Optically pure chiral copper(II) complexes of rosin derivative as attractive anticancer agents with potential anti-metastatic and anti-angiogenic activities

Antiproliferative activity of platinum(II) and copper(II) complexes containing novel biquinoxaline ligands

Nowadays, cancer represents one of the major causes of death in humans worldwide, which renders the quest for new and improved antineoplastic agents to become an urgent issue in the field of biomedicine and human health. The present research focuses on the synthesis of 2,3,2',3'-tetra(pyridin-2-yl)-6,6'-biquinoxaline) and (2,3,2',3'-tetra(thiophen-2-yl)-6,6'-biquinoxaline) containing copper(II) and platinum(II) compounds as prodrug candidates. The binding interaction of these compounds with calf thymus DNA (CT-DNA) and human serum albumin were assessed with UV titration, thermal decomposition, viscometric, and fluorometric methods. The thermodynamical parameters and the temperature-dependent binding constant (K'b) values point out to spontaneous interactions between the complexes and CT-DNA via the van der Waals interactions and/or hydrogen bonding, except Cu(ttbq)Cl2 for which electrostatic interaction was proposed. The antitumor activity of the complexes against several human glioblastomata, lung, breast, cervix, and prostate cell lines were investigated by examining cell viability, oxidative stress, apoptosis-terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, in vitro migration and invasion, in vitro-comet DNA damage, and plasmid DNA interaction assays. The U87 and HeLa cells were investigated as the cancer cells most sensitive to our complexes. The exerted cytotoxic effect of complexes was attributed to the formation of the reactive oxygen species in vitro. It is clearly demonstrated that Cu(ttbq)Cl2, Pt(ttbq)Cl2, and Pt(tpbq)Cl2 have the highest DNA degradation potential and anticancer effect among the tested complexes by leading apoptosis. The wound healing and invasion analysis results also supported the higher anticancer activity of these two compounds.

Xylan derived fluorescence carbon dots composite with cotton cellulose paper as 'turn-off' fluorescence platform for sensitive and selective detection Cu2+ in real samples

The pollution of heavy metals such as Cu2+ is still serious and the discharge of sewage of Cu2+ will cause damage to soil environment and human health. Herein, a biomass-based solid-state fluorescence detection platform (CPU-CDs) was developed as fluorescent sensor for detection Cu2+ via fluorescence and colorimetric dual-model methods in real time. CPU-CDs was composed of xylan-derived CDs (U-CDs) and cotton cellulose paper, which exhibiting good reusability, non-toxicity, excellent fluorescence characteristics and high biocompatibility. Further, CPU-CDs displayed high effectiveness and sensitivity for Cu2+ with the detection limit as low as 0.14 μM, which was well below U.S. EPA safety levels (20 μM). Practical application indicated that CPU-CDs could achieve precision response of Cu2+ change in real environment water samples with good recovery range of 90 %-119 %. This strategy demonstrated a promising biomass solid-state fluorescence sensor for Cu2+ detection for water treatment research, which is of great significance in dealing with water pollution caused by heavy metal ions.

Disparities in Cisplatin-Induced Cytotoxicity-A Meta-Analysis of Selected Cancer Cell Lines

Cisplatin is a classic anticancer drug widely used as a reference drug to test new metal complex drug candidates. We found an unexpected diversity in cisplatin-related cytotoxicity values, expressed as IC50 (the half-maximal inhibitory concentration) in tumour cell lines, such as MCF-7, HepG2 and HeLa. We reviewed the data published from 2018 to 2022. A total of 41 articles based on 56 in vitro experiments met our eligibility criteria. Using a meta-analysis based on a random effect model, we evaluated the cytotoxicity of cisplatin (IC50) after 48- or 72-h cell exposure. We found large differences between studies using a particular cell line. According to the random effect model, the 95% confidence intervals for IC50 were extremely wide. The heterogeneity of cisplatin IC50, as measured by the I2 index for all cancer cell lines, was over 99.7% at culture times of 48 or 72 h. Therefore, the variability between studies is due to experimental heterogeneity rather than chance. Despite the higher IC50 values after 48 h than after 72 h, the heterogeneity between the two culture periods did not differ significantly. This indicates that the duration of cultivation is not the main cause of heterogeneity. Therefore, the available data is diverse and not useful as a reference. We discuss possible reasons for the IC50 heterogeneity and advise researchers to conduct preliminary testing before starting experiments and not to solely rely on the published data. We hope that this systematic meta-analysis will provide valuable information for researchers searching for new cancer drugs using cisplatin as a reference drug.

