Microenvironment and tumor cells: two targets for new molecular therapies of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC), is one of the most frequent human cancer and is characterized by a high mortality rate. The aggressiveness appears strictly related to the liver pathological background on which cancer develops. Inflammation and the consequent fibro/cirrhosis, derived from chronic injuries of several origins (viral, toxic and metabolic) and observable in almost all oncological patients, represents the most powerful risk factor for HCC and, at the same time, an important obstacle to the efficacy of systemic therapy. Multiple microenvironmental cues, indeed, play a pivotal role in the pathogenesis, evolution and recurrence of HCC as well as in the resistance to standard therapies observed in most of patients. The identification of altered pathways in cancer cells and of microenvironmental changes, strictly connected in pathogenic feedback loop, may permit to plan new therapeutic approaches targeting tumor cells and their permissive microenvironment, simultaneousl

Relative dentifrice abrasivity on dentin and enamel

The abrasive characteristics of six (6) brands of toothpastes on Enamel and Dentin material were assessed. Human teeth were sliced to expose the dentin surface and then polished using 3 μm and 0.25 μm diamond paste. The outside surface of the tooth (after slicing) was used as is for the enamel surface testing. The surface smoothness was evaluated prior to testing using a surface profiler and averaging four (4) to five (5) readings across the surface for each sample. The tooth slices were then embedded into the acrylic plate surface by routing out an area with a dental drill and using polymethylmethacrylate (PMMA) to adhere the teeth to the plate. An acrylic abrasion machine was used to brush each sample for 3000 strokes with each of the toothpastes being tested. At least three (3) samples of each material were used for each paste. The same type of medium stiffness brush was used for each test. The surface smoothness was then re-assessed using the surface profiler again averaging four (4) to five (5) readings across the surface. The data was statistically analyzed and ranked by abrasiveness

Epigenetics as an Evolutionary Tool for Centromere Flexibility

Centromeres are the complex structures responsible for the proper segregation of chromosomes during cell division. Structural or functional alterations of the centromere cause aneuploidies and other chromosomal aberrations that can induce cell death with consequences on health and survival of the organism as a whole. Because of their essential function in the cell, centromeres have evolved high flexibility and mechanisms of tolerance to preserve their function following stress, whether it is originating from within or outside the cell. Here, we review the main epigenetic mechanisms of centromeres’ adaptability to preserve their functional stability, with particular reference to neocentromeres and holocentromeres. The centromere position can shift in response to altered chromosome structures, but how and why neocentromeres appear in a given chromosome region are still open questions. Models of neocentromere formation developed during the last few years will be hereby discussed. Moreover, we will discuss the evolutionary significance of diffuse centromeres (holocentromeres) in organisms such as nematodes. Despite the differences in DNA sequences, protein composition and centromere size, all of these diverse centromere structures promote efficient chromosome segregation, balancing genome stability and adaptability, and ensuring faithful genome inheritance at each cellular generation

La tutela del paesaggio culturale e degli archivi delle comunità come presupposto dell’educazione civica

The theme of the cultural landscape and the enhancement of local knowledge and excellence is part of the third line envisaged for the teaching of civic education (sustainable development and knowledge of the territory). By cultural “landscape” we mean that interaction, referred to by two UNESCO Conventions and the European Landscape Convention, between the environment in the physical sense, which includes natural "backgrounds" as well as animal and plant biodiversity, with the cultural narratives that communities have transmitted over time, mainly through the oral tradition. To be valued, this "traditional knowledge" (of lifestyles, symbolic systems, working techniques) requires a concerted effort to strengthen memory (at an individual, collective, local, or global level), a faculty that unfortunately today seems to be in decline even in the context of school.Il tema del paesaggio culturale e della valorizzazione dei saperi e delle eccellenze locali, rientra nella terza linea prevista per l'insegnamento di educazione civica (sviluppo sostenibile e conoscenza del territorio). Per "paesaggio" culturale si intende quella interazione, richiamata da due Convenzioni UNESCO e dalla Convenzione Europea sui Paesaggi, fra l'ambiente in senso fisico, comprensivo degli "sfondi" naturali quanto della biodiversità animale e vegetale, con le narrazioni culturali che le comunità si sono trasmesse nel corso del tempo, preferibilmente at-traverso la tradizione orale. Tali "conoscenze tradizionali" (stili di vita, sistemi simbolici, tecniche lavorative), per essere valorizzate, richiedono un forte potenziamento della Memoria (individuale, collettiva, locale, globale), facoltà che purtroppo oggi sembra essere in declino anche nella Scuola

La statua di Glauco. Riflessioni sulla natura umana durante la pandemia

The statue of Glauco that the sea and the storms have disfigured so as to make its appearance more like a ferocious beast than a god, is the famous image with which Jean Jacques Rousseau, in the Discourse on the origin of inequality, questions himself on Human Nature, in a reflection that will have its purpose both in the political project of the Contract and in the pedagogical project of the Emilio. The image serves in fact to reiterate that that deterioration, that ugliness, is only external and that the statue (the man) has remained in its depths beautiful and good, since in him the feeling of piety, of his own and of his remains unchanged. dignity and the vocation to freedom of others. If this were not the case, there would be no possibility for political democracy and democratic education. The growing social inequalities, the artificialization of feelings and relationships due to technology, as well as the spread, after the pandemic, of a sort of mass "claustrophilia", a love for the closed, for one's own, with the consequent rejection of everything that comes from "outside", which is different, foreign or new, seems instead to give credit to Hobbes's thesis, namely that Human Nature is violent and aggressive and that man is always a wolf for the other man. However, it will be the task of the arts, sciences and, above all, of education, to demonstrate that, under the debris left by the salt, Glauco has remained good and that he can rediscover his true essence, the beauty of his original substance

