Foretinib, a c-MET receptor tyrosine kinase inhibitor, tackles multidrug resistance in cancer cells by inhibiting ABCB1 and ABCG2 transporters

BACKGROUND

ABC transporter-mediated multidrug resistance (MDR) remains a major obstacle for cancer pharmacological treatment. Some tyrosine kinase inhibitors (TKIs) have been shown to reverse MDR. The present study was designed to evaluate for the first time whether foretinib, a multitargeted TKI, can circumvent ABCB1 and ABCG2-mediated MDR in treatment-resistant cancer models.

METHODS

Accumulation of fluorescent substrates of ABCB1 and ABCG2 in ABCB1-overexpressing MES-SA/DX5 and ABCG2-overexpressing MCF-7/MX and their parenteral cells was evaluated by flow cytometry. The growth inhibitory activity of single and combination therapy of foretinib and chemotherapeutic drugs on MDR cells was examined by MTT assay. Analysis of combined interaction effects was performed using CalcuSyn software.

RESULTS

It was firstly proved that foretinib increased the intracellular accumulation of rhodamine 123 and mitoxantrone in MES-SA/DX5 and MCF-7/MX cancer cells, with accumulation ratios of 12 and 2.2 at 25 μM concentration, respectively. However, it did not affect the accumulation of fluorescent substrates in the parental cells. Moreover, foretinib synergistically improved the cytotoxic effects of doxorubicin and mitoxantrone. The means of combination index (CI) values at fraction affected (Fa) values of 0.5, 0.75, and 0.9 were 0.64 ± 0.08 and 0.47 ± 0.09, in MES-SA/DX5 and MCF-7/MX cancer cells, respectively. In silico analysis also suggested that the drug-binding domain of ABCB1 and ABCG2 transporters could be considered as potential target for foretinib.

CONCLUSION

Overall, our results suggest that foretinib can target MDR-linked ABCB1 and ABCG2 transporters in clinical cancer therapy.

Synthesis and cytotoxic activity evaluation of novel imidazopyridine carbohydrazide derivatives

Two series of novel imidazo[1,2-a]pyridine-2-carbohydrazide derivatives have been designed, synthesized, and evaluated for cytotoxic activity. Target compounds were designed in two series: aryl hydrazone derivatives that were devoid of triazole moiety (7a-e) and aryl triazole bearing group (11a-e). In vitro cytotoxicity screening was carried out using MTT assay against three human cancer cells including breast cancer (MCF-7), colon cancer (HT-29), and leukemia (K562) cell lines as well as a non-cancer cell line (Vero). Compound 7d bearing 4-bromophenyl pendant from aryl hydrazone series exhibited the highest cytotoxic potential with IC50 values of 22.6 µM and 13.4 µM against MCF-7 and HT-29 cells, respectively, while it was not toxic towards non-cancer cells up to the concentration of 100 µM. Cell cycle analysis revealed that 7d increased the number of MCF-7 cells in the G0/G1 phase and also induced apoptosis in these cells as revealed by Hoechst 33,258 staining. The molecular mechanism contributing to the anti-proliferative effect of the most potent compound was investigated in silico using Super Pred software and introduced PDGFRA as a plausible target for 7d. Molecular docking and molecular dynamic studies demonstrated Lys627 and Asp836 as key residues interacting with the active compound. Overall, 7d could serve as a suitable candidate for further modifications as a lead anticancer structure.

Cytidine deaminase enzyme activity is a predictive biomarker in gemcitabine-treated cancer patients

BACKGROUND

Gemcitabine is a chemotherapeutic agent, widely used for the treatment of many types of cancer. Cytidine deaminase (CDA) enzyme plays an important role in the metabolism of gemcitabine. This study aimed to assess the power of serum CDA residual activity in predicting drug efficacy and toxicity in gemcitabine-treated cancer patients.

METHODS

This prospective observational study enrolled 63 patients with different types of malignancies who received gemcitabine chemotherapy between May 2019 and January 2022. Blood samples were obtained before the initiation of chemotherapy and serum CDA residual activity was determined using a modification of the Berthelot assay. The patients were followed up for at least 12 months up to 41 months. Overall survival was recorded and treatment-related toxicities were documented according to National Cancer Institute Common Terminology Criteria.

RESULTS

Kaplan-Meier analysis showed that patients with a lower than median CDA value (≤ 8.06 U/mg protein) had a significantly longer survival compared to patients with higher CDA values (> 8.06 U/mg, P ˂ 0.005). Among several potentially involved factors, a significant association between CDA activity and overall survival was observed in univariate analysis (HR = 4.219, 95% CI 1.40-12.74, P = 0.011). On the other hand, the rate of anemia was significantly higher in low-CDA patients compared to high-CDA individuals (P < 0.05).

CONCLUSION

These findings suggest that CDA activity could be a promising biomarker to predict survival and the occurrence of anemia in cancer patients treated with gemcitabine.

Novel quinazoline-1,2,3-triazole hybrids with anticancer and MET kinase targeting properties

Oncogenic activation of receptor tyrosine kinases (RTKs) such as MET is associated with cancer initiation and progression. We designed and synthesized a new series of quinazoline derivatives bearing 1,2,3-triazole moiety as targeted anticancer agents. The MET inhibitory effect of synthesized compounds was assessed by homogeneous time-resolved fluorescence (HTRF) assay and western blot analysis. Sulforhodamine B assay was conducted to examine the antiproliferative effects of synthetic compounds against 6 cancer cell lines from different origins including MET-dependent AsPC-1, EBC-1 and MKN-45 cells and also Mia-Paca-2, HT-29 and K562 cells. The growth inhibitory effect of compounds in a three-dimensional spheroid culture was examined by acid phosphatase (APH) assay, while apoptosis induction was evaluated by Annexin V/propidium iodide method. Compound 8c bearing p-methyl benzyl moiety on the triazole ring exhibited the highest MET inhibitory capacity among tested agents that was further confirmed by western blot findings. Derivatives 8c and 8h exhibited considerable antiproliferative effects against all tested cell lines, with more inhibitory effects against MET-positive cells with IC50 values as low as 6.1 μM. These two agents also significantly suppressed cell growth in spheroid cultures and induced apoptosis in MET overexpressing AsPC-1 cells. Moreover, among a panel of 24 major oncogenic kinases, the PDGFRA kinase was identified as a target of 8c and 8h compounds. The docking study results of compounds 8c and 8h were in agreement with experimental findings. The results of the present study suggest that quinazoline derivatives bearing 1,2,3-triazole moiety may represent promising targeted anticancer agents.

Novel spiroindoline quinazolinedione derivatives as anticancer agents and potential FLT3 kinase inhibitors

Despite considerable recent progress in therapeutic strategies, cancer still remains one of the leading causes of death. Molecularly targeted therapies, in particular those focused on blocking receptor tyrosine kinases have produced promising outcomes in recent years. In this study, a new series of spiro[indoline-3,2'-quinazoline]-2,4'(3'H)-dione derivatives (5a-5l) were synthesized and evaluated as potential kinase inhibitors with anticancereffects. The anti-proliferative activity was measured by MTT assay, while the cell cycle was studied using flow cytometry. Moreover, kinase inhibition profiles of the most promising compounds were assessed against a panel of 25 oncogenic kinases. Compounds 5f,5g,5i, and 5jshowed anti-proliferative effect against EBC-1, A549, and HT-29 solid tumor models in addition to leukemia cell line K562. In particular, compound 5f, bearing 4-methylphenyl pendant on the isatin ring displayed considerable potency with IC₅₀ values of 2.4 to 13.4 μM against cancer cells. The most potent derivatives also altered the distribution of cells in different phases of cell cycle and increased the sub-G1 phase cells in K562 cells. Moreover, kinase inhibition assays identified FLT3 kinase was as the primary targetof these derivatives. Compound 5f at 25 μM concentration showed inhibitory activities of 55% and 62% against wild-type FLT3 and its mutant, D835Y, respectively. Finally, the docking and simulation studies revealed the important interactions of compound 5f with wild type and mutant FLT3. The results of this study showed that some novel spiroindoline quinazolinedione compounds could be potential candidates for further development as novel targeted anticancer agents.

