Palladium (II) complex and thalidomide intercept angiogenic signaling via targeting FAK/Src and Erk/Akt/PLCγ dependent autophagy pathways in human umbilical vein endothelial cells.

The current study assessed the effects of the thalidomide and palladium (II) saccharinate complex of terpyridine on the suppression of angiogenesis-mediated cell proliferation. The viability was assessed after treatment with palladium (II) complex (1.56-100 µM) and thalidomide (0.1-400 µM) alone by using ATP assay for 48 h. Palladium (II) complex was found to inhibit growth statistically significant in a dose-dependent manner in HUVECs and promoted PARP-1 cleavage through the production of ROS. On the other hand, thalidomide did not cause any significant change in cell viability. Moreover, cell death was observed to be manifested as late apoptosis due to Annexin V/SYTOX staining after palladium (II) complex treatment however, thalidomide did not demonstrate similar results. Thalidomide and palladium (II) complex also suppressed HUVEC migration and capillary-like structure tube formation in vitro in a time-dependent manner. Palladium (II) complex (5 mg/ml) treatment showed a strong antiangiogenic effect similar to positive control thalidomide (5 mg/ml) and successfully disrupted the vasculature and reduced the thickness of the vessels compared to control (agar). Furthermore, suppression of autophagy enhanced the cell death and anti-angiogenic effect of thalidomide and palladium (II) complex. We also showed that being treated with thalidomide and palladium (II) complex inhibited phosphorylation of the signaling regulators downstream of the VEGFR2. These results provide evidence for the regulation of endothelial cell functions that are relevant to angiogenesis through the suppression of the FAK/Src/Akt/ERK1/2 signaling pathway. Our results also indicate that PLC-γ1 phosphorylation leads to activation of p-Akt and p-Erk1/2 which cause stimulation on cell proliferation at lower doses. Hence, we demonstrated that palladium (II) and thalidomide can induce cell death via the Erk/Akt/PLCγ signaling pathway and that this pathway might be a novel mechanism.

Preparation and Characterization of Palladium Derivate-Loaded Micelle Formulation in Vitro as an Innovative Therapy Option against Non-Small Cell Lung Cancer Cells.

Nanoparticles have been used in cancer treatments to target tumor and reduce side effects. In this study, we aimed to increase the effectiveness of palladium(II) complex [PdCl(terpy)](sac) ⋅ 2H2 O, which previously showed anticancer potential, by preparing the nanoparticle formulation. An inhalable micellar dispersion containing a palladium(II) complex (PdNP) was prepared and its physicochemical characteristics were evaluated using in vitro tests. Morphology, size and surface charges of particle and loading/encapsulation efficiency of PdNP were analyzed by scanning electron microscopy, zeta sizer and inductively coupled plasma mass spectrometry while aerosol properties of PdNP were measured by the next generation impactor. A549 and H1299 non-small lung cancer cell types were used for cytotoxicity using SRB and ATP assays. Fluorescent staining and M30 antigen assay were carried out for cell death evaluation. Apoptosis was confirmed by flow cytometry analyses. SEM, particle size, and zeta potential results showed the particles have inhalable properties. The amount of the palladium(II) complex loaded into the particles was quantified which indicated high encapsulation efficiencies (97 %). The micellar dispersion expected to reach the alveolar region and the brachial region was determined 35 % and 47 %, respectively. PdNP showed an anti-growth effect by increasing reactive oxygen species that is followed by the induction of mitochondria-dependent apoptosis that is evidenced by pyknotic nuclei and M30 antigen level increments and disruption of polarization of membrane in mitochondria (Δψm). The results show that PdNP might be a promising inhalable novel complex to be used in non-small cell lung cancer, which warrants animal studies in further.

Cytotoxic platinum(II) complexes derived from saccharinate and phosphine ligands: synthesis, structures, DNA cleavage, and oxidative stress-induced apoptosis.

