Structure-cytotoxicity relationship for different types of mononuclear platinum(II) complexes with 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine

Platinum(II) Complexes with Bulky Disubstitute Triazolopyrimidines as Promising Materials for Anticancer Agents

Herein, we present dicarboxylate platinum(II) complexes of the general formula [Pt(mal)(DMSO)(L)] and [Pt(CBDC)(DMSO)(L)], where L is dbtp 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine) or ibmtp (7-isobutyl-5-methyl-1,2,4- triazolo[1,5-a]pyrimidine), as prospective prodrugs. The platinum(II) complexes were synthesized in a one-pot reaction between cis-[PtCl₂(DMSO)₂], silver malonate or silver cyclobutane-1,1-dicarboxylate and triazolopyrimidines. All platinum(II) compounds were characterized by FT-IR, and ¹H, ¹³C, ¹⁵N and ¹⁹⁵Pt NMR; and their square planar geometries with one monodentate N(3)-bonded 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidine, one S-bonded molecule of dimethyl sulfoxide and one O,O-chelating malonato (1, 2) or O,O-chelating cyclobutane-1,1-dicarboxylato (3, 4) was determined. Additionally, [Pt(CBDC)(dbtp)(DMSO)] (3) exhibited (i) substantial in vitro cytotoxicity against the lung adenocarcinoma epithelial cell line (A549) (IC₅₀ = 5.00 µM) and the cisplatin-resistant human ductal breast epithelial tumor cell line (T47D) (IC₅₀ = 6.60 µM); and (ii) definitely exhibited low toxicity against normal murine embryonic fibroblast cells (BALB/3T3).

First dinuclear rhodium(II) complexes with triazolopyrimidines and the prospect of their potential biological use

Five novel rhodium(II) complexes of general formula [Rh₂(μ-OOCCH₃)₄L₂], where L is a triazolopyrimidine derivative, in particular dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp) for (1), 5,7-diethyl-1,2,4-triazolo[1,5-a]pyrimidine (detp) for (2), 7-isobutyl-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine (ibmtp) for (3), 7-hydroxy-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine (HmtpO) for (4) and 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) for (5) are reported. These first representatives of paddle-wheel dirhodium complexes with triazolopyrimidines have been characterized by IR and NMR spectroscopy as well as by single-crystal X-ray diffraction studies. Three of the new complexes (1), (2) and (5) were thoroughly screened in vitro for their cytotoxicity against human breast cancer cell line MCF-7 and L929 murine fibroblast cells. Favorably, they show significantly less effective inhibition on the cell growth of L929 than cisplatin under identical conditions. Complexes (1) and (5) display moderate cytotoxic activity (IC₅₀ = 16.3-21.5 μM) against MCF-7 cells which is induced via reactive oxygen species-independent pathways. Extensive studies of rhodium complexes (1), (2) and (5) against microorganisms have shown that the tested compounds exhibit antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) while (5) significantly inhibited the growth of Malassezia furfur. The highest antibacterial, and antifungal activity, was observed for (5).

Synthesis and characterization of Pt(ii)-based potent anticancer agents with minimum normal cell toxicity: their bio-activity and DNA-binding properties

The Cis-Pt(ii)-dichloro complex and its different intercellular derivates show good DNA-binding, comparable anticancer properties and less normal cell toxicity than cisplatin, and initiates cell death through apoptosis.

VP, Misini B, Das P, Dasgupta S, Linert W, Moi SC. Synthesis, biological evaluation, substitution behaviour and DFT study of Pd(ii) complexes incorporating benzimidazole derivative

Pd(ii) complexes with good DNA/BSA binding ability exhibit cytotoxicity comparable to cisplatin on different cancer cells along with reduced toxicity towards normal cells.

Rational design of dicarboxylato platinum(II) complexes with purine-mimetic ligands as novel anticancer agents

Six novel platinum(II) complexes containing purine-mimetic ligands (5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp), 7-isobutyl-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine (ibmtp), 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp)) and dicarboxylato ligands (glutarato (glut) or cyclobutane-1,1-dicarboxylato (CBDC)) have been prepared and characterized with multinuclear magnetic resonance (¹H, ¹³C, ¹⁵N, ¹⁹⁵Pt) NMR, infrared (IR) and X-ray crystallography. Spectroscopic data in solid state and in solution unambiguously confirm the square-planar geometry of Pt(II) with two monodentate N3-bonded 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidine ligands and one O-chelating dicarboxylato ligand. Next, the effect of all the platinum(II) compounds on the viability of normal or cancer cells and their putative mechanisms of action have been investigated. Of the studied platinum(II) complexes, two ([Pt(glut)(dbtp)₂] and [Pt(CBDC)(dbtp)₂]) overcame the cisplatin resistance in human ovarian tumor cells (A2780cis or OVCAR-3) and arrested the cell cycle at S phase in mice mammary gland cancer cells (4T1), which indicates a mechanism of action different from that of cisplatin. Interestingly, preliminary in vivo toxicity assays revealed that both compounds tested in mice ([Pt(glut)(dbtp)₂] 3 and [Pt(CBDC)(dbtp)₂] 6) were less toxic in vivo than cisplatin or oxaliplatin. Additionally, compound 6 did not cause myelosuppression and showed over fivefold less accumulation in the liver than its glutarato analog 3.

