Pre-clinical evidences of the antileishmanial effects of diselenides and selenocyanates.

A series of thirty-one selenocompounds covering a wide chemical space was assessed for in vitro leishmanicidal activities against Leishmania infantum amastigotes. The cytotoxicity of those compounds was also evaluated on human THP-1 cells. Interestingly most tested derivatives were active in the low micromolar range and seven of them (A.

Synthesis and Leishmanicidal Activity of Novel Urea, Thiourea, and Selenourea Derivatives of Diselenides.

A novel series of thirty-one N-substituted urea, thiourea, and selenourea derivatives containing diphenyldiselenide entities were synthesized, fully characterized by spectroscopic and analytical methods, and screened for their leishmanicidal activities. The cytotoxic activity of these derivatives was tested against axenic amastigotes, and selectivity was assessed in human THP-1 cells. Thirteen of the synthesized compounds showed a significant antileishmanial activity, with 50% effective concentration (EC) values lower than that for the reference drug miltefosine (EC, 2.

Identification of a Novel Quinoxaline-Isoselenourea Targeting the STAT3 Pathway as a Potential Melanoma Therapeutic.

The prognosis for patients with metastatic melanoma remains very poor. Constitutive signal transducer and activator of transcription 3 (STAT3) activation has been correlated to metastasis, poor patient survival, larger tumor size, and acquired resistance against vemurafenib (PLX-4032), suggesting its potential as a molecular target. We recently designed a series of isoseleno- and isothio-urea derivatives of several biologically active heterocyclic scaffolds.

Novel Methylselenoesters Induce Programed Cell Death via Entosis in Pancreatic Cancer Cells.

Redox active selenium (Se) compounds have gained substantial attention in the last decade as potential cancer therapeutic agents. Several Se compounds have shown high selectivity and sensitivity against malignant cells. The cytotoxic effects are exerted by their biologically active metabolites, with methylselenol (CH₃SeH) being one of the key executors.

A diphenyldiselenide derivative induces autophagy via JNK in HTB-54 lung cancer cells.

Symmetric aromatic diselenides are potential anticancer agents with strong cytotoxic activity. In this study, the in vitro anticancer activities of a novel series of diarylseleno derivatives from the diphenyldiselenide (DPDS) scaffold were evaluated. Most of the compounds exhibited high efficacy for inducing cytotoxicity against different human cancer cell lines.

Novel Methylselenoesters as Antiproliferative Agents.

Selenium (Se) compounds are potential therapeutic agents in cancer. Importantly, the biological effects of Se compounds are exerted by their metabolites, with methylselenol (CH₃SeH) being one of the key executors. In this study, we developed a new series of methylselenoesters with different scaffolds aiming to modulate the release of CH₃SeH.

Topological and quantum molecular descriptors as effective tools for analyzing cytotoxic activity achieved by a series of (diselanediyldibenzene-4,1-diylnide)biscarbamate derivatives.

A molecular modeling study has been carried out on a previously reported series of (diselanediyldibenzene-4,1-diylnide)biscarbamate derivatives that show cytotoxic and antiproliferative in vitro activity against MCF-7 human cell line; radical scavenging properties were also confirmed when these compounds were tested for their ability to scavenge DPPH and ABTS radicals. The data obtained allowed us to classify the compounds into two different groups: (a) aliphatic carbamates for which the activity could be related with a first nucleophilic attack (mediated by HO, for example) on the selenium atoms of the central scaffold, followed by the release of the alkyl N-(4-selanylphenyl) and N-(4-selenenophenyl)carbamate moieties. Then, a second nucleophilic attack on the carbamate moiety, to yield 4-aminobenzeneselenol and 4-selenenoaniline respectively, which can ultimately be responsible for the activity of the compounds; (b) aromatic carbamates, for which we propose a preferred nucleophilic attack on the carbamate moiety, yielding 4-[(4-aminophenyl)diselanyl]aniline, the common structural fragment for this series, for which we have previously demonstrated its cytotoxic profile.

Chalcogen containing heterocyclic scaffolds: New hybrids with antitumoral activity.

In this work, 27 novel hybrid derivatives containing diverse substituents with chalcogen atoms (selenium or sulfur) and several active heterocyclic scaffolds have been synthesized. Compounds were tested against two human cancer cells lines (MCF7 and PC-3) and a normal human mammary epithelial cell line (184B5) in order to determine their activity and selectivity against malignant cells. Ten compounds showed GI50 values below 10 μM in at least one of the cancer cell lines and six of them exhibited a selectivity index higher than 9.

Identification of selenocompounds with promising properties to reverse cancer multidrug resistance.

In previous studies, 56 novel selenoesters and one cyclic selenoanhydride with chemopreventive, antiproliferative and cytotoxic activity were described. Herein, the selenoanhydride and selected selenoesters were evaluated for their ability to reverse the cancer multidrug resistance (MDR) using the ABCB1 efflux pump inhibition assay in mouse MDR T-lymphoma cells. Results showed that the selenoanhydride (1) and the selenoesters with ketone terminal fragments (9-11) exerted (1.

Novel Heteroaryl Selenocyanates and Diselenides as Potent Antileishmanial Agents.

