Novel quinazolin-2-yl 1,2,3-triazole hybrids as promising multi-target anticancer agents: Design, synthesis, and molecular docking study.

In our study, a series of quinazoline-1,2,3-triazole hybrids (14a-r) have been designed and synthesized as multi-target EGFR, VEGFR-2, and Topo II inhibitors. All synthesized hybrids were assessed for their anticancer capacity. MTT assay revealed that compounds 14a, 14d, and 14k were the most potent hybrids against four cancer cell lines, HeLa, HePG-2, MCF-7, and HCT-116 at low micromolar range while exhibiting good selectivity against normal cell line WI-38. Sequentially, the three compounds were evaluated for EGFR, VEGFR-2, and Topo II inhibition. Compound 14d was moderate EGFR inhibitor (IC50 0.103 µM) compared to Erlotinib (IC50 0.049 µM), good VEGFR-2 inhibitor (IC50 0.069 µM) compared to Sorafenib (IC50 0.031 µM), and stronger Topo II inhibitor (IC50 19.74 µM) compared to Etoposide (IC50 34.19 µM) by about 1.7 folds. Compounds 14k and 14a represented strong inhibitory activity against Topo II with (IC50 31.02 µM and 56.3 µM) respectively, compared to Etoposide. Additionally, cell cycle analysis and apoptotic induction were performed. Compound 14d arrested the cell cycle on HeLa at G2/M phase by 17.53 % and enhanced apoptosis by 44.08 %. A molecular Docking study was implemented on the three hybrids and showed proper binding interaction with EGFR, VEGFR-2, and Topo II active sites.

Multi-target rational design and synthesis of novel diphenyl-tethered pyrazolopyrimidines targeting EGFR and topoisomerase II with potential DNA intercalation and apoptosis induction.

Herein, we envisioned the design and synthesis of novel pyrazolopyrimidines (confirmed by elemental analysis, 1H and 13C NMR, and mass spectra) as multitarget-directed drug candidates acting as EGFR/TOPO II inhibitors, DNA intercalators, and apoptosis inducers. The target diphenyl-tethered pyrazolopyrimidines were synthesized starting from the reaction of phenyl hydrazine and ethoxymethylenemalononitrile to give aminopyrazole-carbonitrile 2. The latter hydrolysis with NaOH and subsequent reaction with 4-chlorobenzaldhyde afforded the corresponding pyrazolo[3,4-d]pyrimidin-4-ol 4. Chlorination of 4 with POCl3 and sequential reaction with different amines afforded the target compounds in good yields (up to 73 %). The growth inhibition % of the new derivatives (6a-m) was investigated against different cancer and normal cells and the IC50 values of the most promising candidates were estimated for HNO97, MDA-MB-468, FaDu, and HeLa cancer cells. The frontier derivatives (6a, 6i, 6k, 6l, and 6m) were pursued for their EGFR inhibitory activity. Compound 6l decreased EGFR protein concentration by a 6.10-fold change, compared to imatinib as a reference standard. On the other side, compounds (6a, 6i, 6k, 6l, and 6m) underwent topoisomerase II (TOPO II) inhibitory assay. In particular, compounds 6a and 6l exhibited IC50s of 17.89 and 19.39 µM, respectively, surpassing etoposide with IC50 of 20.82 µM. Besides, the DNA fragmentation images described the great potential of both candidates 6a and 6l in inducing DNA degradation at lower concentrations compared to etoposide and doxorubicin. Moreover, compound 6l, with the most promising EGFR/TOPO II inhibition and DNA intercalation, was selected for further investigation for its apoptosis induction ability by measuring caspases 3, 7, 8, and 9, Bax, p53, MMP2, MMP9, and BCL-2 proteins. Additionally, molecular docking was used to explain the SAR results based on the differences in the molecular features of the investigated congeners and the target receptors' topology.

Pharmacophore-based, rationale design, and efficient synthesis of novel tetrahydrobenzo[b]thiophene candidates as potential dual Topo I/II inhibitors and DNA intercalators.

