title: The miR-21/PTEN/Akt signaling pathway is involved in the anti-tumoral effects of zoledronic acid in human breast cancer cell lines.
abstract: Preclinical data indicate a direct anti-tumor effect of zoledronic acid (ZA) outside the skeleton, but its molecular mechanism is still not completely clarified. The aim of this study was to investigate the anti-cancer effects of ZA in human breast cancer cell lines, suggesting that they may in part be mediated via the miR-21/PTEN/Akt signaling pathway. The effect of ZA on cell viability was measured by MTT assay, and cell death induction was analyzed using either a double AO/EtBr staining and M30 ELISA assay. A Proteome Profiler Human Apoptosis Array was executed to evaluate the molecular basis of ZA-induced apoptosis. Cell cycle analysis was executed by flow cytometry. The effect of ZA on miR-21 expression was quantified by qRT-PCR, and the amount of PTEN protein and its targets were analyzed by Western blot. ZA inhibited cell growth in a concentration- and time-dependent manner, through the activation of cell death pathways and arrest of cell cycle progression. ZA downregulated the expression of miR-21, resulting in dephosphorilation of Akt and Bad and in a significant increase of p21 and p27 proteins expression. These results were observed also in MDA-MB-231 cells, commonly used as an experimental model of bone metastasis of breast cancer. This study revealed, for the first time, an involvement of the miR-21/PTEN/Akt signaling pathway in the mechanism of ZA anti-cancer actions in breast cancer cells. We would like to underline that this pathway is present both in the hormone responsive BC cell line (MCF-7) as well as in a triple negative cell line (MDA-MB-231). Taken together these results reinforce the use of ZA in clinical practice, suggesting the role of miR-21 as a possible mediator of its therapeutic efficacy.
authors.affiliation: Section of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy. martina.fragni@libero.it.
authors.forename: M
authors.initials: M
authors.lastname: Fragni
authors.affiliation: Section of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
authors.forename: S A
authors.initials: SA
authors.lastname: Bonini
authors.affiliation: Section of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Bettinsoli
authors.affiliation: Section of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Bodei
authors.affiliation: Department of Medical, Surgery and Health Sciences, University of Trieste, Piazza Ospitale 1, 34129, Trieste, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Generali
authors.affiliation: Breast Unit and Molecular Therapy and Pharmacogenomic Unit, Istituti Ospitalieri di Cremona, Viale Concordia 1, Cremona, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Bottini
authors.affiliation: Section of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
authors.forename: P F
authors.initials: PF
authors.lastname: Spano
authors.affiliation: Section of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Memo
authors.affiliation: Section of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Sigala
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004164:Diphosphonates / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D035683:MicroRNAs / Q000378:metabolism*; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D000077211:Zoledronic Acid
chemical_list: D000970:Antineoplastic Agents; D004164:Diphosphonates; D007093:Imidazoles; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D000077211:Zoledronic Acid; D051057:Proto-Oncogene Proteins c-akt; D051059:PTEN Phosphohydrolase
keywords: Akt; Breast cancer; PTEN; Zoledronic acid; miR-21