability and aggressive AML. This synthetic lethal approach, enhancing DNA damage while concomitantly blocking repair responses, provides the rationale for the clinical evaluation of SIRT6 modulators in the treatment of leukemia.

Cell fusion plays a well-recognized physiological role during development, while its function during progression is still unclear. Here, we show that acute myeloid leukemia (AML) cells spontaneously fused with murine host cells in vivo. AML cells fused in most cases with mouse macrophages. Other targets of AML cell fusion were dendritic and endothelial cells. Cytogenetic and molecular analysis revealed that successive recipients conserved detectable amounts of parental DNA. Moreover, in a mouse AML1-ETO model where female AML1-ETO-leukemic cells, expressing CD45.2, were injected in congenic CD45.1 male mice AML cells, we found hybrid cells expressing both allelic types of CD45 and XXY set of sexual chromosomes. More importantly, the fusion protein AML1-ETO was transferred in the hybrid cells. When sorted hybrid cells were reinjected in a secondary recipient, they gave rise to leukemia with 100% penetrance and similar time of onset of leukemic cells. Our data indicate that in vivo fusion of cancer cells with host cells may be a mechanism of gene transfer for cancer dissemination and suggest that fused cells may be used to identify still unrecognized leukemogenic genes that are conserved in hybrid cells and able to perpetuate leukemia in vivo.

Fluorescence in situ hybridization (FISH) represents a major step in the analysis of chromosomal aberrations in cancer. It allows the precise detection of specific rearrangements, both for diagnostic and prognostic purposes. Here we present a miniaturized FISH method performed on fresh and fixed hematological samples. This procedure has been developed together with a microfluidic device that integrates cluster-assembled nanostructured TiO2 (ns-TiO2) as a nanomaterial promoting hematopoietic cell immobilization in conditions of shear stress. As a result of miniaturization, FISH can be performed with at least a 10-fold reduction in probe usage and minimal cell requirements, creating the possibility of using FISH in genetic screening applications. We developed the protocol on tumor cells and bone marrow (BM) from a normal donor using commercially sex-specific and onco-hematology probes. The procedure was then validated using either BM or peripheral blood (PB) from six patients with hematological diseases, each associated with different genetic lesions. Miniaturized FISH demonstrated comparable performance to standard FISH, indicating that it is suitable for genetic screenings, in research, and in clinical settings for the diagnosis of samples from onco-hematological malignancies.

BACKGROUND:The endothelium is not a homogeneous organ. Endothelial cell heterogeneity has been described at the level of cell morphology, function, gene expression, and antigen composition. As a consequence of the genetic, transcriptome and surrounding environment diversity, endothelial cells from different vascular beds have differentiated functions and phenotype. Detection of circulating endothelial cells (CECs) by flow cytometry is an approach widely used in cancer patients, and their number, viability and kinetic is a promising tool to stratify patient receiving anti-angiogenic treatment. METHODOLOGY/PRINCIPAL FINDINGS:Currently CECs are identified as positive for a nuclear binding antigen (DNA+), negative for the pan leukocyte marker CD45, and positive for CD31 and CD146. Following an approach recently validated in our laboratory, we investigated the expression of CD109 on CECs from the peripheral blood of healthy subject and cancer patients. The endothelial nature of these cells was validated by RT-PCR for the presence of m-RNA level of CDH5 (Ve-Cadherin) and CLDN5 (Claudin5), two endothelial specific transcripts. Before treatment, significantly higher levels of CD109+ CECs and viable CD109+CECs were found in breast cancer patients and glioblastoma patients compared to healthy controls, and their number significantly decreased after treatment. Higher levels of endothelial specific transcripts expressed in developing endothelial cells CLEC14a, TMEM204, ARHGEF15, GPR116, were observed in sorted CD109+CECs when compared to sorted CD146+CECs, suggesting that these genes can play an important role not only during embryogenesis but also in adult angiogenesis. Interestingly, mRNA levels of TEM8 (identified as Antrax Toxin Receptor1, Antrax1) were expressed in CD109+CECs+ but not in CD146+CECs. CONCLUSION:Taken together our results suggest that CD109 represent a rare population of circulating tumor endothelial cells, that play a potentially useful prognostic role in patients with glioblastoma. The role of CD109 expression in cancer vessel-specific endothelial cells deserves to be further investigated by gene expression studies.