A series of tetrahydrobenzo[b]thiophene derivatives was designed and synthesized as dual topoisomerase (Topo) I/II inhibitors implicating potential DNA intercalation. Ethyl-2-amino-3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophene-4-carboxylate (1) was prepared by modification of the Gewald reaction procedure using a Fe2O3 nanocatalyst and then it was used as a building block for the synthesis of tetrahydrobenzo[b]thiophene candidates (2-14). Interestingly, compound 14 showed the best cytotoxic potential against hepatocellular, colorectal, and breast cancer cell lines (IC50 = 7.79, 8.10, and 3.53 µM), respectively, surpassing doxorubicin at breast cancer (IC50 = 4.17 µM). Meanwhile, the Topo I and II inhibition assay displayed that compound 3 could exhibit the best inhibitory potential among the investigated candidates (IC50 = 25.26 and 10.01 nM), respectively, in comparison to camptothecin (IC50 = 28.34 nM) and doxorubicin (IC50 = 11.01 nM), as reference standards. In addition, the DNA intercalation assay showed that compound 14 could display the best binding affinity with an IC50 value of 77.82 µM in comparison to doxorubicin (IC50 = 58.03 µM). Furthermore, cell cycle and apoptosis analyses described that compound 3 prompts the G1 phase arrest in michigan cancer foundation-7 cancer cells and increases the apoptosis ratio by 29.31% with respect to untreated cells (2.25%). Additionally, the conducted molecular docking assured the promising binding of the investigated members toward Topo I and II with potential DNA intercalation. Accordingly, the synthesized compounds could be treated as promising anticancer candidates for future optimization.

Synthesis and cytotoxicity evaluation of DNA-interactive ß-carboline indolyl-3-glyoxamide derivatives: Topo-II inhibition and in silico modelling studies.

In a quest for effective cancer targeted drug therapy, a series of new ß-carboline tethered indole-3-glyoxylamide derivatives, conjoining salient pharmacophoric properties with prominent cytotoxicity, were synthesized. The in vitro cytotoxic ability of the compounds was established, and many of the compounds exhibited remarkable cytotoxicity (IC50 < 10 µM) on human cancer cell lines like HCT116, A549, SK-MEL-28, and MCF7. Precisely, compound 12x expressed the best cytotoxic potential against melanoma cancer cell line (SK-MEL-28) with an IC50 value of 4.37 µM. In addition, cytotoxicity evaluation against normal kidney cell line (NRK52E) entrenched the cytospecificity and selectivity index of 12x. The traditional apoptosis assays advised morphological and nuclear alterations such as apoptotic body formation, condensed/horseshoe-shaped/fragmented nuclei, and generation of ROS. The flow cytometric analysis revealed significant early and slight late-stage induction of apoptosis. The target-based physiochemical assays indicated the ability of compound 12x to bind with DNA and inhibition of Topoisomerase II. Moreover, molecular modeling studies affirm the excellent DNA intercalation potential and stabilized interactions of 12x with DNA base pairs. In silico prediction of physicochemical parameters revealed the promising drug-like properties of the synthesized derivatives.

Identification of new benzimidazole-triazole hybrids as anticancer agents: multi-target recognition, in vitro and in silico studies.

Multi-target inhibitors represent useful anticancer agents with superior therapeutic attributes. Here in, two novel series of benzimidazole-triazole hybrids were designed, synthesised as multi-target EGFR, VEGFR-2 and Topo II inhibitors, and evaluated for anticancer activity. Compounds 5a and 6g were the most potent analogues against four cancer cell lines, HepG-2, HCT-116, MCF-7 and HeLa, and were further evaluated for EGFR, VEGFR-2, and Topo II inhibition. Compound 5a was especially good inhibitor for EGFR (IC50 = 0.086 µM) compared to Gefitinib (IC50 = 0.052 µM), moderate VEGFR-2 inhibitor (IC50 = 0.107 µM) compared to Sorafenib (IC50 = 0.0482 µM), and stronger Topo II inhibitor (IC50 = 2.52 µM) than Doxorubicin (IC50 = 3.62 µM). Compound 6g exhibited moderate EGFR and VEGFR-2 inhibition and weaker Topo II inhibition. DNA binding assay, cell cycle analysis, apoptotic induction, molecular docking, and physicochemical studies were additionally implemented to explore the plausible mechanism of the active compounds.

