Horizontal mitochondrial transfer as a novel bioenergetic tool for mesenchymal stromal/stem cells: molecular mechanisms and therapeutic potential in a variety of diseases

Intercellular mitochondrial transfer (MT) is a newly discovered form of cell-to-cell signalling involving the active incorporation of healthy mitochondria into stressed/injured recipient cells, contributing to the restoration of bioenergetic profile and cell viability, reduction of inflammatory processes and normalisation of calcium dynamics. Recent evidence has shown that MT can occur through multiple cellular structures and mechanisms: tunneling nanotubes (TNTs), via gap junctions (GJs), mediated by extracellular vesicles (EVs) and other mechanisms (cell fusion, mitochondrial extrusion and migrasome-mediated mitocytosis) and in different contexts, such as under physiological (tissue homeostasis and stemness maintenance) and pathological conditions (hypoxia, inflammation and cancer). As Mesenchimal Stromal/ Stem Cells (MSC)-mediated MT has emerged as a critical regulatory and restorative mechanism for cell and tissue regeneration and damage repair in recent years, its potential in stem cell therapy has received increasing attention. In particular, the potential therapeutic role of MSCs has been reported in several articles, suggesting that MSCs can enhance tissue repair after injury via MT and membrane vesicle release. For these reasons, in this review, we will discuss the different mechanisms of MSCs-mediated MT and therapeutic effects on different diseases such as neuronal, ischaemic, vascular and pulmonary diseases. Therefore, understanding the molecular and cellular mechanisms of MT and demonstrating its efficacy could be an important milestone that lays the foundation for future clinical trials.

Mesenchymal Stem Cells and Their Role in Neurodegenerative Diseases

Mesenchymal stem cells (MSCs) have garnered significant interest in the field of regenerative medicine for their ability to potentially treat various diseases, especially neurodegenerative disorders [...].

Analogies and Differences Between Dental Stem Cells: Focus on Secretome in Combination with Scaffolds in Neurological Disorders

Mesenchymal stem cells (MSCs) are well known for their beneficial effects, differentiation capacity and regenerative potential. Dental-derived MSCs (DSCs) are more easily accessible and have a non-invasive isolation method rather than MSCs isolated from other sources (umbilical cord, bone marrow, and adipose tissue). In addition, DSCs appear to have a relevant neuro-regenerative potential due to their neural crest origin. However, it is now known that the beneficial effects of MSCs depend, at least in part, on their secretome, referring to all the bioactive molecules (neurotrophic factors) released in the conditioned medium (CM) or in the extracellular vesicles (EVs) in particular exosomes (Exos). In this review, we described the similarities and differences between various DSCs. Our focus was on the secretome of DSCs and their applications in cell therapy for neurological disorders. For neuro-regenerative purposes, the secretome of different DSCs has been tested. Among these, the secretome of dental pulp stem cells and stem cells from human exfoliated deciduous teeth have been the most widely studied. Both CM and Exos obtained from DSCs have been shown to promote neurite outgrowth and neuroprotective effects as well as their combination with scaffold materials (to improve their functional integration in the tissue). For these reasons, the secretome obtained from DSCs in combination with scaffold materials may represent a promising tissue engineering approach for neuroprotective and neuro-regenerative treatments.

Lipid rafts mediate multilineage differentiation of human dental pulp-derived stem cells (DPSCs)

Cell outer membranes contain glycosphingolipids and protein receptors, which are integrated into glycoprotein domains, known as lipid rafts, which are involved in a variety of cellular processes, including receptor-mediated signal transduction and cellular differentiation process. In this study, we analyzed the lipidic composition of human Dental Pulp-Derived Stem Cells (DPSCs), and the role of lipid rafts during the multilineage differentiation process. The relative quantification of lipid metabolites in the organic fraction of DPSCs, performed by Nuclear Magnetic Resonance (NMR) spectroscopy, showed that mono-unsaturated fatty acids (MUFAs) were the most representative species in the total pool of acyl chains, compared to polyunsatured fatty acids (PUFAs). In addition, the stimulation of DPSCs with different culture media induces a multilineage differentiation process, determining changes in the gangliosides pattern. To understand the functional role of lipid rafts during multilineage differentiation, DPSCs were pretreated with a typical lipid raft affecting agent (MβCD). Subsequently, DPSCs were inducted to differentiate into osteoblast, chondroblast and adipoblast cells with specific media. We observed that raft-affecting agent MβCD prevented AKT activation and the expression of lineage-specific mRNA such as OSX, PPARγ2, and SOX9 during multilineage differentiation. Moreover, this compound significantly prevented the tri-lineage differentiation induced by specific stimuli, indicating that lipid raft integrity is essential for DPSCs differentiation. These results suggest that lipid rafts alteration may affect the signaling pathway activated, preventing multilineage differentiation.

Different Chronic Stress Paradigms Converge on Endogenous TDP43 Cleavage and Aggregation

The TAR-DNA binding protein (TDP43) is a nuclear protein whose cytoplasmic inclusions are hallmarks of Amyotrophic Lateral Sclerosis (ALS). Acute stress in cells causes TDP43 mobilization to the cytoplasm and its aggregation through different routes. Although acute stress elicits a strong phenotype, is far from recapitulating the years-long aggregation process. We applied different chronic stress protocols and described TDP43 aggregation in a human neuroblastoma cell line by combining solubility assays, thioflavin-based microscopy and flow cytometry. This approach allowed us to detect, for the first time to our knowledge in vitro, the formation of 25 kDa C-terminal fragment of TDP43, a pathogenic hallmark of ALS. Our results indicate that chronic stress, compared to the more common acute stress paradigm, better recapitulates the cell biology of TDP43 proteinopathies. Moreover, we optimized a protocol for the detection of bona fide prions in living cells, suggesting that TDP43 may form amyloids as a stress response.

10th Anniversary of Biomedicines-Advances in Mesenchymal Stem Cells

Mesenchymal stromal cells (MSCs) are non-specialized adult stem cells (ASCs), cells that reproduce to provide specific cytotypes [...].

Mitotic phosphorylation of Tau/MAPT modulates cell cycle progression in prostate cancer cells

PURPOSE

Tau/MAPT (microtubule associated protein tau) protein is actively studied for the pathologic consequences of its aberrant proteostasis in central nervous system leading to neurodegenerative diseases. Besides its ability to generate insoluble toxic oligomers, Tau homeostasis has attracted attention for its involvement in the formation of the mitotic spindle. This evidence, in association with the description of Tau expression in extra-neuronal tissues, and mainly in cancer tissues, constitutes the rationale for a more in-depth investigation of Tau role also in neoplastic diseases.

METHODS

In our study, we investigated the expression of phosphorylated Tau in prostate cancer cell lines with particular focus on the residue Thr231 present in microtubule binding domain.

RESULTS

The analysis of prostate cancer cells synchronized with nocodazole demonstrated that the expression of Tau protein phosphorylated at residue Thr231 is restricted to G2/M cell cycle phase. The phosphorylated form was unable to bind tubulin and it does not localize on mitotic spindle. As demonstrated by the use of specific inhibitors, the phosphorylation status of Tau is under the direct control of cdk5 and PP2A, while cdk1 activation was able to exert an indirect control. These mechanisms were also active in cells treated with docetaxel, where counteracting the expression of the dephosphorylated form, by kinase inhibition or protein silencing, determined resistance to drug toxicity.

CONCLUSIONS

We hypothesize that phosphorylation status of Tau is a key marker for G2/M phase in prostate cancer cells and that the forced modulation of Tau phosphorylation can interfere with the capacity of cell to efficiently progress through G2/M phase.

Role of a Novel Heparanase Inhibitor on the Balance between Apoptosis and Autophagy in U87 Human Glioblastoma Cells

BACKGROUND

Heparanase (HPSE) is an endo-β-glucuronidase that cleaves heparan sulfate side chains, leading to the disassembly of the extracellular matrix, facilitating cell invasion and metastasis dissemination. In this research, we investigated the role of a new HPSE inhibitor, RDS 3337, in the regulation of the autophagic process and the balance between apoptosis and autophagy in U87 glioblastoma cells.

