Publications by authors named "Yasmin M Attia"

9 Publications

  • Page 1 of 1

Conversion of RNA Aptamer into Modified DNA Aptamers Provides for Prolonged Stability and Enhanced Antitumor Activity.

J Am Chem Soc 2021 May 14;143(20):7655-7670. Epub 2021 May 14.

Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States.

Aptamers, synthetic single-strand oligonucleotides that are similar in function to antibodies, are promising as therapeutics because of their minimal side effects. However, the stability and bioavailability of the aptamers pose a challenge. We developed aptamers converted from RNA aptamer to modified DNA aptamers that target phospho-AXL with improved stability and bioavailability. On the basis of the comparative analysis of a library of 17 converted modified DNA aptamers, we selected aptamer candidates, GLB-G25 and GLB-A04, that exhibited the highest bioavailability, stability, and robust antitumor effect in experiments. Backbone modifications such as thiophosphate or dithiophosphate and a covalent modification of the 5'-end of the aptamer with polyethylene glycol optimized the pharmacokinetic properties, improved the stability of the aptamers by reducing nuclease hydrolysis and renal clearance, and achieved high and sustained inhibition of AXL at a very low dose. Treatment with these modified aptamers in ovarian cancer orthotopic mouse models significantly reduced tumor growth and the number of metastases. This effective silencing of the phospho-AXL target thus demonstrated that aptamer specificity and bioavailability can be improved by the chemical modification of existing aptamers for phospho-AXL. These results lay the foundation for the translation of these aptamer candidates and companion biomarkers to the clinic.
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http://dx.doi.org/10.1021/jacs.9b10460DOI Listing
May 2021

Blockade of CDK7 Reverses Endocrine Therapy Resistance in Breast Cancer.

Int J Mol Sci 2020 Apr 23;21(8). Epub 2020 Apr 23.

Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.

Cyclin-dependent kinase (CDK)-7 inhibitors are emerging as promising drugs for the treatment of different types of cancer that show chemotherapy resistance. Evaluation of the effects of CDK7 inhibitor, THZ1, alone and combined with tamoxifen is of paramount importance. Thus, in the current work, we assessed the effects of THZ1 and/or tamoxifen in two estrogen receptor-positive (ER+) breast cancer cell lines (MCF7) and its tamoxifen resistant counterpart (LCC2) in vitro and in xenograft mouse models of breast cancer. Furthermore, we evaluated the expression of CDK7 in clinical samples from breast cancer patients. Cell viability, apoptosis, and genes involved in cell cycle regulation and tamoxifen resistance were determined. Tumor volume and weight, proliferation marker (Ki67), angiogenic marker (CD31), and apoptotic markers were assayed. Bioinformatic data indicated CDK7 expression was associated with negative prognosis, enhanced pro-oncogenic pathways, and decreased response to tamoxifen. Treatment with THZ1 enhanced tamoxifen-induced cytotoxicity, while it inhibited genes involved in tumor progression in MCF-7 and LCC2 cells. In vivo, THZ1 boosted the effect of tamoxifen on tumor weight and tumor volume, reduced Ki67 and CD31 expression, and increased apoptotic cell death. Our findings identify CDK7 as a possible therapeutic target for breast cancer whether it is sensitive or resistant to tamoxifen therapy.
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http://dx.doi.org/10.3390/ijms21082974DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7215326PMC
April 2020

Part III: Novel checkpoint kinase 2 (Chk2) inhibitors; design, synthesis and biological evaluation of pyrimidine-benzimidazole conjugates.

Eur J Med Chem 2018 Feb 2;146:687-708. Epub 2018 Feb 2.

Department of Chemistry of Natural and Microbial Products, Division of Pharmaceutical and Drug Industries, National Research Centre, Cairo, 12622, Egypt.

Recently a dramatic development of the cancer drug discovery has been shown in the field of targeted cancer therapy. Checkpoint kinase 2 (Chk2) inhibitors offer a promising approach to enhance the effectiveness of cancer chemotherapy. Accordingly, in this study many pyrimidine-benzimidazole conjugates were designed and twelve feasible derivatives were selected to be synthesized to investigate their activity against Chk2 and subjected to study their antitumor activity alone and in combination with the genotoxic anticancer drugs cisplatin and doxorubicin on breast carcinoma, (ER+) cell line (MCF-7). The results indicated that the studied compounds inhibited Chk2 activity with high potency (IC = 5.56 nM - 46.20 nM). The studied candidates exhibited remarkable antitumor activity against MCF-7 (IG = 6.6  μM - 24.9 μM). Compounds 10a-c, 14 and 15 significantly potentiated the activity of the studied genotoxic drugs, whereas, compounds 9b and 20-23 antagonized their activity. Moreover, the combination of compound 10b with cisplatin revealed the best apoptotic effect as well as combination of compound 10b with doxorubicin led to complete arrest of the cell cycle at S phase where more than 40% of cells are in the S phase with no cells at G2/M. Structure-activity relationship was discussed on the basis of molecular modeling study using Molecular modeling Environment program (MOE).
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http://dx.doi.org/10.1016/j.ejmech.2018.01.072DOI Listing
February 2018

Anticancer potentiality of lignan rich fraction of six Flaxseed cultivars.

