Development of New Potential Anticancer Metal Complexes Derived from 2-Hydrazinobenzothiazole

New thiazole derivative as a potential anticancer and topoisomerase II inhibitor

To shed light on the significance of thiazole derivatives in the advancement of cancer medication and to contribute to therapeutic innovation, we have designed the synthesis and antiproliferative activity investigation of 5-(1,3-dioxoisoindolin-2-yl)-7-(4-nitrophenyl)-2-thioxo-3,7-dihydro-2H-pyrano[2,3-d] thiazole-6-carbonitrile, the structure of thiazole derivative was confirmed by spectroscopic techniques UV, IR and NMR. The cytotoxic activity (in vitro) of the new hybrid synthesized compound on five human cancer cell lines; human liver hepatocellular carcinoma (HepG-2), colorectal carcinoma (HCT-116), breast adenocarcinoma (MCF-7), and epithelioid carcinoma (Hela), and a normal human lung fibroblast (WI-38) was studied using MTT assay. The compound exhibited a strong cytotoxicity effect against HepG-2 and MCF-7. The interaction of the newly synthesized compound with calf-thymus DNA (CT-DNA) was investigated at pH 7.2 by using UV-Vis absorption measurements, also, molecular docking was carried out to investigate the DNA binding affinity of the proposed compound with the prospective target, DNA (PDB ID: 1d12). Finally, molecular docking was carried out to examine the binding patterns with the prospective target, DNA-Topo II complex (PDB-code: 3QX3). Results indicated that the investigated compound strongly binds to CT-DNA via intercalative mode, and correlated with those obtained from molecular docking and in agreement with that of in vitro cytotoxicity activity.

Synergistic impacts of rifampicin and doxorubicin against thioacetamide-induced hepatocellular carcinoma in rats

Background and aims

Combination therapy is a promising new strategy that has been proposed to increase the efficacy of cancer treatment. We aimed to investigate the anti-cancer activity of rifampicin monotherapy and its combination with doxorubicin against hepatocellular carcinoma (HCC).

Materials and methods

The in vitro half maximal inhibitory concentration (IC50) and selectivity index (SI) of the drugs under investigation against HepG2 and human lung fibroblast (WI38) cell lines were determined. For the in vivo experiment, male Sprague-Dawley albino rats were injected with thioacetamide at 200 mg/kg twice a week for 90 days; HCC development was confirmed histopathologically. Following HCC induction, the rats were treated with intraperitoneal doxorubicin, rifampicin, or their combination for 45 or 90 days. After sacrifice, the livers were examined histopathologically. The levels of aminotransferases, albumin, bilirubin, malondialdehyde, superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC), and nitric oxide were measured by spectrophotometry. Alpha-fetoprotein, cancer antigen 19-9, tumor necrosis factor-alpha, interleukin-6, Bcl-2-associated X protein, caspase 3, caspase 8, and p53 were estimated using ELISA.

Results

In vitro, the combination of doxorubicin and rifampicin showed the highest SI of 3.43. In vivo, among the measured markers, the levels of TAC, CAT, SOD, and p53 decreased (P < 0.001) and the rest of the measured marker levels increased (P < 0.001) in the HCC-bearing rats; after treatment in all groups, all these changes improved toward normal in a time-dependent manner. The combination of doxorubicin and rifampicin optimized the effects of the two individual drugs and exerted the best antioxidant effects.

Conclusions

In general, compared with rifampicin or doxorubicin alone, combination therapy has favorable outcomes. Based on our results, the combination of rifampicin and doxorubicin might be applicable for HCC chemotherapy.