METHODS

After treatment with RDS 3337, cell lysates were analyzed for autophagy and apoptosis-related proteins by Western blot.

RESULTS

We observed, firstly, that LC3II expression increased in U87 cells incubated with RDS 3337, together with a significant increase of p62/SQSTM1 levels, indicating that RDS 3337 could act through the inhibition of autophagic-lysosomal flux of LC3-II, thereby leading to accumulation of lipidated LC3-II form. Conversely, the suppression of autophagic flux could activate apoptosis mechanisms, as revealed by the activation of caspase 3, the increased level of cleaved Parp1, and DNA fragmentation.

CONCLUSIONS

These findings support the notion that HPSE promotes autophagy, providing evidence that RDS 3337 blocks autophagic flux. It indicates a role for HPSE inhibitors in the balance between apoptosis and autophagy in U87 human glioblastoma cells, suggesting a potential role for this new class of compounds in the control of tumor growth progression.

The Importance of Stem Cells Isolated from Human Dental Pulp and Exfoliated Deciduous Teeth as Therapeutic Approach in Nervous System Pathologies

Despite decades of research, no therapies are available to halt or slow down the course of neuro-degenerative disorders. Most of the drugs developed to fight neurodegeneration are aimed to alleviate symptoms, but none has proven adequate in altering the course of the pathologies. Cell therapy has emerged as an intriguing alternative to the classical pharmacological approach. Cell therapy consists of the transplantation of stem cells that can be obtained from various embryonal and adult tissues. Whereas the former holds notable ethical issue, adult somatic stem cells can be obtained without major concerns. However, most adult stem cells, such as those derived from the bone marrow, are committed toward the mesodermal lineage, and hence need to be reprogrammed to induce the differentiation into the neurons. The discovery of neural crest stem cells in the dental pulp, both in adults' molar and in baby teeth (dental pulp stem cells and stem cells from human exfoliated deciduous teeth, respectively) prompted researchers to investigate their utility as therapy in nervous system disorders. In this review, we recapitulate the advancements on the application of these stem cells in preclinical models of neurodegenerative diseases, highlighting differences and analogies in their maintenance, differentiation, and potential clinical application.

Dental Pulp Stem Cells (DPSCs) and Tissue Regeneration: Mechanisms Mediated by Direct, Paracrine, or Autocrine Effects

Among mesenchymal stem cells, dental pulp stem cells (DPSCs) were discovered most recently [...].

Gangliosides and Their Role in Multilineage Differentiation of Mesenchymal Stem Cells

Gangliosides (GGs) are a glycolipid class present on Mesenchymal Stem Cells (MSCs) surfaces with a critical appearance role in stem cell differentiation, even though their mechanistic role in signaling and differentiation remains largely unknown. This review aims to carry out a critical analysis of the predictive role of gangliosides as specific markers of the cellular state of undifferentiated and differentiated MSCs, towards the osteogenic, chondrogenic, neurogenic, and adipogenic lineage. For this reason, we analyzed the role of GGs during multilineage differentiation processes of several types of MSCs such as Umbilical Cord-derived MSCs (UC-MSCs), Bone Marrow-derived MSCs (BM-MSCs), Dental Pulp derived MSCs (DPSCs), and Adipose derived MSCs (ADSCs). Moreover, we examined the possible role of GGs as specific cell surface markers to identify or isolate specific stem cell isotypes and their potential use as additional markers for quality control of cell-based therapies.

Anticancer effects of ABTL0812, a clinical stage drug inducer of autophagy-mediated cancer cell death, in glioblastoma models

BACKGROUND

Glioblastoma multiforme (GBM) is the most malignant adult brain tumor. Current standard of care treatments have very limited efficacy, being the patients´ overall survival 14 months and the 2-year survival rate less than 10%. Therefore, the treatment of GBM is an urgent unmet clinical need.

METHODS

The aim of this study was to investigate in vitro and in vivo the potential of ABTL0812, an oral anticancer compound currently in phase II clinical stage, as a novel therapy for GBM.

RESULTS

We showed that ABTL0812 inhibits cell proliferation in a wide panel of GBM cell lines and patient-derived glioblastoma stem cells (GSCs) with half maximal inhibitory concentrations (IC50s) ranging from 15.2 µM to 46.9 µM. Additionally, ABTL0812 decreased GSCs neurosphere formation. GBM cells aggressiveness is associated with a trans-differentiation process towards a less differentiated phenotype known as proneural to mesenchymal transition (PMT). ABTL0812 was shown to revert PMT and induce cell differentiation to a less malignant phenotype in GBM cell lines and GSCs, and consequently reduced cell invasion. As previously shown in other cancer types, we demonstrated that the molecular mechanism of action of ABTL0812 in glioblastoma involves the inhibition of Akt/mTORC1 axis by overexpression of TRIB3, and the activation of endoplasmic reticulum (ER) stress/unfolded protein response (UPR). Both actions converge to induce autophagy-mediated cell death. ABTL0812 anticancer efficacy was studied in vivo using subcutaneous and orthotopic intra-brain xenograft tumor models. We demonstrated that ABTL0812 impairs tumor growth and increases disease-free survival and overall survival of mice. Furthermore, the histological analysis of tumors indicated that ABTL0812 decreases angiogenesis. Finally, we investigated the combination of ABTL0812 with the standard of care treatments for GBM radiotherapy and temozolomide in an orthotopic model, detecting that ABTL0812 potentiates the efficacy of both treatments and that the strongest effect is obtained with the triple combination of ABTL0812+radiotherapy+temozolomide.

CONCLUSIONS

Overall, the present study demonstrated the anticancer efficacy of ABTL0812 as single agent and in combination with the GBM standard of care treatments in models of glioblastoma and supports the clinical investigation of ABTL0812 as a potential novel therapy for this aggressive brain tumor type.

Abstract 6307: The botanical drug PBI-05204, a supercritical CO₂ extract of Nerium oleander, augments the antitumor efficacy of radiotherapy in treatment of human glioblastoma

Glioblastoma multiforme (GBM) is the most common as well as one of the most malignant types of brain cancer. Despite progress in development of novel therapies for the treatment of GBM, it remains largely incurable with a poor prognosis and a very low life expectancy. Recent studies have shown that oleandrin, a unique cardiac glycoside from Nerium oleander, as well as defined extract (PBI-05204) that contains this molecule, inhibit growth of human glioblastoma, and modulate glioblastoma patient-derived stem cell-renewal properties. The present study aimed to investigate the radiosensitization of PBI-05204 in glioblastoma using both in vitro and in vivo cancer models as well as to explore the potential mechanism of actions in GBM. The radiosensitizing effect of PBI-05204 was assessed against human GBM U87MG, U251, T98G and A172 cell lines as well as their relevant xenograft and orthotopic models. The induction of apoptosis, DNA damage and repair of DNA double strand breaks were assessed with determination of caspase 3 and 9 protein expression, DNA laddering, protein expression of rH2AX, Ku70, DNA-PKcs, and RAD51 as well as a Comet Assay. PBI-05204 treatment leads to an increased in vitro sensitivity of GBM cells, including U87MG, U251, T98G and A172 cells, to radiotherapy (RT) in which the main mechanisms are the transition from autophagy to apoptosis and enhanced DNA damage evidenced by increased expression of γH2AX. Additionally, relative increased expression of Ku70, DNA-PKcs and RAD51 due to RT were reduced by PBI-05204 in U87MG and U251 cells, suggesting PBI-05204 lessened RT mediated DNA repair. PBI-05204 significantly enhanced the RT mediated inhibition of tumor growth by 4.7-, 2.1- and 2.2-fold in U87MG, U251 and T98G xenograft models, respectively. The combination of RT and PBI-05204 showed a significantly enhancement of disease-free survival to 103.0 ± 63.2 days compared to the control group (p < 0.001) which was 3-fold longer than that of RT only group. Collectively, these results reveal that PBI-05204 enhances antitumor activity of RT in preclinical/murine models of human GBM. Given the fact that PBI-05204 has already been examined in Phase I and II clinical trials for cancer patients, its efficacy when combined with standard-of-care radiotherapy regimens in GBM should be explored in future clinical trials of this difficult to treat brain cancer.

