The cytotoxic and growth inhibitory effects of palladium(II) complexes on MDA-MB-435 cells

Novel palladium(II) and Zinc(II) Schiff base complexes: Synthesis, biophysical studies, and anticancer activity investigation

BACKGROUND

Schiff base metal complexes are considered promising chemotherapeutic agents due to their potential application in cancer therapy.

METHODS

The current work sought to synthesize a brand-new Schiff base ligand obtained from 2-hydroxybenzohydrazide and (E)- 1-(2-(p-tolyl)hydrazono)propan-2-one with metal ions which included Pd(II) and Zn(II) ions. Elemental analyses, FT-IR, mass spectra, 1H NMR, UV-Vis spectrometer, and computational analysis characterized the compound's structure. In vitro, the breast cancer cell line (MCF-7) was tested for its sensitivity to Schiff base (HL) and its Pd(II) and Zn(II) complexes. The half-maximal inhibitory concentration IC₅₀ of the compounds was determined and used to perform the comet assay, which was carried out to reveal the photo-induced DNA damaging ability of the compounds of individual cells. Moreover, the compounds' effects on antioxidant defense systems of enzymes in cells: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities and oxidant Malondialdehyde (MDA) were examined in MCF-7 cells.

RESULTS

The Pd(II) complex displayed approximately the same IC₅₀ as Cisplatin, while Zn(II) complex had better activity than Cisplatin with very low IC₅₀, 1.40 μg/ml. Significant alterations in SOD, CAT, GPx, and MDA production were discovered, inducing oxidative stress, enlarging ROS production, and reducing the antioxidant amount. This change was approximately similar in most compounds. Consequently, it promoted apoptosis, particularly the Zn(II) complex, which demonstrated an improved impact because of its ability to influence the antioxidant defense systems of enzymes, mostly SOD and GPx, besides increasing MDA levels.

CONCLUSION

It can be concluded that Zn(II) complex is the most effective anticancer drug since it induced a very similar genotoxic effect as Cisplatin and has a very low IC₅₀ value.

Cytotoxicity Induced by Newly Synthesized Palladium (II) Complexes Lead to the Death of MCF-7 and MDA-MB-435 Cancer Cell Lines

Purpose: Breast cancer is the most common female malignancy and melanoma is the most lethal type of skin cancer. Traditional therapy for cancer treatment is far from satisfactory due to drug resistance and side effects, thus a search for new medicines is being emphasized. Palladium(II) complexes have been reported as anticancer potential agents. In this work, the anticancer activities and cell death induction of a new series of square-planar Pd(II) complexes were evaluated against MCF-7 and MDA-MB-435 cancer cells. Methods: MCF-7 (breast carcinoma) and MDA-MB-435 (melanoma) cells were cultivated, and treated with ligand and Pd(II) complexes. Cell growth, migration and adhesion inhibition, morphological alterations, cell death induction and, DNA interaction upon treatment were studied. Results: Pd(II) complexes exhibited both short and long-term antiproliferative effects on both cell lines, reducing by 80% cell growth in the SRB assay and abolishing longterm proliferation, estimated by the clonogenic assay. Complexes reduced significantly (P<0.05) cell migration and adhesion when compared to the control group. Complexes induced morphological alterations in cell lines and significant (P<0.05) cellular shrinkage. Cell death was induced and the complexes were able to interact with DNA, inducing cleavage of double-stranded DNA, which may account for the complexes cytotoxic effects, observed against both MCF-7 and MDA-MB-435 cells. Conclusion: Overall, the complexes exhibited cytotoxic activities and induced cell death. These observations emphasize an anticancer role with a potential therapeutic value for Pd(II) complexes to improve the outcome of patients with breast cancer and melanoma.

Biological properties of metal complexes of curcumin

Curcumin, a naturally occurring phenolic compound isolated from Curcuma longa, has different pharmacological effects, including antiinflammatory, antimicrobial, antioxidant, and anticancer properties. However, curcumin has been found to have a limited bioavailability because of its hydrophobic nature, low-intestinal absorption, and rapid metabolism. Therefore, there is a need for enhancing the bioavailability and its solubility in water in order to increase the pharmacological effects of this bioactive compound. One strategy is curcumin complexation with transition metals to circumvent the abovementioned problems. Curcumin can undergo chelation with various metal ions to form metallo-complexes of curcumin, which may show greater effects as compared with curcumin alone. Promising results with metal curcumin complexes have been observed with regard to antioxidant, anticancer, and antimicrobial activity, as well as in treatment of Alzheimer's disease. The present review provides a concise summary of the characterization and biological properties of curcumin-metal complexes. © 2019 BioFactors, 45(3):304-317, 2019.

