Cytotoxic 2-benzylidene-6-(nitrobenzylidene)cyclohexanones which display substantially greater toxicity for neoplasms than non-malignant cells

Various 2-benzylidene-6-(nitrobenzylidene)cyclohexanones were prepared as candidate cytotoxins in which the nitro group was located in the ortho, meta and para positions leading to series 1–3, respectively. The CC₅₀ values towards human HSC-2 and HSC-4 oral squamous cell carcinomas as well as human HL-60 promyelocytic leukemic cells are in the low micromolar range in general. On the other hand, most of the compounds afforded clear evidence of being far less toxic towards human HGF gingival fibroblasts, HPC pulp cells and HPLF periodontal ligament fibroblasts which are non-malignant cells. Selectivity index (SI) figures were generated which are the ratios of the average CC₅₀ values towards normal cells and the CC₅₀ figure towards a malignant cell line. Huge SI values were obtained for many of the compounds. In particular 1c, 2f, 3c and 3g which have average SI values of >76, >38, 124 and 341, respectively, are clearly lead molecules affording direction for amplification of this area of study. A lead compound 1c caused internucleosomal DNA fragmentation and activation of caspase-3 in HL-60 cells but not in HSC-2 carcinomas. In a short-term toxicity study, doses up to and including 300 mg/kg of the majority of the compounds prepared in this study did not cause any mortalities to mice. Some guidelines for development of these tumor-selective cytotoxins are presented.     

Tumour-specific cytotoxicity and structure–activity relationships of novel 1-[3-(2-methoxyethylthio)propionyl]-3,5-bis(benzylidene)-4-piperidones

A series of 1-acyl-3,5-bis(benzylidene)-4-piperidones 3–7 were designed and synthesized as novel cytotoxic agents. These compounds displayed potent cytotoxic properties towards human Molt4/C8, CEM, HSC-2, HSC-3 and HSC-4 neoplasms and also to murine L1210 cells. The majority of the compounds have sub-micromolar or very low micromolar IC₅₀ and CC₅₀ values and are significantly more potent than the reference alkylating drug melphalan. Evaluation of these compounds against non-malignant HGF and HPLF cells revealed the tumour-specific toxicity. In particular, 3e emerged as a promising lead cytotoxic agent which caused apoptosis and PARP1 cleavage in HSC-2 cells.     

Synthesis of mono Mannich bases of 2-(4-hydroxybenzylidene)-2,3-dihydroinden-1-one and evaluation of their cytotoxicities

Chalcones and Mannich bases are a group of compounds known for their cytotoxicities. In this study restricted chalcone analogue, compound 2-(4-hydroxybenzylidene)-2,3-dihydroinden-1-one MT1, was used as a starting compound to synthesize new mono Mannich bases since Mannich bases may induce more cytotoxicity than chalcone analogue that they are derived from by producing additional alkylating center for cellular thiols. In this study, cyclic and acyclic amines were used to synthesize Mannich bases. All compounds were tested against Ca9–22 (gingival carcinoma), HSC-2, HSC-3 and HSC-4 (oral squamous cell carcinoma) as tumour cell lines and HGF (gingival fibroblasts), HPC (pulp cells) and HPLF (periodontal ligament fibroblasts) human normal oral cells as non tumour cell lines. Cytotoxicity, selectivity index (SI) values and potency selectivity expression (PSE) values expressed as a percentage were determined for the compounds. According to data obtained, the compound MT8 with the highest PSE value bearing N-methylpiperazine moiety seems to be a good candidate to develop new cytotoxic compounds and is suited for further investigation.     

2-(3-Aryl-2-propenoyl)-3-methylquinoxaline-1,4-dioxides: A novel cluster of tumor-specific cytotoxins which reverse multidrug resistance

A series of 2-(3-aryl-2-propenoyl)-3-methylquinoxaline-1,4-dioxides 3a–l were prepared by condensation of various aryl aldehydes with 2-acetyl-3-methylquinoxaline-1,4-dioxide 2. These compounds inhibit the growth of human Molt 4/C8 and CEM T-lymphocytes and the IC₅₀ values are mainly in the 5–30 μM range. The quinoxaline 1,4-dioxide 3j inhibited the growth of 58 human tumor cell lines, particularly leukemic and breast cancer neoplasms. All of the compounds 3a–l reversed the multidrug resistance (MDR) properties of murine L-5178Y leukemic cells which were transfected with the human MDR1 gene. The MDR-reversing effect may be due to the conjugated π-electron system forming a weak electron charge transfer complex with the P-glycoprotein-mediated efflux pump. The compounds in series 2 and 3 were assessed against HL-60, HSC-2, HSC-3 and HSC-4 malignant cells as well as HGF, HPC and HPLF normal cell lines which revealed that the majority of the compounds displayed a greater toxicity to neoplastic than normal cells. Various ways in which the project may be expanded are presented.     

