Stefania Butini

Acute myeloid leukemia (AML) is the most common form of acute leukemia. It is characterized by unfavorable prognosis, elevated rates of recurrence, short overall survival and high mortality rates. Genetic and epigenetic aberrations contribute to its initiation and progression, presenting a considerable clinical challenge. Genomic investigations revealed that FMS‐like tyrosine kinase 3 (FLT3), a receptor tyrosine kinase regulating the proliferation and differentiation of hematopoietic cells, is overexpressed in AML leukemic blasts. To date, FDA has approved only three FLT3 inhibitors for targeted AML therapy (midostaurin, gilteritinib, quizartinib). These molecules feature several nitrogen atoms; in particular quizartinib contains an oxazole and a urea group that are involved in interactions with FLT3 kinase domain. Similarly, different N‐containing heterocycles have proven to play a key role in other FLT3 inhibitors. Though small‐molecule FLT3 inhibitors encompass various chemical classes, N‐containing heterocycles and particularly the azole core represent the most common scaffold. The electron‐rich properties of the azoles allow them to easily bind with enzymes and receptors. Based on this, we will provide a general overview of FLT3 inhibitor classes in AML, along with a comprehensive report on azole‐based structures, reviewing recent contributions to the field.

Chronic lymphocytic leukemia (CLL) is a hematological malignancy characterized by the accumulation of mature CD5⁺ B cells largely due to defective apoptosis. Prolonged leukemic cell survival has been linked to downregulation of the pro-apoptotic adaptor p66Shc and its transcription factor STAT4, both of which are typically reduced in CLL patients. To date, a clear mechanistic explanation for STAT4 deficiency in CLL has not yet been provided. Restoring STAT4 expression or activating its residual function may represent an attractive therapeutic strategy. Histone deacetylase 6 (HDAC6) directly deacetylates and suppresses STAT4 in T lymphocytes, suggesting that a similar mechanism may operate in CLL cells. In this study, we hypothesized that HDAC6-mediated STAT4 inhibition also occurs in CLL cells and contributes to leukemic cell survival. Accordingly, we tested the potent HDAC6 inhibitor Taginostat (HDAC6 IC₅₀ = 7.9 nM) and found that it enhanced p66Shc expression and restored apoptosis in CLL cells. These effects were reproduced by HDAC6 silencing. Flow cytometric and western blot analyses showed that Taginostat boosted residual STAT4 activity by enhancing its phosphorylation. Moreover, transient transfection with STAT4-luciferase or STAT4-green fluorescent protein (GFP) constructs demonstrated that Taginostat promoted both the nuclear translocation and transcriptional activity of STAT4. In addition, in vivo experiments conducted in the Eµ-TCL1 mouse model of CLL demonstrated that Taginostat treatment counteracted disease development, significantly reducing the leukemia burden. Collectively, these findings validate HDAC6 inhibition as a valuable therapeutic strategy for promoting STAT4 activation in CLL cells, restoring the apoptotic cascade, and counteracting disease progression.

Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen for which new antimicrobial strategies are urgently needed. To facilitate the establishment of the infection, P. aeruginosa produces a remarkable assortment of both cell-associated and extracellular virulence factors. The expression of numerous virulence traits is regulated by the pqs quorum sensing (QS) system, which relies on multiple enzymes for the biosynthesis of 2-alkyl-4-quinolone (AQ) signal molecules and on the transcriptional regulator PqsR, whose activity is triggered by AQ binding. Herein, we report on the design and synthesis of novel quinazolinone-based PqsR modulators, which led to the identification of two novel compounds endowed with anti-PqsR activity in the submicromolar range. Additionally, these derivatives inhibited the production of PqsR-controlled virulence factors in laboratory strains and clinical isolates of P. aeruginosa.

