TY  - JOUR
A1  - Bartel, Karin
A1  - Pein, Helmut
A1  - Popper, Bastian
A1  - Schmitt, Sabine
A1  - Janaki-Raman, Sudha
A1  - Schulze, Almut
A1  - Lengauer, Florian
A1  - Koeberle, Andreas
A1  - Werz, Oliver
A1  - Zischka, Hans
A1  - Müller, Rolf
A1  - Vollmar, Angelika M.
A1  - Schwarzenberg, Karin von
T1  - Connecting lysosomes and mitochondria – a novel role for lipid metabolism in cancer cell death
T2  - Cell Communication and Signaling
N2  - Background
The understanding of lysosomes has been expanded in recent research way beyond their view as cellular trash can. Lysosomes are pivotal in regulating metabolism, endocytosis and autophagy and are implicated in cancer. Recently it was discovered that the lysosomal V-ATPase, which is known to induce apoptosis, interferes with lipid metabolism in cancer, yet the interplay between these organelles is poorly understood.

Methods
LC-MS/MS analysis was performed to investigate lipid distribution in cells. Cell survival and signaling pathways were analyzed by means of cell biological methods (qPCR, Western Blot, flow cytometry, CellTiter-Blue). Mitochondrial structure was analyzed by confocal imaging and electron microscopy, their function was determined by flow cytometry and seahorse measurements.

Results
Our data reveal that interfering with lysosomal function changes composition and subcellular localization of triacylglycerids accompanied by an upregulation of PGC1α and PPARα expression, master regulators of energy and lipid metabolism. Furthermore, cardiolipin content is reduced driving mitochondria into fission, accompanied by a loss of membrane potential and reduction in oxidative capacity, which leads to a deregulation in cellular ROS and induction of mitochondria-driven apoptosis. Additionally, cells undergo a metabolic shift to glutamine dependency, correlated with the fission phenotype and sensitivity to lysosomal inhibition, most prominent in Ras mutated cells.

Conclusion
This study sheds mechanistic light on a largely uninvestigated triangle between lysosomes, lipid metabolism and mitochondrial function. Insight into this organelle crosstalk increases our understanding of mitochondria-driven cell death. Our findings furthermore provide a first hint on a connection of Ras pathway mutations and sensitivity towards lysosomal inhibitors.
KW  - lysosome
KW  - V-ATPase
KW  - mitochondria
KW  - fission
KW  - apoptosis
KW  - lipid metabolism
KW  - cardiolipin
Y1  - 2019
UR  - https://opus.bibliothek.uni-wuerzburg.de/frontdoor/index/index/docId/22152
UR  - https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-221524
VL  - 17
ER  -