Citation Format: Alessandro Colapietro, Peiying Yang, Alessandra Rosetti, Andrea Mancini, Flora Vital, Stefano Martellucci, Francesco Marampon, Vincenzo Mattei, Giovanni Luca Gravina, Robert Newman, Claudio Festuccia. The botanical drug PBI-05204, a supercritical CO₂ extract of Nerium oleander, augments the antitumor efficacy of radiotherapy in treatment of human glioblastoma [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 6307.

Antioxidant Properties of Cerium Oxide Nanoparticles Prevent Retinal Neovascular Alterations In Vitro and In Vivo

In this study, we investigated whether cerium oxide nanoparticles (CeO₂-NPs), a promising antioxidant nanomaterial, may contrast retinal vascular alterations induced by oxidative damage in vitro and in vivo. For the in vivo experiments, the light damage (LD) animal model of Age-Related Macular Degeneration (AMD) was used and the CeO₂-NPs were intravitreally injected. CeO₂-NPs significantly decreased vascular endothelial growth factor (VEGF) protein levels, reduced neovascularization in the deep retinal plexus, and inhibited choroidal sprouting into the photoreceptor layer. The in vitro experiments were performed on human retinal pigment epithelial (ARPE-19) cells challenged with H₂O₂; we demonstrated that CeO₂-NPs reverted H₂O₂-induced oxidative stress-dependent effects on this cell model. We further investigated the RPE-endothelial cells interaction under oxidative stress conditions in the presence or absence of CeO₂-NPs through two experimental paradigms: (i) treatment of human umbilical vein endothelial cells (HUVECs) with conditioned media from ARPE-19 cells, and (ii) coculture of ARPE-19 and HUVECs. In both experimental conditions, CeO₂-NPs were able to revert the detrimental effect of H₂O₂ on angiogenesis in vitro by realigning the level of tubule formation to that of the control. Altogether, our results indicate, for the first time, that CeO₂-NPs can counteract retinal neovascularization and may be a new therapeutic strategy for the treatment of wet AMD.

The Botanical Drug PBI-05204, a Supercritical CO2 Extract of Nerium Oleander, Is Synergistic With Radiotherapy in Models of Human Glioblastoma

Glioblastoma multiforme (GBM) is the most common as well as one of the most malignant types of brain cancer. Despite progress in development of novel therapies for the treatment of GBM, it remains largely incurable with a poor prognosis and a very low life expectancy. Recent studies have shown that oleandrin, a unique cardiac glycoside from Nerium oleander, as well as a defined extract (PBI-05204) that contains this molecule, inhibit growth of human glioblastoma, and modulate glioblastoma patient-derived stem cell-renewal properties. Here we demonstrate that PBI-05204 treatment leads to an increase in vitro in the sensitivity of GBM cells to radiation in which the main mechanisms are the transition from autophagy to apoptosis, enhanced DNA damage and reduced DNA repair after radiotherapy (RT) administration. The combination of PBI-05204 with RT was associated with reduced tumor progression evidenced by both subcutaneous as well as orthotopic implanted GBM tumors. Collectively, these results reveal that PBI-05204 enhances antitumor activity of RT in preclinical/murine models of human GBM. Given the fact that PBI-05204 has already been examined in Phase I and II clinical trials for cancer patients, its efficacy when combined with standard-of-care radiotherapy regimens in GBM should be explored.

ATX-101, a Peptide Targeting PCNA, Has Antitumor Efficacy Alone or in Combination with Radiotherapy in Murine Models of Human Glioblastoma

Cell proliferation requires the orchestrated actions of a myriad of proteins regulating DNA replication, DNA repair and damage tolerance, and cell cycle. Proliferating cell nuclear antigen (PCNA) is a master regulator which interacts with multiple proteins functioning in these processes, and this makes PCNA an attractive target in anticancer therapies. Here, we show that a cell-penetrating peptide containing the AlkB homolog 2 PCNA-interacting motif (APIM), ATX-101, has antitumor activity in a panel of human glioblastoma multiforme (GBM) cell lines and patient-derived glioma-initiating cells (GICs). Their sensitivity to ATX-101 was not related to cellular levels of PCNA, or p53, PTEN, or MGMT status. However, ATX-101 reduced Akt/mTOR and DNA-PKcs signaling, and a correlation between high Akt activation and sensitivity for ATX-101 was found. ATX-101 increased the levels of γH2AX, DNA fragmentation, and apoptosis when combined with radiotherapy (RT). In line with the in vitro results, ATX-101 strongly reduced tumor growth in two subcutaneous xenografts and two orthotopic GBM models, both as a single agent and in combination with RT. The ability of ATX-101 to sensitize cells to RT is promising for further development of this compound for use in GBM.

Prions and Neurodegenerative Diseases: A Focus on Alzheimer's Disease

Specific protein misfolding and aggregation are mechanisms underlying various neurodegenerative diseases such as prion disease and Alzheimer's disease (AD). The misfolded proteins are involved in prions, amyloid-β (Aβ), tau, and α-synuclein disorders; they share common structural, biological, and biochemical characteristics, as well as similar mechanisms of aggregation and self-propagation. Pathological features of AD include the appearance of plaques consisting of deposition of protein Aβ and neurofibrillary tangles formed by the hyperphosphorylated tau protein. Although it is not clear how protein aggregation leads to AD, we are learning that the cellular prion protein (PrPC) plays an important role in the pathogenesis of AD. Herein, we first examined the pathogenesis of prion and AD with a focus on the contribution of PrPC to the development of AD. We analyzed the mechanisms that lead to the formation of a high affinity bond between Aβ oligomers (AβOs) and PrPC. Also, we studied the role of PrPC as an AβO receptor that initiates an AβO-induced signal cascade involving mGluR5, Fyn, Pyk2, and eEF2K linking Aβ and tau pathologies, resulting in the death of neurons in the central nervous system. Finally, we have described how the PrPC-AβOs interaction can be used as a new potential therapeutic target for the treatment of PrPC-dependent AD.

Multiple Antitumor Molecular Mechanisms Are Activated by a Fully Synthetic and Stabilized Pharmaceutical Product Delivering the Active Compound Sulforaphane (SFX-01) in Preclinical Model of Human Glioblastoma

Frequent relapses and therapeutic resistance make the management of glioblastoma (GBM, grade IV glioma), extremely difficult. Therefore, it is necessary to develop new pharmacological compounds to be used as a single treatment or in combination with current therapies in order to improve their effectiveness and reduce cytotoxicity for non-tumor cells. SFX-01 is a fully synthetic and stabilized pharmaceutical product containing the α-cyclodextrin that delivers the active compound 1-isothiocyanato-4-methyl-sulfinylbutane (SFN) and maintains biological activities of SFN. In this study, we verified whether SFX-01 was active in GBM preclinical models. Our data demonstrate that SFX-01 reduced cell proliferation and increased cell death in GBM cell lines and patient-derived glioma initiating cells (GICs) with a stem cell phenotype. The antiproliferative effects of SFX-01 were associated with a reduction in the stemness of GICs and reversion of neural-to-mesenchymal trans-differentiation (PMT) closely related to epithelial-to-mesenchymal trans-differentiation (EMT) of epithelial tumors. Commonly, PMT reversion decreases the invasive capacity of tumor cells and increases the sensitivity to pharmacological and instrumental therapies. SFX-01 induced caspase-dependent apoptosis, through both mitochondrion-mediated intrinsic and death-receptor-associated extrinsic pathways. Here, we demonstrate the involvement of reactive oxygen species (ROS) through mediating the reduction in the activity of essential molecular pathways, such as PI3K/Akt/mTOR, ERK, and STAT-3. SFX-01 also reduced the in vivo tumor growth of subcutaneous xenografts and increased the disease-free survival (DFS) and overall survival (OS), when tested in orthotopic intracranial GBM models. These effects were associated with reduced expression of HIF1α which, in turn, down-regulates neo-angiogenesis. So, SFX-01 may have potent anti-glioma effects, regulating important aspects of the biology of this neoplasia, such as hypoxia, stemness, and EMT reversion, which are commonly activated in this neoplasia and are responsible for therapeutic resistance and glioma recurrence. SFX-01 deserves to be considered as an emerging anticancer agent for the treatment of GBM. The possible radio- and chemo sensitization potential of SFX-01 should also be evaluated in further preclinical and clinical studies.

