Research Article

Tunicamycin-Induced Endoplasmic Reticulum Stress Is Associated with Increased Hsp60 Expression, a Marker of the Mitochondrial Unfolded Protein Response, and Increased Apoptosis under Carboplatin Co-Treatment in Triple-Negative Breast Cancer Cells

Volume: 5 Number: 1 June 21, 2026
EN

Tunicamycin-Induced Endoplasmic Reticulum Stress Is Associated with Increased Hsp60 Expression, a Marker of the Mitochondrial Unfolded Protein Response, and Increased Apoptosis under Carboplatin Co-Treatment in Triple-Negative Breast Cancer Cells

Abstract

Objective: The present study aimed to investigate the effect of tunicamycin-induced endoplasmic reticulum (ER) stress on Hsp60 gene expression as a surrogate marker of mitochondrial unfolded protein response (UPRmt), and on cell death in response to carboplatin in human triple-negative breast cancer (TNBC) cells. Materials and Methods: The human TNBC cell line MDA-MB-231 was used as the experimental model. Cells were treated with 1 mM carboplatin and/or increasing concentrations of tunicamycin (1, 2, and 5 µg/mL) for 24 h. Gene expression levels of the mitochondrial chaperone Hsp60 were measured by real-time qPCR. Cell death was quantified by flow cytometry using FITC-Annexin V apoptosis/necrosis assay. Results: Neither carboplatin nor tunicamycin alone altered Hsp60 gene expression, whereas their combined treatment was associated with increased Hsp60 levels in a tunicamycin dose-dependent manner with 1.48-, 1.51-, and 1.59-fold increases at 1, 2, and 5 µg/mL, respectively. Likewise, compared to carboplatin alone, tunicamycin co-treatment was associated with increased carboplatin-induced apoptosis in a dose-dependent trend, with 80.18%, 98.12%, and 105.63% increases at 1, 2, and 5 µg/mL tunicamycin, respectively. Conclusion: Our findings suggest that ER stress alone does not alter Hsp60 expression, but tends to increase it in the presence of additional stress imposed by carboplatin in human TNBC cells. Moreover, UPRER and Hsp60 may act in coordination to drive the cell fate toward apoptosis under tunicamycin and carboplatin co-stress conditions. Understanding the interplay between UPRER and UPRmt in response to platinum-based chemotherapy will help identify novel therapeutic targets within the integrated stress adaptation networks that underlie chemosensitivity and chemoresistance in TNBC.

Keywords

Apoptosis, Carboplatin, Endoplasmic reticulum stress, Hsp60, Triple-negative breast cancer

Supporting Institution

No funding was received for this study.

Ethical Statement

Ethical approval was not required for this study because no human participants or animals were involved, and the study was conducted using a commercially available cell line.

Thanks

The author would like to thank Ondokuz Mayıs University KÖKMER Center for their assistance with flow cytometry used in the Annexin V cell death assay.

