ß-Carboline derivatives are potent against Acute Myeloid Leukemia in vitro and in vivo.

BACKGROUND: ß-carboline alkaloids exert a distinguished ability to impair cell growth and induce cell death in a variety of cancers and the evaluation of such new therapeutic candidates may denote new possibilities for leukemia treatment. In this present study, we screened 12 ß-carboline derivatives containing different substituents at 1- and 3-positions of ß-carboline nucleus for their antineoplastic activities in a panel of leukemia cell lines. METHODS: The cytotoxic effects of the ß-carboline derivatives were evaluated in different leukemia cell lines as well as reactive oxygen species (ROS) generation, autophagy, and important signaling pathways. RESULTS: Treatment with the ß-carboline derivatives resulted in a potent antineoplastic activity leading to a reduced cell viability that was associated with increased cell death in a concentration-dependent manner. Interestingly, the treatment of primary mononuclear cells isolated from the peripheral blood of healthy donors with the ß-carboline derivatives showed a minor change in cell survival. The antineoplastic activity occurs by blocking ROS production causing consequent interruption of the PI3K/AKT and MAPK/ERK signaling and modulating autophagy processes. Notably, in vivo, AML burden was diminished in peripheral blood and bone marrow of a xenograft mouse model. CONCLUSIONS: Our results indicated that ß-carboline derivatives have an on-target malignant cell-killing activity and may be promising candidates for treating leukemia cells by disrupting crucial events that promote leukemia expansion and chemotherapy resistance.

Sensitizing agents found in children and adolescents with recalcitrant atopic dermatitis: a cross-sectional study with a pediatric battery.

BACKGROUND: Atopic dermatitis is the most common inflammatory skin disease in childhood and has an important impact on quality of life, especially severe cases or those that are recalcitrant to treatments. Sensitization to allergens with the potential for allergic contact dermatitis is a factor associated with cases of recalcitrant atopic dermatitis. Understanding the relationship between atopic dermatitis, allergens, and allergic contact dermatitis is essential. In Brazil, there are no studies on sensitization to allergens found in patch tests with pediatric batteries in patients with atopic dermatitis. OBJECTIVES: To verify the main sensitizing agents, the prevalence of allergic contact dermatitis and the epidemiological and clinical profile of children and adolescents with atopic dermatitis. METHODS: Cross-sectional, prospective study in patients between 4 and 18 years of age, with recalcitrant atopic dermatitis, treated at the Sanitary Dermatology Outpatient Clinic (RS). All patients underwent patch tests with a battery of pediatric allergens. RESULTS: The prevalence of sensitization and allergic contact dermatitis in the evaluated patients was 37.07% (20/54) and 27.7% (15/54), respectively. The most frequent allergens were: nickel sulfate (16.7%), disperse blue (5.6%), and fragrance mix I (5.6%). Nickel was associated with the female sex (p = 0.019). STUDY LIMITATIONS: Sample size and selection, absence of a control group. CONCLUSIONS: A proportion of patients with recalcitrant atopic dermatitis may be sensitized to different allergens and may even have developed allergic contact dermatitis. Recognizing this context is important in the prevention strategy and management of the disease.

ß-carbolines RCC and C5 induce the death of Leishmania amazonensis intracellular amastigotes.

Background: Cutaneous leishmaniasis is caused by Leishmania spp., and its treatment is limited. The ß-carbolines have shown activity against kinetoplastids. Aim: To evaluate the activity and effects of the ß-carbolines, N-{2-[(4,6-bis(isopropylamino)-1,3,5-triazin-2-yl)amino]ethyl}-1-(4-methoxyphenyl)-ß-carboline-3-carboxamide (RCC) and N-benzyl-1-(4-methoxy)phenyl-9H-beta-carboline-3-carboxamide (C5), against L. amazonensis intracellular amastigotes and to suggest their mechanism of action. Methods: We analyzed the activity and cytotoxicity of ß-carbolines and the morphological alterations by electron microscopy. Mitochondrial membrane potential, production nitric oxide, reactive oxygen species, lipidic bodies, autophagic vacuoles and ATP were also evaluated. Results & conclusion: The results showed that RCC and C5 are active against intracellular amastigotes and were able to induce oxidative stress and ultrastructural alterations such as accumulation of lipid bodies and autophagic vacuoles, leading to parasite death.