A novel water-soluble Cu(II) gluconate complex inhibits cancer cell growth by triggering apoptosis and ferroptosis related mechanisms

Metal copper complexes have attracted extensive attention as potential alternatives to platinum-based anticancer drugs due to their possible different modes of action. Herein, a new copper(II) gluconate complex, namely [Cu(DPQ)(Gluc)]·2H₂O (CuGluc, DPQ = pyrazino[2,3-f][1,10]phenanthroline), with good water-solubility and high anticancer activity was synthesized by using D-gluconic acid (Gluc-2H) as an auxiliary ligand. The complex was well characterized by single-crystal X-ray diffraction analysis, elemental analysis, molar conductivity, and Fourier transform infrared spectroscopy (FTIR). The DNA-binding experiments revealed that CuGluc was bound to DNA by intercalation with end-stacking binding. CuGluc could oxidatively cleave DNA, in which ¹O₂ and H₂O₂ were involved. In addition, CuGluc was bound to the IIA subdomain of human serum albumin (HSA) through hydrophobic interaction and hydrogen bonding, showing a good affinity for HSA. The complex showed superior anticancer activity toward several cancer cells than cisplatin in vitro. Further studies indicated that CuGluc caused apoptotic cell death in human liver cancer (HepG2) cells through elevated intracellular reactive oxygen species (ROS) levels, mitochondrial dysfunction, cell cycle arrest, and caspase activation. Interestingly, CuGluc also triggered the ferroptosis mechanism through lipid peroxide accumulation and inhibition of glutathione peroxidase 4 (GPX4) activity. More importantly, CuGluc significantly inhibited tumor growth in vivo, which may benefit from the combined effects of apoptosis and ferroptosis. This work provides a promising strategy to develop highly effective antitumor copper complexes by coordinating with the glucose metabolite D-gluconic acid and exploiting the synergistic effects of apoptosis and ferroptosis mechanisms.

Copper(II) and Cobalt(II) Complexes Based on Abietate Ligands from Pinus Resin: Synthesis, Characterization and Their Antibacterial and Antiviral Activity against SARS-CoV-2

Co-abietate and Cu-abietate complexes were obtained by a low-cost and eco-friendly route. The synthesis process used Pinus elliottii resin and an aqueous solution of CuSO₄/CoSO₄ at a mild temperature (80 °C) without organic solvents. The obtained complexes are functional pigments for commercial architectural paints with antipathogenic activity. The pigments were characterized by Fourier-transform infrared spectroscopy (FTIR), mass spectrometry (MS), thermogravimetry (TG), near-edge X-ray absorption fine structure (NEXAFS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and colorimetric analysis. In addition, the antibacterial efficiency was evaluated using the minimum inhibitory concentration (MIC) test, and the antiviral tests followed an adaptation of the ISO 21702:2019 guideline. Finally, virus inactivation was measured using the RT-PCR protocol using 10% (w/w) of abietate complex in commercial white paint. The Co-abietate and Cu-abietate showed inactivation of >4 log against SARS-CoV-2 and a MIC value of 4.50 µg·mL^-1 against both bacteria Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The results suggest that the obtained Co-abietate and Cu-abietate complexes could be applied as pigments in architectural paints for healthcare centers, homes, and public places.

