Magda F. Mohamed

Cytotoxic and Antimicrobial Evaluations of Novel Apoptotic and Anti‐Angiogenic Spiro Cyclic 2‐Oxindole Derivatives of 2‐Amino‐tetrahydroquinolin‐5‐one

A novel series of cyclic 2‐oxindole derivatives incorporating 2‐amino‐tetrahydroquinolin‐5‐one were prepared. The structures of the prepared compounds were elucidated using different spectral tools. The regio‐orientation of the reaction products was elucidated through NOE difference experiments and through using substituents on the ortho position to affect further cyclization. Antitumor and antimicrobial evaluations were performed on the prepared compounds. Most of these compounds exhibited high to moderate antimicrobial activity. With respect to the antitumor activity, the compounds showed more potent cytotoxic effect only toward the human breast cancer cell line MCF‐7. Also, we found that derivatives containing an ester group (8c, 11b, 14b, and 15b) are more active than those containing a cyanide group (8a, 11a, 14a, and 15a). Moreover, compounds 15b and 8b are the most active derivatives in this group. These two compounds showed apoptotic inhibition of the proliferation of human breast adenocarcinoma MCF‐7 cells through DNA fragmentation, induction of the tumor suppressor protein p53, induction of caspase‐9, and finally the inhibition of angiogenesis by decreasing vascular endothelial growth factor expression and secretion.

A novel adamantane thiadiazole derivative induces mitochondria-mediated apoptosis in lung carcinoma cell line

The interaction of organic compounds with apoptosis regulatory proteins is an attractive field of research because of its relevance in the development of new chemotherapeutic agents for cancer treatment. Our group designed four new adamantane thiadiazole derivatives (ATDs). The four ATDs were theoretically tested for their binding affinities to a model of an apoptosis inhibitor protein using molecular modeling. ATD-4 which interacted with the highest binding affinity was synthesized and characterized. The in vitro cytotoxicity of ATD-4 against different cancer cell lines as well as normal cell line was determined and compared with 5-fluorouracil as a standard positive control. The lung carcinoma cell line that showed the highest cytotoxic activity due to ATD-4 treatment was chosen to further study if ATD-4 can perform its cytotoxic activity through the induction of apoptosis as expected from molecular modeling. Inducing apoptosis by ATD-4 in lung carcinoma cell line was assessed by various biochemical and morphological characteristics. Biochemically: The effect of ATD-4 on cell cycle and its ability to induce apoptosis were checked through flow cytometry. Caspase-3 activity was detected by a colorimetric method. Real time-polymerase chain reaction (q-PCR) was used to detect p53, caspase-3, bcl-2 and bax gene expression. Morphologically: Changes in cell surface morphology, granulation and average surface roughness were detected using atomic force microscopy (AFM). Cell shrinkage, increase in cytoplasmic organelles, changes in mitochondrial number and morphology, chromatin condensation, membrane blebbing and formation of apoptotic bodies were detected using transmission electron microscopy (TEM). The obtained results suggest that ATD-4 exerted its antitumor activity against A549 cells through the induction of the intrinsic (mitochondrial) apoptotic pathway.

Chalcones incorporated pyrazole ring inhibit proliferation, cell cycle progression, angiogenesis and induce apoptosis of MCF7 cell line.

A Series of chalcone derivatives containing pyrazole ring was prepared and their cytotoxicity against different human cell lines, including breast (MCF-7), colon (HCT-116) liver (HEPG2) cell lines, as well as normal melanocyte HFB4 was evaluated. Two of these chalcone derivatives with different IC50 and chemical configuration were chosen for molecular studies in detail with MCF-7 cells. Our data indicated that the two compounds prohibit proliferation, angiogenesis, cell cycle progression and induce apoptosis of breast cancer cells. This inhibition is mediated by up regulation of tumor suppressor p53 associated with arrest in S-G2/M of cell cycle. This work provides a confirmation of antitumor activity of the novel chalcones and assists the development of new agents for cancer treatment.