A series of the structurally related platinum(II) saccharinate (sac) complexes with alkylphenylphosphines, namely cis-[Pt(sac)2(PPh2Me)2]·DMSO (1), cis-[Pt(sac)2(PPhMe2)2] (2), cis-[Pt(sac)2(PPh2Et)2] (3), and cis-[Pt(sac)2(PPhEt2)2]·2DMSO (4), were synthesized and fully characterized; their structures were determined by X-ray crystallography. All the complexes were investigated for their anticancer potentials on three human cancer cells including A549 (lung), MCF-7 (breast), and HCT116 (colon) in addition to a noncancerous human bronchial epithelial cells (BEAS-2B). Specifically, 1 and 3 showed significant cytotoxic effects against MCF-7 and HCT116 cell lines in comparison to cisplatin, and were considered as the most potent ones in the series. The cytotoxic complexes were found to cleave DNA efficiently. In addition, the binding interactions of the complexes with DNA were confirmed by enzyme inhibition and molecular docking studies. Complexes 1 and 3 were capable of inducing apoptosis and arrested the cell cycle at the DNA synthesis (S) phase in MCF-7 cells. Furthermore, 1 and 3 caused the excessive generation of reactive oxygen species (ROS), leading to mitochondrial dysfunction and double-strand DNA breaks.

Trans-Pd/Pt(II) saccharinate complexes with a phosphine ligand: Synthesis, cytotoxicity and structure-activity relationship.

New trans-[Pd(sac)2(PPhMe2)(DMSO)]·H2O (Pd) and trans-[Pt(sac)2(PPhMe2)2]·H2O (Pt) complexes (sac = saccharinate and PPhMe2 = dimethylphenylphosphine) were synthesized and characterized by elemental analysis, IR, NMR, ESI-MS spectral analyses and X-ray diffraction. The complexes were evaluated for their in vitro cytotoxicity against breast (MCF-7), colon (HCT116) and lung (A549) human cancer cell lines. The ATP viability assay displayed that Pd was biologically inactive, but Pt showed significant anticancer potency on MCF-7 cancer cells, similar to cisplatin. The results suggested that Pt targeted DNA, whereas Pd displayed higher binding affinity towards human serum albumin (HSA). Mechanism of action studies of Pt suggested apoptotic cell death due to significant increase in intracellular ROS (reactive oxygen species) levels, mitochondrial damage and formation of DNA double-strand breaks. Finally, this work represents a new example of potent transplatin anticancer complexes.

Anti-angiogenic effect of a Palladium(II)-Saccharinate Complex of Terpyridine in vitro and in vivo.

Anti-angiogenic activity of palladium (Pd)(II)-based complexes is unknown despite their quite powerful anticancer activity. This study was therefore carried out to evaluate both in vivo anti-angiogenic effect and in vitro cytotoxic activity of a Pd(II)-based complex. ([Pd(sac)(terpy)](sac)·4H2O(sac=saccharinate and terpy=2,2':6',2″-terpyridine)) on HUVEC cells. The anti-angiogenic activity of the complex was evaluated in vivo using the chick embryo chorioallantoic membrane (CAM) assay, tube formation assay and the cytotoxicity was screened using the MTT viability assays. The CAM treated with the complex (50µg/pellet) showed a strikingly high anti-angiogenic effect (score 1.1±0.2) compared to the positive controls cortisone, prednisone and (±)-thalidomide (e.g. (±)-thalidomide score 0.9±0.2) tested at the same concentration. Furthermore, the complex showed neither membrane toxicity nor irritation at the tested concentration. According to the MTT assays, the human umbilical vein endothelial cell (HUVEC) viability was inhibited in a dose-dependent manner at tested concentrations (1.56-100µM). Pd(II) complex also reduced the tube network at the lower dose than the compared with thalidomide. These results suggest that the Pd(II)-complex has strong anti-angiogenic activity, which adds an important feature to the previously-described anticancer activity of the complex.

A palladium(II)-saccharinate complex of terpyridine exerts higher anticancer potency and less toxicity than cisplatin in a mouse allograft model.

