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Reduced ER-mitochondria connectivity promotes neuroblastoma multidrug resistance

ABSTRACT: Most cancer deaths result from progression of therapy resistant disease, yet our understanding of this phenotype is limited. Cancer therapies generate stress signals that act upon mitochondria to initiate apoptosis. Mitochondria isolated from neuroblastoma cells were exposed to tBid or Bim, death effectors activated by therapeutic stress. Multidrug resistant tumor cells obtained from children at relapse had markedly attenuated Bak and Bax oligomerization and cytochrome c release (surrogates for apoptotic commitment) in comparison with patient-matched tumor cells obtained at diagnosis. Electron microscopy identified reduced endoplasmic reticulum-mitochondria contacts (ERMCs) in therapy resistant cells, and genetically or biochemically reducing ERMCs in therapy sensitive tumors phenocopied resistance. ERMCs serve as platforms to transfer Ca2+ and bioactive lipids to mitochondria. Reduced Ca2+ transfer was found in some but not all resistant cells, and inhibiting transfer did not attenuate apoptotic signaling. In contrast, reduced ceramide synthesis and transfer was common to resistant cells and its inhibition induced stress resistance. We identify ERMCs as physiologic regulators of apoptosis via ceramide transfer and uncover a previously unrecognized mechanism for cancer multidrug resistance.

ORGANISM(S): Human Homo Sapiens

TISSUE(S): Cultured Cells

DISEASE(S): Cancer

SUBMITTER: Taekyung Yun

PROVIDER: ST002054 | MetabolomicsWorkbench | Thu Nov 18 00:00:00 GMT 2021

REPOSITORIES: MetabolomicsWorkbench

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