Bisphosphonate-related osteonecrosis of the jaws and dental surgery procedures in children and young people with osteogenesis imperfecta: A systematic review.

BACKGROUND: Bisphosphonates (BPs) contrast the bone fragility and improve bone density in some metastatic cancers and bone diseases, such as Osteogenesis Imperfecta (OI). BPs use has been associated with osteonecrosis of the jaws (BRONJs) in adults needing for invasive dental procedures. AIM: To conduct a systematic review on BRONJ occurrence after dental surgery in paediatric population under BPs therapy for OI, so as to identify the pre-surgical protocols adopted. DESIGN: According to PRISMA guidelines, Pubmed, Web of Science (WoS) and Cochrane were investigated on September 2018, and re-checked on July 2019. Inclusion criteria were English-language papers on children/young adults (until 24 years old) reporting dental/oral surgery procedures. RESULTS: Totally, 60 articles were found. After title/abstract reviews and duplicates exclusion, 22 eligible titles underwent full-text evaluation. Finally, 10 studies were included. CONCLUSIONS: The lack of BRONJ occurrence in paediatric population suffering OI and treated with BPs, was confirmed, but the reasons are still debated, being the BPs therapies and the surgical strategies various and not standardized. Longitudinal studies should evaluate what happens to those former children once adult, to evaluate the delayed BRONJs onset associated with the occurrence of comorbidities during the adulthood.

Steroids and growth factors in oral squamous cell carcinoma: useful source of dental-derived stem cells to develop a steroidogenic model in new clinical strategies.

OBJECTIVE: Head and neck region is involved in a high percentage of malignant lesions, and oral squamous cell carcinoma (OSCC) is undoubtedly the most frequently found, accounting for over 90% of malignant tumors. Hormone receptor overexpression, like Estrogen Receptor (ER), Progesterone Receptor (PR) and Endothelial Growth Factor Receptor (EGFR), and signaling have been related to the pathogenesis of OSCC. For metastasis of OSCC, Cancer Stem Cells (CSCs) undergo epithelial to mesenchymal transition (EMT) under the influence of growth factors, cytokines, and regulation of cadherins from the tumor's microenvironment. In this context, the stem cells may become a potential therapeutic target for OSCC through modulation of cytokines and RAS pathway, which is involved in intracell signal transduction. The objective of this study was to suggest an experimental steroidogenic model for OSCC in translational research. PATIENTS AND METHODS: Dental-derived Stem Cells (D-dSCs) have been obtained from apical papilla tissue that surrounds the developing tooth of healthy donors and cultured in vitro. The cells have been exposed to different concentrations of Estradiol (E2 - 10 nM and 40 nM) in order to verify their response. The number of cells and cell viability has been evaluated up to 96 hours of treatment. RESULTS: The results showed that cell growth was increased under estradiol treatments compared with cells maintained without estradiol. Moreover, no significant difference in cell death levels was detected among treatments. CONCLUSIONS: This work underlines as D-dSCs could represent a useful steroidogenic model for the development of the target and gene therapies in OSCC.

Analysis of saliva samples in patients with Prader-Willi syndrome.

Patients affected by Prader-Willi Syndrome (PWS) usually show orofacial dysfunction, poor oral hygiene, severe tooth wear, generalized caries and thick sticky saliva. The aim of this study was to evaluate molecular/ionic changings in PWS patients compared to controls, as well as unstimulated salivary flow rate (SFR); 7 patients with a mean age of 20.0±5.45 years were enrolled in the study group (PWS group) and 5 patients with a mean age of 22.6±3.05 years, in the control group. Results showed a greater Na+ (p=0.003), Cl+ (p=0.004) and P (p=0.001) concentration in saliva of PWS group as well as a greater concentration of secretory IgA (p=0.003) with a reduction of SFR (p=0.004) compared to controls. A Spearman’s analysis (based on the SFR of both groups) revealed an inverse correlation with Na (rho=-0.747), Cl (rho=-0.723), P (rho=-0.637) and sIgA (rho=-0.707) concentration and SFR, when linear regression model was performed only P and SFR were interdependent (ß=-0.748; p=0.005).

