Voltage dependent anion channel-1 regulates death receptor mediated apoptosis by enabling cleavage of caspase-8Reportar como inadecuado




Voltage dependent anion channel-1 regulates death receptor mediated apoptosis by enabling cleavage of caspase-8 - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

BMC Cancer

, 10:380

Cell and molecular biology

Abstract

BackgroundActivation of the extrinsic apoptosis pathway by tumour necrosis factor related apoptosis inducing ligand TRAIL is a novel therapeutic strategy for treating cancer that is currently under clinical evaluation. Identification of molecular biomarkers of resistance is likely to play an important role in predicting clinical anti tumour activity. The involvement of the mitochondrial type 1 voltage dependent anion channel VDAC1 in regulating apoptosis has been highly debated. To date, a functional role in regulating the extrinsic apoptosis pathway has not been formally excluded.

MethodsWe carried out stable and transient RNAi knockdowns of VDAC1 in non-small cell lung cancer cells, and stimulated the extrinsic apoptotic pathway principally by incubating cells with the death ligand TRAIL. We used in-vitro apoptotic and cell viability assays, as well as western blot for markers of apoptosis, to demonstrate that TRAIL-induced toxicity is VDAC1 dependant. Confocal microscopy and mitochondrial fractionation were used to determine the importance of mitochondria for caspase-8 activation.

ResultsHere we show that either stable or transient knockdown of VDAC1 is sufficient to antagonize TRAIL mediated apoptosis in non-small cell lung cancer NSCLC cells. Specifically, VDAC1 is required for processing of procaspase-8 to its fully active p18 form at the mitochondria. Loss of VDAC1 does not alter mitochondrial sensitivity to exogenous caspase-8-cleaved BID induced mitochondrial depolarization, even though VDAC1 expression is essential for TRAIL dependent activation of the intrinsic apoptosis pathway. Furthermore, expression of exogenous VDAC1 restores the apoptotic response to TRAIL in cells in which endogenous VDAC1 has been selectively silenced.

ConclusionsExpression of VDAC1 is required for full processing and activation of caspase-8 and supports a role for mitochondria in regulating apoptosis signaling via the death receptor pathway.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2407-10-380 contains supplementary material, which is available to authorized users.

Download fulltext PDF



Autor: Alex D Chacko - Fabio Liberante - Ian Paul - Daniel B Longley - Dean A Fennell

Fuente: https://link.springer.com/







Documentos relacionados