The main aim of this study is to assess the safety and antitumor efficacy of a palladium(II) (Pd)-saccharinate complex with terpyridine. To characterize the Pd(II) complex in vitro, its cytotoxicity was evaluated using a water-soluble tetrazolium salt cell viability assay and the mechanism of cell death was assessed by DNA fragmentation/condensation and live cell imaging analyses. The antitumor efficacy and safety of the Pd(II) complex in-vivo were examined by analyzing reduction in tumor size, changes in body and organ weight, histopathological analysis of liver, kidney, and tumor sections, and biochemical analysis of serum in C57BL/6 mice. Our results showed that the Pd(II) complex was more cytotoxic to cancer cells than noncancer cell lines and caused cell death through apoptotic pathways. The treatment of the Pd(II) complex in tumor-bearing mice effectively reduced the tumor size at half the dose used for cisplatin. The Pd(II) complex appeared to exert less liver damage than the cisplatin-based complex on changes in the hepatic enzymes levels in the serum. Hence, the complex appears to be a potential chemotherapeutic drug with high antitumor efficacy and fewer hepatotoxic complications, providing an avenue for further studies.

Cytotoxic and apoptotic effects of the combination of palladium (II) 5,5-diethylbarbiturate complex with bis(2-pyridylmethyl)amine and curcumin on non small lung cancer cell lines.

Metal-based chemotherapeutics such as cisplatin are widely used treatment of lung cancer which is the major cause of cancer-related mortality worldwide. Recent studies demonstrated that novel metal-based compounds have strong cytotoxic activity in a similar way as cisplatin. Therefore, metal-based compounds have been synthesized and investigated in order to determine their cytotoxic activities. It has been also reported curcumin, which has been derived from turmeric plant, has powerful cytotoxic effect on various cancer cell lines. In the light of these data, it has been investigated the cytotoxic effects of combination of curcumin (0.78-100µM) and palladium (II) 5,5-diethylbarbiturate complex with bis(2-pyridylmethyl)amine [Pd(II) complex] (0.39-50µM) against non small lung cancer cell lines, A549 and H1299. It has been found that combination of Pd(II) complex and curcumin enhanced the cytotoxic activity and apoptotic cell death at 48h, compared to single use of each agent, only in H1299 cell line (combination index <1). Apoptosis was evident by annexin v staining positivity, increased caspase 3/7 activity and the presence of pyknotic nuclei. Pro-apoptotic genes of TNFRSF10A and HRK were found to be involved in apoptotic cell death. In conclusion, the application of this combination may be regarded as a novel and effective approach for the treatment of lung cancer due to its promising cytotoxic and apoptotic effect.

The role of cell cycle progression for the apoptosis of cancer cells induced by palladium(II)-saccharinate complexes of terpyridine.

OBJECTIVES: Palladium complexes are potent and less toxic molecules in comparison to other metal based agents. Here, we characterized two palladium(II) saccharinate complexes with terpyridine for their cell cycle specificity. MATERIALS AND METHODS: Cells were arrested at G1, G1/S boundary or mitosis using mimosine, double-Thymidine block, aphidicolin, nocodazole or colcemid, and evaluated based on morphology and flow cytometry. Synchronized cells were treated with the Pd(II) complexes, and viability was measured via MTT assay. RESULTS: While treatment of arrested cells with the Pd(II) complexes resulted in no significant change in cell death in HCT-116 and MDA-MB-231 cells, HeLa cells were more sensitive in S/G1. The main form of cell death was found to be apoptosis. CONCLUSIONS: Pd(II) complexes appear to be cell-cycle non-specific, while cell line dependent differences may be observed. Cells die through apoptosis regardless of the cell cycle stage, which makes these complexes more promising as anti-cancer agents.

Synthesis, Spectroscopic, Structural and Quantum Chemical Studies of a New Imine Oxime and Its Palladium(II) Complex: Hydrolysis Mechanism.

In this work, we report synthesis, crystallographic, spectroscopic and quantum chemical studies of a new imine oxime, namely (4-nitro-phenyl)-(1-phenyl-ethylimino)-acetaldehyde oxime (nppeieoH). Spectroscopic and X-ray diffraction studies showed that nppeieoH is hydrolyzed in aqueous solution, forming nitroisonitrosoacetophenone (ninap) and the hydrolysis product binds to Pd(II) to yield [Pd(nppeieo)(ninap)]. The mechanism of the hydrolysis reaction has been theoretically investigated in detail, using density functional theory (DFT) with the B3LYP method. The vibrational and the electronic spectra of nppeieoH and its Pd(II) complex, the HOMO and LUMO analysis, Mulliken atomic charges and molecular electrostatic potential were also performed. The predicted nonlinear optical properties of both compounds are higher than those of urea.

