Preclinical studies of the combined effect of anti-MYCN PNA and Retinoic Acid as potential approach to treat Neuroblastoma

Neuroblastoma (NB) is the deadliest cancer in early childhood. Around 25% of patients pre- sent MYCN-amplification (MNA) which is linked to poor prognosis, metastasis, and therapy- resistance. While retinoic acid (RA) is beneficial only for some NB patients, the cause of its resistance is still unknown. Thus, there remains a need for new therapies to treat NB. I show that MYCN-specific inhibition by the antigene oligonucleotide BGA002 in combination with 13-cis RA (BGA002-RA) overcome resistance in MNA-NB cell lines, leading to potent MYCN mRNA expression and protein decrease. Moreover, BGA002-RA reactivated neuron differentiation or led to apoptosis in MNA-NB cell lines, and inhibited invasiveness capacity. Since NB and PI3K/mTOR pathway are strictly related MYCN down-regulation by BGA002 led to mTOR pathway inhibition in MNA-NB, that was strengthened by BGA002-RA. I further analyzed if MYCN silencing may induce autophagy reactivation, and indeed BGA002-RA caused a massive increase in lysosomes and macrovacuoles in MNA-NB cells. In addition, while MYCN is known to induce angiogenesis, BGA002-RA in vivo treatment elim- inated the tumor vascularization in a MNA-NB mice model, and significantly increased the survival. Overall, these results indicate that MYCN modulation mediates the therapeutic efficacy of RA and the development of RA resistance in MNA-NB. Furthermore, by targeting MYCN, we show a cancer-specific way of mTOR pathway inhibition only in MNA-NB, avoiding side effects of targeting mTOR in normal cells. These findings warrant clinical testing of BGA002-RA as a potential strategy to overcome RA resistance in MNA-NB.

A comprehensive experimental and numerical approach for assessing the hydro-mechanical behaviour of river embankments

In this doctoral dissertation, a comprehensive methodological approach for the assessment of river embankments safety conditions, based on the integrated use of laboratory testing, physical modelling and finite element (FE) numerical simulations, is proposed, with the aim of contributing to a better understanding of the effect of time-dependent hydraulic boundary conditions on the hydro-mechanical response of river embankments. The case study and materials selected for the present research project are representative for the riverbank systems of Alpine and Apennine tributaries of the main river Po (Northern Italy), which have recently experienced various sudden overall collapses. The outcomes of a centrifuge test carried out under the enhanced gravity field of 50-g, on a riverbank model, made of a compacted silty sand mixture, overlying a homogeneous clayey silt foundation layer and subjected to a simulated flood event, have been considered for the definition of a robust and realistic experimental benchmark. In order to reproduce the observed experimental behaviour, a first set of numerical simulations has been carried out by assuming, for both the embankments and the foundation unit, rigid soil porous media, under partially saturated conditions. Mechanical and hydraulic soil properties adopted in the numerical analyses have been carefully estimated based on standard saturated triaxial, oedometer and constant head permeability tests. Afterwards, advanced suction-controlled laboratory tests, have been carried out to investigate the effect of suction and confining stresses on the shear strength and compressibility characteristics of the filling material and a second set of numerical simulations has been run, taking into account the soil parameters updated based on the most recent tests. The final aim of the study is the quantitative estimation of the predictive capabilities of the calibrated numerical tools, by systematically comparing the results of the FE simulations to the experimental benchmark.

A corpus-assisted approach to apology-like expressions in Japanese computer-mediated discourse

This thesis provides a corpus-assisted pragmatic investigation of three Japanese expressions commonly signalled as apologetic, namely gomen, su(m)imasen and mōshiwake arimasen, which can be roughly translated in English with ‘(I’m) sorry’. The analysis is based on a web corpus of 306,670 tokens collected from the Q&A website Yahoo! Chiebukuro, which is examined combining quantitative (statistical) and qualitative (traditional close reading) methods. By adopting a form-to-function approach, the aim of the study is to shed light on three main topics of interest: the pragmatic functions of apology-like expressions, the discursive strategies they co-occur with, and the behaviours that warrant them. The overall findings reveal that apology-like expressions are multifunctional devices whose meanings extend well beyond ‘apology’ alone. These meanings are affected by a number of discursive strategies that can either increase or decrease the perceived (im)politeness level of the speech act to serve interactants’ face needs and communicative goals. The study also identifies a variety of behaviours that people frame as violations, not necessarily because they are actually face-threatening to the receiver, but because doing so is functional to the projection of the apologiser as a moral persona. An additional finding that emerged from the analysis is the pervasiveness of reflexive usages of apology-like expressions, which are often employed metadiscursively to convey, negotiate and challenge opinions on how language should be used. To conclude, the study provides a unique insight into the use of three expressions whose pragmatic meanings are more varied than anticipated. The findings reflect the use of (im)politeness in an online and non-Western context and, hopefully, represent a step towards a more inclusive notion of ‘apologies’ and related speech acts.