Synthesis of some acrylophenones with N-methylpiperazine and evaluation of their cytotoxicities

In this study, the compounds having acrylophenone structure, 1-aryl-2-(N-methylpiperazinomethyl)-2-propen-1-one dihydrochlorides, were synthesized and their chemical structures were identified with ¹H NMR, ¹³C NMR and HRMS spectra. The cytotoxicities of the compounds were tested towards Ca9-22 (human gingival carcinoma), HSC-2 (human oral squamous carcinoma), HSC-3 (human oral squamous carcinoma) and HSC-4 (human oral squamous carcinoma) cell lines as tumor cell lines and HGF (gingival fibroblasts), HPLF (periodontal ligament fibroblasts) and HPC (pulp cells) cell lines as non-tumor cell lines. PSE of the compound TA2, which has a methyl substituent on phenyl ring, pointed out the compound TA2 as a leader compound to be considered.     

Synthesis and bioactivities of pyrazoline benzensulfonamides as carbonic anhydrase and acetylcholinesterase inhibitors with low cytotoxicity

4-(3-Substitutedphenyl-5-polymethoxyphenyl-4,5-dihydro-1H-pyrazol-1-yl)benzenesulfonamides (9–16) were synthesized and their chemical structures were elucidated by ¹H NMR, ¹³C NMR, and HRMS. The compounds designed include pyrazoline and sulfonamide pharmacophores in a single molecule by hibrit molecule approach which is a useful technique in medicinal chemistry in designing new compounds with potent activity for the desired several bioactivities. Inhibition potency of the sulfonamides were evaluated against human CA isoenzymes (hCA I and hCA II) and acetylcholinesterase (AChE) enzyme and also their cytotoxicities were investigated towards oral squamous cancer cell carcinoma (OSCC) cell lines (Ca9-22, HSC-2, HSC-3, and HSC-4) and non-tumor cells (HGF, HPLF, and HPC). Cytosolic hCA I and hCA II isoenzymes were inhibited by the sulfonamide derivatives (9–16) and Ki values were found in the range of 27.9 ± 3.2–74.3 ± 28.9 nM and 27.4 ± 1.4–54.5 ± 11.6 nM, respectively. AChE enzyme was strongly inhibited by the sulfonamide derivatives with Ki values in the range of 37.7 ± 14.4–89.2 ± 30.2 nM The CC₅₀ values of the compounds were found between 15 and 200 µM towards OSCC malign cell lines. Their tumor selectivities were also calculated with two ways. Compound’s selectivities towards cancer cell line were found generally low, except compounds bearing 3,4-dimethoxyphenyl 14 (TS1 = 1.3, TS2 = 1.4) and 10 (TS2 = 1.4). All sulfonamide derivatives studied here can be considered as good candidates to develop novel CAs or AChE inhibitor candidates based on the enzyme inhibition potencies with their low cytotoxicity and tumor selectivity.     

Synthesis,biological evaluation and in silico modelling studies of 1,3,5-trisubstituted pyrazoles carrying benzenesulfonamide as potential anticancer agents and selective cancer-associated hCA IX isoenzyme inhibitors

Inhibition of carbonic anhydrases (CAs, EC 4.2.1.1) has clinical importance for the treatment of several diseases. They participate in crucial regulatory mechanisms for balancing intracellular and extracellular pH of the cells. Among CA isoforms, selective inhibition of hCA IX has been linked to decreasing of cell growth for both primary tumors and metastases. The discovery of novel CA inhibitors as anticancer drug candidates is a current topic in medicinal chemistry. 1,3,5-Trisubstituted pyrazoles carrying benzenesulfonamide were evaluated against physiologically abundant cytosolic hCA I and hCA II and trans-membrane, tumor-associated hCA IX isoforms by a stopped-flow CO₂ hydrase method. Their in vitro cytotoxicities were screened against human oral squamous cell carcinoma (OSCC) cell lines (HSC-2) and human mesenchymal normal oral cells (HGF) via 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) test. Compounds 6, 8, 9, 11, and 12 showed low nanomolar hCA II inhibitory potency with Ki < 10 nM, whereas compounds 9 and 12 displayed Ki < 10 nM against hCA IX isoenzyme when compared with reference Acetazolamide (AZA). Compound 9, 4-(3-(hydrazinecarbonyl)-5-(4-nitrophenyl)-1H-pyrazol-1-yl)benzenesulfonamide, can be considered as the most selective hCA IX inhibitor over off-target cytosolic isoenzymes hCA I and hCA II with the lowest Ki value of 2.3 nM and selectivity ratios of 3217 (hCA I/hCA IX) and 3.9 (hCA II/hCA IX). Isoform selectivity profiles were also discussed using in silico modelling. Cytotoxicity results pointed out that compounds 5 (CC₅₀ = 37.7 μM) and 11 (CC₅₀ = 58.1 μM) can be considered as lead cytotoxic compounds since they were more cytotoxic than 5-Fluorouracil (5-FU) and Methotrexate (MTX).     

