Cancer Therapeutics
Other Therapeutics
Mito-DCA: a mitochondria targeted molecular scaffold for efficacious delivery of metabolic modulator dichloroacetate
ACS Chem Biol. 2014 May 16;9(5):1178-87. doi: 10.1021/cb400944y. Epub 2014 Mar
25.

Mito-DCA: a mitochondria targeted molecular scaffold for efficacious delivery of
metabolic modulator dichloroacetate.

Pathak RK(1), Marrache S, Harn DA, Dhar S.

Author information:
(1)NanoTherapeutics Research Laboratory, Department of Chemistry and ‡Department
of Infectious Diseases, University of Georgia , Athens, Georgia 30602, United
States.

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.

Detouring of cisplatin to access mitochondrial genome for overcoming resistance
Proc Natl Acad Sci U S A. 2014 Jul 22;111(29):10444-9. doi:
10.1073/pnas.1405244111. Epub 2014 Jul 7.

Detouring of cisplatin to access mitochondrial genome for overcoming resistance.

Marrache S(1), Pathak RK(1), Dhar S(2).

Author information:
(1)NanoTherapeutics Research Laboratory, Department of Chemistry, and.
(2)NanoTherapeutics Research Laboratory, Department of Chemistry, andDepartment
of Physiology and Pharmacology, University of Georgia, Athens, GA 30602
shanta@uga.edu.

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.

Ex vivo programming of dendritic cells by mitochondria-targeted nanoparticles to produce interferon-gamma for cancer immunotherapy
ACS Nano. 2013 Aug 27;7(8):7392-402. doi: 10.1021/nn403158n. Epub 2013 Aug 6.

Ex vivo programming of dendritic cells by mitochondria-targeted nanoparticles to
produce interferon-gamma for cancer immunotherapy.

Marrache S(1), Tundup S, Harn DA, Dhar S.

Author information:
(1)NanoTherapeutics Research Laboratory, Department of Chemistry, University of
Georgia, Athens, Georgia 30602, United States.

One of the limitations for clinical applications of dendritic cell (DC)-based cancer immunotherapy is the low potency in generating tumor antigen specific T cell responses. We examined the immunotherapeutic potential of a mitochondria targeted nanoparticle (NP) based on a biodegradable polymer and zinc phthalocyanine (ZnPc) photosensitizer (T-ZnPc-NPs). Here, we report that tumor antigens generated from treatment of breast cancer cells with T-ZnPc-NPs upon light stimulation activate DCs to produce high levels of interferon-gamma, an important cytokine considered as a product of T and natural killer cells. The remarkable ex vivo DC stimulation ability of this tumor cell supernatant is a result of an interleukin (IL)-12/IL-18 autocrine effect. These findings contribute to the understanding of how in situ light activation amplifies the host immune responses when NPs deliver the photosensitizer to the mitochondria and open up the possibility of using mitochondria-targeted-NP-treated, light-activated cancer cell supernatants as possible vaccines.

Copper-free click-chemistry platform to functionalize cisplatin prodrugs
Chemistry. 2014 Jun 2;20(23):6861-5. doi: 10.1002/chem.201402573. Epub 2014 Apr
23.

Copper-free click-chemistry platform to functionalize cisplatin prodrugs.

Pathak RK(1), McNitt CD, Popik VV, Dhar S.

Author information:
(1)NanoTherapeutics Research Laboratory, Department of Chemistry, University of
Georgia, Athens, GA 30602 (USA), Fax: (+1) 706-542-9454
http://shanta.chem.uga.edu.

The ability to rationally design and construct a platform technology to develop new platinum(IV) [Pt(IV)] prodrugs with functionalities for installation of targeting moieties, delivery systems, fluorescent reporters from a single precursor with the ability to release biologically active cisplatin by using well-defined chemistry is critical for discovering new platinum-based therapeutics. With limited numbers of possibilities considering the sensitivity of Pt(IV) centers, we used a strain-promoted azide-alkyne cycloaddition approach to provide a platform, in which new functionalities can easily be installed on cisplatin prodrugs from a single Pt(IV) precursor. The ability of this platform to be incorporated in nanodelivery vehicle and conjugation to fluorescent reporters were also investigated.

Ex vivo generation of functional immune cells by mitochondria-targeted photosensitization of cancer cells
Methods Mol Biol. 2015;1265:113-22. doi: 10.1007/978-1-4939-2288-8_9.

Ex vivo generation of functional immune cells by mitochondria-targeted
photosensitization of cancer cells.

Marrache S(1), Tundup S, Harn DA, Dhar S.

Author information:
(1)NanoTherapeutics Research Laboratory, Department of Chemistry, University of
Georgia, Athens, GA, 30602, USA.

