Histone acetyltransferase inhibitor CPTH6 preferentially targets lung cancer stem-like cells

Cancer stem cells (CSCs) play an important role in tumor initiation, progression, therapeutic failure and tumor relapse. In this study, we evaluated the efficacy of the thiazole derivative 3-methylcyclopentylidene-[4-(4′-chlorophenyl)thiazol-2-yl]hydrazone (CPTH6), a novel pCAF and Gcn5 histone acetyltransferase inhibitor, as a small molecule that preferentially targets lung cancer stem-like cells (LCSCs) derived from non-small cell lung cancer (NSCLC) patients. Notably, although CPTH6 inhibits the growth of both LCSC and NSCLC cell lines, LCSCs exhibit greater growth inhibition than established NSCLC cells. Growth inhibitory effect of CPTH6 in LCSC lines is primarily due to apoptosis induction. Of note, differentiated progeny of LCSC lines is more resistant to CPTH6 in terms of loss of cell viability and reduction of protein acetylation, when compared to their undifferentiated counterparts. Interestingly, in LCSC lines CPTH6 treatment is also associated with a reduction of stemness markers. By using different HAT inhibitors we provide clear evidence that inhibition of HAT confers a strong preferential inhibitory effect on cell viability of undifferentiated LCSC lines when compared to their differentiated progeny. In vivo, CPTH6 is able to inhibit the growth of LCSC-derived xenografts and to reduce cancer stem cell content in treated tumors, as evidenced by marked reduction of tumor-initiating capacity in limiting dilution assays. Strikingly, the ability of CPTH6 to inhibit tubulin acetylation is also confirmed in vivo. Overall, our studies propose histone acetyltransferase inhibition as an attractive target for cancer therapy of NSCLC.

Neem oil nanoemulsions: characterisation and antioxidant activity

The aim of the present work is to develop nanoemulsions (NEs), nanosized emulsions, manufactured for improving the delivery of active pharmaceutical ingredients. In particular, nanoemulsions composed of Neem seed oil, contain rich bioactive components, and Tween 20 as nonionic surfactant were prepared. A mean droplet size ranging from 10 to 100 nm was obtained by modulating the oil/surfactant ratio. Physicochemical characterisation was carried out evaluating size, ζ-potential, microviscosity, polarity and turbidity of the external shell and morphology, along with stability in simulated cerebrospinal fluid (CSF), activity of Neem oil alone and in NEs, HEp-2 cell interaction and cytotoxicity studies. This study confirms the formation of NEs by Tween 20 and Neem oil at different weight ratios with small and homogenous dimensions. The antioxidant activity of Neem oil alone and in NEs was comparable, whereas its cytotoxicity was strongly reduced when loaded in NEs after interaction with HEp-2 cells.

Synthesis, biological evaluation and quantitative structure-active relationships of 1,3-thiazolidin-4-one derivatives. A promising chemical scaffold endowed with high antifungal potency and low cytotoxicity

With reference to recent studies reporting on the various biological properties of the thiazolidinone scaffold, we synthesized more than a hundred compounds characterized by a 1,3-thiazolidin-4-one nucleus derivatised at the C2 with a hydrazine bridge linked to (cyclo)aliphatic or hetero(aryl) moieties, and their N-benzylated derivatives. These molecules were assayed as potential anti-Candida agents and they were shown to possess comparable, and in some cases higher biological activity than well-established topical and systemic antimycotic drugs (i.e. clotrimazole, fluconazole, ketoconazole, miconazole, tioconazole, amphotericin B). Compounds endowed with the lowest MICs underwent further testing in order to assess their cytotoxic effect (CC₅₀) on Hep2 cells, which demonstrated their relative safety. Finally, QSAR and 3-D QSAR models were used to predict putative chemical modifications of the 1,3-thiazolidin-4-one scaffold in order to design new and potential more active compounds against Candida spp.

Synthesis and biological evaluation of anti-Toxoplasma gondii activity of a novel scaffold of thiazolidinone derivatives

We designed and synthesised novel N-substituted 1,3-thiazolidin-4-one derivatives for the evaluation of their anti-Toxoplasma gondii efficacy. This scaffold was functionalised both at the N1-hydrazine portion with three structurally different moieties and at the lactam nitrogen with substituted benzyl groups selected on the basis of our previous structure-activity relationships studies. Using three different assay methods, the compounds were assessed in vitro to determine both the levels of efficacy against the tachyzoites of T. gondii (IC₅₀ = 5-148 μM), as well as any evidence of cytotoxicity towards human host cells (TD₅₀ = 68 to ≥320 μM). Results revealed that ferrocene-based thiazolidinones can possess potent anti-tachyzoite activity (TI =2-64).

