Basic Research
Copyright ©2006 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. May 14, 2006; 12(18): 2895-2900
Published online May 14, 2006. doi: 10.3748/wjg.v12.i18.2895
Partial Beclin 1 silencing aggravates doxorubicin- and Fas-induced apoptosis in HepG2 cells
Fanny Daniel, Agnès Legrand, Dominique Pessayre, Nathalie Vadrot, Véronique Descatoire, Dominique Bernuau
Fanny Daniel, Agnès Legrand, Dominique Pessayre, Véronique Descatoire, Dominique Bernuau, Institut National de la Santé et de la Recherche Médicale, INSERM, U773, Centre de Recherche Bichat Beaujon CRB3, BP 416, F-75018, Paris, France; Université paris 7 Denis Diderot, site Bichat, BP 416, F-75018, Paris, France
Nathalie Vadrot, Université paris 7 Denis Diderot, site Bichat, BP 416, F-75018, Paris, France
Correspondence to: Fanny Daniel, U773 INSERM (équipe 3), Faculté de Médecine Xavier Bichat, 16 rue Henri Huchard, Paris 75018, France. fdaniel@bichat.inserm.fr
Telephone: +33-1-44856211 Fax: +33-1-44856207
Received: August 2, 2005
Revised: August 28, 2005
Accepted: October 9, 2005
Published online: May 14, 2006
Abstract

AIM: To investigate the role of Beclin 1 on the susceptibility of HepG2 cells to undergo apoptosis after anti-Fas antibody or doxorubicin treatment.

METHODS: Beclin 1 silencing was achieved using RNA interference. DNA ploidy, the percentage of apoptotic cells and the mitochondrial membrane potential were assessed by flow cytometry. Levels of Beclin 1, Bcl-XL and cytochrome c, and the cleavage of poly (ADP-ribose) polymerase (PARP) were assayed by using Western blots.

RESULTS: Beclin 1 expression decreased by 75% 72 h after Beclin 1 siRNA transfection. Partial Beclin 1 silencing significantly increased the percentage of subG1 cells 24 and 40 h after treatment with doxorubicin or anti-Fas antibody, respectively, and this potentiation was abrogated by treatment with a pan-caspase inhibitor. Partial Beclin 1 silencing also increased PARP cleavage, mitochondrial membrane depolarization and cytosolic cytochrome c. The pro-apoptotic consequences of partial Beclin 1 silencing were not associated with a decline in Bcl-XL expression.

CONCLUSION: Partial Beclin 1 silencing aggravates mitochondrial permeabilization and apoptosis in HepG2 cells treated with an anti-Fas antibody or with doxorubicin.

Keywords: Beclin 1; Apoptosis; HepG2 cells; Anti-Fas antibody; Doxorubicin