Tangeretin suppresses HER2-driven breast cancer via PI3K/AKT/mTOR inhibition and caspase-dependent apoptosis
DOI:
https://doi.org/10.3329/bjp.v21i1.85717Keywords:
Anti-cancer, Apoptosis, Breast cancer, PI3K/AKT/mTOR signaling, Tangeretin, CaspaseAbstract
Tangeretin, a citrus-derived polymethoxylated flavone, exhibits potent and selective anti-cancer activity against HER2-positive breast cancer. It demonstrated cytotoxicity in SKBR3 cells (IC₅₀ = 19.5 ± 1.7 µM) and MCF-7 cells (IC₅₀ = 36.2 ± 2.4 µM), while sparing non-tumorigenic MCF-10A cells (>90% viability; IC₅₀ = 327.5 ± 18.2 µM). Tangeretin markedly reduced clonogenic survival (51.4 ± 3.1 colonies in SKBR3; 78.1 ± 3.7 in MCF-7) and induced pronounced apoptosis, as evidenced by late apoptotic staining (50.6 ± 2.3%), DNA laddering, and strong activation of caspase-3/7 (3.4 ± 0.1-fold) and caspase-9 (2.9 ± 0.1-fold). Flow cytometry revealed significant G₂/M phase arrest in SKBR3 cells (38.9 ± 2.0%). Mechanistically, tangeretin suppressed AKT kinase activity (0.4 ± 0.04-fold), comparable to MK-2206 (0.3 ± 0.0-fold), and reduced the expression of phosphorylated HER2 (p-HER2), p-PI3K, p-AKT, p-mTOR, p-p70S6K, and cyclin D1. These findings establish tangeretin as a selective HER2-targeted anti-cancer candidate that acts through dual inhibition of the PI3K/AKT/mTOR pathway and induction of mitochondrial apoptosis.
Downloads
7
2
References
Braga CP, Ferreira AK, Ribeiro DL, Da Silva PH, Chaves DS, São Pedro GM, Antunes LM. Tangeretin enhances doxorubicin-mediated cytotoxicity by modulating apoptosis. Phytomedicine 2021; 81: 153422.
Brix N, Samaga D, Hennel R, Gehr K, Rödel F, Zips D, Brüchner K. Establishment of clonogenic survival assays for radiobiological analysis of cancer cell lines in vitro. Radiat Oncol. 2020; 15: 37.
Chen J, Xu B, Sun J. Polymethoxylated flavones as modulators of oncogenic signaling in human cancers. Biomed Pharmacother. 2019; 112: 108682.
Chen J, Xu J, Yu H. Anticancer activities of polymethoxylated flavones from citrus. J Funct Foods. 2020; 64: 103708.
Crowley LC, Christensen ME, Waterhouse NJ. Measuring cell death by microscopy and flow cytometry. Methods Mol Biol. 2016; 1419: 65-75.
Fang CY, Lin YW, Wu CL, Hou WC, Chou YC, Chen YK. Tangeretin suppresses PI3K/AKT signaling and inhibits tumor growth. Cancer Lett. 2016; 370: 265-73.
Guo S, Sun Y, Wang Y. Pharmacological properties of tangeretin. Food Funct. 2014; 5: 2392-400.
Huang CY, Chiang SF, Lin TY. Targeting PI3K/AKT signaling in breast cancer: Molecular mechanisms and therapeutic perspectives. Cancer Lett. 2018; 420: 1-9.
Lai CS, Ho CT, Pan MH. Polymethoxylated flavones activate apoptotic pathways and inhibit carcinogenesis. Mol Nutr Food Res. 2011; 55: 32-45.
Lai CS, Wu JC, Pan MH. Tangeretin inhibits breast cancer cell proliferation and enhances paclitaxel sensitivity. Cancer Lett. 2007; 251: 158-70.
Lee MH, Kim JH. Flavonoid-induced modulation of PI3K/AKT/mTOR pathway in breast cancer cells. Mol Carcinog. 2020; 59: 324–39.
Li Y, Ding X, Li Y, He S. Tangeretin: Chemistry, pharmacological properties, and potential applications. Front Pharmacol. 2022; 13: 864112.
Liu K, Liu P. Dual AO/EB staining to detect apoptosis in osteosarcoma cells. Med Sci Monit Basic Res. 2015; 21: 15-24.