Anticancer activity of palladium-based complexes against triple-negative breast cancer

Treatment of triple-negative breast carcinoma (TNBC) remains an unmet medical need with no targeted therapy available to date. Accounting for 10-30% of all human breast cancer tumors, this mammary carcinoma subtype has a particularly poor prognosis owing to its high metastatic potential, aggressive biology and limited pharmacological treatment options. Platinum chemotherapeutics are the mainstay therapy in patients with TNBC but their clinical use is limited by severe toxicity and acquired resistance. Palladium-based complexes are appealing alternative metal-based drugs because of significant similarities regarding structure and coordination chemistry with the platinum agents. This review summarizes the knowledge gathered so far on 121 Pd(II) complexes, emphasizing their anticancer activity and putative pharmacological targets toward TNBC.

Stryphnodendron adstringens ("Barbatimão") Leaf Fraction: Chemical Characterization, Antioxidant Activity, and Cytotoxicity Towards Human Breast Cancer Cell Lines

We evaluated the chemical composition, antioxidant activity, and antitumor potential of a fraction that was isolated from Stryphnodendron adstringens (barbatimão) leaf aqueous extract. Fraction is composed by gallic acid, procyanidin dimer B1, and (-)-epicatechin-3-O-gallate and it exhibits antioxidant and cytotoxic activities. Fraction was cytotoxic against two human breast cancer cell lines, ER (+) and MCF-7 and the triple-negative, MDA-MB-435. The sulforhodamine B assay showed that, as compared to normal control cells, the fraction significantly (P < 0.05) decreased cancer cell viability. The morphological alterations noted in the treated cancer cells were cell rounding-up, shrinkage, and nuclear condensation reduction of cell diameter and length. Treatment with fraction increased cancer cell expression of Bax, caspase-9, active caspase-3, caspase-8, LC-3, and beclin-1 and decreased Bcl-2, caspase-3, and pro-caspase-8 expression. Altogether, fraction is cytotoxic to both breast cancer cell lines, induces cell death, and its mechanism of action seems to include the induction of apoptosis. Our data support a positive role of the fraction as a chemopreventive agent for antineoplastic drug development.

Anti-cancer palladium complexes: a focus on PdX2L2, palladacycles and related complexes

Much success has been achieved with platinum-based chemotherapeutic agents, i.e. through interactions with DNA. The long-term application of Pt complexes is thwarted by issues, leading scientists to examine other metals such as palladium which could exhibit complementary modes of action (given emphasis wherever known). Over the last 10 years several research groups have focused on the application of an eclectic array of palladium complexes (of the type PdX2L2, palladacycles and related structures) as potential anti-cancer agents. This review therefore provides readers with an up to date account of the advances that have taken place over the past several decades.

Procyanidin b2 cytotoxicity to mcf-7 human breast adenocarcinoma cells

Procyanidins have attracted some attention due to their demonstrated chemopreventive action, a relatively new and promising strategy to prevent cancer. Breast cancer is one of the leading causes of death in women worldwide and its treatment needs improvements. The aim of this work was to verify the procyanidin dimmer B2 cytotoxic effect to MCF-7 human breast cancer cells. MCF-7 cells were cultured in RPMI medium, containing 20% fetal bovine serum and antibiotics in a CO₂ chamber. The cells were treated with different concentrations of B2 and its cytotoxic potential was assessed by the sulforhodamine B assay, morphologically through haematoxylin-eosin staining and by DNA fragmentation analysis. The significance of differences between experimental conditions was determined using the ANOVA test, followed by the Tukey test when P<0.05. Cell proliferation decreased in a concentration and time-dependent manner upon procyanidin dimmer B2 treatment, being 19.20 μM the IC₅₀. Procyanidin dimmer B2 treatment displayed concentration and time-dependent decline in MCF-7 cells compared to control and also induced morphological alterations compatible with cell-death induction. Cell condensation and cell diameter decreased (3.5 folds compared to control cells), after 48 h cell-exposure to 50 μM procyanidin dimmer B2, but the DNA ladder formation was not observed. In conclusion, our results demonstrated that procyanidin dimmer B2 exhibits cytotoxic activity to MCF-7 cells and it could be a potential antineoplastic agent. Further studies are necessary to clarify the procyanidin dimmer B2 mechanism of action. The evaluation of biological efficacy of individual components is an important step towards drug discovery and development.