Synthesis and biological evaluation of novel 2-(substituted phenylaminocarbonylmethylthio)-6-(2,6-dichlorobenzyl)-pyrimidin-4(3H)-ones as potent HIV-1 NNRTIs

A series of novel 2-(phenylaminocarbonylmethylthio)-6-(2,6-dichlorobenzyl)-pyrimidin-4(3H)-ones have been designed and synthesized. All of the new compounds were evaluated for their anti-HIV activities in MT-4 cells. Most of these new compounds showed moderate to potent activities against wild-type HIV-1 with an EC₅₀ ranging from 4.48 μM to 0.18 μM. Among them, 2-[(4-bromophenylamino)carbonylmethylthio]-6-(2,6-dichlorobenzyl)-5-methylpyrimidin-4(3H)-one 4b3 was identified as the most promising compound (EC₅₀ = 0.18 ± 0.06 μM, CC₅₀ >243.56 μM, SI >1326). The structure–activity relationship (SAR) of these new congeners is discussed.     

SYNTHESIS OF UNNATURAL 7-SUBSTITUTED-1-(2-DEOXY-β-D-RIBOFURANOSYL)ISOCARBOSTYRILS†: “THYMINE REPLACEMENT” ANALOGS OF DEOXYTHYMIDINE FOR EVALUATION AS ANTIVIRAL AND ANTICANCER AGENTS

A group of unnatural 1-(2-deoxy-β-D-ribofuranosyl)isocarbostyrils having a variety of C-7 substituents [H, 4,7-(NO₂)₂, I, CF₃, CN, (E)-CH=CH-I, -C═CH, -C═C-I, -C═C-Br, -C═C-Me], designed as nucleoside mimics, were synthesized for evaluation as anticancer and antiviral agents. This class of compounds exhibited weak cytotoxicity in a MTT assay (CC₅₀=10^?3 to 10^?5 M range) with the 4,7-dinitro derivative being the most cytotoxic, relative to thymidine (CC₅₀=10^?3 to 10^?5 M range), against a variety of cancer cell lines. The 4,7-dinitro, 7-I and 7-C═CH compounds exhibited similar cytotoxicity against non-transfected (KBALB, 143B), and HSV-1 TK⁺ gene transfected (KBALB-STK, 143B-LTK) cancer cell lines possessing the herpes simplex virus type 1 (HSV-1) thymidine kinase gene (TK⁺). This observation indicates that these compounds are not substrates for HSV type-1 TK, and are therefore unlikely to be useful in gene therapy based on the HSV gene therapy paradigm.

     

Detection of high PD-L1 expression in oral cancers by a novel monoclonal antibody L1Mab-4

Programmed cell death-ligand 1 (PD-L1), which is a ligand of programmed cell death-1 (PD-1), is a type I transmembrane glycoprotein that is expressed on antigen-presenting cells and several tumor cells, including melanoma and lung cancer cells. There is a strong correlation between human PD-L1 (hPD-L1) expression on tumor cells and negative prognosis in cancer patients. In this study, we produced a novel anti-hPD-L1 monoclonal antibody (mAb), L₁Mab-4 (IgG_2b, kappa), using cell-based immunization and screening (CBIS) method and investigated hPD-L1 expression in oral cancers. L₁Mab-4 reacted with oral cancer cell lines (Ca9-22, HO-1-u-1, SAS, HSC-2, HSC-3, and HSC-4) in flow cytometry and stained oral cancers in a membrane-staining pattern. L₁Mab-4 stained 106/150 (70.7%) of oral squamous cell carcinomas, indicating the very high sensitivity of L₁Mab-4. These results indicate that L₁Mab-4 could be useful for investigating the function of hPD-L1 in oral cancers.     