Lichen planus: molecular pathway and clinical implications in oral disorders.

Stem cells play a role in many mucosal disorders characterised by abnormal proliferation and differentiation of keratinocytes, such as oral lichen planus (OLP). In OLP there were changes in stem cell markers as component of integrin complexes α6 and ß1 integrin increased along with increase of melanoma-associated chondroitin sulphate proteoglycan (MCSP) and decreased of notch1 (N1) and keratin 15 (K15). Stem cell marker expression may be altered by pathological signalling in these lesions. Cadherins are transmembrane receptors that provide cell-cell contact and communication function through calcium-dependent homophilic and heterophilic interactions. In actively diseased areas of OLP lesions, basal keratinocytes downregulate CD40 and were focally E-cadherin-negative, in contrast to non-diseased areas and normal oral mucosa. This loss of E-cadherin expression may contribute to epithelial basal cell destruction and T-cell migration into the epithelial compartment in OLP. In addition, Growth factor pathways as a role in OLP and has been analyzed in this review.

Epigenetic Changes Induced by Green Tea Catechins a re Associated with Prostate Cancer.

Prostate cancer is one of the most difficult cancers to treat especially when it becomes hormone resistant such as castrate resistant prostate cancer (CRPC) and subsequent metastatic CRPC. Apart from the genetic alterations in prostate cancer, epigenetic modifications also play an important role in the development and neoplastic progression of this disease. These include DNA methylation, histone modifications, and non-coding microRNAs. miRNAs are a novel class of small endogenous single-stranded non-coding RNAs of 19-25 nucleotides in length that typically silence gene expression. Considering the reversibility of epigenetic alterations in early carcinogenesis process, reversion (correction) of these modifications by green tea catechins could be a promising strategy for cancer chemoprevention and therapy. Recent evidence suggests that green tea catechins such as epigallocatechin gallate (EGCG) not only act as epigenetic modulators but can also modify miRNA expression and their target mRNAs, consistently contributing to the inhibition of prostate carcinogenesis. Various studies also indicate that several green tea polyphenols (GTPs) exert synergistic effects with other cancer chemotherapeutic agents. Therefore, the use of appropriate combinations of green tea catechins with the existing chemotherapeutics will lead to a reduction in side effects without decreasing the chemotherapeutic effects. This review will summarize the key results from recent studies detailing the effects of green tea catechins such as EGCG on epigenetic alterations and miRNA expression in prostate cancer.

Antagonistic effects of chloroquine on autophagy occurrence potentiate the anticancer effects of everolimus on renal cancer cells.

Renal cell carcinoma is an aggressive disease often asymptomatic and weakly chemo-radiosensitive. Currently, new biologic drugs are used among which everolimus, an mTOR inhibitor, that has been approved for second-line therapy. Since mTOR is involved in the control of autophagy, its antitumor capacity is often limited. In this view, chloroquine, a 4-alkylamino substituted quinoline family member, is an autophagy inhibitor that blocks the fusion of autophagosomes and lysosomes. In the present study, we evaluated the effects of everolimus alone or in combination with chloroquine on renal cancer cell viability and verified possible synergism. Our results demonstrate that renal cancer cells are differently sensitive to everolimus and chloroquine and the pharmacological combination everolimus/chloroquine was strongly synergistic inducing cell viability inhibition. In details, the pharmacological synergism occurs when chloroquine is administered before everolimus. In addition, we found a flow autophagic block and shift of death mechanisms to apoptosis. This event was associated with decrease of Beclin-1/Bcl(-)2 complex and parallel reduction of anti-apoptotic protein Bcl(-)2 in combined treatment. At last, we found that the enhancement of apoptosis induced by drug combination occurs through the intrinsic mitochondrial apoptotic pathway activation, while the extrinsic pathway is involved only partly following its activation by chloroquine. These results provide the basis for new therapeutic strategies for the treatment of renal cell carcinoma after appropriate clinical trial.

