Anti-cancer activity of di- and tri-organotin(IV) compounds with D-(+)-Galacturonic acid on human tumor cells

In vitro and in vivo activity of a novel oxamide-hydrazone hybrid derivative against triple-negative breast cancer

Triple-negative breast cancer is a subtype of breast cancer with poor clinical outcome, and currently, no effective targeted therapies are available. Since cancer develops owing to deregulation of apoptosis, employing therapeutic strategies with the ability to target the molecules involved in apoptosis induction would provide a valid approach to hinder tumor progression. Hydrazide-hydrazones and oxamide molecules are the subject of intense studies due to their anticancer effects via apoptosis induction. In the present study, we attempted to elucidate the mechanism of action of a synthesized compound (compound A) in inducing cell death. Annexin/PI and Western blotting analyses, DAPI staining, mitochondrial membrane potential probe, and flow cytometry were applied for the in vitro evaluations. 4T1 syngeneic mouse model and immunohistochemistry were used for the in vivo assessments. Compound A caused cell death by inducing apoptosis in MDA-MB-231 cells in a mitochondrial-dependent manner at high concentrations after 72 h of incubation. Compound A also impeded tumor growth in a 4T1 syngeneic mouse model as evidenced by hematoxylin and eosin staining of the tumors. Furthermore, it significantly diminished the expression of pro-caspase-3, Ki67, and CD31 markers in the tumor sections. Conclusively, this study for the first time reports the anti-cancer efficacy of compound A in both in vitro and in vivo models and its potential in the treatment of triple-negative breast cancer.

Phytochemical Profile, GC-MS Profiling and In Vitro Evaluation of Some Biological Applications of the Extracts of Origanum syriacum L. and Cousinia libanotica D.C

Indigenous to Lebanon, Origanum syriacum L. and Cousinia libanotica D.C. are notable plants in the Middle East, with O. syriacum known for its aromatic qualities and C. libanotica being less explored. Both plants have a significant role in traditional medicine for treating various ailments. This study aimed to evaluate the phytochemical composition and biological properties of the extracts from these plants. The extracts were obtained through cold maceration with solvents of increasing polarity. The ethyl acetate extract of O. syriacum exhibited the highest total polyphenol content. High-performance liquid chromatography (HPLC) identified fifteen compounds in both C. libanotica and O. syriacum extracts, whereas gas chromatography-mass spectrometry (GC-MS) analysis unveiled 179 volatile compounds. Notably, the O. syriacum-MeOH extract showed moderate antioxidant activity. Both plants' methanolic extracts demonstrated significant anti-Alzheimer's potential. The O. syriacum-dichloromethane and C. libanotica-cyclohexane extracts displayed the highest cytotoxicities against the HCT-116 cell line. For anti-proliferative activity against the Caco-2 cell line, the O. syriacum-methanol and C. libanotica-cyclohexane extracts were the most effective. This study provides valuable insights into the phytochemistry and potential therapeutic applications of extracts from these two oriental plant species.

From nature to cancer therapy: Evaluating the Streptomyces clavuligerus secondary metabolites for potential protein kinase inhibitors

The study aimed to evaluate the antioxidant, protein kinase inhibitory (PKIs) potential, cytotoxicity activity of Streptomyces clavuligerus extract. DPPH assay revealed a robust free radical scavenging capacity (IC50 28.90 ± 0.24 µg/mL) of organic extract with a maximum inhibition percentage of 61 ± 1.04%. PKIs assay revealed the formation of a whitish bald zone by S. clavuligerus extracts which indicates the presence of PKIs. The cytotoxicity activity of organic fraction of extract through Sulforhodamine B assay on MCF-7, Hop-62, SiHa, and PC-3 cell lines demonstrated the lowest GI50 value against the MCF-7 cell line followed by the PC-3 cell line, showing potent growth inhibitory potential against human breast cancer and human prostate cancer cell line. HR-LCMS analysis identified multiple secondary metabolites from the organic and aqueous extracts of S. clavuligerus when incubated at 30°C under 200 rpm for 3 days. All the secondary metabolites were elucidated for their potential to inhibit RTKs by molecular docking, molecular dynamic simulation, MM/GBSA calculations, and free energy approach. It revealed the superior inhibitory potential of epirubicin (Epi) and dodecaprenyl phosphate-galacturonic acid (DPGA) against fibroblast growth factors receptor (FGFR). Epi also exhibited excellent inhibitory activity against the platelet-derived growth factor receptor (PDGFR), while DPGA effectively inhibited the vascular endothelial growth factor receptor. Additionally, the presence Epi in S. clavuligerus extract was validated through the HPLC technique. Thus, our findings highlight a superior inhibitory potential of Epi against FGFR and PDGFR RTKs than the FDA-approved drug.