Topo II inhibition and DNA intercalation by new phthalazine-based derivatives as potent anticancer agents: design, synthesis, anti-proliferative, docking, and in vivo studies.

This research presents the design and synthesis of a novel series of phthalazine derivatives as Topo II inhibitors, DNA intercalators, and cytotoxic agents. In vitro testing of the new compounds against HepG-2, MCF-7, and HCT-116 cell lines confirmed their potent cytotoxic activity with low IC50 values. Topo II inhibition and DNA intercalating activities were evaluated for the most cytotoxic members. IC50 values determination demonstrated Topo II inhibitory activities and DNA intercalating affinities of the tested compounds at a micromolar level. Amongst, compound 9d was the most potent member. It inhibited Topo II enzyme at IC50 value of 7.02 ± 0.54 µM with DNA intercalating IC50 of 26.19 ± 1.14 µM. Compound 9d was then subjected to an in vivo antitumor examination. It inhibited tumour proliferation reducing solid tumour volume and mass. Additionally, it restored liver enzymes, proteins, and CBC parameters near-normal, indicating a remarkable amelioration in their functions along with histopathological examinations.

Triazoloquinoxalines-based DNA intercalators-Topo II inhibitors: design, synthesis, docking, ADMET and anti-proliferative evaluations.

Sixteen [1, 2, 4]triazolo[4,3-a]quinoxalines as DNA intercalators-Topo II inhibitors have been prepared and their anticancer actions evaluated towards three cancer cell lines. The new compounds affected on high percentage of MCF-7. Derivatives 7e, 7c and 7b exhibited the highest anticancer activities. Their activities were higher than that of doxorubicin. Molecular docking studies showed that the HBA present in the chromophore, the substituted distal phenyl moiety and the extended linkers enable our derivatives to act as DNA binders. Also, the pyrazoline moiety formed six H-bonds and improved affinities with DNA active site. Finally, 7e, 7c and 7b exhibited the highest DNA affinities and act as traditional intercalators of DNA. The most active derivatives 7e, 7c, 7b, 7g and 6e were subjected to evaluate their Topo II inhibition and DNA binding actions. Derivative 7e exhibited the highest binding affinity. It intercalates DNA at IC50 = 29.06 µM. Moreover, compound 7e potently intercalates DNA at an IC50 value of 31.24 µM. Finally, compound 7e demonstrated the most potent Topo II inhibitor at a value of 0.890 µM. Compound 7c exhibited an equipotent IC50 value (0.940 µM) to that of doxorubicin. Furthermore, derivatives 7b, 7c, 7e and 7g displayed a high ADMET profile.

Antitumor Effect of Glandora rosmarinifolia (Boraginaceae) Essential Oil through Inhibition of the Activity of the Topo II Enzyme in Acute Myeloid Leukemia.