N-(4-(6,7-Disubstituted-quinolin-4-yloxy)-3-fluorophenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides: A novel series of dual c-Met/VEGFR2 receptor tyrosine kinase inhibitors

A series of N-(4-(6,7-disubstituted-quinolin-4-yloxy)-3-fluorophenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides targeting c-Met and VEGFR2 tyrosine kinases was designed and synthesized. The compounds were potent against these two enzymes with IC₅₀ values in the low nanomolar range in vitro, possessed favorable pharmacokinetic profiles and showed high efficacy in vivo in several human tumor xenograft models in mice.     

Syntheses of 1-[(2-Hydroxyethoxy)methyl]- and 1-[(1,3-Dihydroxy-2-Propoxy)methyl]- Derivatives of 5-Substituted-2,4-difluorobenzene: Unnatural Acyclo Thymidine Mimics for Evaluation as Anticancer and Antiviral Agents

Abstract

A group of 1-[(2-hydroxyethoxy)methyl]- (12) and 1-[(1,3-dihydroxy-2-propoxy)methyl]- (13) derivatives of 2,4-difluorobenzene possessing a variety of C-5 substituents (R = Me, H, I, NO₂) were designed with the expectation that they may serve as acyclic 5-substituted-2′-deoxyuridine (thymidine) mimics. Compounds 12 and 13 (R = Me, H, I) were inactive as anticancer agents (C₅₀ = 10^?3 to 10^?4 M range), whereas the 5-nitro compounds (12d, 13d) exhibited weak-to-moderate cytotoxicity (CC₅₀ = 10^?5 to 10^?6 M range) against a variety of cancer cell lines. All compounds prepared (12a-d, 13a-d) were inactive as antiviral agents in a broad-spectrum antiviral screen that also included the human immunodeficiency virus (HIV-1 and HIV-2) and herpes simplex virus (HSV-1 and HSV-2).     

Novel 1-(2-aminopyrazin-3-yl)methyl-2-thioureas as potent inhibitors of mitogen-activated protein kinase-activated protein kinase 2 (MK-2)

Novel 1-(2-aminopyrazin-3-yl)methyl-2-thioureas are described as inhibitors of mitogen-activated protein kinase-activated protein kinase 2 (MK-2). These compounds demonstrate potent in vitro activity against the enzyme with IC₅₀ values as low as 15 nM, and suppress expression of TNFα in THP-1 cells and in vivo in an acute inflammation model in mice. The synthesis, structure–activity relationship (SAR), and biological evaluation of these compounds are discussed.     

Synthesis and evaluation of 3-(benzylthio)-5-(1H-indol-3-yl)-1,2,4-triazol-4-amines as Bcl-2 inhibitory anticancer agents

A series of substituted 3-(benzylthio)-5-(1H-indol-3-yl)-4H-1,2,4-triazol-4-amines has been synthesised and tested in vitro as potential pro-apoptotic Bcl-2-inhibitory anticancer agents. Synthesis of the target compounds was readily accomplished in good yields through a cyclisation reaction between indole-3-carboxylic acid hydrazide and carbon disulfide under basic conditions, followed by S-benzylation. Active compounds, such as the nitrobenzyl analogue 6c, were found to exhibit sub-micromolar IC₅₀ values in Bcl-2 expressing human cancer cell lines. Molecular modelling and ELISA studies further implicated anti-apoptotic Bcl-2 as a candidate molecular target underpinning anticancer activity.     

New AZT Analogues Having 5′-Alkylsulfonyl Groups: Synthesis and Anti-HIV Activity

New derivatives of azidothymidine (AZT) substituted by alkyl and alkylsulphonyl groups at N-3 and C-5′, respectively, have been synthesized. The new synthesized derivatives showed remarkable anti-HIV-1 and HIV-2 activity in MT-4 cells. Compounds 8 and 10 have IC₅₀ values of 0.83 and 0.31 μg/mL against HIV-1 with therapeutic index of 83 and 403, respectively, and IC₅₀ values of 0.93 and 0.29 μg/mL against HIV-2 with therapeutic index of 74 and 431, respectively. This means that compounds 8 and 10 were cytotoxic to MT-4 cells at CC₅₀ of 69.2 μg/mL and 125 μg/mL, respectively.     