Synthesis, characterization and antitumor activity of novel tetrapodal 1,4-dihydropyridines: p53 induction, cell cycle arrest and low damage effect on normal cells induced by genotoxic factor H2O2

Synthesis of novel tetrakis(2,6-dimethyl-4-phenyl-1,4-dihydropyridinyl)methanes 5a–d by acid-catalyzed condensation of the tetrakis-aldehydes 6a–d with eight equivalents of 3-aminobut-2-enenitrile 2 is reported. The structures of 5a–d are confirmed by different spectral tools. In vitro, cytotoxic screening assay for novel tetrapodal 1,4-dihydropyridines (5a–d) was performed on five different human cell lines (HCT116, A549, MCF7, PC3, and HEPG2). The compounds showed higher cytotoxic activity against (A549, HCT116, and MCF7) cell lines. The loss of the cytotoxic activity was observed in the case of PC3 and HEPG2 cell lines. Compound 5b showed the highest cytotoxic activity against the three lines (A549, HCT116, and MCF7). In an attempt to know the mechanism followed by the compounds to inhibit cell proliferation, compound 5b was chosen for molecular studies. Compound 5b induced apoptotic inhibition of the proliferation of human colon adenocarcinoma HCT116 cells through induction of the tumor suppressor protein p53, BAX, and through the inhibition of anti-apoptotic proteins by decreasing BCL2 gene expression using real-time PCR. Regarding cell cycle analysis, compound 5b induced G1 arrest against the three lines (MCF7, HCT116, and A549). Compound 5b has been found to reduce apoptosis of human normal melanocytes HFB4 and normal fibroblasts BHK that has been treated with genotoxic factor H2O2. Moreover, compound 5b has a potent protective effect against DNA damage, as indicated by the in vitro studying of different concentrations of 5b against two different types of healthy DNA (calf-thymus DNA and pBR322 DNA).

Molecular docking simulation and anticancer assessment on human breast carcinoma cell line using novel bis(1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile) and bis(1,4-dihydropyrazolo[4',3':5,6]pyrano[2,3-b]pyridine-6-carbonitrile) derivatives.

An efficient route for the synthesis of novel bis(1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile) derivatives is reported. The synthetic pathway involves one pot, synthesis of bis-aldehydes, malononitrile, and pyrazolone in the presence of pyridine. The anticancer activity of the synthesized products against MCF7, HEPG2, and A549 cell lines was assessed. Docking studies were performed and indicated the best binding mode compared to the standard ligand sorafenib.

Cloning and expression of the recombinant NP24I protein from tomato fruit and study of its antimicrobial activity

Thaumatin-like proteins (TLPs) constitutes a homogeneous family, members of which are produced by plants in response to different kinds of stress. NP24 protein is one of such salt-induced protein from tomato ( Solanum lycopersicum ) and it belongs to TLPs family. NP24 is a 24 kDa (207 amino acid) antimicrobial TLP found in tomato fruits. One isoform (NP24I) of NP24 was discovered in the outer pericarp of tomato fruit and is reported to play a possible role in ripening of the fruit in addition to its antimicrobial activity. In this study, the total RNA was isolated successfully from the outer pericarp of ripe (red) tomato fruit. cDNA was prepared and the gene coding for NP24I protein was amplified using conventional polymerase chain reaction (PCR). The gene was then cloned into Mach1™- T1 ® Escherichia coli cells, then subcloned into the over-expression vector pET-28a (+) using BL21 expression bacteria. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that the gene was over-expressed in E. coli as inclusion bodies. Optimization of the recombinant NP24I protein solubility was achieved by cold induction through decreasing both expression temperature and Isopropyl-beta-thio galactopyranoside (IPTG) concentration. The recombinant NP24I protein was purified using Ni-NTA resin, and then the antimicrobial activity of the purified recombinant NP24I protein was tested. The aims of this work were to study the cloning and expression of NP24 protein from local tomato cultivar in a prokaryotic system and to test the activity of the recombinant NP24, as well as to prove the activity of native protein on the bacterial as well as fungal growth. Key words: Pathogenesis-related proteins (PR), low molecular weight thaumatin-like protein (TLPs), cloning, Escherichia coli, cold induction, antimicrobial activity, tomato (Solanum lycopersicum).

