Limits...
AF1q: a novel mediator of basal and 4-HPR-induced apoptosis in ovarian cancer cells.

Tiberio P, Cavadini E, Callari M, Daidone MG, Appierto V - PLoS ONE (2012)

Bottom Line: Through gene silencing, AF1q was found functionally involved in 4-HPR-induced apoptosis in A2780, an ovarian cancer cell line highly sensitive to retinoid growth inhibitory and apoptotic effects.Inhibition of the signaling intermediates of the 4-HPR apoptotic cascade showed that AF1q upregulation was depended on prior generation of ROS, induction of ER stress response, JNK activation, and PLAB upmodulation.The study expands the knowledge of the 4-HPR mechanism of action, which has not yet been completely elucidated, identifying AF1q as a novel mediator of retinoid anticancer activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. paola.tiberio@istitutotumori.mi.it

ABSTRACT

Background: Fenretinide (4-HPR) is a synthetic retinoid that exhibits potent antitumor and chemopreventive activities against different malignancies, including ovarian tumors. We previously showed that in ovarian cancer cells, 4-HPR induces apoptosis through a signaling cascade starting from reactive oxygen species (ROS) generation and involving endoplasmic reticulum (ER) stress response, Jun N-terminal Kinase (JNK) activation, and induction of the proapoptotic PLAcental Bone morphogenetic protein (PLAB). Since recent studies have shown that the oncogene ALL1-fused from chromosome 1q (AF1q), a retinoic acid target gene, is implicated in apoptosis induction by several therapeutic agents, we investigated its possible involvement in the apoptosis induced by 4-HPR in ovarian cancer cells.

Methodology/principal findings: Protein expression analysis, performed in ovarian cancer cells and extended to other histotypes (breast, neuroblastoma, and cervical), revealed that 4-HPR enhanced AF1q expression in cancer cells sensitive to the retinoid but not in resistant cells. Through gene silencing, AF1q was found functionally involved in 4-HPR-induced apoptosis in A2780, an ovarian cancer cell line highly sensitive to retinoid growth inhibitory and apoptotic effects. Inhibition of the signaling intermediates of the 4-HPR apoptotic cascade showed that AF1q upregulation was depended on prior generation of ROS, induction of ER stress response, JNK activation, and PLAB upmodulation. Finally, we found that direct overexpression of AF1q, in the absence of external stimuli, increased apoptosis in ovarian cancer cell lines.

Conclusions/significance: The study expands the knowledge of the 4-HPR mechanism of action, which has not yet been completely elucidated, identifying AF1q as a novel mediator of retinoid anticancer activity. In addition, we demonstrate, for the first time, that AF1q plays a role in the onset of basal apoptosis in ovarian cancer cells, thus providing new information about the activity of this protein whose biologic functions are mostly unknown.

Show MeSH

Related in: MedlinePlus

Effects of different retinoids on AF1q expression in A2780 cells.Western blot analysiso for AF1q expression and caspase-3 cleavage in A2780 cells treated for 24 hours with 10 µM RA or 4-MPR, or 3 µM 4-oxo-4-HPR. As a control for loading, the blot was incubated with actin antibody.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3383705&req=5

pone-0039968-g003: Effects of different retinoids on AF1q expression in A2780 cells.Western blot analysiso for AF1q expression and caspase-3 cleavage in A2780 cells treated for 24 hours with 10 µM RA or 4-MPR, or 3 µM 4-oxo-4-HPR. As a control for loading, the blot was incubated with actin antibody.

Mentions: Analysis of the association between AF1q expression and tumor growth inhibitory and apoptotic effects was extended to other natural and synthetic retinoids, i.e., RA, and N-(4-methoxyphenyl)retinamide (4-MPR) and 4-oxo-N-(4-hydroxyphenyl)retinamide (4-oxo-4-HPR), two 4-HPR metabolites. We previously demonstrated that 4-oxo-4-HPR has a growth inhibitory effect (IC50 = 0.6 µM, at 72 hours) and induces apoptosis in A2780 cells, whereas 4-MPR and RA do not affect such growth (IC50>10 µM, at 72 hours for both retinoids) [27]–[29]. As shown in Figure 3, in A2780 cells the treatment with RA, as well as with 4-MPR, did not affect either AF1q expression or caspase-3 activation, whereas 4-oxo-4-HPR treatment led to an increase in AF1q expression and to caspase-3 cleavage (Figure 3). The data demonstrated that retinoid-induced AF1q upregulation was associated with the ability of the compound to inhibit cell growth and to induce apoptosis.


