Synthesis and antiproliferative activity of monocationic arylthiophene derivatives

New bithiophene derivative attenuated Alzheimer's disease induced by aluminum in a rat model via antioxidant activity and restoration of neuronal and synaptic transmission

BACKGROUND

One of the hypotheses that leads to an increased incidence of Alzheimer's disease (AD) is the accumulation of aluminum in the brain's frontal cortex. The present study aimed to evaluate the therapeutic role of a novel bithiophene derivative at two doses against AlCl3-induced AD in a rat model.

METHODOLOGY

Adult male rats were divided into six groups, 18 rats each. Group 1: naïve animals, group 2: animals received a daily oral administration of bithiophene dissolved in DMSO (1 mg/kg) for 30 days every other day, groups 3-6: animals received a daily oral administration of AlCl3 (100 mg/kg/day) for 45 consecutive days. Groups 4 and 5 received an oral administration of low or high dose of the bithiophene (0.5 or 1 mg/kg, respectively). Group 6; Animals were treated with a daily oral dose of memantine (20 mg/kg) for 30 consecutive days.

MAIN FINDINGS

Al disturbed the antioxidant milieu, elevated the lipid peroxidation, and depleted the antioxidants. It also disturbed the synaptic neurotransmission by elevating the activities of acetylcholine esterase and monoamine oxidase resulting in the depletion of dopamine and serotonin and accumulation of glutamate and norepinephrine. Al also deteriorated the expression of genes involved in apoptosis and the production of amyloid-β plaques as well as phosphorylation of tau. The new bithiophene at the low dose reversed most of the previous deleterious effects of aluminum in the cerebral cortex and was in many instances superior to the reference drug; memantine.

CONCLUSION

Taking together, the bithiophene modulated the AD etiology through antioxidant activity, prevention of neuronal and synaptic loss, and probably mitigating the formation of amyloid-β plaques and phosphorylation of tau.

Photophysical properties of push-pull monocationic D-π-A+ thiophene based derivatives: Fluorosolvatochromism and pH studies

Photophysical properties of two thiophene salts of the form D-π-A⁺ are studied in several solvents and at various pH values of the aqueous solution. The studied compounds embrace methoxy group as electron donating moiety at one end and cationic amidine group with and without fluorine atom at the ortho position of the amidine group as the electron withdrawing group at the other end of the molecules and separated by thiophene ring. The two thiophene derivatives are 4-(5-(4-methoxyphenyl)thiophen-2-yl)benzamidine hydrochloride salt (MOTB) and 2-fluoro-4-(5-(4-methoxyphenyl) thiophen-2-yl)benzamidine hydrochloride salt (FMOTB). The observed changes in the fluorescence emission spectra with the nature of the solvent were found to be much more pronounced than the corresponding absorption spectra which signify an emission from the intramolecular charge transfer state. The higher bathochromic shift in the fluorescence emission spectra than the absorption spectra indicates that the excited state dipole moment is larger than that of the ground state. It has also been observed that the presence of the fluorine atom in the electron withdrawing part does not show any changes in the absorption spectra while a clear bathochromic shift is observed in the fluorescence emission spectra indicating an enhanced strength of the electron withdrawing ability in case of FMOTB. Effect of pH was also studied and pK_a values were evaluated. The observed photophysical properties were correlated to the normalized solvent polarity parameter (E_T^N) when solvents are classified to protic and aprotic solvents. This designates the importance of hydrogen bonding interactions. We have also applied a couple of linear solvation energy relationships for better understanding of the exact contribution of each solvent parameter on each photophysical property. We have found that both Catalán's and Laurence's treatments show that the photophysical properties are mainly controlled by the solvent's non-specific interactions. However, these models were not sufficient to interpret the observed data without the inclusion of the participation of the specific interactions.

New thiophene derivative augments the antitumor activity of γ-irradiation against colorectal cancer in mice via anti-inflammatory and pro-apoptotic pathways

BACKGROUND

Colorectal cancer (CRC) is one of the most common types of cancer worldwide and the second cause of cancer-related deaths. It usually starts as an inflammation that progresses to adenocarcinoma. The goal of the present study was to investigate the antitumor efficacy of a new thiophene derivative against CRC in mice and explore the possible associated molecular pathways. The potential of this thiophene derivative to sensitize the CRC tumor tissue to a low dose of gamma irradiation was also investigated.

METHODS

Adult male mice were divided into seven groups; control, group treated with dimethylhydrazine (DMH) for the induction of CRC. The DMH-group was further divided into six groups and treated with either cisplatin, thiophene derivative, γ-irradiation, cisplatin + γ-irradiation, thiophene derivative + γ-irradiation, or left untreated.