Reassessing the molecular structures of some previously isolated abietane diterpenoids with a naphthalene moiety and the structure-activity relationship (SAR) of quinone diterpenoids

Crystals of previously described para-naphthoquinone abietane diterpenoids 12,16-dideoxy-aegyptinone B and 12-deoxy-salvipisone were obtained from Zhumeria majdae Rech.f. & Wendelbo. However, single-crystal X-ray diffraction analysis followed by reinterpretation of their NMR data revealed that their structures require revision, and they should be revised to the two ortho-naphthoquinones, zhumerianone C and aethiopinone, respectively. Interestingly, a further search through literature revealed that there were more of such cases, in which differentiation between the ortho-/para-orientation had not been carried out correctly in the structure elucidation of naphthalene containing abietane diterpenoids. Therefore, in the current study, we pointed out some 1D and 2D NMR generalizations that would help the unambiguous deduction of the ortho-/para-orientation of naphthalene containing abietanes and revised the structure of some previously described compounds accordingly. Based on these generalizations, structures of sibiriquinones A and B, sahandinone, and sahandone were revised to the known structures 1,2-didehydromiltirone, miltirone, saprorthoquinone, and sahandone B, respectivelyand tebesinone B, arucadiol, and sahandol II were revised to three undescribed structures. It was also proposed that structures of palmitoyl arucadiol and compounds with the salvifolane skeleton need revision. Furthermore, these structure revisions shed light on the structure-activity relationship of the quinone diterpenoids, approving that the ortho-quinone is the critical structural component for cytotoxicity in these compounds.

Phytochemical Analysis and Biological Activity of Salvia compressa Vent

Background

Salvia extracts have various biological activities and are rich sources of bioactive metabolites.

Objectives

We identified five phytochemicals from S. compressa extract and assessed its biological properties.

Methods

The plant's shoots were extracted using dichloromethane, and the constituents were isolated using column chromatography. High-resolution NMR spectroscopy characterized the chemical structures of the compounds (1 - 5). The cytotoxic effect of the extract was examined against MCF-7 cells by MTT reduction assay, while cisplatin was tested as a reference cytotoxic compound. The antibacterial activity was assessed using nutrient broth micro-dilution (NBMD), and chloramphenicol was used as the positive control.

Results

Citrostadienol (1), β-sitosterol (2), two glyceride esters of linolenic, linoleic, and palmitic acids (3, 4), and geraniol (5) were isolated from S. compressa for the first time. The extract showed activity against MCF-7 breast cancer cells and reduced cell viability to 68.2 ± 13.1% compared to the control drug at the concentration of 50 µg/mL, while it was not active against seven test bacteria.

Conclusions

The anti-complementary activity of the isolated steroids suggests S. compressa for future anti-inflammatory research.

Discovery of anticancer agents with c-Met inhibitory potential by virtual and experimental screening of a chemical library

c-Met receptor tyrosine kinase has recently emerged as an important target with therapeutic implications in pancreatic cancer. In this study, we carried out a docking virtual screening on an in-house library of 441 synthesized compounds and selected the compounds with the best interactions with the c-Met protein to be subjected to experimental tests. Ten compounds belonging to 3 different classes of chemical structures were selected for this purpose and their antiproliferative effects were studied against 4 pancreatic ductal adenocarcinoma (PDAC) cell lines including AsPC-1, Suit-2, Panc-1 and Mia-Paca-2 cells, primary PDAC cells and also c-Met amplified EBC-1 cell line by sulforhodamine-B assay. Apoptosis induction was examined by Hoechst 33258 staining and annexin V-FITC/propidium iodide flow cytometric assay. The best compound was also assayed in three-dimensional cultures of AsPC-1 cells and its c-Met inhibitory potential was studied by immunoblotting and a homogenous time resolved fluorescence (HTRF) assay. The compound with a phenanthrotriazine hydrazinyl scaffold bearing nitrophenyl pendant (PhTH) was the most active derivative, with IC₅₀ values in the range of 5-8 μM. This compound exerted antiproliferative effect against AsPC-1 cells also in the presence of hepatocyte growth factor (HGF). PhTH induced apoptosis, dose-dependently inhibited spheroid growth, inhibited c-Met activity in cell-free HTRF assay and also inhibited the phosphorylation of c-Met and its downstream effector ERK1/2 in AsPC-1 cells. Molecular docking and dynamics simulation and MM-PBSA analysis confirmed close interactions of PhTH with c-Met kinase domain. Some of the tested compounds in this study seem to be potential c-Met inhibitors with promising activities against PDAC cells.

Cinnamomum verum J. Presl. Bark essential oil: in vitro investigation of anti-cholinesterase, anti-BACE1, and neuroprotective activity

Background

Cinnamomum verum J. Presl. (Lauraceae), Myrtus communis L. (Myrtaceae), Ruta graveolens L. (Rutaaceae), Anethum graveolens L. (Apiaceae), Myristica fragrans Houtt. (Myristicaceae), and Crocus sativus L. (Iridaceae) have been recommended for improvement of memory via inhalation, in Iranian Traditional Medicine (ITM). In this respect, the essential oils (EOs) from those plants were obtained and evaluated for cholinesterase (ChE) inhibitory activity as ChE inhibitors are the available drugs in the treatment of Alzheimer’s disease (AD).

Methods

EOs obtained from the plants under investigation, were evaluated for their potential to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in vitro based on the modified Ellman’s method. The most potent EO was candidate for the investigation of its beta-secretase 1 (BACE1) inhibitory activity and neuroprotectivity.

Results

Among all EOs, C. verum demonstrated the most potent activity toward AChE and BChE with IC50 values of 453.7 and 184.7 µg/mL, respectively. It also showed 62.64% and 41.79% inhibition against BACE1 at the concentration of 500 and 100 mg/mL, respectively. However, it depicted no neuroprotective potential against β-amyloid (Aβ)-induced neurotoxicity in PC12 cells. Also, identification of chemical composition of C. verum EO was achieved via gas chromatography-mass spectrometry (GC-MS) analysis and the major constituent; (E)-cinnamaldehyde, was detected as 68.23%.

Conclusion

Potent BChE inhibitory activity of C. verum EO can be considered in the development of cinnamon based dietary supplements for the management of patients with advanced AD.