DNA Fragmentation, Cell Cycle Arrest, and Docking Study of Novel Bis Spiro-cyclic 2-oxindole of Pyrimido[4,5-b]quinoline-4,6-dione Derivatives Against Breast Carcinoma

BACKGROUND Recently, it is reported that heterocycles containing pyrimidoquinoline moiety show a broad spectrum of medicinal and pharmacological properties including anticancer, anti-microbial, anti-inflammatory activities, analgesic and antiviral. In additions, spirocyclicoxindole containing compounds represent an important class of compounds that exhibit wide range of biological properties. The asymmetric chiral spiro carbon is considered to be the main criteria of the bioactivities. Spirooxindole structures represent the main skeleton for various alkaloids and pharmaceutically important compounds. Among them, the naturally occurring pyrrolidinylespirooxindole alkaloid, horsifiline that exhibits anticancer activity against human brain cancer cell lines. OBJECTIVE The objective of this study is the synthesis of novel bis spiro-cyclic 2-oxindole of pyrimido[4,5-b]quinoline derivatives and evaluate the anticancer activity of new compounds for synergistic purpose. Different genetic tools were used in an attempt to know the mechanism of action of this compound against breast cancer. METHOD An efficient one pot synthesis of bis spiro-cyclic 2-oxindole derivatives of pyrimido[4,5- b]quinoline-4,6-dione using 6-aminouracil, bis-isatin and dimedone has been developed. The cytotoxic effect against different human cell lines MCF7, HCT116 and A549 cell lines was evaluated. The derivative 6a, was found the most encouraging compound in this series and it was selected for molecular studies against MCF7. RESULTS Our data indicated that compound 6a is an attractive target for breast cancer, as it inhibits proliferation, cell cycle progression and induces apoptosis of tumor cells. This inhibition is mediated by fragmentation of genomic DNA, up-regulation of [caspase-3, tumor suppressor gene p53, and pro-apoptotic gene BAX], and down-regulation of anti-apoptotic BCL2 gene. In additions it caused cell cycle arrest in S phase. This work provides an evidence of the potent effect of the new compound 6a and assists in the progress of new healing agents for cancer. CONCLUSION We have developed an efficient method for the synthesis of novel bioactive bis spirocyclic 2-oxindole derivatives incorporating pyrimido[4,5-b]quinoline derivatives. Most of our new derivatives give potent cytotoxic effect more than the standard drug Fluorouracil (5-FU) especially, compound 6a which was the most active and promising one in this series against MCF7, HCT116, and A549 cell lines.

Synthesis, cytotoxicity, antimicrobial and docking simulation of novel pyrazolo[3,4-d]pyrimidine and pyrazolo[4,3-e][1,2,4]triazolo[3,4-c]pyrimidine derivatives

BACKGROUND Isobutyrohydrazonoyl bromide 1 was used as a precursor for the synthesis of 4-imino-3-isopropyl-1-(4-nitrophenyl)-1,4-dihydro-5H-pyrazolo[3,4-d]pyrimidin-5-amine 4, which was converted into hydrazino derivative 5 by heating with hydrazine hydrate at reflux. Hydrazino, as well as imino-amino derivatives, underwent condensation and cyclization reactions to give pyrazolo[ 3,4-d]pyrimidine and pyrazolo[4,3-e][1,2,4]triazolo[3,4-c]pyrimidine derivatives, respectively. METHOD Antimicrobial studies are performed using two-gram positive bacteria and two-gram negative bacteria. RESULTS Data revealed that compound 9a is the most promising antibacterial agent with high efficiency (low MIC value (48 μg/ml)). The cytotoxic assay was investigated for in vitro antitumor screening against Caucasian breast adenocarcinoma MCF7, hepatocellular carcinoma HepG2 and colon carcinoma HCT-116 cell lines. CONCLUSION The results are compared with doxorubicin standard anticancer drugs as well as normal cell lines like MCF10 and MCF12. Molecular docking was carried out for the highest potent compound 8c with the binding site of dihydrofolate reductase enzyme DHFR PDB:ID (1DLS).