Stimulating the immune system for potent immune therapy against cancer is potentially a revolutionary method to eradicate cancer. Tumors stimulated with photosensitizers (PSs) not only kill cancer cells but also help to boost the immune system. We recently reported that tumor-associated antigens (TAAs) generated by delivery of a mitochondria acting PS zinc phthalocyanine (ZnPc) to MCF-7 breast cancer cells followed by laser irradiation can lead to ex vivo stimulation of mouse bone marrow-derived dendritic cells (BMDCs). The antigens generated from the breast cancer cells were also found to cause significant DC maturation and the activated DCs were able to stimulate T cells to cytotoxic CD8(+) T cells. In this protocol, we describe methods to engineer a mitochondria-targeted biodegradable nanoparticle (NP) formulation, T-ZnPc-NPs for delivery of ZnPc to the mitochondria of MCF-7 cells, subsequent photodynamic therapy (PDT) using a long wavelength laser irradiation to produce TAAs, DC stimulation by the TAAs to secrete interferon-gamma (IFN-γ), and matured DC-driven T-cell activation.

Biodegradable synthetic high-density lipoprotein nanoparticles for atherosclerosis
Proc Natl Acad Sci U S A. 2013 Jun 4;110(23):9445-50. doi:
10.1073/pnas.1301929110. Epub 2013 May 13.

Biodegradable synthetic high-density lipoprotein nanoparticles for
atherosclerosis.

Marrache S(1), Dhar S.

Author information:
(1)NanoTherapeutics Research Laboratory, Department of Chemistry, University of
Georgia, Athens, GA 30602, USA.

Atherosclerosis remains one of the most common causes of death in the United States and throughout the world because of the lack of early detection. Macrophage apoptosis is a major contributor to the instability of atherosclerotic lesions. Development of an apoptosis targeted high-density lipoprotein (HDL)-mimicking nanoparticle (NP) to carry contrast agents for early detection of vulnerable plaques and the initiation of preventative therapies that exploit the vascular protective effects of HDL can be attractive for atherosclerosis. Here, we report the construction of a synthetic, biodegradable HDL-NP platform for detection of vulnerable plaques by targeting the collapse of mitochondrial membrane potential that occurs during apoptosis. This HDL mimic contains a core of biodegradable poly(lactic-co-glycolic acid), cholesteryl oleate, and a phospholipid bilayer coat that is decorated with triphenylphosphonium (TPP) cations for detection of mitochondrial membrane potential collapse. The lipid layer provides the surface for adsorption of apolipoprotein (apo) A-I mimetic 4F peptide, and the core contains diagnostically active quantum dots (QDs) for optical imaging. In vitro uptake, detection of apoptosis, and cholesterol binding studies indicated promising detection ability and therapeutic potential of TPP-HDL-apoA-I-QD NPs. In vitro studies indicated the potential of these NPs in reverse cholesterol transport. In vivo biodistribution and pharmacokinetics indicated favorable tissue distribution, controlled pharmacokinetic parameters, and significant triglyceride reduction for i.v.-injected TPP-HDL-apoA-I-QD NPs in rats. These HDL NPs demonstrate excellent biocompatibility, stability, nontoxic, and nonimmunogenic properties, which prove to be promising for future translation in early plaque diagnosis and might find applications to prevent vulnerable plaque progression.

Engineering of blended nanoparticle platform for delivery of mitochondria-acting therapeutics
Proc Natl Acad Sci U S A. 2012 Oct 2;109(40):16288-93. doi:
10.1073/pnas.1210096109. Epub 2012 Sep 18.

Engineering of blended nanoparticle platform for delivery of mitochondria-acting
therapeutics.

Marrache S(1), Dhar S.

Author information:
(1)Nano Therapeutics Research Laboratory, Department of Chemistry, University of
Georgia, Athens, GA 30602, USA.

Mitochondrial dysfunctions cause numerous human disorders. A platform technology based on biodegradable polymers for carrying bioactive molecules to the mitochondrial matrix could be of enormous potential benefit in treating mitochondrial diseases. Here we report a rationally designed mitochondria-targeted polymeric nanoparticle (NP) system and its optimization for efficient delivery of various mitochondria-acting therapeutics by blending a targeted poly(d,l-lactic-co-glycolic acid)-block (PLGA-b)-poly(ethylene glycol) (PEG)-triphenylphosphonium (TPP) polymer (PLGA-b-PEG-TPP) with either nontargeted PLGA-b-PEG-OH or PLGA-COOH. An optimized formulation was identified through in vitro screening of a library of charge- and size-varied NPs, and mitochondrial uptake was studied by qualitative and quantitative investigations of cytosolic and mitochondrial fractions of cells treated with blended NPs composed of PLGA-b-PEG-TPP and a triblock copolymer containing a fluorescent quantum dot, PLGA-b-PEG-QD. The versatility of this platform was demonstrated by studying various mitochondria-acting therapeutics for different applications, including the mitochondria-targeting chemotherapeutics lonidamine and α-tocopheryl succinate for cancer, the mitochondrial antioxidant curcumin for Alzheimer’s disease, and the mitochondrial uncoupler 2,4-dinitrophenol for obesity. These biomolecules were loaded into blended NPs with high loading efficiencies. Considering efficacy, the targeted PLGA-b-PEG-TPP NP provides a remarkable improvement in the drug therapeutic index for cancer, Alzheimer’s disease, and obesity compared with the nontargeted construct or the therapeutics in their free form. This work represents the potential of a single, programmable NP platform for the diagnosis and targeted delivery of therapeutics for mitochondrial dysfunction-related diseases.

