ATM Inhibitor KU-60019 Induces Extracellular Vesicle Secretion in HeLa Cells

Aleksander Aleksandrov; Dimitar Iliev; Banko Bankov; Georgi Antov; Svetozar Stoichev

doi:10.26650/EurJBiol.2026.1869737

ATM Inhibitor KU-60019 Induces Extracellular Vesicle Secretion in HeLa Cells

Abstract

Objective: Inhibitors of the ataxia-telangiectasia mutated (ATM) kinase are utilised to enhance the genotoxicity of chemotherapeutic agents. The two widely used ATM inhibitors (ATMi)-KU-55933 and KU-60019 are also recognised as autophagy inhibitors. Suppression of late-stage autophagy can promote the secretion of extracellular vesicles (EVs), and cancer-derived EVs are implicated in disease progression and metastasis. Therefore, this study aimed to elucidate the effects of these ATMi on EV secretion.

Materials and Methods: The effects of ATMi on autophagy were studied using immunoblotting and microscopy in HeLa cells. EVs from treated cells were isolated via differential centrifugation and analyzed by immunoblotting and dynamic light scattering. The cytotoxicity of the treatments was evaluated using flow cytometry.

Results: KU-60019 and KU-55933 caused LC3B-II and p62 accumulation in HeLa cells, as well as the secretion of large and small EVs containing both autophagy (LC3B-II, p62) and EV markers (CD63 and syntenin). The addition of etoposide to treatment with KU-60019 synergistically enhanced EV secretion and further increased LC3B-II accumulation in cell lysates, while reducing p62 accumulation. Nevertheless, compared to treatment with etoposide alone, the combined treatment resulted in higher levels of p62 and reduced γH2AX ubiquitination, which concurs with previous reports on the effects of p62 accumulation on the DDR.

Conclusion: Our results reveal the potency of ATMi as EV inducers and the interplay between ATMi and etoposide in the regulation of EV secretion. The potential impact of ATMi-induced EVs on the tumour microenvironment should be considered in future trials.

Keywords

References

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Details

Primary Language

English

Subjects

Cancer Biology, Animal Cell and Molecular Biology

Journal Section

Research Article

Authors

Aleksander Aleksandrov ^*
0009-0004-0020-9434
Bulgaria

Dimitar Iliev
0000-0002-1251-9833
Bulgaria

Banko Bankov
0009-0001-3400-2915
Bulgaria

Georgi Antov
0009-0007-2304-1410
Bulgaria

Svetozar Stoichev
0000-0001-8894-0838
Bulgaria

Publication Date

June 12, 2026

Submission Date

January 23, 2026

Acceptance Date

March 17, 2026

Published in Issue

Year 2026 Volume: 85 Number: 2

DOI

https://doi.org/10.26650/EurJBiol.2026.1869737

IZ

https://izlik.org/JA95RP62CD

Cite

RIS / Bibtex

APA

Aleksandrov, A., Iliev, D., Bankov, B., Antov, G., & Stoichev, S. (2026). ATM Inhibitor KU-60019 Induces Extracellular Vesicle Secretion in HeLa Cells. European Journal of Biology, 85(2), 137-147. https://doi.org/10.26650/EurJBiol.2026.1869737

AMA

1.Aleksandrov A, Iliev D, Bankov B, Antov G, Stoichev S. ATM Inhibitor KU-60019 Induces Extracellular Vesicle Secretion in HeLa Cells. Eur J Biol. 2026;85(2):137-147. doi:10.26650/EurJBiol.2026.1869737

Chicago

Aleksandrov, Aleksander, Dimitar Iliev, Banko Bankov, Georgi Antov, and Svetozar Stoichev. 2026. “ATM Inhibitor KU-60019 Induces Extracellular Vesicle Secretion in HeLa Cells”. European Journal of Biology 85 (2): 137-47. https://doi.org/10.26650/EurJBiol.2026.1869737.

EndNote

Aleksandrov A, Iliev D, Bankov B, Antov G, Stoichev S (June 1, 2026) ATM Inhibitor KU-60019 Induces Extracellular Vesicle Secretion in HeLa Cells. European Journal of Biology 85 2 137–147.

IEEE

[1]A. Aleksandrov, D. Iliev, B. Bankov, G. Antov, and S. Stoichev, “ATM Inhibitor KU-60019 Induces Extracellular Vesicle Secretion in HeLa Cells”, Eur J Biol, vol. 85, no. 2, pp. 137–147, June 2026, doi: 10.26650/EurJBiol.2026.1869737.

ISNAD

Aleksandrov, Aleksander - Iliev, Dimitar - Bankov, Banko - Antov, Georgi - Stoichev, Svetozar. “ATM Inhibitor KU-60019 Induces Extracellular Vesicle Secretion in HeLa Cells”. European Journal of Biology 85/2 (June 1, 2026): 137-147. https://doi.org/10.26650/EurJBiol.2026.1869737.

JAMA

1.Aleksandrov A, Iliev D, Bankov B, Antov G, Stoichev S. ATM Inhibitor KU-60019 Induces Extracellular Vesicle Secretion in HeLa Cells. Eur J Biol. 2026;85:137–147.

MLA

Aleksandrov, Aleksander, et al. “ATM Inhibitor KU-60019 Induces Extracellular Vesicle Secretion in HeLa Cells”. European Journal of Biology, vol. 85, no. 2, June 2026, pp. 137-4, doi:10.26650/EurJBiol.2026.1869737.

Vancouver

1.Aleksander Aleksandrov, Dimitar Iliev, Banko Bankov, Georgi Antov, Svetozar Stoichev. ATM Inhibitor KU-60019 Induces Extracellular Vesicle Secretion in HeLa Cells. Eur J Biol. 2026 Jun. 1;85(2):137-4. doi:10.26650/EurJBiol.2026.1869737