Synthesis and anticancer mechanisms of zinc(II)-8-hydroxyquinoline complexes with 1,10-phenanthroline ancillary ligands

Twenty new zinc(II) complexes with 8-hydroxyquinoline (H-Q1-H-Q6) in the presence of 1,10-phenanthroline derivatives (D1-D10) were synthesized and formulated as [Zn(Q1)₂(D1)] (DQ1), [Zn(Q2)₂(D2)]·CH₃OH (DQ2), [Zn(Q1)₂(D3)] (DQ3), [Zn(Q1)₂(D4)] (DQ4), [Zn(Q3)₂(D5)] (DQ5), [Zn(Q3)₂(D4)] (DQ6), [Zn(Q4)₂(D5)]·CH₃OH (DQ7), [Zn(Q4)₂(D6)] (DQ8), [Zn(Q4)₂(D3)]·CH₃OH (DQ9), [Zn(Q4)₂(D1)]·H₂O (DQ10), [Zn(Q5)₂(D4)] (DQ11), [Zn(Q6)₂(D6)]·CH₃OH (DQ12), [Zn(Q5)₂(D2)]·5CH₃OH·H₂O (DQ13), [Zn(Q5)₂(D7)]·CH₃OH (DQ14), [Zn(Q5)₂(D8)]·CH₂Cl₂ (DQ15), [Zn(Q5)₂(D9)] (DQ16), [Zn(Q5)₂(D1)] (DQ17), [Zn(Q5)₂(D5)] (DQ18), [Zn(Q5)₂(D10)]·CH₂Cl₂ (DQ19) and [Zn(Q5)₂(D3)] (DQ20). They were characterized using multiple techniques. The cytotoxicity of DQ1-DQ20 was screened using human cisplatin-resistant SK-OV-3/DDP ovarian cancer (SK-OV-3CR) cells and normal hepatocyte (HL-7702) cells. Complex DQ6 showed low IC₅₀ values (2.25 ± 0.13 μM) on SK-OV-3CR cells, more than 3.0-8.0 times more cytotoxic than DQ1-DQ5 and DQ7-DQ20 (≥6.78 μM), and even 22.2 times more cytotoxic than the standard cisplatin, the corresponding free H-Q1-H-Q6 and D1-D10 alone (>50 μM). As a comparison, DQ1-DQ20 displayed nontoxic rates against healthy HL-7702 cells. Furthermore, DQ6 and DQ11 induced significant apoptosis via mitophagy pathways. DQ6 also significantly inhibited tumor growth in an in vivo SK-OV-3-xenograft model (ca. 49.7%). Thus, DQ6 may serve as a lead complex for the discovery of new antitumor agents.

Heteronuclear Ru(II)-Re(I) complexes as potential photodynamic anticancer agents with anti-metastatic and anti-angiogenic activities

Herein, three heterometallic Ru(II)-Re(I) complexes, [Ru(NN)₂(tpphz)Re(CO)₃Cl](PF₆)₂ (N-N = 2,2'-bipyridine (bpy, in RuRe1), 1,10-phenanthroline (phen, in RuRe2), 4,7-diphenyl-1,10-phenanthroline (DIP, in RuRe3), tpphz = tetrapyrido[3,2-a:2',3'-c:3″,2″-h:2″',3″'-j]phenazine), using tpphz as a bridging ligand to connect Ru(II) polypyridyl moiety and Re(I) tricarbonyl moiety were designed and synthesized. Cytotoxicity tests revealed that RuRe1-3 exhibited high phototoxicities against several cancer cell lines tested, with IC₅₀ values ranging from 0.8 to 6.8 μM. Notably, RuRe2 exhibited the most significant increase in cytotoxicity against human prostate cancer (PC3) cells under light (450 nm) irradiation, with phototoxicity index (PI) value increasing by >112.3-fold. Further mechanistic studies of RuRe2 revealed that RuRe2-mediated PDT could induce tumor cell apoptosis through the mitochondrial pathway. Moreover, RuRe2-mediated PDT could inhibit PC3 cell scratch healing and reduce the expression levels of matrix metalloproteinases 2 (MMP-2), matrix metalloproteinases 9 (MMP-9) and vascular endothelial growth factor receptor VEGFR2. Finally, angiogenic activity assays performed in human umbilical vein endothelial cells (HUVECs) showed that RuRe2 exerted an anti-angiogenesis effect. Our study demonstrated that RuRe1-3 were promising PDT antitumor agents with potential anti-metastatic and anti-angiogenic activities.