It was previously shown that the antitumor and cytotoxic activity of the essential oil (EO) extracted from the aerial parts of Glandora rosmarinifolia appears to involve a pro-oxidant mechanism in hepatocellular carcinoma (HCC) and in triple-negative breast cancer (TNBC) cell lines. Its most abundant compound is a hydroxy-methyl-naphthoquinone isomer. Important pharmacological activities, such as antitumor, antibacterial, antifungal, antiviral and antiparasitic activities, are attributed to naphthoquinones, probably due to their pro-oxidant or electrophilic potential; for some naphthoquinones, a mechanism of action of topoisomerase inhibition has been reported, in which they appear to act both as catalytic inhibitors and as topoisomerase II poisons. Our aim was to evaluate the cytotoxic activity of the essential oil on an acute myeloid leukemia cell line HL-60 and on its multidrug-resistant (MDR) variant HL-60R and verify its ability to interfere with topoisomerase II activity. MTS assay showed that G. rosmarinifolia EO induced a decrease in tumor cell viability equivalent in the two cell lines; this antitumor effect could depend on the pro-oxidant activity of EO in both cell lines. Furthermore, G. rosmarinifolia EO reduced the activity of Topo II in the nuclear extracts of HL-60 and HL-60R cells, as inferred from the inability to convert the kinetoplast DNA into the decatenated form and then not inducing linear kDNA. Confirming this result, flow cytometric analysis proved that EO induced a G0-G1 phase arrest, with cell reduction in the S-phase. In addition, the combination of EO with etoposide showed a good potentiation effect in terms of cytotoxicity in both cell lines. Our results highlight the antitumor activity of EO in the HL-60 cell line and its MDR variant with a peculiar mechanism as a Topo II modulator. Unlike etoposide, EO does not cause stabilization of a covalent Topo II-DNA intermediate but acts as a catalytic inhibitor. These data make G. rosmarinifolia EO a potential anticancer drug candidate due to its cytotoxic action, which is not affected by multidrug resistance.

Discovery of Quinacrine as a Potent Topo II and Hsp90 Dual-Target Inhibitor, Repurposing for Cancer Therapy.

Topo II and Hsp90 are promising targets. In this study, we first verified the structural similarities between Topo IIα ATPase and Hsp90α N-ATPase. Subsequently, 720 compounds from the Food and Drug Administration (FDA) drug library and kinase library were screened using the malachite green phosphate combination with the Topo II-mediated DNA relaxation and MTT assays. Subsequently, the antimalarial drug quinacrine was found to be a potential dual-target inhibitor of Topo II and Hsp90. Mechanistic studies showed that quinacrine could specifically bind to the Topo IIα ATPase domain and inhibit the activity of Topo IIα ATPase without impacting DNA cleavage. Furthermore, our study revealed that quinacrine could bind Hsp90 N-ATPase and inhibit Hsp90 activity. Significantly, quinacrine has broad antiproliferation activity and remains sensitive to the multidrug-resistant cell line MCF-7/ADR and the atypical drug-resistant tumor cell line HL-60/MX2. Our study identified quinacrine as a potential dual-target inhibitor of Topo II and Hsp90, depending on the ATP-binding domain, positioning it as a hit compound for further structural modification.

Development of ß-carboline-benzothiazole hybrids via carboxamide formation as cytotoxic agents: DNA intercalative topoisomerase IIα inhibition and apoptosis induction.

In quest of promising anticancer agents, the pharmacophores of natural (ß-carboline) and synthetic origin (benzothiazole) were adjoined by a carboxamide bridge and three-point diversification was accomplished. The in vitro cytotoxic ability of the compounds was established on adherent and suspension human cancer cell lines and compounds 8u and 8f advanced as pre-eminent molecules with IC50 values of 1.46 and 1.81 µM respectively in A549 cell line. The cytospecificity was entrenched for potent compounds 8u and 8f by evaluating against normal human lung epithelial cells and selectivity index was calculated. Furthermore, EtBr displacement, relative viscosity and gel-based topoisomerase II target assays unveiled the intercalative topo-II inhibitory capability and DNA binding studies (absorbance) revealed the dissociation constant (Kd) for compounds 8u and 8f as 98 and 103 µM respectively. Additionally, cell-based flow cytometric assays like Annexin-V/PI dual staining aids in the quantification of apoptosis induced and JC-1 staining disclosed the depolarization of mitochondrial membrane potential by compound 8u in A549 cells in a dose-dependent manner. Moreover, wound healing assay established the inhibition of in vitro cell migration by compound 8u on A549 cells. In addition, molecular docking studies proved the binding of compounds 8u and 8f in the active site of DNA complexed with topo IIα and stabilized by interactions with DNA base pairs and amino acid residues. Remarkably, the compounds 8u and 8f follow Lipinski's rule of five and are in the recommended range for Jorgensen's rule of three with a minimal violation and other pharmacokinetic parameters revealing druggability of the synthesized hybrids.