RESULTS

DMH induced CRC as evidenced by the macroscopic examination of colon tissues and histopathology, and elevated the activities of cyclooxygenase2 (COX2) and nitric oxide synthase (iNOS). DMH also elevated kirsten rat sarcoma (KRAS) and downregulated the peroxisome proliferator activated receptor (PPARγ) as shown by RT-PCR and Western blotting. DMH exerted anti-apoptotic activity by reducing the expression of phosphorylated p53 and cleaved caspase3 at the gene and protein levels. The flow cytometry analysis showed that DMH elevated the necrosis and reduced the apoptosis compared to the other groups. The colon tissue from DMH-treated mice showed hyperplasia, aberrant crypt foci, loss of cell polarity, typical CRC of grade 4 with lymphocytes and macrophages infiltrating mucosa, muscularis mucosa, and submucosa score 3. Treatment with thiophene derivative or γ-irradiation ameliorated most of these deleterious effects of DMH. The concomitant action of thiophene derivative + γ-irradiation was typified by the better amelioration of tumor incidence and multiplicity, iNOS, PPARγ, p53, caspase 3, and histopathology of colon.

CONCLUSION

Taken together, the new thiophene derivative is a promising therapeutic candidate for treatment of colorectal cancer in mice. It also sensitizes the CRC tumor to the ionizing radiation through anti-inflammatory and pro-apoptotic pathways.

New fluorobenzamidine exerts antitumor activity against breast cancer in mice via pro-apoptotic activity

BACKGROUND

Breast cancer is one of the leading causes of cancer-related morbidities. The present study aimed to evaluate the efficacy of bithiophene-fluorobenzamidine (BFB) against breast cancer induced by 7,12-dimethylbenz(a)anthracene (DMBA) in female Swiss mice and reveal the underlining mechanisms.

METHODS

The mice were randomly divided into five groups; control, BFB-treated group, DMBA-treated group, and the last two groups received DMBA then tamoxifen or BFB.

RESULTS

BFB reduced the tumor incidence by ~ 88% versus 30% after TAM. DMBA significantly increased the expression of CDK1 and HER2 and reduced the expression of p53, p21 (CDKN1A), ESR-α, and CAS3. BFB caused significant down-regulation of CDK1 and HER2 and upregulation of p53, p21, ESR-α, and CAS3. In the DMBA-treated mice, cancerous cells metastasized to several organs. This was prevented by the administration of BFB. The antimetastatic and proapoptotic activities were confirmed in MCF7 cells in vitro by the wound healing and annexin V assays, respectively. Kaplan-Meier analysis showed that the BFB increased survival. In the DMBA group, tumors showed invasive carcinoma of grade III with central necrosis, polymorphism, mitotic activity, and numerous newly formed ductules, and colloidal mucinous secretions within adenoid cysts. BFB administration restored the normal structure of the mammary glands.

CONCLUSION

Taken together, BFB has antitumor, pro-apoptotic, and anti-metastatic activities against breast cancer in mice and therefore, it merits further investigations.

Synthesis of new thienylnicotinamidines: Proapoptotic profile and cell cycle arrest of HepG2 cells

Fourteen new thienylnicotinamidines and their analogs 5a-5k, 12, 13a, and 13b were prepared and their antiproliferative potential was evaluated against the growth of 60 cancer cell lines. The tested compounds had a strong antiproliferative efficacy against almost all cancer cell lines, with the average GI₅₀ at ~2.20 µM. The effect of the thienylnicotinamidines on the growth of normal lung fibroblast cells (WI-38) indicated that these derivatives are safe to the normal cells. The selectivity index (SI) ranges from 5.5- to 42.0-fold. The conceivable mechanisms of action of the effective compounds 5d, 5f, 5g, 5i, 5j, and 5k with high SI were investigated. Although the thienylnicotinamidines are similar in structure, they could be divided into three groups as per their effects on gene expression: The first group (5d and 5f) elevated p53 and caspase 3 expression, the second group (5g and 5i) elevated p53 expression, and the last group (5j and 5k) elevated p53 and reduced topoII expression. Many thienylnicotinamides inhibited the vascular endothelial growth factor receptor-2 (VEGFR-2) in cell lysates at concentrations comparable to or better than pazopanib. The data of caspase 3 expression were confirmed by measuring the protein level by Western blot and the activity of the cleaved active enzyme. The ability to arrest the cell cycle and induce apoptosis was confirmed by flow cytometry. Taken together, two derivatives, 5d and 5f, with a distinctive VEGFR-2 inhibitory activity and a proapoptotic and cell cycle arrest profile merit further investigations.

