Despite significant advances in cancer therapy, the discovery of new anticancer agents with improved efficacy remains an important challenge. Human DNA topoisomerases I and II are well-established therapeutic targets because of their essential roles in DNA replication and transcription. Accordingly, a series of novel etofenamate-based thiosemicarbazide, 1,3-thiazole, and 1,3,4-oxadiazole derivatives were designed and synthesized, including a new synthetic approach for the preparation of the oxadiazole derivatives, and evaluated as potential topoisomerase-targeting anticancer agents. All synthesized compounds were structurally characterized and evaluated for antiproliferative activity against the A549 human lung cancer cell line and for their inhibitory effects on human DNA topoisomerases I and II. Based on their overall biological performance, compounds 3h, 5 h, and 5i were selected for further biological characterization, including thioredoxin reductase 1 (TrxR1) inhibition, total oxidative status (TOS), Bax/Bcl-2 protein expression, Annexin V analysis, and crystal violet staining. Molecular docking studies were performed to investigate the binding modes of the lead compounds toward topoisomerases I and II. Biological evaluation identified compounds 3 h, 5h, and 5i as the most promising derivatives. Enzymatic assays revealed distinct topoisomerase inhibition profiles, with compound 5h acting as a selective topoisomerase I inhibitor and compound 5i exhibiting dual inhibitory activity against topoisomerases I and II. Molecular docking analyses supported these findings by revealing target-specific binding modes consistent with the observed inhibition profiles. Complementary cellular studies demonstrated TrxR1 inhibition, increased oxidative stress, apoptosis-associated cellular responses, and morphological alterations, providing additional mechanistic characterization of the lead compounds. Collectively, these findings establish topoisomerases I and II as relevant molecular targets for the synthesized series while broadening the biological characterization of the lead compounds through complementary cellular investigations. Compound 5i emerged as the most promising dual topoisomerase I/II inhibitor and represents a valuable lead for the further development of novel topoisomerase-targeting anticancer agents.

In today's world where current medical treatments have reached their peak, many highly effective drugs have been developed with various technologies and unfortunately, despite the development of sophisticated drugs, there are still incurable diseases in the world. However, due to the lack of sufficient funds on a global scale and the inability to access treatments due to the inadequacy of various health policies, many patients cannot be provided with the magnificent fountain of life called "treatment". To some extent, even the limited focus area on developing new scientific perspectives can be compatible with this sad result. The development of biotechnological drugs and their prominent applications in current treatments are increasingly receiving investment and are considered worthy of attention. In addition to the traditional production of many drugs used in treatment, technological developments inevitably change the fate of drug development. In this section, by giving a little favor, examples were presented where biotechnological drugs seem to have won the war against conventional drugs.

drugs. The reasons underlying this unique priority are that topoisomerase enzymes are indispensable for the cell's own life dynamics, in the synthesis of RNA and proteins in the cell, or more importantly, for the preservation of genetic material. These enzymes are similar in terms of structure and functionality in many living groups, and by having relatively similar activities, they enable the creation of controlled DNA breaks and the reunification of DNA fragments in the cell. In fact, they are a kind of problem solver regarding the use of narrow spaces with their activities that enable the separation of long DNA molecules, which can be considered as gigantic in size, depending on the cell area in which they are located. In our study, the anticancer activity of Roxithromycin has been evaluated by topoisomerase enzyme assay analyses. Given the growing body of evidence supporting the anticancer properties of certain antibiotics, we evaluated whether Roxithromycin has different targets than those known through its potential anticancer effects and interactions with topoisomerase enzymes. Our findings revealed that roxithromycin selectively inhibited topoisomerase II activity, but did not show any inhibitory effect on topoisomerase I.