Study of the anticancer effect of new quinazolinone hydrazine derivatives as receptor tyrosine kinase inhibitors

The advent of novel receptor tyrosine kinase inhibitors has provided an important therapeutic tool for cancer patients. In this study, a series of quinazolinone hydrazide triazole derivatives were designed and synthesized as novel MET (c-MET) receptor tyrosine kinase inhibitors. The antiproliferative effect of the synthesized compounds was examined against EBC-1, A549, HT-29 and U-87MG cells by MTT assay. MET kinase inhibitory effect was tested by a Homogenous Time Resolved Fluorescence (HTRF) assay. The antiproliferative effect of compounds in a three-dimensional spheroid culture was studied by acid phosphatase (APH) assay, while apoptosis induction was examined by Hoechst 33258 staining. We found that compound CM9 bearing p-bromo benzyl pendant inhibited MET kinase activity at the concentrations of 10-50 μM (% Inhibition = 37.1-66.3%). Compound CM9 showed antiproliferative effect against cancer cells, in particular lung cancer cells with MET amplification (EBC-1) with an IC50 value of 8.6 μM. Moreover, this derivative inhibited cell growth in spheroid cultures in a dose-dependent manner and induced apoptosis in cancer cells. Assessment of inhibitory effect of CM9 against a panel of 18 different protein kinases demonstrated that this compound also inhibits ALK, AXL, FGFR1, FLT1 (VEGFR1) and FLT4 (VEGFR3) more than 50% at 25 μM. Finally, molecular docking and dynamics simulation corroborated the experimental findings and showed critical structural features for the interactions between CM9 and target kinases. The findings of this study present quinazolinone hydrazide triazole derivatives as kinase inhibitors with considerable anticancer effects.

Targeted co‐delivery of paclitaxel and anti P‐gp shRNA by low molecular weight PEI decorated with L‐3,4‐dihydroxyphenylalanine

Co-delivery of small chemotherapeutic molecules and nucleic acid materials via targeted carriers has attracted great attention for treatment of resistant tumors and reducing adverse effects. In this study, a targeted carrier for co-delivery was prepared based on low-molecular weight polyethylenimine (LMW PEI). Paclitaxel (PTX) was covalently conjugated onto PEI via a succinate linker. The PEI conjugate was decorated with L-DOPA in order to target large neutral amino acid transporter-1 (LAT-1) that is over-expressed on various cancer cells. This PEI conjugate was complexed with human ABCB1 shRNA plasmid to down-regulate the expression of P-glycoprotein, as one of the major efflux pumps inducing resistance against chemotherapeutics. The formation of PEI conjugate enhanced the solubility of PTX and resulted in the condensation and protection of plasmid DNA in nanosized polyplexes. The results of targeted delivery into the cells demonstrated that PEI conjugate transferred the payloads to the cells over-expressing LAT-1 transporter, while the biological effects on the cells lacking the transporter was negligible. Also, shRNA-mediated down-regulation of P-gp led to the increase of toxic effects on the cells over-expressing P-gp. This study suggests a promising approach for co-delivery of small molecules and nucleic acid materials in a targeted manner for cancer therapy.

Synthesis and application of the fluorescent furan and imidazole probes for selective in vivo and in vitro cancer cell imaging

Development of imaging probes for identification of tumors in the early stages of growth can significantly reduce the tumor-related health hazards and improve our capacity for treatment of cancer. In this work, three different furan and imidazole fluorescent derivatives abbreviated as Cyclo X, SAC and SNO are introduced for in vivo and in vitro imaging of cancer cells. The fluorescence quantum yield values were 0.226, 0.400 and 0.479 for Cyclo X, SAC and SNO, respectively. The excitation and emission wavelengths of maximum intensity were (360, 452), (350, 428) and (350, 432) nm for Cyclo X, SAC and SNO, respectively. The MTT reduction assay was used to estimate the cytotoxic activity of the proposed derivatives against HT-29 (cancer) and Vero (normal) cell lines. Cyclo X showed no cytotoxic effect, while SAC and SNO showed significantly higher cytotoxicity against the tested cell lines than cisplatin as a well-known anticancer drug. In vitro fluorescence microscopic images obtained using HT-29 cells showed that Cyclo X produced very bright images. The in vivo cancer cell imaging using 4T1 tumor-bearing mice revealed that Cyclo X is selectively accumulated in the tumor without distribution in the mice body organs. The spectral and structural stability, large Stokes shift, non-cytotoxicity and high level of selectivity for in vivo imaging are properties that make Cyclo X a suitable candidate to be used for long-term monitoring of cancer cells.

Prospects of targeting PI3K/AKT/mTOR pathway in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) has one of the worst prognoses among all malignancies. PI3K/AKT/mTOR signaling pathway, a main downstream effector of KRAS is involved in the regulation of key hallmarks of cancer. We here report that whole-genome analyses demonstrate the frequent involvement of aberrant activations of PI3K/AKT/mTOR pathway components in PDAC patients and critically evaluate preclinical and clinical evidence on the application of PI3K/AKT/mTOR pathway targeting agents. Combinations of these agents with chemotherapeutics or other targeted therapies, including the modulators of cyclin-dependent kinases, receptor tyrosine kinases and RAF/MEK/ERK pathway are also examined. Although human genetic studies and preclinical pharmacological investigations have provided strong evidence on the role of PI3K/AKT/mTOR pathway in PDAC, clinical studies in general have not been as promising. Patient stratification seems to be the key missing point and with the advent of biomarker-guided clinical trials, targeting PI3K/AKT/mTOR pathway could provide valuable assets for treatment of pancreatic cancer patients.

Acenaphthotriazine thio-triazole derivatives as anti-cancer agents triggering cell cycle arrest in breast cancer cells

Background:

Cancer is one of the most devastating diseases, affecting the lives of millions of people around the world

Introduction:

A series of acenaphtho[1,2-e][1,2,4]triazine containing different thiomethyl-1,2,3-triazole derivatives were designed based on a fragment-based and molecular hybridization approach as anti-cancer agents.

Method:

Designed compounds were synthesized using cycloaddition condensation followed by click reaction. Cytotoxicity of prepared compounds was evaluated by MTT reduction assay against four different cancer cell lines.

Result:

The biological evaluation indicated that derivative 6d with para-fluorobenzyl moiety was the most active cytotoxic agent with IC50 values of 70.1, 12.8, 41.5, and 16.0 µM against K562, MOLT-4, HT-29, and MCF-7 cells, respectively. Cell cycle analysis showed that acenaphtho triazine derivatives could induce G0/G1 phase arrest in MCF-7 breast cancer cells.

Conclusion:

Synthesized derivatives can be ideal candidates for further exploration as anti-cancer agents

Cytotoxic furanosesquiterpenoids and steroids from Ircinia mutans sponges

CONTEXT

Ircinia mutans Wilson (Irciniidae) is a sponge with antimicrobial and cytotoxic constituents.

OBJECTIVE

Our objective was to characterise the cytotoxic constituents of two seasonal collections of I. mutans.

MATERIALS AND METHODS

The sponges were extracted in methanol-dichloromethane and their constituents were purified and characterised using column chromatography, GC-MS, 1 D and 2 D NMR. Anti-proliferative activities of the compounds, were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay (0.25-100 μg/mL, 72 h) against leukaemia (MOLT-4), breast (MCF-7) and colon cancer (HT-29) human cells.

RESULTS

Three furanosesquiterpoids; furodysin (1), ent-furodysinin (2) and furoircin (3) and ten sterols were characterised in I. mutans, for the first time. Cholesterol (4), cholesta-5, 7-dien-3β-ol (5) and ergosterol (6) were determined in the sponge from the winter collections, while cholesta-5, 22-dien-3β-ol (7), 24-methyldesmosterol (8), campesterol (9), stigmasterol (10), γ-ergostenol (11), chondrillasterol (12) and γ-sitosterol (13) were detected in the summer samples. The steroids from the winter collection exhibited cytotoxic activity with IC₅₀ values of 13.0 ± 0.9, 11.1 ± 1.7 and 1.1 ± 0.4 µg/mL, against the mentioned cancer cell lines, respectively, while those from the summer sample, showed greater activity, IC₅₀ = 1.1 ± 0.2 μg/mL against MOLT-4. The purified steroids showed potent MOLT-4 cytotoxic activity, IC₅₀ values = 2.3-7.8 µg/mL.

