Design, synthesis and biological evaluation of naphthalenebenzimidizole platinum (II) complexes as potential antitumor agents

A review on metal complexes and its anti-cancer activities: Recent updates from in vivo studies

Research into cancer therapeutics has uncovered various potential medications based on metal-containing scaffolds after the discovery and clinical applications of cisplatin as an anti-cancer agent. This has resulted in many metallodrugs that can be put into medical applications. These metallodrugs have a wider variety of functions and mechanisms of action than pure organic molecules. Although platinum-based medicines are very efficient anti-cancer agents, they are often accompanied by significant side effects and toxicity and are limited by resistance. Some of the most studied and developed alternatives to platinum-based anti-cancer medications include metallodrugs based on ruthenium, gold, copper, iridium, and osmium, which showed effectiveness against many cancer cell lines. These metal-based medicines represent an exciting new category of potential cancer treatments and sparked a renewed interest in the search for effective anti-cancer therapies. Despite the widespread development of metal complexes touted as powerful and promising in vitro anti-cancer therapeutics, only a small percentage of these compounds have shown their worth in vivo models. Metallodrugs, which are more effective and less toxic than platinum-based drugs and can treat drug-resistant cancer cells, are the focus of this review. Here, we highlighted some of the most recently developed Pt, Ru, Au, Cu, Ir, and Os complexes that have shown significant in vivo antitumor properties between 2017 and 2023.

Discovery of 4-(N-dithiobenzyl piperazine)-1,8-naphthalimide as a potent multi-target antitumor agent with good efficacy, limited toxicity, and low resistance

A series of 4-(N-dithiobenzyl piperazine)-1,8-naphthalimide derivatives 4-6 were designed, synthesized, and evaluated as novel multi-target antitumor agents. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) results showed that compounds 5j, 5k, and 6j exhibited superior in vitro antiproliferative activity in MGC-803, HepG-2, SKOV-3, and T24 cancer cell lines and the cisplatin-resistant cell line A549/DDP. HepG-2, SKOV-3, and T24 xenograft assay results revealed that compounds 5j, 5k, and 6j exhibited good antitumor effects compared with amonafide. The pathology results indicated that compound 5j exhibited the least comprehensive toxicity among the three compounds, identifying compound 5j as a good candidate antitumor agent with good efficacy, limited toxicity, and low resistance. Compound 5j was thus chose for further antitumor mechanism investigation. Results from the omics research, confocal immunofluorescence, Western blot, transmission electron microscopy, and flow cytometry indicated that compound 5j exerted antitumor effects through multiple mechanisms, including ferroptosis, autophagy, apoptosis, and cell cycle arrest. These results suggest that screening novel 1,8-naphthalimide-based antitumor agents for good efficacy, limited toxicity, and low resistance based on a multi-target drug strategy is feasible.

Preparation of a Pt(II)-3-Hydroxy-2-tolyl-4H-chromen-4-one Complex Having Antimicrobial, Anticancerous, and Radical Scavenging Activities with Related Computational Studies

A novel benzopyran-based platinum (II)-3-hydroxy-2-tolyl-4H-chromen-4-one (HToC) complex has been prepared and studied by UV-visible spectrophotometry. The study is based on the colored complexation between Pt(II) and HToC in the pH range of 8.92-9.21, resulting in the formation of a stable binary yellow complex exhibiting λmax at 509-525 nm. The formed complex maintains linearity between 0.0 and 1.8 μg Pt(II) mL-1. The well-known qualitative analytical methods, including Job's method of continuous variations and the mole ratio approach, have both proven that the stoichiometry of the complex is 1:2 [Pt(II)/HToC]. Hence, the analytical results suggest that the formed platinum complex exhibits a square planar geometry. The values of various attributes corresponding to spectrophotometric studies and statistical calculations, such as the molar extinction coefficient (6.790 × 104 L mol-1 cm-1), Sandell's sensitivity (0.0029 μg Pt(II) cm-2), standard deviation (± 0.0011), RSD (0.317%), limit of detection (0.0147 μg mL-1) and correlation coefficient (0.9999), show that the performed study satisfies all of the criteria for good sensitivity, versatility, and cost-effectiveness. In order to have an apprehension of the molecular geometry and other structural specifics of the complex, DFT studies have been carried out. The in vitro anticancer potential of the ligand and its platinum complex in the human breast cancer cell line (T-27D), as determined by the MTT assay, reveals that the complex has better antiproliferative potential than the ligand. The antimicrobial potential of the complex has been successfully tested against both Gram-positive and -negative bacteria. Antioxidant capacity results suggest the better radical scavenging capacity of the complex than that of the ligand.