Cytotoxic activity of novel palladium-based compounds on leukemia cell lines.

Effective treatment methods for human leukemia are under development, but so far none of them have been found to be completely satisfactory. It was recently reported that palladium complexes have significant anticancer activity as well as lower toxicity compared with some clinically used chemotherapeutics. The anticancer activities of two novel palladium(II) complexes, [Pd(sac)(terpy)](sac)·4H2O and [PdCl(terpy)](sac)·2H2O, were tested against three human leukemia cell lines, Jurkat, MOLT-4, and THP-1, in comparison with cisplatin and adriamycin. The cytotoxic effect of the drugs was determined using the MTT assay. Cell death was assessed using fluorescein isothiocyanate-annexin/propidium iodide staining for flow cytometry. Furthermore, p53 phosphorylation, poly(ADP-ribose) polymerase cleavage, and Bax and Bcl-2 mRNA levels were examined to elucidate the mechanism of cell death induction. Both complexes exhibited a significant dose-dependent antigrowth effect in vitro. The complexes predominately induced apoptosis, but necrosis was also observed. In-vitro results have shown that palladium(II) complexes may be regarded as potential anticancer agents for treating human leukemia. Therefore, further analysis to determine the putative mechanism of action and in-vivo studies on animal models are warranted.

Addition of niclosamide to palladium(II) saccharinate complex of terpyridine results in enhanced cytotoxic activity inducing apoptosis on cancer stem cells of breast cancer.

Wnt signaling is one of the core signaling pathways of cancer stem cells (CSCs). It is re-activated in CSCs and plays essential role in the survival, self-renewal and proliferation of these cells. Therefore, we aimed to evaluate the cytotoxic effects of palladium(II) complex which is formulated as [PdCl(terpy)](sac)2H2O and its combination with niclosamide which is an inhibitor of Wnt signaling pathway associated with breast cancer stem cells. Characteristic cell surface markers (CD44(+)/CD24(-)) were determined by flow cytometry in CSCs. ATP viability assay was used to determine the cytotoxic activity. The mode of cell death was evaluated morphologically using fluorescence microscopy and biochemically using M30 ELISA assay as well as performing qPCR. Our study demonstrated that the combination of niclosamide (1.5 µM) and Pd(II) complex (12.5, 25 and 50 µM) at 48 h has enhanced cytotoxic activity resulted from the induction of apoptosis (indicated by the presence of pyknotic nuclei, increments in M30 and over expression of proapoptotic genes of TNFRSF10A and FAS). Importantly, the addition of niclosamide resulted in the suppression of autophagy (proved by the decrease in ATG5 gene levels) that might have contributed to the enhanced cytotoxicity. In conclusion, the application of this combination may be regarded as a novel and effective approach for the treatment of breast cancer due to its promising cytotoxic effect on cancer stem cells that cause recurrence of the disease.

Anti-growth effect of a novel trans-dichloridobis[2-(2-hydroxyethyl)pyridine]platinum (II) complex via induction of apoptosis on breast cancer cell lines.

Breast cancer still continues to be the leading cause of cancer-related mortality in women worldwide. Although advances have been made in the treatment of this disease during the past decade, new approaches and novel compounds are urgently needed. The aim of this study was to evaluate the cytotoxic activity of trans-[PtCl2(2-hepy)2] [2-hepy=2-(2-hydroxyethyl) pyridine] on breast cancer cell lines, MCF-7 and MDA-MB-231. The platinum (II) complex was synthesized and characterized by our laboratory working group. Anti-growth effect was assayed by the MTT and ATP viability assays and also monitored real-time using xCELLigence system. The mode of cell death was evaluated by using the fluorescence microscopy (Hoechst 33342+Calcein-AM+Propidium iodide staining), Western blotting (cleaved PARP and caspase 3, total caspase 8), flow cytometry (quantitative analysis of live, early/late apoptotic, dead cells and caspase 3/7 activity) and the RT-PCR (the genes analyzed were BCL-2L10, BIK, BAX, BCL-2, FASLG, HRK, TNFRSF10B, and TNFRSF10A). The platinum (II) complex had anti-growth effect in a dose dependent manner in vitro. Cells were killed by apoptosis as evidenced by the pyknotic nuclei, cleavage of poly-(ADP-ribose) polymerase (PARP) and induction of active caspase-3. These results suggest that the complex might represent a potentially active novel drug for the breast cancer treatment and warrants further studies due to its promising cytotoxic activity.

