Modulation of drug sensitivity in yeast cells by the ATP‐binding domain of human DNA topoisomerase IIα

Epipodophyllotoxins are effective antitumour drugs that trap eukaryotic DNA topoisomerase II in a covalent complex with DNA. Based on DNA cleavage assays, the mode of interaction of these drugs was proposed to involve amino acid residues of the catalytic site. An in vitro binding study, however, revealed two potential binding sites for etoposide within human DNA topoisomerase IIα (htopoIIα), one in the catalytic core of the enzyme and one in the ATP‐binding N‐terminal domain. Here we have tested how N‐terminal mutations that reduce the affinity of the site for etoposide or ATP affect the sensitivity of yeast cells to etoposide. Surprisingly, when introduced into full‐length enzymes, mutations that lower the drug binding capacity of the N‐terminal domain in vitro render yeast more sensitive to epipodophyllotoxins. Consistently, when the htopoIIα N‐terminal domain alone is overexpressed in the presence of yeast topoII, cells become more resistant to etoposide. Point mutations that weaken etoposide binding eliminate this resistance phenotype. We argue that the N‐terminal ATP‐binding pocket competes with the active site of the holoenzyme for binding etoposide both in cis and in trans with different outcomes, suggesting that each topoisomerase II monomer has two non‐equivalent drug‐binding site

N-thioalkylcarbazoles derivatives as new antiproliferative agents: synthesis, characterisation and molecular mechanism evaluation

Synthetic or natural carbazole derivatives constitute an interesting class of heterocycles, which showed several pharmaceutical properties and occupied a promising place as antitumour tools in preclinical studies. They target several cellular key-points, e.g. DNA and Topoisomerases I and II. The most studied representative, i.e. Ellipticine, was introduced in the treatment of metastatic breast cancer. However, because of the onset of dramatic side effects, its use was almost dismissed. Many efforts were made in order to design and synthesise new carbazole derivatives with good activity and reduced side effects. The major goal of the present study was to synthesise a series of new N-thioalkylcarbazole derivatives with anti-proliferative effects. Two compounds, 5a and 5c, possess an interesting anti-proliferative activity against breast and uterine cancer cell lines without affecting non-tumoural cell lines viability. The most active compound (5c) induces cancer cells death triggering the intrinsic apoptotic pathway by inhibition of Topoisomerase II

NHC-Ag(I) and NHC-Au(I) Complexes with N-Boc-Protected α-Amino Acidate Counterions Powerfully Affect the Growth of MDA-MB-231 Cells

N-Heterocyclic carbene (NHC) metal complexes are attracting scientists' interest as an alluring class of metallodrugs. Indeed, the versatile functionalization of NHC ligands makes them optimal scaffolds to be developed in medicinal chemistry. Besides, amino acids are great biological ligands for metals, such as silver and gold, even though their use is still under-investigated. Aiming to shed light on the anticancer properties of this kind of complex, we investigated a series of silver and gold complexes, stabilized by NHC ligands and bearing carboxylate salts of tert-butyloxy-carbonyl (Boc)-N-protected glycine and l-phenyl-alanine as anionic ligands. The most active complexes, AuM1Gly and AuM1Phe, powerfully affect the growth of MDA-MB-231 breast cancer cells, with IC50 values in the low nanomolar range. Further studies demonstrated the blockade of the human topoisomerase I activity and actin polymerization reaction at 0.001 mu M. These unique features make these complexes very interesting and worthy to be used for future in vivo studies

N-Heterocyclic Carbene (NHC) Silver Complexes as Versatile Chemotherapeutic Agents Targeting Human Topoisomerases and Actin

In recent years, the number of people suffering from cancer has risen rapidly and the World Health Organization and U.S. and European governments have identified this pathology as a priority issue. It is known that most bioactive anticancer molecules do not target a single protein but exert pleiotropic effects, simultaneously affecting multiple pathways. In our study, we designed and synthesized a new series of silver N-heterocyclic carbene (NHC) complexes [(NHC)2Ag]+[AgX2]− (X=iodide or acetate). The new complexes were active against two human breast cancer cell lines, MCF-7 and MDA-MB-231. These compounds showed multiple target actions as anticancer, by inhibiting in vitro the activity of the human topoisomerases I and II and interfering with the cytoskeleton dynamic, as also confirmed by in silico studies. Moreover, the antimicrobial activity of these silver complexes was studied against Gram-positive/negative bacteria. These dual properties provide a two-tiered approach, making these compounds of interest to be further deepened for the development of new chemotherapeutic agents

N-Heterocyclic Carbene (NHC) Silver Complexes as Versatile Chemotherapeutic Agents Targeting Human Topoisomerases and Actin

In recent years, the number of people suffering from cancer has risen rapidly and the World Health Organization and U.S. and European governments have identified this pathology as a priority issue. It is known that most bioactive anticancer molecules do not target a single protein but exert pleiotropic effects, simultaneously affecting multiple pathways. In our study, we designed and synthesized a new series of silver N-heterocyclic carbene (NHC) complexes [(NHC)(2)Ag](+)[AgX2](-) (X=iodide or acetate). The new complexes were active against two human breast cancer cell lines, MCF-7 and MDA-MB-231. These compounds showed multiple target actions as anticancer, by inhibiting in vitro the activity of the human topoisomerases I and II and interfering with the cytoskeleton dynamic, as also confirmed by in silico studies. Moreover, the antimicrobial activity of these silver complexes was studied against Gram-positive/negative bacteria. These dual properties provide a two-tiered approach, making these compounds of interest to be further deepened for the development of new chemotherapeutic agents

