Starting from a yeast phenotypic screening performed on 21 compounds, we described the identification of two small molecules (9 and 18) able to significantly reduce the S. cerevisiae cell growth, thus miming the effect of GCN5 deletion mutant. Tested on a GCN5-dependent gene transcription assay, compounds 9 and 18 gave a high reduction of the reporter activity. In S. cerevisiae histone H3 terminal tails assay, the H3 acetylation levels were highly reduced by treatment with 0.6-1 mM 9, while 18 was effective only at 1.5 mM. In human leukemia U937 cell line, at 1 mM 9 and 18 showed effects on cell cycle (arrest in G1 phase, 9), apoptosis (9), and granulocytic differentiation (18). When tested on U937 cell nuclear extracts to evaluate their histone acetyltransferase (HAT) inhibitory action, both compounds were able to reduce the enzyme activity when used at 500 microM. Another quinoline, compound 22, was synthesized with the aim to improve the activity observed with 9 and 18. Tested in the HAT assay, 22 was able to reduce the HAT catalytic action at 50 and 25 microM, thereby being comparable to anacardic acid, curcumin, and MB-3 used as references. Finally, in U937 cells, compounds 9 and 18 used at 2.5 mM were able to reduce the extent of the acetylation levels of histone H3 (9) and alpha-tubulin (9 and 18). In the same assay, 22 at lower concentration (100 microM) showed the same hypoacetylating effects with both histone and non-histone substrates.

DNA is acquiring a primary role in material development, self-assembling by design into complex supramolecular aggregates, the building block of a new-materials world. Using DNA nanoconstructs to translate sophisticated theoretical intuitions into experimental realizations by closely matching idealized models of colloidal particles is a much less explored avenue. Here we experimentally show that an appropriate selection of competing interactions enciphered in multiple DNA sequences results into the successful design of a one-pot DNA hydrogel that melts both on heating and on cooling. The relaxation time, measured by light scattering, slows down dramatically in a limited window of temperatures. The phase diagram displays a peculiar re-entrant shape, the hallmark of the competition between different bonding patterns. Our study shows that it is possible to rationally design biocompatible bulk materials with unconventional phase diagrams and tuneable properties by encoding into DNA sequences both the particle shape and the physics of the collective response.