2-Aminobenzothiazoles in anticancer drug design and discovery

Cancer is one of the major causes of mortality and morbidity worldwide. Substantial research efforts have been made to develop new chemical entities with improved anticancer efficacy. 2-Aminobenzothiazole is an important class of heterocycles containing one sulfur and two nitrogen atoms, which is associated with a broad spectrum of medical and pharmacological activities, including antitumor, antibacterial, antimalarial, anti-inflammatory, and antiviral activities. In recent years, an extraordinary collection of potent and low-toxicity 2-aminobenzothiazole compounds have been discovered as new anticancer agents. Herein, we provide a comprehensive review of this class of compounds based on their activities against tumor-related proteins, including tyrosine kinases (CSF1R, EGFR, VEGFR-2, FAK, and MET), serine/threonine kinases (Aurora, CDK, CK, RAF, and DYRK2), PI3K kinase, BCL-XL, HSP90, mutant p53 protein, DNA topoisomerase, HDAC, NSD1, LSD1, FTO, mPGES-1, SCD, hCA IX/XII, and CXCR. In addition, the anticancer potentials of 2-aminobenzothiazole-derived chelators and metal complexes are also described here. Moreover, the design strategies, mechanism of actions, structure-activity relationships (SAR) and more advanced stages of pre-clinical development of 2-aminobenzothiazoles as new anticancer agents are extensively reviewed in this article. Finally, the examples that 2-aminobenzothiazoles showcase an advantage over other heterocyclic systems are also highlighted.

Biochemical and pathophysiological improvements in rats with thioacetamide induced-hepatocellular carcinoma using aspirin plus vitamin C

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death, so we should be concerned and look for effective/less-harmful treatments than chemotherapeutics already clinically in application. Aspirin works well ''in conjunction'' with other therapies for HCC since aspirin can boost the sensitivity of anti-cancer activity. Vitamin C also was shown to have antitumor effects. In this study, we examined the anti-HCC activities of synergistic combination (aspirin and vitamin C) vs. doxorubicin on HCC-bearing rats and hepatocellular carcinoma (HepG-2) cells.

METHODS

In vitro, we evaluated IC₅₀ and selectivity index (SI) using HepG-2 and human lung fibroblast (WI-38) cell lines. In vivo, four rat groups were used: Normal, HCC (intraperitoneally (i.p.) administered 200 mg thioacetamide/kg/twice a week), HCC + DOXO (HCC-bearing rats i.p. administered 0.72 mg doxorubicin (DOXO)/rat/once a week), and HCC + Aspirin + Vit. C (i.p. administered vitamin C (Vit. C) 4 g/kg/day after day concomitant with aspirin 60 mg/kg/orally day after day). We evaluated biochemical factors [aminotransferases (ALT and AST), albumin, and bilirubin (TBIL) spectrophotometrically, caspase 8 (CASP8), p53, Bcl2 associated X protein (BAX), caspase 3 (CASP3), alpha-fetoprotein (AFP), cancer antigen 19.9 (CA19.9), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) using ELISA], and liver histopathologically.

RESULTS

HCC induction was accompanied by significant time-dependent elevations in all measured biochemical parameters except the p53 level significantly declined. Liver tissue architecture organization appeared disturbed with cellular infiltration, trabeculae, fibrosis, and neovascularization. Following drug medication, all biochemical levels significantly reversed toward normal, with fewer signs of carcinogenicity in liver tissues. Compared to doxorubicin, aspirin & vitamin C therapy ameliorations were more appreciated. In vitro, combination therapy (aspirin & vitamin C) exhibited potent cytotoxicity (HepG-2 IC₅₀ of 17.41 ± 1.4 µg/mL) and more excellent safety with a SI of 3.663.

CONCLUSIONS

Based on our results, aspirin plus vitamin C can be considered reliable, accessible, and efficient synergistic anti-HCC medication.

Anticancer effect evaluation of iridium(III) complexes targeting mitochondria and endoplasmic reticulum

Ligand HMSPIP (2-(4-(methylsulfonyl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) and its iridium(III) complexes [Ir(ppy)₂(HMSPIP)]PF₆ (ppy = 2-phenylpyridine, Ir1) and [Ir(bzq)₂(HMSPIP)]PF₆ (bzq = benzo[h]quinoline, Ir2) were synthesized. The complexes were characterized by ¹H NMR, ¹³C NMR, and UV/Vis spectra. The cytotoxicity of the complexes toward cancer cells were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method, the scratch wound healing and colony-forming were also investigated. MTT assay certificated that the complexes show high toxic effect on the HeLa cells. The cell cycle assay illustrated that the complexes blocked cell growth at G₀/G₁ phase in HeLa cells. A series of subsequent experiments showed that the complexes first enter the endoplasmic reticulum (ER) and then enter the mitochondria, leading to an increase in intracellular Ca²⁺ and reactive oxygen species (ROS) content, depolarizing mitochondrial membrane potential (MMP), and ultimately resulting in apoptosis. In addition, the experimental results revealed that the complexes not only increase the level of ROS but also inhibit the production of GSH and eventually produce large amounts of MDA and further leading to cell death. Taken together, we consider that the complexes can be used as potential candidate drugs for HeLa cancer treatment.