Design and synthesis of thiadiazolo-carboxamide bridged ß-carboline-indole hybrids: DNA intercalative topo-IIα inhibition with promising antiproliferative activity.

The conjoining of salient pharmacophoric properties directing the development of prominent cytotoxic agents was executed by constructing thiadiazolo-carboxamide bridged ß-carboline-indole hybrids. On the evaluation of in vitro cytotoxic potential, 12c exhibited prodigious cytotoxicity among the synthesized new molecules 12a-k, with an IC50 < 5 µM in all the tested cancer cell lines (A549, MDA-MB-231, BT-474, HCT-116, THP-1) and the best cytotoxic potential was expressed in lung cancer cell line (A549) with an IC50 value of 2.82 ± 0.10 µM. Besides, another compound 12a also displayed impressive cytotoxicity against A549 cell line (IC50: 3.00 ± 1.40 µM). Further target-based assay of these two compounds 12c and 12a revealed their potential as DNA intercalative topoisomerase-IIα inhibitors. Additionally, the antiproliferative activity of compound 12c was measured in A549 cells by traditional apoptosis assays revealing the nuclear, morphological alterations, and depolarization of membrane potential in mitochondria and externalization of phosphatidylserine in a concentration-dependent manner. Cell cycle analysis unveiled the G0/G1 phase inhibition and wound healing assay inferred the inhibition of in vitro cell migration by compound 12c in lung cancer cells. Remarkably, the safety profile of compound 12c was disclosed by screening against normal human lung epithelial cell line (BEAS-2B: IC50: 71.2 ± 7.95 µM) with a selectivity index range of 14.9-25.26. Moreover, Molecular modeling studies affirm the intercalative binding of compound 12c and 12a in the active pocket of topo-IIα. Furthermore, in silico prediction of physico-chemical parameters divulged the propitious drug-like properties of the synthesized derivatives.

Design, synthesis, bioevaluation of LFC- and PA-tethered anthraquinone analogues of mitoxantrone.

The clinical application of mitoxantrone (MTZ), a DNA-intercalating topoisomerase II (topo II) poison, has been largely limited by the risk of secondary tumor and severe myelosuppression. To develop more effective antineoplastic agents with less toxicity, a spectrum of anthraquinone analogues of MTZ were herein designed and synthesized based on the concept of 'enhancing protein backbone-binding', by rationally introducing hydrophobic long fatty acid chain (LFC) and hydrophilic polyamine (PA) components, which are reported to function as effective tumor-targeting tethers. The SAR exploration implicated that in our synthesized molecules, the introduction of both lipophilic LFC and hydrophilic PA fragment is plausibly beneficial to the anti-proliferative potency, with a certain degree of selectivity between the hematopoietic and solid malignant cells, which still need to be further accurately confirmed. Meanwhile, many compounds, the LFC-tethered 5d2 and PA-bridged 8c in particular, provided satisfactory topo IIα inhibition by acting as DNA non-intercalators, largely attributable to their strong adaptability to three binding regions (pocket I, II and III) and also the generated H-bonding interactions between inhibitors and key residues of topo IIα. In brief, 5d2 and 8c might be promising hits for further exploitation of more potent topo IIα inhibitors.

E17 exerts anti-tumor activity through inhibiting topo II-mediated chromosomes condensation in CRC cells.

Topo II inhibitors, e.g. etoposide, doxorubicin and mitoxantrone, etc., which exert their functions by trapping the covalent 'topo II-DNA cleavable complex' via intercalation into DNA base pairs, leading to DNA damage and degradation of topo II, and inducing decline of cell sensitivity and corresponding multidrug resistance (MDR). E17 is a recently identified topo II inhibitor in our lab which has validated to possess a strong topo II inhibitory activity on cell viability, colony formation, and cell migration. Especially, E17 can trigger G2/M cell cycle arrest through inhibiting chromosome condensation without causing obvious DNA damage in colorectal cancer (CRC) HCT116 cell. E17 can also induce the accumulation of topo II-DNA complex without leading to degradation of topo II, which was different from topo II inhibitors VP16 or ICRF-187, suggesting E17 might be a potential lead for further development by serving as a strong topo II inhibitor.