Exposure Profile to Traffic Related Pollution in Pediatric Age: A Biomonitoring Study

The aim of this study was to trace an exposure profile to traffic-derived pollution during pediatric age. For this purpose, two biomonitoring campaigns for the determination of urinary (u-) methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), and diisopropyl ether (DIPE) were carried out in two different periods of the year (summer 2017 and winter 2018), among a large sample of healthy children (n = 736; 5–11 years old) living in rural and urban areas in central Italy. The quantification of u-MTBE, u-ETBE, u-TAME, and u-DIPE was performed by HS-SPME-GC/MS technique and information on participants was collected by a questionnaire. u-DIPE concentrations resulted always under the LOQ. u-TAME mean levels were similar in both seasons (18.7 ng L⁻¹ in summer vs. 18.9 ng L⁻¹ in winter), while u-MTBE and u-ETBE levels were, respectively, 69.9 and 423.5 ng L⁻¹ (summer) and 53.3 and 66.2 ng L⁻¹ (winter). Main predictors of urinary excretion resulted the time spent in motor vehicles, being male and younger.

Regenerative Potential of DPSCs and Revascularization: Direct, Paracrine or Autocrine Effect?

A new source of mesenchymal stem cells has recently been discovered, the so-called dental pulp derived stem cells (DPSCs) which therefore could represent potentially tools for regenerative medicine. DPSC originate from the neural crest and are physiologically involved in dentin homeostasis; moreover, they contribute to bone remodeling and differentiation into several tissues including cartilage, bone, adipose and nervous tissues. DPSCs have also been shown to influence the angiogenesis process, for example through the release of secretory factors or by differentiating into vascular and/or perivascular cells. Angiogenesis, that has a pivotal role in tissue regeneration and repair, is defined as the formation of new vessels from preexisting vessels and is mediated by mutual and reciprocal interactions between endothelial cells and perivascular cells. It is also known that co-cultures of perivascular and endothelial cells (ECs) can form a vascular network in vitro and also in vivo. Since DPSCs seem to have characteristics similar to pericytes, understanding the possible mechanism of interaction between DPSCs and ECs during neo-angiogenesis is dramatically important for the development of advanced clinical application in the field of regeneration.

The Role of Cardiolipin as a Scaffold Mitochondrial Phospholipid in Autophagosome Formation: In Vitro Evidence

Cardiolipin (CL) is a hallmark phospholipid localized within the inner mitochondrial membrane. Upon several mitochondrial stress conditions, CL is translocated to specialized platforms, where it may play a role in signaling events to promote mitophagy and apoptosis. Recent studies characterized the molecular composition of MAM-associated lipid microdomains and their implications in regulating the autophagic process. In this study we analyzed the presence of CL within MAMs following autophagic stimulus and the possible implication of raft-like microdomains enriched in CL as a signaling platform in autophagosome formation. Human 2FTGH fibroblasts and SKNB-E-2 cells were stimulated under nutrient deprivation with HBSS. MAM fraction was obtained by an ultracentrifugation procedure and analyzed by HPTLC immunostaining. CL interactions with mitofusin2 (MFN2), calnexin (CANX) and AMBRA1 were analyzed by scanning confocal microscopy and coimmunoprecipitation. The analysis revealed that CL accumulates in MAMs fractions following autophagic stimulus, where it interacts with MFN2 and CANX. It associates with AMBRA1, which in turn interacts with BECN1 and WIPI1. This study demonstrates that CL is present in MAM fractions following autophagy triggering and interacts with the multimolecular complex (AMBRA1/BECN1/WIPI1) involved in autophagosome formation. It may have both structural and functional implications in the pathophysiology of neurodegenerative disease(s).

Targeting Lipid Rafts as a Strategy Against Coronavirus

Lipid rafts are functional membrane microdomains containing sphingolipids, including gangliosides, and cholesterol. These regions are characterized by highly ordered and tightly packed lipid molecules. Several studies revealed that lipid rafts are involved in life cycle of different viruses, including coronaviruses. Among these recently emerged the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The main receptor for SARS-CoV-2 is represented by the angiotensin-converting enzyme-2 (ACE-2), although it also binds to sialic acids linked to host cell surface gangliosides. A new type of ganglioside-binding domain within the N-terminal portion of the SARS-CoV-2 spike protein was identified. Lipid rafts provide a suitable platform able to concentrate ACE-2 receptor on host cell membranes where they may interact with the spike protein on viral envelope. This review is focused on selective targeting lipid rafts components as a strategy against coronavirus. Indeed, cholesterol-binding agents, including statins or methyl-β-cyclodextrin (MβCD), can affect cholesterol, causing disruption of lipid rafts, consequently impairing coronavirus adhesion and binding. Moreover, these compounds can block downstream key molecules in virus infectivity, reducing the levels of proinflammatory molecules [tumor necrosis factor alpha (TNF-α), interleukin (IL)-6], and/or affecting the autophagic process involved in both viral replication and clearance. Furthermore, cyclodextrins can assemble into complexes with various drugs to form host-guest inclusions and may be used as pharmaceutical excipients of antiviral compounds, such as lopinavir and remdesivir, by improving bioavailability and solubility. In conclusion, the role of lipid rafts-affecting drugs in the process of coronavirus entry into the host cells prompts to introduce a new potential task in the pharmacological approach against coronavirus.

What Is Known about Theragnostic Strategies in Colorectal Cancer

Despite the paradigmatic shift occurred in recent years for defined molecular subtypes in the metastatic setting treatment, colorectal cancer (CRC) still remains an incurable disease in most of the cases. Therefore, there is an urgent need for new tools and biomarkers for both early tumor diagnosis and to improve personalized treatment. Thus, liquid biopsy has emerged as a minimally invasive tool that is capable of detecting genomic alterations from primary or metastatic tumors, allowing the prognostic stratification of patients, the detection of the minimal residual disease after surgical or systemic treatments, the monitoring of therapeutic response, and the development of resistance, establishing an opportunity for early intervention before imaging detection or worsening of clinical symptoms. On the other hand, preclinical and clinical evidence demonstrated the role of gut microbiota dysbiosis in promoting inflammatory responses and cancer initiation. Altered gut microbiota is associated with resistance to chemo drugs and immune checkpoint inhibitors, whereas the use of microbe-targeted therapies including antibiotics, pre-probiotics, and fecal microbiota transplantation can restore response to anticancer drugs, promote immune response, and therefore support current treatment strategies in CRC. In this review, we aim to summarize preclinical and clinical evidence for the utilization of liquid biopsy and gut microbiota in CRC.

