This work presents a deeper pharmacological evaluation of two formerly prepared and characterized, and highly in vitro cytotoxic platinum(II) oxalato complexes [Pt(ox)(L1)2] (1) and [Pt(ox)(L2)2] (2), containing the derivatives of cyclin-dependent kinase inhibitor (CDKi) seliciclib ((R)-roscovitine, CYC202) coordinating as N-donor carrier ligands, i.e., 2-(1-ethyl-2-hydroxyethylamino)-N6-(4-methoxybenzyl)-9-isopropyladenine (L1) and 2-chloro-N6-(2,4-dimethoxybenzyl)-9-isopropyladenine (L2). The positive results of in vitro cytotoxicity screening on human cancer cell lines (HeLa, HOS, A2780, A2780R, G361 and MCF7 with IC50 at low micromolar levels) published previously, motivated us to perform extended preclinical in vitro experiments to reveal the mechanisms associated with the induction of cancer cell death. In addition, the in vivo antitumor activity was evaluated using the mouse lymphocytic leukaemia L1210 model. The obtained results revealed that complex 1 exceeds the antitumor effect of cisplatin (as for the extension of life-span of mice) and shows far less adverse effects as compared to reference drug cisplatin. The in vitro and ex vivo studies of cellular effects and molecular mechanisms of cell death induction showed that the mechanism of action of complex 1 is essentially different from that of cisplatin. The obtained results showed a possible way how to obtain antitumor active platinum(II) oxalato complexes with better therapeutic profile than contemporary used platinum-based therapeutics.

• Keywords
• Antitumor activity, Ex vivo, In vivo, Platinum(II) complexes, Seliciclib derivatives,
• MeSH
• Apoptosis drug effects   MeSH
• Cisplatin adverse effects   MeSH
• Humans MeSH
• Lymphoma pathology   MeSH
• Mice, Inbred DBA MeSH
• Mice MeSH
• Cell Line, Tumor MeSH
• Organoplatinum Compounds chemistry   MeSH
• Oxalates chemistry   MeSH
• Antineoplastic Agents chemistry   pharmacology   MeSH
• Roscovitine chemistry   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Cisplatin MeSH
• Organoplatinum Compounds MeSH
• Oxalates MeSH
• Antineoplastic Agents MeSH
• Roscovitine MeSH

4-Azaindole (1H-pyrrolo[3,2-b]pyridine; 4aza) and its N1-alkylated derivative N1-isopropyl-4-azaindole (1-(propan-2-yl)-1H-pyrrolo[3,2-b]pyridine; ip4aza) have been used for the preparation of the cis-diiodido-platinum(II) complexes cis-[Pt(4aza)2I2] (1), cis-[PtI2(ip4aza)2] (2), cis-[Pt(4aza)I2(NH3)] (3) and cis-[PtI2(ip4aza)(NH3)] (4). The prepared complexes were thoroughly characterized (e.g., multinuclear NMR spectroscopy and ESI mass spectrometry) and their in vitro cytotoxicity was assessed at human ovarian carcinoma (A2780), cisplatin-resistant ovarian carcinoma (A2780R) and colon carcinoma (HT-29) cell lines, where they showed, in some cases, significantly higher activity than the used reference-drug cisplatin. The results of in vitro cytotoxicity testing at the A2780 and A2780R cells indicated that alkylation of the 4-azaindole moiety at the position of the N1 atom had a positive biological effect, because the ip4aza-containing complexes 2 and 4 showed significantly (p < 0.005) higher cytotoxicity than 4aza-containing analogues 1 and 3. The resistance factors (A2780R/A2780 model) equalled 0.8-1.4, indicating the ability of complexes 1-4 to overcome the acquired resistance of the A2780 cells against cisplatin. Complexes 1 and 2 revealed low toxicity against primary culture of human hepatocytes. The flow cytometry studies of the A2780 cell cycle modification showed that complexes 1-4 induce different cell cycle perturbations as compared with cisplatin, thus suggesting a different mechanism of their antitumor action.