Expressions of Topo IIα and Ki67 in breast cancer and its clinicopathologic features and prognosis.

OBJECTIVE: Breast cancer is one of the most common malignant tumors in women, and its incidence in women has ranked the first place among all malignant cancers. The evolution of breast cancer which is highly heterogeneous is a complex biological process involving multiple factors, genes and stages. Therefore, studying the expression and interaction of related genes is of great significance to further revealing of the mechanism of the occurrence and development of breast cancer and reduction of its resistance to chemotherapy. The purpose of this study was to investigate expressions of Ki67 and Topoisomerase IIα (Topo IIα) in breast cancer tissues and to explore the relationship between expressions of Ki67 and Topo IIα and the pathological characteristics and prognosis of breast cancer. METHODS: Tissues with pathological changes and peripheral normal breast tissues were collected from 66 patients who underwent breast cancer treatment. Ki67 and Topo IIα in the breast cancer tissues and normal breast tissues were detected using immunohistochemical method. The relationships of Ki67 and Topo IIα with general clinicopathologic features and prognosis were analyzed. RESULTS: It was found that the positive expressions of Ki67 and Topo IIα in the breast cancer tissues were higher than those in the normal tissues; the positive expression rate of Ki67 was in a correlation with diameter of breast cancer and lymphatic metastasis (P<0.05); the positive expression rate of Topo IIα was in a correlation with clinical stage, diameter of cancer and lymphatic metastasis (P<0.05). Multi-factor logistic regression analysis suggested that lymphatic metastasis and clinical stage were the independent predictive factors for positive expression of Topo IIα and lymphatic metastasis was the independent predictive factor for positive expression of Ki-67. Breast cancer patients with negative Ki67 and Topo IIα had significantly higher local recurrence rate than those who had positive Ki67 and Topo IIα (P<0.05) after surgery. The median time to progression (TTP) of the patients with positive expression of Topo IIα was lower than that with negative expression (P<0.05). The median TTP of the patients with negative and positive expression of Ki67 had no significant difference (P>0.05). CONCLUSION: Topo IIα and Ki67 can be used for reflecting the proliferation activity of cancer cells and can affect the postoperative recurrence and survival time after surgery. They may be involved in the occurrence, development and metastasis of breast cancer. They are expected to be indicators in the prognosis prediction of breast cancer and potential treatment targets.

The molecular mechanism of anticancer action of novel octahydropyrazino[2,1-a:5,4-a']diisoquinoline derivatives in human gastric cancer cells.

Objective The aim of the current study was to examine the anticancer activity and the detailed mechanism of novel diisoquinoline derivatives in human gastric cancer cells (AGS). Methods The viability of AGS cells was measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Cell cycle analysis and apoptosis assay were performed by standard flow cytometric method. Confocal microscopy bioimaging was used to demonstrate the expression of pivotal proteins engaged in apoptosis (caspase-8, caspase-3, p53) and cell signaling (AKT, ERK1/2). Results All compounds decreased the number of viable cells in a dose-dependent manner after 24 and 48 h of incubation, although compound 2 was a more cytotoxic agent, with IC50 values of 21 ± 2 and 6 ± 2 µM, compared to 80 ± 2 and 45 ± 2 µM for etoposide. The cytotoxic and antiproliferative effects of novel compounds were associated with the induction of apoptosis. The highest percentage of early and late apoptotic cells was observed after 48 h of incubation with compound 2 (89.9%). The value was higher compared to compound 1 (20.4%) and etoposide (24.1%). The novel diisoquinoline derivatives decreased the expression of AKT and ERK1/2. Their mechanism was associated with p53-mediated apoptosis, accumulation of cells in the G2/M phase of cell cycle and inhibition of topoisomerase II. Conclusion These data strongly support compound 2 as a promising molecule for treatment of gastric cancer.