A series of new selenocyanates and diselenides bearing interesting bioactive scaffolds (quinoline, quinoxaline, acridine, chromene, furane, isosazole, etc.) was synthesized, and their in vitro leishmanicidal activities against Leishmania infantum amastigotes along with their cytotoxicities in human THP-1 cells were determined. Interestingly, most tested compounds were active in the low micromolar range and led us to identify four lead compounds (1h, 2d, 2e, and 2f) with 50% effective dose (ED50) values ranging from 0.

Novel seleno- and thio-urea derivatives with potent in vitro activities against several cancer cell lines.

A series of novel selenourea derivatives and corresponding thiourea analogs were synthesized and tested against a panel of six human cancer cell lines: melanoma (1205Lu), lung carcinoma (A549), prostatic carcinoma (DU145), colorectal carcinoma (HCT116), pancreatic epithelioid carcinoma (PANC-1) and pancreatic adenocarcinoma (BxPC3). In general, we found that the selenium-containing derivatives were more potent than their isosteric sulfur analogs. Four selenourea derivatives (1e, 1f, 1g and 1i) showed IC50 values below 10 μM in all of tested cell lines at 72 h.

Leishmanicidal activities of novel methylseleno-imidocarbamates.

The generation of new antileishmanial drugs has become a priority. Selenium and its derivatives stand out as having promising leishmanicidal activity. In fact, some parasites express selenoproteins and metabolize selenium.

Molecular descriptors calculation as a tool in the analysis of the antileishmanial activity achieved by two series of diselenide derivatives. An insight into its potential action mechanism.

A molecular modeling study has been carried out on two previously reported series of symmetric diselenide derivatives that show remarkable antileishmanial in vitro activity against Leishmania infantum intracellular amastigotes and in infected macrophages (THP-1 cells), in addition to showing favorable selectivity indices. Series 1 consists of compounds that can be considered as central scaffold constructed with a diaryl/dialkylaryl diselenide central nucleus, decorated with different substituents located on the aryl rings. Series 2 consists of compounds constructed over a diaryl diselenide central nucleus, decorated in 4 and 4' positions with an aryl or heteroaryl sulfonamide fragment, thus forming the diselenosulfonamide derivatives.

In vitro radical scavenging and cytotoxic activities of novel hybrid selenocarbamates.

Novel selenocyanate and diselenide derivatives containing a carbamate moiety were synthesised and evaluated in vitro to determine their cytotoxic and radical scavenging properties. Cytotoxic activity was tested against a panel of human cell lines including CCRF-CEM (lymphoblastic leukaemia), HT-29 (colon carcinoma), HTB-54 (lung carcinoma), PC-3 (prostate carcinoma), MCF-7 (breast adenocarcinoma), 184B5 (non-malignant, mammary gland derived) and BEAS-2B (non-malignant, derived from bronchial epithelium). Most of the compounds displayed high antiproliferative activity with GI50 values below 10μM in MCF-7, CCRF-CEM and PC-3 cells.

Synthesis and antiproliferative activity of novel methylselenocarbamates.

A series of new aliphatic, aromatic and heteroaromatic carbamate derivatives containing a methylseleno moiety were synthesized and evaluated in vitro for their cytotoxic activity against a panel of human cell lines including CCRF-CEM (lymphoblastic leukaemia), K-562 (lymphocytic leukaemia), HT-29 (colon carcinoma), HTB-54 (lung carcinoma), PC-3 (prostate carcinoma), MCF-7 (breast adenocarcinoma), 184B5 (non-malignant, mammary gland derived) and BEAS-2B (non-malignant, derived from bronchial epithelium). Most of the compounds are highly cytotoxic with GI50 values below 10 μM in every tested tumour cell line. Based on its cytotoxic parameters, selectivity index and ADME profile, the biological activity of compound 2, the propyl derivative, was further analysed in CCRF-CEM and HTB-54 cells.

A dihydroselenoquinazoline inhibits S6 ribosomal protein signalling, induces apoptosis and inhibits autophagy in MCF-7 cells.

The PI3K/Akt/mTOR/S6 ribosomal protein signalling pathway is a key potential target in breast cancer therapy, playing a central role in proliferation and cell survival. In this study, we found that the seleno-compound 2,4-dihydroselenoquinazoline (3a) generally inhibited this signalling axis in MCF-7 breast cancer cells and caused downregulation of S6 ribosomal protein phosphorylation in a dose- and time-dependent manner. Furthermore, 3a caused a dose- and time-dependent decrease in MCF-7 cell viability as well as cell cycle arrest in G2/M.

Novel hybrid selenosulfonamides as potent antileishmanial agents.

Diselenide and sulfonamide derivatives have recently attracted considerable interest as leishmanicidal agents in drug discovery. In this study, a novel series of sixteen hybrid selenosulfonamides has been synthesized and screened for their in vitro activity against Leishmania infantum intracellular amastigotes and THP-1 cells. These assays revealed that most of the compounds exhibited antileishmanial activity in the low micromolar range and led us to identify three lead compounds (derivatives 2, 7 and 14) with IC50 values ranging from 0.

