Design, synthesis and antitumor activity of C3/C3 bis-fluoroquonolones cross-linked with [1,2,4]triazolo[3,4-b] [1,3,4]thiadiazole

A Comprehensive Review on Chemical Synthesis and Chemotherapeutic Potential of 3-Heteroaryl Fluoroquinolone Hybrids

Fluoroquinolones have been studied for more than half a century. Since the 1960s, four generations of these synthetic antibiotics have been created and successfully introduced into clinical practice. However, they are still of interest for medicinal chemistry due to the wide possibilities for chemical modification, with subsequent useful changes in the pharmacokinetics and pharmacodynamics of the initial molecules. This review summarizes the chemical and pharmacological results of fluoroquinolones hybridization by introducing different heterocyclic moieties into position 3 of the core system. It analyses the synthetic procedures and approaches to the formation of heterocycles from the fluoroquinolone carboxyl group and reveals the most convenient ways for such procedures. Further, the results of biological activity investigations for the obtained hybrid pharmacophore systems are presented. The latter revealed numerous promising molecules that can be further studied to overcome the problem of resistance to antibiotics, to find novel anticancer agents and more.

New promising levofloxacin derivatives: Design, synthesis, cytotoxic activity screening, Topo2β polymerase inhibition assay, cell cycle apoptosis profile analysis

Newly designed levofloxacin analogues were synthesized to act as topoisomerase II beta inhibitors (Topo2β). Their cytotoxic activity was screened against breast, liver, and leukemia cancer cell lines. The best activity against liver cancer cell line (Hep3B) was exhibited by the target compounds 3c, 3e, 4a, and 6d (IC₅₀ = 2.33, 1.38, 0.60 and 0.43, respectively). (L-SR) leukemia cancer cell line was pronouncedly affected by compounds 3b, 3g and 4a (IC₅₀ = 1.62, 1.41 and 1.61, sequentially). 3c possessed the best activity against breast cancer cell line (MCF-7) with IC₅₀ = 0.66. Compounds 3c, 3e, 3g, 4a and 4c exhibited Topo2β inhibition activities exceeding etoposide and levofloxacin as reference drugs and variant cell lines. In DNA-Flow cytometry cell cycle analysis, compound 3c arrested the cell cycle at G2/M phase like etoposide and levofloxacin, while compounds 3e and 4a exhibit its arrest at S phase. In addition, 3c, 3e and 4a showed a significant elevation in active caspase-3 levels (10.01, 8.98 and 10.71 folds, respectively). The effect of the new compounds on normal cells was also investigated including breast (MCF10a), liver (THLE2), and lymphocytic (PCS-800-011) normal cell lines.

Cytotoxic Properties of 1,3,4-Thiadiazole Derivatives-A Review

During recent years, small molecules containing five-member heterocyclic moieties have become the subject of considerable growing interest for designing new antitumor agents. One of them is 1,3,4-thiadiazole. This study is an attempt to collect the 1,3,4-thiadiazole and its derivatives, which can be considered as potential anticancer agents, reported in the literature in the last ten years.

Synthesis, evaluation of thymidine phosphorylase and angiogenic inhibitory potential of ciprofloxacin analogues: Repositioning of ciprofloxacin from antibiotic to future anticancer drugs

Over expression of thymidine phosphorylase (TP) in various human tumors compared to normal healthy tissue is associated with progression of cancer and proliferation. The 2-deoxy-d-ribose is the final product of thymidine phosphorylase (TP) catalyzed reaction. Both TP and 2-deoxy-d-ribose are known to promote unwanted angiogenesis in cancerous cells. Discovery of potent inhibitors of thymidine phosphorylase (TP) can offer appropriate approach in cancer treatment. A series of ciprofloxacin 2, 3a-3c, 4a-4d, 5a-5b, 6 and 7 has been synthesized and characterized using spectroscopic techniques. Afterwards, inhibitory potential of synthesized ciprofloxacin 2, 3a-3c, 4a-4d, 5a-5b, 6 and 7 against thymidine phosphorylase enzyme was assessed. Out of these twelve analogs of ciprofloxacin nine analogues 3a-3c, 4a-4c, 5a-5b and 6 showed good inhibitory activity against thymidine phosphorylase. Inhibitory activity as presented by their IC₅₀ values was found in the range of 39.71 ± 1.13 to 161.89 ± 0.95 μM. The 7-deazaxanthine was used as a standard inhibitor with IC₅₀ = 37.82 ± 0.93 μM. Furthermore, the chick chorionic allantoic membrane (CAM) assay was used to investigate anti-angiogenic activity of the most active ciprofloxacin-based inhibitor 3b. To enlighten the important binding interactions of ciprofloxacin derivatives with target enzyme, the structure activity relationship and molecular docking studies of chosen ciprofloxacin analogues was discussed. Docking studies revealed key π-π stacking, π-cation and hydrogen bonding interactions of ciprofloxacin analogues with active site residues of thymidine phosphorylase enzyme.