Anticancer Activity of Extremely Effective Recombinant L-Asparaginase from Burkholderia pseudomallei

L-asparaginase (E.C. 3.5.1.1) purified from bacterial cells is widely used in the food industry, as well as in the treatment of childhood acute lymphoblastic leukemia. In the present study, the Burkholderia pseudomallei L-asparaginase gene was cloned into the pGEX-2T DNA plasmid, expressed in E. coli BL21 (DE3) pLysS, and purified to homogeneity using Glutathione Sepharose chromatography with 7.26 purification fold and 16.01% recovery. The purified enzyme exhibited a molecular weight of ~33.6 kDa with SDS-PAGE and showed maximal activity at 50°C and pH 8.0. It retained 95.1, 89.6%, and 70.2% initial activity after 60 min at 30°C, 40°C, and 50°C, respectively. The enzyme reserved its activity at 30°C and 37°C up to 24 h. The enzyme had optimum pH of 8 and reserved 50% activity up to 24 h. The recombinant enzyme showed the highest substrate specificity towards L-asparaginase substrate, while no detectable specificity was observed for L-glutamine, urea, and acrylamide at 10 mM concentration. THP-1, a human leukemia cell line, displayed significant morphological alterations after being treated with recombinant L-asparaginase and the IC₅₀ of the purified enzyme was recorded as 0.8 IU. Furthermore, the purified recombinant L-asparaginase improved cytotoxicity in liver cancer HepG2 and breast cancer MCF-7 cell lines, with IC₅₀ values of 1.53 and 18 IU, respectively.

Bithiophene derivative induced apoptosis and suppression of Akt pathway in mouse leukemic model

BACKGROUND: Bithiophene derivatives show a promising anti-cancer potential. We previously showed that Bithienyl Fluorobenzamidine (BFB) has an anti-proliferative effect against several leukemia cell lines. Acute myeloid leukemia (AML) accounts for 18% of the total leukemia cases worldwide with heavier burden during the past 30 years. Therefore, the main aim remains the discovery of safe and effective medications. OBJECTIVE: The current research aims to investigate the anti-cancer efficacy of BFB and its effect on the apoptosis in the 7,12-Dimethylbenz[a]anthracene (DMBA) induced AML in mice. METHODS: AML was induced in mice by DMBA and then treated by 2 different doses of BFB. After BFB treatment, the hematological and histological pattern changes was examined. Furthermore, the molecular effect of BFB on apoptosis, cell cycle markers and Protein kinase B (Akt) pathway was examined using qPCR, Western blotting and ELISA. RESULTS: BFB treatment ameliorates leukemia histological and hematological markers significantly, despite non-significant changes in normal mice. This improvement exhibits cell cycle arrest and apoptosis induction, represented by elevation of tp53/p53, p21/p21, Caspase3 and downregulation of ckk1/Cdk1 in the bone marrow, as well as Akt pathway suppression. CONCLUSIONS: Our results establishes BFB as a promising therapeutic candidate against AML through cell cycle arrest, apoptosis induction and Akt pathway modulation.

Novel cationic aryl bithiophene/terthiophene derivatives as corrosion inhibitors by chemical, electrochemical and surface investigations

Two novel bithienyl fluorobenzamidine derivatives namely, 4-([2,2′:5′,2′′-terthiophen]-5-yl)-2-fluorobenzamidine hydrochloride salt (MA-1615), 5′-(4-amidino-3-fluorophenyl)-[2,2′-bithiophene]-5-carboxamidine dihydrochloride salt (MA-1740) were synthesized, characterized and their corrosion inhibition properties were evaluated by electrochemical methods for carbon steel (C-steel) in 1 M HCl. Experimental investigations revealed that the inhibition effectiveness of the investigated inhibitors (INHs) by the Tafel polarization method followed the order: MA-1740 (96.9%) > MA-1615 (95.6%), demonstrating higher efficiency than inhibitors of similar structure reported in the literature. The investigated bithiophene derivatives exhibit mixed-type corrosion inhibition characteristics by blocking the active sites on the surface of C-steel. EIS study revealed that the INHs behave as interface-type corrosion inhibitors. UV–Visible spectrometric measurements confirmed a complex formation between the Fe²⁺ cation released during the corrosion reactions and inhibitor molecules.

New N-(1,3,4-thiadiazol-2-yl)furan-2-carboxamide derivatives as potential inhibitors of the VEGFR-2

The present study reports the synthesis and biological evaluation of a new series of novel N-(1,3,4-thiadiazol-2-yl)furan-2-carboxamide derivatives. The reactions were executed under both conventional and microwave irradiation conditions. An enhancement in the synthetic yields and rates was observed when the reactions were carried out under the microwave compared with the classical conditions. The structures of the products were ascertained by different analytical and spectral analyses. The antiproliferative activities were evaluated against three human epithelial cell lines; breast (MCF-7), colon (HCT-116), and prostate (PC-3) using MTT assay technique and doxorubicin was utilized as a reference drug. Besides, molecular docking studies were also performed and the vascular endothelial growth factor recptor-2 (VEGFR-2) was identified as a potential molecular target. Compounds 6, 7, 11a, 11b, 12, 14, and 16 showed promising antiproliferative activity against the three cancer cell lines investigated. Compounds 2 and 15b had significant antiproliferative activities against only colon and breast cells but not against the prostate cells. All the active antiproliferative compounds were highly selective. All the active antiproliferative compounds were good inhibitors of the VEGFR-2 at 7.4-11.5 nM compared with Pazopanib. Compound 7 with the most favorable orientation to the VEGFR-2 from the docking studies, was also the best inhibitor of the receptor. The antiproliferative activity of these compounds is in partial caused by their ability to inhibit the VEGFR-2 and since other molecular targets were not examined, other possibilities cannot be ruled out.

