Role of thymidine kinase 1 phosphorylation on 3’-deoxy-3’-[18F]-fluorothymidine uptake by cancer cells: implication for Positron Emission Tomography

Uncontrolled cell proliferation is one of the hallmarks of cancer and its inhibition is desired in cancer therapy. The thymidine analogue 3’-deoxy-3’-[18F]-fluorothymidine ([18F]FLT) is used to image tumour proliferation by positron emission tomography (PET). To be retained in cells, [18F]FLT is phosphorylated by thymidine kinase 1 (TK1), the first enzyme in the salvage pathway for DNA synthesis, and for this reason the cellular incorporation of [18F]FLT is dependent on TK1 activity. Of the mechanisms regulating TK1 activity, TK1 transcription is well recognised while post-translational enzyme modifications are less well understood. TK1 protein phosphorylation was investigated in cancer cells, hypothesising that, throughout the cell cycle, but particularly during G2/M phase, TK1 is subjected to different types of phosphorylation, which are responsible for regulating its activity, and therefore potentially modulating [18F]FLT uptake. An acrylamide phos-tag™ gel method was validated to enable discrimination of phosphorylated TK1. Three different phosphorylated forms of TK1 were detected during progression of cells within the cell cycle, one of which was specifically produced upon G2/M arrest. There were significant changes in [18F]FLT uptake subsequent to cell cycle arrest by biological means and following treatment with anti-cancer drugs and pharmacological modulators. Changes in TK1 enzyme activity were detected as variations in [18F]FLT retention, with significantly reduced uptake upon serum starvation-induced G1 arrest, and marked decreased uptake during S-phase arrest and after nocodazole- or paclitaxel-induced G2/M arrest. Phosphorylation of serine-13 and serine-231 of TK1 were implicated in regulating [18F]FLT uptake. To assess whether or not [18F]FLT-PET highlighted changes in proliferation in vivo, HCT116 tumour-bearing mice were treated with paclitaxel. Although long term treatment resulted in tumour growth delay, in the model and at drug doses and early time points considered for imaging, no significant changes in tumour [18F]FLT retention were observed in treated animals compared to controls. This correlated with similarly unremarkable changes in Ki67 and TK1 expression in excised tumour samples. Investigation of whether or not alternative nucleoside analogue scaffolds were incorporated into the DNA and if they were providing greater sensitivity for detecting cell proliferation, compared to [18F]FLT, was carried out. Two new radiotracers ([18F]FTT and [18F]FOT) were developed and tested for a) phosphorylation by TK1, b) accumulation into cells and c) metabolism and biodistribution. Both radiotracers proved not to be useful, being minimally phosphorylated by TK1 and therefore not retained in cells, and showing catabolism in vivo. Finally, specific mitotic inhibitors were characterised in vitro to determine their effects on TK1 phosphorylation and proteins involved in [18F]FLT uptake, in order to verify if [18F]FLT is a suitable biomarker to highlight mitotic arrest with these modern drugs. The key novel finding to evolve from this thesis is that measurement of tumour proliferation by [18F]FLT-PET is modulated by TK1 phosphorylation. This changes the notion that [18F]FLT uptake simply reflects changes in S-phase arrest/DNA synthesis to one that represents broad sensitivity to proliferation including G2/M arrest. New radiotracers that are specifically incorporated into DNA and whose uptake is TK1-independent could provide additional selectivity for imaging DNA synthesis.Open Acces

Crossing the Border A Comparative Study of the Forest in the Poems of Gennadij Ajgi and in the Actions of Kollektivnye Dejstvija

In my article, I provide a comparative analysis of the forest in the production of the Russian poet Gennadij Ajgi (1934-2006) and in the performances of the artistic group Kollektivnye Dejstvija Коллективные Действия  (Collective Actions, 1976-89). Relying on the principles of environmental ethics, I stress the creative value of marginality, related to both the neutral space of the forest in Soviet ideologized society and the selected authors’ exclusion from the official culture. Besides, I focus on the deep transformation of the lyrical subject who, by crossing the forest border, establishes a creative dialogic exchange with nature

May Joint Commitment Stabilize Modus Vivendi?

