Design, synthesis and anticancer evaluation of novel Se-NSAID hybrid molecules: Identification of a Se-indomethacin analog as a potential therapeutic for breast cancer

Design, Synthesis, Anti-Proliferative, and Apoptotic Assessment of Spirocyclopropyl Oxindole-Isatin Hybrids on Triple-Negative Breast Cancer

A series of 1H-1,2,3-triazole-tethered spirocyclopropyl oxindole-isatin hybrids were synthesized using a copper-promoted click reaction and evaluated for their anti-proliferative activities against triple-negative breast cancer cell lines. The most potent compound in the series outperformed tamoxifen and 5-fluorouracil, with selectivity indices of 1.60 and 1.99 against MDA-MB-468 and MDA-MB-231 cancer cells, respectively. The Caspase 3/7 7-AAD assay showed live cell populations of 72.10% and 49.20% after 24 and 48 h, respectively, indicating that the cytotoxic effect is mediated through the caspase apoptotic pathway. Molecular docking studies further suggested the compound's potential as an epidermal growth factor receptor inhibitor, highlighting its promise as a therapeutic agent.

Selenium in Action: Exploring the Biological Wonders of Hydroselenite Salts

Despite the wealth of data related to the advantages of formulating a wide range of compounds as salts to ameliorate their biological properties, there is scant information regarding the therapeutic potential of selenium (Se) salts. In this work, we have formulated six antibiotics as hydroselenite salts in order to compare their in vitro antibacterial and anticancer effects and evaluate if this approach could enhance their water solubility. In this regard, in almost all the cases, their solubility was increased by one order of magnitude. All the compounds were screened against a panel of three Gram-positive and three Gram-negative bacteria. Likewise, their antiproliferative activity was evaluated in breast, prostate, glioblastoma, and pancreatic cancer cell lines. Normal human dermal fibroblasts (NHDF) were used to determine their selectivity indexes (SI). Additionally, these novel hydroselenite salts were submitted to the National Cancer Institute (NCI) to study their antitumoral potential. Compounds SLT-2 and SLT-6 showed potent cytotoxicity against the glioblastoma cancer cell line, and their ability to induce apoptosis and reactive oxygen species (ROS) was further assessed. To conclude, we have demonstrated that the formulation of several antibiotics as hydroselenite salts could be a feasible approach to obtain biologically active compounds with an enhanced effect.

Selenocompounds as Potent Efflux Pump Inhibitors on Gram-positive Bacteria

In recent years, selenocompounds have gained increasing attention as potential anticancer and antibacterial agents. Several selenoderivatives have been confirmed to act as MDR efflux pump inhibitors, based on their in vitro results against the bacterial AcrAB-TolC system and the cancer MDR efflux pump P-glycoprotein. Efflux pumps can contribute directly or indirectly to the virulence of bacteria, as they can reduce the intracellular concentration of antibacterial substances by expelling them out of the cell. The present work aims to study the antibacterial and efflux pump inhibiting properties of four families of selenoesters, namely aspirin-selenoesters, phenone-selenoesters, hydroxy-selenoesters, and benzyl-selenoesters. The real-time ethidium bromide accumulation assay confirmed that these derivatives inhibited the efflux systems of methicillin-resistant Staphylococcus aureus (MRSA) without exerting any antibacterial effect. The relative expression of efflux pump gene of NorA transporter was also monitored in the presence of the most potent derivatives on reference S. aureus, finding that these derivatives could change the expression of the tested efflux pump gene. Regarding the anti-biofilm activity, aspirin-selenoesters, benzyl-selenoesters, and hydroxy-selenoesters could efficiently inhibit the biofilm production of the MRSA strain. It can be concluded that selenocompounds could act as efflux pump inhibitors, thus reducing the virulence of biofilm-producing bacteria.

Repurposing of Indomethacin and Naproxen as anticancer agents: progress from 2017 to present

Inflammation is strongly linked to cancer and is essential for the growth and development of tumors. Targeting inflammation and the mediators involved in the inflammatory process could therefore provide a suitable method for cancer prevention and therapy. Numerous studies have shown that inflammation can predispose tumors. Non-steroidal anti-inflammatory drugs (NSAIDs) can affect the tumor microenvironment through increasing apoptosis and chemo-sensitivity while decreasing cell migration. Since the development of novel drugs requires a significant amount of money and time and poses a significant challenge for drug discovery, there has been a recent increase in interest in drug repositioning or repurposing. The growing body of research suggests that drug repurposing is essential for the quicker and less expensive development of anticancer therapies. In order to set the course for potential future repositioning of NSAIDs for clinical deployment in the treatment of cancer, the antiproliferative activity of derivatives of Indomethacin and Naproxen as well as their mechanism of action and structural activity relationships (SARs) published in the time frame from 2017 to 2024 are summarized in this review.