Antitumor activity of synthetic three copper(II) complexes with terpyridine ligands

Three new synthetic terpyridine copper(II) complexes were characterized. The copper(II) complexes induced apoptosis of three cancer cell lines and arrested T-24 cell cycle in G1 phase. The complexes were accumulated in mitochondria of T-24 cells and caused significant reduction of the mitochondrial membrane potential. The complexes increased both intracellular ROS and Ca²⁺ levels and activated the caspase-3/9 expression. The apoptosis was further confirmed by Western Blotting analysis. Bcl-2 was down-regulated and Bax was upregulated after treatment with complexes 1-3. The in vivo studies showed that complexes 1-3 obviously inhibited the growth of tumor without significant toxicity to other organs.

Synthesis of 3-carene-derived nanocellulose/1,3,4-thiadiazole-amide complexes with antifungal activity for plant protection

BACKGROUND

Nanopesticides have been proved to be a powerful and promising tool to solve the issues in agriculture. The purpose of the present study was to develop ecofriendly nanopesticide systems by the strategy of comprehensive utilization of two natural biomass resources (bagasse and turpentine oil) because of their incomparable advantages.

RESULTS

In this research, a series of nanocellulose carriers ETOCN-1-ETOCN-4 (ETOCN, esterified TEMPO-oxidized cellulose nanofibers) with different degrees of substitution were prepared and characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Then, 21 1,3,4-thiadiazole-amide compounds 8a-8u containing gem-dimethylcyclopropane ring were designed, synthesized and characterized. A preliminary bioassay indicated that compound 8i (R = p-Br Ph) exhibited broad-spectrum antifungal activity against the tested fungi. Furthermore, drug-loading complexes 8i/ETOCN-1-8i/ETOCN-4 were fabricated by integration of nanocellulose-based carriers ETOCN-1-ETOCN-4 with bioactive compound 8i, and the drug-loading capacities, microstructures and sustained-releasing performance of these complexes were also investigated. According to the observation of scanning electron microscopy (SEM) images of complex 8i/ETOCN-2, the small-molecule drug and the carrier formed a well-distributed and compact complex, which led to the excellent drug-loading capacity and sustained-releasing performance in the ethanol/water (1:1, v/v) system.

CONCLUSIONS

Complexes 8i/ETOCN-1-8i/ETOCN-4 deserved further study as the promising candidates for the development of nanopesticides. © 2022 Society of Chemical Industry.

Experimental and Theoretical DFT Study of Cu(I)/N,N-Disubstituted-N'-acylthioureato Anticancer Complexes: Actin Cytoskeleton and Induction of Death by Apoptosis in Triple-Negative Breast Tumor Cells

Six complexes with the general formula [Cu(acylthioureato)(PPh3)2] were synthesized and characterized using spectroscopic techniques (IR, UV/visible, and 1D and 2D NMR), mass spectrometry, elemental analysis, and X-ray diffraction. Interpretation of the in vitro cytotoxicity data of Cu(I) complexes took into account their stability in cell culture medium. DFT calculations showed that NMR properties, such as the shielding of carbon atoms, are affected by relativistic effects, supported by the ZORA Hamiltonian in the theoretical calculations. Additionally, the calculation of the energies of the frontier molecular orbitals predicted that the structural changes of the acylthiourea ligands did not cause marked changes in the reactivity descriptors. All complexes were cytotoxic to the evaluated tumor cell lines [MDA-MB-231 (triple-negative breast cancer, TNBC), MCF-7 (breast cancer), and A549 (lung cancer)]. In the MDA-MB-231 cell line, complex 1 significantly altered the cytoskeleton of the cells, reducing the density and promoting the condensation of F-actin filaments. In addition, the compound caused an increase in the percentage of cells in the fragmented DNA region (sub-G0) and induced cell death via the apoptotic pathway starting at the IC50 concentration. Taken together, the results show that complex 1 has cytotoxic and apoptotic effects on TNBC cells, which is a cell line originating from an aggressive, difficult-to-treat breast cancer.

Investigation of the influence of chirality and halogen atoms on the anticancer activity of enantiopure palladium(ii) complexes derived from chiral amino-alcohol Schiff bases and 2-picolylamine

In order to evaluate the impact of chirality and halogen-substitution pattern on biological activity, four mixed-ligand enantiomeric pairs of Pd(ii) complexes were synthesized and characterized.