This contribution intends to extend my previous attempt to defend modus vivendi as an alternative way to include people who do not share the essentials of a liberal society. The idea was to respond to a claim to realism: besides loyal citizens, whose doctrines overlap on the basics of a fair society, there are people whose loyalty towards institutions is not be wholehearted – since they do not concur to their public justification – but who may endorse them in a stable way. I consider now a further way to deal with inclusion, compliance and stability: besides division on fundamental commitments and disagreement about values, peaceful coexistence may find strength in an alternative way to conceive the attitude of cooperation as rooted in a joint commitment. My argument will be presented as follows: a) I recall my conclusions about my idea of stable modus vivendi; b) I try and improve the wished outcome of stability in spite of partial political loyalty by reinforcing this with the argument of joint commitment; c) I draw some interlocutory conclusions

Reasonable Values and the Value of Reasonableness. Reflections on John Rawls’ Political Liberalism

This paper aims to question the idea of reasonableness in Rawls’ account of political liberalism. My point is that reasonableness as the moral basis of the liberal society provides restrictions for differences – be they philosophical, moral, religious, cultural – to be included in the liberal society. Notwithstanding Rawls’ attempt to expand political boundaries and to include those people who do not share moral liberal justification to justice as fairness, reasonableness selects “values holders” and assigns to the so-called “reasonable” a place in the political debate. The others, the “unreasonable”, are expected to become reasonable; alternatively, they would be paid control or even coercion in all the circumstances in which they should represent a risk for political stability. I believe that Rawls gives an incomplete account of unreasonableness: there may well be persons who are not “reasonable” in Rawlsian terms but who do not necessarily represent a danger for the just society. By the fact that they do not endorse values as freedom and equality in which fair cooperation is grounded, we cannot infer that they will necessarily try to violate the terms around which cooperation is structured by imposing their values on others. I proceed as follows: a) I detail the Rawlsian political turn in defending justice as fairness; b) I focus on the idea of reasonableness as the core of political liberalism; c) I defend the thesis that political liberalism needs to revise the idea of unreasonableness if it aims to deal with pluralism as a social and political fact

Fuga dall’io nel bosco primordiale. Una prospettiva ecocritica sulla poesia russa della novaja volna

In the Soviet artistic context, the origins of Postmodernism are based on the development of an underground cultural scene. Despite the lack of awareness on ecocriticism, poetical works by the authors associated to the second underground period show a strong connection with the theme of nature. This essay focuses on the symbolic meaning that can be identified in descriptions of forests. The forest, which is a recurring image in the poems by some postmodern Russian writers, becomes the passage to an unknown place beyond reality, where men can escape from socially established individual identities. Besides, the syntactic and visual crumbling of the poems shows that the denial of all cultural stratifications is needed to reach a deep self-awareness. The poetical fragments are interrupted by silent white spaces with no hierarchical order. These reveal the failure of language as an instrument toestablish an ideologically characterized reality.In the Soviet artistic context, the origins of Postmodernism are based on the development of an underground cultural scene. Despite the lack of awareness on ecocriticism, poetical works by the authors associated to the second underground period show a strong connection with the theme of nature. This essay focuses on the symbolic meaning that can be identified in descriptions of forests. The forest, which is a recurring image in the poems by some postmodern Russian writers, becomes the passage to an unknown place beyond reality, where men can escape from socially established individual identities. Besides, the syntactic and visual crumbling of the poems shows that the denial of all cultural stratifications is needed to reach a deep self-awareness. The poetical fragments are interrupted by silent white spaces with no hierarchical order. These reveal the failure of language as an instrument toestablish an ideologically characterized reality

Alcune norme per un’anarchia della lingua: i manifesti d’improvvisazione del sottosuolo letterario russo

In this essay I will analyze some literary manifestos written within important artistic movements which developed in Russian literary underground context after the 1960s, as a reaction to the ideological absolutism pursued by the Soviet dictatorship. In particular, I will focus on the contrast, the fine boundary, and the connection between the strict form of the literary manifesto, made by a series of rules, and the experimental spontaneity and chaos enunciated by the manifestos themselves. &nbsp

A rare case of enteric and systemic Yersinia enterocolitica infection in a chronic, not iron-overloaded dialysis patient

We present herein a case of bacterial gastroenteritis due to Yersinia enterocolitica, occurred in a young woman undergoing haemodialysis with a previous history positive for prolonged (20 years) immunosuppressive therapy for glomerulonephritis before and for kidney transplant later. The patient's outcome was favourable after a third-generation cephalosporin treatment without complications. The possible pathophysiological association between patient clinical condition and Yersinia bacteraemia is discussed, along with the review of literature

Vulnerability, Responsibilities and Migration

Vulnerability is commonly considered as a feature of human beings on which our duties towards each other are grounded: we ought to help the vulnerable in virtue of their being such. Our duties seem rather clear when those in need are close to us, both physically and culturally, but less so when they are distant in either of the two senses. In this essay we wish to investigate the strength of our duties towards migrants, who are often either culturally or physically distant, yet vulnerable by definition – fleeing from wars, dictatorships, poverty, climate change, or other calamities. The view we aim to defend, is that our duties towards them, unlike what has been suggested by David Miller, are duties of justice, not of beneficence, and involve duties to host. This, we claim, is owed to migrants’ very vulnerability, which is not due to some kind of misfortune, but, eventually, to some form of injustice. We will also claim that taking into account migrants’ own responsibility, either as individuals or as members of a collectivity, is of no practical use when establishing our duties to host them