This study involved the design, synthesis and evaluation of a series of novel thiosemicarbazide and thiazolylhydrazone derivatives. The synthesized compounds were tested for cytotoxic effects SH-SY5Y neuroblastoma cells, as well as NIH-3T3 normal cell line using the MTT assay. Among the tested compounds, 3b, 3d, 3i, 4b, 4d and 4i exhibited IC50 values ranging from 1.97 mu M to 3.22 mu M in the SH-SY5Y cancer cell line with lower cytotoxicity toward NIH-3T3 cells. Moreover, all compounds were also screened for their topoisomerase I and II inhibitory activity and compound 3b completely inhibited the topoisomerase I enzyme, whereas all compounds showed potent topoisomerase II inhibitory activity. Docking studies were performed to identify the mode of binding of the tested compounds to the active site of topoisomerase I and II. In conclusion, N-(4-(2-((2-chlor- ophenyl)carbamothioyl)hydrazine-1-carbonyl)phenyl)benzamide (3b) emerges as a promising inhibitor of topoisomerase I and II and holds potential as a lead compound in the quest for novel anticancer agents.

The discovery of many drugs in recent years provides a definitive solution in the treatment of various diseases, but today, despite the discovery of many effective anticancer drugs, there are various types of cancer that have limitations in treatment and are still not completely curable. Since most of these limitations are due to cancer cells gaining resistance or compounds only being effective in certain types of cancer cells, the search for more effective anticancer drugs that are also effective in these types of cancer is inevitable. Cabozantinib is in medical use as a highly effective anticancer drug in various types of cancer, such as medullary thyroid cancer and kidney cancer. The anticancer properties of the Cabozantinib compound have attracted more attention in recent years, however, more studies are needed to define the anticancer activities of this compound. In our study, the interactions of Cabozantinib with topoisomerase enzymes, were demonstrated through in vitro enzyme activity tests, and the anti-proliferative effect of Cabozantinib was studied on MCF7, A549 and PC3 cell lines. By analyzing the interactions of the Cabozantinib with topoisomerases, the action mechanisms of the compound at the molecular level was evaluated.

Cancer is a disease that occurs as a result of abnormal or uncontrolled growth of cells due to DNA damage, among many other causes. Certain cancer treatments aim to increase the excess of DNA breaks to such an extent that they cannot escape from the general mechanism of cell checkpoints, leading to the apoptosis of mutant cells. In this study, one of the Sarco-endoplasmic reticulum Ca2+ATPase (SERCA2a) inhibitors, Istaroxime, was investigated. There has been very limited number of articles so far reporting Istaroxime's anticancer activity; thus, we aimed to evaluate the anticancer effects of Istaroxime by cell proliferation assay and revealed the cytotoxic activity of the compound. We further determined the interaction of Istaroxime with topoisomerase enzymes through enzyme activity tests and detailed molecular modeling analysis. Istaroxime exhibited an antiproliferative effect on A549, MCF7, and PC3 cell lines and inhibited Topoisomerase I, suggesting that Istaroxime can act as a Topoisomerase I inhibitor under in vitro conditions. Molecular docking analysis supported the experimental observations. A chemical reactivity analysis of the Istaroxime molecule was made in the light of Density Functional Theory computations. For this aim, important chemical reactivity descriptors such as hardness, electronegativity, and electrophilicity were computed and discussed as detailed.

Because of the continuous need for efficient therapeutic agents against various kinds of cancers and infectious diseases, the pharmaceutical industry has to find new candidates and strategies to develop novel and efficient drugs. They increasingly use computational tools in R&D stages for screening extensive sets of drug candidates before starting pre-clinical and clinical trials. N-Heterocyclic carbenes (NHCs) can be evaluated as good drug candidates because they offer both anti-cancer and anti-inflammatory features with their general low-toxicity profiles. To date, different kinds of NHCs (Cu, Co, Ni, Au, Ag, Ru, etc.) have been synthesized and their therapeutic uses has been shown. Here, we have reviewed the recent studies focused on Ag(I)-NHC complexes and their anti-cancer activities. Also, existing examples of the usage of density functional theory and structure-activity relationship have been evaluated.

