Simultaneous targeting of peripheral and brain tumors with a therapeutic nanoparticle to disrupt metabolic adaptability at both sites

Brain metastasis of advanced breast cancer often results in deleterious consequences. Metastases to the brain lead to significant challenges in treatment options, as the blood– brain barrier (BBB) prevents conventional therapy. Thus, we hypothesized that creation of a nanoparticle (NP) that distributes to both primary tumor site and across the BBB for secondary brain tumor can be extremely beneficial. Here, we report a simple target- ing strategy to attack both the primary breast and secondary brain tumors utilizing a single NP platform. The nature of these mitochondrion-targeted, BBB-penetrating NPs allow for simultaneous targeting and drug delivery to the hyperpolarized mitochondrial membrane of the extracranial primary tumor site in addition to tumors at the brain. By utilizing a combination of such dual anatomical distributing NPs loaded with therapeu- tics, we demonstrate a proof-of-concept idea to combat the increased metabolic plasticity of brain metastases by lowering two major energy sources, oxidative phosphorylation (OXPHOS) and glycolysis. By utilizing complementary studies and genomic analyses, we demonstrate the utility of a chemotherapeutic prodrug to decrease OXPHOS and glycolysis by pairing with a NP loaded with pyruvate dehydrogenase kinase 1 inhibitor. Decreasing glycolysis aims to combat the metabolic flexibility of both primary and sec- ondary tumors for therapeutic outcome. We also address the in vivo safety parameters by addressing peripheral neuropathy and neurobehavior outcomes. Our results also demonstrate that this combination therapeutic approach utilizes mitochondrial genome targeting strategy to overcome DNA repair–based chemoresistance mechanisms. We treated the MDA-MB-231-BR cells cells with cisplatin or T-Platin-M-NP and then we performed RNA sequencing analysis to understand the expression profiles of OXPHOS, nucleotide excision pathway and nuclear encoded mitochondrial genes. A primary xenoraft tumor model was generated using MDA-MB-231-BR cells in BALB/c nude mice and treated with cisplatin, 2-DG, T-Platin-M-NP or T-Platin-M-NP+2-DG. Tumor samples were harvested at the end of the study and then performed expression profiling analysis using the data obtained from the RNA -seq of tumor samples and study expression of genes related OXPHOS, glycolysis and execision repair pathways. A dual tumor model was generated using MDA-MB-231-BRLuc cells in BALB/c nude mice and treated with cisplatin or T-Platin-M-NP+T-Mito-DCA-NP. Tumor samples were harvested at the end of the study and then performed expression profiling analysis using the data obtained from the RNA -seq of tumor samples and study expression of genes related to OXPHOS, glycolysis, Fatty acid oxidation, apoptosis and various repair pathways.