Coordination compounds of biogenic metals as cytotoxic agents in cancer therapy

The review summarizes the data on the structures and methods for the synthesis of compounds with anticancer activity based on biogenic metals, which can replace platinum drugs prevailing in cytotoxic therapy. The main focus is given to the comparison of the mechanisms of the cytotoxic action of these complexes, their efficacy and prospects of their use in clinical practice. This is the first systematic review of cytotoxic zinc, iron, cobalt and copper compounds. The structure – activity relationships and the mechanisms of antitumour action are formulated for each type of metal complexes.

The bibliography includes 181 references.

Ligand substituent effect on the cytotoxicity activity of two new copper(ii) complexes bearing 8-hydroxyquinoline derivatives: validated by MTT assay and apoptosis in MCF-7 cancer cell line (human breast cancer)

In this study, we have examined the effect of ligand substituent on the structure-cytotoxicity relationships of the MCF-7 cancer cell line (human breast cancer), by two copper(ii) complexes {[Cu(qmbn)(Hqmba)(q)]·NO3·2H2O} (1) and {[Cu(Hqmba)2(q)]·NO3·2H2O} (2) (where, qmbn = 2-(quinolin-8-yloxy)(methyl) benzonitrile (L1); Hqmba = 2-((quinolin-8-yloxy)methyl)benzoic acid (L2) and q = quinolin-8-olate). The structural analysis reveals that both the complexes exhibit distorted octahedral (CuN3O3) configuration which is further corroborated by density functional theory (DFT) calculations. The cytotoxicity impact of ligands (L1 and L2) and complexes (1 and 2) was screened against the MCF-7 cell line (human breast cancer). The MTT assay uptake indicated that the presence of -COOH functionality in complex 2 leads to higher cytotoxicity (lower IC50) than that observed for complex 1 containing a -CN group. This could be due to the strong H-bonding forming propensity of the carboxylic acids. Incubation of MCF-7 cancer cells with IC50 concentrations of 1 and 2 promoted cellular detachments via nuclear condensation and membrane destabilization followed by apoptosis as a result of metal-assisted generation of reactive oxygen species. Flow cytometry analysis showed that 1 and 2 might prompt early apoptosis in MCF-7 cells as the maximum percentage of cells appeared in the LR quadrant. Furthermore, mRNA expression analysis confirmed that both the complexes induced apoptosis in MCF-7 cells. Comparative mRNA expression analysis of complexes with their respective ligands also confirmed the enhanced apoptotic behavior of complexes. Furthermore, molecular docking studies of the complexes have also been performed with the active site of EGFR kinase receptors (major target for any cancer causing agent) due to similar analogues with FDA-approved EGFR inhibitors in order to rationalize its promising cytotoxicity activity.

Copper(II) and iron(III) complexes of chiral dehydroabietic acid derived from natural rosin: metal effect on structure and cytotoxicity

A novel optically pure dinuclear copper(II) complex of a rosin derivative dehydroabietic acid (DHA, HL) was synthesized and fully characterized. The in vitro antitumor activities of the copper(II) complex Cu2(µ2-O)(L)4(DMF)2 (1) were explored and compared with those of a trinuclear iron(III) complex [Fe3(µ3-O)(L)6(CH3OH)2(CH3O)]·H2O (2). 1 was more cytotoxic than 2, and the in vitro cytotoxicity of 1 was comparable to that of cisplatin and oxaliplatin. The metal coordination improved the cytotoxicity of DHA. 1 could arrest cycle in G1 phase and induce apoptosis in MCF-7 cell. 1 increased reactive oxygen species level, GSSG/GSH ratio, and Ca2+ production, and caused the loss of mitochondrial membrane potential (Δψm) in MCF-7 cells. The up-regulated Bax and down-regulated Bcl-2 expression levels, caspase-9/caspase-3 activation, and the release of Cyt c demonstrate that 1 triggered mitochondria-mediated intrinsic apoptosis in MCF-7 cells. Caspase-8/caspase-4 activation and up-regulated Fas expression indicate that death receptor-mediated extrinsic apoptosis was included. Comet assay and up-regulated γ-H2AX and p53 expressions confirmed that 1 caused DNA damage in MCF-7 cells. Moreover, 1 led to enhancement of the biomarker of lipid peroxidation and the indicator of protein carbonylation in MCF-7 cells. All the results suggest that 1 could kill MCF-7 cells by generating oxidative stress, impairing DNA, promoting lipid peroxidation and protein carbonylation, and inducing apoptosis and autophagy. Furthermore, 1 also displayed antimetastatic activities with inhibition of cell invasion and migration, together with antiangiogenesis properties. On the whole, copper complex based on rosin derivatives is worth developing as metal-based antitumor drugs.