Urinary Mercury Levels and Predictors of Exposure among a Group of Italian Children

Urinary mercury (Hg) levels are suitable to assess long-term exposure to both elemental and inorganic Hg. In this study, the urinary Hg levels of 250 children (aged 6–11 years) from three areas with different anthropogenic impacts in the Rieti province, central Italy, were assessed. The Hg concentrations were in the range of 0.04–2.18 µg L⁻¹ with a geometric mean equal to 0.18 µg L⁻¹ [95% confidence interval (CI), 0.17–0.20 µg L⁻¹] or 0.21 µg g⁻¹ creatinine (95% CI, 0.19–0.23 µg g⁻¹ creatinine), and a reference value calculated as 95th percentile of 0.53 µg L⁻¹ (95% CI, 0.44–0.73 µg L⁻¹) or 0.55 µg g⁻¹ creatinine (95% CI, 0.50–0.83 µg g⁻¹ creatinine). In all cases, urinary Hg data were below the HBM-I values (7 µg L⁻¹ or 5 µg g⁻¹ creatinine) established for urine, while the 95th percentile was above the German Human Biomonitoring Commission’s RV95 (0.4 µg L⁻¹) set for children without amalgam fillings. A significant correlation (p < 0.05) was found between creatinine-corrected results and residence area, with higher urinary Hg levels in children living in the industrial area. Multiple linear regression analysis showed that creatinine was the main predictor of urinary Hg.

The Botanical Drug PBI-05204, a Supercritical CO2 Extract of Nerium Oleander, Inhibits Growth of Human Glioblastoma, Reduces Akt/mTOR Activities, and Modulates GSC Cell-Renewal Properties

Glioblastoma multiform (GBM) is the most common primary glial tumor resulting in very low patient survival despite current extensive therapeutic efforts. Emerging evidence suggests that more effective treatments are required to overcome tumor heterogeneity, drug resistance and a complex tumor-supporting microenvironment. PBI-05204 is a specifically formulated botanical drug consisting of a modified supercritical C0₂ extract of Nerium oleander that has undergone both phase I and phase II clinical trials in the United States for treatment of patients with a variety of advanced cancers. The present study was designed to investigate the antitumor efficacy of this botanical drug against glioblastoma using both in vitro and in vivo cancer models as well as exploring efficacy against glioblastoma stem cells. All three human GBM cell lines, U87MG, U251, and T98G, were inhibited by PBI-05204 in a concentration dependent manner that was characterized by induction of apoptosis as evidenced by increased ANNEXIN V staining and caspase activities. The expression of proteins associated with both Akt and mTOR pathway was suppressed by PBI-05240 in all treated human GBM cell lines. PBI-05204 significantly suppressed U87 spheroid formation and the expression of important stem cell markers such as SOX2, CD44, and CXCR4. Oral administration of PBI-05204 resulted in a dose-dependent inhibition of U87MG, U251, and T98G xenograft growth. Additionally, PBI-05204–treated mice carrying U87-Luc cells as an orthotropic model exhibited significantly delayed onset of tumor proliferation and significantly increased overall survival. Immunohistochemical staining of xenograft derived tumor sections revealed dose-dependent declines in expression of Ki67 and CD31 positive stained cells but increased TUNEL staining. PBI-05204 represents a novel therapeutic botanical drug approach for treatment of glioblastoma as demonstrated by significant responses with in vivo tumor models. Both in vitro cell culture and immunohistochemical studies of tumor tissue suggest drug induction of tumor cell apoptosis and inhibition of PI3k/mTOR pathways as well as cancer stemness. Given the fact that PBI-05204 has already been examined in phase I and II clinical trials for cancer patients, its efficacy when combined with standard of care chemotherapy and radiotherapy should be explored in future clinical trials of this difficult to treat brain cancer.

A Cross-Sectional Study on Benzene Exposure in Pediatric Age and Parental Smoking Habits at Home

After the introduction of the smoke-free legislation, household smoking has become the major source of environmental tobacco smoke (ETS) exposure for children. In our previous research, we found a strong association between urinary unmodified benzene (u-UB) levels and passive smoking exposure related to the home smoking policies (HSP). The aim of the study is to further investigate the impacts of several factors on ETS-exposure in childhood by using u-UB as tobacco-related carcinogen biomarker of exposure. Two cross-sectional studies were performed on the same target population of our previous research, in summer and winter season of the years 2017 and 2018, respectively. A questionnaire and a head space-solid phase micro-extraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS) analytical method were used as investigative procedures. The improvement found in smoking habits, when compared to our previous surveys, reduced the levels of u-UB in children. However, significant differences related to the high number of smokers and smoked cigarettes, in total and at home, still persist. These differences are more relevant in the winter season. Finally, the only effective way for making homes completely smokefree is to develop public health policies for encouraging people to quit or drastically reduce smoking.

LRP6 mediated signal transduction pathway triggered by tissue plasminogen activator acts through lipid rafts in neuroblastoma cells

LDL receptor-related proteins 6 (LRP6) is a type I transmembrane receptor (C-terminus in cytosol), which appears to be essential in numerous biological processes, since it is an essential co-receptor of Wnt ligands for canonical β-catenin dependent signal transduction. It was shown that tissue plasminogen activator (tPA), physically interacting with LRP6, induces protein phosphorylation, which may have large implication in the regulation of neural processes. In this investigation we analyzed whether LRP6 is associated with lipid rafts following tPA triggering in neuroblastoma cells and the role of raft integrity in LRP6 cell signaling. Sucrose gradient separation revealed that phosphorylated LRP6 was mainly, but not exclusively present in lipid rafts; this enrichment became more evident after triggering with tPA. In these microdomains LRP6 is strictly associated with ganglioside GM1, a paradigmatic component of these plasma membrane compartments, as revealed by coimmunoprecipitation experiments. As expected, tPA triggering induced LRP6 phosphorylation, which was independent of LRP1, as revealed by knockdown experiments by siRNA, but strictly dependent on raft integrity. Moreover, tPA induced β-catenin phosphorylation was also significantly prevented by previous pretreatment with methyl-β-cyclodextrin. Our results demonstrate that LRP6 mediated signal transduction pathway triggered by tPA acts through lipid rafts in neuroblastoma cells. These findings introduce an additional task for identifying new molecular target(s) of pharmacological agents. Indeed, these data, pointing to the key role of lipid rafts in tPA triggered signaling involving β-catenin, may have pharmacological implications, suggesting that cyclodextrins, and potentially other drugs, such as statins, may represent an useful tool.

A multimolecular signaling complex including PrPC and LRP1 is strictly dependent on lipid rafts and is essential for the function of tissue plasminogen activator

Prion protein (PrP^C ) localizes stably in lipid rafts microdomains and is able to recruit downstream signal transduction pathways by the interaction with promiscuous partners. Other proteins have the ability to occasionally be recruited to these specialized membrane areas, within multimolecular complexes. Among these, we highlight the presence of the low-density lipoprotein receptor-related protein 1 (LRP1), which was found localized transiently in lipid rafts, suggesting a different function of this receptor that through lipid raft becomes able to activate a signal transduction pathway triggered by specific ligands, including Tissue plasminogen activator (tPA). Since it has been reported that PrP^C participates in the tPA-mediated plasminogen activation, in this study, we describe the role of lipid rafts in the recruitment and activation of downstream signal transduction pathways mediated by the interaction among tPA, PrP^C and LRP1 in human neuroblastoma SK-N-BE2 cell line. Co-immunoprecipitation analysis reveals a consistent association between PrP^C and GM1, as well as between LRP1 and GM1, indicating the existence of a glycosphingolipid-enriched multimolecular complex. In our cell model, knocking-down PrP^C by siRNA impairs ERK phosphorylation induced by tPA. Moreover the alteration of the lipidic milieu of lipid rafts, perturbing the physical/functional interaction between PrP^C and LRP1, inhibits this response. We show that LRP1 and PrP^C , following tPA stimulation, may function as a system associated with lipid rafts, involved in receptor-mediated neuritogenic pathway. We suggest this as a multimolecular signaling complex, whose activity depends strictly on the integrity of lipid raft and is involved in the neuritogenic signaling.

