Preparation and antitumor activity of triphenylphosphine-based mitochondrial targeting polylactic acid nanoparticles loaded with 7-hydroxyl coumarin

Synthesis, anticancer activity and molecular docking study of triphenylphosphonium-linked derivatives of oleanolic acid

Lung cancer and breast cancer both are extremely threatening to humans, so it is needed to develop safe and effective drugs for the treatment of these two ailments. To improve the activity and selectivity of bioactive natural product oleanolic acid (OA), triphenylphosphonium moieties were introduced at different sites of the OA core skeleton. The in vitro antiproliferative activity screening results displayed that the anticancer activity of all target compounds was significantly improved, and some derivatives displayed strong selectivity for breast cancer cells (MCF-7) and lung cancer cells (A549) over the human normal liver cells (QSG-7701 cells). Compounds 6a (for A549 cells) and 5g (for MCF-7 cells) demonstrated the best selectivity (with SI of 12.18 and 7.72, respectively). The docking results showed that 5g and 6c could bind to and interact with PI3K protein through hydrogen bonds and intermolecular hydrophobic forces. These compounds are potential anti-MCF-7 agents and deserve further study.

Ursolic acid loaded tri-block copolymer nanoparticles based on triphenylphosphine for mitochondria-targeted cancer therapy

A novel biodegradable amphiphilic triblock copolymer, polyphosphate, polyethylene glycol, and polylactic acid (PAEEP-PEG-PLLA), was synthesized by twice ring-opening polymerization and triphenylphosphine (TPP) was grafted onto the block copolymer to synthesize a carrier material TPP-PAEEP-PEG-PLLA, which was identified by1H-nuclear magnetic resonance (1H-NMR) spectroscopy. The TPP-PAEEP-PEG-PLLA nanoparticles encapsulated with ursolic acid (UA) were prepared by the emulsion-solvent evaporation method and characterized by dynamic light scattering. The mitochondrial targeting ability of fluorescently labeled nanoparticles was evaluated by laser confocal microscopy. The average particle size and surface charge of the UA -loaded nanoparticle solution were 180.07 ± 1.67 nm and +15.57 ± 1.33 mV, respectively. The biocompatibility of nanoparticles was briefly evaluated by erythrocyte hemolysis assay.In vitrocell proliferation assay and scratch migration assay were performed to compare the difference in anti-tumor effect between UA and UA nanoparticles. The results showed that TPP-modified triblock copolymers had good mitochondrial targeting and improved the low bioavailability of UA, and UA nanoparticles exhibited more pronounced anti-tumor capabilities. In summary, the results suggested that our UA nanoparticles were a promising drug-targeted delivery system for the treatment of tumors.

Triphenylphosphonium-Functionalized Gold Nanorod/Zinc Oxide Core-Shell Nanocomposites for Mitochondrial-Targeted Phototherapy

Phototherapies, such as photothermal therapy (PTT) and photodynamic therapy (PDT), combined with novel all-in-one light-responsive nanocomposites have recently emerged as new therapeutic modalities for the treatment of cancer. Herein, we developed novel all-in-one triphenylphosphonium-functionalized gold nanorod/zinc oxide core-shell nanocomposites (CTPP-GNR@ZnO) for mitochondrial-targeted PTT/PDT owing to their good biocompatibility, tunable and high optical absorption, photothermal conversion efficiency, highest reactive oxygen species (ROS) generation, and high mitochondrial-targeting capability. Under laser irradiation of 780 nm, the CTPP-GNR@ZnO core-shell nanocomposites effectively produced heat in addition to generating ROS to induce cell death, implying a synergistic effect of mild PTT and PDT in combating cancer. Notably, the in vitro PTT/PDT effect of CTPP-GNR@ZnO core-shell nanocomposites exhibited effective cell ablation (95%) and induced significant intracellular ROS after the 780 nm laser irradiation for 50 min, indicating that CTPP in CTPP-GNR@ZnO core-shell nanocomposites can specifically target the mitochondria of CT-26 cells, as well as generate heat and ROS to completely kill cancer cells. Overall, this light-responsive nanocomposite-based phototherapy provides a new approach for cancer synergistic therapy.

Enhanced protection against hypoxia/reoxygenation-induced apoptosis in H9c2 cells by puerarin-loaded liposomes modified with matrix metalloproteinases-targeting peptide and triphenylphosphonium

Based on the inhibition of mitochondrial permeability transition pore (mPTP) opening, puerarin (PUE) has a good potential to reduce myocardial ischemia/reperfusion injury (MI/RI). However, the lack of targeting of free PUE makes it difficult to reach the mitochondria. In this paper, we constructed matrix metalloproteinase-targeting peptide (MMP-TP) and triphenylphosphonium (TPP) cation co-modified liposomes loaded with PUE (PUE@T/M-L) for mitochondria-targeted drug delivery. PUE@T/M-L had a favorable particle size of 144.9 ± 0.8 nm, an encapsulation efficiency of 78.9 ± 0.6%, and a sustained-release behavior. The results of cytofluorimetric experiments showed that MMP-TP and TPP double-modified liposomes (T/M-L) enhanced intracellular uptake, escaped lysosomal capture, and promoted drug targeting into mitochondria. In addition, PUE@T/M-L enhanced the viability of hypoxia-reoxygenation (H/R) injured H9c2 cells by inhibiting mPTP opening and reactive oxygen species (ROS) production, reducing Bax expression and increasing Bcl-2 expression. It was inferred that PUE@T/M-L delivered PUE into the mitochondria of H/R injured H9c2 cells, resulting in a significant increase in cellular potency. Based on the ability of MMP-TP to bind the elevated expression of matrix metalloproteinases (MMPs), T/M-L had excellent tropism for Lipopolysaccharide (LPS) -stimulated macrophages and can significantly reduce TNF-α and ROS levels, thus allowing both drug accumulation in ischemic cardiomyocytes and reducing inflammatory stimulation during MI/RI. Fluorescence imaging results of the targeting effect using a DiR probe also indicated that DiR@T/M-L could accumulate and retain in the ischemic myocardium. Taken together, these results demonstrated the promising application of PUE@T/M-L for mitochondria-targeted drug delivery to achieve maximum therapeutic efficacy of PUE.