Synthesis of Novel N-Heterocyclic Carbene-Ruthenium (II) Complexes, “Precious” Tools with Antibacterial, Anticancer and Antioxidant Properties

Ruthenium N-heterocyclic carbene (Ru-NHC) complexes show interesting physico-chemical properties as catalysts and potential in medicinal chemistry, exhibiting multiple biological activities, among them anticancer, antimicrobial, antioxidant, and anti-inflammatory. Herein, we designed and synthesized a new series of Ru-NHC complexes and evaluated their biological activities as anticancer, antibacterial, and antioxidant agents. Among the newly synthesized complexes, RANHC-V and RANHC-VI are the most active against triple-negative human breast cancer cell lines MDA-MB-231. These compounds were selective in vitro inhibitors of the human topoisomerase I activity and triggered cell death by apoptosis. Furthermore, the Ru-NHC complexes’ antimicrobial activity was studied against Gram-positive and -negative bacteria, revealing that all the complexes possessed the best antibacterial activity against the Gram-positive Staphylococcus aureus, at a concentration of 25 µg/mL. Finally, the antioxidant effect was assessed by DPPH and ABTS radicals scavenging assays, resulting in a higher ability for inhibiting the ABTS•+, with respect to the well-known antioxidant Trolox. Thus, this work provides encouraging insights for further development of novel Ru-NHC complexes as potent chemotherapeutic agents endowed with multiple biological properties. © 2023 by the authors

Yeni tiyazol türevlerinin sentezi ve antikanser etki çalışmaları

Bu çalışmada, yeni tiyazolil hidrazonlar (2a-p) sentezlenmiş ve K562 kronik miyeloid lösemi hücre dizisi üzerine sitotoksik etkileri için araştırılmıştır. Bu bileşikler arasında, 2h, 2j ve 2l kodlu bileşikler K562 hücre dizisine karşı güçlü antikanser aktivite göstermiştir. Bu bileşiklerin diğer lösemi (HL-60, MT-2 ve Jurkat) hücreleri ve periferik kan mononükleer hücreleri üzerine sitotoksik etkileri belirlenmiştir. Özellikle 4-(4-(metilsülfonil)fenil)-2-[2-((1,3-benzodioksol-4-il)metilen)hidrazinil]tiyazol (2j) yüksek selektivite indeksi (SI>11.27) ile K562 hücre dizisine karşı imatinibe (IC50= 6.84±1.11 µM) benzer antikanser aktivite (IC50= 8.87±1.93 µM) göstermiştir. Bileşik 2j'nin HL-60, Jurkat ve MT-2 hücreleri üzerinde imatinibden daha etkili olduğu bulunmuştur. Seçici antikanser aktivitesi nedeniyle bileşik 2j, K562 hücreleri üzerindeki apoptotik etkisi ve sekiz farklı tirozin kinaz üzerindeki inhibitör etkileri için araştırılmıştır. Bileşik 2j, imatinibden daha fazla apoptozu indüklemiş ve ABL1 kinaza karşı güçlü inhibitör aktivite (IC50= 5.37±1.17 µM) göstermiştir. Bileşiğin ABL1 kinazın (PDB kodu: 1IEP) ATP bağlanma bölgesine bağlanma modunun araştırılması için, MOE 2018.01 programı kullanılarak moleküler docking çalışması yapılmıştır. Bileşik 2j, güçlü etkileşimler oluşturarak ABL1 kinazın ATP bağlanma bölgesine yüksek affinite göstermiştir. In vitro ve in silico çalışmalar, ABL1 kinaz inhibitör aktivite için metilsülfonil sübstitüentinin önemini göstermiştir

Yeni tiyazol türevlerinin sentezi ve antikanser etki mekanizmalarının araştırılması

Bu çalışmada, yeni tiyazolil hidrazon türevleri (2a-l) sentezlenmiş ve bu bileşiklerin A549 insan akciğer adenokarsinom ve CCD-19Lu insan akciğer fibroblast hücre dizilerine karşı sitotoksik aktiviteleri değerlendirilmiştir. Seçici antikanser etki gösteren bileşiklerin apoptoz, kaspaz-3 ve Akt üzerine etkileri de araştırılmıştır. Triflorometil sübstitüe bileşik 2g (IC50= 3.37±0.15 µM), siyano sübstitüe bileşik 2c (IC50= 4.47±0.90 µM) ve kloro sübstitüe bileşik 2e'nin (IC50= 5.23±0.45 µM); A549 hücrelerine karşı cisplatinden (IC50= 6.97±2.61 µM) daha seçici ve güçlü antikanser etki gösterdikleri tespit edilmiştir. Özellikle 2-(2-([2,2'-bitiyofen]-5-ilmetilen)hidrazinil)-4-(4-siyanofenil)tiyazol (2c), A549 hücrelerinde cisplatine kıyasla apoptozu daha güçlü indüklemiş ve daha fazla kaspaz-3 aktivasyonuna neden olmuştur. Ayrıca bileşik 2c (IC50= 0.46±0.03 µM) Akt inhibitörü GSK690693 bileşiğinden (IC50= 4.97±0.06 µM) çok daha güçlü Akt inhibitörü etki göstermiştir. Moleküler docking çalışmasına göre, bu bileşik Akt substrat bağlanma bölgesine yüksek affinite göstererek Trp80 amino asit kalıntısı ile güçlü etkileşimler oluşturmuştur. In silico çalışmalar ile iyi bir farmakokinetik profile sahip oral biyoyararlanımı yüksek ilaç adayı bir bileşik olarak öngörülen 2c kodlu bileşiğin A549 hücre dizisi üzerine in vitro sitotoksik ve apoptotik etkilerini Akt inhibisyonu yoluyla gösterdiği tespit edilmiştir