Silver(I) Bromide Phosphines Induce Mitochondrial-Mediated Apoptosis in Malignant Human Colorectal Cells.

Due to its emerging resistance to current therapies, colon cancer remains one of the most difficult types of cancer to treat. Silver, a non-invasive metal, is well-known for its antimicrobial and anti-cancer properties. Two novel silver(I) phosphine complexes, [silver(I) diphenyl-2-pyridylphosphine]Br (1) and [silver(I) is 4-(dimethylamino)phenyldiphenylphosphine]Br (2), were synthesized and characterized by elemental analysis, infrared spectroscopy, and nuclear magnetic resonance (1H, 13C, 31P). To assess the complexes' potentials as antiproliferative agents, experiments were conducted on human colorectal cancer cells (HT-29) in vitro. The evaluation involved the analysis of morphological changes, the performance of an alamarBlue® proliferation assay, and the undertaking of flow cytometric analyses to detect mitochondrial alterations. Complex 1 displayed superior selectivity and significant inhibitory effects on malignant HT-29 cells while exhibiting minimal toxicity towards two non-malignant HEK-293 and MRHF cells. Moreover, after 24 h of treatment, complex 1 (IC50, 7.49 µM) demonstrated higher efficacy in inhibiting cell proliferation compared with complex 2 (IC50, 21.75 µM) and CDDP (IC50, 200.96 µM). Flow cytometric studies indicated that complex 1 induced regulated cell death, likely through mitochondrial-mediated apoptosis. Treatment with complex 1 induced morphological changes indicative of apoptosis, which includes membrane blebbing, PS externalization, increased levels of reactive oxygen species (ROS) and mitochondrial membrane depolarization (ΔΨm). These observations suggest that complex 1 targets the mitochondria and holds promise as a novel metal-based anti-cancer therapeutic for the selective treatment of colorectal cancer.

Synthesis and anti-cancer activity of bis-amino-phosphine ligand and its ruthenium(II) complexes.

The development of both chemotherapeutic drug resistance as well as adverse side effects suggest that the current chemotherapeutic drugs remain ineffective in treating the various types of cancers. The development of new metallodrugs presenting anti-cancer activity is therefore needed. Ruthenium complexes have gained a great deal of interest due to their promising anti-tumour properties and reduced toxicity in vivo. This study highlighted the effective induction of cell death in a malignant melanoma cell by two novel bis-amino-phosphine ruthenium(II) complexes referred to as GA105 and GA113. The IC50 concentrations were determined for both the complexes, the ligand and cisplatin, for comparison. Both complexes GA105 and GA113 displayed a high anti-cancer selectivity profile as they exhibited low IC50 values of 6.72 µM and 8.76 µM respectively, with low toxicity towards a non-malignant human cell line. The IC50 values obtained for both complexes were lower than that of cisplatin. The new complexes were more effective compared to the free ligand, GA103 (IC50 = >20 µM). Morphological studies on treated cells induced apoptotic features, which with further studies could indicate an intrinsic cell death pathway. Additionally, flow cytometric analysis revealed that the mode of cell death of complex GA113 was apoptosis. The outcomes herein give further insight into the potential use of selected Ru(II) complexes as alternative chemotherapeutic drugs in the future.

The ability of silver(I) thiocyanate 4-methoxyphenyl phosphine to induce apoptotic cell death in esophageal cancer cells is correlated to mitochondrial perturbations.

First generation silver(I) phosphines have garnered much interest due to their vast structural diversity and promising anticancer activity. Increasing incidences of cancer, side-effects to chemotherapeutic agents and redevelopment of tumors due to resistance prompts the exploration of alternative compounds showing anticancer activity. This study revealed the effective induction of cell death by a silver(I) thiocyanate 4-methoxyphenyl phosphine complex in a malignant esophageal cell line. Apoptotic cell death was confirmed in treated cells. Moreover, mitochondrial targeting via the intrinsic cell death pathway was evident due to low levels of ATP, altered ROS activity, mitochondrial membrane depolarization, cytochrome c release and caspase-9 cleavage. The complex displayed low cytotoxicity towards two human non-malignant, skin and kidney, cell lines. The findings reported herein give further insight into the selective targeting of silver(I) phosphines and support our belief that this complex shows great promise as an effective chemotherapeutic drug.

A Comparison of the Toxicity of Mono, Bis, Tris and Tetrakis Phosphino Silver Complexes on SNO Esophageal Cancer Cells.

BACKGROUND: A broad range of metal-coordinated complexes have been studied for their anticancer activities. However, some of these complexes display high toxicity profiles to non-malignant cells, therefore limiting their use in cancer therapeutics. Aims/Method: Several silver(I) triphenylphosphine adducts were prepared as 1:1 to 1:4 ratios of silver nitrate to triphenylphosphine. They were further used to determine their anticancer activity in a malignant SNO esophageal cell line. The silver(I) phosphine adducts include: [Ag(PPh3)]NO3 (1); [Ag(PPh3)2]NO3 (2); [Ag(PPh3)3]NO3 (3) and [Ag(PPh3)4]NO3 (4). In addition, the activity of complexes 1-4 was compared to previously reported complexes [Ag(Ph2P(CH2)2PPh2)2]NO3 (5) and [Ag(Ph2P(CH2)3PPh2)2]NO3 (6). The cytotoxicity of complexes 1-6 was also evaluated in non-malignant human dermal fibroblast cells (HDF-a). RESULTS: The majority of the complexes (specifically those containing PPh3) were found to be highly toxic to the SNO cells and less toxic towards HDF-a cells, as determined by the alamarBlue® assay. Morphological studies and flow cytometry confirmed that the silver(I) complexes induced apoptosis in the malignant cells. CONCLUSION: These results may have an impact on research related to drug discovery and silver(I) phosphine complexes could be added to the arsenal of anticancer agents in addition to the silver-bis-diphenylphosphinoethane and silver-bis-diphenylphosphinopropane adducts.

Apoptosis-inducing ability of silver(I) cyanide-phosphines useful for anti-cancer studies.

Metal-based drugs have shown early promise as anticancer agents suggesting the potential application of silver(I) complexes as apoptosis-inducing agents. The ability of a silver(I) cyanide containing phosphine complex to induce cell death was evaluated in both a malignant (SNO esophageal cancer) and non-malignant (HDF-a skin and HEK293 kidney) cell lines. A dose-dependent decrease in cell viability was observed in the SNO cells. Light microscopy revealed morphological features indicative of apoptotic cell death. The mode of cell death was confirmed as apoptosis by phosphatidylserine externalization, DNA fragmentation and nuclear condensation. Furthermore, both the non-malignant cell lines showed morphological features indicative of apoptosis when exposed to complex 1. We propose the use of this silver(I) cyanide phosphine complex as an highly effective positive apoptosis control for use in anticancer studies of phosphine complexes.