Apoptosis induced by interferon-alpha and antagonized by EGF is regulated by caspase-3-mediated cleavage of gelsolin in human epidermoid cancer cells.

We have previously reported that interferon-alpha (IFNalpha) induces apoptosis and EGF can antagonize this effect in human epidermoid cancer KB cells. Since apoptosis occurs together with cytoskeleton reorganization we have evaluated if IFNalpha and EGF could modulate cell remodeling in our experimental conditions. We have found that 48 h 1,000 IU/ml IFNalpha induced structural reorganization of stress fibers and membrane delocalization and partial capping of the actin severing protein gelsolin. The transfection of KB cells with both a wild type (WT) or a C-terminal truncated form of gelsolin caused overexpression of the protein and an increase of both the spontaneous and IFNalpha-induced apoptosis and cell cytoskeletal modifications. In fact, after 48 h of treatment IFNalpha induced 45% of apoptotic cell death in parental cells while an approximately 80% of cell population was apoptotic in transfected cells. These effects occurred together with an increase of the expression and consequent degradation of gelsolin. Again the addition of EGF to IFNalpha-treated transfected cells caused a recovery of the apoptosis. Notably, IFNalpha and EGF did not modify the expression of other molecules associated to cytoskeleton such as focal adhesion kinase and vinculin. In the same experimental conditions IFNalpha induced also gelsolin cleavage that occurred together with caspase-3 activation and release of cytochrome c. All these effects were antagonized by the exposure of IFNalpha-treated KB to 10 nM EGF for the last 12 h. Moreover, the specific inhibition of caspase-3 with 20 microM DEVD completely abrogated apoptosis and gelsolin cleavage induced by IFNalpha. In conclusion, our data are the first demonstration that IFNalpha can induce morphological cell changes that are peculiar of apoptosis onset through the caspase-3-mediated cleavage of gelsolin. Furthermore, we have demonstrated that EGF is able to antagonize these effects through the inhibition of caspase-3 activation.

HIV type 1 Tat protein is a survival factor for Kaposi's sarcoma and endothelial cells.

The HIV-1 Tat protein has been directly implicated in the pathogenesis of AIDS-related Kaposi's sarcoma (KS); however, its effects on KS spindle-shaped and endothelial cell apoptosis are largely unexplored. Since susceptibility to apoptosis is relevant for tumor development and response to therapy, we investigated the effects of Tat on KS and endothelial cell survival from apoptosis. The effect of Tat was evaluated in three KS cell lines (KS-imm, KS-C1, and KS-L3) exposed to the chemotherapy agent vincristine, currently used for the treatment of this tumor, and in human umbilical vein-derived endothelial cells (HUVECs) induced to undergo apoptosis by serum withdrawal. Apoptosis was assessed by enzymatic assays, microscopic examination of chromatin and cytoskeleton, evaluation of plasma membrane integrity and subdiploid DNA content, TUNEL assays, and measurement of caspase-3 activity. Tat, in a dose-dependent manner, protected the three KS cell lines and HUVECs from apoptosis induced by vincristine or serum starvation, respectively. This effect appeared to be independent of modulation of Fas, Bcl-2, or Bax expression. In contrast, Tat upregulated Bcl-X(L) expression and induced a relevant decrease in caspase-3 activity in vincristine-treated KS cells. Taken together, these results suggest that the HIV-1 Tat protein may factor KS development and progression by sustaining endothelial and transformed cell survival.

Role of platelet-activating factor in functional alterations induced by xenoreactive antibodies in porcine endothelial cells.