Synthesis and biological evaluation of 4ß-(thiazol-2-yl)amino-4'-O-demethyl-4-deoxypodophyllotoxins as topoisomerase-II inhibitors.

A series of 4ß-(thiazol-2-yl)amino-4'-O-demethyl-4-deoxypodophyllotoxins were synthesized, and their cytotoxicities were evaluated against four human cancer cell lines (A549, HepG2, HeLa, and LOVO cells) and normal human diploid fibroblast line WI-38. Some of the compounds exhibited promising antitumor activity and less toxicity than the anticancer drug etoposide. Among them, compounds 15 and 17 were found to be the most potent synthetic derivatives as topo-II inhibitors, and induced DNA double-strand breaks via the p73/ATM pathway as well as the H2AX phosphorylation in A549 cells. These compounds also arrested A549 cells cycle in G2/M phase by regulating cyclinB1/cdc2(p34). Taken together, these results show that a series of compounds are potential anticancer agents.

Correlation between the Expression of Topo IIα and Ki67 in breast cancer and its clinical Pathological characteristics.

OBJECTIVE: To investigate the expression of Topo IIα and Ki67 and its clinical significance. METHODS: The clinical pathological data of one hundred and sixteen invasive breast cancer patients who were admitted into our hospital from July 2013 to December 2015 and underwent radical mastectomy were retrospectively analyzed. The expression of topoisomerase (Topo) IIα and Ki67 was detected using immunohistochemical method, and the correlation between the two kinds of proteins and the general clinical pathological characteristics of the patients was analyzed. RESULTS: The positive expression rates of Topo IIα and Ki67 in breast cancer were 58.6% and 75% respectively. The expression of Topo IIα was in no apparent correlation with the age, tumor size, estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER-2) (P>0.05), but in a correlation with the number of metastatic lymph glands (P<0.05). The expression of Ki67 was in no apparent correlation with the age, tumor size, EP and HER-2, but in a correlation with the number of metastatic lymph glands and PR (P<0.05). The multi-factor logistic regression analysis results suggested that the number of metastatic lymph glands was the independent predictive factor of Topo IIα positive expression and the number of metastatic lymph glands and PR protein expression state are the independent predictive factors of Ki67 positive expression. CONCLUSION: Topo IIα and Ki67 can be regarded as the indicators for reflecting the proliferation activity of tumor cells, and the detection of Topo IIα and Ki67 expression is of great significance to the prognosis evaluation of breast cancer patients and clinical treatment.

Regulation of Hepatic Cholesteryl Ester Transfer Protein Expression and Reverse Cholesterol Transport by Inhibition of DNA Topoisomerase II.

Cholesteryl ester transfer protein (CETP) transfers cholesteryl esters from high density lipoprotein to triglyceride-rich lipoproteins. CETP expression can be transcriptionally activated by liver X receptor (LXR). Etoposide and teniposide are DNA topoisomerase II (Topo II) inhibitors. Etoposide has been reported to inhibit atherosclerosis in rabbits with un-fully elucidated mechanisms. In this study we determined if Topo II activity can influence cholesterol metabolism by regulating hepatic CETP expression. Inhibition of Topo II by etoposide, teniposide, or Topo II siRNA increased CETP expression in human hepatic cell line, HepG2 cells, which was associated with increased CETP secretion and mRNA expression. Meanwhile, inhibition of LXR expression by LXR siRNA attenuated induction of CETP expression by etoposide and teniposide. Etoposide and teniposide induced LXRα expression and LXRα/ß nuclear translocation while inhibiting expression of receptor interacting protein 140 (RIP140), an LXR co-repressor. In vivo, administration of teniposide moderately reduced serum lipid profiles, induced CETP expression in the liver, and activated reverse cholesterol transport in CETP transgenic mice. Our study demonstrates a novel function of Topo II inhibitors in cholesterol metabolism by activating hepatic CETP expression and reverse cholesterol transport.