The aim of this study was to evaluate biologically active novel molecules having potentials to be drugs by their antitumor properties and by activities of apoptotic caspase and topoisomerase. Following syntheses of novel eight bis(α-aminoalkyl)phosphinic acid derivatives (4a-h) as a result of array of reactions, compounds were evaluated by cytotoxic effects in vitro on human breast cancer (MCF-7) and normal endothelial (HUVEC) cell lines. All phosphinic acid derivatives were effective for cytotoxicity on both MCF-7 and HUVEC lines, while 4c, 4e, and 4f compounds were found significantly more effective. For the evaluation of antitumor properties of compounds in a highly sensitive method, their effects on inhibiting topoisomerases I and II were investigated. Also, some of the bis(α-aminoalkyl)phosphinic acid derivatives (4a, 4e-h) showed nice inhibitory action against acetylcholinesterase and human carbonic anhydrase isoforms I and II.

Antikanser ilaclarin cogunun hucrede siklikla bulunan DNA topoizomeraz reaksiyonlari ile girisim yaparak etkinliklerini ortaya koydugu gosterilmistir. Nitekim kamfotekinin (camptothecin) topoizomeraz I enzimini hedefleyen bilesik olarak tanimlanmasindan itibaren sentetik ve dogal bilesiklerin farmasotik onemini degerlendirmek uzere biyolojik calismalarda bu enzimlerden genis olcude yararlanilmistir. Onemli sayida bilesigin topoizomeraz reaksiyonlari uzerinden sitotoksik etkinlige sahip olmalari nedeniyle asetonaftonun ve turevinin daha once rapor edilen fizyolojik aktivitelerinin topoizomeraz reaksiyonlarini icerip icermediklerinin arastirilmasi hedeflenmistir. Baslangic molekulu olan asetonaftonun (AN) biyoaktivitesi ile karsilastirilmak uzere bilesikte bulunan aminometilin biyoaktiviteye etkisi, Mannich bazi turevi olan piperidinopropiyonafton hidroklorur bilesigi (MB) ile topoizomeraz aktivite ve sitostatik aktivite olcumleri kullanilarak degerlendirilmistir. MB laboratuvarimizda sentezlenip karakterize edilmistir. Memeli DNA topoizomerazlari uzerindeki biyolojik aktivitelerini degerlendirmek uzere supersarmal plazmid relaksasyon ve dekatenasyon deneyleri gerceklestirilmistir. Ayrica HeLa, MCF7 ve A431 hucre hatlarinda sitostatik aktivite arastirilmistir. Verilerimize gore sitostatik degerlendirmelerden bagimsiz olarak MB, tip I ve tip II DNA topoizomeraz uzerinde dikkate deger bir etki gostermistir. MB, MCF7 hucrelerindeki proliferasyona karsi 27.62 µM olan IC50 degeri ile ortalama bir etki gostermistir. Bununla birlikte MB varligi topoizomeraz II dekatenasyon aktivitesini etkilemistir. In vitro kosullarda sonuclarimiz DNA topoizomerazlar ve kanser hucrelerinin proliferasyonu uzerindeki etkilerini direkt olarak aciklamamaktadir. Sonuclarimiz Mannich bazinin ilac gelistirme calismalarindaki potansiyel onemi uzerinden degerlendirilmistir.

A considerable number of agents with chemotherapeutic potentials reported over the past years were shown to interfere with the reactions of DNA topoisomerases, the essential enzymes that regulate conformational changes in DNA topology. Gossypol, a naturally occurring bioactive phytochemical is a chemopreventive agent against various types of cancer cell growth with a reported activity on mammalian topoisomerase II. The compounds targeting topoisomerases vary in their mode of action; class I compounds act by stabilizing covalent topoisomerase-DNA complexes resulting in DNA strand breaks while class II compounds interfere with the catalytic function of topoisomerases without generating strand breaks. In this study, we report Gossypol as the interfering agent with type I topoisomerases as well. We also carried out an extensive set of assays to analyze the type of interference manifested by Gossypol on DNA topoisomerases. Our results strongly suggest that Gossypol is a potential class II inhibitor as it blocked DNA topoisomerase reactions with no consequently formed strand breaks.

