Some Benzoxazole Derivatives as Potential mTOR Inhibitors: Anticancer Activity and Molecular Docking Studies in Breast Cancer

Year 2025, Volume: 51 Issue: 3, 443 - 450, 08.12.2025

Çağla Zübeyde Köprü , Burcu Baba , Shoruq Ahmed Naji , İlkay Yıldız , Ayşegül Akbay

https://doi.org/10.32708/uutfd.1728900

https://izlik.org/JA48ZY62CU

Abstract

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited treatment options, highlighting the need for novel targeted therapies. The mechanistic target of rapamycin (mTOR) is a key regulator of cancer cell proliferation and survival, making it an attractive target for drug development. Based on this, we investigated the anticancer effects of four previously synthesized benzoxazole derivatives—2-(4-isopropylphenyl)-5-nitrobenzoxazole (i), 2-(2,3-dimethylphenyl)-6-nitrobenzoxazole (ii), 2-(2,4-dimethylphenyl)-5-nitrobenzoxazole (iii), and 2-(2,4-dimethylphenyl)-6-nitrobenzoxazole (iv)—through in vitro cytotoxicity assays and molecular docking studies. The cytotoxic effects of the compounds were evaluated using the MTT assay on MDA-MB-231 cells, which were treated with different concentrations (0–100 μM) for 48 hours. To further explore the mechanism of action, molecular docking was performed using mTOR as the target. There was a dose-dependent reduction in cell viability, with compound ii exhibiting the highest cytotoxic activity (IC50= 40.99±0.06 μM). According to molecular docking, all compounds demonstrated strong binding interactions with key residues such as Trp2239, Lys2187, Asp23357, and Val2240, as well as coordination with magnesium ions, supporting their role as mTOR inhibitors. Our results revealed that these benzoxazoles could function as potential candidates for exerting their anticarcinogenic effects on MDA-MB-231 cells through mTOR inhibition.

Keywords

breast cancer , mTOR inhibitors , benzoxazole , molecular docking , anticancer activity

Ethical Statement

Not applicable.

Supporting Institution

The authors did not receive support from any organization for this work.

Thanks

Breast cancer cell line was a kind gift from Prof. Dr. Betül Çelebi Saltık.

Bazı Benzoksazol Türevlerinin Potansiyel mTOR İnhibitör Olarak İncelenmesi: Meme Kanserinde Antikanser Aktivite ve Moleküler Yerleştirme Çalışmaları

https://izlik.org/JA48ZY62CU

Abstract

Üçlü negatif meme kanseri (TNBC), yeni hedefe yönelik tedavilere duyulan ihtiyacı vurgulayan, sınırlı tedavi seçeneklerine sahip agresif bir meme kanseri alt tipidir. Rapamisinin (mTOR) mekanik hedefi, kanser hücresi proliferasyonu ve canlılığının kilit bir düzenleyicisidir ve bu da onu ilaç geliştirme için ilgi çekici bir hedef haline getirmektedir. Bu nedenle, in vitro sitotoksisite deneyleri ve moleküler yerleştirme (docking) çalışmaları yoluyla daha önce sentezlenmiş dört benzoksazol türevinin —2- (4-izopropilfenil) -5-nitrobenzoksazol (i), 2- (2,3-dimetilfenil) -6-nitrobenzoksazol (ii), 2- (2,4-dimetilfenil) -5-nitrobenzoksazol (iii), ve 2- (2,4-dimetilfenil) —6-nitrobenzoksazol (iv) - antikanser potansiyeli araştırılmıştır. Bileşiklerin MDA-MB-231 hücreleri üzerindeki sitotoksik etkileri, 48 saat boyunca farklı konsantrasyonlarla (0-100 μM) muamele edilerek MTT deneyi ile değerlendirilmiştir. Etki mekanizmasını daha ayrıntılı araştırmak amacıyla, hedef protein olarak mTOR seçilerek moleküler docking çalışmaları gerçekleştirilmiştir. Hücre canlılığında doza bağlı bir azalma gözlemlenmiş ve bileşik ii en yüksek sitotoksik aktiviteyi göstermiştir (IC50 = 40,99 ± 0,06 μM). Moleküler docking çalışmaları sonucunda, tüm bileşiklerin mTOR proteininin Trp2239, Lys2187 ve Val2240 gibi anahtar kalıntıları ile güçlü bağlanma etkileşimleri gösterdiği ve ayrıca magnezyum iyonları ile koordinasyon sağladığı belirlenmiştir. Bu bulgular, bileşiklerin mTOR inhibitörleri olarak potansiyel rollerini desteklemektedir. Sonuçlarımız, bu benzoksazol türevlerinin, mTOR inhibisyonu yoluyla MDA-MB-231 hücreleri üzerinde antikarsinojenik etkilerini gösterebilecek potansiyel adaylar olabileceğini ortaya koymuştur.