Synthesis, Antiproliferative activity, and apoptotic profile of New Derivatives from the Meta Stable Benzoxazinone Scaffold

BACKGROUND

Cancer exerts a huge strain on the health system. The emerging resistance to the current chemotherapies demands the continuous development of new anticancer agents with lower cost, higher efficacy, and greater specificity.

OBJECTIVE

Development of selective small molecules targeted anticancer agents.

METHODS

The behavior of benzoxazinone 2 towards nitrogen nucleophiles such as hydrazine hydrate, formamide, ethanolamine, aromatic amines, and thiosemcarbazide was described. The behavior of the amino quinazolinone 3 towards carbon electrophiles and P2S5 was also investigated. The antiproliferative activity of 17 new benzoxazinone derivatives was examined against the growth of three human cancer cell lines; liver HepG2, breast MCF-7, and colon HCT-29, in addition to the normal human fibroblasts WI-38 and the selectivity index was calculated. The possible molecular pathways such as the cell cycle and apoptosis were investigated.

RESULTS

Derivatives 3, 7, 8, 10, 13, and 15 had a significant (less than 10 µM) antiproliferative activity against the three cancer cell lines investigated. Derivative 7 showed the best antiproliferative profile comparable to that of doxorubicin. The selectivity index for all the effective derivatives ranged from ~5-12 folds indicating high selectivity against the cancer cells. Derivative 15 caused ~ 7-fold and 8-fold inductions in the expression of p53 and caspase3, respectively. It also caused a ~ 60% reduction in the expression of both topoisomerase II (topoII) and cyclin-dependent kinase 1 (cdk1). Derivatives 3, 7, and 8 had a similar profile; ~ 6-8-fold increases in the expression of p53 and caspase3 but these compounds were devoid of any significant effect on the expression of topoII and cdk1. Derivatives 10 and 13 were also similar and resulted in a ~6-fold elevation in the expression of caspase3, and more than 60% downregulation in the expression of topoII. The results of the gene expression of topoII and caspase 3 were confirmed by the measurement of the topoII concentration and caspase3 activity in the HepG2 cells.

CONCLUSION

Six derivatives exerted their antiproliferative activity by arresting the cell cycle (decreasing cdk1), preventing the DNA duplication (downregulating topo II), and by inducing apoptosis (inducing p53 and caspase3). One common feature in all the six active derivatives is the presence of free amino group. These compounds have merit for further investigations.

New antiparasitic flexible triaryl diamidines, their prodrugs and aza analogues: Synthesis, in vitro and in vivo biological evaluation, and molecular modelling studies

Dicationic diamidines have been well established as potent antiparasitic agents with proven activity against tropical diseases like trypanosomiasis and malaria. This work presents the synthesis of new mono and diflexible triaryl amidines (6a-c, 13a,b and 17), their aza analogues (23 and 27) and respective methoxyamidine prodrugs (5, 7, 12a,b, 22 and 26). All diamidines were assessed in vitro against Trypanosoma brucei rhodesiense (T. b. r.) and Plasmodium falciparum (P. f.) where they displayed potent to moderate activities at the nanomolar level with IC₅₀s = 11-378 nM for T. b. r. and 4-323 nM against P. f.. In vivo efficacy testing against T. b. r. STIB900 has shown the monoflexible diamidine 6c as the most potent derivative in this study eliciting 4/4 cures of infected mice for a treatment period of >60 days upon a 4 × 5 mg/kg dose i. p. treatment. Moreover, thermal melting analysis measurement ΔT_m for this series of diamidines/poly (dA-dT) complexes fell between 0.5 and 19 °C with 6c showing the highest binding to the DNA minor groove. Finally, a 50 ns molecular dynamics study of an AT-rich DNA dodecamer with compound 6c revealed a strong binding complex supported by vdW and electrostatic interactions.

