Prostate apoptosis response-4 is involved in the apoptosis response to docetaxel in MCF-7 breast cancer cells

Author(s)

Pereira, Michelly C. ^{[1, 2]} ; De Bessa-Garcia, Simone A. ^{[1, 2]} ; Burikhanov, Ravshan ^[3] ; Pavanelli, Ana Carolina ^{[1, 2]} ; Antunes, Lourival ^{[1, 2]} ; Rangnekar, Vivek M. ^[3] ; Nagai, Maria A. ^{[1, 2]}

Affiliation

^[1] Univ Sao Paulo, Discipline Oncol, Dept Radiol & Oncol, Fac Med, BR-01246903 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Lab Genet Mol, Ctr Translat Res Oncol, BR-01246000 Sao Paulo - Brazil

^[3] Univ Kentucky, Lucille P Markey Canc Ctr, Lexington, KY - USA

• Document type: Journal article
• Source: International Journal of Oncology; v. 43, n. 2, p. 531-538, AUG 2013.
• Web of Science Citations: 11

Abstract

Experimental evidence indicates that prostate apoptosis response-4 (Par-4, also known as PAWR) is a key regulator of cancer cell survival and may be a target for cancer-selective targeted therapeutics. Par-4 was first identified in prostate cancer cells undergoing apoptosis. Both intracellular and extracellular Par-4 have been implicated in apoptosis. Relatively little is known about the role of Par-4 in breast cancer cell apoptosis. In this study, we sought to investigate the effects of Par-4 expression on cell proliferation, apoptosis and drug sensitivity in breast cancer cells. MCF-7 cells were stably transfected with expression vectors for Par-4, or transiently transfected with siRNA for Par-4 knockdown. Cell proliferation assays were performed using MTT and apoptosis was evaluated using acridine orange staining, fluorescence microscopy and flow cytometry. Par-4 overexpression reduced MCF-7 proliferation rates. Conversely, Par-4 knockdown led to increased MCF-7 proliferation. Par-4 downregulation also led to increased BCL-2 and reduced BID expression. Par-4 overexpression did not affect the cell cycle profile. However, MCF-7 cells with increased Par-4 expression showed reduced ERK phosphorylation, suggesting that the inhibition of cell proliferation promoted by Par-4 may be mediated by the MAPK/ERK1/2 pathway. MCF-7 cells with increased Par-4 expression showed a marginal increase in early apoptotic cells. Importantly, we found that Par-4 expression modulates apoptosis in response to docetaxel in MCF7 breast cancer cells. Par-4 exerts growth inhibitory effects on breast cancer cells and chemosensitizes them to docetaxel. (AU)

• FAPESP's process: 10/16543-5 - Study of the functional role of PAR-4 and SPARC in breast cancer cell survival and chemosensitivity
• Grantee: Maria Aparecida Nagai
• Support type: Regular Research Grants