BACKGROUND: Platelet-activating factor (PAF) is a phospholipid mediator of inflammation which has been implicated in rejection. The interaction of anti-alpha-galactosyl natural antibodies (anti-alpha gal Abs) with endothelial cells is the initial step for the development of xenograft rejection. In our study, we stimulated porcine aortic endothelial cells (PAEC) with anti-alpha gal IgG to investigate the synthesis of PAF from PAEC and its biological consequences. METHODS AND RESULTS: PAF was extracted and chromatographically purified from cultured PAEC stimulated with baboon anti-alpha gal Abs. The Abs induced a dose-dependent synthesis of PAF peaking after 30 min of incubation, and decreasing thereafter. Concomitant cell shape change, motility, and cytoskeleton redistribution were observed. These events were prevented by addition of a panel of PAF-receptor antagonists. An SV40 T-large antigen-immortalized PAEC line was engineered to express PAF acetyl-hydrolase (PAF-AH) cDNA, the major PAF-inactivating enzyme. These transfected cells exposed to anti-alpha gal Abs showed reduced cell contraction and motility compared with empty vector-transfected cells. Moreover, in PAEC stimulated with anti-alpha gal Abs, the synthesis of PAF promoted the adhesion of a monocytic cell line as shown by the inhibitory effect of PAF-receptor antagonists and of PAF-AH expression. Finally, studies on cell monolayer demonstrated an enhanced permeability 48 hr after exposure to anti-alpha gal Abs, and this increase was prevented by PAF-inactivation and by PAF-receptor blockade. CONCLUSIONS: These results demonstrate that on stimulation with anti-alpha gal Abs, PAEC synthetize PAF which can contribute to several vascular events involved in xenograft rejection.

Increased blood levels of platelet-activating factor in insulin-dependent diabetic patients with microalbuminuria.

BACKGROUND: Platelet-activating factor (PAF), a phospholipid mediator of inflammation, may induce an enhanced size- and charge-dependent glomerular permeability in experimental animals. Studies on the role of PAF in enhanced glomerular permeability in the early phase of diabetic nephropathy are still lacking. METHODS: We evaluated the intravascular levels of PAF and its main catabolic enzyme, the PAF-specific plasma acetyl-hydrolase (PAF-AH), in basal conditions and after exercise, in normo- or micro-albuminuric insulin-dependent diabetic (IDD) patients and in normal subjects. RESULTS: The results obtained indicate that the concentration of PAF in whole blood was significantly enhanced in basal conditions, during and after exercise in all microalbuminuric IDD patients, but not in normoalbuminuric IDD or in control subjects. The increased concentration of PAF did not correlate with changes in the activity of PAF-AH, suggesting an enhanced production rather than a decreased catabolism of PAF. CONCLUSIONS: These results indicate an association between increased production of PAF and enhanced glomerular permeability in microalbuminuric IDD patients.

Effect of platelet-activating factor receptor expression on CHO cell motility.

Tumor cell migration may favor local mass expansion and metastasis dissemination. Several tumors were found to express the receptor for platelet-activating factor (PAF), a potent mediator of leukocyte chemotaxis and endothelial cell migration. However, its functional role on tumor cells is largely unexplored. In the present study, we evaluated the motogenic effect of PAF on Chinese hamster ovarian (CHO) cancer cells transfected with the human PAF-receptor cDNA (CHO PAF-R). By using time-lapse recording, we detected a rapid motogenic response to PAF stimulation on CHO PAF-R, whereas no effect was evident on vector-only transfected cells. Such an effect was observed on scattered cell motility, on cells seeded on a fibronectin- or collagen-coated surface, and on migration of confluent monolayer cells. Cell speed increased at 1 h and was maximal 6-8 h after PAF stimulation on CHO PAF-R. Concomitantly, PAF induced marked changes in cytoskeleton actin distribution with cell contraction, assembling of stress fibers, and polar foci of adhesion. In conclusion, the present study demonstrates that PAF is a potent inducer of tumor cell motility, thus suggesting a role for this mediator in tumor growth and dissemination.

Platelet-activating factor enhances vascular endothelial growth factor-induced endothelial cell motility and neoangiogenesis in a murine matrigel model.