Organoselenium Compounds in Medicinal Chemistry

The chemical and biological interest in this element and the molecules bearing selenium has been exponentially growing over the years. Selenium, formerly designated as a toxin, becomes a vital trace element for life that appears as selenocysteine and its dimeric form, selenocystine, in the active sites of selenoproteins, which catalyze a wide variety of reactions, including the detoxification of reactive oxygen species and modulation of redox activities. From the point of view of drug developments, organoselenium drugs are isosteres of sulfur-containing and oxygen-containing drugs with the advantage that the presence of the selenium atom confers antioxidant properties and high lipophilicity, which would increase cell membrane permeation leading to better oral bioavailability. This statement is the paramount relevance considering the big number of clinically employed compounds bearing sulfur or oxygen atoms in their structures including nucleosides and carbohydrates. Thus, in this article we have focused on the relevant features of the application of selenium in medicinal chemistry. With the increasing interest in selenium chemistry, we have attempted to highlight the most significant published data on this subject, mainly concentrating the analysis on the last years. In consequence, the recent advances of relevant pharmacological organoselenium compounds are discussed.

Rational Design and Synthesis of Isatin-Chalcone Hybrids Integrated with 1H-1,2,3-Triazole: Anti-Proliferative Profiling and Molecular Docking Insights

In this study, a series of isatin-chalcone linked triazoles were synthesized using Cu-promoted Azide-Alkyne Cycloaddition (CuAAC) reaction and evaluated for their cytotoxicity against various cancer cell lines. The most potent compound displayed approximately 2.5 times greater activity compared to both reference compounds against ovarian cancer cell lines. These findings were supported by caspase-mediated apoptosis and molecular docking analyses. Docking revealed comparable VEGFR-2 affinities for 5 b and 5-FU but highlighted stronger interaction of 5 b with EGFR, evident from its lower docking score. Overall, these results signify the notable anti-proliferative potential of most synthesized hybrids, notably emphasizing the efficacy of compound 5 b in suppressing cancer cell growth.

Selenization of Small Molecule Drugs: A New Player on the Board

There is an urgent need to develop safer and more effective modalities for the treatment of a wide range of pathologies due to the increasing rates of drug resistance, undesired side effects, poor clinical outcomes, etc. Throughout the years, selenium (Se) has attracted a great deal of attention due to its important role in human health. Besides, a growing body of work has unveiled that the inclusion of Se motifs into a great number of molecules is a promising strategy for obtaining novel therapeutic agents. In the current Perspective, we have gathered the most recent literature related to the incorporation of different Se moieties into the scaffolds of a wide range of known drugs and their feasible pharmaceutical applications. In addition, we highlight different representative examples as well as provide our perspective on Se drugs and the possible future directions, promises, opportunities, and challenges of this ground-breaking area of research.

Formulation Studies with Cyclodextrins for Novel Selenium NSAID Derivatives

Commercial cyclodextrins (CDs) are commonly used to form inclusion complexes (ICs) with different molecules in order to enhance their water solubility, stability, and bioavailability. Nowadays, there is strong, convincing evidence of the anticancer effect of selenium (Se)-containing compounds. However, pharmaceutical limitations, such as an unpleasant taste or poor aqueous solubility, impede their further evaluation and clinical use. In this work, we study the enhancement of solubility with CD complexes for a set of different nonsteroidal anti-inflammatory drug (NSAID) derivatives with Se as selenoester or diacyl diselenide chemical forms, with demonstrated antitumoral activity. The CD complexes were analyzed via nuclear magnetic resonance (NMR) spectroscopic techniques. In order to obtain additional data that could help explain the experimental results obtained, 3D models of the theoretical CD-compound complexes were constructed using molecular modeling techniques. Among all the compounds, I.3e and II.5 showed a remarkable increase in their water solubility, which could be ascribed to the formation of the most stable interactions with the CDs used, in agreement with the in silico studies performed. Thus, the preliminary results obtained in this work led us to confirm the selection of β and γ-CD as the most suitable for overcoming the pharmaceutical drawbacks of these Se derivatives.