Design, synthesis and evaluation of new quinazolin-4-one derivatives as apoptotic enhancers and autophagy inhibitors with potent antitumor activity

This work presents the design and synthesis of a series of new quinazolin-4-one derivatives, based on the established effectiveness of quinazoline-based small molecules as anticancer agents. Synthesized compounds were more potent against MCF-7 than A-549 with low to submicromolar IC₅₀s. Compound 17 exhibited the best IC₅₀ being equipotent with the positive control doxorubicin (IC_50 = 0.06 μM) and better than 5-fluorouracil (IC_50 = 2.13 μM). Compound 17 was further tested against MDA-MB-231 and MCF-10A and was found to be > 2 folds more cytotoxic on MCF-7. Significant apoptotic activity was elicited by 17 on MCF-7 where it increased apoptotic cell death along with induction of pre-G1 and G1-phase cell cycle arrest. Similarly, 17 was able to induce apoptosis in MD-MB-231 treated cells associated with a disruption of the cell cycle causing arrest at the pre-G1 and S phases. Investigation of gene expression in MCF-7 demonstrated an increased expression of the proapoptotic genes P53, PUMA, Bax, caspases 3, 8 and 9 and a decrease of the anti-apoptotic gene Bcl2. Also, 17 reduced autophagy giving way for apoptosis to induce cancer cells death. This latter observation was associated with downregulation of EGFR and its downstream effectors PI3K, AKT and mTor. As its biomolecular target, 17 also inhibited EGFR similar to erlotinib (IC₅₀ = 0.072 and 0.087 μM, respectively). Additionally, in vivo testing in a mouse model of breast cancer affirmed the anti-tumor efficacy of 17. Finally, docking of 17 against EGFR ATP binding site demonstrated its ability to bind with EGFR resembling erlotinib.

The Antitumor Activity of a Novel Fluorobenzamidine against Dimethylhydrazine- Induced Colorectal Cancer in Rats

BACKGROUND

Colorectal cancer is among the leading causes of death worldwide. The incidence of deaths is expected to be 11.4 million in 2030.

OBJECTIVE

We aimed to evaluate the in vitro and in vivo antioxidant and antitumor activities of a novel Bithiophene- Fluorobenzamidine (BFB) against DMH-induced colorectal cancer in rats.

METHODS

The antiproliferative activity of BFB against HCT-116 colon cancer cells and apoptotic genes was assessed. In vivo study was also conducted in which 80 adult male rats were divided into 5 groups; control, BFB, and the other 3 groups were injected with DMH (20mg/kg, s.c., for 9 weeks). Group 4 was injected with 5 doses of cisplatin (2.5mg/kg, i.p over 21 weeks) and group 5 was injected with 3 doses/week of BFB (2.5mg/kg, i.p, for 21 weeks).

RESULTS

BFB exhibited weak to moderate in vitro antioxidant activity. It had a strong antiproliferative activity with IC50 ~0.3µg/ml. BFB induced extrinsic apoptosis through the upregulation of FasL, TRAL, p53 and caspase-8, and intrinsic apoptosis through the downregulation of Bcl-2 and survivin. BFB decreased the tumor incidence, multiplicity and size and improved the decreased body weight. BFB also ameliorated the functions of kidney and liver and antioxidants deteriorated by DMH. BFB significantly improved the pathological changes caused by DMH in colon tissues.

CONCLUSION

BFB showed a very promising antitumor activity against colorectal cancer induced by DMH in rats without causing hepato- or nephrotoxicity.

Anticancer activity of new cationic arylthiophenes against hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the second most common cancer-related death in the world. No effective curative option exists for the treatment of HCC. The available drugs exhibit severe toxic effects and low therapeutic index.

AIM

This work aimed to examine different monocationic arylthiophene derivatives for possible use as chemotherapeutic agents against HCC.

METHODS

The IC₅₀ values for the compounds were determined. The mechanism of cytotoxicity was further investigated using different methods.

RESULTS

Compound 2j proved to retain the highest cytotoxicity in comparison to as a positive control. The selectivity index of compound 2j revealed the safety to normal cells. Moreover, compound 2j was able to inhibit HepG2 cells´ migration and division. The anticancer effect of compound 2j was found to be partially via cell cycle arrest, activation of the tumour suppressor p53 protein, and induction of apoptosis via both intrinsic and extrinsic pathways. Compound 2j has a potential sensitization activity and significantly reduced the IC₅₀ values for the anticancer drugs doxorubicin, cisplatin, and taxol.

CONCLUSION

The tested arylthiophenes showed a potent cytotoxicity against HepG2 cells and were safe to normal cells. The most active compound 2j was found to be able to inhibit cell division and migration and also to induce apoptosis. Compound 2j also proved to have a sensitization effect on standard anticancer drugs.