5-((1-Aroyl-1H-indol-3-yl)methylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-diones as potential anticancer agents with anti-inflammatory properties

A series of novel 5-((1-aroyl-1H-indol-3-yl)methylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-diones (3a–z) have been evaluated for in vitro cytotoxicity against a panel of 60 human tumor cell lines. Compound 3k exhibited the most potent growth inhibition against melanoma MDA-MB-435 cells (GI₅₀ = 850 nM), against leukemia SR cancer cells (GI₅₀ = 1.45 μM), and OVCAR-3 (GI₅₀ = 1.26 μM) ovarian cancer cell lines. The structurally related compound 3s had a GI₅₀ value of 1.77 μM against MDA-MB-435 cells. The N-naphthoyl analogue 3t had GI₅₀ values of 1.30 and 1.91 μM against HOP-92 non-small cell lung cancer and MDA-MB-435 melanoma cell lines, respectively. The related analogue 3w had GI₅₀ values of 1.09 μM against HOP-92 non-small cell lung cancer cell lines. Interestingly, docking of the two active molecules 3k and 3w into the active site of COX-2 indicates that these compounds are COX-2 ligands with strong hydrophobic and hydrogen bonding interactions. Thus, compounds 3k, 3t, 3s, and 3w constitute a new class of anticancer/anti-inflammatory agents that may have unique potential for cancer therapy.     

N-(3-fluoro-4-(2-arylthieno[3,2-b]pyridin-7-yloxy)phenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides: A novel series of dual c-Met/VEGFR2 receptor tyrosine kinase inhibitors

A series of N-(3-fluoro-4-(2-arylthieno[3,2-b]pyridin-7-yloxy)phenyl)-2-oxo-3-phenylimidazolidine-1-carboxamides targeting c-Met and VEGFR2 tyrosine kinases was designed and synthesized. The compounds were potent against these two enzymes with IC₅₀ values in the low nanomolar range in vitro, possessed favorable pharmacokinetic profiles and showed high efficacy in vivo in several human tumor xenograft models in mice.     

Ligand design,synthesis and biological anti-HCV evaluations for genotypes 1b and 4a of certain 4-(3- & 4-[3-(3,5-dibromo-4-hydroxyphenyl)-propylamino]phenyl) butyric acids and 3-(3,5-dibromo-4-hydroxyphenyl)-propylamino-acetamidobenzoic acid esters

4-(4-[N-1-carboxy-3-(3,5-dibromo-4-hydroxyphenyl)-3-oxo-propylamino]phenyl)-4-oxo-butyric acid (V), 4-(3- & 4-[N-1-carboxy-3-(3,5-dibromo-4-hydroxyphenyl)-3-oxo-propylaminophenyl]-2-aryl-4-oxo-butyric acids (Xa–e) and 4-(2-alkyl-2-[N-3-(3,5-dibromo-4-hydroxyphenyl)-1-carboxy-3-oxo-propylamino]acetamido) benzoate esters (XVa–e) were designed, synthesized and biologically evaluated as anti-HCV for genotypes 1b and 4a. The design was based on their docking scores with HCV NS3/4A protease-binding site of the genotype 1b (1W3C), which is conserved in the genotype 4a structure. The docking scores predicted that most of these molecules have higher affinity to the HCV NS3/4A enzyme more than Indoline lead. These compounds were synthesized and evaluated for their cytopathic inhibitory activity against RAW HCV cell cultures of genotype 4a and also examined against Huh 5–2 HCV cell culture of genotype 1b, utilizing Luciferase and MTS assays. Compounds Xa and Xb have 95 and 80% of the activity of Ribavirin against genotype 4a and compounds XVa, XVb and XVd exerted high percentage inhibitory activity against genotype 1b equal 87.7, 84.3 and 82.8%, respectively, with low EC₅₀ doses.     

Synthesis of novel 5-(3-alkylquinolin-2-yl)-3-aryl isoxazole derivatives and their cytotoxic activity

The propargyl alcohol on reaction with aldoxime and NaOCl in DCM gave exclusively (3-arylisoxazol-5-yl) methanol 1. The compound 1 was oxidized to an aldehyde 2 followed by reaction with aniline resulted in Schiff’s base 3. The compounds 3 were further reacted with various aldehydes having α-hydrogen using molecular iodine as catalyst and which yielded 5-(3-alkylquinolin-2-yl)-3-aryl isoxazole derivatives 4. All the final compounds 4 were screened against four human cancer cell lines (A549, COLO 205, MDA-MB 231 and PC-3) and among these compounds 4n showed potent cytotoxicity against all the cell lines at IC₅₀ values of <12 μM.     

1-(3-Aryloxyaryl)benzimidazole sulfones are liver X receptor agonists

A series of 1-(3-aryloxyaryl)benzimidazoles incorporating a sulfone substituent (6) was prepared. High affinity LXR ligands were identified (LXRβ binding IC₅₀ values <10 nM), some with excellent agonist potency and efficacy in a functional assay of LXR activity measuring ABCA1 mRNA increases in human macrophage THP1 cells. The compounds were typically stable in liver microsome preparations and had good oral exposure in mice.