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Chorein addiction in VPS13A overexpressing rhabdomyosarcoma cells.

Honisch S, Yu W, Liu G, Alesutan I, Towhid ST, Tsapara A, Schleicher S, Handgretinger R, Stournaras C, Lang F - Oncotarget (2015)

Bottom Line: Chorein encoded by VPS13A (vacuolar protein sorting-associated protein 13A) is defective in chorea-acanthocytosis.Chorein silencing significantly reduced the ratio of phosphorylated (and thus activated) to total phosphoinositide 3 kinase (PI-3K), pointing to inactivation of this crucial pro-survival signaling molecule.In cells with high chorein expression levels chorein silencing promotes apoptotic cell death, an effect paralleled by down-regulation of PI-3K activity and BCL-2/Bax expression ratio.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, University of Tübingen, Tübingen, Germany.

ABSTRACT
Chorein encoded by VPS13A (vacuolar protein sorting-associated protein 13A) is defective in chorea-acanthocytosis. Chorein fosters neuronal cell survival, cortical actin polymerization and cell stiffness. In view of its anti-apoptotic effect in neurons, we explored whether chorein is expressed in cancer cells and influences cancer cell survival. RT-PCR was employed to determine transcript levels, specific siRNA to silence chorein, FACS analysis to follow apoptosis and Western blotting to quantify protein abundance. Chorein transcripts were detected in various cancer cell types. The mRNA coding for chorein and chorein protein were most abundant in drug resistant, poorly differentiated human rhabdomyosarcoma cells. Chorein silencing significantly reduced the ratio of phosphorylated (and thus activated) to total phosphoinositide 3 kinase (PI-3K), pointing to inactivation of this crucial pro-survival signaling molecule. Moreover, chorein silencing diminished transcript levels and protein expression of anti-apoptotic BCL-2 and enhanced transcript levels of pro-apoptotic Bax. Silencing of chorein in rhabdomyosarcoma cells was followed by mitochondrial depolarization, caspase 3 activation and stimulation of early and late apoptosis. In conclusion, chorein is expressed in various cancer cells. In cells with high chorein expression levels chorein silencing promotes apoptotic cell death, an effect paralleled by down-regulation of PI-3K activity and BCL-2/Bax expression ratio.

No MeSH data available.


Related in: MedlinePlus

Resistance of CaCo2 cells to apoptotic effect of chorein silencingA. CaCo2 cells were stained with FITC conjugated Annexin V and propidium iodide (PI) and measured by FACS. Shown are arithmetic means ± SEM (n=3) of early (left) and late (right) apoptosis in non-transfected (control), transfected with negative control siRNA (siNeg) and with siRNA for chorein (siVPS13A) CaCo2 cells. B. Original dot-plots (PI/Annexin V) of a representative experiment demonstrating no significant difference between control and transfected cells.
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Figure 6: Resistance of CaCo2 cells to apoptotic effect of chorein silencingA. CaCo2 cells were stained with FITC conjugated Annexin V and propidium iodide (PI) and measured by FACS. Shown are arithmetic means ± SEM (n=3) of early (left) and late (right) apoptosis in non-transfected (control), transfected with negative control siRNA (siNeg) and with siRNA for chorein (siVPS13A) CaCo2 cells. B. Original dot-plots (PI/Annexin V) of a representative experiment demonstrating no significant difference between control and transfected cells.

Mentions: Apoptosis was evidenced from Annexin V and propidium iodide binding. As illustrated in Fig. 5A, B, chorein significantly enhanced the percentage of ZF rhabdomyosarcoma cells in early or late apoptosis. In contrast, chorein silencing of Caco2 cells (Suppl. Fig. 1A), which express only low levels of chorein (demonstrated in Fig. 1A) had almost no effect on apoptosis of these cells (Fig. 6A,B).


Chorein addiction in VPS13A overexpressing rhabdomyosarcoma cells.

Honisch S, Yu W, Liu G, Alesutan I, Towhid ST, Tsapara A, Schleicher S, Handgretinger R, Stournaras C, Lang F - Oncotarget (2015)

Resistance of CaCo2 cells to apoptotic effect of chorein silencingA. CaCo2 cells were stained with FITC conjugated Annexin V and propidium iodide (PI) and measured by FACS. Shown are arithmetic means ± SEM (n=3) of early (left) and late (right) apoptosis in non-transfected (control), transfected with negative control siRNA (siNeg) and with siRNA for chorein (siVPS13A) CaCo2 cells. B. Original dot-plots (PI/Annexin V) of a representative experiment demonstrating no significant difference between control and transfected cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496357&req=5

Figure 6: Resistance of CaCo2 cells to apoptotic effect of chorein silencingA. CaCo2 cells were stained with FITC conjugated Annexin V and propidium iodide (PI) and measured by FACS. Shown are arithmetic means ± SEM (n=3) of early (left) and late (right) apoptosis in non-transfected (control), transfected with negative control siRNA (siNeg) and with siRNA for chorein (siVPS13A) CaCo2 cells. B. Original dot-plots (PI/Annexin V) of a representative experiment demonstrating no significant difference between control and transfected cells.
Mentions: Apoptosis was evidenced from Annexin V and propidium iodide binding. As illustrated in Fig. 5A, B, chorein significantly enhanced the percentage of ZF rhabdomyosarcoma cells in early or late apoptosis. In contrast, chorein silencing of Caco2 cells (Suppl. Fig. 1A), which express only low levels of chorein (demonstrated in Fig. 1A) had almost no effect on apoptosis of these cells (Fig. 6A,B).

Bottom Line: Chorein encoded by VPS13A (vacuolar protein sorting-associated protein 13A) is defective in chorea-acanthocytosis.Chorein silencing significantly reduced the ratio of phosphorylated (and thus activated) to total phosphoinositide 3 kinase (PI-3K), pointing to inactivation of this crucial pro-survival signaling molecule.In cells with high chorein expression levels chorein silencing promotes apoptotic cell death, an effect paralleled by down-regulation of PI-3K activity and BCL-2/Bax expression ratio.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, University of Tübingen, Tübingen, Germany.

ABSTRACT
Chorein encoded by VPS13A (vacuolar protein sorting-associated protein 13A) is defective in chorea-acanthocytosis. Chorein fosters neuronal cell survival, cortical actin polymerization and cell stiffness. In view of its anti-apoptotic effect in neurons, we explored whether chorein is expressed in cancer cells and influences cancer cell survival. RT-PCR was employed to determine transcript levels, specific siRNA to silence chorein, FACS analysis to follow apoptosis and Western blotting to quantify protein abundance. Chorein transcripts were detected in various cancer cell types. The mRNA coding for chorein and chorein protein were most abundant in drug resistant, poorly differentiated human rhabdomyosarcoma cells. Chorein silencing significantly reduced the ratio of phosphorylated (and thus activated) to total phosphoinositide 3 kinase (PI-3K), pointing to inactivation of this crucial pro-survival signaling molecule. Moreover, chorein silencing diminished transcript levels and protein expression of anti-apoptotic BCL-2 and enhanced transcript levels of pro-apoptotic Bax. Silencing of chorein in rhabdomyosarcoma cells was followed by mitochondrial depolarization, caspase 3 activation and stimulation of early and late apoptosis. In conclusion, chorein is expressed in various cancer cells. In cells with high chorein expression levels chorein silencing promotes apoptotic cell death, an effect paralleled by down-regulation of PI-3K activity and BCL-2/Bax expression ratio.

No MeSH data available.


Related in: MedlinePlus