Bioactive isoflavones from Pueraria lobata root and starch: Different extraction techniques and carbonic anhydrase inhibition

Kudzu, the dried root of an important edible plant (Pueraria lobata), is used in Traditional Chinese Medicine for the important nutritional value strictly related to its isoflavone derivatives. These compounds characterize the quality of kudzu contained in different preparations, as pharmaceutical ingredient as well as dietary/food supplement (e.g. starch). The optimization of the isoflavones recovery, monitored by HPLC-PDA, through different innovative and conventional extraction techniques, e.g. microwave-assisted, ultrasound-assisted and conventional extraction, represented a suitable challenge in food industry and natural products evaluation. The impact on the isoflavone extraction by using an ionic liquid-assisted procedure was also considered. Furthermore, the inhibitory activity of the most representative isoflavones, isolated from kudzu, was evaluated using four isoforms (I, II, IX and XII) of human carbonic anhydrase (hCA) due to their role in several physiopathological processes.

Protective Effects Induced by Microwave-Assisted Aqueous Harpagophytum Extract on Rat Cortex Synaptosomes Challenged with Amyloid β-Peptide

Harpagophytum procumbens is a plant species that displays anti-inflammatory properties in multiple tissues. The iridoid glycosides arpagoside, harpagide, and procumbide appear to be the most therapeutically important constituents. In addition, harpagoside treatment exerted neuroprotective effects both in vitro and in vivo. Considering these findings, the aim of the present work is to explore the possible protective role of the previously described microwave-assisted aqueous extract of H. procumbens on rat hypothalamic (Hypo-E22) cells, and in rat cortex challenged with amyloid β-peptide (1-40). In this context, we assayed the protective effects induced by H. procumbens by measuring the levels of malondialdehyde, 3-hydroxykynurenine (3-HK), brain-derived neurotrophic factor, and tumor necrosis factor-α, 3-HK. Finally, we evaluated the effects of H. procumbens treatment on cortex levels of dopamine, norepinephrine, and serotonin. H. procumbens extract was well tolerated by Hypo-E22 cells and upregulated brain-derived neurotrophic factor gene expression but down-regulated tumor necrosis factor-α gene expression. In addition, the extract reduced amyloid β-peptide stimulation of malondialdehyde and 3-HK and blunted the decrease of dopamine, norepinephrine, and serotonin, in the cortex. In this context, our work supports further studies for the evaluation and confirmation of Harpagophytum in the management of the clinical symptoms related to Alzheimer's disease. Copyright © 2017 John Wiley & Sons, Ltd.

Optimization of Aqueous Extraction and Biological Activity of Harpagophytum procumbens Root on Ex Vivo Rat Colon Inflammatory Model

Harpagophytum procumbens has a long story of use for the treatment of inflammatory diseases. Considering both the antiinflammatory effects of H. procumbens in multiple tissues and the stability of harpagoside in artificial intestinal fluid, the aim of the present study was to explore the possible protective role of a microwave-assisted aqueous Harpagophytum extract (1-1000 μg/mL) on mouse myoblast C2C12 and human colorectal adenocarcinoma HCT116 cell lines, and isolated rat colon specimens challenged with lipopolysaccharide (LPS), a validated ex vivo model of acute ulcerative colitis. In this context, we evaluated the effects on C2C12 and HCT116 viability, and on LPS-induced production of serotonin (5-HT), tumor necrosis factor (TNF)-α, prostaglandin (PG)E₂ and 8-iso-prostaglandin (8-iso-PG)F_2α . Harpagophytum extract was well tolerated by C2C12 cells, while reduced HCT116 colon cancer cell viability. On the other hand, Harpagophytum extract reduced H₂ O₂ -induced (1 mM) reactive oxygen species (ROS) production, in both cell lines, and inhibited LPS-induced colon production of PGE₂ , 8-iso-PGF_2α , 5-HT and TNFα. Concluding, we demonstrated the efficacy of a microwave-assisted Harpagophytum aqueous extract in modulating the inflammatory, oxidative stress and immune response in an experimental model of inflammatory bowel diseases (IBD), thus suggesting a rational use of Harpagophytum in the management and prevention of ulcerative colitis in humans. Copyright © 2017 John Wiley & Sons, Ltd.