Biochemical and proteomic analysis of a potential anticancer agent: Palladium(II) Saccharinate complex of terpyridine acting through double strand break formation.

Metal based chemotherapeutic drugs are widely used as an effective method to defeat various cancers. In this study, the mechanism of action of a novel therapeutic agent, [Pd(sac)(terpy)](sac)·4H2O (sac = saccharinate, and terpy = 2,2':6',2″-terpyridine) was studied. To better understand the proteomic changes in response to this agent, we performed nano LC-MS/MS analyses in human breast cancer cells (MDA-MB-231). Thirty proteins were identified to be differentially expressed more than 40% after drug treatment. Many cellular pathways were affected, including proteins involved in DNA repair, apoptosis, energy metabolism, protein folding, cytoskeleton, pre-mRNA maturation, or protein translation. The changes in protein expression were further verified for XRCC5, which plays a role in double strand break (DSB) repair, and ubiquitin, which is involved in protein degradation and apoptosis. The elevated XRCC5 levels were suggestive of increased DSBs. The presence of DSBs was confirmed by smearing of plasmid DNA in vitro and induction of γH2AX foci in vivo. There was also increased intracellular reactive oxygen species (ROS) formation, as detected by 2',7'-dichlorofluorescein diacetate (DCFDA) staining. Scavenging ROS by N-acetylcysteine rescued cell death in response to Pd(II) treatment, potentially explaining how the Pd(II) complex damaged the DNA. The details of this analysis and the significance will be discussed during the scope of this work.

Di- and polynuclear silver(I) saccharinate complexes of tertiary diphosphane ligands: synthesis, structures, in vitro DNA binding, and antibacterial and anticancer properties.

A series of new silver(I) saccharinate (sac) complexes, [Ag2(sac)2(µ-dppm)H2O]·H2O (1), {[Ag2(µ-sac)2(µ-dppe)]·3H2O·CH2Cl2} n (2), [Ag2(µ-sac)2(µ-dppp)] n (3), and [Ag(sac)(µ-dppb)] n (4) [dppm is 1,1-bis(diphenylphosphino)methane, dppe is 1,2-bis(diphenylphosphino)ethane, dppp is 1,3-bis(diphenylphosphino)propane, and dppb is 1,4-bis(diphenylphosphino)butane], have been synthesized and characterized by C, H, N elemental analysis, IR spectroscopy, (1)H NMR, (13)C NMR, and (31)P NMR spectroscopy, electrospray ionization mass spectrometry, and thermogravimetry-differential thermal analysis. Single-crystal X-ray studies show that the diphosphanes act as bridging ligands to yield a dinuclear complex (1) and one-dimensional coordination polymers (2 and 4), whereas the sac ligand adopts a µ2-N/O bridging mode in 2, and is N-coordinated in 1 and 4. The interaction of the silver(I) complexes with fish sperm DNA was investigated using UV-vis spectroscopy, fluorescence spectroscopy, and agarose gel electrophoresis. The binding studies indicate that the silver(I) complexes can interact with fish sperm DNA through intercalation, and complexes 1 and 3 have the highest binding affinity. The gel electrophoresis assay further confirms the binding of the complexes with the pBR322 plasmid DNA. The minimum inhibitory concentrations of the complexes indicate that complex 1 exhibits very high antibacterial activity against standard bacterial strains of Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus, being much higher than those of AgNO3, silver sulfadiazine, ciprofloxacin, and gentamicin. Moreover, complexes 1-3 exhibit very high cytotoxic activity against A549 and MCF-7 cancer cell lines, compared with AgNO3 and cisplatin. The bacterial and cell growth inhibitions of the silver(I) complexes are closely related to their DNA binding affinities.