Biological Evaluation of Triorganotin Derivatives as Potential Anticancer Agents

Metal-derived platinum complexes are widely used to treat solid tumors. However, systemic toxicity and tumor resistance to these drugs encourage further research into similarly effective compounds. Among others, organotin compounds have been shown to inhibit cell growth and induce cell death and autophagy. Nevertheless, the impact of the ligand structure and mechanisms involved in the toxicity of organotin compounds have not been clarified. In the present study, the biological activities of commercially available bis(tributyltin) oxide and tributyltin chloride, in comparison to those of specially synthesized tributyltin trifluoroacetate (TBT-OCOCF₃) and of cisplatin, were assessed using cells with different levels of tumorigenicity. The results show that tributyltins were more cytotoxic than cisplatin in all the tested cell lines. NMR revealed that this was not related to the interaction with DNA but to the inhibition of glucose uptake into the cells. Moreover, highly tumorigenic cells were less susceptible than nontumorigenic cells to the nonunique pattern of death induced by TBT-OCOCF₃. Nevertheless, tumorigenic cells became sensitive when cotreated with wortmannin and TBT-OCOCF₃, although no concomitant induction of autophagy by the compound was detected. Thus, TBT-OCOCF₃ might be the prototype of a family of potential anticancer agents.

Study of the Polysaccharide Production by the Microalga Vischeria punctata in Relation to Cultivation Conditions

Vischeria punctata is a unicellular microalga that has industrial potential, as it can produce substances with beneficial properties. Among them, endopolysaccharides (accumulated in cells) and exopolysaccharides (released by cells into the culture medium) are of particular interest. This study aimed to investigate the effect of nutrient medium composition on the growth of V. punctata biomass and the synthesis of polysaccharides by microalgae. The effect of modifying a standard nutrient medium and varying cultivation parameters (temperature, time, and extractant type) on the yield of exopolysaccharides produced by the microalgae V. punctate was investigated. The methods of spectrophotometry, ultrasonic extraction, and alcohol precipitation were used in the study. It was found that after 61 days of cultivation, the concentration of polysaccharides in the culture medium was statistically significantly higher (p <0.05) when using a Prat nutrient medium (984.9 mg/g d.w.) than BBM 3N (63.0 mg/g d.w.). It was found that the increase in the V. punctata biomass when cultivated on different nutrient media did not differ significantly. The maximum biomass values on Prat and BBM 3N media were 1.101 mg/g d.w. and 1.120 mg/g d.w., respectively. Neutral sugars and uronic acids were found in the culture media. It follows on from the obtained data that the modified PratM medium was more efficient for extracting polysaccharides from V. punctata. The potential of microalgae as new sources of valuable chemicals (polysaccharides), which can be widely used in technologies for developing novel functional foods, biologically active food supplements, and pharmaceutical substances, was studied.