DISCUSSION AND CONCLUSION

The present study suggests that I. mutans is a rich source of cytotoxic steroids, and introduces 3 as new natural product. Considering the high cytotoxic activity of the steroids, these structures could be candidates for anticancer drug development in future research.

Imino-2H-Chromene Based Derivatives as Potential Anti-Alzheimer's Agents: Design, Synthesis, Biological Evaluation and in Silico Study

A new series of imino-2H-chromene derivatives were rationally designed and synthesized as novel multifunctional agents against Alzheimer's disease. A set of phenylimino-2H-chromenes as well as the newly synthesized iminochromene derivatives were evaluated as BACE1, acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) inhibitors. The results indicated that among the iminochromene set, 10c bearing fluorobenzyl moiety was the most potent BACE1 inhibitor with an IC₅₀ value 6.31 μM. In vitro anti-cholinergic activities demonstrated that compound 10a bearing benzyl pendant was the best inhibitor of AChE (% inhibition at 30 μM=24.4) and BuChE (IC₅₀ =3.3 μM). Kinetic analysis of compound 10a against BuChE was also performed and showed a mixed-type inhibition pattern. The neuroprotective assessment revealed that compound 11b, a phenylimino-2H-chromene derivative with hydroxyethyl moiety, provided 32.3 % protection at 25 μM against Aβ-induced PC12 neuronal cell damage. In addition, docking and simulation studies of the most potent compounds against BACE1 and BuChE confirmed the experimental results.

Cytotoxic abietane-type diterpenoids from roots of Salvia spinosa and their in Silico pharmacophore modeling

The roots of Salvia spinosa L. (Lamiaceae) were extracted with hexane, dichloromethane (DCM) and ethyl acetate. The DCM extract exhibited cytotoxic activity (IC₅₀ 32.7 µg/mL) against MFC-7 breast cancer cell line in MTT colorimetric bioassay. Ferruginol (1), taxodione (2), 12-deoxy-6-hydroxy-6,7-dehydroroyleanone (3), 14-deoxycoleon U (4), 15-deoxyfuerstione (5) and taxodone (6) were isolated from the DCM roots extract. Their structures were elucidated by a combination of spectroscopic analyses including EIMS and ¹H- and ¹³C NMR spectra. The cytotoxicity of compound 3 was determined against MCF-7 and K562 cell lines and compared with the other compounds. A pharmacophore model was built based on potent input compounds to resolve important pharmacophore features responsible for cytotoxic activity of the isolated compounds.

Synthesis and evaluation of novel arylisoxazoles linked to tacrine moiety: in vitro and in vivo biological activities against Alzheimer's disease

Alzheimer's disease (AD) is now ranked as the third leading cause of death after heart disease and cancer. There is no definite cure for AD due to the multi-factorial nature of the disease, hence, multi-target-directed ligands (MTDLs) have attracted lots of attention. In this work, focusing on the efficient cholinesterase inhibitory activity of tacrine, design and synthesis of novel arylisoxazole-tacrine analogues was developed. In vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition assay confirmed high potency of the title compounds. Among them, compounds 7l and 7b demonstrated high activity toward AChE and BChE with IC₅₀ values of 0.050 and 0.039 μM, respectively. Both compounds showed very good self-induced Aβ aggregation and AChE-induced inhibitory activity (79.4 and 71.4% for compound 7l and 61.8 and 58.6% for compound 7b, respectively). Also, 7l showed good anti-BACE1 activity with IC₅₀ value of 1.65 µM. The metal chelation test indicated the ability of compounds 7l and 7b to chelate biometals (Zn²⁺, Cu²⁺, and Fe²⁺). However, they showed no significant neuroprotectivity against Aβ-induced damage in PC12 cells. Evaluation of in vitro hepatotoxicity revealed comparable toxicity of compounds 7l and 7b with tacrine. In vivo studies by Morris water maze (MWM) task demonstrated that compound 7l significantly reversed scopolamine-induced memory deficit in rats. Finally, molecular docking studies of compounds 7l and 7b confirmed establishment of desired interactions with the AChE, BChE, and BACE1 active sites.

Dammarane-type triterpenoid saponins from Salvia russellii Benth

Three undescribed dammarane-type saponins, russelliinosides A-C, together with a common sterol (β-sitosterol), an abietane diterpenoid (18-hydroxyferruginol), two oleane triterpenoids (daturaolone and oleanolic acid), an ursane triterpenoid (ursolic acid) as well as three 5-hydroxyflavones (cirsimaritin, eupatorin, and salvigenin) were isolated from a dichloromethane extract of the aerial parts of Salvia russellii Benth. The chemical structures of the aforementioned compounds were characterized, using detailed spectroscopic analyses, including high-resolution mass spectrometry and 1D and 2D NMR (1H-1H COSY, TOCSY, HSQC, HMBC and NOESY) spectroscopy as well as physicochemical properties. Cytotoxic effects of S. russellii extract and the three isolated russelliinosides were tested against MCF-7 human breast and A549 lung cancer, as well as non-cancer NIH/3T3 cells using MTT reduction assay. Russelliinosides A and B exhibited cytotoxic activities with IC50 values of 7.1 and 30.7 μg/ml against MCF-7 and 33.9 and 69.4 μg/ml against A549 cells, respectively, while russelliinoside C did not show cytotoxicity against cancer cells. On the other hand, russelliinoside A showed an IC50 value of 31.5 μg/ml against NIH/3T3 cells, while russelliinosides B and C had no effect on the viability of these non-cancer cells.

Combination of HGF/MET-targeting agents and other therapeutic strategies in cancer

MET receptor has emerged as a druggable target across several human cancers. Agents targeting MET and its ligand hepatocyte growth factor (HGF) including small molecules such as crizotinib, tivantinib and cabozantinib or antibodies including rilotumumab and onartuzumab have proven their values in different tumors. Recently, capmatinib was approved for treatment of metastatic lung cancer with MET exon 14 skipping. In this review, we critically examine the current evidence on how HGF/MET combination therapies may take advantage of synergistic effects, overcome primary or acquired drug resistance, target tumor microenvironment, modulate drug metabolism or tackle pharmacokinetic issues. Preclinical and clinical studies on the combination of HGF/MET-targeted agents with conventional chemotherapeutics or molecularly targeted treatments (including EGFR, VEGFR, HER2, RAF/MEK, and PI3K/Akt targeting agents) and also the value of biomarkers are examined. Our deeper understanding of molecular mechanisms underlying successful pharmacological combinations is crucial to find the best personalized treatment regimens for cancer patients.

Novel Cytotoxic Phenanthro-triazine-3-thiol Derivatives as Potential DNA Intercalators and Bcl-2 Inhibitors

Novel phenanthro-triazine-3-thiol derivatives were designed as potential DNA intercalators and Bcl-2 inhibitors. After being synthesized, the compounds were evaluated for their cytotoxic activity against MOLT-4 (human acute lymphoblastic leukemia) and MCF-7 (human breast adenocarcinoma) cells by MTT assay. P1 (bearing hydrogen substitution) was the most potent derivative against MOLT-4 with an IC₅₀ value of 7.1 ± 1.1 μM, whereas P11 (bearing phenyl substitution) demonstrated considerable cytotoxicity against MCF-7 with an IC₅₀ value of 15.4 ± 2.9 μM. Compounds P7, P8, P14 and P15 exhibited moderate cytotoxic effects. Furthermore, to confirm the potential DNA intercalation and Bcl-2 inhibitory activities of phenanthro-triazine scaffolds, molecular docking analysis was performed. Molecular docking studies indicated that these compounds not only bind to DNA by intercalation mainly through stacking interactions but also are well accommodated in the active site of Bcl-2. Therefore, P1 and P11 having phenanthro-triazine-3-thiol scaffold could be presented as cytotoxic agents with dual DNA intercalation and Bcl-2 inhibitory activities.