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.

Design, synthesis, and antitumor evaluation of morpholine substituted bisnaphthalimides as DNA targeting agents

A series of mono- and bisnaphthalimides derivatives containing 3-nitro and 4-morpholine moieties were designed, synthesized, and evaluated for their in vitro anticancer activities against four cancer cell lines. Some compounds exhibited relatively good antiproliferative activity on the cell lines tested, in comparison with mitonafide and amonafide. It is noteworthy that bisnaphthalimide A6 was identified as the most potent compound in anti-proliferation against MGC-803 cells, with an IC₅₀ lowered to 0.09 μM, a far greater potency than that of mono-naphthalimide A7, mitonafide, and amonafide. A gel electrophoresis assay revealed that DNA and Topo I were the potential targets of compounds A6 and A7. The treatment of CNE-2 cells with compounds A6 and A7 resulted in an S phase cell cycle arrest, accompanied by the upregulation of the expression levels of the antioncogene p27 and the down-regulation of the expression levels of CDK2 and cyclin E. In addition, compounds A6 and A7-induced apoptosis was further confirmed by flow cytometry, ROS generation assay, and Hoechst 33,258 staining. In particular, in vivo antitumor assay results revealed that bisnaphthalimide A6 exhibited potent anticancer efficiency in an MGC-803 xenograft tumor model, in comparison with mitonafide, and had lower toxicity than mono-naphthalimide A7. In brief, the results suggested that bisnaphthalimide derivatives containing 3-nitro and 4-morpholine moieties might serve as DNA binding agents for the development of new antitumor agents.

Synthesis, isolation and characterisation of fluorinated-benzimidazoisoquinoline regioisomers

A pair of novel fluorinated-benzimidazoisoquinoline regioisomers was synthesised and isolated. Initial structural characterisation and identification employed 1D proton, 1D carbon, correlated spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), and heteronuclear multiple bond correlation (HMBC) nuclear magnetic resonance spectroscopy and mass spectrometry. However, the fluorinated regioisomers could not be differentiated using nuclear magnetic resonance (NMR) alone. Density functional theory calculations and single-crystal X-ray diffraction experiments were used to completely characterise and identify the compounds.

Design, synthesis and antitumor evaluation of new 1,8-naphthalimide derivatives targeting nuclear DNA