• Keywords
• 4-Azaindole, Cytotoxicity, In vitro, Iodido, Platinum(II) complexes,
• MeSH
• Cell Cycle drug effects   MeSH
• Hydrophobic and Hydrophilic Interactions MeSH
• Indoles chemistry   pharmacology   MeSH
• Humans MeSH
• Molecular Structure MeSH
• Tumor Cells, Cultured MeSH
• Organoplatinum Compounds chemical synthesis   chemistry   pharmacology   MeSH
• Cell Proliferation drug effects   MeSH
• Antineoplastic Agents chemical synthesis   chemistry   pharmacology   MeSH
• Drug Screening Assays, Antitumor MeSH
• Dose-Response Relationship, Drug MeSH
• Structure-Activity Relationship MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• 4-azaindole MeSH Browser
• Indoles MeSH
• Organoplatinum Compounds MeSH
• Antineoplastic Agents MeSH

A series of platinum(II) diiodido complexes containing 7-azaindole derivatives, having the general formula cis-[PtI2(naza)2] (1-8), has been prepared and thoroughly characterized, including X-ray structure analysis of cis-[PtI2(2Me4Claza)2]∙DMF (8∙DMF; 2Me4Claza = 2-methyl-4-chloro-7-azaindole). Complexes showed high in vitro cytotoxicity against nine human cancer cell lines (IC50 ranging from 0.4 to 12.8 μM), including the cisplatin-resistant ovarian cancer cell line (A2780R; IC50 = 1.0-3.5 μM). The results of in vivo testing, using the L1210 lymphocytic leukaemia model, at the equimolar doses of Pt with cisplatin (2 mg/kg) confirmed the activity of complex 8 comparable to cisplatin. From the mechanistic point of view, evaluated ex vivo by Western blot analyses on the samples of isolated tumour tissues, the treatment of the animals with complex 8, contrary to cisplatin, decreased the levels of tumour suppressor p53 and increased significantly the amount of intracellular anti-apoptotic protein MCL-1L (37 kDa). Additionally, the active form of caspase 3 was significantly elevated in the sample of tumour tissues treated with complex 8, indicating that the activation of p53-independent cell-death pathway was initiated. The light and electron microscopy observations of the cancerous tissues revealed necrosis as a dominant mechanism of cell death, followed by scarce signs of apoptosis. The additional results (e.g. in vitro interaction experiments with selected biomolecules, cell cycle perturbations, gel electrophoretic studies on pUC19 plasmid DNA) supported the hypothesis that the complexes might be involved in the mechanism of action quite different from cisplatin.

• MeSH
• Apoptosis drug effects   MeSH
• Cell Cycle drug effects   MeSH
• Drug Resistance, Neoplasm drug effects   MeSH
• Cisplatin administration & dosage   MeSH
• Indoles administration & dosage   chemistry   MeSH
• Caspase 3 genetics   MeSH
• Humans MeSH
• Molecular Structure MeSH
• Cell Line, Tumor MeSH
• Tumor Suppressor Protein p53 genetics   MeSH
• Ovarian Neoplasms drug therapy   genetics   pathology   MeSH
• Organoplatinum Compounds administration & dosage   chemistry   MeSH
• Plasmids drug effects   MeSH
• Cell Proliferation drug effects   MeSH
• Cell Survival drug effects   MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• 7-azaindole dimer MeSH Browser
• Cisplatin MeSH
• Indoles MeSH
• Caspase 3 MeSH
• Tumor Suppressor Protein p53 MeSH
• Organoplatinum Compounds MeSH

A series of organometallic half-sandwich dichloridoruthenium(II) complexes of the general formula [Ru(η6-p-cym)(naza)Cl2] (1-8; p-cym = p-cymene; naza = 7-azaindole or its derivatives) was synthesised and fully characterized by elemental analysis, mass spectrometry, and infrared and multinuclear NMR spectroscopy. A single-crystal X-ray structural analysis of [Ru(η6-p-cym)(2Me4Claza)Cl2] (6) revealed a typical piano-stool geometry with an N7-coordination mode of 2-methyl-4-chloro-7-azaindole (2Me4Claza). The complexes have been found to be inactive against human ovarian cancer cell line A2780 up to the highest applied concentration (IC50 > 50.0 μM). An inactivity of the complexes is caused by their instability in water-containing solvents connected with a release of the naza N-donor ligand, as proved by the detailed 1H NMR, mass spectrometry and fluorescence experiments.

