Resistance to the mTOR inhibitor everolimus is reversed by the downregulation of survivin in breast cancer cells

Everolimus (RAD001) is an inhibitor of mammalian target of rapamycin used in combination with exemestane to treat hormone receptor-positive advanced breast cancer. However, not all patients are equally sensitive to RAD001 and certain patients develop resistance. Therefore, the present study analyzed...

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Bibliographic Details
Published in:Oncology letters 2017-09, Vol.14 (3), p.3832-3838
Main Authors: Taglieri, Ludovica, De Iuliis, Francesca, Giuffrida, Anna, Giantulli, Sabrina, Silvestri, Ida, Scarpa, Susanna
Format: Article
Language:English
Subjects:
Apoptosis
Autophagy
Breast cancer
Cancer therapies
Cell cycle
chemoresistance
Chemotherapy
Cytotoxicity
Development and progression
Drug resistance
Drug therapy
Everolimus
Genetic aspects
Health aspects
Inhibitor drugs
Kinases
Patient outcomes
Proteins
Rodents
survivin
Targeted cancer therapy
Transcription factors
Tumors
YM155
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Summary:Everolimus (RAD001) is an inhibitor of mammalian target of rapamycin used in combination with exemestane to treat hormone receptor-positive advanced breast cancer. However, not all patients are equally sensitive to RAD001 and certain patients develop resistance. Therefore, the present study analyzed the mechanisms involved in the resistance of breast cancer cells to RAD001 in order to identify a potential tool to overcome it. The effects of RAD001 on the inhibition of cell viability, on the induction of apoptosis and autophagy and on the regulation of survivin, an anti-apoptotic protein, were evaluated in two breast cancer cell lines: BT474 (luminal B) and MCF7 (luminal A). RAD001 was demonstrated to induce autophagy in the two cell lines at following a short period of treatment (4 h) and to induce apoptosis exclusively in BT474 cells following longer periods of treatment (48 h). RAD001 induced the downregulation of survivin in BT474 cells and its upregulation in MCF7 cells. Consequently, inhibiting survivin with YM155 resulted in the acquired resistance of MCF7 cells to RAD001 being reverted, restoring RAD001-induced apoptosis. These data demonstrated that RAD001 exerted anti-proliferative and pro-apoptotic effects on breast cancer cells, but that these effects were repressed by the simultaneous up-regulation of survivin. Finally, the results demonstrated that inhibiting the expression of survivin resulted in the restoration of the anti-neoplastic activity of RAD001.
ISSN:1792-1074
1792-1082
DOI:10.3892/ol.2017.6597