Aroylhydrazone Diorganotin Complexes Causes DNA Damage and Apoptotic Cell Death: From Chemical Synthesis to Biochemical Effects

Under microwave irradiation, eighteen new aroylhydrazone diorganotin complexes (1a–9b) were produced through the reaction of aroylhydrazine, 2-ketobutyric acid, and the corresponding diorganotin. Fourier transform infrared spectroscopy, ¹H, ¹³C, and ¹¹⁹Sn nuclear magnetic resonance spectroscopies, high-resolution mass spectroscopy, X-ray crystallography, and thermogravimetric analysis (TGA) were performed to characterize the complexes. The in vitro anticancer activity for complexes were assessed using a CCK-8 assay on human cancer cells of HepG2, NCI-H460, and MCF-7. Complex 4b revealed more intensive anticancer activity against MCF-7 cells than the other complexes and cisplatin. Flow cytometry analysis and transmission electron microscope observation demonstrated that complex 4b mediated cell apoptosis of MCF-7 cells and arrested cell cycle in S phase. Western blotting analysis showed that 4b induced DNA damage in MCF-7 cells and led to apoptosis by the ATM-CHK2-p53 pathway. The single cell gel electrophoreses assay results showed that 4b induced DNA damage. The DNA binding activity of 4b was studied by UV–Visible absorption spectrometry, fluorescence competitive, viscosity measurements, gel electrophoresis, and molecular docking, and the results show that 4b can be well embedded in the groove and cleave DNA.

Synthesis of 4-thiol-furanosidic uronate via hydrothiolation reaction

Uronic acids are not only important building blocks of polysaccharides and oligosaccharides but also are widely used in the food and pharmaceutical industries. Inspired by the structure of natural products, here, we disclosed base-mediated and radical-mediated hydrothiolation reactions for the preparation of thiol-contained uronates. In comparison with base-mediated reaction, radical-mediated hydrothiolation is inefficient due to the electron-withdrawing group on the ethylene group; nevertheless, the adduct had excellent stereoselectivity at both C-4 and C-5 positions. For the alkaline approach, thiols as nucleophiles can regioselectively and stereoselectively attach to the C-4 position of Δ-^4,5-unsaturated uronate with moderate to good yields. However, poor stereoselectivity at the C-5 position was observed due to retro thiol-Michael addition. After removing the protecting group of the thiol, the thiol adduct was isomerized to the furanosidic form and the 4-thiol-furanosidic uronate derivative was synthesized for the first time.

Uronic acids are not only important building blocks of bioactive molecules but also are widely used in the food and pharmaceutical industries. Its derivative, 4-thiol-furanosidic uronate was successfully synthesized and firstly reported here.

Novel triorganotin complexes based on phosphonic acid ligands: Syntheses, structures and in vitro cytostatic activity

Six novel organotin phosphonate complexes, [(Me₃Sn)₄(HL¹)₄]_n1, [(Me₃Sn)₂(HL²)₂]_n2, [(Me₃Sn)₂L³(H₂O)]_n3, [(Ph₃Sn)(HL¹)]₆4, [(Ph₃Sn)₂L²]_n5 and [(Ph₃Sn)₂L³]₆6, derived from phosphonic acid ligands [NaHL¹ = 1-C₁₀H₇OPO₂(OH)Na, H₂L² = 1-C₁₀H₇PO(OH)₂, H₂L³ = 2-C₁₀H₇PO(OH)₂], have been synthesized and characterized by elemental analysis, FT-IR, NMR (¹H, ¹³C, ³¹P and ¹¹⁹Sn) spectroscopy and X-ray crystallography. The structural analysis reveals that complexes 1 and 5 display 1D infinite zig-zag chain structures, and complex 2 shows 1D right-handed helical chain structure, while complex 3 displays 1D left-handed helical chain structure. Complexes 4 and 6 are 24-membered macrocyclic rings interconnected by P, O and Sn atoms. Additionally, the molecules of complexes 1 and 3 are further linked through intermolecular π···π and O-H···O interaction into supramolecular structures, respectively. Furthermore, we preliminarily estimated in vitro cytostatic activity of complexes 1-6 against the human cervix tumor cells (HeLa), human hepatocellular carcinoma cells (HepG-2) and human normal breast cells (HBL-100). Importantly, the anti-proliferative properties and possible pathway of complex 6 are investigated, and the results demonstrate that complex 6 could induce apoptotic cell death via an overload of intracellular reactive oxygen species (ROS) levels and the dysfunctional depolarization of mitochondrial membranes.