Experimental and theoretical investigation of the complexation of 5-methyl-7-isobutyl-1,2,4-triazolo[1,5-a]pyrimidine with platinum(ii) ions

Dichlorido platinum(ii) complexes with 5-methyl-7-isobutyl-1,2,4-triazolo[1,5-a]pyrimidine (ibmtp) were synthesized and characterized by various tools: IR, ¹H, ¹³C, ¹⁵N, ¹⁹⁵Pt NMR and DFT calculations.

Nanovehicles as a novel target strategy for hyperthermic intraperitoneal chemotherapy: a multidisciplinary study of peritoneal carcinomatosis

In general, detection of peritoneal carcinomatosis (PC) occurs at the late stage when there is no treatment option. In the present study, we designed novel drug delivery systems that are functionalized with anti-CD133 antibodies. The C1, C2 and C3 complexes with cisplatin were introduced into nanotubes, either physically or chemically. The complexes were reacted with anti-CD133 antibody to form the labeled product of A0-o-CX-chem-CD133. Cytotoxicity screening of all the complexes was performed on CHO cells. Data showed that both C2 and C3 Pt-complexes are more cytotoxic than C1. Flow-cytometry analysis showed that nanotubes conjugated to CD133 antibody have the ability to target cells expressing the CD133 antigen which is responsible for the emergence of resistance to chemotherapy and disease recurrence. The shortest survival rate was observed in the control mice group (K3) where no hyperthermic intraperitoneal chemotherapy procedures were used. On the other hand, the longest median survival rate was observed in the group treated with A0-o-C1-chem-CD133. In summary, we designed a novel drug delivery system based on carbon nanotubes loaded with Pt-prodrugs and functionalized with anti-CD133 antibodies. Our data demonstrates the effectiveness of the new drug delivery system and provides a novel therapeutic modality in the treatment of melanoma.

Synthesis of platinum(II) complexes of 2-cycloalkyl-substituted benzimidazoles and their cytotoxic effects

Five novel Pt(II) complexes with some 2-cycloalkyl-substituted benzimidazole carrier-ligands were synthesized and evaluated for their in vitro cytotoxic activities against HeLa and OVCAR-3 cell lines. A cell viability test revealed that [dichloro-bis(2-cycloheptylbenzimidazole) platinum(II)] is less cytotoxic than cisplatin, and its cytotoxic effect can be compared with that of carboplatin. Flow cytometric analysis revealed that this complex at 117 μM concentration causes apoptosis in approx. 72 % of the OVCAR-3 cell population. In addition, the complex was found to cause an increase in the SubG1 population of both OVCAR-3 and HeLa cells and to cause less apoptosis in HeLa cells than cisplatin.

Synthesis, in-vitro cytotoxic activity and DNA interactions of new dicarboxylatoplatinum(II) complexes with 2-hydroxymethylbenzimidazole as carrier ligands

Objectives

The aim of this study was to investigate the in-vitro cytotoxic activity of new platinum(II) complexes on the human HeLa (ER−), MCF-7 (ER+) and MDA-MB 231 (ER−) cell lines. Furthermore, we investigated plasmid DNA interactions and inhibition of BamHI and HindIII restriction enzyme activity of the complex 1–4,7.

Methods

Platinum(II) complexes were synthesised from precursor complexes of [PtL2Cl2] and [PtL2I2]. Their cytotoxic activity was tested by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Their plasmid DNA interactions and restriction enzyme activities were also investigated using the agarose gel electrophoresis method.

Key findings

The growth inhibitory effect results showed that the cytotoxicity of complex 2 was found to be the most active complex among the synthesised complexes.

Conclusions

The MTT results showed that complex 2 was found to be cytotoxic equal to cisplatin and higher than carboplatin against the MCF-7 and MDA-MB-231 cell lines. Furthermore, the estrogen or progesterone co-treatment slightly increased the cytotoxicity of complex 2, the cisplatin and carboplatin compared with the complex 2 tested alone in 50 μm concentration. According to plasmid DNA interaction and the restriction studies, complexes 1–4,7 modified the tertiary structure of pBR322 plasmid DNA, and complexes 2–4 prevented enzyme digestion at high concentrations.

Synthesis, characterization and antitumor properties of two highly cytotoxic ruthenium(iii) complexes with bulky triazolopyrimidine ligands

Two ruthenium(III) complexes composed of 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) ligands were prepared and structurally characterized by X-ray crystallography, IR, UV-Vis, EPR spectroscopies and cyclic voltammetry (CV). The crystal structures of trans-[RuCl(3)(H(2)O)(dbtp)(2)] 1 and mer-[RuCl(3)(dbtp)(3)]·0.815OCMe(2) 2 showed slightly distorted octahedral geometries with two 1 or three 2 monodentate dbtp ligands bound in a head-to-head orientation. In both complexes, the heterocyclic dbtp ligands were bound to the ruthenium(III) ion through the N3 nitrogen atom. A cytotoxicity assay of both ruthenium(III) compounds against two human cell lines (A549 - non-small cell lung carcinoma and T47D - breast carcinoma) was performed. The ruthenium(III) complexes showed excellent cytotoxicity with IC(50) values in the range of 0.02-2.4 μM against both cancer cell lines. In addition, the in vitro cytotoxic values of the ruthenium(III) compounds were 35-times for 1 and 172-times for 2 higher against T47D than the clinically used antitumor drug cisplatin.