BACKGROUND/AIMS:Human Cytochrome P450 (CYP) comprises a multigene family of microsomal enzymes that metabolize a wide variety of xenobiotics, including drugs and carcinogens. Although the a number of CYP enzymes were also detected in epithelial cells along the gastrointestinal tract, little is known about the expression of CYP genes in gastric tissue.METHODOLOGY:In this study, the expression patterns of CYP isoforms was investigated in a total of 14 antral biopsy tissues obtained from the patients with either chronic gastritis (n = 6) or cancer (n = 8) by gene-specific real-time reverse transcriptase -PCR analyses. We employed primer sets specific for CYPs -1A1, -1A2, -2A6, -2B6, -2C, -2D6, -2E1, and -3A5.RESULTS:Among the isoforms CYP1A1, CYP2C and CYP2D6 gave rise to detectable mRNAs in all 14 gastric tissues while the mRNAs for the other CYPs were detected in some of the tissues. The expression patterns were compared to clinical parameters. There were no significant differences in the parameters between the two groups; however the mRNA expression of CYP2A6 was significantly higher in women than man (p < 0.05).CONCLUSIONS:Our data suggests that the CYP isoforms were independently expressed with respect to the pathological status in human gastric tissue.

1a A number of studies reported Mannich bases to manifest antimicrobial, cytotoxic, anticancer, anti-inflammatory, and anticonvulsant activities. A considerable number of therapeutically important cytotoxic compounds are active on DNA topoisomerases that regulate the DNA topology. In the present study we evaluated the biological activity of mono- Mannich bases, 1-aryl-3-phenethylamino-1-propanone hydrochlorides (- 10a), and semicyclic mono- Mannich bases, 3-aroyl-4-aryl-1-phenethyl-4-piperidinols (1b - 9b), synthesized in our laboratory. We employed androgen-independent human prostate cancer cells (PC-3) to assess the cytotoxicity of the compounds and extended the biological activity evaluation to cover supercoil relaxation assays of mammalian type I topoisomerases. Our results showed that the compounds had cytotoxicity within the 8.2 - 32.1 μM range, while two compounds gave rise to a comparable average value in topo I interference of 42% and 40% for 10a (with a hydroxy substituent on the phenyl ring from mono-Mannich bases) and 5b (with a fluoro substituent on the phenyl ring from the semicyclic mono-Mannich base series, piperidinols), respectively

Chalcones (1,3-diaryl-2-propen-1-ones) are alpha, beta-unsaturated ketones with cytotoxic and anticancer properties. Several reports have shown that compounds with cytotoxic properties may also interfere with DNA topoisomerase functions. Five derivatives of 4'-hydroxychalcones were examined for cytotoxicity against transformed human T (Jurkat) cells as well as plasmid supercoil relaxation experiments using mammalian DNA topoisomerase I. The compounds were 3-phenyl-1-(4'-hydroxyphenyl)-2-propen-1-one (I), 3-(p-methylphenyl)-1-(4'-hydroxyphenyl)-2-propen-1-one (II), 3-(p-methoxyphenyl)-1-(4'-hydroxyphenyl)-2-propen-1-one (III), 3-(p-chlorophenyl)-1-(4'-hydroxyphenyl)-2-propen-1-one (IV), and 3-(2- thienyl)-1-(4'-hydroxyphenyl)-2-propen-1-one (V). The order of the cytotoxicity of the compounds was; IV > III > II > I > V. Compound IV, had the highest Hammett and log P values (0.23 and 4.21, respectively) and exerted both highest cytotoxicity and strongest DNA topoisomerase I inhibition. Compounds I and II gave moderate interference with the DNA topoisomerase I while III & V did not interfere with the enzyme.

