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ABCG8‑mediated sterol efflux increases cancer cell progression via the LRP6/Wnt/β‑catenin signaling pathway in radiotherapy‑resistant MDA‑MB‑231 triple‑negative breast cancer cells

  • Authors:
    • Young Shin Ko
    • Ju Yeong Won
    • Hana Jin
    • Nam Binh Nguyen
    • Yaeram Won
    • Vedaste Nsanzimana
    • Seung Pil Yun
    • Sang Won Park
    • Hye Jung Kim

  • View Affiliations

  • Published online on: March 20, 2025     https://doi.org/10.3892/ijmm.2025.5521
  • Article Number: 80

  • Copyright: © Ko et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

Expression levels of ATP‑binding cassette (ABC) transporters are known to be increased in various tumor cells, including in breast cancer, and they are responsible for mediating drug resistance, leading to treatment failure. In the present study, gene expression array analysis revealed that among ABC transporter subtypes, ABC subfamily G member 8 (ABCG8) was one of the most increased in radiotherapy‑resistant triple‑negative breast cancer (RT‑R‑TNBC) cells compared with in TNBC cells. ABCG8 is involved in sterol efflux; however, its role in cancer is not well known. Therefore, the present study investigated the effect of ABCG8 on tumor progression in RT‑R‑TNBC cells. Gene expression profiling was conducted using the QuantiSeq 3' mRNA‑Seq Service, followed by western blotting to confirm protein levels. Loss‑of‑function assays using small interfering RNA (si) transfection were performed to assess the roles of ABCG8 and its regulatory signaling pathways. RT‑R‑MDA‑MB‑231 cells exhibited increased cholesterol levels in both cells and the surrounding media via induction of sterol regulatory element binding protein 1 (mature form) and fatty acid synthase. siABCG8 transfection increased intracellular cholesterol levels but decreased cholesterol levels in the media, indicating an accumulation of cholesterol inside cells. Additionally, RT‑R‑MDA‑MB‑231 cells exhibited increased levels of β‑catenin compared with MDA‑MB‑231 cells, which was significantly reduced by ABCG8 knockdown. Furthermore, ABCG8 knockdown led to cell cycle arrest in the G2/M phase in RT‑R‑MDA‑MB‑231 cells by reducing Polo‑like kinase 1 (PLK1) and Cyclin B1 expression. RT‑R‑MDA‑MB‑231 cells also exhibited increased phosphorylated‑low‑density lipoprotein (LDL) receptor‑related protein 6 (LRP6) levels compared with MDA‑MB‑231 cells, and these were decreased by siABCG8 transfection. LRP6 siRNA transfection decreased β‑catenin, PLK1 and Cyclin B1 expression. In addition, feedback mechanisms such as liver X receptor and inducible degrader of LDL were decreased in RT‑R‑MDA‑MB‑231 cells under normal conditions compared with in MDA‑MB‑231 cells. To the best of our knowledge, the present study was the first to suggest that the cholesterol exported by ABCG8, not inside the cells, may affect cancer progression via the LRP6/Wnt/β‑catenin signaling pathway in RT‑R‑TNBC. The regulation of this pathway may offer a potential therapeutic strategy for the treatment of RT‑R‑TNBC.
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May-2025
Volume 55 Issue 5

Print ISSN: 1107-3756
Online ISSN:1791-244X

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  • Journal Metrics
  • Impact Factor: 5.7
  • Ranked Medicine Research and Experimental
    (total number of cites)
  • CiteScore: 12.3
  • CiteScore Rank: Q1: #28/347 Biochemistry, Genetics and Molecular Biology
  • Source Normalized Impact per Paper (SNIP): 1.022
  • SCImago Journal Rank (SJR): 1.167
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Spandidos Publications style
Ko YS, Won JY, Jin H, Nguyen NB, Won Y, Nsanzimana V, Yun SP, Park SW and Kim HJ: ABCG8‑mediated sterol efflux increases cancer cell progression via the LRP6/Wnt/β‑catenin signaling pathway in radiotherapy‑resistant MDA‑MB‑231 triple‑negative breast cancer cells. Int J Mol Med 55: 80, 2025.
APA
Ko, Y.S., Won, J.Y., Jin, H., Nguyen, N.B., Won, Y., Nsanzimana, V. ... Kim, H.J. (2025). ABCG8‑mediated sterol efflux increases cancer cell progression via the LRP6/Wnt/β‑catenin signaling pathway in radiotherapy‑resistant MDA‑MB‑231 triple‑negative breast cancer cells. International Journal of Molecular Medicine, 55, 80. https://doi.org/10.3892/ijmm.2025.5521
MLA
Ko, Y. S., Won, J. Y., Jin, H., Nguyen, N. B., Won, Y., Nsanzimana, V., Yun, S. P., Park, S. W., Kim, H. J."ABCG8‑mediated sterol efflux increases cancer cell progression via the LRP6/Wnt/β‑catenin signaling pathway in radiotherapy‑resistant MDA‑MB‑231 triple‑negative breast cancer cells". International Journal of Molecular Medicine 55.5 (2025): 80.
Chicago
Ko, Y. S., Won, J. Y., Jin, H., Nguyen, N. B., Won, Y., Nsanzimana, V., Yun, S. P., Park, S. W., Kim, H. J."ABCG8‑mediated sterol efflux increases cancer cell progression via the LRP6/Wnt/β‑catenin signaling pathway in radiotherapy‑resistant MDA‑MB‑231 triple‑negative breast cancer cells". International Journal of Molecular Medicine 55, no. 5 (2025): 80. https://doi.org/10.3892/ijmm.2025.5521