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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

Chorein sensitive BCL-2 and Bax gene transcription and protein expression in ZF rhabdomyosarcoma cellsArithmetic means ± SEM (n=6) of the BCL-2 (A) and Bax (B) mRNA levels relative to GAPDH mRNA levels in ZF cells transfected with control siRNA (siNeg) or siRNA for chorein (siVPS13A). ** significant difference (p<0.01; unpaired t-test) C. Left: Arithmetic means ± SEM (n=6) of the BCL-2 protein levels compared to GAPDH levels in ZF cells transfected with control siRNA (siNeg) and siRNA for chorein (siVPS13A). Right: original Western blots of BCL-2 and GAPDH as loading control in ZF cells transfected with control siRNA (siNeg) or siRNA for chorein (siVPS13A). * significant difference (p<0.05; unpaired t-test).
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Figure 3: Chorein sensitive BCL-2 and Bax gene transcription and protein expression in ZF rhabdomyosarcoma cellsArithmetic means ± SEM (n=6) of the BCL-2 (A) and Bax (B) mRNA levels relative to GAPDH mRNA levels in ZF cells transfected with control siRNA (siNeg) or siRNA for chorein (siVPS13A). ** significant difference (p<0.01; unpaired t-test) C. Left: Arithmetic means ± SEM (n=6) of the BCL-2 protein levels compared to GAPDH levels in ZF cells transfected with control siRNA (siNeg) and siRNA for chorein (siVPS13A). Right: original Western blots of BCL-2 and GAPDH as loading control in ZF cells transfected with control siRNA (siNeg) or siRNA for chorein (siVPS13A). * significant difference (p<0.05; unpaired t-test).

Mentions: Additional experiments addressed the impact of chorein on the expression of anti-apoptotic protein B-cell lymphoma 2 (BCL-2) and of pro-apoptotic protein Bax. As illustrated in Fig. 3A, chorein silencing significantly decreased the BCL-2 (Fig. 3A) and increased the Bax (Fig. 3B) transcript levels in ZF rhabdomyosarcoma cells. Furthermore, chorein silencing decreased the BCL-2 protein abundance in ZF rhabdomyosarcoma cells (Fig. 3C).


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)

Chorein sensitive BCL-2 and Bax gene transcription and protein expression in ZF rhabdomyosarcoma cellsArithmetic means ± SEM (n=6) of the BCL-2 (A) and Bax (B) mRNA levels relative to GAPDH mRNA levels in ZF cells transfected with control siRNA (siNeg) or siRNA for chorein (siVPS13A). ** significant difference (p<0.01; unpaired t-test) C. Left: Arithmetic means ± SEM (n=6) of the BCL-2 protein levels compared to GAPDH levels in ZF cells transfected with control siRNA (siNeg) and siRNA for chorein (siVPS13A). Right: original Western blots of BCL-2 and GAPDH as loading control in ZF cells transfected with control siRNA (siNeg) or siRNA for chorein (siVPS13A). * significant difference (p<0.05; unpaired t-test).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 3: Chorein sensitive BCL-2 and Bax gene transcription and protein expression in ZF rhabdomyosarcoma cellsArithmetic means ± SEM (n=6) of the BCL-2 (A) and Bax (B) mRNA levels relative to GAPDH mRNA levels in ZF cells transfected with control siRNA (siNeg) or siRNA for chorein (siVPS13A). ** significant difference (p<0.01; unpaired t-test) C. Left: Arithmetic means ± SEM (n=6) of the BCL-2 protein levels compared to GAPDH levels in ZF cells transfected with control siRNA (siNeg) and siRNA for chorein (siVPS13A). Right: original Western blots of BCL-2 and GAPDH as loading control in ZF cells transfected with control siRNA (siNeg) or siRNA for chorein (siVPS13A). * significant difference (p<0.05; unpaired t-test).
Mentions: Additional experiments addressed the impact of chorein on the expression of anti-apoptotic protein B-cell lymphoma 2 (BCL-2) and of pro-apoptotic protein Bax. As illustrated in Fig. 3A, chorein silencing significantly decreased the BCL-2 (Fig. 3A) and increased the Bax (Fig. 3B) transcript levels in ZF rhabdomyosarcoma cells. Furthermore, chorein silencing decreased the BCL-2 protein abundance in ZF rhabdomyosarcoma cells (Fig. 3C).

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