Palladium(II) complexes with R2edda-derived ligands. Part II. Synthesis, characterization and in vitro antitumoral studies of R2eddip esters and palladium(II) complexes

Biotin-Avidin System-Based Delivery Enhances the Therapeutic Performance of MSC-Derived Exosomes

Exosomes (EXs) shed by mesenchymal stem cells (MSCs) are potent therapeutic agents that promote wound healing and regeneration, but when used alone in vivo, their therapeutic potency is diminished by rapid clearance and bioactivity loss. Inspired by the biotin-avidin interaction, we developed a simple yet versatile method for the immobilization of MSC-derived EXs (MSC-EXs) into hydrogels and achieved sustained release for regenerative purposes. First, biotin-modified gelatin methacryloyl (Bio-GelMA) was fabricated by grafting NHS-PEG₁₂-biotin onto the amino groups of GelMA. Biotin-modified MSC-EXs (Bio-EXs) were then synthesized using an in situ self-assembling biotinylation strategy, which provided sufficient binding sites for MSC-EX delivery with little effect on their cargo composition. Thereafter, Bio-EXs were immobilized in Bio-GelMA via streptavidin to generate Bio-GelMA@Bio-EX hydrogels. An in vitro analysis demonstrated that Bio-EXs could be taken up by macrophages and exerted immunomodulatory effects similar to those of MSC-EXs, and Bio-GelMA@Bio-EX hydrogels provided sustained release of MSC-EXs for 7 days. After subcutaneous transplantation, a more constant retention of MSC-EXs in Bio-GelMA@Bio-EX hydrogels was observed for up to 28 days. When placed in an artificial periodontal multitissue defect, the functionalized hydrogels exhibited an optimized therapeutic performance to regrow complex periodontal tissues, including acellular cementum, periodontal ligaments (PDLs), and alveolar bone. In this context, Bio-GelMA@Bio-EX hydrogels exerted a robust immunomodulatory effect that promoted macrophage polarization toward an M2 phenotype. Our findings demonstrate that MSC-EXs delivered with the aid of the biotin-avidin system exhibit robust macrophage-modulating and repair-promoting functions and suggest a universal approach for the development of MSC-EX-functionalized biomaterials for advanced therapies.

Current Development of Metal Complexes with Diamine Ligands as Potential Anticancer Agents

Background::

The discovery of cisplatin and the subsequent research revealed the importance of dinitrogen-containing moiety for the anticancer action of metal complexes. Moreover, certain diamine ligands alone display cytotoxicity that contributes to the overall activity of corresponding complexes.

Objective::

To summarize the current knowledge on the anticancer efficacy, selectivity, and the mechanisms of action of metal complexes with various types of diamine ligands.

Method::

The contribution of aliphatic acyclic, aliphatic cyclic, and aromatic diamine ligands to the anticancer activity and selectivity/toxicity of metal complexes with different metal ions were analyzed by comparison with organic ligand alone and/or conventional platinum-based chemotherapeutics.

Results::

The aliphatic acyclic diamine ligands are present mostly in complexes with platinum. Aliphatic cyclic diamines are part of Pt(II), Ru(II) and Au(III) complexes, while aromatic diamine ligands are found in Pt(II), Ru(II), Pd(II) and Ir(III) complexes. The type and oxidation state of metal ions greatly influences the cytotoxicity of metal complexes with aliphatic acyclic diamine ligands. Lipophilicity of organic ligands, dependent on alkyl-side chain length and structure, determines their cellular uptake, with edda and eddp/eddip ligands being most useful in this regard. Aliphatic cyclic diamine ligands improved the activity/toxicity ratio of oxaliplatin-type complexes. The complexes with aromatic diamine ligands remain unexplored regarding their anticancer mechanism. The investigated complexes mainly caused apoptotic or necrotic cell death.

