Phenotypic Discovery of Thiocarbohydrazone with Anticancer Properties and Catalytic Inhibition of Human DNA Topoisomerase IIα.

Phenotypic screening of α-substituted thiocarbohydrazones revealed promising activity of 1,5-bis(salicylidene)thiocarbohydrazide against leukemia and breast cancer cells. Supplementary cell-based studies indicated an impairment of DNA replication via the ROS-independent pathway. The structural similarity of α-substituted thiocarbohydrazone to previously published thiosemicarbazone catalytic inhibitors targeting the ATP-binding site of human DNA topoisomerase IIα prompted us to investigate the inhibition activity on this target. Thiocarbohydrazone acted as a catalytic inhibitor and did not intercalate the DNA molecule, which validated their engagement with this cancer target. A comprehensive computational assessment of molecular recognition for a selected thiosemicarbazone and thiocarbohydrazone provided useful information for further optimization of this discovered lead compound for chemotherapeutic anticancer drug discovery.

Pd(II) complexes with N-heteroaromatic hydrazone ligands: Anticancer activity, in silico and experimental target identification.

Anticancer activity of Pd complexes 1-5 with bidentate N-heteroaromatic hydrazone ligands was investigated on human acute monocytic leukemia (THP-1; cells in a suspension) and human mammary adenocarcinoma (MCF-7; two-dimensional layer and three-dimensional spheroid tumor model) cell lines. For the Pd(II) complexes with condensation products of ethyl hydrazainoacetate and quinoline-8-carboxaldehyde (complex 1) and 2-formylpyridine (complex 3), for which apoptosis was determined as a mechanism of anticancer activity, further investigation revealed that they arrest the cell cycle in G0/G1 phase, induce generation of reactive oxygen species and inhibit Topoisomerase I in vitro. In silico studies corroborate experimental findings that these complexes show topoisomerase inhibition activity in the micromolar range and indicate binding to a DNA's minor groove as another potential target. Based on the results obtained by circular dichroism and fluorescence spectroscopy measurements, the most active complexes are suitable to be delivered to a blood stream via human serum albumin.

A novel binuclear hydrazone-based Cd(II) complex is a strong pro-apoptotic inducer with significant activity against 2D and 3D pancreatic cancer stem cells.

A novel binuclear Cd complex (1) with hydrazone-based ligand was prepared and characterized by spectroscopy and single crystal X-ray diffraction techniques. Complex 1 reveals a strong pro-apoptotic activity in both human, mammary adenocarcinoma cells (MCF-7) and pancreatic AsPC-1 cancer stem cells (CSCs). While apoptosis undergoes mostly caspase-independent, 1 stimulates the activation of intrinsic pathway with noteworthy down regulation of caspase-8 activity in respect to non-treated controls. Distribution of cells over mitotic division indicates that 1 caused DNA damage in both cell lines, which is confirmed in DNA interaction studies. Compared to 1, cisplatin (CDDP) does not achieve cell death in 2D cultured AsPC-1 cells, while induces different pattern of cell cycle changes and caspase activation in 2D cultured MCF-7 cells, implying that these two compounds do not share similar mechanism of action. Additionally, 1 acts as a powerful inducer of mitochondrial superoxide production with dissipated trans-membrane potential in the majority of the treated cells already after 6 h of incubation. On 3D tumors, 1 displays a superior activity against CSC model, and at 100 µM induces disintegration of spheroids within 2 days of incubation. Fluorescence spectroscopy, along with molecular docking show that compound 1 binds to the minor groove of DNA. Compound 1 binds to the human serum albumin (HSA) showing that the HSA can effectively transport and store 1 in the human body. Thus, our current study strongly supports further investigations on antitumor activity of 1 as a drug candidate for the treatment of highly resistant pancreatic cancer.

(Chalcogen)semicarbazones and their cobalt complexes differentiate HL-60 myeloid leukaemia cells and are cytotoxic towards tumor cell lines.