Formulation and optimization of mitochondria-targeted polymeric nanoparticles
Methods Mol Biol. 2015;1265:103-12. doi: 10.1007/978-1-4939-2288-8_8.

Formulation and optimization of mitochondria-targeted polymeric nanoparticles.

Marrache S(1), Pathak RK, Dhar S.

Author information:
(1)NanoTherapeutics Research Laboratory, Department of Chemistry, University of
Georgia, Athens, GA, 30606, USA.

Targeted delivery of therapeutics to the mitochondria of cells without alteration of drug properties can be a vital technique in the treatment of a variety of mitochondrial-dysfunction-related diseases. Herein, we describe a detailed protocol for synthesis and characterization of a functionalized polymer to build mitochondria-targeted nanoparticles (NPs). The block polymer was decorated with a lipophilic triphenylphosphonium (TPP) cation for mitochondrial trafficking of payload-loaded polymeric NPs. TPP-based lipophilic cations have the ability to cross the mitochondrial membrane. A mitochondria-targeted block copolymer poly(DL-lactide-co-glycolide)-b-polyethylene glycol-TPP and a nontargeted poly(DL-lactide-co-glycolide)-b-polyethylene glycol polymer were synthesized and their NPs were prepared. A nanoprecipitation method combined with polymer blending technology was adopted in order to get suitable size and charged NPs for efficient mitochondrial trafficking.

Targeted nanoparticles in mitochondrial medicine
Wiley Interdiscip Rev Nanomed Nanobiotechnol. 2014 Oct 27. doi:
10.1002/wnan.1305. [Epub ahead of print]

Targeted nanoparticles in mitochondrial medicine.

Pathak RK(1), Kolishetti N, Dhar S.

Author information:
(1)NanoTherapeutics Research Laboratory, Department of Chemistry, University of
Georgia, Athens, GA, USA.

Mitochondria, the so-called ‘energy factory of cells’ not only produce energy but also contribute immensely in cellular mortality management. Mitochondrial dysfunctions result in various diseases including but not limited to cancer, atherosclerosis, and neurodegenerative diseases. In the recent years, targeting mitochondria emerged as an attractive strategy to control mitochondrial dysfunction-related diseases. Despite the desire to direct therapeutics to the mitochondria, the actual task is more difficult due to the highly complex nature of the mitochondria. The potential benefits of integrating nanomaterials with properties such as biodegradability, magnetization, and fluorescence into a single object of nanoscale dimensions can lead to the development of hybrid nanomedical platforms for targeting therapeutics to the mitochondria. Only a handful of nanoparticles based on metal oxides, gold nanoparticles, dendrons, carbon nanotubes, and liposomes were recently engineered to target mitochondria. Most of these materials face tremendous challenges when administered in vivo due to their limited biocompatibility. Biodegradable polymeric nanoparticles emerged as eminent candidates for effective drug delivery. In this review, we highlight the current advancements in the development of biodegradable nanoparticle platforms as effective targeting tools for mitochondrial medicine. For further resources related to this article, please visit the WIREs website. Conflict of interest: S.D. discloses financial interest in Partikula LLC, a biotechnology company; and Partikula did not support the aforementioned work.

Nanocarriers for tracking and treating diseases
Curr Med Chem. 2013;20(28):3500-14.

Nanocarriers for tracking and treating diseases.

Marrache S(1), Pathak RK, Darley KL, Choi JH, Zaver D, Kolishetti N, Dhar S.

Author information:
(1)NanoTherapeutics Research Laboratory, Department of Chemistry, University of
Georgia, Athens, GA 30602, USA.

Site directed drug delivery with high efficacy is the biggest challenge in the area of current pharmaceuticals. Biodegradable polymer-based controlled release nanoparticle platforms could be beneficial for targeted delivery of therapeutics and contrast agents for a myriad of important human diseases. Biodegradable nanoparticles, which can be engineered to load multiple drugs with varied physicochemical properties, contrast agents, and cellular or intracellular component targeting moieties, have emerged as potential alternatives for tracking and treating human diseases. In this review, we will highlight the current advances in the design and execution of such platforms for their potential application in the diagnosis and treatment of variety of diseases ranging from cancer to Alzheimer’s and we will provide a critical analysis of the associated challenges for their possible clinical translation.