The escalating threat of antimicrobial resistance (AMR) compels the development of novel antibiotics with broad spectrum activity and environmentally responsible degradation profiles. Chalcones, naturally occurring 1,3-diaryl-2-propen-1-ones, have emerged as promising scaffolds due to their pleiotropic bioactivity and structural tunability. In this study, we explored the synthesis and functionalization of oxyprenylated chalcones as potential antibacterial compounds and explored their functionalization with protonatable moieties to enhance their affinity for bacterial membranes and their solubility properties. Starting from hydroxycordoin 1a, we synthesized a series of isomeric and hydroxy derivatives, with the aim of studying their structure-activity relationships, and based on the initial results we further modified their structure by including protonatable side chains. A key synthetic step was optimized using a Design of Experiments (DoE) approach, promoting resource efficiency in line with Green Chemistry principles. The antibacterial properties of the synthesized compounds were evaluated in vitro against Gram-positive and Gram-negative strains, and their toxicological profiles and predicted environmental biodegradability were also assessed. These multifunctional chalcone derivatives demonstrate potential as effective and sustainable antimicrobial agents and the benzofuran derivative 20, the most potent compound of the series, could represent an interesting compound for further optmization

Class I histone deacetylases (HDACs) are frequently overexpressed in colorectal cancer (CRC). Combining computational, synthetic, and biological efforts, we developed novel o-aminobenzamide-based HDAC inhibitors (HDACis) optimized for class I enzyme-specific targeting. Compounds 5d and 5i emerged as lead candidates, showing strong antiproliferative effects in CRC cells with low toxicity in healthy colon epithelium. Both compounds disrupted the G2/M checkpoint through distinct mechanisms. 5i, although less potent (HDAC1 IC₅₀ = 1508 nM), retained selectivity, upregulated p21, and triggered pronounced apoptosis. 5d (Colrestat), one of the most selective class I HDACis to date (HDAC1 IC₅₀ = 41.2 nM, HDAC2 IC₅₀ = 52.5 nM, and HDAC3 IC₅₀ = 74.3 nM), induced H3K9 acetylation, p21 upregulation, and G2/M arrest. The short-term in vitro effects of 5d were modulated by a compensatory upregulation of autophagy. However, in long-term, this protective mechanism becomes insufficient to sustain tumor survival, resulting in strong antitumor efficacy in vivo in the CAM assay for both compounds even outperforming entinostat.

Walnuts (Juglans regia L.) are recognized for their rich nutritional profile and health-promoting properties. This study investigates the impact of biostimulation, via wood distillate application, on the chemical composition and therapeutic potential of walnut kernels, focusing on their wound healing activity. Biostimulated walnuts showed enhanced levels of phenolic compounds including antioxidants, sugars, and amino acids compared to untreated or agrochemically treated controls. Phytocomplexes extracted from walnut kernels using green methodologies were tested on human keratinocytes (HaCaT), revealing pro-migratory effect, boosted by biostimulation. Molecular analyses demonstrated the activation of epithelial–mesenchymal transition (EMT) pathways, marked by downregulation of epithelial markers and upregulation of mesenchymal genes such as MMP3, MMP9, vimentin, and SMAD3. Furthermore, a synergistic effect was observed between extracts derived from biostimulated kernels and manuka honey in promoting wound closure. These findings suggest that kernels from biostimulated walnuts may serve as functional foods, paving the way for their use in regenerative medicine.

Among genetic retinal disorders, retinitis pigmentosa (RP) is characterized by degeneration of rod photoreceptors caused by a large number of diverse mutations, most of which act through different pathways to which epigenetic targets also contribute. The eraser enzymes lysine demethylase 1 (LSD1) and histone deacetylase 1 (HDAC1) play major roles in the development of rod photoreceptors, and their inhibitors were shown to block inherited rod degeneration, preserving vision and contributing to a general anti-inflammatory profile at the retinal level. In this work, we proposed the development of polypharmacological agents targeting class I HDAC/LSD1 enzymes with the aim of treating the rd10 mice model of RP. The new small library of compounds is typified by hybrid (±)-3d, which showed IC₅₀ values of 1702, 842, and 358 nM against HDAC1, HDAC2, and HDAC3, respectively, while inhibiting LSD1 with an IC₅₀ value of 1074 nM. When tested on hydrogen peroxide-stressed ARPE-19 and 661W retinal cells at a concentration of 10 μM, (±)-3d showed a promising antioxidant profile, increasing the cellular levels of acetylated and methylated histone H3, and was selected for further studies also in light of its calculated IH-L. In the rd10 mice RP model, a single intravitreal injection of (±)-3d, at the same concentration used in cells, enhanced photoreceptor survival, downregulated retinal expression of the inflammatory genes GFAP, Ccl2, and Ccl12, and effectively preserved the retinal pigment epithelium barrier. Furthermore, (±)-3d promoted the acetylation and methylation of histone H3, thus confirming the engagement of both class I HDAC and LSD1.