Molecular Studies on Novel Antitumor Bis 1,4-Dihydropyridine Derivatives Against Lung Carcinoma and Their Limited Side Effects On Normal Melanocytes

BACKGROUND Cancer is a complex genetic disease which is characterized by an abnormal cell growth, invasion and spreading to other parts of the body. There are several factors that lead to cancer by causing DNA damage and the impairment of its repair. Treatment of cancer using the chemotherapeutic drugs have adverse side effects such as toxicity as they lose their specificity toward cancer cells and affect also normal cells. Moreover, the cancer cells can resist the chemotherapeutic agents and make them ineffective. For these reasons, much attentions have been paid to develop new drugs with limited side effects on normal cells and to diminish cancer resistance to drug chemotherapy. Recently, some 1,4-dihydropyridine derivatives were reported to act as Multi-Drug Resistance (MDR) modulators that inhibit p-glycoprotein which is responsible for the inability of drugs to enter the cancer cells. Also 1,4-DHPs have antimutagenic properties against chemicals via modulating DNA repair when studied on drosophila. OBJECTIVE The objective of this study is the synthesis of bis 1,4-DHPs incorporating ester as well as ether linkages and evaluate the anticancer activity of new compounds for synergistic purpose. Different genetic tools were used in an attempt to know the mechanism of action of this compound against lung cancer. METHOD An efficient one pot synthesis of bis 1,4-DHPs using 3-aminocrotononitrile and bis(aldehydes) has been developed. The cytotoxic effect against human cell lines MCF7, and A549 cell lines was evaluated. RESULTS All compounds exhibited better cytotoxicity toward lung carcinoma cells than breast cancer cells. With respect to lung carcinoma cell line (A549), compound 10 was the most active compound and the three other compounds 7, 8, and 9 showed comparable IC50 values. In case of breast cancer cell line (MCF7), the most active one was compound 7, while compound 8 recorded the least activity. CONCLUSION we have developed an efficient method for the synthesis of novel bis 1,4-dihydropyridine derivatives incorporating ester or ether linkage. All compounds showed better cytotoxicity results against A549 than MCF7, so that lung carcinoma cell line was chosen to perform the molecular studies on it. The results showed that all compounds (7, 8, 9 and 10) caused cell cycle arrest at G1 phase. The molecular docking study on CDK2 confirmed the results of cell cycle assay which showed good binding energy between the compounds and the active site of enzyme indicating the inhibition of the enzyme.

Apoptotic induction mediated p53 mechanism and Caspase-3 activity by novel promising cyanoacrylamide derivatives in breast carcinoma

New cyanoacrylamide derivatives were theoretically examined for their binding abilities to a protein model of apoptosis inhibitor proteins x-IAP and c-IAP1 using molecular modeling. The two compounds 5a and 5b proved promising IAP antagonists, where they have good binding affinity toward the selected active domains. Anticancer activity of all derivatives was performed on different human cancer cell lines (HCT116, Caco2, and MCF7) as well as normal line (HBF4). Data revealed that breast carcinoma was more sensitive to the novel compounds than other lines especially compounds 5a and 5b, but all derivatives lost their cytotoxic effect in case of Caco2 cell line and they showed low cytotoxic effect toward HCT116 cells except compound 3. The flow cytometric analysis revealed that the two compounds 5a and 5b induced apoptosis to 46.5% and 54.8% respectively, relative to control 8.06%. In addition, PCR results indicated that the two compounds 5a and 5b induced the expression of p53 gene and decreased induction of BCL2 (anti-apoptotic gene), while the two compounds have no effect on the protein expression of Caspase-9. By monitoring the presence of Caspase-3 which was a mean to detect apoptotic death in breast carcinoma, the two compounds have stimulated the induction of apoptosis by increasing the production of Caspase-3 protein. Finally, it was concluded that the two compounds 5b and 5a have the most promising anti-cancer activity against human breast carcinoma (MCF7), and it is believed that the anticancer activities of these two compounds were due to being the most effective in the inhibition of a member of IAPs groups, leading to activation of p53 gene and the Caspase-3 dependent apoptosis.