Cobalt complexes with semi- and thiosemicarbazones of 8-quinolinecarboxaldehyde have been synthesized and characterized by X-ray diffraction analysis. These novel complexes and a previously synthesized cobalt complex with a selenium-based selenosemicarbazone ligand showed myeloid differentiation activity on all trans retinoic acid resistant HL-60 acute myeloid leukaemia cells. They also showed varying levels of cytotoxicity on five human tumor cell lines: cervix carcinoma cells (HeLa), lung adenocarcinoma cells (A549), colorectal adenocarcinoma cells (LS-174), breast carcinoma cells (MDA-MB-361), and chronic myeloid leukaemia (K562) as well as one normal human cell line: fetal lung fibroblast cells (MRC-5). Leukaemia differentiation was most strongly induced by a metal-free oxygen ligand and the selenium ligand, whilst the latter and the cobalt(ii) complex with an oxygen ligand showed the strongest dose-dependent cytotoxic activity. In four out of five investigated tumor cell lines, it was of the same order of magnitude as cisplatin. These best compounds, however, had lower toxicity on non-transformed MRC-5 cells than cisplatin.

Activity of dexrazoxane and amifostine against late cardiotoxicity induced by the combination of doxorubicin and cyclophosphamide in vivo.

Cardiotoxicity is one of the main limiting side effects of doxorubicin and cyclophosphamide (DC) treatment, and this study was organized to identify cardioprotective activity of amifostine and dexrazoxane against DC combination. BalbC/NIH mice underwent DC treatment (DC group), were pre-treated with amifostine (ADC group) or dexrazoxane (IDC group) and were killed at 1.5 and 3 months after treatments when the grade of myocardial damage was analysed by light microscopy using the Billingham scoring method. DC treatment induced severe myocardial damage with one lethal event before evaluation at 3 months. Main characteristics of DC cardiotoxicity were polymorphic myocyte degeneration and alterations in blood vessels followed by ecchymoses, haemorrhage and thromboses. Polymorphism was also found in the IDC and ADC groups, but its morphological patterns were different. In animals subject to IDC treatment, the blood vessels were better preserved than in the ADC group, whereas thrombosis was not seen in either of these two groups. Quantitatively, grade of myocardial injury in the ADC and IDC groups was significantly higher compared with the non-treated group at both times of estimation and significantly lower compared with the DC group at 1.5 months. At 3 months, significance against DC treatment was lost in the ADC group, while preserved in the IDC-treated animals. Also, there was significant progression in the ADC group comparing scores between 1.5 and 3 months. These results revealed that the cardiotoxicity of DC combination displays specific morphological hallmark and evolution in time, different to those described after doxorubicin single treatment. Neither amifostine nor dexrazoxane prevented development of cardiomyopathy induced by DC treatment.

Synthesis, structure and characterization of novel Cd(II) and Zn(II) complexes with the condensation product of 2-formylpyridine and selenosemicarbazide Antiproliferative activity of the synthesized complexes and related selenosemicarbazone complexes.

Two novel Cd(II) and Zn(II) complexes with the condensation product of 2-formylpyridine and selenosemicarbazide were synthesized. The structure of Cd(II) complex was determined by X-ray crystallography. The ligand is coordinated in a neutral form via pyridine and azomethine nitrogen atoms and the selenium donor. The cadmium ion completes its five-coordination by two chloride ligands, forming a square-pyramidal geometry. The structure of Zn(II) complex was established by analysis of spectroscopic data, which indicated coordination of the ligand as a bidentate via the selenium and the azomethine nitrogen atoms. The cytotoxic activity of the newly synthesized complexes, as well as if five structurally related complexes and the ligand evaluated against eight tumor cell lines. The new Cd(II) complex showed the highest activity similar to cisplatin with IC50 less than 10muM for all cell lines. Cell cycle distribution and apoptosis study showed that Cd(II) complex and cisplatin might have some similarity in anticancer activity, which was not the case for cisplatin and other studied complexes. Effects of the complexes on matrix metalloproteinases (MMPs) MMP-9 and MMP-2 was also studied. Cd(II) and Zn(II) complexes and cisplatin increased MMP-2 activity in supernatants of tested cells, while Ni(II) complex with the same ligand decreased the activity, implying a possible activity in preventing tumor invasion and metastasis processes.