Phenanthrotriazine Derivatives Containing Arylidine Hydrazone Moieties as Novel Potential c-Met Inhibitors with Anticancer Effect

Cancer is the second cause of death in the world and the discovery of novel anticancer agents is of vital importance to provide better therapeutic options for cancer patients. In this study, a new series of 12 arylidene hydrazone phenanthrotriazine derivatives were designed, synthesized, and tested in-vitro for antiproliferative activity against three cancer cell lines including colorectal cancer (HT-29), breast cancer (MCF-7) and leukemia (MOLT-4) cells and also against Vero normal cells. The effect of derivatives on cell cycle and apoptosis induction were studied by flow cytometric propidium iodide/RNase assay and Hoechst 33258 staining, respectively, while docking analysis was used to investigate the interactions of synthesized derivatives with the c-Met receptor kinase domain. Some compounds showed considerable antiproliferative activity against tested cancer cells. The most potent derivative was 9k bearing pyrrole moiety with IC₅₀ values of 14.3, 4.7 and 1.7 µM against HT-29, MCF-7 and MOLT-4 cells, respectively, while it showed negligible activity against Vero normal cells (IC₅₀: 95.4 µM). Derivatives bearing 2-nitrophenyl (9g), 4-cyanophenyl (9j), pyrrole (9k), and thiophene (9l) moieties induced G0/G1 cell cycle arrest and also apoptosis at higher doses in MCF-7 cells. Docking study showed that the phenanthrotriazine backbone form H-bond interactions with Asn1209, while phenyl moieties of the pendants generate different hydrophobic interactions with the Asp1164 and Asp1231 residues of c-Met. In conclusion, phenanthrene 1,2,4-triazines, especially the ones with less influence on normal cells, may constitute promising compounds for the discovery of antiproliferative agents with potential c-Met inhibitory capacity.

Discovery of a Potent Dual Inhibitor of Acetylcholinesterase and Butyrylcholinesterase with Antioxidant Activity that Alleviates Alzheimer-like Pathology in Old APP/PS1 Mice

The combination of the scaffolds of the cholinesterase inhibitor huprine Y and the antioxidant capsaicin results in compounds with nanomolar potencies toward human acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) that retain or improve the antioxidant properties of capsaicin. Crystal structures of their complexes with AChE and BChE revealed the molecular basis for their high potency. Brain penetration was confirmed by biodistribution studies in C57BL6 mice, with one compound (5i) displaying better brain/plasma ratio than donepezil. Chronic treatment of 10 month-old APP/PS1 mice with 5i (2 mg/kg, i.p., 3 times per week, 4 weeks) rescued learning and memory impairments, as measured by three different behavioral tests, delayed the Alzheimer-like pathology progression, as suggested by a significantly reduced Aβ42/Aβ40 ratio in the hippocampus, improved basal synaptic efficacy, and significantly reduced hippocampal oxidative stress and neuroinflammation. Compound 5i emerges as an interesting anti-Alzheimer lead with beneficial effects on cognitive symptoms and on some underlying disease mechanisms.

Novel N-benzylpiperidine derivatives of 5-arylisoxazole-3-carboxamides as anti-Alzheimer's agents

The complex pathophysiology of Alzheimer's disease (AD) has prompted researchers to develop multitarget-directed molecules to find an effective therapy against the disease. In this context, a novel series of N-(1-benzylpiperidin-4-yl)-5-arylisoxazole-3-carboxamide derivatives were designed, synthesized, and evaluated against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). In vitro biological evaluation demonstrated that compound 4e was the best AChE (IC₅₀  = 16.07 μM) and BuChE inhibitor (IC₅₀  = 15.16 μM). A kinetic study of 4e was also conducted, which presented a mixed-type inhibition for both enzymes. Molecular docking studies revealed that compound 4e fitted well into the active sites of AChE and BuChE, forming stable and strong interactions with key residues Glu199, Trp84, Asp72, Tyr121, and Phe288 in AChE and His438, Trp82, Ala328, Tyr332, Phe329, Thr120, and Pro285 in BuChE. Besides, the inhibition of BACE1 by 4e and the biometal chelation activity of 4e were measured. The neuroprotective assessment revealed that 4e exhibited 23.2% protection at 50 µM toward amyloid-beta-induced PC12 neuronal cells. Overall, this study exhibited that compound 4e was a promising compound targeting multiple factors associated with AD.

Paclitaxel-loaded polypeptide-polyacrylamide nanomicelles overcome drug-resistance by enhancing lysosomal membrane permeability and inducing apoptosis

The aim of the current project was to investigate the in vitro properties of Paclitaxel (PTX)-loaded pHPMA_5kD -pHis_5kD -pLeu_3kD nanomicelles (NMs) on multidrug resistance cell line. Circular dichroism analysis was done to investigate the effect of pH on the secondary structure of the copolymer. Cytotoxicity assay together with fluorescence imaging and flow cytometry were performed to get an insight about toxicity and cellular uptake mechanism of NMs. Acridine orange assay, rhodamine 123 (Rh123) accumulation assay, and apoptosis analysis were conducted for further investigation. It was found that the secondary structure of the copolymer changed in response to pH, PTX-loaded NMs had higher cytotoxicity on both drug-sensitive (MES-SA and MCF-7) and multidrug resistant cells (MES-SA/DX5) compared to free PTX, and interestinly free copolymer inhibited the growth of MES-SA/DX5 cells while it was nontoxic on drug-sensitive cells. Moreover, the copolymer was able to induce lysosome membrane permeation and increase Rh123 accumulation inside cells indicating inhibition of the P-gp efflux pumps. Finally, apoptosis was strongly induced in MES-SA/DX5 cells upon treatment with PTX-loaded NMs. It can be concluded that the designed hybrid copolymer is a good candidate for in vivo assay and developing a powerful system against multidrug resistance tumors.

Thieno[2,3-b]pyridine amines: Synthesis and evaluation of tacrine analogs against biological activities related to Alzheimer's disease

In search of safer tacrine analogs, various thieno[2,3-b]pyridine amine derivatives were synthesized and evaluated for their inhibitory activity against cholinesterases (ChEs). Among the synthesized compounds, compounds 5e and 5d showed the highest activity towards acetylcholinesterase and butyrylcholinesterase, with IC₅₀ values of 1.55 and 0.23 µM, respectively. The most active ChE inhibitors (5e and 5d) were also candidates for further complementary assays, such as kinetic and molecular docking studies as well as studies on inhibitory activity towards amyloid-beta (βA) aggregation and β-secretase 1, neuroprotectivity, and cytotoxicity against HepG2 cells. Our results indicated efficient anti-Alzheimer's activity of the synthesized compounds.

Cytotoxic Activity and DNA Binding Property of New Aminopyrimidine Derivatives

Background:

Chromene and anilinopyrimidine heterocyclics are attractive anticancer compounds that have inspired many researchers to design novel derivatives bearing improved anticancer activity.

Methods:

A series of pyrimidine-fused benzo[f]chromene derivatives 6a-x were synthesized as anticancer hybrids of 1H-benzo[f]chromenes and anilinopyrimidines. The inhibitory activity of the synthesized compounds 6a-x against cell viability of human chronic myelogenous leukemia (K562), human acute lymphoblastic leukemia (MOLT-4) and human breast adenocarcinoma (MCF-7) cell lines was evaluated using MTT assay. The interaction of the most promising compound with calf-thymus DNA was also studied using spectrometric titrations and Circular Dichroism (CD) spectroscopy.