• MeSH
• Mass Spectrometry MeSH
• Humans MeSH
• Models, Molecular MeSH
• Molecular Structure MeSH
• Cell Line, Tumor MeSH
• Nuclear Magnetic Resonance, Biomolecular MeSH
• Antineoplastic Agents chemical synthesis   chemistry   pharmacology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antineoplastic Agents MeSH

The cis-[PtCl2(naza)2] complexes (1-3) containing monosubstituted 7-azaindole halogeno-derivatives (naza), showed significantly higher activity than cisplatin towards ovarian carcinoma A2780, its cisplatin-resistant variant A2780R, osteosarcoma HOS, breast carcinoma MCF7 and cervix carcinoma HeLa cell lines, with the IC50 values of 3.8, 3.5, 4.5, 2.7, and 9.2 μM, respectively, obtained for the most active complex 3. As for 4 and 5 having disubstituted 7-azaindoles in their molecule, the significant cytotoxicity was detected only for 4 against A2780 (IC50 = 4.8 μM), A2780R (IC50 = 3.8 μM) and HOS (IC50 = 4.3 μM), while 5 was evaluated as having only moderate antiproliferative effect against the mentioned cancer cell lines with IC50 = 33.4, 24.7 and 46.7 μM, respectively. All the studied complexes 1-5 effectively avoided the acquired resistance of ovarian carcinoma cell line. On the other hand, the complexes did not reveal any inhibition activity on the purified 20S proteasome from the A2780 cells. The representative complexes 3 and 5 showed low ability to be hydrolysed, but their stability was markedly lowered in the presence of physiological sulphur-containing biomolecule glutathione (GSH), as proved by the 1H NMR spectroscopy and mass spectrometry studies. A rate of interaction of the studied complexes with GSH was affected by an addition of another mechanistically relevant biomolecule guanosine monophosphate. The differences in interactions of 3 and 5 with GSH correlate well with their different cytotoxicity profiles.

• MeSH
• Drug Resistance, Neoplasm MeSH
• Cisplatin chemistry   pharmacology   MeSH
• Glutathione chemistry   MeSH
• HeLa Cells MeSH
• Mass Spectrometry MeSH
• Indoles chemistry   pharmacology   MeSH
• Humans MeSH
• MCF-7 Cells MeSH
• Molecular Structure MeSH
• Nuclear Magnetic Resonance, Biomolecular MeSH
• Organoplatinum Compounds chemistry   pharmacology   MeSH
• Antineoplastic Agents chemistry   pharmacology   MeSH
• Cell Survival drug effects   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• 7-azaindole dimer MeSH Browser
• Cisplatin MeSH
• Glutathione MeSH
• Indoles MeSH
• Organoplatinum Compounds MeSH
• Antineoplastic Agents MeSH

The moderate-to-high in vitro cytotoxicity against ovarian A2780 (IC50 = 4.7-14.4 μM), prostate LNCaP (IC50 = 18.7-30.8 μM) and prostate PC-3 (IC50 = 17.6-42.3 μM) human cancer cell lines of the platinum(II) cyclobutane-1,1'-dicarboxylato complexes [Pt(cbdc)(naza)2] (1-6; cbdc = cyclobutane-1,1'-dicarboxylate(2-); naza = halogeno-substituted 7-azaindoles), derived from the anticancer metallodrug carboplatin, are reported. The complexes containing the chloro- and bromo-substituted 7-azaindoles (1, 2, and 4-6) showed a significantly higher (p < 0.05) cytotoxicity against A2780 cell line as compared to cisplatin used as a reference drug. Addition of the non-toxic concentration (5.0 μM) of L-buthionine sulfoximine (L-BSO, an effective inhibitor of γ-glutamylcysteine synthase) markedly increases the in vitro cytotoxicity of the selected complex 3 against A2780 cancer cell line by a factor of about 4.4. The cytotoxicity against A2780 and LNCaP cells, as well as the DNA platination, were effectively enhanced by UVA light irradiation (λmax = 365 nm) of the complexes, with the highest phototoxicity determined for compound 3, resulting in a 4-fold decline in the A2780 cells viability from 25.1% to 6.1%. The 1H NMR and ESI-MS experiments suggested that the complexes did not interact with glutathione as well as their ability to interact with guanosine monophosphate. The studies also confirmed UVA light induced the formation of the cis [Pt(H2O)2(cbdc`)(naza)] intermediate, where cbdc` represents monodentate-coordinated cbdc ligand, which is thought to be responsible for the enhanced cytotoxicity. This is further supported by the results of transcription mapping experiments showing that the studied complexes preferentially form the bifunctional adducts with DNA under UVA irradiation, in contrast to the formation of the less effective monofunctional adducts in dark.

