La Grange, GA, United States
La Grange, GA, United States

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PubMed | NanoTherapeutics Research Laboratory and University of Georgia
Type: Journal Article | Journal: Proceedings of the National Academy of Sciences of the United States of America | Year: 2014

Chemoresistance of cisplatin therapy is related to extensive repair of cisplatin-modified DNA in the nucleus by the nucleotide excision repair (NER). Delivering cisplatin to the mitochondria to attack mitochondrial genome lacking NER machinery can lead to a rationally designed therapy for metastatic, chemoresistant cancers and might overcome the problems associated with conventional cisplatin treatment. An engineered hydrophobic mitochondria-targeted cisplatin prodrug, Platin-M, was constructed using a strain-promoted alkyne-azide cycloaddition chemistry. Efficient delivery of Platin-M using a biocompatible polymeric nanoparticle (NP) based on biodegradable poly(lactic-co-glycolic acid)-block-polyethyleneglycol functionalized with a terminal triphenylphosphonium cation, which has remarkable activity to target mitochondria of cells, resulted in controlled release of cisplatin from Platin-M locally inside the mitochondrial matrix to attack mtDNA and exhibited otherwise-resistant advanced cancer sensitive to cisplatin-based chemotherapy. Identification of an optimized targeted-NP formulation with brain-penetrating properties allowed for delivery of Platin-M inside the mitochondria of neuroblastoma cells resulting in 17 times more activity than cisplatin. The remarkable activity of Platin-M and its targeted-NP in cisplatin-resistant cells was correlated with the hyperpolarization of mitochondria in these cells and mitochondrial bioenergetics studies in the resistance cells further supported this hypothesis. This unique dual-targeting approach to controlled mitochondrial delivery of cisplatin in the form of a prodrug to attack the mitochondrial genome lacking NER machinery and in vivo distribution of the delivery vehicle in the brain suggested previously undescribed routes for cisplatin-based therapy.


Pathak R.K.,NanoTherapeutics Research Laboratory | Pathak R.K.,University of Georgia | Marrache S.,NanoTherapeutics Research Laboratory | Marrache S.,University of Georgia | And 4 more authors.
ACS Chemical Biology | Year: 2014

Tumor growth is fueled by the use of glycolysis, which normal cells use only in the scarcity of oxygen. Glycolysis makes tumor cells resistant to normal death processes. Targeting this unique tumor metabolism can provide an alternative strategy to selectively destroy the tumor, leaving normal tissue unharmed. The orphan drug dichloroacetate (DCA) is a mitochondrial kinase inhibitor that has the ability to show such characteristics. However, its molecular form shows poor uptake and bioavailability and limited ability to reach its target mitochondria. Here, we describe a targeted molecular scaffold for construction of a multiple DCA loaded compound, Mito-DCA, with three orders of magnitude enhanced potency and cancer cell specificity compared to DCA. Incorporation of a lipophilic triphenylphosphonium cation through a biodegradable linker in Mito-DCA allowed for mitochondria targeting. Mito-DCA did not show any significant metabolic effects toward normal cells but tumor cells with dysfunctional mitochondria were affected by Mito-DCA, which caused a switch from glycolysis to glucose oxidation and subsequent cell death via apoptosis. Effective delivery of DCA to the mitochondria resulted in significant reduction in lactate levels and played important roles in modulating dendritic cell (DC) phenotype evidenced by secretion of interleukin-12 from DCs upon activation with tumor antigens from Mito-DCA treated cancer cells. Targeting mitochondrial metabolic inhibitors to the mitochondria could lead to induction of an efficient antitumor immune response, thus introducing the concept of combining glycolysis inhibition with immune system to destroy tumor. © 2014 American Chemical Society.

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