a Department of Medical Biology, Faculty of Medicine, Pamukkale University, Denizli, Turkey b Department of Medical Biology, School of Medicine, Cukurova University, Adana, Turkey c Department of Radiodiagnostics, School of Medicine, Cukurova University, Adana, Turkey d Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Ege University, Izmir, Turkey. Fax: (90)23 2388 5258. E-mail: zeki.topcu@ege.edu.tr e Present address: Department of Biochemistry, Faculty of Science, Ege University, Izmir, 35100, Turkey

Cytochrome P450 (CYP) is a heme-containing enzyme superfamily metabolizing a wide variety of xenobiotics, including drugs and carcinogens. The majority of CYP genes are expressed in the liver, however, some CYP isoforms are also reported for a number of extra hepatic tissues. We analyzed Cytochrome P450-2A6, -3A5 and -4B1 mRNAs using realtime reverse-transcriptase polymerase chain reaction (RT-PCR) in a total of 21 homogenized prostate tissues with or without malignancy. We detected a consistent expression of CYP2A6 and CYP3A5 in all, and of CYP4B1 in some (11/21) of the samples at mRNA level. Neither the histopathological status nor the smoking habit of the individuals affected CYP4B1 expression. Our results reflect possible roles for these particular CYPs in therapy and protection of prostate tissue.

Some acetophenone (CAS 98-86-2) derived bis Mannich bases, bis-(3-aryl-3-oxo-propyl)-methylamine hydrochlorides (B1-B5) and representative piperidinols, 4-aryl-3-arylcarbonyl-1-methyl-4-piperidinol hydrochlorides (C1, C2 and C5), which are the structural isomers of B1, B2 and B5, were synthesized and their effects on DNA topoisomerase I were tested. Aryl part was phenyl in B1 and C1, p-methylphenyl in B2 and C2, p-methoxyphenyl in B3, p-chlorophenyl in B4, and 2-thienyl in B5 and C5. The compounds' chemical structures were confirmed by UV, IR, 1H NMR, 13C NMR, ESI-MS spectra. The purity levels of the compounds were determined by elemental analysis. Among the compounds, B1-B5 and C5 were found to inhibit DNA topo isomerase I at varying degrees. The compounds B1-B5 and C5 manifested an average of 46%, 20%, 40%, 22%, 24% and 22% inhibition on topoisomerase I, respectively, suggesting that the cytotoxic actions of the compounds may be linked to DNA topoisomerase I inhibition. There was a significant negative correlation between the LC50 values reported and topoisomerase I inhibition among the compounds studied. The topoisomerase inhibiting effects of the compounds of the B series may be attributed to the linear structures of the compounds and the possible formation of the hydrogen bonds with the DNA nucleotides. Among the compounds studied, the most potent topoisomerase I inhibiting compounds B1 (46%) and B3 (40%) may serve as model compounds to develop new more potent topoisomerase inhibitors in future studies.

New mono Mannich bases, (2-(4-hydroxy-3-((4-substituephenylpiperazin-1-yl)methyl)benzylidene)-2,3-dihydro-1H-inden-1-one), were prepared to evaluate their cytotoxic/anticancer properties and also their inhibitory effects on human carbonic anhydrase I and II isoenzymes (hCA I and II). Amine part was changed as [N-phenylpiperazine (1), N-benzylpiperazine (2), 1-(2-fluorophenyl)piperazine (3), 1-(4-fluorophenyl)piperazine (4), 1-(2-methoxyphenyl)piperazine (5)]. The structure of the synthesized compounds was characterized by 1H NMR, 13C NMR and HRMS spectra. Cytotoxicity results of the series pointed out that the compound 4 had the highest tumor selectivity value (TS: 59.4) possibly by inducing necrotic cell death in series. Additionally, all compounds synthesized showed a good inhibition profile towards hCA I and II isoenzymes with the Ki values between 29.6 and 58.4 nM and 38.1–69.7 nM, respectively. These values were lower than the reference compound AZA. However, it seems that the compounds 4 and 2 can be considered as lead compounds of CA studies with the lowest Ki values in series for further designs.