Sensitizing agents found in children and adolescents with recalcitrant atopic dermatitis: a cross-sectional study with a pediatric battery

Abstract Background Atopic dermatitis is the most common inflammatory skin disease in childhood and has an important impact on quality of life, especially severe cases or those that are recalcitrant to treatments. Sensitization to allergens with the potential for allergic contact dermatitis is a factor associated with cases of recalcitrant atopic dermatitis. Understanding the relationship between atopic dermatitis, allergens, and allergic contact dermatitis is essential. In Brazil, there are no studies on sensitization to allergens found in patch tests with pediatric batteries in patients with atopic dermatitis. Objectives To verify the main sensitizing agents, the prevalence of allergic contact dermatitis and the epidemiological and clinical profile of children and adolescents with atopic dermatitis. Methods Cross-sectional, prospective study in patients between 4 and 18 years of age, with recalcitrant atopic dermatitis, treated at the Sanitary Dermatology Outpatient Clinic (RS). All patients underwent patch tests with a battery of pediatric allergens. Results The prevalence of sensitization and allergic contact dermatitis in the evaluated patients was 37.07% (20/54) and 27.7% (15/54), respectively. The most frequent allergens were: nickel sulfate (16.7%), disperse blue (5.6%), and fragrance mix I (5.6%). Nickel was associated with the female sex (p = 0.019). Study limitations Sample size and selection, absence of a control group. Conclusions A proportion of patients with recalcitrant atopic dermatitis may be sensitized to different allergens and may even have developed allergic contact dermatitis. Recognizing this context is important in the prevention strategy and management of the disease.

Anticholinesterase activity of ß-carboline-1, 3, 5-triazine hybrids

Abstract The ß-carboline-1,3,5-triazine hydrochlorides 8-13 were evaluated in vitro against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The analysed compounds were selective to BuChE, with IC50 values in the range from 1.0-18.8 µM being obtained. The N-{2-[(4,6-dihydrazinyl-1,3,5-triazin-2-yl)amino]ethyl}-1-phenyl-ß-carboline-3-carboxamide (12) was the most potent compound and kinetic studies indicate that it acts as a competitive inhibitor of BuChE. Molecular docking studies show that 12 strongly interacts with the residues of His438 (residue of the catalytic triad) and Trp82 (residue of catalytic anionic site), confirming that this compound competes with the same binding site of the butyrylthiocholine

Novel arylcarbamate-N-acylhydrazones derivatives as promising BuChE inhibitors: Design, synthesis, molecular modeling and biological evaluation.

A novel series of arylcarbamate-N-acylhydrazones derivatives have been designed and synthesized as potential anti-cholinesterase agents. In vitro studies revealed that these compounds demonstrated selective for butyrylcholinesterase (BuChE) with potent inhibitory activity. The compounds 10a-d, 12b and 12d were the most potent BuChE inhibitors with IC50 values of 0.07-2.07 µM, highlighting the compound 10c (IC50 = 0.07 µM) which showed inhibitory activity 50 times greater than the reference drug donepezil (IC50 = 3.54 µM). The activity data indicates that the position of the carbamate group in the aromatic ring has a greater influence on the inhibitory activity of the derivatives. The enzyme kinetics studies indicate that the compound 10c has a non-competitive inhibition against BuChE with Ki value of 0.097 mM. Molecular modeling studies corroborated the in vitro inhibitory mode of interaction and show that compound 10c is stabilized into hBuChE by strong hydrogen bond interaction with Tyr128, π-π stacking interaction with Trp82 and CH⋯O interactions with His438, Gly121 and Glu197. Based on these data, compound10cwas identified as low-cost promising candidate for a drug prototype for AD treatment.

Membrane dynamics in Leishmania amazonensis and antileishmanial activities of ß-carboline derivatives.