AF1q: a novel mediator of basal and 4-HPR-induced apoptosis in ovarian cancer cells.

Tiberio P, Cavadini E, Callari M, Daidone MG, Appierto V - PLoS ONE (2012)

Effects of different retinoids on AF1q expression in A2780 cells.Western blot analysiso for AF1q expression and caspase-3 cleavage in A2780 cells treated for 24 hours with 10 µM RA or 4-MPR, or 3 µM 4-oxo-4-HPR. As a control for loading, the blot was incubated with actin antibody.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3383705&req=5

pone-0039968-g003: Effects of different retinoids on AF1q expression in A2780 cells.Western blot analysiso for AF1q expression and caspase-3 cleavage in A2780 cells treated for 24 hours with 10 µM RA or 4-MPR, or 3 µM 4-oxo-4-HPR. As a control for loading, the blot was incubated with actin antibody.
Mentions: Analysis of the association between AF1q expression and tumor growth inhibitory and apoptotic effects was extended to other natural and synthetic retinoids, i.e., RA, and N-(4-methoxyphenyl)retinamide (4-MPR) and 4-oxo-N-(4-hydroxyphenyl)retinamide (4-oxo-4-HPR), two 4-HPR metabolites. We previously demonstrated that 4-oxo-4-HPR has a growth inhibitory effect (IC50 = 0.6 µM, at 72 hours) and induces apoptosis in A2780 cells, whereas 4-MPR and RA do not affect such growth (IC50>10 µM, at 72 hours for both retinoids) [27]–[29]. As shown in Figure 3, in A2780 cells the treatment with RA, as well as with 4-MPR, did not affect either AF1q expression or caspase-3 activation, whereas 4-oxo-4-HPR treatment led to an increase in AF1q expression and to caspase-3 cleavage (Figure 3). The data demonstrated that retinoid-induced AF1q upregulation was associated with the ability of the compound to inhibit cell growth and to induce apoptosis.

Bottom Line: Through gene silencing, AF1q was found functionally involved in 4-HPR-induced apoptosis in A2780, an ovarian cancer cell line highly sensitive to retinoid growth inhibitory and apoptotic effects.Inhibition of the signaling intermediates of the 4-HPR apoptotic cascade showed that AF1q upregulation was depended on prior generation of ROS, induction of ER stress response, JNK activation, and PLAB upmodulation.The study expands the knowledge of the 4-HPR mechanism of action, which has not yet been completely elucidated, identifying AF1q as a novel mediator of retinoid anticancer activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. paola.tiberio@istitutotumori.mi.it

ABSTRACT

Background: Fenretinide (4-HPR) is a synthetic retinoid that exhibits potent antitumor and chemopreventive activities against different malignancies, including ovarian tumors. We previously showed that in ovarian cancer cells, 4-HPR induces apoptosis through a signaling cascade starting from reactive oxygen species (ROS) generation and involving endoplasmic reticulum (ER) stress response, Jun N-terminal Kinase (JNK) activation, and induction of the proapoptotic PLAcental Bone morphogenetic protein (PLAB). Since recent studies have shown that the oncogene ALL1-fused from chromosome 1q (AF1q), a retinoic acid target gene, is implicated in apoptosis induction by several therapeutic agents, we investigated its possible involvement in the apoptosis induced by 4-HPR in ovarian cancer cells.

Methodology/principal findings: Protein expression analysis, performed in ovarian cancer cells and extended to other histotypes (breast, neuroblastoma, and cervical), revealed that 4-HPR enhanced AF1q expression in cancer cells sensitive to the retinoid but not in resistant cells. Through gene silencing, AF1q was found functionally involved in 4-HPR-induced apoptosis in A2780, an ovarian cancer cell line highly sensitive to retinoid growth inhibitory and apoptotic effects. Inhibition of the signaling intermediates of the 4-HPR apoptotic cascade showed that AF1q upregulation was depended on prior generation of ROS, induction of ER stress response, JNK activation, and PLAB upmodulation. Finally, we found that direct overexpression of AF1q, in the absence of external stimuli, increased apoptosis in ovarian cancer cell lines.

Conclusions/significance: The study expands the knowledge of the 4-HPR mechanism of action, which has not yet been completely elucidated, identifying AF1q as a novel mediator of retinoid anticancer activity. In addition, we demonstrate, for the first time, that AF1q plays a role in the onset of basal apoptosis in ovarian cancer cells, thus providing new information about the activity of this protein whose biologic functions are mostly unknown.

Show MeSH
Related in: MedlinePlus