Open saccharin-based secondary sulfonamides as potent and selective inhibitors of cancer-related carbonic anhydrase IX and XII isoforms

A large number of novel secondary sulfonamides based on the open saccharin scaffold were synthesized and evaluated as selective inhibitors of four different isoforms of human carbonic anhydrase (hCA I, II, IX and XII, EC 4.2.1.1). They were obtained by reductive ring opening of the newly synthesized N-alkylated saccharin derivatives and were shown to be inactive against the two cytosolic off-target hCA I and II (K_is > 10 µM). Interestingly, these compounds inhibited hCA IX in the low nanomolar range with K_is ranging between 20 and 298 nM and were extremely potent inhibitors of hCA XII isoenzyme (K_is ranging between 4.3 and 432 nM). Since hCA IX and XII are the cancer-related isoforms recently validated as drug targets, these results represent an important goal in the development of new anticancer candidates. Finally, a computational approach has been performed to better correlate the biological data to the binding mode of these inhibitors.

Elucidation of the mechanisms governing the thermal diastereomerization of bioactive chiral 1,3,4-thiadiazoline spiro-cyclohexyl derivatives towards their anancomeric stereoisomers

Synthesis of bioactive 1,3,4-thiadiazoline-spiro-cyclohexyl-alkyl-substituted diastereomers by effective switching between kinetic and thermodynamic control.

Synthesis and pharmacological screening of a large library of 1,3,4-thiadiazolines as innovative therapeutic tools for the treatment of prostate cancer and melanoma

Antimitotic agents are widely used in cancer chemotherapy but the numerous side effects and the onset of resistance limit their clinical efficacy. Therefore, with the purpose of discovering more selective and efficient anticancer agents to be administered alone or in combination with traditional drugs, we synthesized a large library of 1,3,4-thiadiazoline analogues, maintaining the pharmacophoric structure of an antiproliferative compound known as K858: this is a new inhibitor of kinesin Eg5, able to induce the mitotic arrest in colorectal cancer cells and in xenograft ovarian cancer cells. We screened 103 compounds to assess their antiproliferative activity on PC3 prostate cancer cell line. Two derivatives, compounds 32 (corresponding to K858) and 33, have shown to be the most effective against prostate tumor cells and also towards two melanoma cell lines (SK-MEL-5 and SK-MEL-28) at low micromolar concentrations, confirming the pharmacological activity of this scaffold and revealing the potential role of 1,3,4-thiadiazolines in the management of cancer.

Abstract 2324: The histone acetyltransferase inhibitor CPTH6 selectively targets lung cancer stem-like cells

Targeting epigenetic regulators is emerging as a promising strategy for cancer therapy. In this context, we recently identified the thiazole derivative 3-methylcyclopentylidene-[4-(4′-chlorophenyl)thiazol-2-yl]hydrazone (CPTH6) as a novel pCAF and GCN5 histone acetyltransferase inhibitor. CPTH6 exerts in vitro anti-tumoral effect in a panel of human tumor cell lines derived from different histotypes. In this study, we evaluated the efficacy of CPTH6 as a novel drug that targets Lung Cancer Stem-like Cells (LCSC) derived from non-small cell lung cancer (NSCLC) patients. We found that CPTH6 has a stronger growth-inhibitory effect in patient-derived LCSC than in established NSCLC lines. Unlike LCSC models, in which CPTH6 treatment induces cell cycle perturbation and apoptosis even at low doses, in established NSCLC lines CPTH6 triggers a cell cycle perturbation associated to DNA damage only at higher concentrations. Of note, differentiated progeny of LCSC lines are more resistant to CPTH6 cytoxicity when compared to their undifferentiated counterparts. Interestingly, CPTH6 treatment is also associated with reduced expression of the CD133 stemness marker in LCSC lines. Analysis of the CD133+ subpopulation in LCSC lines indicates that CD133+ cells not only undergo apoptosis following CPTH6 treatment but also shift toward a more differentiated phenotype. Furthermore, the growth inhibitory effect seems to be tightly related to baseline expression of acetylated alpha-tubulin, which was particularly prominent in sensitive LCSC lines. In vivo experiments confirmes the antitumor efficacy of CPTH6, particularly in LCSC-derived models, where a pronounced apoptosis induction and growth inhibitory effect is observed after CPTH6 treatment. Overall, our studies propose histone acetyltransferase inhibition as an attractive target for cancer therapy of NSCLC.

Citation Format: Marta Di Martile, Mariannna Desideri, Teresa De Luca, Chiara Gabellini, Adriana Eramo, Michele Milella, Daniela Secci, Simone Carradori, Simona Buglioni, Donatella Del Bufalo, Daniela Trisciuoglio. The histone acetyltransferase inhibitor CPTH6 selectively targets lung cancer stem-like cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2324. doi:10.1158/1538-7445.AM2015-2324

Out of the active site binding pocket for carbonic anhydrase inhibitors

2-Benzylsulfinylbenzoic acid binds to human carbonic anhydrase II in a mode completely different from any other class of carbonic anhydrase inhibitors investigated so far.