A comprehensive review of topoisomerase inhibitors as anticancer agents in the past decade

The topoisomerase enzymes play an important role in DNA metabolism, and searching for enzyme inhibitors is an important target in the search for new anticancer drugs. Discovery of new anticancer chemotherapeutical capable of inhibiting topoisomerase enzymes is highlighted in anticancer research. Therefore, biologists, organic chemists and medicinal chemists all around the world have been identifying, designing, synthesizing and evaluating a variety of novel bioactive molecules targeting topoisomerase. This review summarizes types of topoisomerase inhibitors in the past decade, and divides them into nine classes by structural characteristics, including N-heterocycles compounds, quinone derivatives, flavonoids derivatives, coumarin derivatives, lignan derivatives, polyphenol derivatives, diterpenes derivatives, fatty acids derivatives, and metal complexes. Then we discussed the application prospect and development of these anticancer compounds, as well as concluded parts of their structural-activity relationships. We believe this review would be invaluable in helping to further search potential topoisomerase inhibition as antitumor agent in clinical usage.

Synthesis, Characterization, and Biological Activity of a Novel Series of Benzo[4,5]imidazo[2,1-b]thiazole Derivatives as Potential Epidermal Growth Factor Receptor Inhibitors

Based on the analysis of epidermal growth factor receptor (EGFR) complexes with gefitinib with molecular docking, the scaffold-hopping strategy, combination of the active substructures, and structural optimization of EGFR inhibitors, a novel series of benzo[4,5]imidazo[2,1-b]thiazole derivatives was designed, synthesized, and evaluated for antitumor activity in human cancer cell lines and cellular toxicity against human normal cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay and EGFR inhibitory activities in vitro. Some target compounds such as 2-(benzo[4,5]imidazo[2,1-b]thiazol-3-yl)-N-(2-hydroxyphenyl)acetamide (D04) and 2-(benzo[4,5]imidazo[2,1-b]thiazol-3-yl)-N-(naphthalen-1-yl)acetamide (D08) have shown significant antitumor activity against the EGFR high-expressed human cell line HeLa. All the target compounds showed hardly any antitumor activity against the EGFR low-expressed human cell line HepG2, and nearly no cellular toxicity against the human normal cell lines HL7702 and human umbilical vein endothelial cell lines (HUVEC). The inhibitory activities against EGFR kinase in vitro of the three target compounds were greatly consistent with the anti-proliferative activities. The preliminary structure⁻activity relationships of the target compounds were summarized. Conclusively, the novel benzo[4,5]imidazo[2,1-b]thiazole derivatives as novel potential EGFR inhibitors may be used as the potential lead compounds for the development of antitumor agents.

Repositioning of fluoroquinolones from antibiotic to anti-cancer agents: An underestimated truth

Increasing development costs and higher failure rate in clinical trials has reduced the repertoire of newer drugs in the market for clinical use. The most appropriate approach to end the search for newer drugs is "Repositioning", as it requires less time and money to explore new indication of existing drug or failed drug. In the past, several drugs have been repositioned for different indication but the full potential remains unharnessed. With rise in cancer prevalence and treatment costs, it is imperative to search for newer drugs and the use of repositioning approach may help us. Fluoroquinolones has been used as antibiotics for over four decades now, but recent research highlighted their use as pharmacological compounds with multifaceted implication. Repositioning of fluoroquinolones into anti-cancer molecule seems to be a highly plausible option owing to their profound immunomodulatory, pro-apoptotic, anti-proliferative and anti-metastatic potential. The present review provides a comprehensive account of the recent and past explorations pertaining to the anti-cancer activity of fluoroquinolones and also discusses the various approaches that are being considered to remodel them for the treatment of cancer.

Modifications of quinolones and fluoroquinolones: hybrid compounds and dual-action molecules

ABSTRACT

This review is aimed to provide extensive survey of quinolones and fluoroquinolones for a variety of applications ranging from metal complexes and nanoparticle development to hybrid conjugates with therapeutic uses. The review covers the literature from the past 10 years with emphasis placed on new applications and mechanisms of pharmacological action of quinolone derivatives. The following are considered: metal complexes, nanoparticles and nanodrugs, polymers, proteins and peptides, NO donors and analogs, anionic compounds, siderophores, phosphonates, and prodrugs with enhanced lipophilicity, phototherapeutics, fluorescent compounds, triazoles, hybrid drugs, bis-quinolones, and other modifications. This review provides a comprehensive resource, summarizing a broad range of important quinolone applications with great utility as a resource concerning both chemical modifications and also novel hybrid bifunctional therapeutic agents.

GRAPHICAL ABSTRACT

Synthesis and biological evaluation of sophoridinol derivatives as a novel family of potential anticancer agents

New N-substituted sophoridinic acid/ester and sophoridinol derivatives were synthesized and evaluated for their cytotoxic activity in human HepG2 hepatoma cells from the lead sophoridine (1). Among the newly synthesized compounds, sophoridinol 7i displayed a potential antiproliferative activity with an IC50 of 3.1 μM. Importantly, it exerted an almost equipotent effect against both wild MCF-7 and adriamycin (AMD)-resistant MCF-7 (MCF-7/AMD) breast carcinoma cell lines. Its mode of action was to arrest the cell cycle at the G0/G1 phase, consistent with that of the parent 1. In addition, compound 7i also showed a reasonable ClogP value and favorable pharmacokinetic property with an area under the concentration-time curve (AUC) of 10.3 μM·h in rats, indicating an ideal druggable characteristic. We consider sophoridinol derivatives to be a novel family of promising antitumor agents with an advantage of inhibiting drug-resistant cancer cells.