We previously reported that platelet-activating factor (PAF) enhances the angiogenic activity of certain polypeptide mediators such as tumor necrosis factor and hepatocyte growth factor by promoting endothelial cell motility. The purpose of the present study was to evaluate whether the synthesis of PAF induced by vascular endothelial growth factor (VEGF) might affect endothelial cell motility, microvascular permeability, and angiogenesis. The neoangiogenesis and synthesis of PAF induced by VEGF were studied in vivo in a murine Matrigel model. Dermal permeability was studied in mice by injection of (125)I-albumin. The synthesis of PAF, cell motility, and the increased (125)I-albumin transfer across endothelial monolayers were studied in vitro by using cultures of human umbilical cord vein-derived endothelial cells (HUVECs). The results obtained demonstrate that the neoangiogenesis induced by VEGF in vivo was associated with a local synthesis of PAF and was inhibited by WEB2170 and CV3988, 2 chemically unrelated, specific PAF-receptor antagonists. In contrast, WEB2170 did not inhibit VEGF-enhanced dermal permeability, suggesting that the latter was independent of the synthesis of PAF. In vitro, it was found that VEGF induced the synthesis of PAF by HUVECs in a dose- and time-dependent manner. The cell motility induced by VEGF was inhibited by PAF-receptor antagonists. In contrast, VEGF-induced proliferation of HUVECs and albumin transfer through HUVEC monolayer were unaffected by PAF-receptor antagonists. These results suggest that the synthesis of PAF induced by VEGF enhances endothelial cell migration and contributes to the angiogenic effect of VEGF in the in vivo Matrigel model.

Motility induced by human immunodeficiency virus-1 Tat on Kaposi's sarcoma cells requires platelet-activating factor synthesis.

In the present study, we evaluated whether motility of Kaposi's sarcoma (KS) spindle cells induced by HIV-1 Tat protein is dependent on the synthesis of platelet-activating factor (PAF). The results obtained indicate that Tat induced a dose-dependent synthesis of PAF from KS cells at a concentration as low as 0.1 ng/ml. PAF production started rapidly after Tat stimulation, peaking at 30 minutes and declining thereafter. Tat-induced cell migration was also a rapid event starting at 30 minutes. The motility was abrogated by addition of a panel of chemically unrelated PAF receptor antagonists (WEB 2170, CV 3988, CV 6209, and BN 52021), suggesting that the synthesized PAF mediates the motogenic effect of Tat. This effect was also present on cells plated on a type-I collagen-, fibronectin-, or basement membrane extract-coated surface. Expression of PAF receptor-specific mRNA was detected in KS cells. In addition, examination of the cytoskeletal organization showed that Tat-mediated KS cell redistribution of actin filaments and shape change was also inhibited by a PAF receptor antagonist. Moreover, PAF receptor blockade prevented the up-regulation of beta1 integrin and the down-regulation of alphavbeta3 observed after stimulation of KS cells with Tat. In conclusion, the results of the present study indicate that Tat-induced PAF synthesis plays a critical role in triggering the events involved in motility of KS cells.

Activation of CD40 favors the growth and vascularization of Kaposi's sarcoma.

Although CD40 is expressed by several tumor lines and is up-regulated in tumor vascular endothelium, its role in tumor biology is still unclear. In the present study, we investigated the role of CD40 in the growth and vascularization of Kaposi's sarcoma (KS). In vitro, stimulation of CD40 induced migration of KS cells and inhibited vincristine-induced apoptosis. Similarly, the CD40 engagement on endothelial cells resulted in cell contraction, migration, and prevention of serum withdrawal-apoptosis. To understand the biological relevance of CD40 in vivo, KS cells were engineered to express and release a soluble form of CD40 (KS-sCD40) able to disrupt CD40-CD154 interaction. SCID mice s.c. injected with KS-sCD40 cells developed tumors that were significantly smaller than those induced by control cells (KS-neo). In addition, KS-sCD40 tumors showed several areas of necrosis, diffuse presence of apoptotic cells, and poor vascularization. In contrast, KS-neo tumors showed few or absent areas of necrosis and apoptosis and intense vascularization. Moreover, anti-CD40 Abs stimulated neo-angiogenesis in a murine model in which s.c. implantation of Matrigel was used as a vehicle for the delivery of mediators. These observations provide demonstration that CD40 supports tumor cell survival, growth, and neo-vascularization of KS.