1,4-Naphthoquinone Motif in the Synthesis of New Thiopyrano[2,3-d]thiazoles as Potential Biologically Active Compounds

A series of 11-substituted 3,5,10,11-tetrahydro-2H-benzo[6,7]thiochromeno[2,3-d][1,3]thiazole-2,5,10-triones were obtained via hetero-Diels-Alder reaction of 5-alkyl/arylallylidene/-4-thioxo-2-thiazolidinones and 1,4-naphthoquinones. The structures of newly synthesized compounds were established by spectral data and a single-crystal X-ray diffraction analysis. According to U.S. NCI protocols, compounds 3.5 and 3.6 were screened for their anticancer activity; 11-Phenethyl-3,11-dihydro-2H-benzo[6,7]thiochromeno[2,3-d]thiazole-2,5,10-trione (3.6) showed pronounced cytotoxic effect on leukemia (Jurkat, THP-1), epidermoid (KB3-1, KBC-1), and colon (HCT116wt, HCT116 p53-/-) cell lines. The cytotoxic action of 3.6 on p53-deficient colon carcinoma cells was two times weaker than on HCT116wt, and it may be an interesting feature of the mechanism action.

Response of Ancillary Azide Ligand in Designing a 1D Copper(II) Polymeric Complex along with the Introduction of High DNA- and HAS-Binding Efficacy, Leading to Impressive Anticancer Activity: A Compact Experimental and Theoretical Approach

A new versatile azide-bridged polymeric Cu(II) complex, namely, [Cu(L)(μ_1,3-N₃)]_∞ (1), was synthesized utilizing an N,N,O-donor piperidine-based Schiff base ligand (E)-4-bromo-2-((2-(-1-yl)imino)methyl)phenol (HL), obtained via the condensation reaction of 1-(2-aminoethyl) piperidine and 5-bromo salicylaldehyde. The single-crystal X-ray diffraction analysis reveals that complex 1 consists of an end-to-end azido-bridged polymeric network, which is further rationalized with the help of a density functional theory (DFT) study. After routine characterization with a range of physicochemical studies, complex 1 is exploited to evaluate its biomedical potential. Initially, theoretical inspection with the help of a molecular docking study indicated the ability of complex 1 to effectively bind with macromolecules such as DNA and the human serum albumin (HSA) protein. The theoretical aspect was further verified by adopting several spectroscopic techniques. The electronic absorption spectroscopic analysis indicates a remarkable binding efficiency of Complex 1 with both DNA and HSA. The notable fluorescence intensity reduction of the ethidium bromide (EtBr)-DNA adduct, 4',6-diamidino-2-phenylindole (DAPI)-DNA adduct, and HSA after the gradual addition of complex 1 authenticates its promising binding potential with the macromolecules. The retention of the canonical B form of DNA and α form of HSA during the association of complex 1 was confirmed by implementing a circular dichroism spectral study. The association ability of complex 1 with macromolecules further inspired us to inspect its impact on different cell lines such as HeLa (cervical cancer cell), PA1 (ovarian cancer cell), and HEK (normal cell). The dose-dependent and time-dependent in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay suggests an effective antiproliferative property of complex 1 with low toxicity toward the normal cell line. Finally, the anticancer activity of complex 1 toward carcinoma cell lines was analyzed by nuclear and cellular staining techniques, unveiling the cell death mechanism.

A Newly Synthesized Derivative and a Natural Parent Molecule: Which Would Be More Beneficial as a Future Antitumor Candidate? Docking and In Vivo Study

Seeking for new effectual anticancer drugs is of great importance. In this study, a newly synthesized and well-characterized chromene derivative (ethyl 2-amino-4-phenyl-4H-benzo(h)chromene-3-carboxylate) "C" was prepared. Molecular docking studies were done. The new compound "C" in compare to the natural parent Quercetin "Q," as a well-known natural chromene derivative with antioxidant and antitumor activities, were tested for their antitumor activity against Ehrlich ascites carcinoma (EAC)-bearing mice. Both reduced ascites volume, decreased viable EAC cells, and prolonged EAC-bearing mice life span. They normalized troponin, creatine kinase-MB, lactate dehydrogenase, and urea levels, reversed liver enzyme activities towards normal, and increased antioxidant levels while reduced tumor necrosis factor-alpha (TNF-α) levels. Compared to each other, the new synthetic derivative "C" showed stronger antineoplastic effects than the natural parent "Q" may via the anti-inflammatory activities. Therefore, the newly synthesized chromene derivative is more promising as a future antitumor candidate than the natural parent molecule "Quercetin." Finally, our results encourage researchers to pay more attention to developing more novel natural-based derivatives that would be more beneficial as future therapeutics than their natural parents.