Evaluation of the molecular mechanisms of a palladium(II) saccharinate complex with terpyridine as an anticancer agent.

Metal-based compounds represent promising anticancer therapeutic agents. In this study, the mechanism of action of a novel metal-based drug, a palladium(II) (Pd) complex ([PdCl(terpy)](sac)·2H2O, terpy=2,2':6',2''-terpyridine and sac=saccharinate), was elucidated. The tested compound induced cytotoxicity in nine different human cancer cell lines that originated from various organs, suggesting a broad spectrum of activity. The IC50 values were significantly higher for noncancerous cells when compared with cancer cells. We found that cells treated with the Pd(II) complex exhibited increased caspase 3/7 activities and condensed/fragmented nuclei, as demonstrated by nuclear staining and DNA laddering. Morphological features, such as cellular shrinkage and blebbing, were also observed, indicating that apoptosis was the primary mechanism of cell death. Pd(II) treatment induced DNA double-stranded breaks both in vitro and in vivo, potentially accounting for the source of stress in these cells. Although caspase 3/7 activities were elevated after Pd(II) treatment, silencing or using inhibitors of caspase 3 did not block apoptosis. Other molecules that could potentially play a role in Pd(II)-induced apoptosis, such as p53 and Bax, were also tested using silencing technology. However, none of these proteins were essential for cell death, indicating either that these molecules do not participate in Pd(II)-induced apoptosis or that other pathways were activated in their absence. Hence, this new molecule might represent a promising anticancer agent that exhibits cytotoxicity in p53-mutant, Bax-mutant, and/or caspase 3-mutant cancer cells.

Apoptosis-inducing effect of a palladium(II) saccharinate complex of terpyridine on human breast cancer cells in vitro and in vivo.

The anti-growth effect of a palladium(II) complex-[PdCl(terpy)](sac)·2H2O] (sac=saccharinate, and terpy=2,2':6',2″-terpyridine)-was tested against human breast cancer cell lines, MCF-7 and MDA-MB-231. Anti-growth effect was assayed by the MTT and ATP viability assays in vitro and then confirmed on Balb/c mice in vivo. The mode of cell death was determined by both histological and biochemical methods. The Pd(II) complex had anti-growth effect on a dose dependent manner in vitro and in vivo. The cells died by apoptosis as evidenced by the pyknotic nucleus, cleavage of poly-(ADP-ribose) polymerase (PARP) and induction of active caspase-3. These results suggest that the palladium(II) saccharinate complex of terpyridine represents a potentially active novel complex for the breast cancer treatment, thus warrants further studies.

Synthesis, crystal structures, DNA binding and cytotoxicity of two novel platinum(II) complexes containing 2-(hydroxymethyl)pyridine and pyridine-2-carboxylate ligands.

Two new platinum(II) complexes, trans-[Pt(2-mpy)(2)]·4H(2)O (1) and [PtCl(2-pyc)(2-hmpy)]·H(2)O (2), where 2-hmpy=2-(hydroxymethyl)pyridine, 2-mpy=deprotonated 2-hmpy and 2-pyc=pyridine-2-carboxylate, have been synthesized and characterized by elemental analysis, IR, NMR, and X-ray crystallography. The DNA binding affinities of these complexes for Fish Sperm DNA (FS-DNA) were investigated using fluorescence, viscosity, thermal denaturation and gel electrophoresis measurements. Fluorescence analysis indicates that complex 1 binds to DNA by a single intercalative mechanism, while complex 2 exhibits two types of interactions such as intercalation and covalent binding. Gel electrophoresis assay demonstrates ability of the complexes to cleavage the supercoiled pBR322 plasmid DNA. The in vitro cytotoxicities of both complexes were preliminarily evaluated and the cytotoxicity of complex 1 against the human lung cancer cells (H1299) is similar to oxaliplatin, but higher than transplatin and carboplatin.

Palladium(II) saccharinate complexes with bis(2-pyridylmethyl)amine induce cell death by apoptosis in human breast cancer cells in vitro.