Synthesis and antiproliferative activity of novel selenoester derivatives.

A series of 31 new selenoesters were synthesized and their cytotoxic activity was evaluated against a prostate cancer cell line (PC-3). The most active compounds were also tested against three tumoural cell lines (MCF-7, A-549 and HT-29) and one non-tumour prostate cell line (RWPE-1). Thirteen compounds showed significant activity towards all tumour cells investigated, and some of them were even more potent than etoposide and cisplatin, which were used as reference drugs.

Bisacylimidoselenocarbamates cause G2/M arrest associated with the modulation of CDK1 and Chk2 in human breast cancer MCF-7 cells.

Bisacylimidoselenocarbamate derivatives (BSC) are potent anticancer agents with a strong cytotoxic activity against different types of tumour cells. Based in phosphatidylserine exposure on the cell membranes we show that BSC treatment resulted in enhanced cell death in leukaemia CCRF-CEM cells. DNA fragmentation detection in breast adenocarcinoma MCF-7 cells showed that BSC triggered cell death is concentration and time dependent.

Structure- and cell-specific effects of imidoselenocarbamates on selenoprotein expression and activity in liver cells in culture.

The essential micronutrient selenium (Se) exerts its biological effects mainly through selenoproteins thereby affecting a number of physiological pathways including intracellular redox control, stress response and cancer cell proliferation. Besides affecting selenoprotein expression, some selenocompounds have been synthesized and analyzed in order to serve as chemotherapeutic substances preferentially targeting cancer cells. This promising chemotherapeutic potential has recently been verified for a particular imidoselenocarbamate in a mouse tumor model.

Selenium compounds, apoptosis and other types of cell death: an overview for cancer therapy.

Selenium (Se) is an essential trace element involved in different physiological functions of the human body and plays a role in cancer prevention and treatment. Induction of apoptosis is considered an important cellular event that can account for the cancer preventive effects of Se. The mechanisms of Se-induced apoptosis are associated with the chemical forms of Se and their metabolism as well as the type of cancer studied.

Novel structural insights for imidoselenocarbamates with antitumoral activity related to their ability to generate methylselenol.

In the search for molecules with potential antiangiogenic activity we found that several imidoselenocarbamate derivatives, which have pro-apoptotic and antiproliferative activities, under hypoxic conditions release methylselenol, a volatile and highly reactive gas that was considered to be responsible for the observed biological activity. The kinetic for the liberation of methylselenol is highly dependent on the nature of the overall structure and correlate with their proven pro-apoptotic activity in lung cancer cell line H157. The preliminary structure-activity relationships allow us to select as the basic structural element a scaffold constructed with an imidoselenocarbamate fragment decorated with a methyl residue on the Se central atom and two heteroaromatic lateral rings.

Sulfur and selenium derivatives of quinazoline and pyrido[2,3-d]pyrimidine: synthesis and study of their potential cytotoxic activity in vitro.

The synthesis, cytotoxic activities and selectivities of 35 derivatives related to quinazoline and pyrido[2,3-d]pyrimidine are described. The synthesized compounds were screened in vitro against four tumoral cell lines - leukemia (CCRF-CEM), colon (HT-29), lung (HTB-54) and breast (MCF-7) - and two cell lines derived from non-malignant cell lines, one mammary (184B5) and one from bronchial epithelium (BEAS-2B). MCF-7 and HTB-54 were the most sensitive cell lines with GI(50) values below 10μM for eleven and ten compounds, respectively.

Novel library of selenocompounds as kinase modulators.

Although the causes of cancer lie in mutations or epigenic changes at the genetic level, their molecular manifestation is the dysfunction of biochemical pathways at the protein level. The 518 protein kinases encoded by the human genome play a central role in various diseases, a fact that has encouraged extensive investigations on their biological function and three dimensional structures. Selenium (Se) is an important nutritional trace element involved in different physiological functions with antioxidative, antitumoral and chemopreventive properties.

New insights into the structural requirements for pro-apoptotic agents based on 2,4-diaminoquinazoline, 2,4-diaminopyrido[2,3-d]pyrimidine and 2,4-diaminopyrimidine derivatives.

As a continuation of our work on new anti-tumoral derivatives with selective pro-apoptotic activity in cancer cells, we describe the synthesis and the preliminary evaluation of the cytotoxic and pro-apoptotic activities of a series of pyrimidin-2,4-diamine derivatives that are structurally related to quinazolin-2,4-diamine and pyrido[2,3-d]pyrimidin-2,4-diamine derivatives. We also describe the structure-activity relationship studies carried out on four series' of quinazolin-2,4-diamine, 2-(alkylsulfanyl)-N-alkyl- and 2-(alkylsulfanyl)-N-alkylarylpyrido[2,3-d]pyrimidine and pyrimidin-2,4-diamine derivatives. The proposed preliminary pharmacophore consists of a flat heterocyclic ring, preferably a pyrido[2,3-d]pyrimidine, with two equivalent alkylarylamine chains, preferably N-benzyl- or N-ethylphenylamine, located in positions 2 and 4 of the ring, and with a preferred ALogP in the range 4.