Discovery of novel dehydroabietic acid derivatives as DNA/BSA binding and anticancer agents

To explore the biological properties of rosin derivatives, two dehydroabietic acid derivatives N-(5-dehydroabietyl-1,3,4-thiadiazole)-yl-pyridine-2-carboxamide (DTPC) and di-N-(5-dehydroabietyl-1,3,4-thiadiazole)-yl-pyridine-2,6-carboxamide (DDTPC) with 1,3,4-thiadiazole, pyridine and amide moieties were designed and synthesized according to superposition principle of activity group. They interact with calf thymus DNA (CT DNA) via intercalation based on the results of circular dichroism (CD) and fluorescence spectroscopy, DNA denaturation and viscosity studies. Fluorescence and CD spectral experiments indicate that they might be transported and stored by protein like bovine serum albumin (BSA). MTT assay was further carried out to examine their cytotoxicity, they both showed selective cytotoxicity and DTPC exhibited better cytotoxicity. The antiproliferative effect of DTPC toward A431 cell line was stronger than that of clinically used cisplatin and oxaliplatin. In addition, the cytotoxicity of DTPC and DDTPC was closely related with their DNA binding ability.

Radiosensitivity enhancement by Co-NMS-mediated mitochondrial impairment in glioblastoma

We investigated the radiosensitizing effects of Co-NMS, a derivative of nimesulide based on a cobalt carbonyl complex, on malignant glioma cells. In the zebrafish exposed to Co-NMS ranging from 5 to 20 μM, cell death and heat shock protein 70 expression in the brain and neurobehavioral performance were evaluated. Our data showed that Co-NMS at 5 μM did not cause the appreciable neurotoxicity, and thereby was given as a novel radiation sensitizer in further study. In the U251 cells, Co-NMS combined with irradiation treatment resulted in significant inhibition of cell growth and clonogenic capability as well as remarkable increases of G2/M arrest and apoptotic cell population compared to the irradiation alone treatment. This demonstrated that the Co-NMS administration exerted a strong potential of sensitizing effect on the irradiated cells. With regard to the tumor radiosensitization of Co-NMS, it could be primarily attributed to the Co-NMS-derived mitochondrial impairment, reflected by the loss of mitochondrial membrane potential, the disruption of mitochondrial fusion and fission balance as well as redox homeostasis. Furthermore, the energy metabolism of the U251 cells was obviously suppressed by cotreatment with Co-NMS and irradiation through repressing mitochondrial function. Taken together, our findings suggested that Co-NMS could be a desirable drug to enhance the radiotherapeutic effects in glioblastoma patients.

β-Carboline copper complex as a potential mitochondrial-targeted anticancer chemotherapeutic agent: Favorable attenuation of human breast cancer MCF7 cells via apoptosis

The development of preferentially selective cancer chemotherapeutics is a new trend in drug research. Thus, we designed and synthesized novel ternary complexes, [Cu(tryp)(Hnor)₂(DMSO)]NO₃ (1) and [Zn(tryp)(Hnor)₂(DMSO)]NO₃(2) (tryp = DL-Tryptophane; Hnor = Norharmane, β-carboline; DMSO = Dimethyl sulfoxide), characterized with elemental analysis, FTIR, UV–vis, FL, NMR, ESI-MS, and molar conductivity. Furthermore, the TD-DFT studies with UV–vis and FTIR validated the proposed structures of 1 and 2. Moreover, we evaluated the HOMO-LUMO energy gap and found that 1 has a smaller energy gap than 2. Then, 1 and 2 were assessed for anticancer chemotherapeutic potential against cancer cell lines MCF7 (human breast cancer) and HepG2 (human liver hepatocellular carcinoma) as well as the non-tumorigenic HEK293 (human embryonic kidney) cells. The MTT assay illustrated the preferentially cytotoxic behavior of 1 when compared with that of 2 and cisplatin (standard drug) against MCF7 cells. Moreover, 1 was exposed to MCF7 cells, and the results indicated the arrest of the G2/M phases, which followed the apoptotic pathway predominantly. Generation of ROS, GSH depletion, and elevation in LPO validated the redox changes prompted by 1. These studies establish the great potential of 1 as a candidate for anticancer therapeutics.