Diversity of complexes based on p-nitrobenzoylhydrazide, benzoylformic acid and diorganotin halides or oxides self-assemble: Cytotoxicity, the induction of apoptosis in cancer cells and DNA-binding properties

Eight organotin(IV) complexes (C1-C8) have been synthesized and characterized by elemental analysis, fourier transform infrared spectroscopy (FT-IR), multinuclear nuclear magnetic resonance (¹H, ¹³C and ¹¹⁹Sn NMR), high resolution mass spectroscopy (HRMS) and single crystal X-ray structural analysis. Crystallographic data show that C1 was a tetranuclear 16-membered macrocycle complex, C2-C4 and C7 were centrosymmetric dimer distannoxane and there was a Sn₂O₂ four-membered ring in the middle of the molecule, respectively, C5 and C6 are monoorganotin complexes due to the dehydroalkylation effect during the reaction, while C8 forms a one-dimensional chain structure. The cytotoxicity of all complexes were tested by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assays against three human tumor cell lines NCI-H460, MCF-7 and HepG2. The dibutyltin complex C2 has been shown to be more potent antitumor agents than other complexes and carboplatin. Cell apoptosis study of C2 with the high activity on HepG2 and MCF-7 cancer cell lines was investigated by flow cytometry, it was shown that the antitumor activity of C2 was related to apoptosis, but it has different cell cycle arrest characteristics from platinum compounds, and the proliferation was inhibited by blocking cells in S phase. The DNA binding activity of the C2 was studied by UV-visible absorption spectrometry, fluorescence competitive, viscosity measurements and gel electrophoresis, results shown C2 can be well embedded in the double helix of DNA and cleave DNA.

Volatile Compounds Are Involved in Cellular Crosstalk and Upregulation

Cell-cell cross talk is of great importance in cancer research due to its major role in proliferation, differentiation, migration, and influence on the apoptotic pathway. Different cell-cell communication mechanisms have come mainly from proteomic and genomic approaches. In this paper, a new route is reported for cross talk between cancer cells that occurs, even when they are far away from each other. Single-cell and culture analysis shows that upregulation of cancer cells emits hundreds of volatile organic compounds (VOCs) into their headspace. Part of the VOCs remains without any change, disregarding the biological environment around it. The other part of the VOCs is exchanged between monocultures of the cells as well as between co-cultures of the cells with no physical contact between them, leading to different changes in growth than when left on their own. The chemical nature and composition of these VOCs have been determined and are discussed herein. Cell-to-cell cross talk has the advantage of being suitable for transfer/diffusion over relatively long distances. It would thus be expected to serve as a shuttling pad toward the development of advanced approaches that could enable very early detection of cancer and/or monitoring of metastasis and related cancer therapy.

Anti-proliferative and antitumor activity of organotin(IV) compounds. An overview of the last decade and future perspectives

Organotins(IV) exhibit significant in vitro anti-proliferative activity, while the in vivo tests are encouraging. The recent reports on the anti-proliferative activity of organotin(IV) compounds are summarized in this review. The period covered by this work goes back to 2009 until late 2018, while the earlier ones, are included over the previous review of our group published by S.K. Hadjikakou, N. Hadjiliadis, in Coord Chem Rev, 253 (2009) 235-249. During the last decade (2009-2018), >300 organotin(IV) derivatives with oxygen-donor ligands, such as carboxylic acids, amino-acids, Non Steroidal Anti-inflammatory Drugs (NSAIDs), biological active derivatives or natural products, organotins(IV) with sulfur containing ligands such as thiones, thiosemicarbazones, dithiocarbamates, organotin(IV) compounds of oximes and organotins(IV) with amines or semicarbazones were screened for their anti-proliferative effect against various cancer cell lines and their results are included in numerous reports over this period. Although much work has been carried out on organotin(IV) derivatives with O-donor ligands, however significant fewer reports are found on organotins(IV) with oximes as ligands.