Keywords

meme kanseri , mTOR inhibitörleri , benzoksazol , moleküler yerleştirme , antikanser aktivite

References

• 1. Liu X, Liu J, Yan B et al. Study of the PI3K/Akt/mTOR signaling pathway in vitro and molecular docking analysis of periplocin inhibits cell cycle progression and induces apoptosis in MDA-MB-231. Environ Toxicol. 2024;39(1):444-456. doi: 10.1002/tox.23981.
• 2. Omar AME, AboulWafa OM, Amr ME, El-Shoukrofy MS. Antiproliferative activity, enzymatic inhibition and apoptosis-promoting effects of benzoxazole-based hybrids on human breast cancer cells. Bioorg Chem. 2021;109:104752. doi: 10.1016/j.bioorg.2021.104752.
• 3. Zhu S, Wu Y, Song B et al. Recent advances in targeted strategies for triple-negative breast cancer. J Hematol Oncol. 2023;16(1):100. doi: 10.1186/s13045-023-01497-3.
• 4. Kattan SW, Nafie MS, Elmgeed GA et al. Molecular docking, anti-proliferative activity and induction of apoptosis in human liver cancer cells treated with androstane derivatives: Implication of PI3K/AKT/mTOR pathway. J Steroid Biochem Mol Biol. 2020;198:105604. doi: 10.1016/j.jsbmb.2020.105604.
• 5. Zhang HP, Jiang RY, Zhu JY et al. PI3K/AKT/mTOR signaling pathway: an important driver and therapeutic target in triple-negative breast cancer. Breast Cancer. 2024; 31(4):539-551. doi: 10.1007/s12282-024-01567-5.
• 6. Das A, Matada GSPM, Dhiwar P et al. Molecular recognition of some novel mTOR kinase inhibitors to develop anticancer leads by drug-likeness, molecular docking and molecular dynamics based virtual screening strategy. Computational Toxicology. 2023; 25, 100257.
• 7. Zou Z, Tao T, Li H, Zhu X. mTOR signaling pathway and mTOR inhibitors in cancer: progress and challenges. Cell Biosci. 2020;10:31. doi: 10.1186/s13578-020-00396-1.
• 8. Pandey S, Mondal S, Kajal K et al. Current progress in the targeted therapy of breast cancer: Structure-activity correlation and docking studies (2015-2021). Arch Pharm (Weinheim). 2023;356(8):e2200602. doi: 10.1002/ardp.202200602.
• 9. Omar AME, AboulWafa OM, El-Shoukrofy MS, Amr ME. Benzoxazole derivatives as new generation of anti-breast cancer agents. Bioorg Chem. 2020;96:103593. doi: 10.1016/j.bioorg.2020.103593.
• 10. AboulWafa OM, Daabees HMG, El-Said AH. Benzoxazole-appended piperidine derivatives as novel anticancer candidates against breast cancer. Bioorg Chem. 2023;134:106437. doi: 10.1016/j.bioorg.2023.106437.
• 11. Kuzu B, Hepokur C, Turkmenoglu B, Burmaoglu S, Algul O. Design, synthesis and in vitro antiproliferation activity of some 2-aryl and -heteroaryl benzoxazole derivatives. Future Med Chem. 2022;14(14):1027-1048. doi: 10.4155/fmc-2022-0076.
• 12. Zhong W, Tang X, Liu Y et al. Benzoxazole Derivative K313 Induces Cell Cycle Arrest, Apoptosis and Autophagy Blockage and Suppresses mTOR/p70S6K Pathway in Nalm-6 and Daudi Cells. Molecules. 2020;25(4):971. doi: 10.3390/molecules25040971.
• 13. Xiao M, Lin C, Yang Z et al. Compound TDB (Tricyclic decyl benzoxazole) induces autophagy-dependent apoptosis in the gastric cancer cell line MGC-803 by regulating PI3K/AKT/mTOR. Am J Transl Res. 2021;13(1):73-87.