Two ß-carboline compounds, 8i and 6d, demonstrated in vitro antileishmanial activity against Leishmania (L.) amazonensis promastigotes similar to that of miltefosine (MIL). Estimates of the membrane-water partition coefficient (KM/W) and the compound concentrations in the membrane (cm50) and aqueous phase (cw50) for half maximal inhibitory concentration were made. Whereas these biophysical parameters for 6d were not significantly different from those reported for MIL, 8i showed lower affinity for the parasite membrane (lower KM/W) and a lower concentration of the compound in the membrane required to inhibit the growth of the parasite (lower cm50). A 2-hour treatment of Leishmania promastigotes with the compounds 8i and 6d caused membrane rigidity in a concentration-dependent manner, as demonstrated by the electron paramagnetic resonance (EPR) technique and spin label method. This increased rigidity of the membrane was interpreted to be associated with the occurrence of cross-linking of oxidized cytoplasmic proteins to the parasite membrane skeleton. Importantly, the two ß-carboline-oxazoline derivatives showed low hemolytic action, both in experiments with isolated red blood cells or with whole blood, denoting their great Leishmania/erythrocyte selectivity index. Using electron microscopy, changes in the membrane of both the amastigote and promastigote form of the parasite were confirmed, and it was demonstrated that compounds 8i and 6d decreased the number of amastigotes in infected murine macrophages. Furthermore, 8i and 6d were more toxic to the protozoa than to J774A.1 macrophages, with treated promastigotes exhibiting a decrease in cell volume, mitochondrial membrane potential depolarization, accumulation of lipid bodies, increased ROS production and changes in the cell cycle.

Synthesis, antileishmanial activity and mechanism of action studies of novel ß-carboline-1,3,5-triazine hybrids.

A series of novel hybrids ß-carboline-1,3,5-triazine were synthesized and evaluated for their in vitro antileishmanial activity against promastigote and amastigote forms of Leishmania amazonensis. Among the compounds tested, the hybrids 9d, 9e, 16a and 16b showed potent activity against the promastigote forms with IC50 values less than 8 µM. Compounds 9e and 16b were also active against amastigote forms, displaying IC50 values of 1.0 ±â€¯0.1 µM and 1.2 ±â€¯0.5 µM, respectively. Besides that, the hybrid 16b bearing the 4-methoxyphenyl group at C-1 of ß-carboline and isopropylamino group at 1,3,5-triazine, showed low toxicity, being 23.5 and 121.4 times more toxic for promastigotes and axenic amastigotes, respectively, than for macrophage J774-A1 cell lines. Investigation of action mechanism in promastigotes showed that compound 16b caused alterations in cell division cycle and an increase of lipid-storage bodies, leading the cells to death through various factors. The accumulation of lipid bodies may be associated with apoptotic cell death.

Synthesis and evaluation of novel hybrids ß-carboline-4-thiazolidinones as potential antitumor and antiviral agents.

A series of novel hybrids ß-carboline-4-thiazolidinones were synthesized and evaluated for their in vitro antitumor activity against human cancer cell lines and for antiviral activity towards Herpes simplex virus type-1 (HSV-1). From the N'-(2-ylidene-4-thiazolidinone)-ß-carboline-3-carbohydrazide series (9-11), compounds 9c and 11d were the most active, showing growth inhibition 50% (GI50) values less than 5 µM for all cell lines tested. Compound 9c, bearing the 4-dimethylaminophenyl group at C-1 of ß-carboline was selected for further investigation concerning cell death and cell cycle profile, focusing on the human renal adenocarcinoma cell line 786-0. Treatments with 25 µM of compound 9c induced cell death after 15 h of treatment, characterized by phosphatidylserine exposure and loss of membrane integrity. Moreover, treatment with 12.5 µM promoted a sub-G1 arrest, which indicates cell death. Derivatives of the N-(2-substituted-aryl-4-thiazolidinone)-ß-carboline-3-carboxamide series (18-23) showed a potent activity and high selectivity for glioma (U251) and ovarian (OVCAR-3) cancer cell lines. Also, some ß-carboline-4-thiazolidinone hybrids showed potent antiviral activity against Herpes simplex virus type-1. The N-(2-substituted-aryl-4-thiazolidinone)-carboxamide moiety in 18, 19 and 22 confer a potent anti-HSV-1 activity for these derivatives, which presented EC50 values of 0.80, 2.15 and 2.02 µM, respectively. The assay results showed that the nature of 4-thiazolidinone moiety and of the substituent attached at the 3- and 1- position of ß-carboline nucleus influenced the antitumor and antiviral activities.