References

  1. Azab, B., Alassaf, A., Abu-Humdan, A., Dardas, Z., Almousa, H., Alsalem, M., Khabour, O., Hammad, H., Saleh, T., & Awidi, A. (2019). Genotoxicity of cisplatin and carboplatin in cultured human lymphocytes: a comparative study. Interdisciplinary Toxicology, 12(2), 93-97. https://doi.org/10.2478/intox-2019-0011
  2. Bravo, R., Vicencio, J. M., Parra, V., Troncoso, R., Munoz, J. P., Bui, M., Quiroga, C., Rodriguez, A. E., Verdejo, H. E., Ferreira, J., Iglewski, M., Chiong, M., Simmen, T., Zorzano, A., Hill, J. A., Rothermel, B. A., Szabadkai, G., & Lavandero, S. (2011). Increased ER-mitochondrial coupling promotes mitochondrial respiration and bioenergetics during early phases of ER stress. Journal of Cell Science, 124(Pt 13), 2143-2152. https://doi.org/10.1242/jcs.080762
  3. Chen, H., Zhang, D. M., Zhang, Z. P., Li, M. Z., & Wu, H. F. (2021). SIRT3-mediated mitochondrial unfolded protein response weakens breast cancer sensitivity to cisplatin. Genes & Genomics, 43(12), 1433-1444. https://doi.org/10.1007/s13258-021-01145-5
  4. Evinova, A., Hatokova, Z., Tatarkova, Z., Brodnanova, M., Dibdiakova, K., & Racay, P. (2022). Endoplasmic reticulum stress induces mitochondrial dysfunction but not mitochondrial unfolded protein response in SH-SY5Y cells. Molecular and Cellular Biochemistry, 477(3), 965-975. https://doi.org/10.1007/s11010-021-04344-6
  5. Fillmore, C. M., & Kuperwasser, C. (2008). Human breast cancer cell lines contain stem-like cells that self-renew, give rise to phenotypically diverse progeny and survive chemotherapy. Breast Cancer Research, 10(2), R25. https://doi.org/10.1186/bcr1982
  6. Forgie, B. N., Prakash, R., & Telleria, C. M. (2022). Revisiting the Anti-Cancer Toxicity of Clinically Approved Platinating Derivatives. International Journal of Molecular Sciences, 23(23), 15410. https://doi.org/10.3390/ijms232315410
  7. Gruber, L., Jobst, M., Kiss, E., Karasova, M., Englinger, B., Berger, W., & Del Favero, G. (2023). Intracellular remodeling associated with endoplasmic reticulum stress modifies biomechanical compliance of bladder cells. Cell Communication and Signaling, 21(1), 307. https://doi.org/10.1186/s12964-023-01295-x
  8. Han, X., Zhang, X., Li, H., Huang, S., Zhang, S., Wang, F., & Shi, Y. (2015). Tunicamycin enhances the antitumor activity of trastuzumab on breast cancer in vitro and in vivo. Oncotarget, 6(36), 38912-38925. https://doi.org/10.18632/oncotarget.5334
  9. Huang, S., Wang, D., Zhang, S., Huang, X., Wang, D., Ijaz, M., & Shi, Y. (2017). Tunicamycin potentiates paclitaxel-induced apoptosis through inhibition of PI3K/AKT and MAPK pathways in breast cancer. Cancer Chemotherapy and Pharmacology, 80(4), 685-696. https://doi.org/10.1007/s00280-017-3393-7
  10. Inigo, J. R., & Chandra, D. (2022). The mitochondrial unfolded protein response (UPR(mt)): shielding against toxicity to mitochondria in cancer. Journal of Hematology & Oncology, 15(1), 98. https://doi.org/10.1186/s13045-022-01317-0
APA
Arslan, M. A. (2026). Tunicamycin-Induced Endoplasmic Reticulum Stress Is Associated with Increased Hsp60 Expression, a Marker of the Mitochondrial Unfolded Protein Response, and Increased Apoptosis under Carboplatin Co-Treatment in Triple-Negative Breast Cancer Cells. Farabi Medical Journal, 5(1). https://doi.org/10.59518/farabimedj.1941014
AMA
1.Arslan MA. Tunicamycin-Induced Endoplasmic Reticulum Stress Is Associated with Increased Hsp60 Expression, a Marker of the Mitochondrial Unfolded Protein Response, and Increased Apoptosis under Carboplatin Co-Treatment in Triple-Negative Breast Cancer Cells. Farabi Medical Journal. 2026;5(1). doi:10.59518/farabimedj.1941014
Chicago
Arslan, M. Alper. 2026. “Tunicamycin-Induced Endoplasmic Reticulum Stress Is Associated With Increased Hsp60 Expression, a Marker of the Mitochondrial Unfolded Protein Response, and Increased Apoptosis under Carboplatin Co-Treatment in Triple-Negative Breast Cancer Cells”. Farabi Medical Journal 5 (1). https://doi.org/10.59518/farabimedj.1941014.
EndNote
Arslan MA (June 1, 2026) Tunicamycin-Induced Endoplasmic Reticulum Stress Is Associated with Increased Hsp60 Expression, a Marker of the Mitochondrial Unfolded Protein Response, and Increased Apoptosis under Carboplatin Co-Treatment in Triple-Negative Breast Cancer Cells. Farabi Medical Journal 5 1
IEEE
[1]M. A. Arslan, “Tunicamycin-Induced Endoplasmic Reticulum Stress Is Associated with Increased Hsp60 Expression, a Marker of the Mitochondrial Unfolded Protein Response, and Increased Apoptosis under Carboplatin Co-Treatment in Triple-Negative Breast Cancer Cells”, Farabi Medical Journal, vol. 5, no. 1, June 2026, doi: 10.59518/farabimedj.1941014.
ISNAD
Arslan, M. Alper. “Tunicamycin-Induced Endoplasmic Reticulum Stress Is Associated With Increased Hsp60 Expression, a Marker of the Mitochondrial Unfolded Protein Response, and Increased Apoptosis under Carboplatin Co-Treatment in Triple-Negative Breast Cancer Cells”. Farabi Medical Journal 5/1 (June 1, 2026). https://doi.org/10.59518/farabimedj.1941014.
JAMA
1.Arslan MA. Tunicamycin-Induced Endoplasmic Reticulum Stress Is Associated with Increased Hsp60 Expression, a Marker of the Mitochondrial Unfolded Protein Response, and Increased Apoptosis under Carboplatin Co-Treatment in Triple-Negative Breast Cancer Cells. Farabi Medical Journal. 2026;5. doi:10.59518/farabimedj.1941014.
MLA
Arslan, M. Alper. “Tunicamycin-Induced Endoplasmic Reticulum Stress Is Associated With Increased Hsp60 Expression, a Marker of the Mitochondrial Unfolded Protein Response, and Increased Apoptosis under Carboplatin Co-Treatment in Triple-Negative Breast Cancer Cells”. Farabi Medical Journal, vol. 5, no. 1, June 2026, doi:10.59518/farabimedj.1941014.
Vancouver
1.M. Alper Arslan. Tunicamycin-Induced Endoplasmic Reticulum Stress Is Associated with Increased Hsp60 Expression, a Marker of the Mitochondrial Unfolded Protein Response, and Increased Apoptosis under Carboplatin Co-Treatment in Triple-Negative Breast Cancer Cells. Farabi Medical Journal. 2026 Jun. 1;5(1). doi:10.59518/farabimedj.1941014