Loibl S, Gianni L. HER2-positive breast cancer. Lancet 2017; 389: 2415-29.
Loibl S, Majewski I, Guarneri V, Nekljudova V, Holmes E, Bria E, Denkert C, Schneeweiss A, Schem C, Sotiriou C, Andre F, Conte P, Fasching PA, Hurvitz S, Carey LA, Colleoni M, Krop I, Baselga J. PIK3CA mutations and survival in operable breast cancer. J Clin Oncol. 2016; 34: 123-31.
Maadi H, Kazemi T, Ghasemi A, Asgarian-Omran H, Shabani M, Sharifian R, Mehrzad J. IP-kinase assay: A non-radioactive method to assess kinase activity. Bioprotocol 2014; 4: e1059.
Mayer IA, Arteaga CL. The PI3K/AKT pathway as a target for cancer treatment. Clin Cancer Res. 2016; 22: 2550-57.
Miller TW, Rexer BN, Garrett JT, Arteaga CL. Mutations in the phosphatidylinositol 3-kinase pathway: Role in tumor progression and therapeutic resistance. Cancer Res. 2011; 71: 560-65.
Miyata Y, Matsuo T, Sagara Y, Fujii T, Okada K, Ohba K, Sakai H. Antitumor properties of polymethoxylated flavones. Biofactors 2018; 44: 303-12.
Moja L, Tagliabue L, Balduzzi S, Parmelli E, Pistotti V, Guarneri V, D Amico R. Trastuzumab-containing regimens for early breast cancer. Cochrane Database Syst Rev. 2012; CD006243.
Niles AL, Moravec RA, Riss TL. Caspase-Glo® assays for apoptosis research. Assay Guidance Manual. Bethesda (MD): Eli Lilly & NCBI, 2016; pp 1-24.
Panche AN, Diwan AD, Chandra SR. Flavonoids: An over-view. J Nutr Sci. 2016; 5: e47.
Park JY, Kim EN, Kim JS. Flavonoid-mediated checkpoint activation leads to G2/M arrest in breast cancer cells. Oncol Rep. 2016; 35: 876-84.
Pozarowski P, Darzynkiewicz Z. Analysis of cell cycle by flow cytometry. Methods Mol Biol. 2004; 281: 301-12.
Rimawi MF, Schiff R, Osborne CK. Targeting HER2 for the treatment of breast cancer. Annu Rev Med. 2015; 66: 111-28.
Riss TL, Moravec RA, Niles AL, Benink HA, Worzella TJ, Minor L. Cell viability assays. Assay Guidance Manual. Bethesda (MD): Eli Lilly & NCBI, 2016.
Schneider CA, Rasband WS, Eliceiri KW. NIH Image to ImageJ: 25 years of image analysis. Nat Methods. 2012; 9: 671-75.
Singh A, Sharma R, Mehra R. HER2-driven signaling and resistance in breast cancer: Therapeutic implications. Front Oncol. 2021; 11: 651233.
Slamon DJ, Leyland-Jones B, Shak S, Fuchs H, Paton V, Bajamonde A, Fleming T, Eiermann W, Wolter J, Pegram M, Baselga J, Norton L. Use of chemotherapy plus a monoclonal antibody against HER2 for metastatic breast cancer that overexpresses HER2. N Engl J Med. 2001; 344: 783-92.
Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, Bray F. Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2021; 71: 209-49.
Vu T, Claret FX. Trastuzumab resistance: Mechanisms and clinical implications. Breast Cancer Res. 2012; 14: 203.
Wang X, Zhang H, Chen L. Differential responsiveness of ER-positive breast cancer cells to natural flavonoids. J Cell Biochem. 2017; 118: 3834-45.
Zhang L, Xu J, Zhang Y, Wang Y. Tangeretin reverses multi-drug resistance in breast cancer cells. J Cell Biochem. 2020; 121: 1557-69.
Zhao Y, Chen X, Li L. DNA fragmentation patterns during apoptosis: Evidence and techniques. Cell Death Dis. 2019; 10: 750.
Zhao Y, Chen X, Li L. Flavonoid-induced mitochondrial dysfunction in cancer apoptosis. Cell Death Dis. 2020; 11: 193.
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Jaggareddygari Shruthi Reddy, Puligilla Shankaraiah
This work is licensed under a Creative Commons Attribution 4.0 International License.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