Novel trans-dichloridoplatinum(II) complexes with 3- and 4-acetylpyridine: Synthesis, characterization, DFT calculations and cytotoxicity.

Novel complexes of platinum(II) with 3- (1) or 4-acetylpyridine (2) have been synthesized and characterized by elemental analyses, IR, (1)H and (13)C NMR spectroscopy. Single crystal X-ray diffraction revealed the trans geometry of complex 2. DFT calculations confirm formation of trans isomers for both complexes. The complexes have been tested for their cytotoxicity against HeLa (human cervical cancer), U2OS (human osteosarcoma), U2OScisR (human osteosarcoma cisplatin resistant), B16 (murine melanoma), MDA-453, MDA-361, and MCF-7 (human breast cancer), LS-174 (human colon cancer) and FemX (human melanoma) cell lines. The most promising compound trans-dichloridobis(4-acetylpyridine)platinum(II) (2) overcomes cisplatin resistance of U2OScisR cells after 48h of drug exposure.

Molecular targeting agents in renal cell carcinoma: present strategies and future perspectives.

Treatment options for metastatic renal cell carcinoma (RCC) have been limited due to its resistance to chemotherapy and radiotherapy. Benefits from immunotherapeutic agents provide only a small subset of patients. During the past decade major advances have been made toward understanding the molecular basis of RCC development. Such acquired knowledge has offered unique opportunities for the development of molecular targeting agents. These agents are predominately small molecules or monoclonal antibodies that exert their action through modulation of protein activity or inhibition of amplified signals directly implicated in disease mechanism. To date, some of newly molecular targeted agents have entered advanced phases of clinical development, received marketing authorization by regulatory agencies and have opened a possibility of multiple treatment options. This article overviews current knowledge in RCC molecular pathology with recent clinical data, and discuss present strategies for future development of targeted therapies.

Sunitinib, sorafenib and mTOR inhibitors in renal cancer.

Understanding the alterations in cellular protein interactions and their relations to genetic mutations that cause renal cell carcinoma (RCC) provides a unique opportunity for the development of disease-specific therapy for patients with advanced forms of this disease. There is substantial evidence of an association between mutation on von Hippel-Lindau (VHL) gene and the earliest stages of tumorigenesis of RCC. The main consequence of VHL loss is the upregulation of downstream proangiogenic factors leading to highly vascular tumors. Overexpression of hypoxia inducible factor (HIF) is also caused by the mammalian target of rapamycin (mTOR), a key component of signaling pathways inside the cell, involved in cell proliferation. The inhibition of proangiogenic factors and mTOR was the main idea behind the development of new targeted agents in advanced RCC. Since December 2005, 3 targeted agents have been approved by the U.S. Food and Drug Administration (FDA) for the treatment of advanced RCC: sorafenib, sunitinib and temsirolimus. Sorafenib and sunitinib are synthetic, orally active agents shown to directly inhibit vascular endothelial growth factor receptors -2 and -3 (VEGFR-2, VEGFR-3) and platelet-derived growth factor receptor beta (PDGFR-beta), while temsirolimus is an mTOR inhibitor. Recent clinical studies form the basis for new guidelines for the treatment of advanced RCC: sorafenib should be used as a second-line treatment, sunitinib as the first-line therapy for good and intermediate-risk patients, and temsirolimus should be considered as first-line treatment for poor-risk patients. Future approaches to targeted therapy should focus on optimizing the use of current active drugs, exploring their combinations or investigating their sequential use. In addition, it is important to define the mechanisms of resistance on their use and to further investigate biomarkers and enhance treatment efficacy for the individual patients. The development of these targeted therapies represents an exciting step forward in the treatment of advanced RCC.