Results:

Most compounds showed promising activity against tested cell lines. Among them, 2,4- dimethoxyanilino derivative 6g exhibited the best profile of activity against tested cell lines (IC50s = 1.6-6.1 μM) with no toxicity against NIH3T3 normal cell (IC50 >200 μM). The spectrometric studies exhibited that compound 6g binds to DNA strongly and may change DNA conformation significantly, presumably via a groove binding mechanism.

Conclusion:

The results of this study suggest that the prototype compound 6g can be considered as a novel lead compound for the design and discovery of novel anticancer agents.

Design and Synthesis of Novel Arylisoxazole-Chromenone Carboxamides: Investigation of Biological Activities Associated with Alzheimer's Disease

A novel series of hybrid arylisoxazole-chromenone carboxamides were designed, synthesized, and evaluated for their cholinesterase (ChE) inhibitory activity based on the modified Ellman's method. Among synthesized compounds, 5-(3-nitrophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide depicted the most acetylcholinesterase (AChE) inhibitory activity (IC₅₀ =1.23 μm) and 5-(3-chlorophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide was found to be the most potent butyrylcholinesterase (BChE) inhibitor (IC₅₀ =9.71 μm). 5-(3-Nitrophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide was further investigated for its BACE1 inhibitory activity as well as neuroprotectivity and metal chelating ability as important factors involved in onset and progress of Alzheimer's disease. It could inhibit BACE1 by 48.46 % at 50 μm. It also showed 6.4 % protection at 25 μm and satisfactory chelating ability toward Zn²⁺ , Fe²⁺ , and Cu²⁺ ions. Docking studies of 5-(3-nitrophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide and 5-(3-chlorophenyl)-N-{4-[(2-oxo-2H-1-benzopyran-7-yl)oxy]phenyl}-1,2-oxazole-3-carboxamide confirmed desired interactions with those amino acid residues of the AChE and BChE, respectively.

Novel small molecule therapeutic agents for Alzheimer disease: Focusing on BACE1 and multi-target directed ligands

Alzheimer's Disease (AD) is a progressive neurodegenerative disorder that effects 50 million people worldwide. In this review, AD pathology and the development of novel therapeutic agents targeting AD were fully discussed. In particular, common approaches to prevent Aβ production and/or accumulation in the brain including α-secretase activators, specific γ-secretase modulators and small molecules BACE1 inhibitors were reviewed. Additionally, natural-origin bioactive compounds that provide AD therapeutic advances have been introduced. Considering AD is a multifactorial disease, the therapeutic potential of diverse multi target-directed ligands (MTDLs) that combine the efficacy of cholinesterase (ChE) inhibitors, MAO (monoamine oxidase) inhibitors, BACE1 inhibitors, phosphodiesterase 4D (PDE4D) inhibitors, for the treatment of AD are also reviewed. This article also highlights descriptions on the regulator of serotonin receptor (5-HT), metal chelators, anti-aggregants, antioxidants and neuroprotective agents targeting AD. Finally, current computational methods for evaluating the structure-activity relationships (SAR) and virtual screening (VS) of AD drugs are discussed and evaluated.

Study of the mechanism of action, molecular docking, and dynamics of anticancer terpenoids from Salvia lachnocalyx

Among specialized metabolites, terpenoids are well-known for their cytotoxic activity. Several of them have been isolated from sage plants and assayed for their potential therapeutic use against cancer. In this study, we report the effects of three potent anticancer terpenoids previously isolated from Salvia lachnocalyx, including geranyl farnesol (1), sahandinone (2), and 4-dehydrosalvilimbinol (3) on cancer cell cycle alterations and reactive oxygen species (ROS) production. Interactions of compounds 1-3 with topoisomerase I were also investigated by using molecular docking and dynamics simulation. Accumulation of cells in sub-G1 phase of the cell cycle indicated that all tested compounds induce apoptosis in MOLT-4 cancer cells. Measurement of ROS production demonstrated that this mechanism is not involved in the induction of apoptosis. We suggest topoisomerase I inhibition as the mechanism of cytotoxic activity of compounds 1-3 based on docking and molecular dynamics (MD) calculations. These natural terpenoids could be considered as good candidates for further development as anticancer agents.

Design and Synthesis of Novel 1-hydroxy-2,4,5-triaryl Imidazole Derivatives as Anti-cytokine Agents

Among recent advances in the identification of anti-inflammation agents, anti-cytokines (like Interleukin-1), related to p38 MAPK families play an important role; Here in we designed new effective and low toxic anti-cytokine agents based on 1-hydroxy-2,4,5-triaryl imidazole derivatives. The reaction of oximoinoketone intermediate with ten different aromatic aldehyde and ammonium acetate in refluxing acetic acid condition give imidazole derived product, the IL-1β inhibitory assay were performed on Human PBMCs (peripheral blood mononuclear cells) using an enzyme-linked immunosorbent assay (ELISA) kit and then in computational part the binding mode of the best compound was accomplished by docking in Crystal structure of p38 MAP kinase (PDB ID: 1A9U) compared with SB202190 as standard drug. All compounds were synthesized and evaluated in biological assay showing the inhibitory activity from 28% to 82% compared to SB202190 and binding mode analysis revealed that the hydrogen-bond interactions with residues (Met109, Val30) were key point in inhibitor binding. Compound 5g clearly proved the best inhibitory action and could be further utilized for designing newer anti-cytokine agents and p38α MAP kinase potentially inhibitory action.

Caffeic Acid Alkyl Amide Derivatives Ameliorate Oxidative Stress and Modulate ERK1/2 and AKT Signaling Pathways in a Rat Model of Diabetic Retinopathy

The purpose of this study was to examine the neuroprotective effects of caffeic acid hexyl (CAF6) and dodecyl (CAF12) amide derivatives on the early stage of retinopathy in streptozotocin-induced diabetic rats. Animals were divided in five groups (n=8/group); one group consisted of non-diabetic rats as control, while the other four were diabetic animals either non-treated or treated with CAF6, CAF12 or resveratrol intravitreally for four weeks. Retinal superoxide dismutase (SOD) activity and 8-iso-prostaglandin F_2α (iPF_2α ) levels were evaluated by an ELISA assay. Phosphorylation of ERK1/2 and AKT was determined by immunoblotting in retinal homogenates. Retinal morphology was also examined using light microscopy. Treatment with CAF6 and CAF12 increased retinal SOD activity, while it decreased iPF_2α levels in diabetic rats. Phosphorylation of ERK1/2 was increased, while AKT phosphorylation was decreased in diabetic rats compared to normal control and these alterations were significantly reversed in diabetic rats treated with CAF6 and CAF12. Furthermore, thickness of the whole retinal layer, outer nuclear layer, and ganglion cell count were decreased in diabetic rats compared to control and CAF6 and CAF12 treatments prevented these changes. CAF6 and CAF12 seem to be effective agents for treatment of diabetic retinopathy via attenuation of retinal oxidative stress and improvement of neuronal survival signaling.

