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Cancer Biol Ther. 2017 Feb;18(2):106-114. doi: 10.1080/15384047.2016.1250987. Epub 2016 Oct 27.

Suppression of B-RafV600E melanoma cell survival by targeting mitochondria using triphenyl-phosphonium-conjugated nitroxide or ubiquinone.

Author information

1
a Department of Biochemistry , Medical College of Wisconsin , Milwaukee , WI , USA.

Abstract

Most BRAF-mutated melanomas initially responsive to the FDA-approved inhibitors preferentially targeting B-Raf mutated in Val600 residue eventually relapse, requiring additional therapeutic modalities. Recent studies report the significance of metabolic reprograming in mitochondria for maintenance of BRAF-mutated melanomas and for development of their drug resistance to B-Raf inhibitors, providing a rationale for targeting mitochondria as a potential therapeutic strategy for melanoma. We therefore determined whether mitochondria-targeted metabolism-interfering agents can effectively suppress human B-RafV600E melanoma cell lines and their dabrafenib/PLX4032-resistant progenies using mitochondria-targeted carboxy-proxyl (Mito-CP) and ubiquinone (Mito-Q). These agents exhibited comparable efficacy to PLX4032 in suppressing SK-MEL28, A375, and RPMI-7951 cells in vitro. As determined in SK-MEL28 and A375 cells, Mito-CP induced apoptotic cell death mediated by mitochondrial membrane depolarization and subsequent oxidative stress, which PLX4032 could not induce. Of note, Mito-CP also effectively suppressed PLX4032-resistant progenies of SK-MEL28 and A375. Moreover, when orally administered, Mito-CP suppressed SK-MEL28 xenografts in mice as effectively as PLX4032 without serious adverse effects. These data demonstrate that mitochondria-targeted agents have therapeutic potential to effectively suppress BRAF-mutated melanomas via an effect(s) distinct from those of B-Raf inhibitors.

KEYWORDS:

B-Raf; Mito-CP; Mito-Q; drug resistance; melanoma; mitochondria

PMID:
27786591
PMCID:
PMC5362989
DOI:
10.1080/15384047.2016.1250987
[Indexed for MEDLINE]
Free PMC Article

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