Further Insights on Predictors of Environmental Tobacco Smoke Exposure during the Pediatric Age

Background: The smoking ban in public places has reduced Environmental Tobacco Smoke (ETS) exposure for non-smokers, but despite this, domestic environments still remain places at high risk of exposure, and, today, about 40% of children worldwide are exposed to ETS at home. The aims of the study are to investigate the contribution of several factors on ETS exposure among a group of Italian children and to evaluate the changes in smoking precautions adopted at home when the smoker is the mother, the father, or both parents, respectively. Methods: A cross-sectional study was performed on a sample of 519 Italian schoolchildren. Information was collected via a questionnaire. Results: 41.4% of the participants lived with at least one smoker. Almost half of the children exposed to ETS lived with one or more smokers who do not observe any home smoking ban. Lower maternal or paternal educational levels significantly increase the risk of ETS exposure at home and the "worst case" is represented by both parents who smoke. Conclusions: More effective preventive interventions are needed to protect children from ETS exposure. Some interventions should be specifically dedicated to smokers with a low educational level and to mothers that smoke.

Autophagy induces protein carbamylation in fibroblast-like synoviocytes from patients with rheumatoid arthritis

Objectives

Autophagy is a homeostatic and physiological process that promotes the turnover of proteins and organelles damaged in conditions of cellular stress. We previously demonstrated that autophagy represents a key processing event creating a substrate for autoreactivity, which is involved in post-translational changes and generation of citrullinated peptides, recognized by the immune system in RA. In this study, we analysed whether autophagy is involved in other post-translational changes that can generate autoantigens, focusing on carbamylation processes. Carbamylation is a nonenzymatic post-translational modification, in which homocitrulline is generated by the reaction of cyanate with the primary amine of lysine residues; carbamylated peptides may accumulate during inflammation conditions.

Methods

The role of autophagy in the generation of carbamylated proteins was evaluated in vitro in fibroblasts as well as in synoviocytes from RA patients, treated with 5 μM tunicamycin or 200 nM rapamycin; the correlation between autophagy and carbamylated proteins was analysed in mononuclear cells from 30 naïve early-active RA patients.

Results

Our results demonstrated that cells treated with tunicamycin or rapamycin showed a significant increase of carbamylated proteins. Immunoblotting and immunoprecipitation experiments identified vimentin as the main carbamylated protein. Furthermore, a correlation was found between autophagy and carbamylation levels in mononuclear cells of naïve RA patients.

Conclusion

These data indicate that autophagy is able to induce in vitro carbamylation processes, and in vivo appears to be related to an increase in carbamylation during RA. These observations introduce a new pathogenetic mechanism of disease, which could contribute to more accurate monitoring of patients.

In Vitro Conditioning Determines the Capacity of Dental Pulp Stem Cells to Function as Pericyte-Like Cells

Dental pulp has been revealed as an accessible and a rich source of mesenchymal stem cells (MSCs) and its biological potential is currently under intense investigation. MSCs from dental pulp stem cells (DPSCs) have been indicated as a heterogeneous population oriented not only in repairing dentine but also in maintaining vascular and nervous homeostasis of the teeth. We sought to verify the phenotype of cells isolated from dental pulp of young donors and to investigate in vitro their role as pericyte-like cells. Specifically, we evaluated how culture conditions can modulate expression of pericyte markers in DPSCs and their capacity to stabilize endothelial tubes in vitro. DPSCs cultured in standard conditions expressed MSC markers and demonstrated to contain a population expressing the pericyte marker NG2. These DPSCs were associated with low sprouting capacity in extra-cellular (EC) Matrix and limited ability in retaining tubes formed by endothelial cells in a coculture angiogenesis model. When cultured in endothelial growth medium (EGM)-2, DPSCs significantly upregulated NG2, and partially alpha-smooth muscle actin. The resulting population conserved the stem marker CD73, but was negative for calponin and endothelial markers. EGM-2-conditioned DPSCs showed a higher sprouting ability in EC Matrix and efficient association with human umbilical vein endothelial cells allowing the partial retention of endothelial tubes for several days. Among growth factors contained in EGM-2 we identified basic fibroblast growth factor (bFGF) as mainly responsible for NG2 upregulation and long-term stabilization of endothelial tubes. According to the in vitro analysis, DPSCs represent an effective source of pericytes and the appropriate culture conditions could result in a population with a promising ability to stabilize vessels and promote vascular maturation.

Evaluation of the Submicron Particles Distribution Between Mountain and Urban Site: Contribution of the Transportation for Defining Environmental and Human Health Issues

Transportation is one of the main causes of atmospheric pollution, especially in downtown big cities. Researchers usually point their attention to gaseous and/or particulate matter pollutants. This paper investigated the role of submicron particles, particularly the fraction ranging between 5–560 nm, in aerosol chemistry for identifying the contribution of autovehicular traffic and investigating the doses deposited in the human respiratory tract. Measurements carried out by two Fast Mobility Particle Sizer (FMPS, TSI) analyzers were simultaneously performed at two different sampling sites (an urban and a mountain site) during workdays and weekends in July. The total particle number (2–2.5 times higher in the urban site), the aerosol size distribution (different modes during the day), and the ultrafine/non-ultrafine particle ratios (ranging between 2–4 times between two sites) were investigated and discussed in relationship to the high autovehicular traffic in Rome and the almost null anthropogenic emissions at the mountain site, as well as the differing contributions of both to the “fresh nucleation” and to “aged aerosol”. Furthermore, the regional cumulative number doses deposited in the human respiratory tract were studied for both sites: The difference between the urban/mountain site was very high (up to 15 fold), confirming the pollutant role of transportation.

Isolation, Propagation, and Prion Protein Expression During Neuronal Differentiation of Human Dental Pulp Stem Cells

Bioethical issues related to the manipulation of embryonic stem cells have hindered advances in the field of medical research. For this reason, it is very important to obtain adult stem cells from different tissues such as adipose, umbilical cord, bone marrow and blood. Among the possible sources, dental pulp is particularly interesting because it is easy to obtain in respect of bioethical considerations. Indeed, human Dental Pulp Stem Cells (hDPSCs) are a type of adult stem cells able to differentiate in neuronal-like cells and can be obtained from the third molar of healthy patients (13-19 ages). In particular, the dental pulp was removed with an excavator, cut into small slices, treated with collagenase IV and cultured in a flask. To induce the neuronal differentiation, hDPSCs were stimulated with EGF/bFGF for 2 weeks. Previously, we have demonstrated that during the differentiation process the content of cellular prion Protein (PrP^C) in hDPSCs increased. The cytofluorimetric analysis showed an early expression of PrP^C that increased after neuronal differentiation process. Ablation of PrP^C by siRNA PrP prevented neuronal differentiation induced by EGF/bFGF. In this paper, we illustrate that as we enhanced the isolation, separation and in vitro cultivation methods of hDPSCs with several easy procedures, more efficient cell clones were obtained and large-scale expansion of the mesenchymal stem cells (MSCs) was observed. We also show how the hDPSCs, obtained with methods detailed in the protocol, are an excellent experimental model to study the neuronal differentiation process of MSCs and subsequent cellular and molecular processes.

Cellular and Molecular Mechanisms Mediated by recPrPC Involved in the Neuronal Differentiation Process of Mesenchymal Stem Cells

Human Dental Pulp Stem Cells (hDPSCs) represent a type of adult mesenchymal stem cells that have the ability to differentiate in vitro in several lineages such as odontoblasts, osteoblasts, chondrocytes, adipocytes and neurons. In the current work, we used hDPSCs as the experimental model to study the role of recombinant prion protein 23⁻231 (recPrPC) in the neuronal differentiation process, and in the signal pathway activation of ERK 1/2 and Akt. We demonstrated that recPrPC was able to activate an intracellular signal pathway mediated by extracellular-signal-regulated kinase 1 and 2 (ERK 1/2) and protein kinase B (Akt). Moreover, in order to understand whether endogenous prion protein (PrPC) was necessary to mediate the signaling induced by recPrPC, we silenced PrPC, demonstrating that the presence of endogenous PrPC was essential for ERK 1/2 and Akt phosphorylation. Since endogenous PrPC is a well-known lipid rafts component, we evaluated the role of these structures in the signal pathway induced by recPrPC. Our results suggest that lipid rafts integrity play a key role in recPrPC activity. In fact, lipid rafts inhibitors, such as fumonisin B1 and MβCD, significantly prevented ERK 1/2 and Akt phosphorylation induced by recPrPC. In addition, we investigated the capacity of recPrPC to induce hDPSCs neuronal differentiation process after long-term stimulation through the evaluation of typical neuronal markers expression such as B3-Tubulin, neurofilament-H (NFH) and growth associated protein 43 (GAP43). Accordingly, when we silenced endogenous PrPC, we observed the inhibition of neuronal differentiation induced by recPrPC. The combined data suggest that recPrPC plays a key role in the neuronal differentiation process and in the activation of specific intracellular signal pathways in hDPSCs.