Maintenance of mitochondrial homeostasis for Alzheimer's disease: Strategies and challenges

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases, and its early onset is closely related to mitochondrial energy metabolism. The brain is only 2% of body weight, but consumes 20% of total energy needs. Mitochondria are responsible for providing energy in cells, and maintaining their homeostasis ensures an adequate supply of energy to the brain. Mitochondrial homeostasis is constituted by mitochondrial quantity and quality control, which is dynamically regulated by mitochondrial energy metabolism, mitochondrial dynamics and mitochondrial quality control. Impaired energy metabolism of brain cells occurs early in AD, and maintaining mitochondrial homeostasis is a promising therapeutic target in the future. We summarized the mechanism of mitochondrial homeostasis in AD, its influence on the pathogenesis of early AD, strategies for maintaining mitochondrial homeostasis, and mitochondrial targeting strategies. This review concludes with the authors' opinions on future research and development for mitochondrial homeostasis of early AD.

Highly Stable Docetaxel-Loaded Nanoparticles Based on Poly(D,L-lactide)-b-Poly(ethylene glycol) for Cancer Treatment: Preparation, Characterization, and In Vitro Cytotoxicity Studies

Stability and narrow size distribution are among the main requirements that apply to drug formulations based on polymeric nanoparticles. In this study, we obtained a series of particles based on biodegradable poly(D,L-lactide)-b-poly(ethylene glycol) (P(D,L)LA_n-b-PEG₁₁₃) copolymers with varied hydrophobic P(D,L)LA block length n from 50 to 1230 monomer units stabilized by poly(vinyl alcohol) (PVA) by a simple "oil-in-water" emulsion method. We found that nanoparticles of P(D,L)LA_n-b-PEG₁₁₃ copolymers with relatively short P(D,L)LA block (n ≤ 180) are prone to aggregate in water. P(D,L)LA_n-b-PEG₁₁₃ copolymers with n ≥ 680 can form spherical unimodal particles with values of hydrodynamic diameter less than 250 nm and polydispersity less than 0.2. The aggregation behavior of P(D,L)LA_n-b-PEG₁₁₃ particles was elucidated in terms of tethering density and conformation of PEG chains at the P(D,L)LA core. Docetaxel (DTX) loaded nanoparticles based on P(D,L)LA₆₈₀-b-PEG₁₁₃ and P(D,L)LA₁₂₃₀-b-PEG₁₁₃ copolymers were formulated and studied. It was observed that DTX-loaded P(D,L)LA_n-b-PEG₁₁₃ (n = 680, 1230) particles are characterized by high thermodynamic and kinetic stability in aqueous medium. The cumulative release of DTX from the P(D,L)LA_n-b-PEG₁₁₃ (n = 680, 1230) particles is sustained. An increase in P(D,L)LA block length results in a decrease in DTX release rate. The in vitro antiproliferative activity and selectivity studies revealed that DTX-loaded P(D,L)LA₁₂₃₀-b-PEG₁₁₃ nanoparticles demonstrate better anticancer performance than free DTX. Favorable freeze-drying conditions for DTX nanoformulation based on P(D,L)LA₁₂₃₀-b-PEG₁₁₃ particles were also established.

A mitochondria-targeted nano-platform for pancreatic cancer therapy

Liposome is a conventional drug delivery system which has been widely used in the pharmacy field. However, its applications are greatly restricted in clinical practice by the disadvantages of cholesterol and nonselective distribution. Herein, a novel platform for anti-tumor drug delivery was developed by incorporating an amphiphilic stachydrine-octadecane conjugate (SS) as the mitochondria-targeting molecule onto the triptolide-liposome surfaces (SS-TP LPs). The polyethylene glycol (PEG) and the suitable particle size (about 133 nm) of liposomes facilitated their stabilities, the long half-life in blood and the escape from the rapid elimination. The SS-TP LPs were internalized and accumulated into the mitochondria of cancer cells in a time-dependent manner, followed by triggering permeabilization of the mitochondrial outer membrane by inhibiting Bcl-2, and then further caused greater cancer cell death via releasing cytochrome C and initiating a cascade of caspase 3 reactions. In the Pan02 tumor-bearing mice, the SS-TP LPs showed significant efficacy in inhibiting tumor growth and reducing tumor size but synchronously exhibited specific mitochondria-targeting and much lower subacute toxicity compared with the free TP and TP LPs. Our study suggests that SS-TP LPs can be a promising anticancer drug delivery system for mitochondria-targeted therapy in pancreatic cancer.