Palladium(II) Schiff base complex arrests cell cycle at early stages, induces apoptosis, and reduces Ehrlich solid tumor burden: a new candidate for tumor therapy

Although many cancer drugs are clinically approved, they still suffer from no adequate efficiency or drug resistance, or bad side effects. Therefore, developing safer alternatives of competitive efficiency is needed. This study aimed to investigate, for the first time, the antitumor and apoptotic activities of palladium(II) 2-hydroxyimino-3-(2-hydrazonopyridyl)-butane complex against Ehrlich carcinoma. In vitro, EAC cells were incubated with the complex, and the cells' viability, caspase 8 activity, and cell cycle changes were evaluated. In vivo, eighty adult female Swiss albino mice were distributed randomly in the following groups (n = 10): Normal, EAC, EAC + Cisplatin, and four groups EAC + Complex as well as Normal + Complex. Bodyweight changes were noted. On day 22 mice were sacrificed. Tumors' volume and weight were recorded. Blood picture was routinely investigated. The median survival time (MST) and percent increase in life span (%ILS) were monitored. In vitro, the complex reduced the %viable EAC cells, increased caspase 8 activity, arrested cell cycle at G0/G1, and reduced G2(M) population indicating antiproliferative and antitumor activities via inducing apoptosis. Treatment with the complex in a dose-dependent mode significantly decreased tumor volume and weight, extended the MST and the %ILS, increased mice body weight gain, and improved the blood indexes. Treatment of EAC-bearing mice with the complex highest dose showed more desirable outcomes than treatment with cisplatin. The Normal + Complex group showed no pathological changes indicating safety. In conclusion, our outcomes recommend the Pd(II) complex as a new optimistic candidate for tumor therapy after further studies for validation.

Schiff base 4-ethyl-1-(pyridin-2-yl) thiosemicarbazide up-regulates the antioxidant status and inhibits the progression of Ehrlich solid tumor in mice

Cisplatin is an approved cancer therapeutic drug used to treat many solid tumors but its accumulation in the kidney, which causes nephrotoxicity, limits its clinical use. Therefore, investigators seek new alternatives to cisplatin that may be more effective and/or safer. Thiosemicarbazides are of great significance due to their expected biological activity including anticancer activities. The aim of this work is the study of the antitumor effect of Schiff base 4-ethyl-1-(pyridin-2-yl) thiosemicarbazide (HEPTS) on Ehrlich solid tumor-bearing mice in comparison to cancer therapeutic drug cisplatin. The experiment was run using sixty adult female Swiss albino mice. Mice were allocated into six groups (n = 10 mice). Healthy control, EAC control (untreated tumor), EAC + cisplatin, EAC + HEPTS, Healthy + HEPTS, and Healthy + solvent. After scarification, blood samples, liver organs, and solid tumors were collected. Tumor weights and volumes were registered. The concentrations of malondialdehyde (MDA), reduced glutathione (GSH), SOD, catalase (CAT), total antioxidant capacity (TAC), nitric oxide (NO), uric acid, creatinine, and urea were assessed. Median survival time (MST) and the percentage increase in lifespan (%ILS) were also calculated. Treatment of tumorized mice with HEPTS significantly reduced both tumor volume and weight while it significantly increased the MST, antioxidant marks and prolonged the %ILS. It also, significantly reduced MAD, creatinine, urea, uric acid, and NO levels. Compared to cisplatin, HEPTS effects were better. Our results recommend HEPTS as one of the probable cisplatin-alternatives for tumor treatment after more validation.