• 14. Noolvi MN, Patel HM, Kaur M. Benzothiazoles: search for anticancer agents. Eur J Med Chem. 2012;54:447-62. doi: 10.1016/j.ejmech.2012.05.028.
• 15. Shi DF, Bradshaw TD, Wrigley S et al. Antitumor benzothiazoles. 3. Synthesis of 2-(4-aminophenyl) benzothiazoles and evaluation of their activities against breast cancer cell lines in vitro and in vivo. J Med Chem. 1996;39(17):3375-84. doi: 10.1021/jm9600959.
• 16. Hendriks HR, Govaerts AS, Fichtner I et al. Pharmacologically directed strategies in academic anticancer drug discovery based on the European NCI compounds initiative. Br J Cancer. 2017;117(2):195-202. doi: 10.1038/bjc.2017.167.
• 17. Abdelgawad MA, Belal A, Omar HA, Hegazy L, Rateb ME. Synthesis, anti-breast cancer activity, and molecular modeling of some benzothiazole and benzoxazole derivatives. Arch Pharm (Weinheim). 2013;346(7):534-41. doi: 10.1002/ardp.201300044.
• 18. Karatas E, Foto E, Ertan-Bolelli T et al. Discovery of 5-(or 6)-benzoxazoles and oxazolo[4,5-b] pyridines as novel candidate antitumor agents targeting hTopo IIα. Bioorg Chem. 2021;112:104913. doi: 10.1016/j.bioorg.2021.104913.
• 19. Protein Data Bank information page. https://www.rcsb.org/structure/4JSV
• 20. Schrödinger Release 2022-4: Glide, Schrödinger, LLC, New York, NY, 2022. https://www.schrodinger.com/.
• 21. Wizard, P. P. (2017). Schrödinger Suite 2011 Protein Preparation Wizard. Epik version, 2.
• 22. Velázquez-Libera JL, Durán-Verdugo F, Valdés-Jiménez A, Núñez-Vivanco G, Caballero J. LigRMSD: a web server for automatic structure matching and RMSD calculations among identical and similar compounds in protein-ligand docking. Bioinformatics. 2020; 1;36(9):2912-2914. doi: 10.1093/bioinformatics/btaa018.
• 23. Carey L, Winer E, Viale G, Cameron D, Gianni L. Triple-negative breast cancer: disease entity or title of convenience? Nat Rev Clin Oncol. 2010;7(12):683-92. doi: 10.1038/nrclinonc.2010.154.
• 24. Jiang YZ, Ma D, Suo C et al. Genomic and Transcriptomic Landscape of Triple-Negative Breast Cancers: Subtypes and Treatment Strategies. Cancer Cell. 2019;35(3):428-440.e5. doi: 10.1016/j.ccell.2019.02.001.
• 25. Yunokawa M, Koizumi F, Kitamura Y et al. Efficacy of everolimus, a novel mTOR inhibitor, against basal-like triple-negative breast cancer cells. Cancer Sci. 2012;103(9):1665-71. doi: 10.1111/j.1349-7006.2012.02359.x.
• 26. Patidar K, Panwar U, Vuree S et al. An In silico Approach to Identify High Affinity Small Molecule Targeting m-TOR Inhibitors for the Clinical Treatment of Breast Cancer. Asian Pac J Cancer Prev. 2019;20(4):1229-1241. doi: 10.31557/APJCP.2019.20.4.1229.
• 27. Yoon MS. Nanotechnology-Based Targeting of mTOR Signaling in Cancer. Int J Nanomedicine. 2020;15:5767-5781. doi: 10.2147/IJN.S254574.
• 28. Chen JS, Wang Q, Fu XH et al. Involvement of PI3K/PTEN/AKT/mTOR pathway in invasion and metastasis in hepatocellular carcinoma: Association with MMP-9. Hepatol Res. 2009;39(2):177-86. doi: 10.1111/j.1872-034X.2008.00449.x.