Isatin-indoloquinoxaline click adducts with a potential to overcome platinum-based drug-resistance in ovarian cancer

Herein, a series of isatin tethered indolo[2,3-b]quinoxaline hybrids was synthesized by considering the pharmacophoric features of known DNA intercalators and topoisomerase II inhibitors. The anti-proliferative properties of the synthesized compounds were evaluated against ovarian cancer cell lines (SKOV-3 and Hey A8). Four of the compounds exhibited promising anti-proliferative activities, with one of them being 10-fold more potent than cisplatin against drug-resistant Hey A8 cells. Further investigations were carried out to determine the DNA intercalating affinities of the most active compounds as potential mechanisms for their anti-proliferative activities. ADMET in silico studies were performed to assess the physicochemical, pharmacokinetics, and toxicity parameters of active compounds. This study, to the best of our knowledge, is the first report on the potential of isatin-indoloquinoxaline hybrids as structural blueprints for the development of new DNA intercalators. Additionally, it explores their potential to circumvent platinum-based resistance in ovarian cancer.

Quantitative Structure-activity Relationship (QSAR) Modelling of Indomethacin Derivatives using Regression Analysis

BACKGROUND

Indomethacin is a non-steroidal anti-inflammatory drug (NSAID) used for medication to reduce fever, spondylitis, or shoulder pain. It mainly works by the inhibition of prostaglandins, the endogenous signaling molecules.

METHODS

Fifteen indomethacin derivatives have been analyzed in relation to their physicochemical and molecular properties. Two-dimensional (2D) structures of fifteen indomethacin derivatives were drawn using the ACD Lab Chem Sketch version. Most of the topological parameters, such as wiener index (W), mean wiener index (Wa), Balaban indices (J), Balaban centric index (BAC), and molecular connectivity (χ), were calculated by using E Dragon software. The most common molecular file formats accepted in EDragon software were SMILES notations created online by Babel software and 2D structures of various derivatives, which were converted into 3D optimized structures using online CORINA, provided by Molecular Networks GMBH. 3D structures of compounds were also drawn on Gauss View software for calculations of various density functional theory (DFT) based quantum chemical descriptors, such as total energy (TE), softness (S), hardness (η), chemical potential (μ), highest occupied molecular orbital energy (HOMO), and lowest unoccupied molecular orbital energy (LUMO). All species were fully optimized in the gas phase with a 6-31+G* basis set. The harmonic vibrational frequency calculations were used to confirm that the optimized structures were minima, as characterized by positive vibrational frequencies.

RESULTS

Combinations of various descriptors, such as D, ID, IOR, Log P, Mr, Mv, Mw, Pc, BAC, Pz, St, W, Wa, 0χ, 1χ, 2χ,3χ,4χ, 5χ, and Xeq have been found to be significant for modeling of activity. QSAR model no. 2: pIC50= -20.605 (±6.600) IOR - 0.747 (±0.454) I1 -5.083 (±3.478) Xeq + 51.647 optimized with empirical parameters with high statistical quality (R= 0.921, R2=0.848) was found to be the best model obtained.

CONCLUSION

The QSAR model obtained suggests that substituents with a lesser value of the index of refraction and less electronegative groups were favourable for the activity, whereas indomethacin derivatives with a CH2CH2NHCONH(CH2)3ONO2 group at R1 position were unfavourable for the activity. The results were critically discussed based on regression data and cross-validation techniques. Pogliani factor Q and the results of the LOO (leave-one-out) method confirmed the reliability and predictability of the proposed models that could be highly beneficial for the future designing of new analogues with higher potency.

Novel phenoxy-((phenylethynyl) selanyl) propan-2-ol derivatives as potential anticancer agents

Selenocompounds protect against damage to healthy cells and induce the death of tumor cells by apoptosis; for this reason, they are attractive compounds for cancer research. In the present study, two series of novel phenoxy-((phenylethynyl) selanyl) propan-2-ol derivatives were synthesized, and their anti-proliferation activities were evaluated. Of the 23 compounds synthesized, most showed potent anti-proliferative activity against human cancer cell lines. Specifically, compounds 3h, 3g, and 3h-2, which had a 2- or 4-position halogen substituent on 1-((phenylethynyl)selanyl)-3-phenoxypropan-2-ol, exhibited the best anti-proliferative activity against tumor cells. Flow cytometry demonstrated that 3h, 3g, and 3h-2 induced G2/M phase arrest and apoptosis in A549 cells. Cellular studies demonstrated that the induction of apoptosis by 3h correlated with changes in the expression of cell cycle-related proteins and apoptosis-related proteins. Xenograft tumor experiments in nude mice revealed that compound 3h has antitumor effects in vivo and no evident toxic effects in nude mice. In addition, compound 3h alleviated cisplatin-induced liver and kidney damage. These findings uncover the applicability of compound 3h as a novel lead compound for cancer treatment.

