Thiosemicarbazone Derivatives Developed to Overcome COTI-2 Resistance

COTI-2 is currently being evaluated in a phase I clinical trial for the treatment of gynecological and other solid cancers. As a thiosemicarbazone, this compound contains an N,N,S-chelating moiety and is, therefore, expected to bind endogenous metal ions. However, besides zinc, the metal interaction properties of COTI-2 have not been investigated in detail so far. This is unexpected, as we have recently shown that COTI-2 forms stable ternary complexes with copper and glutathione, which renders this drug a substrate for the resistance efflux transporter ABCC1. Herein, the complex formation of COTI-2, two novel terminal N-disubstituted derivatives (COTI-NMe2 and COTI-NMeCy), and the non-substituted analogue (COTI-NH2) with iron, copper, and zinc ions was characterized in detail. Furthermore, their activities against drug-resistant cancer cells was investigated in comparison to COTI-2 and Triapine. These data revealed that, besides zinc, also iron and copper ions need to be considered to play a role in the mode of action and resistance development of these thiosemicarbazones. Moreover, we identified COTI-NMe2 as an interesting new drug candidate with improved anticancer activity and resistance profile

Thiosemicarbazone Derivatives Developed to Overcome COTI-2 Resistance

COTI-2 is currently being evaluated in a phase I clinical trial for the treatment of gynecological and other solid cancers. As a thiosemicarbazone, this compound contains an N,N,S-chelating moiety and is, therefore, expected to bind endogenous metal ions. However, besides zinc, the metal interaction properties of COTI-2 have not been investigated in detail so far. This is unexpected, as we have recently shown that COTI-2 forms stable ternary complexes with copper and glutathione, which renders this drug a substrate for the resistance efflux transporter ABCC1. Herein, the complex formation of COTI-2, two novel terminal N-disubstituted derivatives (COTI-NMe2 and COTI-NMeCy), and the non-substituted analogue (COTI-NH2) with iron, copper, and zinc ions was characterized in detail. Furthermore, their activities against drug-resistant cancer cells was investigated in comparison to COTI-2 and Triapine. These data revealed that, besides zinc, also iron and copper ions need to be considered to play a role in the mode of action and resistance development of these thiosemicarbazones. Moreover, we identified COTI-NMe2 as an interesting new drug candidate with improved anticancer activity and resistance profile

New findings on the antiproliferative activity of the silver(I) complex with 5-fluorouracil against human multi-resistant NCI/ADR-RES ovarian tumor cells

Metal complexes with antitumor activities have been studied as an alternative to overcome tumor resistance to current pharmaceuticals. Recently, we described the synthesis of a silver(I) complex with 5-fluorouracil (Ag-5fu) with an effective activity in vitro against human multi-resistant ovarian tumor cells (NCI/ADR-RES) when compared to 5-fluorouracil (5fu) and cisplatin. Therefore, for a better understanding of the effect of Ag-5fu and its precursors 5fu and silver(I), the compounds were evaluated by colony formation capacity and flow cytometry assays to analyze cell cycle and cell death induction [phosphatidylserine residues (PS) exposition, multicaspases activation, production of reactive oxygen species (ROS) and mitochondrial membrane depolarization] on NCI/ADR-RES tumor cells. As observed for 5fu, Ag-5fu was able to promote G1 phase arrest and to totally inhibit colony formation. Besides, as observed to AgNO3, Ag-5fu promoted a potent PS externalization and multicaspases activation with loss of plasmatic membrane integrity. None of the compounds induced reactive oxygen species (ROS) generation. The Ag-5fu promoted mitochondrial membrane depolarization over time. The results suggest that Ag-5fu may induce regulated cell death in NCI/ADR-RES cells probably by intrinsic apoptosis. Silver (I) and 5fu play different roles on the effect of Ag-5fu in NCI/ADR-RES cells, and the activity of the Ag-5fu complex seems to be more than a simple combination of the activities of free 5fu and silver(I) ions60359368CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP442123/2014-0não tem2015/25114-4; 2018/12062-

Stereoselective Arylation of Substituted Cyclopentenes by Substrate-Directable Heck–Matsuda Reactions: A Concise Total Synthesis of the Sphingosine 1‑Phosphate Receptor (S1P₁) Agonist VPC01091

We describe herein an efficient and diastereoselective substrate-directable Heck–Matsuda reaction with nonactivated five-membered olefins. The carbamate acts as the main directing group in the arylation process allowing the synthesis of several functionalized aryl cyclopentenes in good to excellent diastereoselectivities (>85:15) and in isolated yields ranging from 41 to 90%. No double bond isomerizations were observed in these Heck reactions, and the newly created benzylic centers were preserved in all cases examined. The substrate directable Heck arylation approach was successfully applied in a straightforward total synthesis of the sphingosine 1-phosphate receptor-subtype 1 (S1P₁) agonist VPC01091 by a concise and practical route involving 5 steps in 40% overall yield