Synthesis of new thienylpicolinamidine derivatives and possible mechanisms of antiproliferative activity

Three thienylpicolinamidine derivatives 4a-c were prepared from their corresponding picolinonitriles 3a-c on treatment with lithium trimethylsilylamide, LiN(TMS)2, followed by a de-protection step using ethanol/HCl (gas). DFT calculations were used to optimize the geometric structure of the newly synthesized picolinamidines. The comparison of DFT calculated spectral data with the experimental data (1H-NMR and 13C-NMR) showed a good agreement. The in vitro antiproliferative activity of the cationic compounds 4a-c was determined against 60 cancer cell lines representing nine types of cancer. The tested picolinamidines were highly active with compounds 4a and 4b eliciting mainly cytotoxic activity with GI values ranging from -7.17 to -86.03. Leukemia (SR and K-562), colon (SW-620 and HT29), and non-small cell lung cancer (NCI-H460) cell lines were the most responsive to the investigated picolinamidines. In particular, 4-methoxyphenyl derivative 4a showed a profound growth deterring power with GI50 of 0.34 μM against SR, 0.43 μM against SW-620, and 0.52 μM against NCI-H460. The three tested picolinamidines elicited potent GI50 values against all tested cell lines at low micromolar to sub-micromolar level. The new picolinamidines were selective and did not affect normal human fibroblasts. The selectivity index ranged from 13-21 μM. The novel picolinamidines downregulated the expression of key genes in the cell cycle, cdk1 and topoII, but did not affect p53 or txnrd1. Compounds 4b and 4c caused a significant reduction in the concentrations of TopoII and MAPK proteins but were devoid of any effect on the activity of caspase 3. Taken together, these promising anticancer candidates are effective at very low concentrations and safe to normal cells, and most probably work through arresting the cell cycle, and therefore, they deserve further investigations.

Thiophene-based derivatives as anticancer agents: An overview on decade's work

Heterocyclic compounds hold a pivotal place in medicinal chemistry due to their wide range of biological activities and thus, are exhaustively explored in the field of drug design and development. Continuous efforts are being carried out for the development of medicinal agents especially, for dreadful diseases like cancer. Thiophene, a sulfur containing heterocyclic scaffold, has emerged as one of the relatively well-explored scaffold for the development of library of molecules having potential anticancer profile. Thiophene analogs have been reported to bind with a wide range of cancer-specific protein targets, depending on the nature and position of substitutions. Accordingly, thiophene analogs have been reported to cause their biological action through inhibition of different signaling pathways involved in cancer. Functionally, different anticancer targets require different structural features, so researchers have tried to synthesize new thiophene derivatives with varied substitutions. In the present review, authors have presented the information available on thiophene-based molecules as anticancer agents with special focus on synthetic methodologies, biological profile and structure activity relationship (SAR) studies. Various patents granted for thiophene containing molecules as anticancer have also been included.

The Anti-Proliferative Activity of Anisosciadone: A New Guaiane Sesquiterpene from Anisosciadium lanatum

BACKGROUND

The increase in cancer rate and the development of resistant tumors require a continuous search for new anticancer agents.

AIMS

This study aimed to analyze and identify the chemical constituents of Anisosciadium lanatum, and to investigate the antiproliferative activity of the identified constituents against various human cell lines (HepG2, MCF7, HT29, A549, and PC3) along with the possible molecular mechanisms involved.

METHODS

The structure of the isolated compounds was determined by spectroscopic techniques including HRFABMS, GC-MS, IR, and 400 MHz 1D and 2D NMR analyses (1H, 13C NMR, DEPT, 1H-1H COSY, HMQC, HMBC and NOESY). The antiproliferative activity and IC50 value of the isolated compounds were measured and compared to doxorubicin.

RESULTS

A new guaiane sesquiterpene containing a rare epoxide structural element, 10β,11β-epoxy-1α,4β,5β,7αΗ- guaiane-9-one, anisosciadone (1), and stigmasterol (2) have been isolated from the plant. Anisosciadone (1) showed a significant antiproliferative activity against liver, colon, and lung cells only, while stigmasterol (2) had a significant activity against liver, colon, and breast cells. Both 1 and 2 caused no cytotoxicity to normal fibroblasts. Anisosciadone elevated the expression and activity of Caspase 3 as well as p53 expression without affecting Caspase 9 in HepG2 cells. It also caused ~ 50% downregulation in cdk1 expression.

CONCLUSION

Taken together, anisosciadone was specific in action against cancer cells and induced apoptosis in liver cells. It also has a unique feature by elevating the expression and activity of Caspase 3 without affecting the initiator Caspase 9. Therefore, anisosciadone deserves more investigation as a targeted therapy for cancer.

Substitution at Phenyl Rings of Chalcone and Schiff Base Moieties Accounts for their Antiproliferative Activity

BACKGROUND

In a continuous combat against cancer, which is one of the leading causes of mortality now, chalcone and Schiff bases moieties have been incorporated and their antiproliferative activities and associated mechanisms against liver (HepG2) and breast (MCF-7) cell lines in addition to normal fibroblasts (WI-38) have been examined.