Synthesis and antitumor evaluation of (aryl)methyl-amine derivatives of dehydroabietic acid-based B ring-fused-thiazole as potential PI3K/AKT/mTOR signaling pathway inhibitors

In an attempt to search for new natural product-based antitumor agents, a series of novel (aryl)methyl-amine derivatives of dehydroabietic acid-based B ring-fused-thiazole were designed and synthesized. The primary bioassay showed that compounds 5r and 5s presented certain inhibitory activity against cancer cells, weak cytotoxic activity against normal cells, and inhibitory activity against PI3K/AKT/mTOR signaling pathway. The binding modes and the binding site interactions between the active compounds and the target proteins were predicted preliminarily by the molecular docking method.

Synthesis and anticancer evaluation of novel 1H-benzo[d]imidazole derivatives of dehydroabietic acid as PI3Kα inhibitors

Phosphatidylinositol 3-kinase (PI3K) is one of the most attractive therapeutic targets for cancer treatment. In this study, a series of new 2-arylthio- and 2-arylamino-1H-benzo[d]imidazole derivatives of dehydroabietic acid were designed, synthesized and characterized by ¹H NMR, ¹³C NMR, IR and MS spectra analyses. In the in vitro anticancer assay, some title compounds showed significant inhibitory activities against four cancer cell lines (HCT-116, MCF-7, HeLa and HepG2). Among them, compound 9g exhibited the most potent activity with IC₅₀ values of 0.18 ± 0.03, 0.43 ± 0.05, 0.71 ± 0.08 and 0.63 ± 0.09 μM against four cancer cell lines, and considerably lower cytotoxicity to human gastric mucosal cell line Ges-1 (IC₅₀: 21.95 ± 0.73 μM). Besides, compound 9g displayed a certain selective activity to PI3Kα (IC₅₀ = 0.012 ± 0.002 μM) over PI3Kβ, γ and δ, and meanwhile, it can remarkably decrease the expression level of p-Akt (Ser473). In addition, compound 9g could increase intracellular reactive oxygen species level, decrease mitochondrial membrane potential, upregulate Bax and cleaved caspase-3/9 levels, downregulate Bcl-2 level and thus induce the apoptosis of HCT-116 cells in a dose-dependent manner. The results suggested that compound 9g could be considered as a promising PI3Kα inhibitor.

Synthesis and biological evaluation of novel N-(piperazin-1-yl)alkyl-1H-dibenzo[a,c]carbazole derivatives of dehydroabietic acid as potential MEK inhibitors

In this paper, a series of novel 1H-dibenzo[a,c]carbazole derivatives of dehydroabietic acid bearing different N-(piperazin-1-yl)alkyl side chains were designed, synthesised and evaluated for their in vitro anticancer activities against three human hepatocarcinoma cell lines (SMMC-7721, HepG2 and Hep3B). Among them, compound 10g exhibited the most potent activity against three cancer cell lines with IC₅₀ values of 1.39 ± 0.13, 0.51 ± 0.09 and 0.73 ± 0.08 µM, respectively. In the kinase inhibition assay, compound 10g could significantly inhibit MEK1 kinase activity with IC₅₀ of 0.11 ± 0.02 µM, which was confirmed by western blot analysis and molecular docking study. In addition, compound 10g could elevate the intracellular ROS levels, decrease mitochondrial membrane potential, destroy the cell membrane integrity, and finally lead to the oncosis and apoptosis of HepG2 cells. Therefore, compound 10g could be a potent MEK inhibitor and a promising anticancer agent worthy of further investigations.

A simultaneously GSH-depleted bimetallic Cu(ii) complex for enhanced chemodynamic cancer therapy

A bimetallic Cu(ii) complex was developed as a novel antitumor chemodynamic therapy agent with glutathione depletion properties.