Conclusion::

Metal complexes with diamine ligands are promising candidates for efficient and more selective alternatives to conventional platinum-based chemotherapeutics. Further research is required to reveal the chemico-physical properties and molecular mechanisms underlying their biological activity.

In vitro antitumor activity, metal uptake and reactivity with ascorbic acid and BSA of some gold(III) complexes with N,N'-ethylenediamine bidentate ester ligands

Four novel gold(III) complexes of general formulae [AuCl₂{(S,S)-R₂eddl}]PF₆ (R₂eddl=O,O'-dialkyl-(S,S)-ethylenediamine-N,N'-di-2-(4-methyl)pentanoate, R=n-Pr, n-Bu, n-Pe, i-Bu; 1-4, respectively), were synthesized and characterized by elemental analysis, UV/Vis, IR, and NMR spectroscopy, as well as high resolution mass spectrometry. Density functional theory calculations pointed out that (R,R)-N,N'-configuration diastereoisomers were energetically the most favorable. Duo to high cytotoxic activity complex 3 was chosen for stability study in DMSO, no decomposition occurs within 24h, and for the reaction with ascorbic acid in which was reduced immediately. Additionally, 3 interacts with bovine serum albumin (BSA) as proven by UV/Vis spectroscopy. In vitro antitumor activity was determined against human cervix adenocarcinoma (HeLa), human myelogenous leukemia (K562), and human melanoma (Fem-x) cancer cell lines, as well as against non-cancerous human embryonic lung fibroblast cells MRC-5. The highest activity was observed against K562 cells (IC₅₀: 5.04-6.51μM). Selectivity indices showed that these complexes are less toxic than cisplatin. 3 had a similar viability kinetics on HeLa cells as cisplatin. Drug accumulation studies in HeLa cells showed that the total gold uptake increased much faster than that of cisplatin pointing out that 3 more efficiently enters the cells than cisplatin. Furthermore, morphological and cell cycle analysis reveal that gold(III) complexes induced apoptosis in time- and dose-dependent manner.

Improved in vitro antitumor potential of (O,O'-Diisobutyl-ethylenediamine-N,N'-di-3-propionate)tetrachloridoplatinum(IV) complex under normoxic and hypoxic conditions

(O,O'-Diisobutyl-ethylenediamine-N,N'-di-3-propionate)tetrachloridoplatinum(IV), [PtCl4(iBu2eddp)], shows an improved pharmacological profile in comparison to cisplatin. This is manifested through accelerated dying process led by necrotic cell death, reflected through mitochondrial collapse, strong ATP depletion and reactive oxygen species production. Loss of mitochondrial potential was further followed with intensive apoptosis that finalized with DNA fragmentation. Different dynamic of tumoricidal action could be partly ascribed to less affected repair mechanisms in comparison to cisplatin. Importantly, [PtCl4(iBu2eddp)] did not induce necrosis in primary fibroblasts suggesting different intracellular response of normal vs. tumor cells. This selectivity toward malignant phenotype is further confirmed by retained tumoricidal potential in hypoxic conditions, while cisplatin became completely inefficient.

In vitro anticancer activity of gold(III) complexes with some esters of (S,S)-ethylenediamine-N,N'-di-2-propanoic acid

Five novel gold(III) complexes of general formulas [AuCl2{(S,S)-R2eddip}]PF6, ((S,S)-eddip = (S,S)-ethylenediamine-N,N'-di-2-propanoate, R = n-Bu, n-Pe, i-Bu, i-Am, cPe; 1-5, respectively) were synthesized and characterized by UV/Vis, IR and NMR spectroscopy and mass spectrometry. DFT calculations indicated that (R,R)-N,N'-configuration diastereoisomers were the most stable for 1-5. 3 is stable in DMSO for at least 24 h, but immediate hydrolysis in PBS occurs. 3 is readily reduced with ascorbic acid and forms adducts with bovine serum albumin (BSA). In vitro anticancer activity of the gold(III) complexes against human cervix adenocarcinoma HeLa, human myelogenous leukemia K562, human melanoma Fem-x tumor cell lines, as well as against non-cancerous human embryonic lung fibroblast cell line MRC-5 was determined using MTT assay. Complex 4 showed highest activity and selectivity (IC50(Fem-x) = 1.3 ± 0.2; IC50(MRC-5)/IC50(Fem-x) = 72.5 ± 12.4), 4 times more active and 28 times more selective than cisplatin. Complexes induced apoptotic mode of death in a time-dependent manner in HeLa cells.

