Spectroscopic and in silico studies on the interaction of substituted-pyrazolo[1,2-a]benzo[1,2,3,4]tetrazine-3-one derivatives with c-myc and Tel22

As extension of previous results reached on the pyrazolo[1,2-a]benzo[1,2,3,4]tetrazin-3-one derivatives (PBTs) endowed with anticancer potential, we focused our research interest to new emerging and challenging biological targets involved in carcinogenic process. More precisely to gene promoter related to the oncoprotein c-myc as well as Tel22. C-mycis overexpressed in a large number of cancer and related binders are potential anticancer drugs because they target a promoter quadruplex present upstream of the proto-oncogene myc,down-regulating its expression. Indeed, one of the possible mechanisms underlying the antiproliferative activity of anticancer drugs is precisely based on the induction of quadruplex structure in c-myc, with consequent blockage of oncogene expression. Analogously, telomeric DNA binders inhibit the ability, found in most human cancer cells,to indefinitely replicate becoming immortal, as they prevent the hybridization of the telomerase RNA template onto the primer. Therefore, the discovery of new molecular entity able to tune the binding or the stabilization of the G4 quadruplex represents a current therapeutically approach for anticancer diseases [1]. A preliminary NCI screening on variously substituted pyrazolo[1,2-a]benzo[1,2,3,4]tetrazin-3-one derivatives (PBTs) against a panel of 60 tumor cell lines, evidenced a promising anti-proliferative activity in the ?M and sub-?M range. Depending on the position and nature of the substituents, several derivatives targeted selectively specific tumor cells or in other cases more than ones. These attractive results, for this tricycle scaffold, biologically unexplored so far, prompted us to move to new optimized structures followed by evaluation on apoptosis induction and cell cycle perturbation [2]. Once assessed their anticancer potential, on PBTs further deeper studies became necessary, in order to get insights on their mechanism of action. Thus, more specific biological targets, such as duplex DNA and topoisomerase(II) catalytic cycle, were approached, including in silico support [3]. Here, extending the research on other recently recognized anticancer targets, we planned to evaluate the effects of PBTs on c-myc and Tel22 by mean of circular dichroism (CD) and related melting experiments. In support, molecular dynamics (MD) and docking techniques permitted us to gain additional insights on the observed effects. The outcomes will be shown with more details at poster session. [1] [Stephen Neidle, Nature Reviews Chemistry1, 2017, 0041]. [2] F. Mingoia, C. Di Sano, F. Di Blasi, M. Fazzari, A. Martorana, A.M. Almerico, A. Lauria Eur. J. Med. Chem. 2013, 64, 345-356. [3] A. Lauria, F. Mingoia, A. Garcia-Arcaez, A. Martorana, L. Dalla Via, Chem. Biol. DrugDes. 2018, 91, 463-477