Prediction of cytotoxic activity of a series of 1H-pyrrolo[2,3-b]pyridine derivatives as possible inhibitors of c-Met using molecular fingerprints

Cancer is a leading cause of death all over the world. HGF/MET signaling pathway is involved in many cancers and its inhibition has great potential as an effective therapeutic intervention. A series of 1H-pyrrolo [2,3-b]pyridine derivatives has recently been identified with cytotoxic activity, and most of them exhibited considerable potencies with IC₅₀ values under 10 µM. The present study was carried out with the specific aim to shed light upon the quantitative structure activity relationship (QSAR) to design and predict the activity of new potent inhibitors using molecular fingerprints and some 2D and 3D descriptors. The built model was statistically significant in terms of R² = 0.90 and R²_pred = 0.91 values. Fingerprint PubchemFP759 (1-chloro-2-methylbenzene) was the most effective fragment in the biological activity and just appeared in the most active compound 7j with a pIC₅₀ value of 8.0. A similarity search study was applied based on compounds 7c and 17e, with reported inhibitory activity against c-Met kinase, which showed that also other compounds could possess similar effects against c-Met enzyme. The most promising compound 7g-cl was subjected to docking and molecular dynamics simulation. Two hydrogen bonds between Lys1110, Met1160, and 7g-cl were stable during the equilibrium time range. The suggested modifications might be considered in future studies to design more efficient anticancer agents.

HGF/MET pathway aberrations as diagnostic, prognostic, and predictive biomarkers in human cancers

Cancer is a major cause of death worldwide. MET tyrosine kinase receptor [MET, c-MET, hepatocyte growth factor (HGF) receptor] pathway activation is associated with the appearance of several hallmarks of cancer. The HGF/MET pathway has emerged as an important actionable target across many solid tumors; therefore, biomarker discovery becomes essential in order to guide clinical intervention and patient stratification with the aim of moving towards personalized medicine. The focus of this review is on how the aberrant activation of the HGF/MET pathway in tumor tissue or the circulation can provide diagnostic and prognostic biomarkers and predictive biomarkers of drug response. Many meta-analyses have shown that aberrant activation of the MET pathway in tumor tissue, including MET gene overexpression, gene amplification, exon 14 skipping and other activating mutations, is almost invariably associated with shorter survival and poor prognosis. Most meta-analyses have been performed in non-small cell lung cancer (NSCLC), breast, head and neck cancers as well as colorectal, gastric, pancreatic and other gastrointestinal cancers. Furthermore, several studies have shown the predictive value of MET biomarkers in the identification of patients who gain the most benefit from HGF/MET targeted therapies administered as single or combination therapies. The highest predictive values have been observed for response to foretinib and savolitinib in renal cancer, as well as tivantinib in NSCLC and colorectal cancer. However, some studies, especially those based on MET expression, have failed to show much value in these stratifications. This may be rooted in lack of standardization of methodologies, in particular in scoring systems applied in immunohistochemistry determinations or absence of oncogenic addiction of cancer cells to the MET pathway, despite detection of overexpression. Measurements of amplification and mutation aberrations are less likely to suffer from these pitfalls. Increased levels of MET soluble ectodomain (sMET) in circulation have also been associated with poor prognosis; however, the evidence is not as strong as it is with tissue-based biomarkers. As a diagnostic biomarker, sMET has shown its value in distinguishing cancer patients from healthy individuals in prostate and bladder cancers and in melanoma. On the other hand, increased circulating HGF has also been presented as a valuable prognostic and diagnostic biomarker in many cancers; however, there is controversy on the predictive value of HGF as a biomarker. Other biomarkers such as circulating tumor DNA (ctDNA) and tumor HGF levels have also been briefly covered. In conclusion, HGF/MET aberrations can provide valuable diagnostic, prognostic and predictive biomarkers and represent vital assets for personalized cancer therapy.

Novel N-benzylpyridinium moiety linked to arylisoxazole derivatives as selective butyrylcholinesterase inhibitors: Synthesis, biological evaluation, and docking study

A novel series of N-benzylpyridinium moiety linked to arylisoxazole ring were designed, synthesized, and evaluated for their in vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities. Synthesized compounds were classified into two series of 5a-i and 5j-q considering the position of positively charged nitrogen of pyridinium moiety (3- or 4- position, respectively) connected to isoxazole carboxamide group. Among the synthesized compounds, compound 5n from the second series of compounds possessing 2,4-dichloroaryl group connected to isoxazole ring was found to be the most potent AChE inhibitor (IC₅₀ = 5.96 µM) and compound 5j also from the same series of compounds containing phenyl group connected to isoxazole ring demonstrated the most promising inhibitory activity against BChE (IC₅₀ = 0.32 µM). Also, kinetic study demonstrated competitive inhibition mode for both AChE and BChE inhibitory activity. Docking study was also performed for those compounds and desired interactions with those active site amino acid residues were confirmed through hydrogen bonding as well as π-π and π-anion interactions. In addition, the most potent compounds were tested against BACE1 and their neuroprotectivity on Aβ-treated neurotoxicity in PC12 cells which depicted negligible activity. It should be noted that most of the synthesized compounds from both categories 5a-i and 5j-q showed a significant selectivity toward BChE. However, series 5j-q were more active toward AChE than series 5a-i.

Unsymmetric dihydropyridines bearing 2-pyridyl methyl carboxylate as modulators of P-glycoprotein; synthesis and biological evaluation in resistant and non-resistant cancer cells

Multi-drug resistance (MDR) in cancer cells is often associated with overexpression of P-glycoprotein (P-gp or ABCB1 or MDR1); therefore, modulators of this transporter might be helpful in overcoming MDR. In this study, 16 novel unsymmetrical dihydropyridine (DHP) derivatives bearing 2-pyridyl methyl carboxylate at C3 and a nitroimidazole or nitrophenyl ring at C4 positions of the DHP ring were synthesized. Their cytotoxicity was tested against four human cancer cells by MTT assay. The reversal capacity of MDR was examined in P-gp overexpressing cells (MES-SA/DX5) by measuring the alteration of doxorubicin’s IC50 and performing flow cytometric determination of intracellular rhodamine 123 accumulation. The calcium channel blocking (CCB) activity, as a side effect of DHPs, was tested on the ileum of a guinea pig. Molecular docking was performed to explain the binding mode of compounds. Two derivatives, 4a and 4c, containing 4-nitrophenyl at C4 and possessing methyl (4a) and iso-propyl (4c) carboxylates at the C5 position of DHP core demonstrated superior cytotoxic and MDR reversal activities and lower CCB effect. Docking analysis confirmed the importance of the 4-nitrophenyl ring for P-gp inhibitory activity. Some of the synthesized DHP derivatives with considerable MDR reversal capacity could be promising compounds for further discovery of useful agents for management of drug resistant cancer.

Role of c-MET Inhibitors in Overcoming Drug Resistance in Spheroid Models of Primary Human Pancreatic Cancer and Stellate Cells

Pancreatic stellate cells (PSCs) are a key component of tumor microenvironment in pancreatic ductal adenocarcinoma (PDAC) and contribute to drug resistance. c-MET receptor tyrosine kinase activation plays an important role in tumorigenesis in different cancers including PDAC. In this study, effects of PSC conditioned medium (PCM) on c-MET phosphorylation (by immunocytochemistry enzyme-linked immunosorbent assay (ELISA)) and drug response (by sulforhodamine B assay) were investigated in five primary PDAC cells. In novel 3D-spheroid co-cultures of cyan fluorescence protein (CFP)-firefly luciferase (Fluc)-expressing primary human PDAC cells and green fluorescence protein (GFP)-expressing immortalized PSCs, PDAC cell growth and chemosensitivity were examined by luciferase assay, while spheroids' architecture was evaluated by confocal microscopy. The highest phospho-c-MET expression was detected in PDAC5 and its subclone sorted for "stage specific embryonic antigen-4" (PDAC5 (SSEA4)). PCM of cells pre-incubated with PDAC conditioned medium, containing increased hepatocyte growth factor (HGF) levels, made PDAC cells significantly more resistant to gemcitabine, but not to c-MET inhibitors. Hetero-spheroids containing both PSCs and PDAC5 (SSEA4) cells were more resistant to gemcitabine compared to PDAC5 (SSEA4) homo-spheroids. However, c-MET inhibitors (tivantinib, PHA-665752 and crizotinib) were equally effective in both spheroid models. Experiments with primary human PSCs confirmed the main findings. In conclusion, we developed spheroid models to evaluate PSC-PDAC reciprocal interaction, unraveling c-MET inhibition as an important therapeutic option against drug resistant PDAC.