Dynamics and interactions of an oncogenic homeotic protein within human replicative complexes

The regulation of human DNA replication operates via the time-programmed activation and deactivation of approximately 30,000 replication origins distributed along the genome. A multi-protein replicative complex recognizes and assembles onto each origin; this determines the local unwinding of the origin DNA and the start of two oppositely moving replicative forks. The mechanism that governs the selection of a specific DNA sequence as human (and, more generally, metazoan) origin, in the course of G1 phase of the cell-cycle, is still poorly understood. The lack of DNA-sequence consensus among well-characterized replication origins, together with the little bindingspecificity displayed by the Origin Recognition Complex, suggest that origin selection might rather be determined by local chromatin structures and/or accessory targeting proteins. With regard to the latter possibility, it was interesting to find out that three homeotic proteins, namely HOXC13, HOXC10, and HOXA13 display a specific affinity for a DNA fragment corresponding to the sequence covered by the Replicative Complex of the human Lamin B2 replication origin. In the study conducted during this Ph.D. program, the possible role of homeotic proteins in origin function was explored by investigating the involvement of a selected homeotic protein, namely HOXC13, within the replicative complexes in living human cells. To this purpose, recent advances in biophysical microscopy technologies were exploited to study in vivo the localization, dynamics, and interactions of HOXC13 protein in the context of DNA replication regulation. The data reported in this thesis demonstrate that HOXC13 indeed participates in origin function. The protein is a stable component of early replicating chromatin, as it displays stable chromatin binding in correspondence to the nuclear areas where replication foci of early S phase are collected. This peculiar behavior is driven by the homeodomain and relies mainly on the conserved homeodomain arginine-5 anchoring to the DNA minor groove. Furthermore, HOXC13 displays unambiguous affinity for origin sequences and for selected replicative-complex proteins. The close proximity of HOXC13 to both Cdc6 and ORC2 proteins measured in living cells proves that the homeotic protein is involved in direct protein-protein interactions within the replicative-complex; not unexpectedly, such interactions are modulated in a cell-cycle dependent fashion that is consistent with origin function. These observations are not restricted to a single origin, but rather appear to have a general significance in the nuclear architecture of DNA replication; nor are they restricted to a single homeotic protein, as the HOXC13 exerts its function via highly conserved homeodomain residues. Hence, this dissertation argues that the homeoproteins functionally contribute in a general manner, dependent on their chromatin-binding properties, to the specification of origins, likely the early replicating ones. In this view, HOX proteins, probably in the context of a multi-protein homeotic effector, contribute to recruit and stabilize the replicative complexes onto early replicating origins, in presence of specific chromatin and topological configurations. Considering that HOXC13, involved in development and differentiation, is also an oncoprotein, the data presented in this thesis, besides offering an indication for the basis of origin selection, hint at the homeotic proteins as actors in the cross-talk between development and DNA replication regulation

An epistatic mini-circuitry between the transcription factors Snail and HNF4a controls liver stem cell and hepatocyte features exhorting opposite regulation on stemness-inhibiting microRNAs

Preservation of the epithelial state involves the stable repression of EMT program while maintenance of the stem compartment requires the inhibition of differentiation processes. A simple and direct molecular mini-circuitry between master elements of these biological processes, may provide the best device to keep balanced such complex phenomena. In this work, we show that in hepatic stem cell Snail, a transcriptional repressor of the hepatocyte differentiation master gene HNF4, directly represses the expression of the epithelial microRNAs-200c and -34a, which in turn target several stem cell genes. Notably, in differentiated hepatocytes HNF4, previously identified as a transcriptional repressor of Snail, induces the microRNAs-34a and -200a, b, c that, when silenced, causes epithelial dedifferentiation and reacquisition of stem traits. Altogether these data unveiled Snail, HNF4 and microRNAs -200a, b, c and -34a as epistatic elements controlling hepatic stem cell maintenance/differentiation

TGFβ impairs HNF1α functional activity in Epithelial-to-Mesenchymal Transition interfering with the recruitment of CBP/p300 acetyltransferases

The cytokine transforming growth factor β (TGFβ) plays a crucial role in the induction of both epithelial-to-mesenchymal transition (EMT) program and fibro-cirrhotic process in the liver, where it contributes also to organ inflammation following several chronic injuries. All these pathological situations greatly increase the risk of hepatocellular carcinoma (HCC) and contribute to tumor progression. In particular, late-stage HCCs are characterized by constitutive activation of TGFβ pathway and by an EMT molecular signature leading to the acquisition of invasive and metastatic properties. In these pathological conditions, the cytokine has been shown to induce the transcriptional downregulation of HNF1α, a master regulator of the epithelial/hepatocyte differentiation and of the EMT reverse process, the mesenchymal-to-epithelial transition (MET). Therefore, the restoration of HNF1α expression/activity has been proposed as targeted therapeutic strategy for liver fibro-cirrhosis and late-stage HCCs. In this study, TGFβ is found to trigger an early functional inactivation of HNF1α during EMT process that anticipates the effects of the transcriptional downregulation of its own gene. Mechanistically, the cytokine, while not affecting the HNF1α DNA-binding capacity, impaired its ability to recruit CBP/p300 acetyltransferases on target gene promoters and, consequently, its transactivating function. The loss of HNF1α capacity to bind to CBP/p300 and HNF1α functional inactivation have been found to correlate with a change of its posttranslational modification profile. Collectively, the results obtained in this work unveil a new level of HNF1α functional inactivation by TGFβ and contribute to shed light on the early events triggering EMT in hepatocytes. Moreover, these data suggest that the use of HNF1α as anti-EMT tool in a TGFβ-containing microenvironment may require the design of new therapeutic strategies overcoming the TGFβ-induced HNF1α inactivation