• 29. Chen S, Fisher RC, Signs S et al. Inhibition of PI3K/Akt/mTOR signaling in PI3KR2-overexpressing colon cancer stem cells reduces tumor growth due to apoptosis. Oncotarget. 2016;8(31):50476-50488. doi: 10.18632/oncotarget.9919.
• 30. Liu F, Gao S, Yang Y et al. Antitumor activity of curcumin by modulation of apoptosis and autophagy in human lung cancer A549 cells through inhibiting PI3K/Akt/mTOR pathway. Oncol Rep. 2018;39(3):1523-1531. doi: 10.3892/or.2018.6188.
• 31. Hassan Z, Schneeweis C, Wirth M et al. mTOR inhibitor-based combination therapies for pancreatic cancer. Br J Cancer. 2018;118(3):366-377. doi: 10.1038/bjc.2017.421.
• 32. Montero JC, Esparís-Ogando A, Re-Louhau MF et al. Active kinase profiling, genetic and pharmacological data define mTOR as an important common target in triple-negative breast cancer. Oncogene. 2014;33(2):148-56. doi: 10.1038/onc.2012.572.
• 33. Gordon V, Banerji S. Molecular pathways: PI3K pathway targets in triple-negative breast cancers. Clin Cancer Res. 2013;19(14):3738-44. doi: 10.1158/1078-0432.CCR-12-0274.
• 34. Kalimutho M, Parsons K, Mittal D et al. Targeted Therapies for Triple-Negative Breast Cancer: Combating a Stubborn Disease. Trends Pharmacol Sci. 2015;36(12):822-846. doi: 10.1016/j.tips.2015.08.009.
• 35. Chresta CM, Davies BR, Hickson I et al. AZD8055 is a potent, selective, and orally bioavailable ATP-competitive mammalian target of rapamycin kinase inhibitor with in vitro and in vivo antitumor activity. Cancer Res. 2010;70(1):288-98. doi: 10.1158/0008-5472.CAN-09-1751.
• 36. Irfan A, Batool F, Zahra Naqvi SA et al. Benzothiazole derivatives as anticancer agents. J Enzyme Inhib Med Chem. 2020;35(1):265-279. doi: 10.1080/14756366.2019.1698036.
• 37. Abdelgawad MA, Belal A, Omar HA, Hegazy L, Rateb ME. Synthesis, anti-breast cancer activity, and molecular modeling of some benzothiazole and benzoxazole derivatives. Arch Pharm (Weinheim). 2013;346(7):534-41. doi: 10.1002/ardp.201300044.
• 38. El-Ghobashy NM, El-Sayed SM, Shehata IA, El-Ashmawy MB. Synthesis, biological evaluation, and molecular modeling studies of new benzoxazole derivatives as PARP-2 inhibitors targeting breast cancer. Sci Rep. 2022;12(1):16246. doi: 10.1038/s41598-022-20260-1.
• 39. Liu X, Liu J, Yan B, et al. Study of the PI3K/Akt/mTOR signaling pathway in vitro and molecular docking analysis of periplocin inhibits cell cycle progression and induces apoptosis in MDA-MB-231. Environ Toxicol. 2024;39(1):444-456. doi: 10.1002/tox.23981.
• 40. Wu HT, Li CL, Fang ZX, et al. Induced Cell Cycle Arrest in Triple-Negative Breast Cancer by Combined Treatment of Itraconazole and Rapamycin. Front Pharmacol. 2022; 19;13:873131. doi: 10.3389/fphar.2022.873131.
• 41. Yao D, Jiang J, Zhang H, et al. Design, synthesis and biological evaluation of dual mTOR/HDAC6 inhibitors in MDA-MB-231 cells. Bioorg Med Chem Lett. 2021;47:128204. doi: 10.1016/j.bmcl.2021.128204.
• 42. Tran THM, Dhandapani S, Abdus S, Kim YJ. 1-Dehydro-6-Gingerdione Exerts Anticancer Effects on MDA-MB-231 Cells and in the Xenograft Mouse Model by Promoting the Ferroptosis Pathway. Phytother Res. 2024;38(12):5901-5917. doi: 10.1002/ptr.8331.