Exposure to individual and multiple carcinogenic metals during paediatric age: an experience from an Italian urban scenario

BACKGROUND

Exposure to single and multiple carcinogenic metals and/or semimetals represents a major environmental risk factor for public health. In particular, children are more susceptible to environmental pollutants than adults, but specific studies are still limited. The aims of the present study were: 1) to trace the exposure and co-exposure profiles to eight known or suspected carcinogenic metals and semimetals (As, Be, Cd, Co, Cr, Ni, Pb, and Sb); and: 2) to evaluate the influence of some possible interfering/confounding factors on the exposure to these elements during childhood.

STUDY DESIGN

Cross-sectional study.

METHODS

We recruited 159 healthy Italian children attending a primary school of the urban area of Rome, Italy. Selected metals were determined by inductively coupled plasma mass spectrometry on urinary samples collected at the end of a "typical" day (one sample for each child), while information about possible confounding/interfering factors were collected via questionnaires.

RESULTS

The great part of the studied children resulted co-exposed to the monitored metals: 83.2%, 69.2%, 51.0% and 29.3% of the participants were concurrently exposed to at least two, three, four and five trace elements, respectively. Gender was the only one among the investigated variable that significantly influenced the co-exposure, with females resulting at lower risk (OR = 0.392; 95 IC = 0.156 - 0.989; p < 0.047).

CONCLUSIONS

Given the importance of protecting child's health and the risks related to the exposure to carcinogenic metals, especially when they occur simultaneously, other researches in this field are strongly recommended.

Dual PI3 K/mTOR inhibition reduces prostate cancer bone engraftment altering tumor-induced bone remodeling

Morbidity in advanced prostate cancer patients is largely associated with bone metastatic events. The development of novel therapeutic strategies is imperative in order to effectively treat this incurable stage of the malignancy. In this context, Akt signaling pathway represents a promising therapeutic target able to counteract biochemical recurrence and metastatic progression in prostate cancer. We explored the therapeutic potential of a novel dual PI3 K/mTOR inhibitor, X480, to inhibit tumor growth and bone colonization using different in vivo prostate cancer models including the subcutaneous injection of aggressive and bone metastatic (PC3) and non-bone metastatic (22rv1) cell lines and preclinical models known to generate bone lesions. We observed that X480 both inhibited the primary growth of subcutaneous tumors generated by PC3 and 22rv1 cells and reduced bone spreading of PCb2, a high osteotropic PC3 cell derivative. In metastatic bone, X480 inhibited significantly the growth and osteolytic activity of PC3 cells as observed by intratibial injection model. X480 also increased the bone disease-free survival compared to untreated animals. In vitro experiments demonstrated that X480 was effective in counteracting osteoclastogenesis whereas it stimulated osteoblast activity. Our report provides novel information on the potential activity of PI3 K/Akt inhibitors on the formation and progression of prostate cancer bone metastases and supports a biological rationale for the use of these inhibitors in castrate-resistant prostate cancer patients at high risk of developing clinically evident bone lesions.

Role of Prion protein-EGFR multimolecular complex during neuronal differentiation of human dental pulp-derived stem cells

Cellular prion protein (PrP^C) is expressed in a wide variety of stem cells in which regulates their self-renewal as well as differentiation potential. In this study we investigated the presence of PrP^C in human dental pulp-derived stem cells (hDPSCs) and its role in neuronal differentiation process. We show that hDPSCs expresses early PrP^C at low concentration and its expression increases after two weeks of treatment with EGF/bFGF. Then, we analyzed the association of PrP^C with gangliosides and EGF receptor (EGF-R) during neuronal differentiation process. PrP^C associates constitutively with GM2 in control hDPSCs and with GD3 only after neuronal differentiation. Otherwise, EGF-R associates weakly in control hDPSCs and more markedly after neuronal differentiation. To analyze the functional role of PrP^C in the signal pathway mediated by EGF/EGF-R, a siRNA PrP was applied to ablate PrP^C and its function. The treatment with siRNA PrP significantly prevented Akt and ERK1/2 phosphorylation induced by EGF. Moreover, siRNA PrP treatment significantly prevented neuronal-specific antigens expression induced by EGF/bFGF, indicating that cellular prion protein is essential for EGF/bFGF-induced hDPSCs differentiation. These results suggest that PrP^C interact with EGF-R within lipid rafts, playing a role in the multimolecular signaling complexes involved in hDPSCs neuronal differentiation.

Cancer mortality in Rieti province (Latium Region, Italy) for the years 2006-2010: evaluation of temporal and spatial trends and comparison with the other Latium provinces

BACKGROUND

The present research aims to obtain information on cancer deaths in the five Latium provinces in the years 2006-2010 and to highlight similarities and differences between them.

METHODS

The survey was carried through statistical elaboration of cancer mortality data for the years 2006-2010 obtained from the National Institute of Statistics.

RESULTS

The mortality due to oncological diseases in Rieti province showed a decreasing temporal trend for the years investigated. Among all the Latium provinces, Rieti presented the lowest standardized mortality rates. This phenomenon could be related to specific environmental conditions and low levels of air, water and soil pollution affecting the Rieti province.

CONCLUSION

The results of the present study show that the "healthy" environment of Rieti province could be considered as a benchmark for studies in oncological diseases.

Morphine Withdrawal Modifies Prion Protein Expression in Rat Hippocampus

The hippocampus is a vulnerable brain structure susceptible to damage during aging and chronic stress. Repeated exposure to opioids may alter the brain so that it functions normally when the drugs are present, thus, a prolonged withdrawal might lead to homeostatic changes headed for the restoration of the physiological state. Abuse of morphine may lead to Reacting Oxygen Species-induced neurodegeneration and apoptosis. It has been proposed that during morphine withdrawal, stress responses might be responsible, at least in part, for long-term changes of hippocampal plasticity. Since prion protein is involved in both, Reacting Oxygen Species mediated stress responses and synaptic plasticity, in this work we investigate the effect of opiate withdrawal in rats after morphine treatment. We hypothesize that stressful stimuli induced by opiate withdrawal, and the subsequent long-term homeostatic changes in hippocampal plasticity, might modulate the Prion protein expression. Our results indicate that abstinence from the opiate induced a time-dependent and region-specific modification in Prion protein content, indeed during morphine withdrawal a selective unbalance of hippocampal Prion Protein is observable. Moreover, Prion protein overexpression in hippocampal tissue seems to generate a dimeric structure of Prion protein and α-cleavage at the hydrophobic domain. Stress factors or toxic insults can induce cytosolic dimerization of Prion Protein through the hydrophobic domain, which in turn, it stimulates the α-cleavage and the production of neuroprotective Prion protein fragments. We speculate that this might be the mechanism by which stressful stimuli induced by opiate withdrawal and the subsequent long-term homeostatic changes in hippocampal plasticity, modulate the expression and the dynamics of Prion protein.