METHODS

Derivatives 4 and 5 of Schiff bases only and chalcone derivatives of Schiff bases 1 and 2 were devoid of any antiproliferative activity. All three compounds (3, 6, and 7) with significant antiproliferative activity were selective and caused no growth inhibition in normal fibroblasts. Derivative 3 was a chalcone only with IC50 of ~20 µM and has a very interesting signature where it enhanced apoptosis in HepG2 by stimulating the expression of downstream execution caspase 3 without affecting neither p53 nor initiator caspase 9. In spite of the structural similarity between compounds 6 and 7, compound 6 discerned itself with a unique IC50 of ~ 10 µM.

RESULTS

The antiproliferative activity of derivative 6 could be attributed to its unique capability of formation of free radicals such as phenoxide radicals which arrested the cell cycle through enhancing the expression of p53 and induced apoptosis by induction of both caspases 9 and 3. It was the only investigated derivative that inhibited the tyrosine kinase activity by 89%.

CONCLUSIONS

The antiproliferative activity of the compounds under investigation considerably depended on the nature of the substituent at position 4 in phenyl rings of both chalcone and Schiff base fragments. Derivative 6 with electron withdrawing chlorine substitution on the phenyl ring of Schiff base fragment and an electron donating methoxy group on the phenyl ring of chalcone fragment was the most active member.

Synthesis and Reactivity of 6,8-Dibromo-2-ethyl-4H-benzo[d][1,3]oxazin-4-one Towards Nucleophiles and Electrophiles and Their Anticancer Activity

BACKGROUND

The genetic heterogeneity of tumor cells and the development of therapy-resistant cancer cells in addition to the high cost necessitate the continuous development of novel targeted therapies.

METHODS

In this regard, 14 novel benzoxazinone derivatives were synthesized and examined for anticancer activity against two human epithelial cancer cell lines; breast MCF-7 and liver HepG2 cells. 6,8-Dibromo-2- ethyl-4H-benzo[d][1,3]oxazin-4-one was subjected to react with nitrogen nucleophiles to afford quinazolinone derivatives and other related moieties (3-12). Benzoxazinone 2 responds to attack with oxygen nucleophile such as ethanol to give ethyl benzoate derivative 13. The reaction of benzoxazinone 2 with carbon electrophile such as benzaldehyde derivatives afforded benzoxazinone derivatives 14a and 14b.The structure of the prepared compounds was confirmed with spectroscopic tools including IR, 1H-NMR, and 13C-NMR.

RESULTS

Derivatives 3, 9, 12, 13, and 14b exhibited high antiproliferative activity and were selective against cancer cells showing no toxicity in normal fibroblasts. Derivative 3 with NH-CO group in quinazolinone ring was effective only against breast cells, while derivative 12 with NH-CO group in imidazole moiety was only effective against liver cells probably through arresting cell cycle and enabling repair mechanisms. The other derivatives (9, 13, and 14b) had broader antiproliferative activity against both cell lines. These derivatives enhance the expression of the p53 and caspases 9 and 3 to varying degrees in both cell lines. Derivative 14b caused the highest induction in the investigated genes and was the only derivative to inhibit the EGFR activity.

CONCLUSIONS

The unique features about derivative 14b could be attributed to its high lipophilicity, high carbon content, or its extended conjugation through planar aromatic system. More investigations are required to identify the lead compound(s) in animal models.

Synthesis of new oxadiazol-phthalazinone derivatives with anti-proliferative activity; molecular docking, pro-apoptotic, and enzyme inhibition profile

Background and aim: The current study reports the synthesis and biological evaluation of two novel series of 4-(5-mercapto-1,3,4-oxadiazol-2-yl)phthalazin-1(2H)-one derivatives. Methods: The synthetic reactions were carried out under both conventional and ultrasonic irradiation conditions. The anti-proliferative activity of the newly synthesized compounds against two human epithelial cell lines; liver (HepG2) and breast (MCF-7) in addition to normal fibroblasts (WI-38) was investigated. In addition to molecular docking studies, the possible mechanism(s) of action were also explored. Results: In general, an improvement in synthetic rates and yields was observed when reactions were carried out under sonication compared with classical conditions. The structures of the products were established based on analytical and spectral data. Derivatives 2e and 7d, in addition to compound 1, had significant and selective anti-proliferative activity against liver and breast cancer cell lines without harming normal fibroblasts. These derivatives arrested the cell cycle progression and/or induced apoptosis. This has been manifested by the elevation in the expression of p53 and caspase 3, down-regulation of cdk1, and a reduction in the concentrations of MAPK and Topo II at submicromolar concentrations. The latter results confirmed the molecular docking study. Conclusions: Compound 1 had the best profile on the gene and protein levels (arresting cell cycle and inducing apoptosis). The ability of compounds 1 and 2e to inhibit both MAPK and Topo II nominates these derivatives as potential candidates for further anticancer and antitumor studies.