Synthesis and Antitumor and Surface Activity of Novel Tetrachloro Metallate Complexes of Sulfaquinoxaline with Co(II), Cu(II), or Sn(II) Chlorides

New sulfonamide tetrachloro metallate complexes that might possess strong carbonic anhydrase (CA) inhibitory properties were synthesized by the reaction of 4-amino-N-(quinoxalin-2-yl) benzene sulfonamide (sulfaquinoxaline) hydrochloride with different metal chlorides, i.e. CoCl2, CuCl2 or SnCl2. The produced metal complexes of the sulfonamide derivative, containing divalent cations, were characterized by standard procedures. These metal complexes might possess topical antiglaucoma properties which might make them more effective as pharmacological agents. The synthesized complexes exhibited significant cytotoxic activity against colon HCT-116 human cell line. Surface properties of these surfactants were investigated. The surface properties studies included critical micelle concentration (CMC), maximum surface excess (Γmax), minimum surface area (Amin). Free energy of micellization (ΔG°mic) and adsorption (ΔG°ads) were calculated.

Platinum and Palladium Polyamine Complexes as Anticancer Agents: The Structural Factor

Since the introduction of cisplatin to oncology in 1978, Pt(II) and Pd(II) compounds have been intensively studied with a view to develop the improved anticancer agents. Polynuclear polyamine complexes, in particular, have attracted special attention, since they were found to yield DNA adducts not available to conventional drugs (through long-distance intra- and interstrand cross-links) and to often circumvent acquired cisplatin resistance. Moreover, the cytotoxic potency of these polyamine-bridged chelates is strictly regulated by their structural characteristics, which renders this series of compounds worth investigating and their synthesis being carefully tailored in order to develop third-generation drugs coupling an increased spectrum of activity to a lower toxicity. The present paper addresses the latest developments in the design of novel antitumor agents based on platinum and palladium, particularly polynuclear chelates with variable length aliphatic polyamines as bridging ligands, highlighting the close relationship between their structural preferences and cytotoxic ability. In particular, studies by vibrational spectroscopy techniques are emphasised, allowing to elucidate the structure-activity relationships (SARs) ruling anticancer activity.

Cytotoxicity and effects of 1,10-phenanthroline and 5-amino-1,10-phenanthroline derivatives on some immunocompetent cells

The biological activity of previously synthesized compounds [(phen)(3)(H(+))(2)(NO(3)(-))(2) (1), Pd(5-NH(2)-phen)(2)(NO(3))(2) (2) and Pd(phen)(2)(NO(3))(2)(H(2)O) (3)] was investigated in vivo. The three compounds did not show any histological alterations in the observed lung, liver, spleen and lymph nodes of White Wistar rats. The propidium iodine staining did not discover any cytotoxic effect of the tested derivatives. The tests for immunological response predominantly showed stimulation of the antibody-producing B-cells and lower or no stimulation of the T-cells. The LIF-test showed better stimulation of all lymphocytes with 1, followed by 2 and 3. Substance 3 showed highest stimulating effect on B-cell blood lymphocytes in all doses (maximum in the lowest dose), whereas the impact of 2 is weaker and that of 1 is the weakest. The T-cell immune response after treatment with substance 1 is best influenced by dose of 1mg in the spleen cell-fraction, followed by 3 (5 mg).