Four series of new 3-nitro naphthalimides derivatives, 4(4a‒4f), 5(5a‒5i), 6(6a‒6e) and 7 (7a‒7j), were designed and synthesized as antitumor agents. Methyl thiazolyl tetrazolium (MTT) screening assay results revealed that some compounds displayed effective in vitro antiproliferative activity on SMMC-7721, T24, SKOV-3, A549 and MGC-803 cancer cell lines in comparison with 5-fluorouracil (5-FU), mitonafide and amonafide. Nude mouse xenotransplantation model assay results indicated that compounds 6b and 7b exhibited good in vivo antiproliferative activity in MGC-803 xenografts in comparison with amonafide and cisplatin, suggesting that compounds 6b and 7b could be good candidates for antitumor agents. Gel electrophoresis assay indicated that DNA and Topo I were the potential targets of compounds 6b and 7b, and comet assay confirmed that compounds 6b and 7b could induce DNA damage, while the further study showed that the 6b- and 7b-induced DNA damage was accompanied by the upregulation of p-ATM, P-Chk2, Cdc25A and p-H2AX. Cell cycle arrest studies demonstrated that compounds 6b and 7b arrested the cell cycle at the S phase, accompanied by the upregulation of the expression levels of the antioncogene p21 and the down-regulation of the expression levels of cyclin E. Apoptosis assays indicated that compounds 6b and 7b caused the apoptosis of tumor cells along with the upregulation of the expression of Bax, caspase-3, caspase-9 and PARP and the downregulation of Bcl-2. These mechanistic studies suggested that compounds 6b and 7b exerted their antitumor activity by targeting to DNA, thereby inducing DNA damage and Topo I inhibition, and consequently causing S stage arrest and the induction of apoptosis.

Antimicrobial activity of mono- and polynuclear platinum and palladium complexes

Introduction. Infectious diseases remain a serious threat to humanity worldwide as bacterial pathogens grow more diverse. Bacteria, fungi, and parasites develop resistance to clinically approved antimicrobials, which reduces the efficacy of available drugs and treatment measures. As a result, there is an ever growing demand for new highly effective pharmaceuticals. This review describes mono- and polynuclear platinum and palladium complexes with antimicrobial properties. We compared several groups of antibacterial agents: antibiotics, antioxidant biologically active substances, antimicrobial nanoparticles, nanocomposite materials, biopolymers, micellar systems, and plant extracts. Study objects and methods. The review covered relevant articles published in Web of Science, Scopus, and Russian Science Citation Index for the last decade. The list of descriptors included such terms as mononuclear and binuclear complexes of platinum, palladium, and antimicrobial activity. Results and discussion. Chelates of platinum, palladium, silver, iridium, rhodium, ruthenium, cobalt, and nickel are popular therapeutic agents. Their antimicrobial activity against pathogenic microorganisms can be enhanced by increasing their bioavailability. Metalbased drugs facilitate the transport of organic ligands towards the bacterial cell. The nature of the ligand and its coordination change the thermodynamic stability, kinetic lability, and lipophilic properties of the complex, as well as the reactivity of the central atom. Polynuclear platinum and palladium complexes contain two or more bound metal (coordinate) centers. Covalent bonding with bacterial DNA enables them to form a type of DNA adducts, which is completely different from that of mononuclear complexes. Conclusion. Metal-based drugs with functional monodentate ligands exhibit a greater antimicrobial effect compared to free ligands. Poly- and heteronuclear complexes can increase the number of active centers that block the action of bacterial cells. When combined with other antibacterial agents, they provide a synergistic effect, which makes them a promising subject of further research.

Design, synthesis and biological evaluation of 3-nitro-1,8-naphthalimides as potential antitumor agents

A series of 3-nitro-naphthalimides 1(1a-1h) were designed and synthesized as antitumor agents. MTT assay results showed that all these compounds exhibited obvious antiproliferative activity against SKOV3, HepG2, A549, T-24 and SMMC-7721 cancer cell lines, while compound 1a displayed the best antiproliferative activity against HepG2 and T-24 cell lines in comparison with mitonafide, with IC₅₀ of 9.2 ± 1.8 and 4.133 ± 0.9 μM, respectively. In vivo antiproliferative activity assay results showed that compound 1a exhibited good antiproliferative activity in the HepG2 and T-24 models, compared with mitonafide. Action mechanism results showed that compound 1a could induced the damage of DNA and the inhibition topo I, accompanying by inducing the G2-stage arresting and the apoptosis of T-24 cancer cells through up-regulating expression levels of cyclin B1, cdc 2-pTy, Wee1, γH2AX, p21, Bax and cytochrome c and down-regulating expression of Bcl-2.