Role of mitochondrial raft-like microdomains in the regulation of cell apoptosis

Lipid rafts are envisaged as lateral assemblies of specific lipids and proteins that dissociate and associate rapidly and form functional clusters in cell membranes. These structural platforms are not confined to the plasma membrane; indeed lipid microdomains are similarly formed at subcellular organelles, which include endoplasmic reticulum, Golgi and mitochondria, named raft-like microdomains. In addition, some components of raft-like microdomains are present within ER-mitochondria associated membranes. This review is focused on the role of mitochondrial raft-like microdomains in the regulation of cell apoptosis, since these microdomains may represent preferential sites where key reactions take place, regulating mitochondria hyperpolarization, fission-associated changes, megapore formation and release of apoptogenic factors. These structural platforms appear to modulate cytoplasmic pathways switching cell fate towards cell survival or death. Main insights on this issue derive from some pathological conditions in which alterations of microdomains structure or function can lead to severe alterations of cell activity and life span. In the light of the role played by raft-like microdomains to integrate apoptotic signals and in regulating mitochondrial dynamics, it is conceivable that these membrane structures may play a role in the mitochondrial alterations observed in some of the most common human neurodegenerative diseases, such as Amyotrophic lateral sclerosis, Huntington's chorea and prion-related diseases. These findings introduce an additional task for identifying new molecular target(s) of pharmacological agents in these pathologies.

Epidemiological profile of cancer mortality in a province of central Italy for the years 2008 and 2009: preliminary analysis

BACKGROUND

The aim of the study was to perform a preliminary analysis of the mortality data for cancer as widely as possible, in order to obtain useful information for planning specific public health interventions. For this purpose, data on cancer mortality in the province of Rieti (Latium, central Italy) have been collected and analysed. To date, in the Rieti province a Cancer Registry record is not available.

METHODS

The study was conducted through statistical analysis of cancer mortality data related to the years 2008 and 2009, obtained from the National Institute of Statistics. Data were cumulative for the province of Rieti and specific for the five districts in which the province is divided.

RESULTS

The standardized mortality rates obtained for Rieti province resulted lower than those reported for the other provinces of the Latium region, for Italy and for the European Community, both for 2008 and 2009. In these years, the anatomical areas more affected in terms of mortality were "trachea, bronchus and lung", "colorectal" and "stomach", but gender differences were evidenced.

CONCLUSIONS

The present study, also considering the limitation of two years studied only, leads to some basic insights about the importance of updating mortality data to trace an epidemiological profile, to evaluate the presence of risk and protective factors, to program strategically health interventions, and to assess the effectiveness of these interventions.

Modulatory Effect of Gliadin Peptide 10-mer on Epithelial Intestinal CACO-2 Cell Inflammatory Response

Celiac Disease (CD) is a chronic inflammatory enteropathy, triggered in genetically susceptible individuals by dietary gluten. Gluten is able to elicit proliferation of specific T cells and secretion of inflammatory cytokines in the small intestine. In this study we investigated the possibility that p10-mer, a decapeptide from durum wheat (QQPQDAVQPF), which was previously shown to prevent the activation of celiac peripheral lymphocytes, may exert an inhibitory effect on peptic-tryptic digested gliadin (PT-Gly)-stimulated intestinal carcinoma CACO-2 cells. In these cells, incubated with PT-Gly or p31-43 α-gliadin derived peptide in the presence or in the absence of p10-mer, IRAK1 activation and NF-kB, ERK1/2 and p38 MAPK phosphorylation were measured by immunoblotting, Cyclooxigenase 2 (COX-2) activity by PGE-2 release assay, and production of cytokines in the cell supernatants by ELISA. Our results showed that pre-treatment of CACO-2 cells with p10-mer significantly inhibited IRAK1 activation and NF-kB, ERK1/2 and p38 MAPK phosphorylation, as well as COX-2 activity (i.e. PGE-2 release) and production of the IL-6 and IL-8 pro-inflammatory cytokines, induced by gliadin peptides. These findings demonstrate the inhibitory effect of the p10-mer peptide on inflammatory response in CACO-2 cells. The results of the present study show that this p10-mer peptide can modulate "in vitro" the inflammatory response induced by gliadin peptides, allowing to move towards new therapeutic strategies. Turning off the inflammatory response, may in fact represent a key target in the immunotherapy of celiac disease.

A new 4-phenyl-1,8-naphthyridine derivative affects carcinoma cell proliferation by impairing cell cycle progression and inducing apoptosis

In targeted cancer therapy the search for novel molecules led to the discovery of a plethora of small organic molecules inhibiting cancer cell proliferation. Among these, quinazoline and derivatives, such as quinolines and naphthyridines, have been considered as of particular interest. One of these, the naphthyridine derivative 4-phenyl-2,7-di(piperazin-1-yl)-1,8-naphthyridine, has been analyzed in detail in the present work. We found that this compound elicited a powerful anti-proliferative activity on carcinoma cells, with IC50 values comparable with paradigmatic microtubule-deranging drugs. The mechanisms underlying this effect were seemingly due to a framework of cellular alterations that include peculiar alterations of mitochondria, i.e. an increase of mitochondrial membrane potential (MMP), followed by the typical MMP loss leading to the release of apoptogenic factors, and cell death by apoptosis. Furthermore, the analysis of cell cycle revealed that a significant percentage of treated cells was in G2/M phase. This block was seemingly due to a target effect of the naphthyridine derivative on microtubular network dynamic instability, which impaired mitotic spindle formation, possibly leading to mitotic catastrophy. Since the dual effects of naphthyridine derivative on cell cycle and mitotic spindle were obtained at very low concentrations, i.e. micromolar concentrations, we hypothesize that this compound could represent a new promising tool in the control of cancer cell proliferation.

Dynamics of mitochondrial raft-like microdomains in cell life and death

On the basis of the biochemical nature of lipid rafts, composed by glycosphingolipids, cholesterol and signaling proteins, it has been suggested that they are part of the complex framework of subcellular intermixing activities that lead to CD95/Fas-triggered apoptosis. We demonstrated that, following CD95/Fas triggering, cellular prion protein (PrP^C), which represents a paradigmatic component of lipid rafts, was redistributed to mitochondrial raft-like microdomains via endoplasmic reticulum (ER)-mitochondria associated membranes (MAM) and microtubular network.

 

Raft-like microdomains appear to be involved in a series of intracellular functions, such as: (1) the membrane “scrambling” that participates in cell death execution pathways, (2) the remodeling of organelles, (3) the recruitment of proteins to the mitochondria; (4) the mitochondrial oxidative phosphorylation and ATP production.

In conclusion, we suggest that lipid raft components can exert their regulatory activity in apoptosis execution at three different levels: (1) in the DISC formation at the plasma membrane; (2) in the intracellular redistribution at cytoplasmic organelles, and, (3) in the structural and functional mitochondrial modifications associated with apoptosis execution.

Trafficking of PrPc to mitochondrial raft-like microdomains during cell apoptosis

The cellular form of prion protein (PrP (c)) is a highly conserved cell surface GPI-anchored glycoprotein that was identified in cholesterol-enriched, detergent-resistant microdomains, named "rafts." The association with these specialized portions of the cell plasma membrane is required for conversion of PrP (c) to the transmissible spongiform encephalopathy-associated protease-resistant isoform. Usually, PrP (c) is reported to be a plasma membrane protein, however several studies have revealed PrP (c) as an interacting protein mainly with the membrane/organelles, as well as with cytoskeleton network. Recent lines of evidence indicated its association with ER lipid raft-like microdomains for a correct folding of PrP (c), as well as for the export of the protein to the Golgi and proper glycosylation. During cell apoptosis, PrP (c) can undergo intracellular re-localization, via ER-mitochondria associated membranes (MAM) and microtubular network, to mitochondrial raft-like microdomains, where it induced the loss of mitochondrial membrane potential and citochrome c release, after a contained raise of calcium concentration. We suggest that PrP (c) may play a role in the multimolecular signaling complex associated with cell apoptosis Lipid rafts and their components may, thus, be investigated as pharmacological targets of interest, introducing a novel and innovative task in modern pharmacology, i.e., the development of glycosphingolipid targeted drugs.