Stereo/regio-selective access to substituted 3-hydroxy-oxindoles with anti-proliferative assessment and in silico validation

The manuscript focuses on a highly stereo-/regioselective approach for synthesizing a diverse array of substituted-3-hydroxy-2-oxindoles. The synthesized compounds were subsequently subjected to anti-proliferative assessment against various cell lines, including colorectal carcinoma, ovarian cancer, and human metastatic melanoma cancer. The structural characterization of the synthesized scaffolds was unambiguously confirmed using X-ray diffraction analysis. Among the synthesized compounds, one compound demonstrated exceptional potency within the series. It exhibited 1.2, 2.12, and 1.55 times greater potency than cisplatin against the HCT116, OVCAR10, and 1205Lu cell lines, respectively. These results were further supported by in vitro caspase-mediated apoptosis studies. Molecular docking studies of these compounds on the target VEGFR2 protein revealed their binding capability.

Investigation of Gold Nanoparticle Naproxen-Derived Conjugations in Ovarian Cancer

Ovarian cancer, which is one of the most diagnosed cancer types among women, maintains its significance as a global health problem. Several drug candidates have been investigated for the potential treatment of ovarian cancer. Nonsteroidal anti-inflammatory drugs (NSAIDs) demonstrated anti-cancer activity through the inhibition of cyclooxygenase 2 (COX-2) and by inhibiting COX-2-dependent prostaglandin (PG) production. Naproxen is one of the most used NSAIDs and Naproxen-derived compounds (NDCs) may show potential treatment effects on cancer as chemotherapeutic drugs. Although there are successful drug development studies, the lack of solubility of these drug candidates in aqueous media results in limited bioavailability and high variability of patient responses during treatment. Low aqueous solubility is one of the main problems in the pharmaceutical industry in terms of drug development. Nanotechnology-based strategies provide solutions to hydrophobic drug limitations by increasing dispersion and improving internalization. In this study, two different NDCs (NDC-1 and NDC-2) bearing a thiosemicarbazide/1,2,4-triazole moiety were synthesized and tested for chemotherapeutic effects on ovarian cancer cells, which have a high COX-2 expression. To overcome the limited dispersion of these hydrophobic drugs, the drug molecules were conjugated to the surface of 13 nm AuNPs. Conjugation of drugs to AuNPs increased the distribution of drugs in aqueous media, and NDC@AuNP conjugates exhibited excellent colloidal stability for up to 8 weeks. The proposed system demonstrated an increased chemotherapeutic effect than the free drug counterparts with at least 5 times lower IC50 values. NDC@AuNP nanosystems induced higher apoptosis rates, which established a simple and novel way to investigate activity of prospective drugs in drug discovery research.

First Generation of Antioxidant Precursors for Bioisosteric Se-NSAIDs: Design, Synthesis, and In Vitro and In Vivo Anticancer Evaluation

The introduction of selenium (Se) into organic scaffolds has been demonstrated to be a promising framework in the field of medicinal chemistry. A novel design of nonsteroidal anti-inflammatory drug (NSAID) derivatives based on a bioisosteric replacement via the incorporation of Se as diacyl diselenide is reported. The antioxidant activity was assessed using the DPPH radical scavenging assay. The new Se-NSAID derivatives bearing this unique combination showed antioxidant activity in a time- and dose-dependent manner, and also displayed different antiproliferative profiles in a panel of eight cancer cell lines as determined by the MTT assay. Ibuprofen derivative 5 was not only the most antioxidant agent, but also selectively induced toxicity in all the cancer cell lines tested (IC50 < 10 µM) while sparing nonmalignant cells, and induced apoptosis partially without enhancing the caspase 3/7 activity. Furthermore, NSAID derivative 5 significantly suppressed tumor growth in a subcutaneous colon cancer xenograft mouse model (10 mg/kg, TGI = 72%, and T/C = 38%) without exhibiting any apparent toxicity. To our knowledge, this work constitutes the first report on in vitro and in vivo anticancer activity of an unprecedented Se-NSAID hybrid derivative and its rational use for developing precursors for bioisosteric selenocompounds with appealing therapeutic applications.