Effects of dexrazoxane and amifostine on evolution of Doxorubicin cardiomyopathy in vivo.

Doxorubicin is one of the most active drugs in oncology, with cardiotoxicity as a serious side effect of its application. The aim of this study was to investigate dexrazoxane and amifostine impact on the evolution of myocardial changes induced by doxorubicin. BalbC female mice were treated with doxorubicin only (10 mg/kg, single intravenous push), or with dexrazoxane (200 mg/kg, intraperitoneal [ip]) or amifostine (200 mg/kg, ip) 60 mins or 30 mins prior to treatment with doxorubicin, respectively. Blood sampling for determination of conventional serum-marker activity was performed 48 hrs later. The grade of histopathology changes was evaluated by light microscopy 1.5 and 3 months after treatments using the Billingham scoring method. Control groups consisted of nontreated mice. After doxorubicin-only treatment, the grade of heart tissue damage was found to increase in the period between 1.5 and 3 months. A similar but less intense progression was also detected in amifostine-pretreated animals, with significant difference among median Billingham scores between the two time points. The pretreatment with dexrazoxane suspended expansion of tissue lesions in time. Changes in serum enzyme activity revealed two correlations: the greater reduction in alpha-hydroxybutyrate dehydrogenase (alpha-HBDH) leakage is associated with a lower percentage of damaged tissue, and the creatine kinase to alpha-HBDH percent of difference ratio being greater than one is correlated with limited spreading of pathological lesions. Our results indicate that the development of doxorubicin-induced heart failure is based on a slow and persistent expansion of pathological process even long after the completion of the treatment. Dexrazoxane has proved to be successful and superior over amifostine against such an evolution of doxorubicin cardiomyopathy.

Activity of d,l-alpha-tocopherol (vitamin E) against cardiotoxicity induced by doxorubicin and doxorubicin with cyclophosphamide in mice.

The aim of this study was to investigate the cardioprotective activity of vitamin E against doxorubicin alone and doxorubicin in combination with cyclophosphamide in mice. Female BalbC/NIH mice were treated with vitamin E (100 IU/kg, orally) 24 hr before single bolus doses of doxorubicin (10 mg/kg, intravenously), or doxorubicin and cyclophosphamide (150 mg/kg, intraperitoneally). Non-treated animals served as negative controls, while positive control groups received doxorubicin or doxorubicin and cyclophosphamide. For evaluation, serum enzyme activity of aspartate aminotransferase (AST), lactate dehidrogenase (LDH), alpha-hydroxybutirate dehydrogenase (alpha-HBDH), and creatine kinase (CK) at 48 hr and histopathology examination of the heart tissue (Billigham rules) at 1.5 and 3 months followed to treatments were used. In sera of mice treated with vitamin E prior to doxorubicin, the creatine kinase and % alpha-HBDH activity were significantly reduced, compared to positive control. Histopathology changes (scored as 1.5 at 1.5 and 3 months respectively) were not significant compared to negative control at both time points of examination. In animals which received vitamin E before doxorubicin and cyclophosphamide, none of the serum enzymes was significantly reduced compared to positive control, but non-significant increase in AST and creatine kinase activity was detected (3% and 16.57% respectively). The degree of myocardial damage was significantly higher compared to non-treated group (2.0 and 2.5 at 1.5 and 3 months respectively). Current results show that vitamin E in single oral dose failed to inhibit acute cardiotoxic activity of doxorubicin, but suspended further progression of the heart muscle damage over the time. On the contrary, vitamin E did not attain any cardioprotection against doxorubicin and cyclophosphamide in combination.