Aryl variation and anion effect on CT-DNA binding and in vitro biological studies of pyridinyl Ag(I) complexes

Synthesis and spectroscopic characterization of five ligands ((E)-2-((pyridin-2-ylmethylene)amino)phenol L1, 2-(pyridin-2-yl)benzo[d]thiazole L2, (E)-N-(2-fluorophenyl)-1-(pyridin-2-yl)methanimine L3, (E)-1-(pyridin-2-yl)-N-(p-tolyl)methanimine L4 and (E)-1-(pyridin-2-yl)-N-(thiophen-2-ylmethyl)methanimine L5 along with fifteen silver(I) complexes of L1 - L5, with a general formula [AgL₂]⁺X^- (L = Schiff base and X = NO₃^-, ClO₄^- or CF₃SO₃^-) is reported. The structures of complexes [Ag(L4)₂]NO₃, [Ag(L5)₂]NO₃, [Ag(L3)₂]ClO₄, [Ag(L4)₂]ClO₄ and [Ag(L5)₂]CF₃SO₃ were determined unequivocally by single crystal X-ray diffraction analysis. Calf-thymus deoxyribonucleic acid (CT-DNA), bovine serum albumin (BSA) binding studies, antioxidant, and antibacterial studies were performed for all complexes. Complexes [Ag(L2)₂]NO₃, [Ag(L5)₂]NO₃, [Ag(L1)₂]ClO₄ and [Ag(L3)₂]ClO₄ whose ligands have an OH^- and F^- as substituents or with a thiophene or thiazole moiety showed better antibacterial activities with lower minimum inhibitory concentration (MIC) values compared to the standard ciprofloxacin, against most of the bacterial strains tested. Similarly, complexes [Ag(L1)₂]NO_3,[Ag(L2)₂]NO_3,[Ag(L3)₂]NO₃ and [Ag(L5)₂]NO₃ with the NO₃^- anion, [Ag(L1)₂]ClO₄ and [Ag(L2)₂]ClO₄ with ClO₄^- anion, and [Ag(L5)₂]CF₃SO₃ with CF₃SO₃^- anion showed higher activities for antioxidant studies. Complexes [Ag(L4)₂]ClO₄ and [Ag(L4)₂]CF₃SO₃ with the Methyl substituent and CF₃SO₃^- as the anion, displayed high antioxidant activities in FRAP (ferric reducing antioxidant power) than the standard ascorbic acid. Spectroscopic studies of all the complexes revealed their moderate to high interaction with calf thymus DNA via an intercalation mode. In addition, the relatively moderate interaction of most of the complexes with BSA was through a static quenching mechanism.

Loading of some quinoxaline derivatives in poly (l-lactic) acid/Pluronic® F-127 nanofibers enhances their anticancer efficiency and induces a p53 and p21 apoptotic-signaling pathway

The objective of this study was to evaluate the anticancer activity on cancer cell models of a drug delivery system consisting of poly (l-lactic) acid/Pluronic® F-127 (PLLA/PF127) loaded with the new N-butylpyridoquinoxaline 1,4-dioxide (NBPQD) or 2-amino-3-cyano-6-methylquinoxaline 1,4-dioxide (ACMQD) that was synthesized using an electrospinning process compared to free NBPQD and ACMQD. PLLA/PF127-NBPQD and PLLA/PF127-ACMQD nanofibers were prepared, and their shape, size, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric (TGA) analysis, water contact angel (WCA), drug release, anticancer activity against five human cancer cell lines, and flowcytometeric analyses of cell cycle, p21 and p53 activities were investigated. PLLA/PF127 nanofibers with NBPQD or ACMQD were smooth, and no NBPQD or ACMQD clusters were found on nanofibers surface. FTIR analysis indicated that intermolecular hydrogen bonding between NBPQD or ACMQD and the polymer matrix is present. PLLA/PF127 nanofibers with NBPQD or ACMQD showed quite stable thermal stability with degradation at about 400 °C, and showed high WCA values of 68.72 ± 3.83° and 110.59 ± 0.21°, respectively. They showed higher in vitro anticancer activity towards all investigated cell lines compared to free NBPQD or free ACMQD. The lowest IC₅₀ value for PLLA/PF127-NBPQD was 1.7 μg/ml with colorectal carcinoma (HCT-116) and was 4.5 μg/ml for PLLA/PF127-ACMQD with hepatocellular carcinoma (HepG2). PLLA/PF127 nanofibers with NBPQD or ACMQD increased anticancer efficiency via inducing cancer cell apoptosis through activation of a p53 and p21 apoptotic-signaling pathway.