Sci Rep 2018 01 11;8(1):544. Epub 2018 Jan 11.

Pharmacognosy Department, Faculty of Pharmacy, Cairo University, Kasr El-Einy Street, Cairo, 11562, Egypt.

The objective of our study is to highlight the therapeutic effect and mechanism of action by which purified Flaxseed hydrolysate (PFH) which is a lignan rich fraction exerts its anticancer activity on a human breast cancer cell line (T47D) and in mice bearing tumor. HPLC analysis of PFH of six flaxseed cultivars had shown that PFH of the cultivar Giza 9 (PFH-G9) contains the highest concentration of SDG (81.64 mg/g). The in vitro cytotoxic potentiality of PFH's of six flaxseed cultivars was screened against a panel of human cancer cell lines. PFH -G9 showed the most significant cytotoxic activity against ER-receptor positive breast cell lines MCF7 and T47D with IC 13.8 and 15.8 µg/ml, respectively. Moreover, PFH-G9 reduced the expression of the metastasis marker, 1-α, metalloproteinases and vascular endothelial growth factor (VEGF), one of the most potent stimulators of angiogenesis, while it increased the caspase-3 dependent apoptosis. Our study also showed that dietary intake of 10% of Giza 9 Flaxseeds (FS), fixed oil (FSO) or Flax meal (FSM) twice daily for 3 weeks in mice-bearing solid Ehrlich ascites carcinoma (EAC) resulted in reducing the tumor volume, the expression of estrogen, insulin growth factor, progesterone, VEGF and MMP-2, but enhanced expression of caspase-3.
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http://dx.doi.org/10.1038/s41598-017-18944-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5764973PMC
January 2018

Part II: New candidates of pyrazole-benzimidazole conjugates as checkpoint kinase 2 (Chk2) inhibitors.

Eur J Med Chem 2018 Jan 8;144:859-873. Epub 2017 Dec 8.

Department of Chemistry of Natural and Microbial Products, Division of Pharmaceutical and Drug Industries, National Research Centre, Cairo, 12622, Egypt.

The development of checkpoint kinase 2 (Chk2) inhibitors for the treatment of cancer has been an ongoing and attractive objective in drug discovery. In this study, twenty-one feasible pyrazole-benzimidazole conjugates were synthesized to study their effect against Chk2 activity using Checkpoint Kinase Assay. The antitumor activity of these compounds was investigated using SRB assay. A potentiation effect of the synthesized Chk2 inhibitors was also investigated using the genotoxic anticancer drugs cisplatin and doxorubicin on breast carcinoma, (ER+) cell line (MCF-7). In vivo Chk2 and antitumor activities of 8d as a single-agent, and in combination with doxorubicin, were evaluated in breast cancer bearing animals induced by N-methylnitrosourea. The effect of 8d alone and in combination with doxorubicin was also studied on cell-cycle phases of MCF-7 cells using flow cytometry analysis. The results revealed their potencies as Chk2 inhibitors with IC ranges from 9.95 to 65.07 nM. Generally the effect of cisplatin or doxorubicin was potentiated by the effect of most of the compounds that were studied. The in vivo results indicated that the combination of 8d and doxorubicin inhibited checkpoint kinase activity more than either doxorubicin or 8d alone. There was a positive correlation between checkpoint kinase inhibition and the improvement observed in histopathological features. Single dose treatment with doxorubicin or 8d produced S phase cell cycle arrest whereas their combination created cell cycle arrest at G2/M from 8% in case of doxorubicin to 51% in combination. Gold molecular modelling studies displayed a high correlation to the biological results.
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http://dx.doi.org/10.1016/j.ejmech.2017.12.023DOI Listing
January 2018

Part I: Design, synthesis and biological evaluation of novel pyrazole-benzimidazole conjugates as checkpoint kinase 2 (Chk2) inhibitors with studying their activities alone and in combination with genotoxic drugs.

Eur J Med Chem 2017 Jul 14;134:392-405. Epub 2017 Apr 14.

Department of Chemistry of Natural and Microbial Products, Division of Pharmaceutical and Drug Industries, National Research Centre, Cairo, 12622, Egypt.