Synthesis and Biological Activity of Some Benzochromenoquinolinones: Tacrine Analogs as Potent Anti-Alzheimer's Agents

Alzheimer's disease (AD) is a well-known neurodegenerative disorder affecting millions of old people worldwide and the corresponding epidemiological data emphasize the importance of the disease. As AD is a multifactorial illness, various single target directed drugs that have reached clinical trials have failed. Therefore, various factors associated with outset of AD have been considered in targeted drug discovery. In this work, various benzochromenoquinolinones were synthesized and evaluated for their cholinesterase and BACE1 inhibitory activities as well as neuroprotective and metal-chelating properties. Among the synthesized compounds, 14-amino-13-(3-nitrophenyl)-2,3,4,13-tetrahydro-1H-benzo[6,7]chromeno[2,3-b]quinoline-7,12-dione (6m) depicted the best inhibitory activity toward acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with IC₅₀ s of 0.86 and 6.03 μm, respectively. Also, the compound could inhibit β-secretase 1 (BACE1) with IC₅₀ =19.60 μm and showed metal chelating ability toward Cu²⁺ , Fe²⁺ , and Zn²⁺ . In addition, docking study demonstrated desirable interactions of compound 6m with amino acid residues characterizing AChE, BChE, and BACE1.

In vitro anti-proliferative activities of the sterols and fatty acids isolated from the Persian Gulf sponge; Axinella sinoxea

PURPOSE

Marine sponges are rich sources of anticancer metabolites. Axinella sinoxea is a less studied sponge, found in the Larak Island's waters, of the Persian Gulf. In the present study, we have explored the cytotoxic properties and chemical constituents of A. sinoxea.

METHODS

Repeated silica gel flash column chromatography of methanol extract of the Axinella sinoxea sponge, yielded fatty acid and sterol fractions. These fractions were analyzed by GC-MS and their anti-proliferative activities were evaluated by MTT assay against three human cancer cell lines including MOLT-4, MCF-7 and HT-29 as well as NIH/3 T3 fibroblast cells. The sterol-rich fractions were pooled and purified by HPLC and its sub fractions' cytotoxic activities were evaluated by MTT assay against MOLT-4 and NIH/3 T3 cells.

RESULTS

The GC-MS spectral analysis of a fraction eluted with hexane: diethyl ether (90: 10), resulted in the identification of twelve fatty acids, including five linear chain saturated fatty acids; tetrdecanoic acid (1), pentadecanoic acid (3), hexadecanoic acid (5), heptadecanoic acid (7), and octadecanoic acid (10); one branched chain isoprenoid fatty acid, 4,8,12-trimethyltridecanoic acid (2); four monoenoic fatty acids; 9-hexadecenoic acid (4), 7-methyl-6-hexadecanoic acid (6), 9-octadecenoic acid (8) and 11-octadecenoic acid (9) and two polyunsaturated fatty acids; 5,8,11,14-eicosatetraenoic acid (11) and 4,7,10,13,16,19-docosahexaenoic acid (12). Spectral analysis of a non-polar fraction eluted with hexane: diethyl ether (85: 15), resulted in the identification of eight steroids including: cholesta-5,22-dien-3β-ol (13), cholest-5-en-3β-ol (14), ergosta-5,22-dien-3β-ol (15), ergost-5-en-3β-ol (16), stigmasta-5,22-dien-3β-ol (17), γ-sitosterol (18), 33-norgorgosta-5,24(28)-dien-3β-ol (19) and stigmasta-5,24(28)-dien-3β-ol (20). Fatty acids-containing fraction was active against HT-29 cell line with IC₅₀ 26.52 ± 8.19 μg/mL, while the steroids-rich fraction was active against the three above mentioned cell lines with IC₅₀ values of 1.20 ± 0.24, 4.12 ± 0.40 and 2.47 ± 0.31 μg/mL, respectively. All of the above-mentioned fractions and sub-fractions were inactive (IC₅₀s > 50 μg/mL) when assayed against normal fibroblast cells.

CONCLUSION

The present study suggests A. sinoxea as a potential natural source of cancer chemotherapeutics. Graphical abstract Cytotxic constituents of Axinella sinoxea.

Behaviour of 9-Ethyl-9H-carbazole Hydrazone Derivatives Against Oxidant Systems

Antioxidants are helpful in prevention of several diseases related with oxidative stress including neurodegenerative disorders. In recent studies, carbazoles were given proof of promising antioxidant activities. In this article, 9-ethyl-9H-carbazole hydrazone derivatives were synthesized, characterized and their in vitro antioxidant activity and possible cytotoxic effects were investigated. Furthermore, protective effect of the synthesized derivatives against amyloid β-induced damage in PC12 neuronal cells was examined by using MTT assay. The newly synthesized carbazoles were found to have radical scavenging activity with a varying potency both in cell-free and cell-based in vitro assays. Several compounds, especially such as 3d and 3e, 3m and 3n bearing two halogen groups on the phenyl ring, were found to have cytotoxic activity. However, their cytotoxic activities were not higher than that of melatonin. Several compounds also significantly protected neuronal PC12 cells against amyloid β-induced damage, which can be defined as neuroprotective agents. (4-(2-((9-Ethyl-9H-carbazol-3-yl)methylene)hydrazinyl)benzonitrile) 3r was found as the most active compound with both radical scavenging activity and neuroprotective effects against amyloid β-induced damage. These findings might provide an alternative strategy for developing novel carbazole derivatives for management of neurodegenerative diseases, such as Alzheimer's disease.

Searching for new cytotoxic agents based on chromen-4-one and chromane-2,4-dione scaffolds

Cancer is a major cause of death worldwide and novel anticancer agents for its better management are much needed. Benzopyrone-based compounds, such as chromones, possess several distinctive chemical and biological properties, of which the cytotoxicity against cancer cells seems to be prominent. In this study, two series of compounds based on chromen-4-one (3-10) and chromane-2,4-dione (11-18) scaffolds were synthesized in moderate/high yields and evaluated for cytotoxicity against HL-60, MOLT-4, and MCF-7 cancer cells using MTT assay. In general, the compounds exhibited moderate cytotoxic effects against the cancer cell lines, among which, a superior potency could be observed against MOLT-4 cells. Chroman-2,4-dione (11-18) derivatives had overall higher potencies compared to their chromen-4-one (3-10) counterparts. Compound 13 displayed the lowest IC₅₀ values against HL-60 (IC₅₀, 42.0 ± 2.7 μM) and MOLT-4 cell lines (IC₅₀, 24.4 ± 2.6 μM), while derivative 11 showed the highest activity against MCF-7 cells (IC₅₀, 68.4 ± 3.9 μM). In conclusion, this study provides important information on the cytotoxic effects of chromone derivatives. Benzochroman-2,4-dione has been identified as a promising scaffold, which its potency can be modulated by tailored synthesis with the aim of finding novel and dissimilar anticancer compounds.