• MeSH
• DNA Adducts chemistry   genetics   MeSH
• Buthionine Sulfoximine pharmacology   MeSH
• DNA Breaks, Double-Stranded drug effects   radiation effects   MeSH
• Spectrometry, Mass, Electrospray Ionization MeSH
• Indoles chemistry   pharmacology   MeSH
• Carboplatin chemistry   pharmacology   MeSH
• Nucleic Acid Conformation MeSH
• Humans MeSH
• Molecular Structure MeSH
• Cell Line, Tumor MeSH
• Neoplasms genetics   pathology   MeSH
• Antineoplastic Agents chemistry   pharmacology   MeSH
• Proton Magnetic Resonance Spectroscopy MeSH
• Drug Synergism MeSH
• Ultraviolet Rays * MeSH
• Cell Survival drug effects   genetics   radiation effects   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• 7-azaindole dimer MeSH Browser
• DNA Adducts MeSH
• Buthionine Sulfoximine MeSH
• Indoles MeSH
• Carboplatin MeSH
• Antineoplastic Agents MeSH

A series of gold(I) complexes involving triphenylphosphine (PPh3) and one N-donor ligand derived from deprotonated mono- or disubstituted hypoxanthine (HLn) of the general composition [Au(Ln)(PPh3)] (1-9) is reported. The complexes were thoroughly characterized, including multinuclear high resolution NMR spectroscopy as well as single crystal X-ray analysis (for complexes 1 and 3). The complexes were screened for their in vitro cytotoxicity against human cancer cell lines MCF7 (breast carcinoma), HOS (osteosarcoma) and THP-1 (monocytic leukaemia), which identified the complexes 4-6 as the most promising representatives, who antiproliferative activity was further tested against A549 (lung adenocarcinoma), G-361 (melanoma), HeLa (cervical cancer), A2780 (ovarian carcinoma), A2780R (ovarian carcinoma resistant to cisplatin), 22Rv1 (prostate cancer) cell lines. Complexes 4-6 showed a significantly higher in vitro anticancer effect against the employed cancer cells, except for G-361, as compared with the commercially used anticancer drug cisplatin, with IC50 ≈ 1-30 µM. Anti-inflammatory activity was evaluated in vitro by the assessment of the ability of the complexes to modulate secretion of the pro-inflammatory cytokines, i.e. tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), in the lipopolysaccharide-activated macrophage-like THP-1 cell model. The results of this study identified the complexes as auspicious anti-inflammatory agents with similar or better activity as compared with the clinically applied gold-based antiarthritic drug Auranofin. In an effort to explore the possible mechanisms responsible for the biological effect, the products of interactions of selected complexes with sulfur-containing biomolecules (L-cysteine and reduced glutathione) were studied by means of the mass-spectrometry study.

• MeSH
• Anti-Inflammatory Agents chemistry   pharmacology   toxicity   MeSH
• Cell Line MeSH
• Hypoxanthine chemistry   pharmacology   toxicity   MeSH
• Humans MeSH
• Macrophages drug effects   metabolism   MeSH
• Molecular Conformation MeSH
• Models, Molecular MeSH
• Molecular Structure MeSH
• Cell Line, Tumor MeSH
• Nuclear Magnetic Resonance, Biomolecular MeSH
• Organophosphorus Compounds chemistry   pharmacology   toxicity   MeSH
• Antineoplastic Agents chemistry   pharmacology   toxicity   MeSH
• Gold chemistry   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Anti-Inflammatory Agents MeSH
• Hypoxanthine MeSH
• Organophosphorus Compounds MeSH
• Antineoplastic Agents MeSH
• triphenylphosphine MeSH Browser
• Gold MeSH