A quinoxaline-based derivative exhibited potent and selective anticancer activity with apoptosis induction in PC-3 cells through Topo II inhibition.

Quinoxaline constitutes a variety of derivatives that exhibit a range of biological characteristics, including anti-inflammatory and antitumor effects, and their importance in therapeutic chemistry is rising. The cytotoxicity effects of four quinoxaline compounds (I, II, III, and IV) against liver cancer cells (HepG2), prostate cancer cells (PC-3), and normal cells (Vero) were evaluated using the MTT assay. Compounds III and IV had the most anti-proliferative effects and highly selective indices against PC-3 cells with IC50 values of 4.11 and 2.11 µM, respectively. The apoptotic cell death for compounds III and IV in PC-3 cells was investigated using cell cycle, Annexin V-FITC/PI double staining-based flow cytometry, and DNA fragmentation assay. Compounds III or IV arrested the cell cycle at the S phase and caused apoptosis in PC-3 cells. Compounds III and IV showed inhibitory effects against topoisomerase II enzyme with IC50 values 21.98 and 7.529 µM, respectively, when compared to doxorubicin as a reference drug. Western Blot analysis displayed that compound IV treatment has significantly upregulated the pro-apoptotic proteins (p53, caspase-3, caspase-8) and downregulated the anti-apoptotic protein Bcl-2 in PC-3 cells in a dose-dependent manner, leading to cell apoptosis. The molecular docking study exhibited that compound IV had a good binding affinity for inhibiting topoisomerase II, consistent with the apoptotic mechanism. In vivo study using Ehrlich solid tumor model demonstrated that compound IV significantly reduced tumor volume and weight in vivo with minimal toxicity. This study reveals significant evidence for the antitumor efficacy of compound IV against prostate cancer cells as a topoisomerase II inhibitor.Communicated by Ramaswamy H. Sarma.

New 1,3,4‒oxadiazole Quinazolines as Potential Anticancer Agents: Design, Synthesis, Biological Evaluation, and In silico Studies.

BACKGROUND: A novel series of 1,3,4‒oxadiazole connected to derivatives of quinazolinone (7a-e and 8a-f) was synthesized in the current investigation, and its anticancer and Topoisomerase‒ II inhibitory activity was evaluated. OBJECTIVE: These findings inspired the design, synthesis, and biological analysis of these 1,3,4‒oxadiazole-quinazolinone analogues as antiproliferative Topo‒II inhibitors. METHODS: The novel compound structures were determined using mass spectrometry and spectral methods (IR, NMR: 1H & 13C). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colourimetric assay has been used to evaluate the anticancer efficacy of these drugs, and Autodock 4.2 provides a description of the docking results. For the more active members, additional biological tests, such as the Topo‒II inhibition experiment, were performed. These compounds' physicochemical and ADMET characteristics were examined in more detail. RESULTS: In the experiment for antiproliferative activity, compounds 7d, 7e, 8c, 8e, and 8f demonstrated encouraging cytotoxicity findings against HCT‒116 and HepG2 cancer cell lines, with IC50 values ranging from 3.85 to 19.43 µM. Compounds 7d, 7e, and 8e were the most potent inhibitors of Topo II with IC50 values of 15.18, 17.55, and 12.59 µM, respectively. Additionally, the docked compound 8c showed the strongest conventional hydrogen bonds among the residues Leu507(B), Asn508(B), Asn520(B), and Glu522(B) in the Human topoisomerase‒IIß active site in the DNA complex (4G0U) when compared to the findings of docking experiments. CONCLUSIONS: New findings have discovered the fact that fused 1,3,4‒oxadiazole bearing quinazolinone contributed great significance in the field of medicinal chemistry due to their diverse biological properties. Finally, the in silico pharmacokinetic profile of all the synthesized derivatives was estimated using SwissADME, where some of the compounds followed Lipinski, Veber, Egan, and Muegge rules without deviation. The result of this activity advises that with a simple modification in structure, a potent anticancer agent can be generated with good efficacy.