2-aminoanthracene as an analytical tool with the acetylation reaction catalyzed by arylamine N-acetyltransferase.

The polynuclear aromatic amine, 2-aminoanthracene, was found to be acetylated with high efficiency in the presence of acetyl-CoA by pigeon liver arylamine N-acetyltransferase (EC 2.3.1.5). As a consequence of acetylation the fluorescence properties of the compound dramatically change and the reaction time course can be easily followed fluorometrically at the emission wavelength of 425 nm upon excitation at 360 nm. When 2-aminoanthracene is employed with pigeon arylamine N-acetyltransferase, as the ultimate acceptor of the acetyl group in coupled fluorometric assays, it is possible to measure enzymatic activities, such as pyruvate dehydrogenase or carnitine acetyltransferase, in continuous assays rapidly and with high sensitivity or to determine with as much sensitivity important metabolites such as acetylcarnitine or acetyl-CoA.

Expression of L-selectin ligands by transformed endothelial cells enhances T cell-mediated rejection.

Recent immunohistochemical studies have suggested that L-selectin ligands may be implicated in the infiltration of tumors and rejected transplants by lymphocytes. In the present study, polyoma-middle T Ag-transformed endothelial cells (H.end), which typically form in vivo immunogenic vascular tumors resembling Kaposi's sarcoma, were engineered to express L-selectin ligands by stable transfection with a cDNA encoding alpha(1,3/4)-fucosyltransferase (H.endft). The ability of these cells to form tumors in the s.c. tissues of normal and immunocompromised mice was then compared with that of H.end cells transfected with the hygromycin-resistance vector only (H. endhygro). H.endhygro cells rapidly formed local and metastatic tumors in normal syngeneic mice, leading to death within 2-3 mo postinjection. By contrast, tumors derived from H.endft cells displayed a slower rate of growth, an absence of metastasis, and marked lymphocyte infiltration. Animals bearing these tumors survived for a significantly longer duration than animals injected with H.endhygro cells. Alternatively, H.endft and H.endhygro cells formed tumors with comparable aggressiveness in immunocompromised mice, resulting in animal death within 3 wk of injection. H.endft but not H.endhygro cells supported L-selectin-dependent adhesion and cytolytic T cell activity in vitro. Taken together, our observations indicate that the in situ expression of fucosyltransferase may significantly influence the cellular immune response in endothelioma tumors. These results may be relevant in understanding the development of vascular opportunistic tumors such as Kaposi's sarcoma.

HIV-1 kills renal tubular epithelial cells in vitro by triggering an apoptotic pathway involving caspase activation and Fas upregulation.

HIV-infected patients suffer several renal syndromes, which can progress rapidly from renal insufficiency to end-stage renal disease. Histologically, HIV-induced nephropathy is characterized by prominent tubulopathy with apoptosis of tubular cells. Clinical and experimental evidence suggests that renal injury may be directly related to virus infection. Although HIV-1 is a polytropic and not solely lymphotropic pathogen, the susceptibility of renal cells to HIV-1 remains to be determined. This paper demonstrates in vitro the permissiveness of proximal tubular epithelial cells (PTEC) to HIV-1 and describes the effects of PTEC infection to explain the pathogenesis of tubular damage in vivo. The results indicate that PTEC express HIV-specific receptor and coreceptors and sustain virus replication. We observed that HIV-1 infection causes the death of tubular cells by triggering an apoptotic pathway involving caspase activation. Fas upregulation but not Fas ligand expression was found in the infected PTEC. However, after HIV-1 infection, tubular cells became susceptible to apoptosis induced through Fas stimulation. Caspase inhibition prevented the death of the infected PTEC in spite of persistent viral replication. These findings may explain the prominent histopathology of HIV-associated nephropathy and demonstrate that the apoptosis of nonlymphoid cells can be directly induced by HIV-1.