The outcomes of breast cancer patients are still poor although new compounds have recently been introduced into the clinic. Therefore, novel chemical approaches are required. In the present study, palladium(II) and corresponding platinum(II) complexes containing bis(2-pyridylmethyl)amine (bpma) and saccharine were synthesized and tested against human breast cancer cell lines, MCF-7 and MDA-MB-231, in vitro. Cytotoxicity was first screened by the MTT assay and the results were further confirmed by the ATP assay. The palladium complexes 1 and 3 yielded stronger cytotoxicity than the corresponding platinum complexes 2 and 4 at the same doses. The palladium complex 3 was found to be the most cytotoxic one. Therefore, a more comprehensive study was carried out with this complex only. The mode of cell death was determined morphologically under fluorescent microscope and biochemically with detection of active caspase-3 and PARP cleavage by Western blot. Changes in apoptosis-related gene expressions were measured with qPCR. It was demonstrated that complex 3 caused cell death by apoptosis determined by fluorescence imaging and Western blot. As a sign of apoptosis, PARP was cleaved in both of the cell lines. In addition, caspase-3 was cleaved in MDA-MB-231 cells while this cleavage was not observed in MCF-7. The results show that the complex 3 is a promising anti-cancer compound against breast cancer with an IC50 value of 3.9 µM for MCF-7 and 4.2 µM for MDA-MB-231 cells, which warrants further animal experiments.

Synthesis, structural characterization and cell death-inducing effect of novel palladium(II) and platinum(II) saccharinate complexes with 2-(hydroxymethyl)pyridine and 2-(2-hydroxyethyl)pyridine on cancer cells in vitro.

Four palladium(II) and platinum(II) saccharinate (sac) complexes with 2-(hydroxymethyl)pyridine (2-hmpy) and 2-(2-hydroxyethyl)pyridine (2-hepy), namely trans-[Pd(2-hmpy)2(sac)2]·H2O (1), trans-[Pt(2-hmpy)2(sac)2]·3H2O (2), trans-[Pd(2-hepy)2(sac)2] (3) and trans-[Pt(2-hepy)2(sac)2] (4), have been synthesized and characterized by elemental analysis, UV-vis, IR and NMR. Single crystal X-ray analysis reveals that the metal(II) ions in each complex are coordinated by two sac and two 2-hmpy or 2-hepy ligands with a trans arrangement. Anticancer effects of 1-4 were tested against four different cancer cell lines (A549 and PC3 for lung cancer, C6 for glioblastoma, and Hep3B for liver cancer). Cytotoxicity was first screened by the MTT assay and the results were further confirmed by the ATP assay. The mode of cell death was determined by both histological and biochemical methods. Among the metal complexes, complex 2 resulted in relatively stronger anti-growth effect in a dose-dependent manner (3.13-200µM), compared to the others, by inducing apoptosis.

Promising anti-growth effects of palladium(II) saccharinate complex of terpyridine by inducing apoptosis on transformed fibroblasts in vitro.

Fibrosarcoma is one of the fatal cancer types and there is still not satisfactory success in its treatment despite new drugs. Therefore, the search for a new compound has been going on. It is currently known that some palladium-based anti-cancer compounds seem to have powerful apoptosis-inducing effects in cancer cells. For this purpose, a palladium(II)-saccharinate complex containing terpyridine which was synthesized by our research group was investigated in terms of its anti-tumor effects against mouse embryonic fibroblast NIH/3T3 (normal cell line) and rat embryonic fibroblast 5RP7 (H-ras transformed cell line) in vitro. The MTT and ATP viability assays were used to determine anti-growth/cytotoxic effects. Cytotoxic activity was confirmed by real time cytotoxicity analysis system. Flow cytometry analysis was further used to determine the mode of cell death (apoptosis/necrosis). Apoptosis was confirmed by triple-staining the cells with Hoechst 33342/PI/Calcein-AM triple and evaluated with fluorescence microscopy. It was found that the compound showed significant anti-growth activity by inducing apoptosis in a dose dependent manner. In conclusion, taking into account the cytotoxic activity of the compound at even relatively lower doses, in vivo experiments to elucidate its potential use for the treatment of fibrosarcoma are warranted.