Recent data suggest that circulating endothelial and progenitor cells (CECs and CEPs, respectively) may have predictive potential in cancer patients treated with bevacizumab, the antibody recognizing vascular endothelial growth factor (VEGF). Here we report on CECs and CEPs investigated in 68 patients affected by recurrent glioblastoma (rGBM) treated with bevacizumab and irinotecan and two Independent Datasets of rGBM patients respectively treated with bevacizumab alone (n=32, independent dataset A: IDA) and classical antiblastic chemotherapy (n=14, independent dataset B: IDB).rGBM patients with KPS ≥50 were treated until progression, as defined by MRI with RANO criteria. CECs expressing CD109, a marker of tumor endothelial cells, as well as other CEC and CEP subtypes, were investigated by six-color flow cytometry.A baseline count of CD109+ CEC higher than 41.1/ml (1(st) quartile) was associated with increased progression free survival (PFS; 20 versus 9 weeks, P=0.008) and overall survival (OS; 32 versus 23 weeks, P=0.03). Longer PFS (25 versus 8 weeks, P=0.02) and OS (27 versus 17 weeks, P=0.03) were also confirmed in IDA with CD109+ CECs higher than 41.1/ml but not in IDB. Patients treated with bevacizumab with or without irinotecan that were free from MRI progression after two months of treatment had significant decrease of CD109+ CECs: median PFS was 19 weeks; median OS 29 weeks. The presence of two non-contiguous lesions (distant disease) at baseline was an independent predictor of shorter PFS and OS (P

Embryologic and genetic evidence suggest a common origin of haematopoietic and endothelial lineages. In the murine embryo, recent studies indicate the presence of haemogenic endothelium and of a common haemato-endothelial precursor, the haemangioblast. Conversely, so far, little evidence supports the presence of haemogenic endothelium and haemangioblasts in later stages of development. Our studies indicate that human cord blood haematopoietic progenitors (CD34+45+144-), triggered by murine hepatocyte conditioned medium, differentiate into adherent proliferating endothelial precursors (CD144+CD105+CD146+CD31+CD45-) capable of functioning as haemogenic endothelium. These cells, proven to give rise to functional vasculature in vivo, if further instructed by haematopoietic growth factors, first switch to transitional CD144+45+ cells and then to haematopoietic cells. These results highlight the plasticity of haemato-endhothelial precursors in human post-natal life. Furthermore, these studies may provide highly enriched populations of human post-fetal haemogenic endothelium, paving the way for innovative projects at a basic and possibly clinical level.

Increasing evidence that a number of malignancies are characterised by tumour cell heterogeneity has recently been published, but there is still a lack of data concerning liver cancers. The aim of this study was to investigate and characterise tumour-propagating cell (TPC) compartments within human hepatocellular carcinoma (HCC).After long-term culture, we identified three morphologically different tumour cell populations in a single HCC specimen, and extensively characterised them by means of flow cytometry, fluorescence microscopy, karyotyping and microarray analyses, single cell cloning, and xenotransplantation in NOD/SCID/IL2Rγ/⁻ mice.The primary cell populations (hcc-1, -2 and -3) and two clones generated by means of limiting dilutions from hcc-1 (clone-1/7 and -1/8) differently expressed a number of tumour-associated stem cell markers, including EpCAM, CD49f, CD44, CD133, CD56, Thy-1, ALDH and CK19, and also showed different doubling times, drug resistance and tumorigenic potential. Moreover, we found that ALDH expression, in combination with CD44 or Thy-1 negativity or CD56 positivity identified subpopulations with a higher clonogenic potential within hcc-1, hcc-2 and hcc-3 primary cell populations, respectively. Karyotyping revealed the clonal evolution of the cell populations and clones within the primary tumour. Importantly, the primary tumour cell population with the greatest tumorigenic potential and drug resistance showed more chromosomal alterations than the others and contained clones with epithelial and mesenchymal features.Individual HCCs can harbor different self-renewing tumorigenic cell types expressing a variety of morphological and phenotypical markers, karyotypic evolution and different gene expression profiles. This suggests that the models of hepatic carcinogenesis should take into account TPC heterogeneity due to intratumour clonal evolution.

BackgroundGain-of-function of erythropoietin receptor (EPOR) mutations represent the major cause of primary hereditary polycythemia. EPOR is also found in non-erythroid tissues, although its physiological role is still undefined.Methodology/principal findingsWe describe a family with polycythemia due to a heterozygous mutation of the EPOR gene that causes a G-->T change at nucleotide 1251 of exon 8. The novel EPOR G1251T mutation results in the replacement of a glutamate residue by a stop codon at amino acid 393. Differently from polycythemia vera, EPOR G1251T CD34(+) cells proliferate and differentiate towards the erythroid phenotype in the presence of minimal amounts of EPO. Moreover, the affected individuals show a 20-fold increase of circulating endothelial precursors. The analysis of erythroid precursor membranes demonstrates a heretofore undescribed accumulation of the truncated EPOR, probably due to the absence of residues involved in the EPO-dependent receptor internalization and degradation. Mutated receptor expression in EPOR-negative cells results in EPOR and Stat5 phosphorylation. Moreover, patient erythroid precursors present an increased activation of EPOR and its effectors, including Stat5 and Erk1/2 pathway.Conclusions/significanceOur data provide an unanticipated mechanism for autosomal dominant inherited polycythemia due to a heterozygous EPOR mutation and suggest a regulatory role of EPO/EPOR pathway in human circulating endothelial precursors homeostasis.