Activated checkpoint kinase 2 (Chk2) is a tumor suppressor as one of the main enzymes that affect the cell cycle. 2-Biarylbenzimidazoles are potent selective class of Chk2 inhibitors; the structure-based design was applied to synthesize a new series of this class with replacing the lateral aryl group by substituted pyrazoles. Ten pyrazole-benzimidazole conjugates from the best fifty candidates according to docking programs have been subjected to chemical synthesis in this study. The activities of the conjugates 5-14 as checkpoint kinase inhibitors and as antitumor alone and in combination with genotoxic drugs were evaluated. The effect of compounds 7 and 12 on cell-cycle phases was analyzed by flow cytometry analysis. Antitumor activity of compounds 7 and 12 as single-agents and in combinations with doxorubicin was assessed in breast cancer bearing animals induced by MNU. The Results indicated that compounds 5-14 inhibited Chk2 activity with high potency (IC 52.8 nM-5.5 nM). The cytotoxicity of both cisplatin and doxorubicin were significantly potentiated by the most of the conjugates against MCF-7 cell lines. Compounds 7 and 12 and their combinations with doxorubicin induced the cell cycle arrest in MCF-7 cells. Moreover, compound 7 exhibited marked higher antitumor activity as a single agent in animals than it's combination with doxorubicin or doxorubicin alone. The combination of compound 12 with doxorubicin was greatly effective on animal than their single-dose treatment. In conclusion, pyrazole-benzimidazole conjugates are highly active Chk2 inhibitors that have anticancer activity and potentiate activity of genotoxic anticancer therapies and deserve further evaluations.
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http://dx.doi.org/10.1016/j.ejmech.2017.03.090DOI Listing
July 2017

Anticancer Activities of New N-hetaryl-2-cyanoacetamide Derivatives Incorporating 4,5,6,7-Tetrahydrobenzo[b]thiophene Moiety.

Anticancer Agents Med Chem 2017 ;17(8):1084-1092

Department of Chemistry, Faculty of Science, Cairo University, 12613 Giza, A. R, Egypt.

Aims: Novel series of N-(4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl) cyanoacetamide derivatives are synthesized.

Method: The structure of these compounds was elucidated using different spectral tools. Compounds were evaluated for their cytotoxic activities against different types of human cancer cell lines including, breast (MCF-7, T47D, MDA MB231); liver (HEPG-2); colon (HCT116); prostate (PC3); and cervix (HELA) cells. In this study, we used compounds 11 and 12 that showed the highest cytotoxicity on PC3 and HEPG2 cells, to explore their effects on apoptosis, metastasis and angiogenesis of cancer cells.

Results: Results revealed that the growth inhibition produced by the two selected compounds was due to cytocidal and not due to cytostatic effect in both cell lines. This cytocidal effect was due to up-regulation of caspases-3, and- 9. In addition, the two compounds inhibited the expression of metalloproteinases-2 and 9 (MMP 2&9). Moreover, HIF-1alpha and VEGF expressions were inhibited by both compounds.

Conclusion: In conclusion, N-(4, 5, 6, 7-tetrahydrobenzo[b]thiophen-2-yl) cyanoacetamide derivatives showed different anticancer potential against different cancer cell lines. Compounds 11 and 12 showed the most active cytotoxicity against PC3 and HepG2 cells. Both compounds have apoptotic, anti- metastatic and anti-angiogenic effects.
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http://dx.doi.org/10.2174/1871520617666170110154110DOI Listing
September 2017

Targeting glycolysis by 3-bromopyruvate improves tamoxifen cytotoxicity of breast cancer cell lines.

BMC Cancer 2015 Nov 3;15:838. Epub 2015 Nov 3.

Pharmacology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Kasr Al Eini Street, Fom El Khalig, Cairo, Egypt, 11796.

Background: Tamoxifen is the standard endocrine therapy for ER+ breast cancer; however, many women still relapse after long-term therapy. 3-Bromopyruvate, a glycolytic inhibitor, has shown high selective anti-tumor activity in vitro, and in vivo. The aim of this study was to evaluate the possible augmentation of the effect of tamoxifen via reprograming cancer cell metabolism using 3-bromopyruvate.

Methods: An in vitro screening of antitumor activity as well as the apoptotic, anti-metastatic, and anti-angiogenic potentials of the combination therapy were carried out using different techniques on breast cancer cell lines MCF7and T47D. In addition the antitumor effect of the combined therapy was done on mice bearing tumor.

Results: Our results showed modulation in apoptosis, angiogenesis and metastatic potential by either drug alone; however, their combination has surpassed that of the individual one. Combination regimen enhanced activated caspases-3, 7 and 9, as well as oxidative stress, signified by increased malondialdehyde and decreased glutathione level. Additionally, the angiogenesis and metastasis markers, including hypoxia inducing factor-1α, vascular endothelia growth factor, and metaloproteinases-2 and 9 were decreased after using the combination regimen. These results were further confirmed by the in vivo study, which depicted a decrease in the tumor volume and angiogenesis and an increase in oxidative stress as well.

Conclusion: 3-bromopyruvate could be a valuable compound when added with tamoxifen in breast cancer treatment.
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http://dx.doi.org/10.1186/s12885-015-1850-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4630933PMC
November 2015

Cytotoxic and antimicrobial evaluations of novel apoptotic and anti-angiogenic spiro cyclic 2-oxindole derivatives of 2-amino-tetrahydroquinolin-5-one.

Arch Pharm (Weinheim) 2015 Feb;348(2):113-24

Department of Chemistry, Faculty of Science, Cairo University, Giza, Egypt.

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.
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http://dx.doi.org/10.1002/ardp.201400304DOI Listing
February 2015
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