Photophysical properties and fluorosolvatochromism of D–π–A thiophene based derivatives

Solvation-dependent photophysical properties of two push–pull thiophene-based compounds with donor–π–acceptor (D–π–A) structures were investigated using absorption, fluorescence emission and time resolved spectroscopy, and supported by different solvation models. Intramolecular charge transfer characteristics of the structurally similar 2-fluoro-4-(5-(4-methoxyphenyl)thiophen-2-yl)benzonitrile (MOT) and 4-(5-(4-(dimethylamino)phenyl)thiophen-2-yl)-2-fluorobenzonitrile (DMAT) were investigated. Significant enhancement of intramolecular charge transfer strength has been observed through molecular structure modification of the electron donating group from a methoxy to dimethylamine group. Ground state absorption spectra show a small red shift of about 10 nm and 18 nm while the fluorescence emission spectra show a large red shift of about 66 nm and 162 nm on changing from the nonpolar cyclohexane to the aprotic polar DMSO for MOT and DMAT, respectively. Dipole moment change from the ground state to the charge transfer excited state is calculated to be 6.6 D in MOT and 9.0 D in DMAT. The fluorescence quantum yield, fluorescence lifetime and the derived radiative and non-radiative rate constants were found to be better correlated to the emission energy rather than any of the solvent properties. Three multi-parametric relationships were used in the interpretation of the specific versus non-specific solute–solvent interactions, namely, Kamlet–Taft, Catalán and Laurence et al. models. The findings of these approaches are used to extract useful information about different aspects of solvent effects on the photophysical properties of the two studied compounds. Kamlet–Taft solvatochromic model indicates that non-specific interactions are dominant in controlling the photophysical properties. Catalán's solvent dipolarity/polarizability parameter is found to play a significant role in solvatochromic behaviour which is also designated by the Laurence model.

Solvation-dependent photophysical properties of two push–pull thiophene-based compounds with donor–π–acceptor (D–π–A) structures were investigated using absorption, fluorescence emission and time resolved spectroscopy, and supported by different solvation models.

Diversity-oriented approach to functional thiophene dyes by Suzuki coupling-lithiation one-pot sequences

Functional thiophenes, e.g. for organic metal-free dye sensitized solar cells (DSSC), are accessible efficiently via a divergent and diversity-oriented synthetic strategy.

Novel Nicotinonitrile Derivatives Bearing Imino Moieties Enhance Apoptosis and Inhibit Tyrosine Kinase

Background:

Fused heterocyclic containing pyrazolopyridine systems have several medicinal activities including cytotoxic and carcinostatic activities.

Objective:

To investigate the antiproliferative activity and associated mechanism(s) of a novel series of nicotinonitrile derivatives.

Method:

The series has been synthesized by the reaction of hydrazonoyl chlorides with each of 4-(4- methoxyphenyl)-3-methyl-6-oxo-6,7-dihydro-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile and 2-amino-4-(4- methoxyphenyl)-6,7-dihydro-5H-cyclopenta[b]pyridine-3-carbonitrile in dioxane in basic medium. The assigned structures for each of the new products were identified via elemental and spectral data. Moreover, the cytotoxic activity for some selected products was screened.

Results:

Derivatives 5g, 7i, 8 and 9 had their IC50 at ~ 1-3 µM and derivatives 7b, 7d, and 7f were similar to 5- fluorouracil and had their IC50 at ~ 5 µM against breast (MCF-7) and colon (HCT-116) cell lines. All derivatives were specific in action and safe to normal fibroblasts (WI38). Only derivative 9 caused some toxicity but at high concentration of 93 µM. These derivatives exerted strong antiproliferative activity through inducing intrinsic apoptosis as indicated from the significant induction of caspases 9 and 3 by 3-6 folds in colon cells and/or inhibiting tyrosine kinase (TK) and hence arresting the cell cycle.

Conclusion:

Compounds 8 and 5g were the most potent anticancer agents inhibiting the TK by 86 and 89% and their IC50 of the enzyme were 311 and 352 nM, respectively. We believe that these derivatives deserve further investigation and these chemical moieties could offer promising anticancer drugs.

Synthesis, antimicrobial, DNA cleavage and antioxidant activities of tricyclic sultams derived from saccharin

Two series of fused tricyclic sultams (carboxylates, 3a, b and 5a, f, g and anilides 5b-e) were synthesized from saccharin and their chemical structures were confirmed by spectroscopic tools. Then, their antibacterial activities and MIC were evaluated against two strains of gram positive and gram-negative bacteria. The MIC values of the tested compounds are in the of range 8-33 μg/ml. In addition, their DNA cleavage ability, binding affinity and their anticancer activities against hepatic cancer cell were tested. And their antioxidant activities were also measured. Four carboxylate derivatives (3a, 5a, 5f and 5g) and one anilide (5d) of the tested compounds proved to be the highest activity all over the study.