Schiff bases and their metal complexes to target and overcome (multidrug) resistance in cancer

Overcoming multidrug resistance (MDR) is one of the major challenges in cancer therapy. In this respect, Schiff base-related compounds (bearing a R1R2CNR3 bond) gained high interest during the past decades. Schiff bases are considered privileged ligands for various reasons, including the easiness of their preparation and the possibility to form complexes with almost all transition metal ions. Schiff bases and their metal complexes exhibit many types of biological activities and are used for the treatment and diagnosis of various diseases. Until now, 13 Schiff bases have been investigated in clinical trials for cancer treatment and hypoxia imaging. This review represents the first collection of Schiff bases and their complexes which demonstrated MDR-reversal activity. The areas of drug resistance covered in this article involve: 1) Modulation of ABC transporter function, 2) Targeting lysosomal ABCB1 overexpression, 3) Circumvention of ABC transporter-mediated drug efflux by alternative routes of drug uptake, 4) Selective activity against MDR cancer models (collateral sensitivity), 5) Targeting GSH-detoxifying systems, 6) Overcoming apoptosis resistance by inducing necrosis and paraptosis, 7) Reactivation of mutated p53, 8) Restoration of sensitivity to DNA-damaging anticancer therapy, and 9) Overcoming drug resistance through modulation of the immune system. Through this approach, we would like to draw attention to Schiff bases and their metal complexes representing highly interesting anticancer drug candidates with the ability to overcome MDR

Synthesis, characterization, crystal structure and in vitro antiproliferative assays of the 2-thiouracilato(triphenylphosphine) gold(I) complex

A gold(I) complex with triphenylphosphine and 2-thiouracil, named 2-thiouracilato(triphenylphosphine) gold(I) (Ph3P-Au-tuH), was synthesized and characterized by a set of chemical and spectroscopic techniques. By elemental and mass spectrometric (ESI-QTOF-MS) analyses, the molecular formula AuC22H18N2OSP was proposed, corresponding to a 1:1 metal/ligand composition. Spectroscopic studies based on the infrared (IR) and nuclear magnetic resonance (NMR) of H-1, C-13 and P-31 evidenced the conversion of the chlorido(triphenylphosphine)gold(I) into the 2-thiouracilato(triphenylphosphine) gold(I), with substitution of Cl- by thiouracil. The crystal structure of the Ph3P-Au-tuH complex was determined by single crystal X-ray diffraction and shows the coordination of 2-thiouracil to gold(I) by the thiol group. Further, the in vitro antiproliferative assays of the 2-thiouracilato(triphenylphosphine)gold(I) complex showed its high activity when compared to the chlorido(triphenylphosphine)gold(I) one against lung (NCI-H460) and colon (HT29) tumor cell lines, with total growth inhibition (TGI) values of 26.7 and 28.5 mu g mL(-1), respectively, and also high selectivity towards tumor cells when compared to the normal cell line (HaCat). In addition, the Ph3P-Au-tuH complex showed a TGI value lower than 0.25 mu g mL(-1) for the leukemia cell line (K-562) with a selectivity index (SI) of 24.4, exhibiting a better in vitro cytotoxicity and selectivity than doxorubicin against this specific cell1178169178CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP442123/2014-0não tem2015/25114-

Thiosemicarbazone Derivatives Developed to Overcome COTI-2 Resistance

COTI-2 is currently being evaluated in a phase I clinical trial for the treatment of gynecological and other solid cancers. As a thiosemicarbazone, this compound contains an N,N,S-chelating moiety and is, therefore, expected to bind endogenous metal ions. However, besides zinc, the metal interaction properties of COTI-2 have not been investigated in detail so far. This is unexpected, as we have recently shown that COTI-2 forms stable ternary complexes with copper and glutathione, which renders this drug a substrate for the resistance efflux transporter ABCC1. Herein, the complex formation of COTI-2, two novel terminal N-disubstituted derivatives (COTI-NMe2 and COTI-NMeCy), and the non-substituted analogue (COTI-NH2) with iron, copper, and zinc ions was characterized in detail. Furthermore, their activities against drug-resistant cancer cells was investigated in comparison to COTI-2 and Triapine. These data revealed that, besides zinc, also iron and copper ions need to be considered to play a role in the mode of action and resistance development of these thiosemicarbazones. Moreover, we identified COTI-NMe2 as an interesting new drug candidate with improved anticancer activity and resistance profile