Forskolin increases the effect of everolimus on aromatase inhibitor-resistant breast cancer cells

Takanori Hayashi, Masahiro Hikichi, Jun Yukitake, Toru Wakatsuki, Eiji Nishio, Toshiaki Utsumi, Nobuhiro Harada

Research output: Contribution to journalArticle

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Abstract

Aromatase inhibitor (AI) resistance is a major obstacle in the treatment of estrogen receptor-positive breast cancer. Everolimus (EVE) ameliorates AI-resistant breast cancer and is therefore used in cancer treatment. However, some patients show resistance to EVE. Here, we used 30 clones of long-term estrogen-deprived (LTED) MCF-7 cells as a model of AI-resistant breast cancer. We examined changes in protein phosphatase type 2A (PP2A) and cancerous inhibitor of PP2A (CIP2A), a negative regulator of PP2A, in LTED cells treated with EVE. In LTED cells with high sensitivity to EVE, CIP2A expression decreased at low EVE concentrations; however, in LTED cells poorly sensitive to EVE, CIP2A and PP2A did not change upon exposure to EVE. Therefore, we hypothesized that there is a relation between expression of CIP2A and sensitivity to EVE. Knockdown of CIP2A increased the sensitivity to EVE in three clones poorly sensitive to EVE. Additionally, we found that treatment with FSK, which activates PP2A, increased the sensitivity of the cells to EVE. Our data point to CIP2A and PP2A as novel therapeutic targets for AI-resistant breast cancer.

Original languageEnglish
Pages (from-to)23451-23461
Number of pages11
JournalOncotarget
Volume9
Issue number34
DOIs
Publication statusPublished - 01-05-2018

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Aromatase Inhibitors
Colforsin
Protein Phosphatase 2
Breast Neoplasms
Estrogens
Everolimus
Clone Cells
MCF-7 Cells
Therapeutics
Estrogen Receptors

All Science Journal Classification (ASJC) codes

  • Oncology

Cite this

Hayashi, T., Hikichi, M., Yukitake, J., Wakatsuki, T., Nishio, E., Utsumi, T., & Harada, N. (2018). Forskolin increases the effect of everolimus on aromatase inhibitor-resistant breast cancer cells. Oncotarget, 9(34), 23451-23461. https://doi.org/10.18632/oncotarget.25217
Hayashi, Takanori ; Hikichi, Masahiro ; Yukitake, Jun ; Wakatsuki, Toru ; Nishio, Eiji ; Utsumi, Toshiaki ; Harada, Nobuhiro. / Forskolin increases the effect of everolimus on aromatase inhibitor-resistant breast cancer cells. In: Oncotarget. 2018 ; Vol. 9, No. 34. pp. 23451-23461.
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Hayashi, T, Hikichi, M, Yukitake, J, Wakatsuki, T, Nishio, E, Utsumi, T & Harada, N 2018, 'Forskolin increases the effect of everolimus on aromatase inhibitor-resistant breast cancer cells', Oncotarget, vol. 9, no. 34, pp. 23451-23461. https://doi.org/10.18632/oncotarget.25217

Forskolin increases the effect of everolimus on aromatase inhibitor-resistant breast cancer cells. / Hayashi, Takanori; Hikichi, Masahiro; Yukitake, Jun; Wakatsuki, Toru; Nishio, Eiji; Utsumi, Toshiaki; Harada, Nobuhiro.

In: Oncotarget, Vol. 9, No. 34, 01.05.2018, p. 23451-23461.

Research output: Contribution to journalArticle

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