Synthesis, biological activity and mechanism of action of novel allosecurinine derivatives as potential antitumor agents

Cancer with low survival rates is the second main cause of death among all diseases in the world and consequently, effective antineoplastic agents are urgently needed. Allosecurinine is a plant-derived indolicidine securinega alkaloid shown bioactivity. The object of this study is to investigate synthetic allosecurinine derivatives with considerable anticancer capacity against nine human cancer cell lines as well as mechanism of action. We synthesized twenty-three novel allosecurinine derivatives and evaluated their antitumor activity against nine cancer cell lines for 72 h by MTT and CCK8 assays. FCM was applied to analyze the apoptosis, mitochondrial membrane potential, DNA content, ROS production, CD11b expression. Western blot was selected to analyze the protein expression. Structure-activity relationships were established and potential anticancer lead BA-3 which induced differentiation of leukemia cells towards granulocytosis at low concentration and apoptosis at high concentration was identified. Mechanism studies showed that mitochondrial pathway mediated apoptosis within cancer cells with cell cycle blocking was induced by BA-3. In addition, western blot assays revealed that BA-3 induced expression of the proapoptotic factor Bax, p21 and reduced the levels of antiapoptotic protein such as Bcl-2, XIAP, YAP1, PARP, STAT3, p-STAT3, and c-Myc. Collectively, BA-3 was a lead compound for oncotherapy at least in part, through the STAT3 pathway. These results were an important step in further studies on allosecurinine-based antitumor agent development.

Design, Synthesis and Antitumor Activity of Novel Selenium-Containing Tepotinib Derivatives as Dual Inhibitors of c-Met and TrxR

Cellular mesenchymal-epithelial transition factor (c-Met), an oncogenic transmembrane receptor tyrosine kinase (RTK), plays an essential role in cell proliferation during embryo development and liver regeneration. Thioredoxin reductase (TrxR) is overexpressed and constitutively active in most tumors closely related to cancer recurrence. Multi-target-directed ligands (MTDLs) strategy provides a logical approach to drug combinations and would adequately address the pathological complexity of cancer. In this work, we designed and synthesized a series of selenium-containing tepotinib derivatives by means of selenium-based bioisosteric modifications and evaluated their antiproliferative activity. Most of these selenium-containing hybrids exhibited potent dual inhibitory activity toward c-Met and TrxR. Among them, compound 8b was the most active, with an IC₅₀ value of 10 nM against MHCC97H cells. Studies on the mechanism of action revealed that compound 8b triggered cell cycle arrest at the G₁ phase and caused ROS accumulations by targeting TrxR, and these effects eventually led to cell apoptosis. These findings strongly suggest that compound 8b serves as a dual inhibitor of c-Met and TrxR, warranting further exploitation for cancer therapy.

Seleno-Analogs of Scaffolds Resembling Natural Products a Novel Warhead toward Dual Compounds

Nowadays, oxidative cell damage is one of the common features of cancer and Alzheimer's disease (AD), and Se-containing molecules, such as ebselen, which has demonstrated strong antioxidant activity, have demonstrated well-established preventive effects against both diseases. In this study, a total of 39 Se-derivatives were synthesized, purified, and spectroscopically characterized by NMR. Antioxidant ability was tested using the DPPH assay, while antiproliferative activity was screened in breast, lung, prostate, and colorectal cancer cell lines. In addition, as a first approach to evaluate their potential anti-Alzheimer activity, the in vitro acetylcholinesterase inhibition (AChEI) was tested. Regarding antioxidant properties, compound 13a showed concentration- and time-dependent radical scavenging activity. Additionally, compounds 14a and 17a showed high activity in the melanoma and ovarian cancer cell lines, with LD50 values below 9.2 µM. Interestingly, in the AChEI test, compound 14a showed almost identical inhibitory activity to galantamine along with a 3-fold higher in vitro BBB permeation (Pe = 36.92 × 10-6 cm/s). Molecular dynamics simulations of the aspirin derivatives (14a and 14b) confirm the importance of the allylic group instead of the propargyl one. Altogether, it is concluded that some of these newly synthesized Se-derivatives, such as 14a, might become very promising candidates to treat both cancer and AD.

Selenium-Containing Agents Acting on Cancer-A New Hope?

Selenium-containing agents are more and more considered as an innovative potential treatment option for cancer. Light is shed not only on the considerable advancements made in understanding the complex biology and chemistry related to selenium-containing small molecules but also on Se-nanoparticles. Numerous Se-containing agents have been widely investigated in recent years in cancer therapy in relation to tumour development and dissemination, drug delivery, multidrug resistance (MDR) and immune system-related (anti)cancer effects. Despite numerous efforts, Se-agents apart from selenocysteine and selenomethionine have not yet reached clinical trials for cancer therapy. The purpose of this review is to provide a concise critical overview of the current state of the art in the development of highly potent target-specific Se-containing agents.